WO2015141647A1 - Aluminum alloy sheet for structural material - Google Patents
Aluminum alloy sheet for structural material Download PDFInfo
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- WO2015141647A1 WO2015141647A1 PCT/JP2015/057774 JP2015057774W WO2015141647A1 WO 2015141647 A1 WO2015141647 A1 WO 2015141647A1 JP 2015057774 W JP2015057774 W JP 2015057774W WO 2015141647 A1 WO2015141647 A1 WO 2015141647A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
- C22F1/053—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with zinc as the next major constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
- C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/10—Alloys based on aluminium with zinc as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
- C22F1/047—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with magnesium as the next major constituent
Definitions
- the present invention relates to a high-strength aluminum alloy plate for a structural material that has improved workability and excellent corrosion resistance.
- the aluminum alloy plate of the present invention is a rolled plate, which is a plate obtained by subjecting a plate produced by rolling to aging at room temperature for 2 weeks or more after solution treatment and quenching treatment, before forming into a structural material and artificial This refers to the plate before age hardening.
- the structure of the plate aged at room temperature in the present invention refers to the structure of the plate after aging at room temperature for 2 weeks or more after the solution treatment and quenching treatment.
- the composition and tempering (solution treatment and quenching) of the JIS to AA6000 series aluminum alloy plates which are used in the above-mentioned automobile panels, are excellent in formability, strength, corrosion resistance, low alloy composition and recyclability. Control of the treatment, and further, the artificial age hardening treatment, is far from achieving the high strength.
- the 7000 series aluminum alloy which is an Al—Zn—Mg series aluminum alloy
- SCC stress corrosion cracking
- composition control of 7000 series aluminum alloy extruded material excellent in both strength and SCC resistance and structure control of precipitates have been conventionally proposed.
- conventional structure control such as composition control and precipitates in a 7000 series aluminum alloy plate according to the small practical use of the plate.
- Patent Document 1 the molten metal is cold-rolled after rapid solidification, and further, crystal precipitates in the crystal grains of the 7000 series aluminum alloy plate after artificial age hardening treatment are measured by a 400 times optical microscope.
- the size (converted to equivalent circle equivalent diameter) is 3.0 ⁇ m or less, and the average area fraction is 4.5% or less to improve strength and elongation.
- Patent Documents 2 and 3 in order to increase the strength and SCC resistance of a 7000 series plate for a structural material, the ingot is repeatedly rolled in a warm working region after forging, and the structure Is fine. This is because, by making the structure finer, a large tilt grain boundary having an orientation difference of 20 ° or more, which causes a potential difference between the grain boundary and the grain boundary, which causes a decrease in SCC resistance, is suppressed. This is to obtain a texture having a small angle grain boundary of 25 ° or more.
- such warm rolling is repeated because the conventional hot rolling and cold rolling methods cannot obtain a texture in which such a low-angle grain boundary is 25% or more. ing. Therefore, since the process is greatly different from the conventional method, it is difficult to say that it is a practical method for producing a plate.
- the extruded material is completely different from the rolled plate in its manufacturing process such as a hot working process, and the resulting structure of crystal grains and precipitates is, for example, a fibrous form in which the crystal grains are elongated in the extrusion direction.
- the crystal grains are basically different from a rolled plate having equiaxed grains.
- the object of the present invention is to provide an automobile member having both strength and formability and excellent corrosion resistance even after aging at room temperature as a rolled plate produced by the conventional method. It is to provide a 7000 series aluminum alloy plate for structural materials.
- the gist of the aluminum alloy sheet for structural material of the present invention is, in mass%, Zn: 3.0 to 6.0%, Mg: 2.5 to 4.5%, Cu: 0.00.
- the Zn content [Zn] and the Mg content [Mg] satisfy [Zn] ⁇ ⁇ 0.3 [Mg] +4.5, and the balance Is an Al—Zn—Mg-based aluminum alloy plate having a composition composed of Al and inevitable impurities, and is observed with a transmission electron microscope of 60000 times in a structure in which this plate is aged at room temperature after solution treatment and quenching treatment.
- the average composition ratio (Zn / Mg) of Zn and Mg in the grain boundary precipitates is 0.5 to 3.0, and a plate aged at room temperature after the solution treatment and quenching treatment, (I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more. Or (II) Particles observed with a transmission electron microscope at 60000 times in the structure of the plate after one of the one-stage artificial aging treatments for 12 to 36 hours at a heat treatment temperature of 100 to 150 ° C.
- the average composition ratio (Zn / Mg) of Zn and Mg in the inner precipitate is in the range of 1.5 to 3.5.
- the present inventors reduced the Zn content for improving the corrosion resistance, while using a 7000 series aluminum alloy plate having a composition in which the Mg content was increased to ensure strength and formability, the grains of the plate structure aged at room temperature. Focusing on the precipitates in the boundaries and grains, the effect of the composition of these precipitates on the properties was analyzed.
- the present invention can improve the balance between strength and ductility (formability) and BH properties, even for a 7000 series aluminum alloy plate with a reduced Zn content.
- a structural 7000 series aluminum alloy plate having both strength and formability hereinafter also referred to as formability or workability
- excellent corrosion resistance such as SCC resistance
- the measurement of the structure by the TEM is not a state of a plate that has not been aged at room temperature immediately after the tempering treatment, but as a guideline. This is a plate after aging at room temperature (room temperature standing) for more than a week, and is performed on the plate before forming into a structural material and before artificial age hardening treatment.
- the aluminum alloy plate referred to in the present invention is a plate produced by rolling, and the ingot is hot-rolled after soaking, further cold-rolled into a cold-rolled plate, and further subjected to solution treatment and quenching treatment, etc.
- the aluminum alloy plate referred to in the present invention defines the room temperature aged structure of the 7000 series aluminum alloy plate produced as described above, and is formed into a structural material for use as a material aluminum alloy plate. is there. For this reason, it refers to a plate after the plate manufactured as described above is aged at room temperature (room temperature standing), and before being formed into a structural material as an application and before artificial age hardening treatment.
- artificial age hardening is also simply referred to as artificial ageing
- artificial age hardening is simply referred to as artificial ageing.
- Al alloy composition (Aluminum alloy composition) First, the chemical component composition of the aluminum alloy sheet of the present invention will be described below, including reasons for limiting each element. In addition,% display of content of each element means the mass% altogether.
- the chemical composition of the aluminum alloy sheet of the present invention combines strength and formability, which are required characteristics for structural materials such as automobile members intended in the present invention, as a rolled sheet produced by a conventional method. It is a prerequisite for satisfying corrosion resistance.
- the Al-Zn-Mg-Cu-based 7000 series aluminum alloy composition in the present invention is a composition in which the Mg content is increased in order to secure strength while suppressing the Zn content in order to improve the corrosion resistance. .
- the chemical composition of the aluminum alloy sheet of the present invention is, by mass, Zn: 3.0 to 6.0%, Mg: 2.5 to 4.5%, Cu: 0.05 to 0.5. %, And the Zn content [Zn] and the Mg content [Mg] satisfy [Zn] ⁇ ⁇ 0.3 [Mg] +4.5, with the balance being Al and inevitable It shall consist of impurities.
- Zr 0.05 to 0.3%
- Mn 0.1 to 1.5%
- Cr 0.05 to 0.3%
- Sc 0.05
- One type or two or more types of up to 0.3% may be selectively included.
- one or two of Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1% may be selectively included. .
- Zn 3.0-6.0% Zn, which is an essential alloy element, together with Mg, forms clusters during aging of the manufactured tempered plate at room temperature to improve work hardening characteristics and improve the workability of the structural material.
- an aging precipitate is formed to improve the strength during the artificial aging treatment after the forming process to the structural material. If the Zn content is less than 3.0%, the strength after the artificial aging treatment is insufficient. However, if the Zn content increases and exceeds 6.0%, the grain boundary precipitate MgZn 2 increases and intergranular corrosion tends to occur, and the corrosion resistance deteriorates. Therefore, the Zn content is suppressed to be relatively small. For this reason, the lower limit of the Zn content is 3.0%, preferably 3.4%. Further, the upper limit is 6.0%, preferably 4.6%.
- Mg 2.5-4.5% Mg, which is an essential alloy element, together with Zn, forms clusters during room temperature aging of the prepared tempered plate to improve work hardening characteristics and improve formability.
- an aging precipitate is formed during the artificial aging treatment after the forming process to the structural material, thereby improving the strength.
- the Mg content in order to suppress the Zn content relatively low, conversely, the Mg content is made relatively large in order to improve moldability and strength. If the Mg content is less than 2.5% by mass, the strength is insufficient and the work hardening characteristics are deteriorated. However, if it exceeds 4.5 mass%, the rollability of the plate is lowered, and the SCC sensitivity is enhanced. Therefore, the Mg content is in the range of 2.5 to 4.5%.
- the Zn content is suppressed to be relatively low, and the Mg content is relatively increased. To do.
- the Zn content [Zn] (mass%) and the Mg content [Mg] (mass%) are preferably balanced expressions of [Zn] ⁇ ⁇ 0.3 [Mg] +4.5, preferably Satisfies the balance equation of [Zn] ⁇ ⁇ 0.5 [Mg] +5.75.
- the 0.2% proof stress of the structural material after artificial aging treatment is set to 380 MPa or more in combination with a preferable manufacturing method described later. Is possible. Further, preferably, by satisfying [Zn] ⁇ ⁇ 0.5 [Mg] +5.75, the 0.2% proof stress of the structural material after artificial aging treatment is 400 MPa in combination with a preferable manufacturing method described later. This is possible.
- the contents of Zn and Mg are [Zn] ⁇ 0.3 [Mg] +4.5, the contents of Zn and Mg are within the specified range when the Zn content is suppressed relatively low. Even in this case, or by a preferable manufacturing method to be described later, there is a possibility that the 0.2% proof stress of the structural material after the artificial aging treatment cannot be 350 MPa or more. Further, when the Zn content and the Mg content are [Zn] ⁇ 0.5 [Mg] +5.75, the 0.2% proof stress of the structural material after the artificial aging treatment cannot be set to 400 MPa or more. There is sex.
- Cu 0.05 to 0.5%
- Cu has the effect of suppressing the SCC sensitivity of the Al—Zn—Mg alloy and improving the SCC resistance. It also improves general corrosion resistance.
- the Cu content is less than 0.05%, the effect of improving SCC resistance and general corrosion resistance is small.
- the lower limit of the Cu content is 0.05%, preferably 0.10%.
- the upper limit is 0.5%, preferably 0.4%.
- Zr 0.05 to 0.3%
- Mn 0.1 to 1.5%
- Cr 0.05 to 0.3%
- Sc 0.05 to 0.3% Since the transition elements of Zr, Mn, Cr, and Sc contribute to improvement in strength by refining the crystal grains of the ingot and the final product, they are selectively contained when necessary. When any one or two or more of these are contained, if the content of Zr, Mn, Cr, or Sc is less than the lower limit, the content is insufficient and the strength is lowered. On the other hand, when the contents of Zr, Mn, Cr, and Sc exceed the respective upper limits, the elongation decreases because coarse crystals are formed.
- the content in the case of containing these is 0.05%, preferably 0.08% for the lower limit of Zr, and 0.3%, preferably 0.2% for the upper limit.
- the lower limit of Mn is 0.1%, preferably 0.2%, and the upper limit is 1.5%, preferably 1.0%.
- the lower limit of Cr is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%.
- the lower limit of Sc is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%.
- Ag and Sn have the effect of finely precipitating aging precipitates that contribute to strength improvement by artificial aging treatment after forming into a structural material and promoting high strength. Let When one or both of these are contained, if the Sn content is less than 0.001% and the Ag content is less than 0.01%, the strength improvement effect is small. On the other hand, when there is too much Sn and Ag content, various characteristics, such as rolling property and weldability, will be reduced. In addition, the strength improvement effect is saturated, and Ag is only expensive. Therefore, Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1% are set.
- Ti and B are impurities as a rolled plate, but also have the effect of refining the crystal grains of the ingot, so the upper limit of Ti is 0.2%, preferably 0.1%, and the upper limit of B is 0.05%, preferably 0.03%.
- Fe and Si are allowed to be contained without affecting the characteristics of the aluminum alloy rolled sheet according to the present invention as long as Fe: 0.5% or less and Si: 0.5% or less.
- the 7000 series aluminum alloy sheet structure of the present invention is defined by a cold-rolled sheet after tempering and aging at room temperature for 2 weeks or more. For this reason, after this cold-rolled sheet is made into a structure (tempered T4) aged at room temperature for 2 weeks or more after solution treatment and quenching treatment, this structure is observed with a transmission electron microscope of 60000 times.
- the average composition ratio (Zn / Mg) of Zn and Mg of the grain boundary precipitate (room temperature aging precipitate) is defined.
- a plate which has been aged at room temperature for 2 weeks or more after the solution treatment and quenching treatment is further subjected to (I) a heat treatment temperature of the second stage for 2 hours or more in the range of the first stage heat treatment temperature of 70 to 100 ° C.
- One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C. is performed, and this structure is observed with a transmission electron microscope of 60000 times.
- the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is defined.
- composition of grain boundary precipitates in the present invention, the average composition of Zn and Mg of grain boundary precipitates (room temperature aging precipitates) observed with a transmission electron microscope of 60000 times the texture of the tempered T4 plate
- the ratio (Zn / Mg) is in the range of 0.5 to 3.0.
- the Zn content in the grain boundary precipitate (room temperature aging precipitate) ( While reducing the Zn composition ratio), it is possible to relatively increase Mg.
- the amount of Zn consumed (unnecessarily) as this grain boundary precipitate can be reduced, and the amount of Zn solid solution in the matrix can be increased and secured.
- the amount of Zn required for the formation of aging precipitates during the subsequent artificial aging treatment can be maximized, and the balance between strength and formability and BH properties can be maximized.
- the structure of the structure by TEM is measured immediately after the tempering treatment such as solution hardening treatment in the state of the plate not aging at room temperature Roughly, as a guide, it is a plate after aging (room temperature standing) for 2 weeks or more, which is performed on the plate before forming the structure material and before the artificial aging treatment.
- the change with time in the composition ratio of the grain boundary precipitates is negligibly small even by the subsequent room temperature aging.
- composition of intragranular precipitate in order to guarantee the BH property of the manufactured cold-rolled sheet simultaneously with the grain boundary precipitate, it is applied to the plate after aging for 2 weeks or more at room temperature.
- the composition of the artificial aging precipitate is defined as the structure after the artificial aging treatment under specific conditions.
- the plate of the tempered T4 is (I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more. Or (II) One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C.
- the Zn content in the intragranular precipitate as the artificial aging precipitate is reduced. be able to.
- the Zn content (Zn composition ratio) in the intragranular precipitate can be reduced, and the amount of Zn necessary for the formation of the artificial aging precipitate (amount) can be reduced. Less is enough.
- the amount of aging precipitates contributing to strengthening during the artificial aging treatment can be maximized, and the balance between strength and formability and BH properties can be maximized.
- This intragranular precipitate has an increased composition ratio over time due to room temperature aging after the production of the plate (after tempering), so the average composition ratio (Zn) of Zn and Mg in the intragranular precipitate / Mg) for reproducibility, the same plate (the plate aged at room temperature after the tempering treatment) from which the grain boundary precipitates were measured was subjected to the artificial age hardening treatment under the specific conditions. Do as. Note that the number density of the intragranular precipitates and the average composition ratio of Zn and Mg (Zn / Mg) are naturally affected by this artificial aging treatment condition.
- the intragranular precipitate in the prior art has a high Zn content. There is no great difference from the composition. For this reason, when the Zn content as the alloy composition is lowered, the content of Zn in the intragranular precipitate (Zn composition ratio) is large, so it is necessary to form an aging precipitate (amount) during artificial aging treatment. As a result, the amount of Zn increases, and more Zn is consumed to form intragranular precipitates. For this reason, with an alloy composition having a smaller Zn content, the amount of aging precipitates contributing to strengthening during the artificial aging treatment is reduced, and the balance between strength and formability and BH properties are lowered.
- the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is less than the lower limit of 1.5 and deviates from the specified range, the Zn content itself as the composition of the plate is insufficient. This means that the intragranular precipitates, which are artificial aging precipitates, are reduced, the BH property is lowered, and the meaning itself of making a 7000 series aluminum alloy is lost.
- a structural 7000 series aluminum alloy plate with a reduced Zn content Even with a 7000 series aluminum alloy plate with a reduced Zn content, the balance between strength and ductility (formability) can be improved by the above grain boundary and grain precipitates.
- a structural 7000 series aluminum alloy having both 0.2% proof stress (BH property) of 380 MPa or more, preferably 400 MPa or more, and press forming workability, and excellent corrosion resistance such as SCC resistance. can provide a board.
- the grain boundary precipitates observed with a 60000 times TEM are lined up on the crystal grain boundaries. Observed amorphous precipitates, which can be observed with the TEM, and with TEM-EDX, the average composition ratio of Zn and Mg can be quantitatively analyzed.
- the equivalent circle diameter is as large as about 10 to 200 nm. This is a precipitate.
- the equivalent circle diameter is the diameter of a circle having the same area as an indeterminate compound, and has been widely used as a method for measuring or defining the size of a compound accurately and reproducibly. .
- the intragranular precipitates observed with a 60000-fold TEM are indeterminate precipitates scattered in the crystal grains, which can be observed with the TEM, and with TEM-EDX, the Zn and Mg
- the equivalent circle diameter is a precipitate having a size of about 1 to 50 nm that can be quantitatively analyzed.
- TEM-EDX is an X-ray spectrometer that is normally attached to the TEM used in the present invention, and is well known as an analyzer using energy dispersive X-ray spectroscopy (Energy Dispersive X-ray Spectroscopy). It is called EDX.
- This X-ray spectrometer is widely used for identification and quantitative analysis of the composition of a compound (precipitate) observed by TEM. Also in the present invention, this X-ray spectrometer is used to calculate the average composition ratio of Zn and Mg of the grain boundaries observed by the TEM and the respective precipitates in the grains.
- the average composition ratio of Zn and Mg of the grain boundaries to be defined and the precipitates in the grains is determined at arbitrary points and 10 points in the 1/4 thickness direction from the surface of the test plate to be measured. This means that 10 samples are collected and the measurement results are averaged. More specifically, with respect to a cross section perpendicular to the plate thickness direction of the test plate, a TEM (transmission electron) of 60000 times the plane parallel to the plate surface passing through an arbitrary point from the surface to 1 ⁇ 4 part in the plate thickness direction. Measure using a microscope.
- a sample is prepared by mechanically polishing a plate cross-section sample surface sampled 10 pieces from the above-mentioned site, cutting off about 0.25 mm from the plate surface by mechanical polishing, and further performing buffing to adjust the surface.
- the grain boundary to be measured in the visual field and each precipitate in the grain are specified by an automatic analyzer, and the average composition ratio of Zn and Mg in these precipitates Is measured and the average value is calculated.
- the measurement site is the sample polishing surface, and the measurement area per sample is 240 ⁇ m ⁇ 180 ⁇ m.
- the 7000 series aluminum alloy plate can be manufactured by a manufacturing method according to a normal manufacturing process. That is, an aluminum alloy hot-rolled sheet having a thickness of 1.5 to 5.0 mm is manufactured through normal manufacturing processes such as casting (DC casting or continuous casting), homogenization heat treatment, and hot rolling. The Subsequently, it is cold-rolled to obtain a cold-rolled sheet having a thickness of 3 mm or less. At this time, intermediate annealing may be selectively performed once or twice in the middle of cold rolling.
- an ordinary molten casting method such as a continuous casting method or a semi-continuous casting method (DC casting method) is appropriately selected for the aluminum alloy melt adjusted within the above-mentioned 7000-based component composition range. Cast.
- homogenization heat treatment Next, the cast aluminum alloy ingot is subjected to a homogenization heat treatment prior to hot rolling.
- the purpose of this homogenization heat treatment (soaking) is to homogenize the structure, that is, eliminate segregation in crystal grains in the ingot structure.
- the structure of the plate to be produced is defined as an average composition ratio of Zn and Mg of the precipitates in the grain boundaries and the grains observed by the TEM, and after the molding processability to the structural material. It is necessary to improve both the strength after artificial aging treatment. For this reason, it is preferable to perform the soaking process in two or two soaking steps.
- the plate structure after aging at room temperature after the tempering treatment is defined as an average composition ratio range of Zn and Mg of grain precipitates and precipitates in the grains defined in the present invention. It becomes difficult to be inside.
- Two-stage soaking means cooling after the first soaking, but it is not cooled to 200 ° C. or lower, and after stopping the cooling at a higher temperature, after maintaining at that temperature, Hot rolling is started after reheating to a high temperature.
- the two-time soaking is once cooled to a temperature of 200 ° C. or less including room temperature, reheated and maintained at that temperature for a certain period of time. Start.
- a Zn compound or a transition element compound is finely dispersed to finely affect the compound that affects the moldability to the structural material.
- solid solution of Zn, Mg, and Cu is promoted.
- the average composition ratio of Zn and Mg of the precipitates in the grain boundaries and grains observed by the TEM is obtained.
- the soaking temperature in the first stage or the first time is controlled to 400 to 450 ° C., preferably 400 to 440 ° C.
- the ingot is heated and held in this temperature range.
- the holding time of the first or first soaking may be about 1 to 8 hours.
- the second or second soaking temperature is controlled to 450 ° C. to the solidus temperature, preferably 470 ° C. to the solidus temperature.
- the solid solution of the compound can be promoted by heating and holding the ingot in this temperature range. If this soaking temperature is less than 450 ° C., sufficient dissolution of these elements cannot be obtained. On the other hand, if the solidus temperature is exceeded, partial melting occurs and the mechanical properties deteriorate, so the upper limit is made the solidus temperature or lower.
- the holding time during the second or second soaking may be about 1 to 8 hours.
- the hot rolling start temperature is selected from the range of 350 ° C. to the solidus temperature and hot rolled to obtain a hot rolled sheet having a thickness of about 2 to 7 mm. There is no need for annealing (roughening) of the hot-rolled sheet before cold rolling.
- Cold rolling In cold rolling, the hot-rolled sheet is rolled into a cold-rolled sheet (including a coil) having a desired final thickness of about 1 to 3 mm. Intermediate annealing may be performed between cold rolling passes.
- solution treatment After cold rolling, solution treatment is performed as a tempering. Thus, the average composition ratio of Zn and Mg in the grain boundary precipitates (room temperature aging precipitates) observed by the TEM is obtained.
- the solution treatment is not particularly limited and may be heating and cooling using a normal continuous heat treatment line. However, in order to obtain a sufficient solid solution amount of each element and refinement of crystal grains, the holding time is predetermined at a solution treatment temperature of 450 ° C. to a solidus temperature, preferably 480 to 550 ° C. After reaching the solution treatment temperature, it is carried out in the range of 2 to 3 seconds and 30 minutes or less.
- the average cooling (temperature decrease) rate after the solution treatment is 10 ° C./s or more in order to obtain an average composition ratio of Zn and Mg of the grain boundary precipitates (room temperature aging precipitates) observed by the TEM.
- the cooling rate is preferably as high as possible, preferably 30 ° C./s or higher, more preferably 40 ° C./s or higher.
- the average cooling (cooling) rate after solution treatment is slow, coarse grain boundary precipitates are formed, and as a result, the grain boundary precipitates (room temperature aging precipitates) Zn and Mg are observed. It is difficult to achieve an average composition ratio.
- forced cooling means such as air cooling such as a fan, water cooling means such as mist, spray, and immersion are selected or combined, or they are baked in hot water from room temperature to 100 ° C.
- the solution treatment is basically only one time, but when the room temperature age hardening has progressed too much, the solution treatment and the restoration treatment are made the above-mentioned preferable conditions in order to ensure the moldability to the automobile member. It may be applied again, and this excessive room temperature age hardening may be canceled once.
- the aluminum alloy plate of the present invention is molded into an automobile member as a material and assembled as an automobile member.
- artificial aging treatment is separately performed to obtain an automobile member or an automobile body.
- Artificial age hardening treatment The 7000 series aluminum alloy plate of the present invention is observed by the TEM by an artificial age hardening treatment (hereinafter also simply referred to as artificial aging treatment or aging treatment) after forming into a structural material.
- the average composition ratio of Zn and Mg in the aging precipitate) is set to 380 MPa or more, preferably 400 MPa or more at a desired strength and 0.2% proof stress as a structural material such as an automobile member.
- the time point at which this artificial aging treatment is performed is preferably after the forming processing of the material 7000 series aluminum alloy plate to the automobile member. This is because the 7000 series aluminum alloy plate after the artificial aging treatment has high strength but has low formability, and may not be formed depending on the complexity of the shape of the automobile member.
- the temperature and time conditions of this artificial aging treatment are determined within the range of general artificial aging conditions (T6, T7) from the desired strength, the strength of the 7000 series aluminum alloy plate of the material, or the progress of room temperature aging. Is done.
- T6, T7 general artificial aging conditions
- the aging treatment at 100 to 150 ° C. is performed for 12 to 36 hours (including the overaging region) in the case of one-stage aging treatment.
- the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or longer
- the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for five hours or longer (overaging region). Select from).
- the strength after BH is used as the structural material, particularly as the average composition ratio of Zn and Mg in the intragranular precipitate (artificial aging precipitate) observed by the TEM.
- This condition means that the heating rate during the artificial aging treatment in the one-stage artificial aging process or the heating rate during the first artificial aging treatment in the two-stage artificial aging treatment is 30 ° C./min or less. It is to carry out at the slowest possible heating rate.
- the second stage temperature rise rate does not affect the strength after BH, and an efficient temperature rise rate of 30 ° C./min or more is selected.
- the second stage reheating can be performed after holding at the first stage heating temperature, after cooling to room temperature and then reheating, or by continuously reheating from the held temperature. There is no difference in the impact on either.
- the conditions of the artificial age hardening treatment in the average composition ratio (Zn / Mg) of Zn and Mg of the intragranular precipitates defined as preferable conditions in the present invention are 90 ° C. at a temperature rising rate of 30 ° C./min. It is set as a two-stage specific condition of heating to 140 ° C. at a heating rate of 30 ° C./min and holding for 8 hours. This is for the purpose of correlating the average composition ratio of Zn and Mg of intragranular precipitates produced in the actual artificial aging treatment after forming the material 7000 series aluminum alloy plate into an automobile member. It is.
- the conditions of the actual artificial aging treatment after forming the material 7000 series aluminum alloy plate on the automobile member are variously different.
- each heating rate is set to 30 ° C./min or less
- the artificial aging treatment conditions are within the above preferred range, the strength
- the temperature increase rate of 30 ° C./min under the condition of artificial age hardening in the average composition ratio (Zn / Mg) of the intragranular precipitates defined in the present invention is 380 MPa, which is necessary for the structural material.
- the average composition ratio (Zn / Mg) of Zn and Mg of the precipitates in the grain boundaries and grains within the plate is as shown in Tables 2 and 3 together with the component composition shown in Table 1
- the average cooling rate after the solution treatment of the cold rolled sheet was variously controlled.
- a 7000 series aluminum alloy molten metal having each component composition shown in Table 1 below was DC cast to obtain an ingot of 45 mm thickness ⁇ 220 mm width ⁇ 145 mm length.
- the ingot was subjected to two-stage soaking or twice soaking under the conditions shown in Table 2.
- the second stage soaking is cooled to 250 ° C., once the cooling is stopped at that temperature, reheated and held at the second stage soaking temperature, and cooled to the hot rolling start temperature.
- the hot rolling was started.
- the second soaking was once cooled to room temperature, reheated and held at the second soaking temperature, cooled to the hot rolling start temperature, and then started hot rolling.
- the soaking process of only one time in Table 2 does not perform the second reheating after cooling once, and keeps the soaking temperature and time as usual, and then cools to the hot rolling start temperature and performs hot rolling. Started.
- hot rolling was performed at a starting temperature shown in Table 2 to produce a hot rolled sheet having a thickness of 5 mm.
- This hot-rolled sheet was cold-rolled to 2 mmt without subjecting it to any roughening treatment.
- the cold-rolled sheet is subjected to a solution treatment at 500 ° C. for 1 minute in common with each example, and after this solution treatment, the method of forced air cooling is changed, and the average cooling rate is changed to various temperatures to cool to room temperature.
- a tempered material was obtained.
- the aluminum alloy plate after solution treatment was sampled from a plate aged at room temperature for 2 weeks in common with each example, and an average composition ratio of Zn and Mg of the precipitates at the grain boundaries was collected. Measurement of (Zn / Mg), measurement of work hardening index n value, mechanical properties such as strength and elongation were investigated as follows.
- the artificial age-hardening treatment after forming the automobile member was simulated, and the aluminum alloy sheet after room temperature aging for the above two weeks was treated as T6 treatment, and further the first stage temperature increase rate shown in Tables 2 and 3 Then, after holding at the aging temperature for 3 hours, the artificial age hardening treatment is performed in two stages in which it is continuously reheated from the held temperature, heated to 140 ° C. at a heating rate of 30 ° C./min and held for 8 hours. Went.
- Invention Example 18 in Table 2 was performed under the condition that the first stage was heated to 90 ° C. at a temperature increase rate of 30 ° C./min and held for 3 hours, and then the second stage was 30 ° C. / The heating rate was 1 minute, and the heating was performed up to 130 ° C. and held for 12 hours.
- Inventive example 19 in Table 2 was an artificial aging treatment with only one stage, and the temperature elevation rate was 30 ° C./min. The temperature was raised to 120 ° C. and maintained for 24 hours.
- a plate-shaped test piece is taken from the central part of the aluminum alloy plate after the artificial age hardening treatment, and the average composition ratio (Zn / Mg) of Zn and Mg of each precipitate in the grains, mechanical properties and corrosion resistance are also obtained.
- the investigation was conducted as follows. These results are shown in Tables 2 and 3, respectively.
- the work hardening index n value was measured by performing a room temperature tensile test in the direction perpendicular to the rolling direction, using the plate-like test piece after the artificial age hardening treatment as a JIS No. 5 tensile test piece (distance between gauge points 50 mm). Then, the true stress and true strain are calculated from the end point of yield elongation, plotted on a logarithmic scale with the horizontal axis being strain and the vertical axis being stress, and the gradient of the straight line represented by the measurement point is 10% or 15% of nominal strain. The n value (10 to 15%) was calculated from the two points.
- a current having a current density of 1 mA / cm 2 was allowed to flow for 24 hours in a state immersed in an aqueous sodium chloride solution (5% by mass), and then the sample was pulled up, and then the cross section of the test piece was cut and polished.
- the magnification was x100, and a corrosion depth of 200 ⁇ m or less was evaluated as “ ⁇ ” as minor corrosion. Moreover, the case where it exceeded 200 micrometers was evaluated as "x" as big corrosion.
- Invention Examples 1 to 19 are within the composition range of the aluminum alloy of the present invention, and are manufactured within the range of the preferable manufacturing conditions described above.
- (Zn / Mg) is in the range of 0.5 to 3.0.
- the average composition ratio (Zn / Mg) with Mg is in the range of 1.5 to 3.5, which satisfies the structure provision of the present invention.
- Comparative Examples 20 to 32 in Table 3 have an alloy composition of 17 to 29 as shown in Table 1, which is outside the scope of the present invention.
- the alloy compositions are numbers 17 and 18 in Table 1, and [Zn] and [Mg] are within the specified ranges, respectively, but are balanced expressions of Zn and Mg. Both [Zn] ⁇ ⁇ 0.3 [Mg] +4.5 and [Zn] ⁇ ⁇ 0.5 [Mg] +5.75 are not satisfied. For this reason, although it is manufactured within preferable manufacturing conditions, the composition ratio of precipitates is not satisfied, and the work hardening index n value (10 to 15%) after room temperature aging is 0.21 to 0.22 level. Even if the 0.2% yield strength after the age hardening treatment is high, it is too low at about 329 MPa, and it does not have both moldability and strength.
- the alloy compositions are 19 to 21 with the numbers in Table 1, and Mg is too small beyond the lower limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value is 0.21 level, even if the 0.2% proof stress after the artificial age hardening treatment is high, it is too low at about 353 MPa, and it does not have both moldability and strength.
- Comparative Examples 25 to 28 have an alloy composition of 22 to 25 as shown in Table 1, and Mg is too much outside the upper limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value (10-15%) is 0.22 to 0.23 level, even if the 0.2% proof stress after artificial age hardening is high, it is too low at around 369 MPa, and it does not have both moldability and strength. .
- Comparative Examples 29 and 30 have alloy compositions of numbers 26 and 27 in Table 1, and Zn is too much outside the upper limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value (10-15%) is 0.22 to 0.23 level, even if the 0.2% yield strength after artificial age hardening is high, it is too low at around 362 MPa, and it does not have both moldability and strength. . Moreover, corrosion resistance is also inferior.
- Comparative Example 31 has an alloy composition of 28 as shown in Table 1, and Cu is out of the lower limit. For this reason, the balance formula of Zn and Mg is satisfied, manufactured within preferable manufacturing conditions, satisfies the precipitate composition ratio, and has a work hardening index n value (10 to 15%) after aging at room temperature of 0.23. In terms of level, the 0.2% proof stress after the artificial age hardening treatment is also at the 448 MPa level, and it has both moldability and strength. However, it is fatally inferior in corrosion resistance.
- Comparative Example 32 has an alloy composition of 29 in Table 1 and Cu is out of the upper limit. For this reason, the balance formula of Zn and Mg is satisfied, and it is manufactured within preferable manufacturing conditions and satisfies the precipitate composition ratio, but the work hardening index n value (10 to 15%) after aging at room temperature is 0.00. It is as low as 209, and the 0.2% proof stress after artificial age hardening is at the level of 456 MPa, but it does not have both moldability and strength.
- Comparative Examples 33 to 37 in Table 3 are manufactured out of the preferable manufacturing condition range, although the invention example aluminum alloy of Alloy No. 1 in Table 1 is used.
- the first soaking temperature is too low.
- Comparative Example 34 the second soaking temperature is too low.
- Comparative Example 35 the average cooling rate after the solution treatment is too slow.
- Comparative Examples 36 and 37 are only one-time heat treatment.
- the comparative example in which these soaking conditions deviate from the preferred range does not satisfy the compositional ratio Zn / Mg of grain boundary precipitates or the composition ratio Zn / Mg of intragranular precipitates, and work hardening after aging at room temperature.
- the index n value (10 to 15%) is less than 0.22 and the ductility and molding processability to structural materials are inferior, or the 0.2% proof stress after artificial age hardening is less than 340 MPa. It does not have both workability and strength.
- the present invention can provide a 7000 series aluminum alloy plate for automobile members having strength, formability, and corrosion resistance even after aging at room temperature. Therefore, the present invention is also suitable for automobile structural materials such as frames and pillars that contribute to weight reduction of the vehicle body, and structural materials for other uses.
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Abstract
In the present invention, a 7000-series aluminum alloy sheet of specific composition maintains high strength with a balance between the Mg content and Zn content while the Zn content is controlled. The sheet, which is manufactured using ordinary methods, is imparted with the corrosion resistance, moldability, and high strength demanded of a structural material, by controlling the average compositional ratio of Zn and Mg in an grain boundary precipitate when the manufactured sheet is aged at room temperature and the average compositional ratio of Zn and Mg in an intragranular precipitate of the sheet after an artificial age-hardening treatment is further carried out thereon.
Description
本発明は加工性を向上させ、耐食性にも優れた高強度な構造材用アルミニウム合金板に関するものである。本発明のアルミニウム合金板とは、圧延板であって、圧延によって製造された板を溶体化および焼入れ処理後に2週間以上室温時効した後の板であって、構造材への成形加工前および人工時効硬化処理前の板のことを言う。また、本発明でいう室温時効させた板の組織とは、前記溶体化および焼入れ処理後に2週間以上室温時効した後の板の組織を言う。
The present invention relates to a high-strength aluminum alloy plate for a structural material that has improved workability and excellent corrosion resistance. The aluminum alloy plate of the present invention is a rolled plate, which is a plate obtained by subjecting a plate produced by rolling to aging at room temperature for 2 weeks or more after solution treatment and quenching treatment, before forming into a structural material and artificial This refers to the plate before age hardening. The structure of the plate aged at room temperature in the present invention refers to the structure of the plate after aging at room temperature for 2 weeks or more after the solution treatment and quenching treatment.
近年、地球環境などへの配慮から、自動車車体の軽量化の社会的要求はますます高まってきている。かかる要求に答えるべく、自動車車体のうち、パネル(フード、ドア、ルーフなどのアウタパネル、インナパネル)や、バンパリーンフォース(バンパーR/F)やドアビームなどの補強材などを、部分的に鋼板等の鉄鋼材料に代えて、アルミニウム合金材料を適用することが行われている。
In recent years, due to consideration for the global environment, social demands for reducing the weight of automobile bodies are increasing. In order to respond to such demands, panels (outer panels such as hoods, doors and roofs, inner panels), bumper reinforcements (bumper R / F), door beams, and other reinforcing materials are partly made of steel, etc. Instead of the steel material, an aluminum alloy material is applied.
ただ、自動車車体のより軽量化のためには、自動車部材のうちでも特に軽量化に寄与する、フレーム、ピラーなどの自動車構造部材にも、アルミニウム合金材料の適用を拡大することが必要となる。ただ、これら自動車構造部材は、要求される0.2%耐力が350MPa以上であるなど、前記自動車パネルに比べて、高強度化が必要である。この点で、前記自動車パネルに使用されている、成形性や強度、耐食性、そして低合金組成でリサイクル性に優れた、JIS乃至AA6000系アルミニウム合金板では、組成や調質(溶体化処理および焼入れ処理、更には人工時効硬化処理)を制御しても、前記高強度化を達成するにはほど遠い。
However, in order to reduce the weight of automobile bodies, it is necessary to expand the application of aluminum alloy materials to automobile structural members such as frames and pillars that contribute particularly to weight reduction among automobile parts. However, these automobile structural members need to have higher strength than the above-mentioned automobile panels, for example, the required 0.2% proof stress is 350 MPa or more. In this respect, the composition and tempering (solution treatment and quenching) of the JIS to AA6000 series aluminum alloy plates, which are used in the above-mentioned automobile panels, are excellent in formability, strength, corrosion resistance, low alloy composition and recyclability. Control of the treatment, and further, the artificial age hardening treatment, is far from achieving the high strength.
したがって、このような高強度な自動車構造部材には、同じような高強度が要求される前記補強材として使用されているJIS乃至AA7000系アルミニウム合金板を用いる必要がある。しかし、Al-Zn-Mg系アルミニウム合金である、7000系アルミニウム合金は、一般耐食性が劣る。また、Zn及びMgからなる析出物MgZn2を高密度に分布させることで高強度を達成する合金であるため、応力腐食割れ(以下、SCC)を起こす危険性がある。これを防止するため、やむを得ず過時効処理を行って、0.2%耐力が300MPa程度で使用されているのが実情であり、高強度合金としての特徴が薄れている。
Therefore, it is necessary to use a JIS or AA7000 series aluminum alloy plate that is used as the reinforcing material requiring the same high strength for such a high-strength automobile structural member. However, the 7000 series aluminum alloy, which is an Al—Zn—Mg series aluminum alloy, is inferior in general corrosion resistance. Moreover, since it is an alloy which achieves high strength by distributing precipitates MgZn 2 consisting of Zn and Mg at high density, there is a risk of causing stress corrosion cracking (hereinafter referred to as SCC). In order to prevent this, it is inevitable that an over-aging treatment is performed and the 0.2% proof stress is used at about 300 MPa, and the characteristics as a high-strength alloy are weakened.
このため、強度と耐SCC性の両方に優れた7000系アルミニウム合金押出材の組成制御や、析出物などの組織制御が、従来から種々提案されている。これに対して、7000系アルミニウム合金板における、従来の組成制御や析出物などの組織制御例は、板での実用化の少なさに応じて、きわめて少ない。
For this reason, various composition control of 7000 series aluminum alloy extruded material excellent in both strength and SCC resistance and structure control of precipitates have been conventionally proposed. On the other hand, there are very few examples of conventional structure control such as composition control and precipitates in a 7000 series aluminum alloy plate according to the small practical use of the plate.
このうち、特許文献1には、溶湯を急冷凝固後に冷間圧延し、更に人工時効硬化処理後の7000系アルミニウム合金板の結晶粒内における晶析出物について、400倍の光学顕微鏡での測定によって、大きさ(面積が等価な円相当径に換算)を3.0μm以下とし、平均面積分率を4.5%以下として、強度や伸びを向上させている。
Among these, in Patent Document 1, the molten metal is cold-rolled after rapid solidification, and further, crystal precipitates in the crystal grains of the 7000 series aluminum alloy plate after artificial age hardening treatment are measured by a 400 times optical microscope. , The size (converted to equivalent circle equivalent diameter) is 3.0 μm or less, and the average area fraction is 4.5% or less to improve strength and elongation.
また、特許文献2、3では、構造材用の7000系板の高強度化、高耐SCC性化を図るために、鋳塊を鍛造後に、温間加工域にて繰り返して圧延して、組織を細かくしている。これは、組織を細かくすることによって、耐SCC性低下の原因となる粒界と粒内との電位差の要因となる、方位差が20°以上の大傾角粒界を抑制して、3~10°の小傾角粒界が25%以上である集合組織を得るためである。ただ、このような温間圧延の繰り返しは、常法の熱間圧延、冷間圧延の方式では、このような小傾角粒界が25%以上である集合組織を得ることができないために行われている。したがって、常法とは大きく工程が異なるために、板をつくるために実用的な方法とは言い難い。
Further, in Patent Documents 2 and 3, in order to increase the strength and SCC resistance of a 7000 series plate for a structural material, the ingot is repeatedly rolled in a warm working region after forging, and the structure Is fine. This is because, by making the structure finer, a large tilt grain boundary having an orientation difference of 20 ° or more, which causes a potential difference between the grain boundary and the grain boundary, which causes a decrease in SCC resistance, is suppressed. This is to obtain a texture having a small angle grain boundary of 25 ° or more. However, such warm rolling is repeated because the conventional hot rolling and cold rolling methods cannot obtain a texture in which such a low-angle grain boundary is 25% or more. ing. Therefore, since the process is greatly different from the conventional method, it is difficult to say that it is a practical method for producing a plate.
このように、強度と耐SCC性の両方に優れた7000系アルミニウム合金の組成制御や析出物、あるいは集合組織などの組織制御などの提案は、従来から押出材の分野については種々されている。ただ、鋳塊を均熱処理後に熱間圧延および冷間圧延するような、常法によって製造される圧延板については、クラッド板、急冷凝固法、温間圧延などの特殊な圧延あるいは製法以外には、あまり提案がないのが実状である。
As described above, proposals such as composition control of 7000 series aluminum alloy excellent in both strength and SCC resistance and structure control of precipitates or textures have been conventionally various in the field of extruded materials. However, for rolled sheets manufactured by conventional methods, such as hot rolling and cold rolling after inhomogeneous heat treatment of the ingot, other than special rolling or manufacturing methods such as clad plate, rapid solidification method, warm rolling, etc. The fact is that there are not many proposals.
そして、押出材は、前記圧延板とは、その熱間加工工程などの製造過程が全く異なり、出来上がる結晶粒や析出物などの組織も、例えば結晶粒が押出方向に伸長した繊維状であるなど、結晶粒が基本的に等軸粒の圧延板とは大きく異なる。このため、前記押出材での組成制御や析出物などの組織制御などの提案が、7000系アルミニウム合金板にも、そして、この7000系アルミニウム合金板からなる自動車構造部材にも、そのまま適用でき、強度と耐SCC性の両方の向上に果たして有効であるかどうかは不明である。すなわち、実際に確認しない限りは、あくまで予想の域を出ない。
And, the extruded material is completely different from the rolled plate in its manufacturing process such as a hot working process, and the resulting structure of crystal grains and precipitates is, for example, a fibrous form in which the crystal grains are elongated in the extrusion direction. , The crystal grains are basically different from a rolled plate having equiaxed grains. For this reason, proposals such as composition control in the extruded material and structure control of precipitates can be applied to 7000 series aluminum alloy plates and also to automobile structural members made of this 7000 series aluminum alloy plates. It is unclear whether it is effective in improving both strength and SCC resistance. In other words, unless it is actually confirmed, it does not leave the expected range.
したがって、前記常法によって製造される7000系アルミニウム合金板の、強度と耐SCC性の両方に優れた組織制御技術については、未だ有効な手段がなく、不明な点が多く解明の余地があるというのが現状である。また、一般耐食性に関してはZn添加による電位の卑化が関与しているため、強度と耐食性の観点からZn添加量を下げる必要がある。しかしながら、Zn含有量を下げると耐食性は改善するものの、前記構造部材での必要特性である曲げ性などの成形加工性は向上する反面、強度が低下するという、高強度化と矛盾して技術的に困難な課題となる。
Therefore, there is still no effective means for the structure control technology excellent in both strength and SCC resistance of the 7000 series aluminum alloy plate produced by the above-mentioned conventional method, and there are many unclear points and room for clarification. is the current situation. Further, regarding the general corrosion resistance, since the potential reduction due to the addition of Zn is involved, it is necessary to reduce the Zn addition amount from the viewpoint of strength and corrosion resistance. However, although the corrosion resistance is improved when the Zn content is reduced, the formability such as bendability, which is a necessary characteristic of the structural member, is improved, while the strength is lowered and contradictory to the increase in strength. It will be a difficult task.
以上述べた課題に鑑み、本発明の目的は、前記常法によって製造される圧延板として、室温時効後であっても、強度と成形加工性とを兼備し、耐食性にも優れた、自動車部材などの構造材用7000系アルミニウム合金板を提供することである。
In view of the above-described problems, the object of the present invention is to provide an automobile member having both strength and formability and excellent corrosion resistance even after aging at room temperature as a rolled plate produced by the conventional method. It is to provide a 7000 series aluminum alloy plate for structural materials.
この目的を達成するために、本発明構造材用アルミニウム合金板の要旨は、質量%で、Zn:3.0~6.0%、Mg:2.5~4.5%、Cu:0.05~0.5%を各々含み、かつZnの含有量[Zn]とMgの含有量[Mg]とが[Zn]≧-0.3[Mg]+4.5を満足する関係にあり、残部がAlおよび不可避的不純物からなる組成のAl-Zn-Mg系アルミニウム合金板であって、この板を溶体化および焼入れ処理後に室温時効させた組織において、60000倍の透過型電子顕微鏡にて観察される粒界析出物のZnとMgとの平均組成比(Zn/Mg)が0.5~3.0の範囲であり、前記溶体化および焼入れ処理後に室温時効させた板を、
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
いずれか一方を行った後の板の組織において、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であることとする。 In order to achieve this object, the gist of the aluminum alloy sheet for structural material of the present invention is, in mass%, Zn: 3.0 to 6.0%, Mg: 2.5 to 4.5%, Cu: 0.00. The Zn content [Zn] and the Mg content [Mg] satisfy [Zn] ≧ −0.3 [Mg] +4.5, and the balance Is an Al—Zn—Mg-based aluminum alloy plate having a composition composed of Al and inevitable impurities, and is observed with a transmission electron microscope of 60000 times in a structure in which this plate is aged at room temperature after solution treatment and quenching treatment. The average composition ratio (Zn / Mg) of Zn and Mg in the grain boundary precipitates is 0.5 to 3.0, and a plate aged at room temperature after the solution treatment and quenching treatment,
(I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more.
Or
(II) Particles observed with a transmission electron microscope at 60000 times in the structure of the plate after one of the one-stage artificial aging treatments for 12 to 36 hours at a heat treatment temperature of 100 to 150 ° C. The average composition ratio (Zn / Mg) of Zn and Mg in the inner precipitate is in the range of 1.5 to 3.5.
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
いずれか一方を行った後の板の組織において、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であることとする。 In order to achieve this object, the gist of the aluminum alloy sheet for structural material of the present invention is, in mass%, Zn: 3.0 to 6.0%, Mg: 2.5 to 4.5%, Cu: 0.00. The Zn content [Zn] and the Mg content [Mg] satisfy [Zn] ≧ −0.3 [Mg] +4.5, and the balance Is an Al—Zn—Mg-based aluminum alloy plate having a composition composed of Al and inevitable impurities, and is observed with a transmission electron microscope of 60000 times in a structure in which this plate is aged at room temperature after solution treatment and quenching treatment. The average composition ratio (Zn / Mg) of Zn and Mg in the grain boundary precipitates is 0.5 to 3.0, and a plate aged at room temperature after the solution treatment and quenching treatment,
(I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more.
Or
(II) Particles observed with a transmission electron microscope at 60000 times in the structure of the plate after one of the one-stage artificial aging treatments for 12 to 36 hours at a heat treatment temperature of 100 to 150 ° C. The average composition ratio (Zn / Mg) of Zn and Mg in the inner precipitate is in the range of 1.5 to 3.5.
本発明者らは、耐食性向上のためにZn含有量を抑える一方で、強度や成形性を確保するためにMg含有量を増やした組成の7000系アルミニウム合金板につき、室温時効した板組織の粒界と粒内の析出物に注目し、これら析出物の組成が特性に及ぼす影響について解析した。
The present inventors reduced the Zn content for improving the corrosion resistance, while using a 7000 series aluminum alloy plate having a composition in which the Mg content was increased to ensure strength and formability, the grains of the plate structure aged at room temperature. Focusing on the precipitates in the boundaries and grains, the effect of the composition of these precipitates on the properties was analyzed.
その結果、製造後の板の室温時効により生成する粒界析出物中のZn含有量(Zn組成比)を減らすと、この粒界析出物に(無駄に)消費されるZn量を低下させ、マトリックス中のZn固溶量を確保できることを知見した。そして、このように、マトリックス中のZn固溶量を確保できれば、合金組成としてのZn含有量を下げたとしても、その後の人工時効処理時の人工時効析出物(粒内析出物)の形成に必要なZn量を最大化させられ、強度と成形性のバランスやBH性を最大化できることにつながる。
As a result, reducing the Zn content (Zn composition ratio) in the grain boundary precipitates produced by room temperature aging of the manufactured plate, the Zn amount consumed (uselessly) in the grain boundary precipitates is reduced, It was found that the Zn solid solution amount in the matrix can be secured. And if the amount of Zn solid solution in the matrix can be secured in this way, even if the Zn content as the alloy composition is lowered, the formation of artificial aging precipitates (intragranular precipitates) during the subsequent artificial aging treatment The necessary amount of Zn can be maximized, and the balance between strength and formability and BH properties can be maximized.
また、人工時効処理時に形成される時効析出物である、粒内析出物中のZn含有量(Zn組成比)を減らすと、人工時効処理時に生成する粒内析出物(量)の形成に必要なZn量が少なくて済むことを知見した。このため、合金組成としてのZn含有量を下げても、人工時効処理時の、強化に寄与する時効析出物の析出量を最大化させられ、強度と成形性のバランスやBH性を最大化することができる。
In addition, reducing the Zn content (Zn composition ratio) in intragranular precipitates, which are aging precipitates formed during artificial aging treatment, is necessary for the formation of intragranular precipitates (amount) generated during artificial aging treatment It has been found that a small amount of Zn is sufficient. For this reason, even if the Zn content as the alloy composition is lowered, the amount of aging precipitates contributing to strengthening during the artificial aging treatment can be maximized, and the balance between strength and formability and BH properties are maximized. be able to.
このような析出物の組成制御によって、本発明は、Zn含有量を抑えた7000系アルミニウム合金板であっても、強度と延性(成形性)のバランスやBH性を向上させることができ、常法によって製造される圧延板として、強度と成形性(以下、成形加工性あるいは加工性とも言う)とを兼備し、耐SCC性などの耐食性にも優れた構造用7000系アルミニウム合金板を提供できる。
By controlling the composition of such precipitates, the present invention can improve the balance between strength and ductility (formability) and BH properties, even for a 7000 series aluminum alloy plate with a reduced Zn content. As a rolled plate manufactured by the method, a structural 7000 series aluminum alloy plate having both strength and formability (hereinafter also referred to as formability or workability) and excellent corrosion resistance such as SCC resistance can be provided. .
本発明では、このように室温時効により生成する粒界析出物組成を規定するため、前記TEMによる組織の測定を、前記調質処理直後の室温時効していない板の状態ではなく、目安として2週間以上室温時効(室温放置)した後の板であって、構造材への成形加工前および人工時効硬化処理前の板に対して行う。
In the present invention, in order to define the composition of the grain boundary precipitates generated by room temperature aging in this way, the measurement of the structure by the TEM is not a state of a plate that has not been aged at room temperature immediately after the tempering treatment, but as a guideline. This is a plate after aging at room temperature (room temperature standing) for more than a week, and is performed on the plate before forming into a structural material and before artificial age hardening treatment.
以下に、本発明の実施の形態につき、要件ごとに具体的に説明する。
Hereinafter, the embodiment of the present invention will be specifically described for each requirement.
本発明で言うアルミニウム合金板とは、圧延によって製造された板であって、鋳塊を均熱処理後に熱間圧延され、更に冷間圧延されて冷延板とされ、更に溶体化および焼入れ処理などの調質処理(質別記号でT4)が施された、常法によって製造された7000系アルミニウム合金板のことを言う。言い換えると、前記特許文献2,3の鋳塊を鍛造した上で温間圧延を繰り返すような特殊な圧延方法や、双ロールなどの熱延を省いた薄板連鋳法などにより、製造される板を含まない。
The aluminum alloy plate referred to in the present invention is a plate produced by rolling, and the ingot is hot-rolled after soaking, further cold-rolled into a cold-rolled plate, and further subjected to solution treatment and quenching treatment, etc. The 7000 series aluminum alloy plate manufactured by the usual method to which the tempering process (T4 by the symbol according to quality) was performed. In other words, a plate produced by a special rolling method in which the ingots of Patent Documents 2 and 3 are forged and then repeated warm rolling, or a thin plate continuous casting method in which hot rolling such as twin rolls is omitted. Not included.
更に、本発明で言うアルミニウム合金板とは、上記のように製造された7000系アルミニウム合金板の室温時効した組織を規定し、かつ素材アルミニウム合金板として用途の構造材に成形加工されるものである。このため、上記のように製造された板を、室温時効(室温放置)した後の板であって、用途としての構造材への成形加工前および人工時効硬化処理前の板のことを言う。以下、人工時効硬化を単に人工時効、人工時効硬化処理を単に人工時効処理とも言う。
Furthermore, the aluminum alloy plate referred to in the present invention defines the room temperature aged structure of the 7000 series aluminum alloy plate produced as described above, and is formed into a structural material for use as a material aluminum alloy plate. is there. For this reason, it refers to a plate after the plate manufactured as described above is aged at room temperature (room temperature standing), and before being formed into a structural material as an application and before artificial age hardening treatment. Hereinafter, artificial age hardening is also simply referred to as artificial ageing, and artificial age hardening is simply referred to as artificial ageing.
(アルミニウム合金組成)
先ず、本発明アルミニウム合金板の化学成分組成について、各元素の限定理由を含めて、以下に説明する。なお、各元素の含有量の%表示は全て質量%の意味である。 (Aluminum alloy composition)
First, the chemical component composition of the aluminum alloy sheet of the present invention will be described below, including reasons for limiting each element. In addition,% display of content of each element means the mass% altogether.
先ず、本発明アルミニウム合金板の化学成分組成について、各元素の限定理由を含めて、以下に説明する。なお、各元素の含有量の%表示は全て質量%の意味である。 (Aluminum alloy composition)
First, the chemical component composition of the aluminum alloy sheet of the present invention will be described below, including reasons for limiting each element. In addition,% display of content of each element means the mass% altogether.
本発明アルミニウム合金板の化学成分組成は、常法によって製造される圧延板として、本発明で意図する自動車部材などの構造材用としての要求特性である、強度と成形加工性とを兼備し、耐食性も満足させる前提条件となる。このため、本発明におけるAl-Zn-Mg-Cu系の7000系アルミニウム合金組成は、耐食性向上のためにZn含有量を抑える一方で、強度を確保するためにMg含有量を増やした組成とする。
The chemical composition of the aluminum alloy sheet of the present invention combines strength and formability, which are required characteristics for structural materials such as automobile members intended in the present invention, as a rolled sheet produced by a conventional method. It is a prerequisite for satisfying corrosion resistance. For this reason, the Al-Zn-Mg-Cu-based 7000 series aluminum alloy composition in the present invention is a composition in which the Mg content is increased in order to secure strength while suppressing the Zn content in order to improve the corrosion resistance. .
この観点から、本発明アルミニウム合金板の化学成分組成は、質量%で、Zn:3.0~6.0%、Mg:2.5~4.5%、Cu:0.05~0.5%を各々含み、かつZnの含有量[Zn]とMgの含有量[Mg]とが[Zn]≧-0.3[Mg]+4.5を満足する関係にあり、残部がAlおよび不可避的不純物からなるものとする。この組成に、更に加えて、遷移元素として、Zr:0.05~0.3%、Mn:0.1~1.5%、Cr:0.05~0.3%、Sc:0.05~0.3%の1種又は2種以上を選択的に含んでも良い。また、これらの遷移元素に加えて、あるいは代えて、更に、Ag:0.01~0.2%、Sn:0.001~0.1%の1種又は2種を選択的に含んでも良い。
From this point of view, the chemical composition of the aluminum alloy sheet of the present invention is, by mass, Zn: 3.0 to 6.0%, Mg: 2.5 to 4.5%, Cu: 0.05 to 0.5. %, And the Zn content [Zn] and the Mg content [Mg] satisfy [Zn] ≧ −0.3 [Mg] +4.5, with the balance being Al and inevitable It shall consist of impurities. In addition to this composition, as transition elements, Zr: 0.05 to 0.3%, Mn: 0.1 to 1.5%, Cr: 0.05 to 0.3%, Sc: 0.05 One type or two or more types of up to 0.3% may be selectively included. In addition to or instead of these transition elements, one or two of Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1% may be selectively included. .
Zn:3.0~6.0%
必須の合金元素であるZnは、Mgとともに、製造された調質後の板の室温時効時にクラスタを形成して加工硬化特性を向上させ、構造材への成形加工性を向上させる。また、構造材への成形加工後の人工時効処理時に、時効析出物を形成して強度を向上させる。Zn含有量が3.0%未満では人工時効処理後の強度が不足する。但し、Zn含有量が多くなって6.0%を超えると、粒界析出物MgZn2が増えて粒界腐食が起こりやすくなり、耐食性が劣化する。従って、Zn含有量は比較的少なめに抑制する。このため、Zn含有量の下限は3.0%、好ましくは3.4%である。また、上限は6.0%、好ましくは4.6%である。 Zn: 3.0-6.0%
Zn, which is an essential alloy element, together with Mg, forms clusters during aging of the manufactured tempered plate at room temperature to improve work hardening characteristics and improve the workability of the structural material. In addition, an aging precipitate is formed to improve the strength during the artificial aging treatment after the forming process to the structural material. If the Zn content is less than 3.0%, the strength after the artificial aging treatment is insufficient. However, if the Zn content increases and exceeds 6.0%, the grain boundary precipitate MgZn 2 increases and intergranular corrosion tends to occur, and the corrosion resistance deteriorates. Therefore, the Zn content is suppressed to be relatively small. For this reason, the lower limit of the Zn content is 3.0%, preferably 3.4%. Further, the upper limit is 6.0%, preferably 4.6%.
必須の合金元素であるZnは、Mgとともに、製造された調質後の板の室温時効時にクラスタを形成して加工硬化特性を向上させ、構造材への成形加工性を向上させる。また、構造材への成形加工後の人工時効処理時に、時効析出物を形成して強度を向上させる。Zn含有量が3.0%未満では人工時効処理後の強度が不足する。但し、Zn含有量が多くなって6.0%を超えると、粒界析出物MgZn2が増えて粒界腐食が起こりやすくなり、耐食性が劣化する。従って、Zn含有量は比較的少なめに抑制する。このため、Zn含有量の下限は3.0%、好ましくは3.4%である。また、上限は6.0%、好ましくは4.6%である。 Zn: 3.0-6.0%
Zn, which is an essential alloy element, together with Mg, forms clusters during aging of the manufactured tempered plate at room temperature to improve work hardening characteristics and improve the workability of the structural material. In addition, an aging precipitate is formed to improve the strength during the artificial aging treatment after the forming process to the structural material. If the Zn content is less than 3.0%, the strength after the artificial aging treatment is insufficient. However, if the Zn content increases and exceeds 6.0%, the grain boundary precipitate MgZn 2 increases and intergranular corrosion tends to occur, and the corrosion resistance deteriorates. Therefore, the Zn content is suppressed to be relatively small. For this reason, the lower limit of the Zn content is 3.0%, preferably 3.4%. Further, the upper limit is 6.0%, preferably 4.6%.
Mg:2.5~4.5%
必須の合金元素であるMgは、Znとともに、製造された調質後の板の室温時効時にクラスタを形成して加工硬化特性を向上させ、成形性を向上させる。また、構造材への成形加工後の人工時効処理時に時効析出物を形成して強度を向上させる。本発明では、Zn含有量を比較的低めに抑制するため、逆に、成形性や強度向上のために、Mg含有量を比較的多めにする。Mg含有量が2.5質量%未満では強度が不足し、加工硬化特性が低下する。但し、4.5質量%を超えると、板の圧延性が低下し、SCC感受性も強くなる。従って、Mg含有量は2.5~4.5%の各範囲とする。 Mg: 2.5-4.5%
Mg, which is an essential alloy element, together with Zn, forms clusters during room temperature aging of the prepared tempered plate to improve work hardening characteristics and improve formability. In addition, an aging precipitate is formed during the artificial aging treatment after the forming process to the structural material, thereby improving the strength. In the present invention, in order to suppress the Zn content relatively low, conversely, the Mg content is made relatively large in order to improve moldability and strength. If the Mg content is less than 2.5% by mass, the strength is insufficient and the work hardening characteristics are deteriorated. However, if it exceeds 4.5 mass%, the rollability of the plate is lowered, and the SCC sensitivity is enhanced. Therefore, the Mg content is in the range of 2.5 to 4.5%.
必須の合金元素であるMgは、Znとともに、製造された調質後の板の室温時効時にクラスタを形成して加工硬化特性を向上させ、成形性を向上させる。また、構造材への成形加工後の人工時効処理時に時効析出物を形成して強度を向上させる。本発明では、Zn含有量を比較的低めに抑制するため、逆に、成形性や強度向上のために、Mg含有量を比較的多めにする。Mg含有量が2.5質量%未満では強度が不足し、加工硬化特性が低下する。但し、4.5質量%を超えると、板の圧延性が低下し、SCC感受性も強くなる。従って、Mg含有量は2.5~4.5%の各範囲とする。 Mg: 2.5-4.5%
Mg, which is an essential alloy element, together with Zn, forms clusters during room temperature aging of the prepared tempered plate to improve work hardening characteristics and improve formability. In addition, an aging precipitate is formed during the artificial aging treatment after the forming process to the structural material, thereby improving the strength. In the present invention, in order to suppress the Zn content relatively low, conversely, the Mg content is made relatively large in order to improve moldability and strength. If the Mg content is less than 2.5% by mass, the strength is insufficient and the work hardening characteristics are deteriorated. However, if it exceeds 4.5 mass%, the rollability of the plate is lowered, and the SCC sensitivity is enhanced. Therefore, the Mg content is in the range of 2.5 to 4.5%.
ZnとMgとのバランス式
本発明では、成形性と高強度化、そして耐食性を確保するために、前記した通り、Zn含有量を比較的低めに抑制するとともに、Mg含有量を比較的多めにする。このために、Znの含有量[Zn](質量%)と、Mgの含有量[Mg] (質量%)とが、[Zn]≧-0.3[Mg]+4.5のバランス式、好ましくは[Zn]≧-0.5[Mg]+5.75のバランス式を満たすようにする。 In the present invention, in order to secure moldability, high strength, and corrosion resistance, as described above, the Zn content is suppressed to be relatively low, and the Mg content is relatively increased. To do. For this reason, the Zn content [Zn] (mass%) and the Mg content [Mg] (mass%) are preferably balanced expressions of [Zn] ≧ −0.3 [Mg] +4.5, preferably Satisfies the balance equation of [Zn] ≧ −0.5 [Mg] +5.75.
本発明では、成形性と高強度化、そして耐食性を確保するために、前記した通り、Zn含有量を比較的低めに抑制するとともに、Mg含有量を比較的多めにする。このために、Znの含有量[Zn](質量%)と、Mgの含有量[Mg] (質量%)とが、[Zn]≧-0.3[Mg]+4.5のバランス式、好ましくは[Zn]≧-0.5[Mg]+5.75のバランス式を満たすようにする。 In the present invention, in order to secure moldability, high strength, and corrosion resistance, as described above, the Zn content is suppressed to be relatively low, and the Mg content is relatively increased. To do. For this reason, the Zn content [Zn] (mass%) and the Mg content [Mg] (mass%) are preferably balanced expressions of [Zn] ≧ −0.3 [Mg] +4.5, preferably Satisfies the balance equation of [Zn] ≧ −0.5 [Mg] +5.75.
この[Zn]≧-0.3[Mg]+4.5を満足することによって、後述する好ましい製造方法との組み合わせで、人工時効処理後の構造材の0.2%耐力を380MPa以上とすることが可能となる。また、 好ましくは、[Zn]≧-0.5[Mg]+5.75を満足することによって、後述する好ましい製造方法との組み合わせで、人工時効処理後の構造材の0.2%耐力を400MPa以上とすることが可能となる。
By satisfying this [Zn] ≧ −0.3 [Mg] +4.5, the 0.2% proof stress of the structural material after artificial aging treatment is set to 380 MPa or more in combination with a preferable manufacturing method described later. Is possible. Further, preferably, by satisfying [Zn] ≧ −0.5 [Mg] +5.75, the 0.2% proof stress of the structural material after artificial aging treatment is 400 MPa in combination with a preferable manufacturing method described later. This is possible.
ZnとMgの各含有量が、[Zn]<-0.3[Mg]+4.5では、Zn含有量を比較的低めに抑制した場合には、ZnとMgの各含有量が規定範囲内であっても、あるいは後述する好ましい製造方法によっても、人工時効処理後の構造材の0.2%耐力を350MPa以上とできなくなる可能性がある。また、Znの含有量とMgの含有量とが[Zn]<0.5[Mg]+5.75では、同様に人工時効処理後の構造材の0.2%耐力を400MPa以上とできなくなる可能性がある。
When the contents of Zn and Mg are [Zn] <− 0.3 [Mg] +4.5, the contents of Zn and Mg are within the specified range when the Zn content is suppressed relatively low. Even in this case, or by a preferable manufacturing method to be described later, there is a possibility that the 0.2% proof stress of the structural material after the artificial aging treatment cannot be 350 MPa or more. Further, when the Zn content and the Mg content are [Zn] <0.5 [Mg] +5.75, the 0.2% proof stress of the structural material after the artificial aging treatment cannot be set to 400 MPa or more. There is sex.
Cu:0.05~0.5%
Cuは、Al-Zn-Mg系合金のSCC感受性を抑え、耐SCC性を向上させる作用がある。また、一般耐食性も向上させる。Cu含有量が0.05%未満では、耐SCC性や一般耐食性の向上効果が小さい。一方、Cu含有量が0.5%を超えると、圧延性及び溶接性などの諸特性を却って低下させる。従って、Cu含有量の下限は0.05%、好ましくは0.10%である。また、上限は0.5%、好ましくは0.4%である。 Cu: 0.05 to 0.5%
Cu has the effect of suppressing the SCC sensitivity of the Al—Zn—Mg alloy and improving the SCC resistance. It also improves general corrosion resistance. When the Cu content is less than 0.05%, the effect of improving SCC resistance and general corrosion resistance is small. On the other hand, if the Cu content exceeds 0.5%, various properties such as rollability and weldability are reduced. Therefore, the lower limit of the Cu content is 0.05%, preferably 0.10%. Further, the upper limit is 0.5%, preferably 0.4%.
Cuは、Al-Zn-Mg系合金のSCC感受性を抑え、耐SCC性を向上させる作用がある。また、一般耐食性も向上させる。Cu含有量が0.05%未満では、耐SCC性や一般耐食性の向上効果が小さい。一方、Cu含有量が0.5%を超えると、圧延性及び溶接性などの諸特性を却って低下させる。従って、Cu含有量の下限は0.05%、好ましくは0.10%である。また、上限は0.5%、好ましくは0.4%である。 Cu: 0.05 to 0.5%
Cu has the effect of suppressing the SCC sensitivity of the Al—Zn—Mg alloy and improving the SCC resistance. It also improves general corrosion resistance. When the Cu content is less than 0.05%, the effect of improving SCC resistance and general corrosion resistance is small. On the other hand, if the Cu content exceeds 0.5%, various properties such as rollability and weldability are reduced. Therefore, the lower limit of the Cu content is 0.05%, preferably 0.10%. Further, the upper limit is 0.5%, preferably 0.4%.
Zr:0.05~0.3%、Mn:0.1~1.5%、Cr:0.05~0.3%、Sc:0.05~0.3%の1種又は2種以上
Zr、Mn、Cr、Scの遷移元素は、鋳塊及び最終製品の結晶粒を微細化して強度向上に寄与するので、必要な場合には選択的に含有させる。これらをいずれか一種、或いは二種以上を含有する場合、Zr、Mn、Cr、Scの含有量がいずれも下限未満では、含有量が不足して、強度が低下する。一方、Zr、Mn、Cr、Scの含有量がそれぞれの上限を超えた場合には、粗大晶出物を形成するため伸びが低下する。従って、これらを含有させる場合の含有量は、Zrの下限は0.05%、好ましくは0.08%であり、上限は0.3%、好ましくは0.2%である。Mnの下限は0.1%、好ましくは0.2%であり、上限は1.5%、好ましくは1.0%である。Crの下限は0.05%、好ましくは0.1%であり、上限は0.3%、好ましくは0.2%である。Scの下限は0.05%、好ましくは0.1%であり、上限は0.3%、好ましくは0.2%である。 One or more of Zr: 0.05 to 0.3%, Mn: 0.1 to 1.5%, Cr: 0.05 to 0.3%, Sc: 0.05 to 0.3% Since the transition elements of Zr, Mn, Cr, and Sc contribute to improvement in strength by refining the crystal grains of the ingot and the final product, they are selectively contained when necessary. When any one or two or more of these are contained, if the content of Zr, Mn, Cr, or Sc is less than the lower limit, the content is insufficient and the strength is lowered. On the other hand, when the contents of Zr, Mn, Cr, and Sc exceed the respective upper limits, the elongation decreases because coarse crystals are formed. Therefore, the content in the case of containing these is 0.05%, preferably 0.08% for the lower limit of Zr, and 0.3%, preferably 0.2% for the upper limit. The lower limit of Mn is 0.1%, preferably 0.2%, and the upper limit is 1.5%, preferably 1.0%. The lower limit of Cr is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%. The lower limit of Sc is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%.
Zr、Mn、Cr、Scの遷移元素は、鋳塊及び最終製品の結晶粒を微細化して強度向上に寄与するので、必要な場合には選択的に含有させる。これらをいずれか一種、或いは二種以上を含有する場合、Zr、Mn、Cr、Scの含有量がいずれも下限未満では、含有量が不足して、強度が低下する。一方、Zr、Mn、Cr、Scの含有量がそれぞれの上限を超えた場合には、粗大晶出物を形成するため伸びが低下する。従って、これらを含有させる場合の含有量は、Zrの下限は0.05%、好ましくは0.08%であり、上限は0.3%、好ましくは0.2%である。Mnの下限は0.1%、好ましくは0.2%であり、上限は1.5%、好ましくは1.0%である。Crの下限は0.05%、好ましくは0.1%であり、上限は0.3%、好ましくは0.2%である。Scの下限は0.05%、好ましくは0.1%であり、上限は0.3%、好ましくは0.2%である。 One or more of Zr: 0.05 to 0.3%, Mn: 0.1 to 1.5%, Cr: 0.05 to 0.3%, Sc: 0.05 to 0.3% Since the transition elements of Zr, Mn, Cr, and Sc contribute to improvement in strength by refining the crystal grains of the ingot and the final product, they are selectively contained when necessary. When any one or two or more of these are contained, if the content of Zr, Mn, Cr, or Sc is less than the lower limit, the content is insufficient and the strength is lowered. On the other hand, when the contents of Zr, Mn, Cr, and Sc exceed the respective upper limits, the elongation decreases because coarse crystals are formed. Therefore, the content in the case of containing these is 0.05%, preferably 0.08% for the lower limit of Zr, and 0.3%, preferably 0.2% for the upper limit. The lower limit of Mn is 0.1%, preferably 0.2%, and the upper limit is 1.5%, preferably 1.0%. The lower limit of Cr is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%. The lower limit of Sc is 0.05%, preferably 0.1%, and the upper limit is 0.3%, preferably 0.2%.
Ag:0.01~0.2%、Sn:0.001~0.1%の1種又は2種
Ag及びSnは、構造材への成形加工後の人工時効処理によって強度向上に寄与する時効析出物を微細に析出させ、高強度化を促進する効果があるので、必要に応じて選択的に含有させる。これらをいずれか一方又は両方含有する場合、Sn含有量が0.001%未満、Ag含有量が0.01%未満では、強度向上効果が小さい。一方、SnやAg含有量が多すぎると、圧延性及び溶接性などの諸特性を却って低下させる。また、強度向上効果も飽和し、Agに関しては高価となるだけである。従って、Ag:0.01~0.2%、Sn:0.001~0.1%の範囲とする。 One or two of Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1%
Ag and Sn have the effect of finely precipitating aging precipitates that contribute to strength improvement by artificial aging treatment after forming into a structural material and promoting high strength. Let When one or both of these are contained, if the Sn content is less than 0.001% and the Ag content is less than 0.01%, the strength improvement effect is small. On the other hand, when there is too much Sn and Ag content, various characteristics, such as rolling property and weldability, will be reduced. In addition, the strength improvement effect is saturated, and Ag is only expensive. Therefore, Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1% are set.
Ag及びSnは、構造材への成形加工後の人工時効処理によって強度向上に寄与する時効析出物を微細に析出させ、高強度化を促進する効果があるので、必要に応じて選択的に含有させる。これらをいずれか一方又は両方含有する場合、Sn含有量が0.001%未満、Ag含有量が0.01%未満では、強度向上効果が小さい。一方、SnやAg含有量が多すぎると、圧延性及び溶接性などの諸特性を却って低下させる。また、強度向上効果も飽和し、Agに関しては高価となるだけである。従って、Ag:0.01~0.2%、Sn:0.001~0.1%の範囲とする。 One or two of Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1%
Ag and Sn have the effect of finely precipitating aging precipitates that contribute to strength improvement by artificial aging treatment after forming into a structural material and promoting high strength. Let When one or both of these are contained, if the Sn content is less than 0.001% and the Ag content is less than 0.01%, the strength improvement effect is small. On the other hand, when there is too much Sn and Ag content, various characteristics, such as rolling property and weldability, will be reduced. In addition, the strength improvement effect is saturated, and Ag is only expensive. Therefore, Ag: 0.01 to 0.2% and Sn: 0.001 to 0.1% are set.
その他の元素
これら以外のその他の元素は基本的に不可避的不純物である。溶解原料として、純アルミニウム地金以外に、アルミニウム合金スクラップの使用による、これら不純物元素の混入なども想定(許容)して、7000系合金のJIS規格で規定する範囲での各々の含有を許容する。例えば、Ti、Bは、圧延板としては不純物であるが、鋳塊の結晶粒を微細化する効果もあるので、Tiの上限は0.2%、好ましくは0.1%、Bの上限は0.05%、好ましくは0.03%とする。Fe、Siは、Fe:0.5%以下、Si:0.5%以下であれば、本発明に係るアルミニウム合金圧延板の特性に影響せず、含有が許容される。 Other elements Other elements other than these are basically inevitable impurities. As a melting raw material, in addition to pure aluminum ingots, the inclusion of these impurity elements due to the use of aluminum alloy scrap is assumed (allowed), and each content within the range specified by the JIS standard of 7000 series alloys is allowed. . For example, Ti and B are impurities as a rolled plate, but also have the effect of refining the crystal grains of the ingot, so the upper limit of Ti is 0.2%, preferably 0.1%, and the upper limit of B is 0.05%, preferably 0.03%. Fe and Si are allowed to be contained without affecting the characteristics of the aluminum alloy rolled sheet according to the present invention as long as Fe: 0.5% or less and Si: 0.5% or less.
これら以外のその他の元素は基本的に不可避的不純物である。溶解原料として、純アルミニウム地金以外に、アルミニウム合金スクラップの使用による、これら不純物元素の混入なども想定(許容)して、7000系合金のJIS規格で規定する範囲での各々の含有を許容する。例えば、Ti、Bは、圧延板としては不純物であるが、鋳塊の結晶粒を微細化する効果もあるので、Tiの上限は0.2%、好ましくは0.1%、Bの上限は0.05%、好ましくは0.03%とする。Fe、Siは、Fe:0.5%以下、Si:0.5%以下であれば、本発明に係るアルミニウム合金圧延板の特性に影響せず、含有が許容される。 Other elements Other elements other than these are basically inevitable impurities. As a melting raw material, in addition to pure aluminum ingots, the inclusion of these impurity elements due to the use of aluminum alloy scrap is assumed (allowed), and each content within the range specified by the JIS standard of 7000 series alloys is allowed. . For example, Ti and B are impurities as a rolled plate, but also have the effect of refining the crystal grains of the ingot, so the upper limit of Ti is 0.2%, preferably 0.1%, and the upper limit of B is 0.05%, preferably 0.03%. Fe and Si are allowed to be contained without affecting the characteristics of the aluminum alloy rolled sheet according to the present invention as long as Fe: 0.5% or less and Si: 0.5% or less.
(組織)
以上の合金組成を前提として、本発明の7000系アルミニウム合金板組織を、製造された調質後、2週間以上室温時効させた後の冷延板にて規定する。このため、この冷延板を溶体化および焼入れ処理後に、2週間以上室温時効させた(調質T4の)組織とした上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒界析出物(室温時効析出物)のZnとMgとの平均組成比(Zn/Mg)を規定する。また、同時に、前記溶体化および焼入れ処理後に2週間以上室温時効させた板を、更に
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
のいずれか一方を行った上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)を規定する。 (Organization)
Based on the above alloy composition, the 7000 series aluminum alloy sheet structure of the present invention is defined by a cold-rolled sheet after tempering and aging at room temperature for 2 weeks or more. For this reason, after this cold-rolled sheet is made into a structure (tempered T4) aged at room temperature for 2 weeks or more after solution treatment and quenching treatment, this structure is observed with a transmission electron microscope of 60000 times. The average composition ratio (Zn / Mg) of Zn and Mg of the grain boundary precipitate (room temperature aging precipitate) is defined. At the same time, a plate which has been aged at room temperature for 2 weeks or more after the solution treatment and quenching treatment is further subjected to (I) a heat treatment temperature of the second stage for 2 hours or more in the range of the first stage heat treatment temperature of 70 to 100 ° C. Two-stage artificial aging treatment for 5 hours or more in the range of 100-170 ° C,
Or
(II) One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C. is performed, and this structure is observed with a transmission electron microscope of 60000 times. The average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is defined.
以上の合金組成を前提として、本発明の7000系アルミニウム合金板組織を、製造された調質後、2週間以上室温時効させた後の冷延板にて規定する。このため、この冷延板を溶体化および焼入れ処理後に、2週間以上室温時効させた(調質T4の)組織とした上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒界析出物(室温時効析出物)のZnとMgとの平均組成比(Zn/Mg)を規定する。また、同時に、前記溶体化および焼入れ処理後に2週間以上室温時効させた板を、更に
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
のいずれか一方を行った上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)を規定する。 (Organization)
Based on the above alloy composition, the 7000 series aluminum alloy sheet structure of the present invention is defined by a cold-rolled sheet after tempering and aging at room temperature for 2 weeks or more. For this reason, after this cold-rolled sheet is made into a structure (tempered T4) aged at room temperature for 2 weeks or more after solution treatment and quenching treatment, this structure is observed with a transmission electron microscope of 60000 times. The average composition ratio (Zn / Mg) of Zn and Mg of the grain boundary precipitate (room temperature aging precipitate) is defined. At the same time, a plate which has been aged at room temperature for 2 weeks or more after the solution treatment and quenching treatment is further subjected to (I) a heat treatment temperature of the second stage for 2 hours or more in the range of the first stage heat treatment temperature of 70 to 100 ° C. Two-stage artificial aging treatment for 5 hours or more in the range of 100-170 ° C,
Or
(II) One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C. is performed, and this structure is observed with a transmission electron microscope of 60000 times. The average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is defined.
粒界析出物の組成
本発明では、前記調質T4の板の組織の、60000倍の透過型電子顕微鏡にて観察される粒界析出物(室温時効析出物)のZnとMgとの平均組成比(Zn/Mg)を0.5~3.0の範囲とする。 Composition of grain boundary precipitates In the present invention, the average composition of Zn and Mg of grain boundary precipitates (room temperature aging precipitates) observed with a transmission electron microscope of 60000 times the texture of the tempered T4 plate The ratio (Zn / Mg) is in the range of 0.5 to 3.0.
本発明では、前記調質T4の板の組織の、60000倍の透過型電子顕微鏡にて観察される粒界析出物(室温時効析出物)のZnとMgとの平均組成比(Zn/Mg)を0.5~3.0の範囲とする。 Composition of grain boundary precipitates In the present invention, the average composition of Zn and Mg of grain boundary precipitates (room temperature aging precipitates) observed with a transmission electron microscope of 60000 times the texture of the tempered T4 plate The ratio (Zn / Mg) is in the range of 0.5 to 3.0.
室温時効析出物としての粒界析出物のZnとMgとの平均組成比(Zn/Mg)を、この数値範囲とすることによって、粒界析出物(室温時効析出物)中のZn含有量(Zn組成比)を減らす一方で、相対的にMgを増やすことができる。これによって、合金組成のZn含有量を下げても、この粒界析出物として(無駄に)消費されるZn量を低下させ、マトリックス中のZn固溶量を増やし、確保することができる。これによって、その後の人工時効処理時の時効析出物の形成に必要なZn量を最大化させられ、強度と成形性のバランスやBH性を最大化できる。
By setting the average composition ratio (Zn / Mg) of Zn and Mg of the grain boundary precipitate as the room temperature aging precipitate within this numerical range, the Zn content in the grain boundary precipitate (room temperature aging precipitate) ( While reducing the Zn composition ratio), it is possible to relatively increase Mg. As a result, even if the Zn content of the alloy composition is lowered, the amount of Zn consumed (unnecessarily) as this grain boundary precipitate can be reduced, and the amount of Zn solid solution in the matrix can be increased and secured. As a result, the amount of Zn required for the formation of aging precipitates during the subsequent artificial aging treatment can be maximized, and the balance between strength and formability and BH properties can be maximized.
本発明では、このように室温時効により生成する粒界析出物組成を規定するため、TEMによる組織の測定を、溶体化焼入れ処理などの調質処理直後の、室温時効していない板の状態ではなく、目安として、2週間以上室温時効(室温放置)した後の板であって、構造材への成形加工前および人工時効処理前の板に対して行う。調質処理後2週間以上室温時効(室温放置)した後の板であれば、その後の時間経過による室温時効によっても、粒界析出物の組成比の経時変化は無視できるほど小さい。
In the present invention, in order to define the composition of the grain boundary precipitates generated by room temperature aging in this way, the structure of the structure by TEM is measured immediately after the tempering treatment such as solution hardening treatment in the state of the plate not aging at room temperature Roughly, as a guide, it is a plate after aging (room temperature standing) for 2 weeks or more, which is performed on the plate before forming the structure material and before the artificial aging treatment. In the case of a plate after aging (room temperature standing) for 2 weeks or more after the tempering treatment, the change with time in the composition ratio of the grain boundary precipitates is negligibly small even by the subsequent room temperature aging.
粒界析出物のZnとMgとの平均組成比(Zn/Mg)が上限値3.0を超えて、前記規定範囲を高めに外れると、従来技術におけるZn量が多い粒界析出物(室温時効析出物)組成と大差なくなる。このため、合金組成としてのZn含有量を下げた場合には、粒界析出物中のZn含有量(Zn組成比)が多いので、この粒界析出物に無駄に消費されるZn量が増して、マトリックス中のZn固溶量が減りすぎ、必要固溶量を確保できなくなる。この結果、その後の人工時効処理時の時効析出物の形成に必要なZn量が減り、強度と成形性のバランスが低下する。
When the average composition ratio (Zn / Mg) of Zn and Mg in the grain boundary precipitate exceeds the upper limit of 3.0 and deviates from the above specified range, the grain boundary precipitate having a large amount of Zn in the prior art (room temperature) Aging precipitate) No significant difference from the composition. For this reason, when the Zn content as the alloy composition is lowered, the Zn content (Zn composition ratio) in the grain boundary precipitates is large, so that the amount of Zn consumed in the grain boundary precipitates is increased. As a result, the amount of Zn solid solution in the matrix decreases too much, and the required amount of solid solution cannot be ensured. As a result, the amount of Zn required for the formation of aging precipitates during the subsequent artificial aging treatment is reduced, and the balance between strength and formability is lowered.
一方、粒界析出物のZnとMgとの平均組成比(Zn/Mg)が下限値0.5未満で、前記規定範囲を低めに外れると、板の組成としてのZn含有量自体が不足していることを意味し、BH性が低下して、7000系アルミニウム合金とする意味自体が失われる。
On the other hand, if the average composition ratio (Zn / Mg) between Zn and Mg in the grain boundary precipitates is less than the lower limit of 0.5 and falls outside the specified range, the Zn content itself as the composition of the plate is insufficient. This means that the BH property is lowered and the meaning of making a 7000 series aluminum alloy is lost.
粒内析出物の組成
本発明では、前記粒界析出物と同時に、製造された調質後の冷延板のBH性を保証するために、前記調質後2週間以上室温時効後の板に、特定条件の人工時効処理を施した後の組織として、人工時効析出物の組成を規定する。このため、前記調質T4の板を、
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
のいずれか一方を行った上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒内析出物(人工時効析出物)のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であるものとする。 Composition of intragranular precipitate In the present invention, in order to guarantee the BH property of the manufactured cold-rolled sheet simultaneously with the grain boundary precipitate, it is applied to the plate after aging for 2 weeks or more at room temperature. The composition of the artificial aging precipitate is defined as the structure after the artificial aging treatment under specific conditions. For this reason, the plate of the tempered T4 is
(I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more.
Or
(II) One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C. is performed, and this structure is observed with a transmission electron microscope of 60000 times. It is assumed that the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate (artificial aging precipitate) is in the range of 1.5 to 3.5.
本発明では、前記粒界析出物と同時に、製造された調質後の冷延板のBH性を保証するために、前記調質後2週間以上室温時効後の板に、特定条件の人工時効処理を施した後の組織として、人工時効析出物の組成を規定する。このため、前記調質T4の板を、
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
のいずれか一方を行った上で、この組織の、60000倍の透過型電子顕微鏡にて観察される粒内析出物(人工時効析出物)のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であるものとする。 Composition of intragranular precipitate In the present invention, in order to guarantee the BH property of the manufactured cold-rolled sheet simultaneously with the grain boundary precipitate, it is applied to the plate after aging for 2 weeks or more at room temperature. The composition of the artificial aging precipitate is defined as the structure after the artificial aging treatment under specific conditions. For this reason, the plate of the tempered T4 is
(I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more.
Or
(II) One-step artificial aging treatment for 12 to 36 hours at a heat treatment temperature range of 100 to 150 ° C. is performed, and this structure is observed with a transmission electron microscope of 60000 times. It is assumed that the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate (artificial aging precipitate) is in the range of 1.5 to 3.5.
人工時効析出物としての粒内析出物のZnとMgとの平均組成比(Zn/Mg)をこの数値範囲とすることによって、人工時効析出物としての粒内析出物中のZn含有量を減らすことができる。これによって、合金組成としてのZn含有量を下げても、粒内析出物中のZn含有量(Zn組成比)を減らすことができ、人工時効析出物(量)の形成に必要なZn量が少なくて済む。この結果、より少ないZn含有量の合金組成でも、人工時効処理時の、強化に寄与する時効析出物の析出量を最大化させられ、強度と成形性のバランスやBH性を最大化できる。
By setting the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate as the artificial aging precipitate within this numerical range, the Zn content in the intragranular precipitate as the artificial aging precipitate is reduced. be able to. As a result, even if the Zn content as the alloy composition is lowered, the Zn content (Zn composition ratio) in the intragranular precipitate can be reduced, and the amount of Zn necessary for the formation of the artificial aging precipitate (amount) can be reduced. Less is enough. As a result, even with an alloy composition having a smaller Zn content, the amount of aging precipitates contributing to strengthening during the artificial aging treatment can be maximized, and the balance between strength and formability and BH properties can be maximized.
この粒内析出物は、板製造後(調質後の)の時間経過による室温時効によって、組成比の経時変化が大きくなるので、前記粒内析出物のZnとMgとの平均組成比(Zn/Mg)の測定は、再現性の点で、前記粒界析出物を測定したのと同じ板(調質処理後に室温時効させた板)を前記特定条件の人工時効硬化処理をした板を対象として行う。なお、この人工時効処理条件によっても、当然ながら、粒内析出物の数密度やZnとMgとの平均組成比(Zn/Mg)は多少影響を受けるので、測定の再現性の点で、本発明では、ワンポイントである30℃/分の昇温速度で90℃まで加熱して3時間保持後、更に30℃/分の昇温速度で140℃まで加熱して8時間保持する2段階での人工時効硬化処理条件を採用することが好ましい。
This intragranular precipitate has an increased composition ratio over time due to room temperature aging after the production of the plate (after tempering), so the average composition ratio (Zn) of Zn and Mg in the intragranular precipitate / Mg) for reproducibility, the same plate (the plate aged at room temperature after the tempering treatment) from which the grain boundary precipitates were measured was subjected to the artificial age hardening treatment under the specific conditions. Do as. Note that the number density of the intragranular precipitates and the average composition ratio of Zn and Mg (Zn / Mg) are naturally affected by this artificial aging treatment condition. Heating up to 90 ° C at a heating rate of 30 ° C / min, which is one point, holding for 3 hours, then heating up to 140 ° C at a heating rate of 30 ° C / min and holding for 8 hours It is preferable to employ age hardening treatment conditions.
これに対して、前記粒内析出物のZnとMgとの平均組成比が上限値3.5を超えて、前記規定範囲を高めに外れると、従来技術における、Znが多い粒内析出物の組成と大差なくなる。このため、合金組成としてのZn含有量を下げた場合には、粒内析出物中のZn含有量(Zn組成比)が多いので、人工時効処理時の時効析出物(量)の形成に必要なZn量が多くなり、粒内析出物形成にZnがより多く消費される。このため、より少ないZn含有量の合金組成では、人工時効処理時の、強化に寄与する時効析出物の析出量が低下して、強度と成形性のバランスやBH性が低くなる。
On the other hand, when the average composition ratio of Zn and Mg in the intragranular precipitate exceeds the upper limit value 3.5 and deviates from the specified range, the intragranular precipitate in the prior art has a high Zn content. There is no great difference from the composition. For this reason, when the Zn content as the alloy composition is lowered, the content of Zn in the intragranular precipitate (Zn composition ratio) is large, so it is necessary to form an aging precipitate (amount) during artificial aging treatment. As a result, the amount of Zn increases, and more Zn is consumed to form intragranular precipitates. For this reason, with an alloy composition having a smaller Zn content, the amount of aging precipitates contributing to strengthening during the artificial aging treatment is reduced, and the balance between strength and formability and BH properties are lowered.
一方、粒内析出物のZnとMgとの平均組成比(Zn/Mg)が下限値1.5未満で、前記規定範囲を低めに外れると、板の組成としてのZn含有量自体が不足していることを意味し、人工時効析出物である粒内析出物が減少し、BH性が低下して、7000系アルミニウム合金とする意味自体が失われる。
On the other hand, if the average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is less than the lower limit of 1.5 and deviates from the specified range, the Zn content itself as the composition of the plate is insufficient. This means that the intragranular precipitates, which are artificial aging precipitates, are reduced, the BH property is lowered, and the meaning itself of making a 7000 series aluminum alloy is lost.
以上の粒界および粒内の析出物の規定によって、Zn含有量を抑えた7000系アルミニウム合金板であっても、強度と延性(成形性)のバランスを向上させることができ、常法によって製造される圧延板として、380MPa以上、好ましくは400MPa以上の0.2%耐力(BH性)と、プレス成形加工性とを兼備し、耐SCC性などの耐食性にも優れた構造用7000系アルミニウム合金板を提供できる。
Even with a 7000 series aluminum alloy plate with a reduced Zn content, the balance between strength and ductility (formability) can be improved by the above grain boundary and grain precipitates. As a rolled sheet, a structural 7000 series aluminum alloy having both 0.2% proof stress (BH property) of 380 MPa or more, preferably 400 MPa or more, and press forming workability, and excellent corrosion resistance such as SCC resistance. Can provide a board.
粒界析出物と粒内析出物の組成の測定
本発明において、60000倍のTEM(透過型電子顕微鏡)にて観察される粒界析出物とは、結晶の粒界上に、点々と並んで観察される不定形の析出物で、前記TEMにて観察可能で、TEM-EDXで、そのZnとMgとの平均組成比が定量分析可能な、個々の円相当径が10~200nm程度の大きさの析出物である。ちなみに、その円相当径とは、不定形である化合物と同じ面積を有する円の直径であり、化合物の大きさを正確に、かつ再現性良く測定あるいは規定する方法として、従来から汎用されている。 Measurement of Composition of Grain Boundary Precipitates and Intragranular Precipitates In the present invention, the grain boundary precipitates observed with a 60000 times TEM (transmission electron microscope) are lined up on the crystal grain boundaries. Observed amorphous precipitates, which can be observed with the TEM, and with TEM-EDX, the average composition ratio of Zn and Mg can be quantitatively analyzed. The equivalent circle diameter is as large as about 10 to 200 nm. This is a precipitate. Incidentally, the equivalent circle diameter is the diameter of a circle having the same area as an indeterminate compound, and has been widely used as a method for measuring or defining the size of a compound accurately and reproducibly. .
本発明において、60000倍のTEM(透過型電子顕微鏡)にて観察される粒界析出物とは、結晶の粒界上に、点々と並んで観察される不定形の析出物で、前記TEMにて観察可能で、TEM-EDXで、そのZnとMgとの平均組成比が定量分析可能な、個々の円相当径が10~200nm程度の大きさの析出物である。ちなみに、その円相当径とは、不定形である化合物と同じ面積を有する円の直径であり、化合物の大きさを正確に、かつ再現性良く測定あるいは規定する方法として、従来から汎用されている。 Measurement of Composition of Grain Boundary Precipitates and Intragranular Precipitates In the present invention, the grain boundary precipitates observed with a 60000 times TEM (transmission electron microscope) are lined up on the crystal grain boundaries. Observed amorphous precipitates, which can be observed with the TEM, and with TEM-EDX, the average composition ratio of Zn and Mg can be quantitatively analyzed. The equivalent circle diameter is as large as about 10 to 200 nm. This is a precipitate. Incidentally, the equivalent circle diameter is the diameter of a circle having the same area as an indeterminate compound, and has been widely used as a method for measuring or defining the size of a compound accurately and reproducibly. .
また、60000倍のTEMにて観察される粒内析出物とは、結晶の粒内に点在する不定形の析出物で、前記TEMにて観察可能で、TEM-EDXで、そのZnとMgとの平均組成比が定量分析可能な、個々の円相当径が1~50nm程度の大きさの析出物である。
Further, the intragranular precipitates observed with a 60000-fold TEM are indeterminate precipitates scattered in the crystal grains, which can be observed with the TEM, and with TEM-EDX, the Zn and Mg The equivalent circle diameter is a precipitate having a size of about 1 to 50 nm that can be quantitatively analyzed.
なお、円相当径が前記した大きさを超えるような粗大な粒界あるいは粒内析出物は、板の基本的な機械的特性や品質を著しく阻害する。このため、通常の板の製法や品質管理では、極力、このように粗大な析出物を存在させないように製造しており、TEMによる測定範囲として意味が無いので、測定対象から外す。また、円相当径が前記した大きさ未満の粒界あるいは粒内析出物は、TEMの検出限界になるとともに、微小すぎてEDXでのZnとMgとの組成比の分析の誤差となりやすいので、測定対象から外す。
It should be noted that coarse grain boundaries or intragranular precipitates whose equivalent circle diameter exceeds the above-described size significantly impairs the basic mechanical properties and quality of the plate. For this reason, in the manufacturing method and quality control of a normal board, it manufactures so that such a coarse precipitate may not exist as much as possible, and since it is meaningless as a measurement range by TEM, it excludes from a measuring object. In addition, grain boundaries or intragranular precipitates having an equivalent circle diameter less than the above-mentioned size become the detection limit of TEM, and are too small and easily cause errors in the analysis of the composition ratio of Zn and Mg in EDX. Remove from measurement.
ここで、TEM-EDXとは、本発明で用いるTEMに通常付属しているX線分光装置であり、エネルギー分散型X線分光法(Energy Dispersive X-ray Spectroscopy)による分析装置として周知で、通常EDXと称される。このX線分光装置は、TEMによって観察される化合物(析出物)の組成などの同定や定量分析に汎用される。本発明でも、このX線分光装置を用いて、前記TEMにより観察される粒界と粒内の各析出物のZnとMgとの平均組成比を算出する。
Here, TEM-EDX is an X-ray spectrometer that is normally attached to the TEM used in the present invention, and is well known as an analyzer using energy dispersive X-ray spectroscopy (Energy Dispersive X-ray Spectroscopy). It is called EDX. This X-ray spectrometer is widely used for identification and quantitative analysis of the composition of a compound (precipitate) observed by TEM. Also in the present invention, this X-ray spectrometer is used to calculate the average composition ratio of Zn and Mg of the grain boundaries observed by the TEM and the respective precipitates in the grains.
また、規定する粒界と粒内の各析出物のZnとMgとの平均組成比とは、測定対象なる供試板の表面から板厚方向1/4部の任意の点、10箇所について行い(試料を10個採取し)、これらの測定結果を平均化して算出するという意味である。より具体的には、供試板の板厚方向の直角断面につき、表面から板厚方向1/4部の任意の点を通り、板表面に平行な面について、60000倍のTEM(透過型電子顕微鏡)を用いて測定する。試料は、上記部位から10個サンプリングした板断面試料表面を機械研磨して、板表面から約0.25mmを機械研磨により削り落とし、更に、バフ研磨を行なって表面を調整した試料を用意する。次に、反射電子像を利用し、自動解析装置により、視野内の測定対象となる前記粒界と粒内の各析出物を特定した上で、これら析出物のZnとMgとの平均組成比を測定して、その平均値を算出する。測定部位は試料研磨表面、1試料あたりの測定領域は240μm×180μmとする。
Moreover, the average composition ratio of Zn and Mg of the grain boundaries to be defined and the precipitates in the grains is determined at arbitrary points and 10 points in the 1/4 thickness direction from the surface of the test plate to be measured. This means that 10 samples are collected and the measurement results are averaged. More specifically, with respect to a cross section perpendicular to the plate thickness direction of the test plate, a TEM (transmission electron) of 60000 times the plane parallel to the plate surface passing through an arbitrary point from the surface to ¼ part in the plate thickness direction. Measure using a microscope. A sample is prepared by mechanically polishing a plate cross-section sample surface sampled 10 pieces from the above-mentioned site, cutting off about 0.25 mm from the plate surface by mechanical polishing, and further performing buffing to adjust the surface. Next, using the backscattered electron image, the grain boundary to be measured in the visual field and each precipitate in the grain are specified by an automatic analyzer, and the average composition ratio of Zn and Mg in these precipitates Is measured and the average value is calculated. The measurement site is the sample polishing surface, and the measurement area per sample is 240 μm × 180 μm.
(製造方法)
本発明における7000系アルミニウム合金板の製造方法について、以下に具体的に説明する。 (Production method)
The method for producing a 7000 series aluminum alloy plate in the present invention will be specifically described below.
本発明における7000系アルミニウム合金板の製造方法について、以下に具体的に説明する。 (Production method)
The method for producing a 7000 series aluminum alloy plate in the present invention will be specifically described below.
本発明では、7000系アルミニウム合金板の通常の製造工程による製造方法で製造可能である。即ち、鋳造(DC鋳造法や連続鋳造法)、均質化熱処理、熱間圧延の通常の各製造工程を経て製造され、板厚が1.5~5.0mmであるアルミニウム合金熱延板とされる。次いで、冷間圧延されて板厚が3mm以下の冷延板とされる。この際、冷間圧延の中途において1回または2回以上の中間焼鈍を選択的に行なっても良い。
In the present invention, the 7000 series aluminum alloy plate can be manufactured by a manufacturing method according to a normal manufacturing process. That is, an aluminum alloy hot-rolled sheet having a thickness of 1.5 to 5.0 mm is manufactured through normal manufacturing processes such as casting (DC casting or continuous casting), homogenization heat treatment, and hot rolling. The Subsequently, it is cold-rolled to obtain a cold-rolled sheet having a thickness of 3 mm or less. At this time, intermediate annealing may be selectively performed once or twice in the middle of cold rolling.
(溶解、鋳造冷却速度)
先ず、溶解、鋳造工程では、上記7000系成分組成範囲内に溶解調整されたアルミニウム合金溶湯を、連続鋳造法、半連続鋳造法(DC鋳造法)等の通常の溶解鋳造法を適宜選択して鋳造する。 (Dissolution, casting cooling rate)
First, in the melting and casting process, an ordinary molten casting method such as a continuous casting method or a semi-continuous casting method (DC casting method) is appropriately selected for the aluminum alloy melt adjusted within the above-mentioned 7000-based component composition range. Cast.
先ず、溶解、鋳造工程では、上記7000系成分組成範囲内に溶解調整されたアルミニウム合金溶湯を、連続鋳造法、半連続鋳造法(DC鋳造法)等の通常の溶解鋳造法を適宜選択して鋳造する。 (Dissolution, casting cooling rate)
First, in the melting and casting process, an ordinary molten casting method such as a continuous casting method or a semi-continuous casting method (DC casting method) is appropriately selected for the aluminum alloy melt adjusted within the above-mentioned 7000-based component composition range. Cast.
(均質化熱処理)
次いで、前記鋳造されたアルミニウム合金鋳塊に、熱間圧延に先立って、均質化熱処理を施す。この均質化熱処理(均熱処理)は、組織の均質化、すなわち、鋳塊組織中の結晶粒内の偏析をなくすことを目的とする。 (Homogenization heat treatment)
Next, the cast aluminum alloy ingot is subjected to a homogenization heat treatment prior to hot rolling. The purpose of this homogenization heat treatment (soaking) is to homogenize the structure, that is, eliminate segregation in crystal grains in the ingot structure.
次いで、前記鋳造されたアルミニウム合金鋳塊に、熱間圧延に先立って、均質化熱処理を施す。この均質化熱処理(均熱処理)は、組織の均質化、すなわち、鋳塊組織中の結晶粒内の偏析をなくすことを目的とする。 (Homogenization heat treatment)
Next, the cast aluminum alloy ingot is subjected to a homogenization heat treatment prior to hot rolling. The purpose of this homogenization heat treatment (soaking) is to homogenize the structure, that is, eliminate segregation in crystal grains in the ingot structure.
但し、本発明では、製造する板の組織を、前記TEMにより観察される粒界と粒内の各析出物のZnとMgとの平均組成比として、構造材への成形加工性及び成形加工後の人工時効処理後の強度をともに向上させることが必要である。このために、均熱処理を2段或いは2回均熱工程で行うことが好ましい。通常の1回あるいは1段の均熱では、前記調質処理後に室温時効した後の板組織を、本発明で規定する粒界と粒内の各析出物のZnとMgとの平均組成比範囲内としにくくなる。
However, in the present invention, the structure of the plate to be produced is defined as an average composition ratio of Zn and Mg of the precipitates in the grain boundaries and the grains observed by the TEM, and after the molding processability to the structural material. It is necessary to improve both the strength after artificial aging treatment. For this reason, it is preferable to perform the soaking process in two or two soaking steps. In normal one-time or one-step soaking, the plate structure after aging at room temperature after the tempering treatment is defined as an average composition ratio range of Zn and Mg of grain precipitates and precipitates in the grains defined in the present invention. It becomes difficult to be inside.
2段均熱とは、1回目の均熱後に冷却はするものの、200℃以下までは冷却せず、より高温で冷却を停止した上で、その温度で維持した後に、そのままの温度か、より高温に再加熱した上で熱延を開始する。これに対して、2回均熱とは、1回目の均熱後に、一旦室温を含む200℃以下の温度まで冷却し、更に、再加熱し、その温度で一定時間維持した後に、熱延を開始する。
Two-stage soaking means cooling after the first soaking, but it is not cooled to 200 ° C. or lower, and after stopping the cooling at a higher temperature, after maintaining at that temperature, Hot rolling is started after reheating to a high temperature. On the other hand, after the first soaking, the two-time soaking is once cooled to a temperature of 200 ° C. or less including room temperature, reheated and maintained at that temperature for a certain period of time. Start.
これら2段或いは2回均熱工程における1段目或いは1回目の均熱工程においては、Zn系化合物や遷移元素系の化合物を微細分散させて、構造材への成形性に影響する化合物の微細化を狙い、2段目或いは2回目の均熱工程においては、Zn、Mg、Cuの固溶を促進する。これによって、前記TEMにより観察される粒界と粒内の各析出物のZnとMgとの平均組成比とする。
In the first or first soaking step in these two or two soaking steps, a Zn compound or a transition element compound is finely dispersed to finely affect the compound that affects the moldability to the structural material. In the second or second soaking step, solid solution of Zn, Mg, and Cu is promoted. Thus, the average composition ratio of Zn and Mg of the precipitates in the grain boundaries and grains observed by the TEM is obtained.
このために、1段目或いは1回目の均熱温度を400~450℃、好ましくは400~440℃に制御する。この温度範囲に鋳塊を加熱、保持する。この均熱温度が400℃未満では前記化合物の十分な微細化効果が得られない。また、一方で450℃を超えると、前記化合物が粗大化してしまう。これら1段目或いは1回目の均熱処理の保持時間は1~8時間程度で良い。
For this purpose, the soaking temperature in the first stage or the first time is controlled to 400 to 450 ° C., preferably 400 to 440 ° C. The ingot is heated and held in this temperature range. When the soaking temperature is less than 400 ° C., a sufficient effect of miniaturizing the compound cannot be obtained. On the other hand, when it exceeds 450 ° C., the compound becomes coarse. The holding time of the first or first soaking may be about 1 to 8 hours.
また、2段目或いは2回目の均熱処理温度を450℃~固相線温度、好ましくは470℃~固相線温度に制御する。この温度範囲に鋳塊を加熱、保持することによって、前記化合物の固溶を促進させることができる。この均熱温度が450℃未満では、これらの元素の固溶が十分に得られない。また、一方で固相線温度を超えると、部分溶融が起こり、機械的特性が劣化するので、上限は固相線温度以下とする。これら2段目或いは2回目の均熱時の保持時間は1~8時間程度で良い。
Further, the second or second soaking temperature is controlled to 450 ° C. to the solidus temperature, preferably 470 ° C. to the solidus temperature. The solid solution of the compound can be promoted by heating and holding the ingot in this temperature range. If this soaking temperature is less than 450 ° C., sufficient dissolution of these elements cannot be obtained. On the other hand, if the solidus temperature is exceeded, partial melting occurs and the mechanical properties deteriorate, so the upper limit is made the solidus temperature or lower. The holding time during the second or second soaking may be about 1 to 8 hours.
(熱間圧延)
熱間圧延は、熱延開始温度が固相線温度を超える条件では、バーニングが起こるため熱延自体が困難となる。また、熱延開始温度が350℃未満では熱延時の荷重が高くなりすぎ、熱延自体が困難となる。したがって、熱延開始温度は350℃~固相線温度の範囲から選択して熱間圧延し、2~7mm程度の板厚の熱延板とする。この熱延板の冷間圧延前の焼鈍 (荒鈍) の必要はない。 (Hot rolling)
In the hot rolling, the hot rolling itself becomes difficult because burning occurs under conditions where the hot rolling start temperature exceeds the solidus temperature. On the other hand, when the hot rolling start temperature is less than 350 ° C., the load during hot rolling becomes too high, and the hot rolling itself becomes difficult. Therefore, the hot rolling start temperature is selected from the range of 350 ° C. to the solidus temperature and hot rolled to obtain a hot rolled sheet having a thickness of about 2 to 7 mm. There is no need for annealing (roughening) of the hot-rolled sheet before cold rolling.
熱間圧延は、熱延開始温度が固相線温度を超える条件では、バーニングが起こるため熱延自体が困難となる。また、熱延開始温度が350℃未満では熱延時の荷重が高くなりすぎ、熱延自体が困難となる。したがって、熱延開始温度は350℃~固相線温度の範囲から選択して熱間圧延し、2~7mm程度の板厚の熱延板とする。この熱延板の冷間圧延前の焼鈍 (荒鈍) の必要はない。 (Hot rolling)
In the hot rolling, the hot rolling itself becomes difficult because burning occurs under conditions where the hot rolling start temperature exceeds the solidus temperature. On the other hand, when the hot rolling start temperature is less than 350 ° C., the load during hot rolling becomes too high, and the hot rolling itself becomes difficult. Therefore, the hot rolling start temperature is selected from the range of 350 ° C. to the solidus temperature and hot rolled to obtain a hot rolled sheet having a thickness of about 2 to 7 mm. There is no need for annealing (roughening) of the hot-rolled sheet before cold rolling.
(冷間圧延)
冷間圧延では、上記熱延板を圧延して、1~3mm程度の所望の最終板厚の冷延板 (コイルも含む) に製作する。冷間圧延パス間で中間焼鈍を行っても良い。 (Cold rolling)
In cold rolling, the hot-rolled sheet is rolled into a cold-rolled sheet (including a coil) having a desired final thickness of about 1 to 3 mm. Intermediate annealing may be performed between cold rolling passes.
冷間圧延では、上記熱延板を圧延して、1~3mm程度の所望の最終板厚の冷延板 (コイルも含む) に製作する。冷間圧延パス間で中間焼鈍を行っても良い。 (Cold rolling)
In cold rolling, the hot-rolled sheet is rolled into a cold-rolled sheet (including a coil) having a desired final thickness of about 1 to 3 mm. Intermediate annealing may be performed between cold rolling passes.
(溶体化処理)
冷間圧延後は調質として溶体化処理を行う。これによって、前記TEMにより観察される、特に粒界析出物(室温時効析出物)のZnとMgとの平均組成比とする。この溶体化処理については、通常の連続熱処理ラインによる加熱,冷却でよく、特に限定はされない。ただ、各元素の十分な固溶量を得ることや結晶粒の微細化のためには、450℃~固相線温度以下、好ましくは480~550℃の溶体化処理温度で、保持時間は所定の溶体化処理温度に到達後、2秒か3秒以上、30分以下の範囲で行う。 (Solution treatment)
After cold rolling, solution treatment is performed as a tempering. Thus, the average composition ratio of Zn and Mg in the grain boundary precipitates (room temperature aging precipitates) observed by the TEM is obtained. The solution treatment is not particularly limited and may be heating and cooling using a normal continuous heat treatment line. However, in order to obtain a sufficient solid solution amount of each element and refinement of crystal grains, the holding time is predetermined at a solution treatment temperature of 450 ° C. to a solidus temperature, preferably 480 to 550 ° C. After reaching the solution treatment temperature, it is carried out in the range of 2 to 3 seconds and 30 minutes or less.
冷間圧延後は調質として溶体化処理を行う。これによって、前記TEMにより観察される、特に粒界析出物(室温時効析出物)のZnとMgとの平均組成比とする。この溶体化処理については、通常の連続熱処理ラインによる加熱,冷却でよく、特に限定はされない。ただ、各元素の十分な固溶量を得ることや結晶粒の微細化のためには、450℃~固相線温度以下、好ましくは480~550℃の溶体化処理温度で、保持時間は所定の溶体化処理温度に到達後、2秒か3秒以上、30分以下の範囲で行う。 (Solution treatment)
After cold rolling, solution treatment is performed as a tempering. Thus, the average composition ratio of Zn and Mg in the grain boundary precipitates (room temperature aging precipitates) observed by the TEM is obtained. The solution treatment is not particularly limited and may be heating and cooling using a normal continuous heat treatment line. However, in order to obtain a sufficient solid solution amount of each element and refinement of crystal grains, the holding time is predetermined at a solution treatment temperature of 450 ° C. to a solidus temperature, preferably 480 to 550 ° C. After reaching the solution treatment temperature, it is carried out in the range of 2 to 3 seconds and 30 minutes or less.
溶体化処理後の平均冷却(降温)速度は、前記TEMにより観察される、特に粒界析出物(室温時効析出物)のZnとMgとの平均組成比とするために、10℃/s以上、好ましくは30℃/s以上、より好ましくは40℃/s以上の、できるだけ速い冷却速度にて行う。溶体化処理後の平均冷却(降温)速度が遅いと、粗大な粒界析出物が形成される結果、前記TEMにより観察される、特に粒界析出物(室温時効析出物)のZnとMgとの平均組成比とはなりにくい。
The average cooling (temperature decrease) rate after the solution treatment is 10 ° C./s or more in order to obtain an average composition ratio of Zn and Mg of the grain boundary precipitates (room temperature aging precipitates) observed by the TEM. The cooling rate is preferably as high as possible, preferably 30 ° C./s or higher, more preferably 40 ° C./s or higher. When the average cooling (cooling) rate after solution treatment is slow, coarse grain boundary precipitates are formed, and as a result, the grain boundary precipitates (room temperature aging precipitates) Zn and Mg are observed. It is difficult to achieve an average composition ratio.
このため、溶体化処理後の冷却には、ファンなどの空冷、ミスト、スプレー、浸漬等の水冷手段など、強制的な冷却手段を選択あるいは組み合わせて用いるか、室温~100℃までの温湯に焼き入れる。ちなみに、溶体化処理は基本的に1回のみであるが、室温時効硬化が進みすぎた場合などには、自動車部材への成形性の確保のため、溶体化処理や復元処理を前記好ましい条件にて再度施して、この進みすぎた室温時効硬化を一旦キャンセルしても良い。
For this reason, for cooling after the solution treatment, forced cooling means such as air cooling such as a fan, water cooling means such as mist, spray, and immersion are selected or combined, or they are baked in hot water from room temperature to 100 ° C. Put in. By the way, the solution treatment is basically only one time, but when the room temperature age hardening has progressed too much, the solution treatment and the restoration treatment are made the above-mentioned preferable conditions in order to ensure the moldability to the automobile member. It may be applied again, and this excessive room temperature age hardening may be canceled once.
そして、本発明のアルミニウム合金板は、素材として、自動車部材に成形加工され、自動車部材として組み立てられる。また、自動車部材に成形加工された後で、別途人工時効処理されて、自動車部材あるいは自動車車体とされる。
Then, the aluminum alloy plate of the present invention is molded into an automobile member as a material and assembled as an automobile member. In addition, after being molded into an automobile member, artificial aging treatment is separately performed to obtain an automobile member or an automobile body.
人工時効硬化処理:
本発明の7000系アルミニウム合金板は、構造材への成形加工後に人工時効硬化処理(以下、単に人工時効処理あるいは時効処理とも言う)によって、前記TEMにより観察される、特に粒内析出物(人工時効析出物)のZnとMgとの平均組成比とされ、自動車部材などの構造材としての所望の強度、0.2%耐力で380MPa以上、好ましくは400MPa以上とされる。
この人工時効処理を行う時点は、素材7000系アルミニウム合金板の自動車部材への成形加工後が好ましい。人工時効処理後の7000系アルミニウム合金板は、強度は高くなるものの、成形性は低下しており、自動車部材の形状の複雑化によっては成形できない場合も生じるからである。 Artificial age hardening treatment:
The 7000 series aluminum alloy plate of the present invention is observed by the TEM by an artificial age hardening treatment (hereinafter also simply referred to as artificial aging treatment or aging treatment) after forming into a structural material. The average composition ratio of Zn and Mg in the aging precipitate) is set to 380 MPa or more, preferably 400 MPa or more at a desired strength and 0.2% proof stress as a structural material such as an automobile member.
The time point at which this artificial aging treatment is performed is preferably after the forming processing of the material 7000 series aluminum alloy plate to the automobile member. This is because the 7000 series aluminum alloy plate after the artificial aging treatment has high strength but has low formability, and may not be formed depending on the complexity of the shape of the automobile member.
本発明の7000系アルミニウム合金板は、構造材への成形加工後に人工時効硬化処理(以下、単に人工時効処理あるいは時効処理とも言う)によって、前記TEMにより観察される、特に粒内析出物(人工時効析出物)のZnとMgとの平均組成比とされ、自動車部材などの構造材としての所望の強度、0.2%耐力で380MPa以上、好ましくは400MPa以上とされる。
この人工時効処理を行う時点は、素材7000系アルミニウム合金板の自動車部材への成形加工後が好ましい。人工時効処理後の7000系アルミニウム合金板は、強度は高くなるものの、成形性は低下しており、自動車部材の形状の複雑化によっては成形できない場合も生じるからである。 Artificial age hardening treatment:
The 7000 series aluminum alloy plate of the present invention is observed by the TEM by an artificial age hardening treatment (hereinafter also simply referred to as artificial aging treatment or aging treatment) after forming into a structural material. The average composition ratio of Zn and Mg in the aging precipitate) is set to 380 MPa or more, preferably 400 MPa or more at a desired strength and 0.2% proof stress as a structural material such as an automobile member.
The time point at which this artificial aging treatment is performed is preferably after the forming processing of the material 7000 series aluminum alloy plate to the automobile member. This is because the 7000 series aluminum alloy plate after the artificial aging treatment has high strength but has low formability, and may not be formed depending on the complexity of the shape of the automobile member.
この人工時効処理の温度や時間の条件は、所望の強度や素材の7000系アルミニウム合金板の強度、あるいは室温時効の進行程度などから、一般的な人工時効条件(T6、T7)の範囲で決定される。ちなみに、人工時効処理の条件を例示すると、1段の時効処理であれば、100~150℃での時効処理を12~36時間(過時効領域を含む)行う。また、2段の工程においては、1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の範囲(過時効領域を含む)から選択する。
The temperature and time conditions of this artificial aging treatment are determined within the range of general artificial aging conditions (T6, T7) from the desired strength, the strength of the 7000 series aluminum alloy plate of the material, or the progress of room temperature aging. Is done. Incidentally, as an example of the conditions for artificial aging treatment, the aging treatment at 100 to 150 ° C. is performed for 12 to 36 hours (including the overaging region) in the case of one-stage aging treatment. In the two-stage process, the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or longer, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for five hours or longer (overaging region). Select from).
ただ、この人工時効処理条件の範囲の中でも、前記TEMにより観察される、特に粒内析出物(人工時効析出物)のZnとMgとの平均組成比として、BH後の強度を、構造材として必要な380MPa以上、好ましくは400MPa以上に保証できる好ましい条件がある。この条件とは、前記1段の人工時効工程では人工時効処理時の昇温速度、あるいは2段の人工時効処理では1段目の人工時効処理時の昇温速度を、30℃/分以下の、できるだけ遅い昇温速度で行うことである。これによって、生成する粒内析出物(人工時効析出物)のZn含有量を低減できる一方で、マトリックス中のZn量を確保でき、規定するZnとMgとの平均組成比とすることができる。なお、上記2段目の昇温速度はBH後の強度に影響せず、30℃/分以上の効率的な昇温速度が選択される。なお、2段目の再加熱は、1段目の加熱温度での保持後、一旦室温まで冷却してから再加熱しても、保持している温度から連続的に再加熱しても、強度への影響に差はなく、どちらでも良い。
However, within the range of this artificial aging treatment condition, the strength after BH is used as the structural material, particularly as the average composition ratio of Zn and Mg in the intragranular precipitate (artificial aging precipitate) observed by the TEM. There are preferable conditions that can guarantee the required 380 MPa or more, preferably 400 MPa or more. This condition means that the heating rate during the artificial aging treatment in the one-stage artificial aging process or the heating rate during the first artificial aging treatment in the two-stage artificial aging treatment is 30 ° C./min or less. It is to carry out at the slowest possible heating rate. Thereby, while the Zn content of the produced intragranular precipitates (artificial aging precipitates) can be reduced, the amount of Zn in the matrix can be ensured and the average composition ratio of Zn and Mg can be obtained. The second stage temperature rise rate does not affect the strength after BH, and an efficient temperature rise rate of 30 ° C./min or more is selected. In addition, the second stage reheating can be performed after holding at the first stage heating temperature, after cooling to room temperature and then reheating, or by continuously reheating from the held temperature. There is no difference in the impact on either.
ここで、本発明において好ましい条件として規定する、粒内析出物のZnとMgとの平均組成比(Zn/Mg)における人工時効硬化処理の条件は、30℃/分の昇温速度で90℃まで加熱して3時間保持後、更に30℃/分の昇温速度で140℃まで加熱して8時間保持する2段階の特定条件としている。これは、素材7000系アルミニウム合金板の自動車部材への成形加工後の実際の人工時効処理において生成する、強度に影響する粒内析出物のZnとMgとの平均組成比との相関を図るためである。
Here, the conditions of the artificial age hardening treatment in the average composition ratio (Zn / Mg) of Zn and Mg of the intragranular precipitates defined as preferable conditions in the present invention are 90 ° C. at a temperature rising rate of 30 ° C./min. It is set as a two-stage specific condition of heating to 140 ° C. at a heating rate of 30 ° C./min and holding for 8 hours. This is for the purpose of correlating the average composition ratio of Zn and Mg of intragranular precipitates produced in the actual artificial aging treatment after forming the material 7000 series aluminum alloy plate into an automobile member. It is.
なお、素材7000系アルミニウム合金板の自動車部材への成形加工後の実際の人工時効処理の条件は、勿論種々異なる。しかし、前記1段のみの場合や、2段の場合の1段目の、各昇温速度さえ、30℃/分以下としてやれば、前記した好ましい範囲内の人工時効処理条件であれば、強度に影響する粒内析出物の生成量やZnとMgとの平均組成比に大差は無い。
しかも、本発明において規定する、粒内析出物のZnとMgとの平均組成比(Zn/Mg)における人工時効硬化処理条件における、30℃/分の昇温速度は、構造材として必要な380MPa以上の所望の強度を得る、最低の条件である。すなわち、前記した好ましい範囲内の人工時効処理条件であれば、この昇温速度が30℃/分未満と遅いほど、強度が高くなり、実際の自動車部材への成形加工後の人工時効処理において生成する粒内析出物のZnとMgとの平均組成比との相関が図れる。 Of course, the conditions of the actual artificial aging treatment after forming the material 7000 series aluminum alloy plate on the automobile member are variously different. However, in the case of only the first stage or in the first stage in the case of two stages, if each heating rate is set to 30 ° C./min or less, if the artificial aging treatment conditions are within the above preferred range, the strength There is no great difference in the amount of intragranular precipitates that affect the average particle size and the average composition ratio of Zn and Mg.
Moreover, the temperature increase rate of 30 ° C./min under the condition of artificial age hardening in the average composition ratio (Zn / Mg) of the intragranular precipitates defined in the present invention is 380 MPa, which is necessary for the structural material. This is the minimum condition for obtaining the above desired strength. In other words, if the artificial aging treatment conditions are within the above-mentioned preferred range, the slower the temperature increase rate is less than 30 ° C./min, the higher the strength becomes, and the artificial aging treatment is performed in the actual automobile member after forming. Correlation with the average composition ratio of Zn and Mg in the intragranular precipitates can be achieved.
しかも、本発明において規定する、粒内析出物のZnとMgとの平均組成比(Zn/Mg)における人工時効硬化処理条件における、30℃/分の昇温速度は、構造材として必要な380MPa以上の所望の強度を得る、最低の条件である。すなわち、前記した好ましい範囲内の人工時効処理条件であれば、この昇温速度が30℃/分未満と遅いほど、強度が高くなり、実際の自動車部材への成形加工後の人工時効処理において生成する粒内析出物のZnとMgとの平均組成比との相関が図れる。 Of course, the conditions of the actual artificial aging treatment after forming the material 7000 series aluminum alloy plate on the automobile member are variously different. However, in the case of only the first stage or in the first stage in the case of two stages, if each heating rate is set to 30 ° C./min or less, if the artificial aging treatment conditions are within the above preferred range, the strength There is no great difference in the amount of intragranular precipitates that affect the average particle size and the average composition ratio of Zn and Mg.
Moreover, the temperature increase rate of 30 ° C./min under the condition of artificial age hardening in the average composition ratio (Zn / Mg) of the intragranular precipitates defined in the present invention is 380 MPa, which is necessary for the structural material. This is the minimum condition for obtaining the above desired strength. In other words, if the artificial aging treatment conditions are within the above-mentioned preferred range, the slower the temperature increase rate is less than 30 ° C./min, the higher the strength becomes, and the artificial aging treatment is performed in the actual automobile member after forming. Correlation with the average composition ratio of Zn and Mg in the intragranular precipitates can be achieved.
下記表1に示すAl-Zn-Mg-Cu系成分組成の7000系アルミニウム合金冷延板を、規定する粒界と粒内の各析出物のZnとMgとの平均組成比(Zn/Mg)を種々変えて製造した。これら製造した冷延板について、この板を溶体化および焼入れ処理後に2週間室温時効させた際(T4)の、粒界析出物のZnとMgとの平均組成比や、加工硬化指数n値(10~15%)、強度、伸びなどの機械的特性を測定した。また、この2週間室温時効させた板を、更に人工時効硬化処理(T6)を行った後の、粒内析出物のZnとMgとの平均組成比や、強度などの機械的な特性と一般耐食性についても評価した。これらの結果を下記表2、3に示す。
The average composition ratio (Zn / Mg) of Zn and Mg of the precipitates in the grain boundary and grain within the 7000 series aluminum alloy cold-rolled sheet of the Al—Zn—Mg—Cu system component composition shown in Table 1 below. Were manufactured with various changes. About these manufactured cold-rolled sheets, when this sheet was aged at room temperature for 2 weeks after solution treatment and quenching treatment (T4), the average composition ratio of Zn and Mg of grain boundary precipitates and the work hardening index n value ( 10-15%), mechanical properties such as strength and elongation were measured. In addition, mechanical properties such as the average composition ratio and strength of the intragranular precipitates Zn and Mg after further performing artificial age hardening (T6) on the plate aged for 2 weeks at room temperature and general Corrosion resistance was also evaluated. These results are shown in Tables 2 and 3 below.
板の前記粒界と粒内の各析出物のZnとMgとの平均組成比(Zn/Mg)は、表1に示す成分組成とともに、表2、3に示す、鋳塊の均熱処理条件と、冷延板の溶体化処理後の平均冷却速度とを種々変えて制御した。
The average composition ratio (Zn / Mg) of Zn and Mg of the precipitates in the grain boundaries and grains within the plate is as shown in Tables 2 and 3 together with the component composition shown in Table 1 The average cooling rate after the solution treatment of the cold rolled sheet was variously controlled.
具体的には、各例とも共通して、下記表1に示す各成分組成の7000系アルミニウム合金溶湯をDC鋳造し、45mm厚み×220mm幅×145mm長さの鋳塊を得た。この鋳塊を表2の条件で2段均熱あるいは2回均熱を行った。2段均熱は1回目の均熱後に250℃まで冷却し、その温度で冷却を一旦停止した上で、2段目の均熱温度に再加熱および保持し、熱延開始温度まで冷却した上で熱延を開始した。2回均熱は、1回目の均熱後に、一旦室温まで冷却した上で、2回目の均熱温度に再加熱および保持し、熱延開始温度まで冷却した上で熱延を開始した。表2の1回のみの均熱処理は、一旦冷却した上での2回目の再加熱は行わず、通常通り、その均熱温度と時間保持した上で、熱延開始温度まで冷却して熱延を開始した。
Specifically, in common with each example, a 7000 series aluminum alloy molten metal having each component composition shown in Table 1 below was DC cast to obtain an ingot of 45 mm thickness × 220 mm width × 145 mm length. The ingot was subjected to two-stage soaking or twice soaking under the conditions shown in Table 2. After the first soaking, the second stage soaking is cooled to 250 ° C., once the cooling is stopped at that temperature, reheated and held at the second stage soaking temperature, and cooled to the hot rolling start temperature. The hot rolling was started. After the first soaking, the second soaking was once cooled to room temperature, reheated and held at the second soaking temperature, cooled to the hot rolling start temperature, and then started hot rolling. The soaking process of only one time in Table 2 does not perform the second reheating after cooling once, and keeps the soaking temperature and time as usual, and then cools to the hot rolling start temperature and performs hot rolling. Started.
これらの均熱処理後に、表2に示す開始温度で熱間圧延を行い、板厚5mmtの熱延板を製造した。この熱延板を、荒鈍処理を施さずに、2mmtまで冷間圧延を行った。この冷延板を、各例とも共通して500℃×1分の溶体化処理を施し、この溶体化処理後に強制空冷の仕方を変えて、平均冷却速度を種々変えて室温まで冷却し、T4調質材を得た。この溶体化処理後のアルミニウム合金板を、各例とも共通して2週間室温時効させた板から、板状試験片を採取して、前記粒界の析出物のZnとMgとの平均組成比(Zn/Mg)の測定と、加工硬化指数n値の測定、強度、伸びなどの機械的特性を以下の要領にて調査した。
After these soaking treatments, hot rolling was performed at a starting temperature shown in Table 2 to produce a hot rolled sheet having a thickness of 5 mm. This hot-rolled sheet was cold-rolled to 2 mmt without subjecting it to any roughening treatment. The cold-rolled sheet is subjected to a solution treatment at 500 ° C. for 1 minute in common with each example, and after this solution treatment, the method of forced air cooling is changed, and the average cooling rate is changed to various temperatures to cool to room temperature. A tempered material was obtained. The aluminum alloy plate after solution treatment was sampled from a plate aged at room temperature for 2 weeks in common with each example, and an average composition ratio of Zn and Mg of the precipitates at the grain boundaries was collected. Measurement of (Zn / Mg), measurement of work hardening index n value, mechanical properties such as strength and elongation were investigated as follows.
また、自動車部材への成形加工後の人工時効硬化処理を模擬して、前記2週間室温時効後のアルミニウム合金板を、T6処理として、更に表2、3に記載の1段目の昇温速度、時効温度で3時間保持後、この保持している温度から連続的に再加熱して30℃/分の昇温速度で140℃まで加熱して8時間保持する2段階での人工時効硬化処理を行った。
In addition, the artificial age-hardening treatment after forming the automobile member was simulated, and the aluminum alloy sheet after room temperature aging for the above two weeks was treated as T6 treatment, and further the first stage temperature increase rate shown in Tables 2 and 3 Then, after holding at the aging temperature for 3 hours, the artificial age hardening treatment is performed in two stages in which it is continuously reheated from the held temperature, heated to 140 ° C. at a heating rate of 30 ° C./min and held for 8 hours. Went.
なお、発明例の一部は、T6条件の違いによる影響を見るために、T6条件のみを敢えて変えた熱処理条件で行った。具体的には、表2の発明例18は、1段目は30℃/分の昇温速度で90℃まで加熱して3時間保持する条件で行った後、2段目を、30℃/分の昇温速度であるが、130℃まで加熱して12時間保持する条件で行った。また、表2の発明例19は、1段のみの人工時効処理で、昇温速度は30℃/分で行い、120℃まで加熱して24時間保持する条件で行った。
In addition, in order to see the influence by the difference in T6 conditions, a part of invention example was performed on the heat processing conditions which changed only T6 conditions. Specifically, Invention Example 18 in Table 2 was performed under the condition that the first stage was heated to 90 ° C. at a temperature increase rate of 30 ° C./min and held for 3 hours, and then the second stage was 30 ° C. / The heating rate was 1 minute, and the heating was performed up to 130 ° C. and held for 12 hours. Inventive example 19 in Table 2 was an artificial aging treatment with only one stage, and the temperature elevation rate was 30 ° C./min. The temperature was raised to 120 ° C. and maintained for 24 hours.
この人工時効硬化処理後のアルミニウム合金板の中央部から板状試験片を採取して、粒内の各析出物のZnとMgとの平均組成比(Zn/Mg)、機械的特性や耐食性も、以下の要領にて調査した。これらの結果を各々表2、3に示す。
A plate-shaped test piece is taken from the central part of the aluminum alloy plate after the artificial age hardening treatment, and the average composition ratio (Zn / Mg) of Zn and Mg of each precipitate in the grains, mechanical properties and corrosion resistance are also obtained. The investigation was conducted as follows. These results are shown in Tables 2 and 3, respectively.
(粒界析出物と粒内析出物の組成の測定)
60000倍のTEM-EDXを用い、前記した各要領にて、粒界析出物と粒内析出物とのZnとMgとの平均組成比を各々測定した。 (Measurement of composition of grain boundary precipitates and intragranular precipitates)
Using 60000 times TEM-EDX, the average composition ratios of Zn and Mg of the grain boundary precipitates and the intragranular precipitates were respectively measured in the manner described above.
60000倍のTEM-EDXを用い、前記した各要領にて、粒界析出物と粒内析出物とのZnとMgとの平均組成比を各々測定した。 (Measurement of composition of grain boundary precipitates and intragranular precipitates)
Using 60000 times TEM-EDX, the average composition ratios of Zn and Mg of the grain boundary precipitates and the intragranular precipitates were respectively measured in the manner described above.
(機械的特性)
各例とも機械的特性は、共通して、各板状試験片の圧延直角方向の室温引張試験を行い、0.2%耐力(MPa)、全伸び(%)を測定した。室温引張り試験はJIS2241(1980)に基づき、室温20℃で試験を行った。引張り速度は5mm/分で、試験片が破断するまで一定の速度で行った。 (Mechanical properties)
In each example, the mechanical properties were commonly measured by performing a room temperature tensile test in the direction perpendicular to the rolling direction of each plate-like specimen and measuring 0.2% proof stress (MPa) and total elongation (%). The room temperature tensile test was performed at a room temperature of 20 ° C. based on JIS2241 (1980). The tensile speed was 5 mm / min, and the test was performed at a constant speed until the test piece broke.
各例とも機械的特性は、共通して、各板状試験片の圧延直角方向の室温引張試験を行い、0.2%耐力(MPa)、全伸び(%)を測定した。室温引張り試験はJIS2241(1980)に基づき、室温20℃で試験を行った。引張り速度は5mm/分で、試験片が破断するまで一定の速度で行った。 (Mechanical properties)
In each example, the mechanical properties were commonly measured by performing a room temperature tensile test in the direction perpendicular to the rolling direction of each plate-like specimen and measuring 0.2% proof stress (MPa) and total elongation (%). The room temperature tensile test was performed at a room temperature of 20 ° C. based on JIS2241 (1980). The tensile speed was 5 mm / min, and the test was performed at a constant speed until the test piece broke.
(n値)
加工硬化指数n値は、前記人工時効硬化処理後の板状試験片を、JIS5号引張試験片(標点間距離50mm)として、圧延直角方向の室温引張試験を行い測定した。そして、降伏伸びの終点から真応力と真歪みを計算し、横軸を歪み、縦軸を応力とした対数目盛上にプロットし、測定点が表す直線の勾配を、公称ひずみ10%、15%の2点で計算して、n値(10~15%)とした。 (N value)
The work hardening index n value was measured by performing a room temperature tensile test in the direction perpendicular to the rolling direction, using the plate-like test piece after the artificial age hardening treatment as a JIS No. 5 tensile test piece (distance between gauge points 50 mm). Then, the true stress and true strain are calculated from the end point of yield elongation, plotted on a logarithmic scale with the horizontal axis being strain and the vertical axis being stress, and the gradient of the straight line represented by the measurement point is 10% or 15% of nominal strain. The n value (10 to 15%) was calculated from the two points.
加工硬化指数n値は、前記人工時効硬化処理後の板状試験片を、JIS5号引張試験片(標点間距離50mm)として、圧延直角方向の室温引張試験を行い測定した。そして、降伏伸びの終点から真応力と真歪みを計算し、横軸を歪み、縦軸を応力とした対数目盛上にプロットし、測定点が表す直線の勾配を、公称ひずみ10%、15%の2点で計算して、n値(10~15%)とした。 (N value)
The work hardening index n value was measured by performing a room temperature tensile test in the direction perpendicular to the rolling direction, using the plate-like test piece after the artificial age hardening treatment as a JIS No. 5 tensile test piece (distance between gauge points 50 mm). Then, the true stress and true strain are calculated from the end point of yield elongation, plotted on a logarithmic scale with the horizontal axis being strain and the vertical axis being stress, and the gradient of the straight line represented by the measurement point is 10% or 15% of nominal strain. The n value (10 to 15%) was calculated from the two points.
(粒界腐食感受性)
一般的な耐食性評価のために、旧JIS-W1103の規定に準じた粒界腐食感受性試験を、前記人工時効硬化処理後の板状試験片(試験片3個)に対して行った。試験条件は、試験片を硝酸水溶液(30質量%)に室温で1分間浸漬した後、水酸化ナトリウム水溶液(5質量%)に40℃で20秒浸漬した後、硝酸水溶液(30質量%)に室温で1分間浸漬することによって試験片の表面を洗浄した。その後、塩化ナトリウム水溶液(5質量%)に浸漬した状態で、1mA/cm2の電流密度の電流を24時間流した後、試料を引き上げ、その後、試験片の断面を切断・研磨し、光学顕微鏡を用いて、試料表面からの腐食深さを測定した。倍率は×100 とし、腐食深さが200μm以下までを軽微な腐食として「○」と評価した。また、200μmを超える場合を大きな腐食として「×」と評価した。 (Intergranular corrosion sensitivity)
For general corrosion resistance evaluation, a grain boundary corrosion susceptibility test in accordance with the provisions of the former JIS-W1103 was performed on the plate-like test pieces (three test pieces) after the artificial age hardening treatment. The test condition was that the test piece was immersed in an aqueous nitric acid solution (30% by mass) for 1 minute at room temperature, then immersed in an aqueous sodium hydroxide solution (5% by mass) at 40 ° C. for 20 seconds, and then immersed in an aqueous nitric acid solution (30% by mass). The surface of the test piece was cleaned by immersion for 1 minute at room temperature. Thereafter, a current having a current density of 1 mA / cm 2 was allowed to flow for 24 hours in a state immersed in an aqueous sodium chloride solution (5% by mass), and then the sample was pulled up, and then the cross section of the test piece was cut and polished. Was used to measure the depth of corrosion from the sample surface. The magnification was x100, and a corrosion depth of 200 μm or less was evaluated as “◯” as minor corrosion. Moreover, the case where it exceeded 200 micrometers was evaluated as "x" as big corrosion.
一般的な耐食性評価のために、旧JIS-W1103の規定に準じた粒界腐食感受性試験を、前記人工時効硬化処理後の板状試験片(試験片3個)に対して行った。試験条件は、試験片を硝酸水溶液(30質量%)に室温で1分間浸漬した後、水酸化ナトリウム水溶液(5質量%)に40℃で20秒浸漬した後、硝酸水溶液(30質量%)に室温で1分間浸漬することによって試験片の表面を洗浄した。その後、塩化ナトリウム水溶液(5質量%)に浸漬した状態で、1mA/cm2の電流密度の電流を24時間流した後、試料を引き上げ、その後、試験片の断面を切断・研磨し、光学顕微鏡を用いて、試料表面からの腐食深さを測定した。倍率は×100 とし、腐食深さが200μm以下までを軽微な腐食として「○」と評価した。また、200μmを超える場合を大きな腐食として「×」と評価した。 (Intergranular corrosion sensitivity)
For general corrosion resistance evaluation, a grain boundary corrosion susceptibility test in accordance with the provisions of the former JIS-W1103 was performed on the plate-like test pieces (three test pieces) after the artificial age hardening treatment. The test condition was that the test piece was immersed in an aqueous nitric acid solution (30% by mass) for 1 minute at room temperature, then immersed in an aqueous sodium hydroxide solution (5% by mass) at 40 ° C. for 20 seconds, and then immersed in an aqueous nitric acid solution (30% by mass). The surface of the test piece was cleaned by immersion for 1 minute at room temperature. Thereafter, a current having a current density of 1 mA / cm 2 was allowed to flow for 24 hours in a state immersed in an aqueous sodium chloride solution (5% by mass), and then the sample was pulled up, and then the cross section of the test piece was cut and polished. Was used to measure the depth of corrosion from the sample surface. The magnification was x100, and a corrosion depth of 200 μm or less was evaluated as “◯” as minor corrosion. Moreover, the case where it exceeded 200 micrometers was evaluated as "x" as big corrosion.
表1、2から明らかなように、各発明例1~19は、本発明アルミニウム合金組成範囲内であり、前記した好ましい製造条件の範囲内で製造されている。
As is apparent from Tables 1 and 2, Invention Examples 1 to 19 are within the composition range of the aluminum alloy of the present invention, and are manufactured within the range of the preferable manufacturing conditions described above.
この結果、この板を溶体化および焼入れ処理後に室温時効させた(調質T4)の組織において、60000倍の透過型電子顕微鏡にて観察される粒界析出物のZnとMgとの平均組成比(Zn/Mg)が0.5~3.0の範囲である。また、前記調質T4の板を更に前記2段階での人工時効硬化処理した(調質T6)の板の組織において、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であり、本発明の組織規定を満たしている。
As a result, the average composition ratio of Zn and Mg of grain boundary precipitates observed with a transmission electron microscope of 60000 times in the structure of the tempered T4 which was aged at room temperature after solution treatment and quenching treatment. (Zn / Mg) is in the range of 0.5 to 3.0. Further, in the structure of the plate of the tempered T4 further subjected to the artificial age hardening treatment (tempered T6) in the two stages, Zn and intragranular precipitates observed with a transmission electron microscope of 60000 times The average composition ratio (Zn / Mg) with Mg is in the range of 1.5 to 3.5, which satisfies the structure provision of the present invention.
このため、2週間の室温時効後であっても、成形性として必要な加工硬化指数n値0.22以上を満たし、延性に優れ、構造材への成形加工性に優れている。これと同時に、室温時効後であってもBH性に優れており、強度が高い。組成が[Zn]≧-0.3[Mg]+4.5を満足する発明例は、人工時効硬化処理後の(調質T6の)0.2%耐力が構造材として必要な380MPa以上であり、 [Zn]≧-0.5[Mg]+5.75を満足する場合には、人工時効硬化処理後の0.2%耐力がより高くなって430MPa以上である。
For this reason, even after 2 weeks of room temperature aging, the work hardening index n value 0.22 or more required as moldability is satisfied, the ductility is excellent, and the moldability to a structural material is excellent. At the same time, even after room temperature aging, the BH property is excellent and the strength is high. An example of the invention satisfying the composition [Zn] ≧ −0.3 [Mg] +4.5 has a 0.2% proof stress (of tempered T6) after the artificial age hardening treatment is 380 MPa or more which is necessary as a structural material. When [Zn] ≧ −0.5 [Mg] +5.75 is satisfied, the 0.2% proof stress after the artificial age hardening is higher and is 430 MPa or more.
ちなみに、T6条件の違いによる影響を見るためにT6条件のみを変えた、発明例5、18、19同士の比較では、組織や特性において細かい数値の違いはあるものの、粒内析出物のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲である。また、人工時効硬化処理後の0.2%耐力が同じ420MPaレベルであり、耐食性が良いことに変わりはない。したがって、段落0067で記載した、人工時効処理の温度や時間の好適な範囲の意義が裏付けられる。
By the way, in the comparison between Invention Examples 5, 18, and 19 in which only the T6 condition was changed in order to see the influence due to the difference in the T6 condition, although there was a small numerical difference in the structure and characteristics, The average composition ratio with Mg (Zn / Mg) is in the range of 1.5 to 3.5. Moreover, the 0.2% yield strength after the artificial age hardening treatment is the same 420 MPa level, and the corrosion resistance is still good. Therefore, the significance of the suitable range of the temperature and time of the artificial aging treatment described in paragraph 0067 is supported.
これに対して、表3の比較例20~32は、合金組成が、表1の番号で17~29であり、本発明範囲から外れている。
On the other hand, Comparative Examples 20 to 32 in Table 3 have an alloy composition of 17 to 29 as shown in Table 1, which is outside the scope of the present invention.
表3の比較例20、21は、合金組成が表1の番号で17、18であり、[Zn]、[Mg]は各々規定範囲内であるが、ZnとMgとのバランス式である、[Zn]≧-0.3[Mg]+4.5や[Zn]≧-0.5[Mg]+5.75の関係を両方満足していない。このため、好ましい製造条件内で製造されているものの、前記析出物組成比を満たさず、室温時効後の加工硬化指数n値(10~15%)は0.21~0.22レベルだが、人工時効硬化処理後の0.2%耐力が高くても329MPa程度と低すぎ、成形加工性と強度とを兼備できていない。
In Comparative Examples 20 and 21 in Table 3, the alloy compositions are numbers 17 and 18 in Table 1, and [Zn] and [Mg] are within the specified ranges, respectively, but are balanced expressions of Zn and Mg. Both [Zn] ≧ −0.3 [Mg] +4.5 and [Zn] ≧ −0.5 [Mg] +5.75 are not satisfied. For this reason, although it is manufactured within preferable manufacturing conditions, the composition ratio of precipitates is not satisfied, and the work hardening index n value (10 to 15%) after room temperature aging is 0.21 to 0.22 level. Even if the 0.2% yield strength after the age hardening treatment is high, it is too low at about 329 MPa, and it does not have both moldability and strength.
表2の発明例のうちでも、ZnとMgとのバランス式のうち、[Zn]≧-0.3[Mg]+4.5は満たすが、[Zn]≧-0.5[Mg]+5.75の方を満たさない、合金組成が表1の番号で1~4、6、8の、発明例1~5、7、9のT6での0.2%耐力は391~429MPaレベルである。これは、これらバランス式を両方満足する他の発明例の、T6での0.2%耐力が431~459MPaレベルであるのに比して、相対的に低い。したがって、これらの例から、Zn含有量を低めに抑制するとともに、Mg含有量を多めにする、前記バランス式の意義が裏付けられる。
Among the inventive examples in Table 2, among the balance formulas of Zn and Mg, [Zn] ≧ −0.3 [Mg] +4.5 is satisfied, but [Zn] ≧ −0.5 [Mg] +5. The 0.2% proof stress at T6 of Invention Examples 1 to 5, 7, and 8 having the alloy composition of 1 to 4, 6, and 8 with the numbers of Table 1 that do not satisfy 75 is 391 to 429 MPa level. This is relatively low as compared with the case where the 0.2% proof stress at T6 is 431 to 459 MPa level in other invention examples satisfying both of these balance equations. Therefore, these examples support the significance of the balance formula that suppresses the Zn content to a low level and increases the Mg content.
表3の比較例22~24は合金組成が表1の番号で19~21であり、Mgが下限を外れて少なすぎる。このため、前記ZnとMgとのバランス式を満足し、好ましい製造条件内で製造されていても、特に粒内析出物の組成比Zn/Mgが下限を外れ、室温時効後の加工硬化指数n値は0.21レベルだが、人工時効硬化処理後の0.2%耐力が高くても353MPa程度と低すぎ、成形加工性と強度とを兼備できていない。
In Comparative Examples 22 to 24 in Table 3, the alloy compositions are 19 to 21 with the numbers in Table 1, and Mg is too small beyond the lower limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value is 0.21 level, even if the 0.2% proof stress after the artificial age hardening treatment is high, it is too low at about 353 MPa, and it does not have both moldability and strength.
比較例25~28は合金組成が表1の番号で22~25であり、Mgが上限を外れて多すぎる。このため、前記ZnとMgとのバランス式を満足し、好ましい製造条件内で製造されていても、特に粒内析出物の組成比Zn/Mgが下限を外れ、室温時効後の加工硬化指数n値(10~15%)は0.22~0.23レベルだが、人工時効硬化処理後の0.2%耐力が高くても369MPa程度と低すぎ、成形加工性と強度とを兼備できていない。
Comparative Examples 25 to 28 have an alloy composition of 22 to 25 as shown in Table 1, and Mg is too much outside the upper limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value (10-15%) is 0.22 to 0.23 level, even if the 0.2% proof stress after artificial age hardening is high, it is too low at around 369 MPa, and it does not have both moldability and strength. .
比較例29、30は合金組成が表1の番号で26、27であり、Znが上限を外れて多すぎる。このため、前記ZnとMgとのバランス式を満足し、好ましい製造条件内で製造されていても、特に粒内析出物の組成比Zn/Mgが下限を外れ、室温時効後の加工硬化指数n値(10~15%)は0.22~0.23レベルだが、人工時効硬化処理後の0.2%耐力が高くても362MPa程度と低すぎ、成形加工性と強度とを兼備できていない。また、耐食性も劣る。
Comparative Examples 29 and 30 have alloy compositions of numbers 26 and 27 in Table 1, and Zn is too much outside the upper limit. For this reason, even if the balance formula of Zn and Mg is satisfied and manufactured within the preferable manufacturing conditions, the composition ratio Zn / Mg of the intragranular precipitate is outside the lower limit, and the work hardening index n after aging at room temperature. Although the value (10-15%) is 0.22 to 0.23 level, even if the 0.2% yield strength after artificial age hardening is high, it is too low at around 362 MPa, and it does not have both moldability and strength. . Moreover, corrosion resistance is also inferior.
比較例31は合金組成が表1の番号で28であり、Cuが下限を外れる。このため、前記ZnとMgとのバランス式を満足し、好ましい製造条件内で製造され、前記析出物組成比を満たし、室温時効後の加工硬化指数n値(10~15%)も0.23レベルで、人工時効硬化処理後の0.2%耐力も448MPaレベルで、成形加工性と強度とを兼備できている。しかし、致命的には耐食性が劣る。
Comparative Example 31 has an alloy composition of 28 as shown in Table 1, and Cu is out of the lower limit. For this reason, the balance formula of Zn and Mg is satisfied, manufactured within preferable manufacturing conditions, satisfies the precipitate composition ratio, and has a work hardening index n value (10 to 15%) after aging at room temperature of 0.23. In terms of level, the 0.2% proof stress after the artificial age hardening treatment is also at the 448 MPa level, and it has both moldability and strength. However, it is fatally inferior in corrosion resistance.
比較例32は合金組成が表1の番号で29であり、Cuが上限を外れる。このため、前記ZnとMgとのバランス式を満足し、好ましい製造条件内で製造され、前記析出物組成比を満たすが、室温時効後の加工硬化指数n値(10~15%)が0.209と低く、人工時効硬化処理後の0.2%耐力は456MPaレベルだが、成形加工性と強度とを兼備できていない。
Comparative Example 32 has an alloy composition of 29 in Table 1 and Cu is out of the upper limit. For this reason, the balance formula of Zn and Mg is satisfied, and it is manufactured within preferable manufacturing conditions and satisfies the precipitate composition ratio, but the work hardening index n value (10 to 15%) after aging at room temperature is 0.00. It is as low as 209, and the 0.2% proof stress after artificial age hardening is at the level of 456 MPa, but it does not have both moldability and strength.
表3の比較例33~37は、表1の合金番号1の発明例アルミニウム合金を用いているものの、好ましい製造条件範囲から外れて製造されている。
比較例33は1回目の均熱温度が低すぎる。
比較例34は2回目の均熱温度が低すぎる。
比較例35は溶体化処理後の平均冷却速度が遅すぎる。
比較例36、37は1回のみの均熱処理である。 Comparative Examples 33 to 37 in Table 3 are manufactured out of the preferable manufacturing condition range, although the invention example aluminum alloy of Alloy No. 1 in Table 1 is used.
In Comparative Example 33, the first soaking temperature is too low.
In Comparative Example 34, the second soaking temperature is too low.
In Comparative Example 35, the average cooling rate after the solution treatment is too slow.
Comparative Examples 36 and 37 are only one-time heat treatment.
比較例33は1回目の均熱温度が低すぎる。
比較例34は2回目の均熱温度が低すぎる。
比較例35は溶体化処理後の平均冷却速度が遅すぎる。
比較例36、37は1回のみの均熱処理である。 Comparative Examples 33 to 37 in Table 3 are manufactured out of the preferable manufacturing condition range, although the invention example aluminum alloy of Alloy No. 1 in Table 1 is used.
In Comparative Example 33, the first soaking temperature is too low.
In Comparative Example 34, the second soaking temperature is too low.
In Comparative Example 35, the average cooling rate after the solution treatment is too slow.
Comparative Examples 36 and 37 are only one-time heat treatment.
このため、これら均熱処理条件が好ましい範囲から外れた比較例は、粒界析出物の組成比Zn/Mgか、粒内析出物の組成比Zn/Mgかを満たさず、室温時効後の加工硬化指数n値(10~15%)が0.22未満となって延性や構造材への成形加工性が劣るか、人工時効硬化処理後の0.2%耐力も340MPa未満かと低くなって、成形加工性と強度とを兼備できていない。
For this reason, the comparative example in which these soaking conditions deviate from the preferred range does not satisfy the compositional ratio Zn / Mg of grain boundary precipitates or the composition ratio Zn / Mg of intragranular precipitates, and work hardening after aging at room temperature. The index n value (10 to 15%) is less than 0.22 and the ductility and molding processability to structural materials are inferior, or the 0.2% proof stress after artificial age hardening is less than 340 MPa. It does not have both workability and strength.
以上の結果から、本発明アルミニウム合金板が高強度と高延性(成形性)そして耐SCC性を兼備するための本発明各要件の臨界的な意義が裏付けられる。
The above results support the critical significance of the requirements of the present invention for the aluminum alloy sheet of the present invention to have both high strength, high ductility (formability) and SCC resistance.
本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは当業者にとって明らかである。
本出願は、2014年3月17日出願の日本特許出願(特願2014-053702)に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Mar. 17, 2014 (Japanese Patent Application No. 2014-053702), the contents of which are incorporated herein by reference.
本出願は、2014年3月17日出願の日本特許出願(特願2014-053702)に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Mar. 17, 2014 (Japanese Patent Application No. 2014-053702), the contents of which are incorporated herein by reference.
以上説明したように、本発明は、室温時効後であっても、強度と成形性、耐食性とを兼備した自動車部材用7000系アルミニウム合金板を提供できる。したがって、本発明は車体軽量化に寄与する、フレーム、ピラーなどの自動車構造材や、これ以外の他の用途の構造材などにも好適である。
As described above, the present invention can provide a 7000 series aluminum alloy plate for automobile members having strength, formability, and corrosion resistance even after aging at room temperature. Therefore, the present invention is also suitable for automobile structural materials such as frames and pillars that contribute to weight reduction of the vehicle body, and structural materials for other uses.
Claims (3)
- 質量%で、Zn:3.0~6.0%、Mg:2.5~4.5%、Cu:0.05~0.5%を各々含み、かつZnの含有量[Zn]とMgの含有量[Mg]とが [Zn]≧-0.3[Mg]+4.5を満足する関係にあり、残部がAlおよび不可避的不純物からなる組成のAl-Zn-Mg系アルミニウム合金板であって、この板を溶体化および焼入れ処理後に室温時効させた組織において、60000倍の透過型電子顕微鏡にて観察される粒界析出物のZnとMgとの平均組成比(Zn/Mg)が0.5~3.0の範囲であり、前記溶体化および焼入れ処理後に室温時効させた板を、
(I)1段目の熱処理温度が70~100℃の範囲で2時間以上、2段目の熱処理温度が100~170℃の範囲で5時間以上の2段の人工時効処理、
或いは、
(II)熱処理温度が100~150℃の範囲で12~36時間の1段の人工時効処理
のいずれか一方を行った後の板の組織において、60000倍の透過型電子顕微鏡にて観察される粒内析出物のZnとMgとの平均組成比(Zn/Mg)が1.5~3.5の範囲であることを特徴とする構造材用アルミニウム合金板。 In mass%, Zn: 3.0-6.0%, Mg: 2.5-4.5%, Cu: 0.05-0.5%, respectively, and Zn content [Zn] and Mg The content [Mg] of the Al—Zn—Mg-based aluminum alloy plate having a composition satisfying [Zn] ≧ −0.3 [Mg] +4.5, the balance being Al and inevitable impurities. In the structure in which this plate was aged at room temperature after solution treatment and quenching treatment, the average composition ratio (Zn / Mg) of Zn and Mg of grain boundary precipitates observed with a transmission electron microscope of 60000 times A range of 0.5 to 3.0, and a plate aged at room temperature after the solution treatment and quenching treatment,
(I) Two-stage artificial aging treatment in which the first-stage heat treatment temperature is in the range of 70 to 100 ° C. for 2 hours or more, and the second-stage heat treatment temperature is in the range of 100 to 170 ° C. for 5 hours or more.
Or
(II) The structure of the plate after one of the one-step artificial aging treatments in the range of 100 to 150 ° C. for 12 to 36 hours is observed with a transmission electron microscope of 60000 times An aluminum alloy plate for a structural material, wherein an average composition ratio (Zn / Mg) of Zn and Mg in the intragranular precipitate is in the range of 1.5 to 3.5. - 前記アルミニウム合金板が、更に、下記(a)及び(b)の少なくとも一方を含む請求項1に記載の構造材用アルミニウム合金板。
(a)質量%で、Zr:0.05~0.3%、Mn:0.1~1.5%、Cr:0.05~0.3%、Sc:0.05~0.3%の1種又は2種以上
(b)質量%で、Ag:0.01~0.2%、Sn:0.001~0.1%の1種又は2種 The aluminum alloy plate for a structural material according to claim 1, wherein the aluminum alloy plate further includes at least one of the following (a) and (b).
(A) By mass, Zr: 0.05 to 0.3%, Mn: 0.1 to 1.5%, Cr: 0.05 to 0.3%, Sc: 0.05 to 0.3% One or more of (b) mass%, Ag: 0.01 to 0.2%, Sn: 0.001 to 0.1% - 前記アルミニウム合金板のZnの含有量[Zn]とMgの含有量[Mg]とが[Zn]≧-0.5[Mg]+5.75を満足する関係にあり、前記人工時効硬化処理後の0.2%耐力が400MPa以上である、請求項1または2に記載の構造材用アルミニウム合金板。 The Zn content [Zn] and the Mg content [Mg] of the aluminum alloy plate have a relationship satisfying [Zn] ≧ −0.5 [Mg] +5.75, and after the artificial age hardening treatment, The aluminum alloy plate for a structural material according to claim 1 or 2, wherein the 0.2% proof stress is 400 MPa or more.
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EP3239313A3 (en) * | 2016-04-04 | 2019-08-14 | Korea Automotive Technology Institute | Wrought aluminum alloy |
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JP6880989B2 (en) * | 2017-04-26 | 2021-06-02 | 日立金属株式会社 | Adsorption structure unit and their manufacturing method |
CN106929720B (en) * | 2017-05-02 | 2019-03-22 | 常州市亿和合金熔铸有限公司 | A kind of high strength easy recrystallization wrought aluminium alloy and preparation method thereof |
EP3848476A1 (en) * | 2020-01-07 | 2021-07-14 | AMAG rolling GmbH | Sheet or strip made of a curable aluminium alloy, vehicle part manufactured from same, its use and a method for producing the sheet or strip |
KR20230048631A (en) * | 2020-09-17 | 2023-04-11 | 노벨리스 인크. | High Strength and Low Quench Sensitivity 7XXX Series Aluminum Alloys and Manufacturing Methods |
CN113981342B (en) * | 2021-09-03 | 2022-09-06 | 福建祥鑫新材料科技有限公司 | Heat treatment method for improving stress corrosion resistance of 7-series aluminum alloy |
CN115261683B (en) * | 2022-04-04 | 2024-04-09 | 中国第一汽车股份有限公司 | Water quenching-free high-strength and high-toughness cast Al-Si alloy and preparation method thereof |
EP4332260A1 (en) | 2022-09-05 | 2024-03-06 | AMAG rolling GmbH | Age-hardenable aluminium alloy, aluminium alloy metal strip or sheet, method for manufacturing this metal strip or sheet and its use in superplastic forming |
CN115161524B (en) * | 2022-09-08 | 2022-11-29 | 北京科技大学 | Stress corrosion resistant high-strength aluminum alloy and preparation method thereof |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01127642A (en) * | 1987-11-10 | 1989-05-19 | Kobe Steel Ltd | Heat treatment type high strength aluminum alloy plate for drawing and its manufacture |
JP2009221566A (en) * | 2008-03-18 | 2009-10-01 | Kobe Steel Ltd | Aluminum alloy material for high pressure gas vessel having excellent hydrogen embrittlement resistance |
JP2010159489A (en) * | 2008-12-09 | 2010-07-22 | Sumitomo Light Metal Ind Ltd | Method for molding 7,000 series aluminum alloy material, and formed product molded by the same |
WO2014142199A1 (en) * | 2013-03-14 | 2014-09-18 | 株式会社神戸製鋼所 | Aluminum alloy plate for structural material |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2631317A (en) * | 1949-02-18 | 1953-03-17 | Gourielli Inc | Perfume applicator |
US4060411A (en) * | 1975-02-26 | 1977-11-29 | Mamiya Koki Kabushiki Kaisha | Precipitation-hardenable, nitrided aluminum alloys and nitrided mother alloys therefor |
JPH03122247A (en) * | 1989-10-06 | 1991-05-24 | Furukawa Alum Co Ltd | High strength aluminum alloy for welding excellent in stress corrosion cracking resistance |
CN101621006B (en) * | 2008-07-03 | 2011-01-12 | 中芯国际集成电路制造(上海)有限公司 | Method for forming P-type light doping drain electrode region by pre-noncrystallization processing of germanium |
FR2976967B1 (en) * | 2011-06-22 | 2015-05-01 | Total Sa | TRACER FLUIDS WITH MEMORY EFFECT FOR THE STUDY OF A PETROLEUM FACILITY |
CN102876942A (en) * | 2012-09-04 | 2013-01-16 | 昆山市源丰铝业有限公司 | Aluminum alloy plate for vehicle |
-
2014
- 2014-03-17 JP JP2014053702A patent/JP2015175045A/en not_active Ceased
-
2015
- 2015-03-16 WO PCT/JP2015/057774 patent/WO2015141647A1/en active Application Filing
- 2015-03-16 CN CN201580011346.4A patent/CN106062226A/en active Pending
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01127642A (en) * | 1987-11-10 | 1989-05-19 | Kobe Steel Ltd | Heat treatment type high strength aluminum alloy plate for drawing and its manufacture |
JP2009221566A (en) * | 2008-03-18 | 2009-10-01 | Kobe Steel Ltd | Aluminum alloy material for high pressure gas vessel having excellent hydrogen embrittlement resistance |
JP2010159489A (en) * | 2008-12-09 | 2010-07-22 | Sumitomo Light Metal Ind Ltd | Method for molding 7,000 series aluminum alloy material, and formed product molded by the same |
WO2014142199A1 (en) * | 2013-03-14 | 2014-09-18 | 株式会社神戸製鋼所 | Aluminum alloy plate for structural material |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3239313A3 (en) * | 2016-04-04 | 2019-08-14 | Korea Automotive Technology Institute | Wrought aluminum alloy |
EP3680356A1 (en) * | 2016-04-04 | 2020-07-15 | Korea Automotive Technology Institute | Wrought aluminum alloy |
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