WO2017170835A1 - Feuille d'alliage d'aluminium et procédé de fabrication de feuille d'alliage d'aluminium - Google Patents

Feuille d'alliage d'aluminium et procédé de fabrication de feuille d'alliage d'aluminium Download PDF

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WO2017170835A1
WO2017170835A1 PCT/JP2017/013179 JP2017013179W WO2017170835A1 WO 2017170835 A1 WO2017170835 A1 WO 2017170835A1 JP 2017013179 W JP2017013179 W JP 2017013179W WO 2017170835 A1 WO2017170835 A1 WO 2017170835A1
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Prior art keywords
aluminum alloy
temperature
height
treatment
temperature range
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PCT/JP2017/013179
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English (en)
Japanese (ja)
Inventor
久郎 宍戸
智之 北村
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株式会社神戸製鋼所
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Priority claimed from JP2016213789A external-priority patent/JP6306123B2/ja
Application filed by 株式会社神戸製鋼所 filed Critical 株式会社神戸製鋼所
Priority to EP17775369.6A priority Critical patent/EP3438302A4/fr
Priority to CN201780016619.3A priority patent/CN108884524B/zh
Priority to US16/088,679 priority patent/US20190127825A1/en
Publication of WO2017170835A1 publication Critical patent/WO2017170835A1/fr

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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
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • 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
    • 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
    • C22C21/12—Alloys based on aluminium with copper 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
    • C22F1/05—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 of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions
    • 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

Definitions

  • the present invention relates to a 6000 series aluminum alloy plate produced by ordinary rolling and having excellent formability and bake coating curability.
  • panels such as hoods, fenders, doors, roofs, trunk lids, etc., such as outer panels (outer plates) and inner panels (inner plates), are thin and high-strength aluminum alloy plates.
  • Al-Mg-Si based AA to JIS6000 (hereinafter also simply referred to as 6000) aluminum alloy plates are used.
  • This 6000 series (Al-Mg-Si series) aluminum alloy sheet contains Si and Mg as essential components, and especially the excess Si type 6000 series aluminum alloy has excellent age hardening ability during artificial aging treatment. .
  • the moldability is ensured by reducing the yield strength, and even with relatively low-temperature artificial aging treatment such as paint baking treatment of the panel after molding, the yield strength is improved, and as a panel
  • an outer panel of an automobile is manufactured by combining an aluminum alloy plate with a forming process such as an extension forming in a press forming or a bending forming.
  • a forming process such as an extension forming in a press forming or a bending forming.
  • a large outer panel such as a hood or a door is formed into a molded product shape as an outer panel by press molding such as overhanging, and then an inner panel is formed by hem (hemming) processing such as a flat hem at the outer peripheral edge of the outer panel.
  • hem hem
  • the exothermic peak height W1 in the temperature range of 100 to 200 ° C. is 50 ⁇ W or more, and the exotherm in the temperature range of 200 to 300 ° C.
  • the ratio between the peak height W2 and the exothermic peak height W1, W2 / W1 is defined to be 20 or less.
  • the exothermic peak height in the temperature range of 230 to 270 ° C. in the differential scanning calorimetry curve is A
  • the exothermic peak in the temperature range of 280 to 320 ° C is B
  • the exothermic peak height B is not less than 20 ⁇ W / mg
  • the exothermic peak height relative to the exothermic peak height B is The ratios of A and C are respectively defined as A / B of 0.45 or less and C / B of 0.6 or less.
  • a differential scanning calorimetry curve of a 6000 series aluminum alloy plate having a total amount of Mg and Si of 1.2% or less has an exothermic peak within a temperature range of 230 to 330 ° C. There are only two exothermic peaks having a temperature difference between the peaks of 50 ° C. or less, the height of the only one exothermic peak, or the only one of the two exothermic peaks. It defines that the exothermic peak height of the larger peak height is in the range of 20-50 ⁇ W / mg.
  • an endothermic peak in the temperature range of 150 to 230 ° C. as an endothermic peak corresponding to dissolution of Mg—Si clusters in a differential scanning calorimetry curve of a 6000 series aluminum alloy plate that requires Sn addition.
  • the peak height of the exothermic peak in the temperature range of 240 to 255 ° C. is the exothermic peak corresponding to the formation of the Mg—Si cluster, while the peak height of is 8 ⁇ W / mg or less (including 0 ⁇ W / mg). Is 20 ⁇ W / mg or more.
  • Patent Document 5 in a differential scanning calorimetry curve after tempering treatment including solution treatment and quenching treatment of an aluminum alloy material, in a temperature range of 150 to 250 ° C. corresponding to dissolution of Si / vacancy clusters (GPI).
  • the negative endothermic peak height is set to 1000 ⁇ W or less
  • the positive exothermic peak height in the temperature range of 250 to 300 ° C. corresponding to the precipitation of Mg / Si clusters (GPII) is set to 2000 ⁇ W or less
  • room temperature aging suppression and low temperature aging hardening ability are achieved. It is described that it is made excellent.
  • these conventional DSC endothermic peak and exothermic peak control techniques are intended to obtain high BH properties in response to the baking coating curing process for reducing the temperature and time of the automobile parts.
  • the heating temperature is 175 ° C. at the highest, and 150 ° C. in the low example.
  • the BH property in the baking finish hardening process at a high temperature such as 180 ° C. or higher is not intended. Therefore, in such a high temperature baking coating hardening process, it is still an improvement to have a good formability and high BH properties in an Al-Mg-Si aluminum alloy sheet after long-term aging at room temperature. There was room for.
  • the object of the present invention is to provide the conventional low-temperature baking coating curing, as well as good moldability and baking coating curing treatment at the high temperature, even after prolonged aging at room temperature. It is to provide a 6000 series aluminum alloy plate and a method for producing the same that can have high BH properties in processing.
  • the gist of the aluminum alloy plate excellent in formability and bake hardenability of the present invention is, by mass%, Mg: 0.3 to 1.5%, Si: 0.6 to 1 .5%, and the total of Mg content and Si content is more than 1.2%, and the balance is an aluminum alloy plate made of Al and unavoidable impurities.
  • an endothermic peak having a height A of 3 to 10 ⁇ W / mg exists in a temperature range of 150 to 230 ° C., and a height B of 20 to 20 in a temperature range of 230 ° C. or more and less than 330 ° C.
  • An exothermic peak of 50 ⁇ W / mg is present, and the ratio B / A of the maximum peak height B in the exothermic peak to the maximum peak height A in the endothermic peak is more than 3.5; It shall be less than 0.
  • the gist of the method for producing an aluminum alloy plate excellent in formability and bake hardenability of the present invention is mass%, Mg: 0.3 to 1.5%, Si: An aluminum alloy cold-rolled sheet containing 0.6 to 1.5% each, the total of the Mg content and the Si content is more than 1.2%, the balance being Al and inevitable impurities,
  • pre-aging treatment is performed at a temperature range of 30 ° C. to 60 ° C. for 5 hours or more and 500 hours or less.
  • an endothermic peak having a height A of 3 to 10 ⁇ W / mg is present in a temperature range of 150 to 230 ° C.
  • a height B is in a temperature range of 230 ° C. or more and less than 330 ° C.
  • Fever of 20-50 ⁇ W / mg A peak is present, and the ratio B / A between the exothermic peak height B and the endothermic peak height A is more than 3.5 and less than 15.0.
  • the present inventors have good moldability and high BH property even in the conventional low-temperature baking coating curing treatment as well as the high-temperature baking coating curing treatment, even after prolonged room temperature aging.
  • more than a certain number of clusters corresponding to the endothermic peak of the suggested heat curve within the temperature range of 150 to 230 ° C is necessary. did.
  • the baking temperature in the baking coating curing process varies greatly from high temperature to low temperature, in order to obtain a high BH amount at any baking temperature, the number of clusters corresponding to the endothermic peak of the suggested heat curve is reduced.
  • the differential thermal curve for obtaining high BH properties varies depending on the temperature especially in the baking coating curing conditions (artificial aging treatment conditions), and at a relatively low baking coating temperature of 175 ° C. or lower, 180 ° C. or higher. It was also found that it is necessary to control the differential heat curve more precisely than the relatively high baking coating temperature.
  • the present invention performs structure control to control the differential heat curve more precisely, and it can be said that the 6000 series aluminum alloy plates as materials for automobile members are mutually contradictory. Both have low-temperature BH properties.
  • the aluminum alloy plate (molding material plate) referred to in the present invention is a rolled plate such as a hot rolled plate or a cold rolled plate, and is subjected to tempering (T4) such as solution treatment and quenching treatment. It is a raw material aluminum alloy plate before being formed into an automobile member to be used and before being subjected to artificial aging treatment (artificial age hardening treatment) such as paint baking hardening treatment.
  • T4 tempering
  • It is a raw material aluminum alloy plate before being formed into an automobile member to be used and before being subjected to artificial aging treatment (artificial age hardening treatment) such as paint baking hardening treatment.
  • artificial age hardening treatment artificial age hardening treatment
  • paint baking hardening treatment paint baking hardening treatment.
  • aluminum is also referred to as aluminum or Al.
  • 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 component composition of the aluminum alloy plate of the present invention is determined so as to satisfy the required formability and bake hardenability from the composition of the 6000 series aluminum alloy as a material of an automobile member such as the automobile large body panel.
  • the chemical composition of the aluminum alloy sheet of the present invention includes, in mass%, Mg: 0.3 to 1.5% and Si: 0.6 to 1.5%, respectively, and the Mg content. And the Si content are over 1.2%, and the balance consists of Al and inevitable impurities.
  • Cu 0.02 to 0.8%
  • Fe 0.05 to 0.5%
  • Mn 0.05 to 0.3%
  • Zr 0.04 to 0.1%
  • V 0.02 to 0.1%
  • Ag 0.01 to 0.1%
  • Zn 0.01 to 0.3% The above may be included.
  • Si 0.6 to 1.5% Si, together with Mg, forms aging precipitates such as Mg-Si-based precipitates that contribute to strength improvement during solid solution strengthening and artificial aging treatment such as baking coating treatment, and exhibits age-hardening ability. It is an essential element for obtaining strength (yield strength). If the Si content is too small, the amount of solute Si before baking coating treatment (before artificial aging heat treatment) will decrease, and the amount of Mg-Si-based precipitates will be insufficient, resulting in a marked decrease in BH properties and strength. Run short.
  • the Si content is in the range of 0.6 to 1.5%, preferably in the range of 0.7 to 1.5%.
  • Mg 0.3-1.5% Mg and Si, together with solid solution strengthening, form aging precipitates such as Mg-Si-based precipitates that contribute to strength improvement during artificial aging heat treatment such as baking coating treatment, and show age-hardening ability. It is an essential element for obtaining strength. If the Mg content is too small, the amount of solid solution Mg before baking coating treatment is reduced, and the amount of Mg—Si based precipitates is insufficient, so that the BH property is remarkably lowered and the strength is insufficient. On the other hand, when there is too much Mg content, it will become easy to form a shear band at the time of cold rolling, and will cause the crack at the time of a raw material plate rolling. Therefore, the Mg content is in the range of 0.3 to 1.5%, preferably in the range of 0.4 to 0.8%.
  • the total of the Mg content and the Si content is over 1.2%.
  • the total is 1.2% or less as in Patent Document 3, even if the production conditions of the board are within a preferable range described later, an endothermic peak or an exothermic peak defined in the present invention cannot be generated, Artificial age-hardening ability is insufficient, and the required strength cannot be obtained.
  • the upper limit of the total of the Mg content and the Si content is determined by the limit at which the plate can be produced without causing hot rolling cracking, and is preferably 2.5%.
  • Cu can improve strength by solid solution strengthening. If the Cu content is too small, the effect is small, and if it is too much, the effect is saturated, and on the contrary, the corrosion resistance is deteriorated.
  • Fe forms a crystallized product, serves as a nucleus of recrystallized grains, prevents coarsening of crystal grains, and plays a role of improving strength. If the content is too small, the effect is small. If the content is too large, a coarse compound is formed, which becomes a starting point of destruction, and the strength and formability are lowered.
  • Mn, Zr, Cr, V contributes to strength improvement by refining the crystal grains of the ingot and final plate product. Further, these elements exist as dispersed particles, contribute to crystal grain refinement, and improve moldability. When each content is too small, the effect of improving strength and formability due to the refinement of crystal grains is insufficient. On the other hand, when there are too many of these elements, a coarse compound will be formed and ductility will deteriorate.
  • Ag has the effect of closely and finely precipitating aging precipitates that contribute to strength improvement by artificial aging heat treatment after molding of automobile parts, thereby promoting high strength. If the content is too small, the effect of improving the strength is small, and if the content is too large, various properties such as rollability and weldability are reduced, and the effect of improving the strength is saturated and expensive.
  • Zn is useful for improving artificial age-hardening ability (BH property), and has an effect of increasing the strength by promoting precipitation of a compound phase such as a GP zone in the crystal grains of the plate structure in the baking coating process. .
  • Ti and B are inevitable impurities. Ti, together with B, forms a coarse compound and degrades mechanical properties. However, since the inclusion of a small amount also has the effect of refining the crystal grains of the aluminum alloy ingot, each content in the range specified by the JIS standard is allowed as a 6000 series alloy. As an example of this allowable amount, Ti is 0.1% or less, preferably 0.05% or less. Further, B is set to 0.03% or less. Incidentally, in the present invention, Sn, which is essential in Patent Document 4, is not added.
  • the Mg-Si clusters are reduced on the contrary when the preferable production conditions for the plate are described later, the endothermic peak and the exothermic peak defined in the present invention cannot be generated, and the artificial age hardening ability is insufficient. As a result, the required strength may not be obtained.
  • the structure of an aluminum alloy plate is used as an index indicating in advance the state of artificial aging precipitates in a member made of this plate, and DSC obtained by differential scanning calorimetry ( Differential scanning calorimetry curve: DSC profile).
  • DSC differential scanning calorimetry curve: DSC profile
  • the present invention is capable of baking at a relatively low temperature as well as good formability and high BH property in a relatively high temperature baking coating curing process, which is the main target, even after prolonged room temperature aging.
  • DSC differential scanning thermal analysis curve: DSC profile
  • the clusters corresponding to the endothermic peaks are dissolved in an extremely short time, and then a strengthening phase is easily generated. It is presumed that even if a peak is present in advance, a high BH property can be obtained. For this reason, the endothermic peak can be increased under the relatively high temperature baking finish curing conditions targeted by the present invention, and the work curability can be enhanced by the presence of clusters corresponding to the endothermic peak. Therefore, if there is also an exothermic peak in the temperature range of 230 ° C. or higher and lower than 330 ° C. that enhances BH properties, both high work curability (formability) and BH properties can be achieved.
  • This relatively high temperature baking coating curing treatment condition means, for example, that the baking coating curing treatment is performed under the conditions of a heating temperature of 180 to 230 ° C. and a heating holding time of 10 to 30 minutes.
  • the heating temperature of the baking coating curing process is distinguished from at most 175 ° C. in particular at the heating temperature.
  • the balance between the peak heights as well as the respective peak heights is important. For example, when the ratio of the exothermic peak / endothermic peak is too small, the existence of clusters corresponding to the endothermic peak is too large and the BH property is too low, or the exothermic peak is too low and there are too many clusters that become the reinforcing phase. , Elongation will decrease. On the other hand, if the exothermic peak / endothermic peak is too large, the presence of clusters corresponding to the endothermic peak is too small and the work hardenability is inferior, or the exothermic peak is too high and there are too few clusters that become the reinforcing phase. Is too low.
  • the DSC before artificial aging treatment of the aluminum alloy sheet is within a temperature range of 150 to 230 ° C.
  • An endothermic peak having a height A of 3 to 10 ⁇ W / mg is present, and an exothermic peak having a height B of 20 to 50 ⁇ W / mg is present in a temperature range of 230 ° C. or higher and lower than 330 ° C., and
  • the ratio B / A between the exothermic peak height B and the endothermic peak height A is more than 3.5 and less than 15.0.
  • a peak is present, and the ratio B / A between the exothermic peak height B and the endothermic peak height A is more than 3.5 and less than 15.0. More preferably, the endothermic peak height A is 3 to 7 ⁇ W / mg, and the exothermic peak height B is 20 to 35 ⁇ W / mg.
  • the fact that the endothermic peak is high on the minus side means that the cluster is dissolved during the differential thermal analysis, in other words, there are many clusters corresponding to the endothermic peak.
  • the negative peak height A is as low as less than 3 ⁇ W / mg, the work curability is lowered and the moldability is lowered.
  • the negative peak height A is too high exceeding 10 ⁇ W / mg, the relatively high-temperature BH property decreases, and if it exceeds 7 ⁇ W / mg, the relatively low-temperature BH is decreased. The nature will decline.
  • a high exothermic peak means that many clusters that are the core of the reinforcing phase or the reinforcing phase are generated during the differential thermal analysis, in other words, the strengthening phase or the strengthening phase. This means that there are few core clusters. If the positive peak height B exceeds 50 ⁇ W / mg, the reinforcing phase or the core of the reinforcing phase is too few, and the BH property of baking coating curing at a relatively high temperature becomes low, resulting in 40 ⁇ W. If it exceeds / mg and is too high, the BH property of baking coating curing at a relatively low temperature will be low.
  • the structure defined by DSC at the stage of the material plate is very much affected by the generation behavior of the precipitated phase during the artificial aging treatment (at the time of BH) of the member such as the automobile panel manufactured from the material plate. There is a good correlation. As a result, it is possible to evaluate the formability and BH property of the material plate by controlling the DSC at the stage of the material plate without bothering manufacturing the member.
  • the structure defined by the DSC at the stage of the material plate can be an index of formability and BH property in a member using the material plate as a molding material.
  • Patent Document 1 there is no endothermic peak having a height of 3 to 10 ⁇ W / mg in the temperature range of 150 to 230 ° C., and conversely, an exothermic peak is present in the temperature range of 100 to 200 ° C.
  • Patent Document 2 as shown in FIG. 1, there is no endothermic peak having a height of 3 to 10 ⁇ W / mg within a temperature range of 150 to 230 ° C.
  • Patent Document 3 the total amount of Mg and Si is 1.2% or less, the endothermic peak and the exothermic peak defined in the present invention cannot be generated, the artificial age hardening ability is insufficient, and the necessary strength is obtained. It becomes impossible.
  • Patent Document 4 as shown in FIG.
  • the conventional DSC endothermic peak and exothermic peak control technique is different from the DSC endothermic peak and exothermic peak defined in the present invention.
  • the high elongation (formability) and bake coating curability of the 6000 series aluminum alloy plate after long-term aging at room temperature cannot be achieved.
  • Control of the structure specified by the DSC exothermic peak is performed as follows.
  • the aluminum alloy cold-rolled sheet is heated within a temperature range of 30 ° C. to 60 ° C. for 5 hours or more, 500 hours or less within 1 hour after solution treatment and quenching treatment.
  • Preliminary aging treatment at a low temperature for a long time is performed. Further, in order to increase the BH property at a relatively low temperature, as will be described later, it is maintained within a temperature range of 100 ° C. to 300 ° C. for 5 seconds or more and 300 seconds or less within 1 hour after the solution treatment and quenching treatment.
  • the preliminary aging treatment is performed. For this reason, there is an advantage that it can be controlled without greatly changing the composition of the 6000 series aluminum alloy already standardized as the automobile member of the rolled plate and without greatly changing the rolling process by a conventional method.
  • the 6000 series aluminum alloy sheet of the present invention is a cold-rolled sheet obtained by subjecting an ingot to hot rolling after soaking and then cold rolling, and further subjected to tempering such as solution treatment. Manufactured. That is, an aluminum alloy hot rolled sheet having a thickness of about 2 to 10 mm is manufactured through normal manufacturing processes such as casting, homogenization heat treatment, and hot rolling. Subsequently, it is cold-rolled to obtain a cold-rolled sheet having a thickness of 3 mm or less.
  • an ordinary molten casting method such as a continuous casting method and a semi-continuous casting method (DC casting method) is appropriately selected for the molten aluminum alloy adjusted to be dissolved within the above-mentioned 6000 series component composition range.
  • the average cooling rate at the time of casting is as large as possible (fast) from the liquidus temperature to the solidus temperature of 30 ° C./min. Is preferred.
  • the cooling rate in this high temperature region is inevitably slow.
  • the cast aluminum alloy ingot is subjected to a homogenization heat treatment prior to hot rolling.
  • This homogenization heat treatment (uniform heat treatment) is important for sufficiently dissolving Si and Mg in addition to the normal purpose of homogenizing the structure (eliminating segregation in crystal grains in the ingot structure). It is.
  • the homogenization heat treatment temperature is 500 ° C. or more and 580 ° C. or less, and the homogenization (retention) time is appropriately selected from a range of 1 hour or more to sufficiently dissolve Si and Mg. If the homogenization temperature is low, the solid solution amount of Si and Mg cannot be secured, and the DSC exothermic peak can be defined by the pre-aging treatment (reheating treatment) after the solution treatment and quenching treatment described later. Disappear. Further, segregation in the crystal grains cannot be sufficiently eliminated, and this acts as a starting point of fracture, so that formability is lowered.
  • the temperature of the ingot is not lowered to 450 ° C. or lower without lowering the temperature of the ingot. It is preferable to ensure the amount of solution.
  • Si and Mg are likely to precipitate, and there is a high possibility that the solid solution amount of Si and Mg cannot be secured for the purpose of the DSC. Become.
  • Hot rolling is composed of a rough rolling process of an ingot (slab) and a finish rolling process according to the thickness of the sheet to be rolled.
  • a reverse or tandem rolling mill is appropriately used.
  • hot finish rolling with an end temperature in the range of 250 to 360 ° C. is performed. If the soaking temperature or the finishing temperature of this finish rolling is too low, Mg and Si compounds are generated during soaking and hot rolling, and the balance of solid solution Mg / Si changes, It becomes difficult to make the DSC regulation.
  • Hot rolled sheet annealing Annealing of the hot-rolled sheet before cold rolling is not necessary, but may be performed.
  • Cold rolling In the cold rolling, the hot-rolled sheet is rolled to produce a cold-rolled sheet (including a coil) having a desired final thickness.
  • the cold rolling rate is desirably 60% or more, and intermediate annealing may be performed between cold rolling passes for the same purpose as the annealing.
  • the average cooling rate from the solution temperature to the quenching stop temperature at room temperature is desirably 20 ° C./s or more. If the average cooling rate of the quenching treatment to room temperature after the solution treatment is small, coarse Mg 2 Si and simple substance Si are generated during cooling, and bending workability is deteriorated. Moreover, the amount of solid solution after solution forming falls, and BH property will fall. In order to ensure this cooling rate, the quenching treatment is performed by selecting water cooling means and conditions such as air cooling such as a fan, mist, spray, and immersion, respectively.
  • Preliminary aging treatment reheating treatment
  • reheating treatment After such a solution treatment, it is preferable to quench the steel sheet and cool it to room temperature, and then subject the cold-rolled sheet to a pre-aging treatment (reheating treatment) within one hour.
  • This preliminary aging treatment is held at a temperature range of 30 ° C. to 60 ° C. for 5 hours or more and 500 hours or less as a lower temperature and longer time than the conventional method for the control of the structure specified by the DSC peak.
  • Mg—Si clusters with a good balance between Mg and Si are formed, and the structure specified by the DSC peak is obtained. Therefore, the high aging and the BH property at a relatively high temperature can be combined by the low-temperature long-time preliminary aging treatment.
  • the solution treatment and quenching treatment and the reheating treatment may be continued so that there is almost no time difference, and the lower limit time is not particularly set.
  • the preliminary aging temperature is less than 30 ° C. or the holding time is less than 5 hours, as in the case where this preliminary aging treatment is not performed, too many clusters corresponding to endothermic peaks are generated, BH property tends to be low.
  • the pre-aging condition exceeds 60 ° C. or exceeds 500 hours, the amount of clusters that form the core of the strengthening phase and the strengthening phase corresponding to the exothermic peak is too much, and the press before baking coating. The strength at the time of molding becomes too high, and the moldability tends to deteriorate.
  • the temperature is maintained at a temperature range of 100 ° C. to 300 ° C. for 5 seconds or more and 300 seconds or less. It is preferable to perform the preliminary aging treatment for a long time at a low temperature and immediately after the preliminary aging treatment for a short time at a high temperature.
  • the DSC can be reliably controlled by the low-temperature long-time pre-aging treatment, and the endothermic peak height A in the temperature range of 150 to 230 ° C. in the DSC is more preferably in the range of 3 to 8 ⁇ W / mg. The preferred range is 3 to 7 ⁇ W / mg.
  • the height B of the exothermic peak in the temperature range of 230 ° C. or higher and lower than 330 ° C. in DSC can be controlled to be a preferable range of 20 to 40 ⁇ W / mg, and a more preferable range of 20 to 35 ⁇ W / mg. If this high temperature and short time pre-aging treatment is not performed or if the above conditions are not met, the structure specified by the DSC peak may not be obtained or the structure may be relatively low. There is a possibility that the BH property of the resin becomes low.
  • the aluminum alloy plate of the present invention manufactured with the structure specified by the DSC peak is press-molded as a material on a large body panel or the like of an automobile and then baked after being painted.
  • the coating is hardened (artificial aging treatment) to increase the strength.
  • the baking coating curing treatment is preferably performed at a higher temperature in order to achieve the effects of the present invention, and examples include conditions of a heating temperature of 180 to 230 ° C. and a heating and holding time of 10 to 30 minutes. If the heating temperature is too low, for example, if the heating temperature is too low, the structure indicated by the differential heat curve needs to be more precisely controlled as described above.
  • 6000 series aluminum alloy plates having different structures defined by the DSC of the present invention were produced by making different compositions and production conditions. And after Assembling the board, after holding at room temperature for 100 days, As proof strength (proof strength before baking coating hardening treatment), AB proof strength (proof strength after baking coating hardening treatment), elongation at break, BH property (paint bake hardening property), respectively Measurement and evaluation. These results are shown in Tables 1 and 2.
  • the above-described method of making the samples was carried out by changing the pre-aging treatment conditions of the 6000 series aluminum alloy plate having the composition shown in Table 1 after solution treatment and quenching treatment as shown in Table 2.
  • the display of the content of each element in Table 1 the display in which the numerical value of each element is blank indicates that the content is below the detection limit.
  • the specific production conditions of the aluminum alloy plate were the same (same) as follows in each example except for the preliminary aging treatment conditions.
  • Aluminum alloy ingots having respective compositions shown in Table 1 were commonly melted by DC casting.
  • the average cooling rate during casting was set to 50 ° C./min from the liquidus temperature to the solidus temperature.
  • the ingot after chamfering as necessary is subjected to a soaking treatment at 550 ° C. for 10 hours, and then hot rough rolling is started at that temperature, and then the end temperature is set to 250 to 360 ° C.
  • a hot finish rolling was performed to obtain a hot rolled sheet.
  • This hot-rolled sheet was cold-rolled at a processing rate of 67% to obtain a cold-rolled sheet having a thickness of 1.0 mm.
  • each cold-rolled plate was subjected to a solution treatment for 1 minute at 550 ° C. using a glass furnace, and then cooled to room temperature by water cooling. Within 1 hour after this cooling, high temperature short time pre-aging using an oil bath and low temperature long time pre-aging using an atmospheric furnace are performed at the temperature (° C) and holding time (hr) shown in Table 2. After the preliminary aging treatment, air cooling was performed.
  • test plate 300 mm ⁇ 300 mm was cut out from the longitudinal end portion and the width center portion of the product, and the DSC of each test plate was cut. And properties were measured and evaluated. These results are shown in Table 2.
  • test equipment TG / DTA6300 manufactured by Seiko Instruments
  • standard material aluminum
  • sample container aluminum
  • temperature rise condition 10 ° C./min
  • atmosphere argon (50 ml / min)
  • sample weight 39.0 to 41.0 mg
  • the obtained differential thermal analysis profile ( ⁇ W) was divided by the sample weight ( ⁇ W / mg), and then the differential heat In the section of 0 to 100 ° C. in the analysis profile, the region where the profile of differential thermal analysis was horizontal was taken as a reference level of 0, and the endothermic peak height and exothermic peak height from this reference level were measured.
  • Paint bake hardenability As mechanical properties of the test plate, 0.2% yield strength (As yield strength) and elongation at break (%) were determined by a tensile test. In addition, each of these test plates is commonly used, and after 2% stretching simulating press molding on the automobile member, the coating baking and curing treatment at high temperature is 185 ° C. ⁇ 20 minutes, and the coating is performed at low temperature. The 0.2% yield strength (AB yield) of the test plate after each artificial age hardening treatment (after BH) of 170 ° C. ⁇ 20 minutes as the bake hardening treatment was determined by a tensile test.
  • AB yield 0.2% yield strength
  • the 0.2% proof stress after BH which evaluated the BH property of each test plate from the difference (increased proof stress) between these 0.2% proof stresses is the baking baking hardening process (185 degreeC * 20 at high temperature). 190) or more at a low temperature, and at least 170 MPa or more, preferably at 180 MPa or more, at a low temperature in a paint bake hardening process at a low temperature (170 ° C. ⁇ 20 minutes). It was. Note that the elongation at break, which is the evaluation of press formability, is only 1% difference between 24% and 25%. For example, corners and character lines with sharpened or complicated outer panel shapes of automobiles are distorted. It has a great influence on whether or not it can be molded with a beautiful and sharp curved surface structure without wrinkles.
  • No. 13A test piece (20 mm ⁇ 80 mmGL ⁇ plate thickness) of JISZ2201 was sampled from each test plate, and a tensile test was performed at room temperature.
  • the tensile direction of the test piece at this time was the direction perpendicular to the rolling direction.
  • the tensile speed was 5 mm / min up to 0.2% proof stress and 20 mm / min after proof stress.
  • the N number for the measurement of mechanical properties was 5, and each was calculated as an average value.
  • the test piece for measuring the yield strength after BH was subjected to the BH treatment after giving a pre-strain of 2% to the test piece by the tensile tester.
  • Invention Examples 1 to 8 are produced in the component composition range of the present invention and in a preferable condition range, and subjected to a pre-aging treatment at a low temperature for a long time in the preferable range. Therefore, as shown in Table 2, these invention examples are as defined by DSC in the present invention. Even after long-term room temperature aging, as shown in Table 2, the moldability and BH properties are excellent. ing. Specifically, it has a high elongation at break of at least 26%, a BH property of at least 192 MPa or higher (185 ° C. ⁇ 20 minutes), and a BH property of at least 162 MPa or more (170 ° C. ⁇ 20 minutes). have.
  • the inventive example 2 which was immediately subjected to the low temperature and the long time preliminary aging treatment was subjected to the preliminary aging treatment at a high temperature and a short time.
  • the BH property at a relatively low temperature is higher than that of Invention Example 1 in which only the preliminary aging treatment at a low temperature and a long time was performed without applying.
  • the invention examples 6, 7, and 8 that were subjected to the pre-aging treatment for a short time at a high temperature and immediately subjected to the pre-aging treatment for a long time at a low temperature were not subjected to the pre-aging treatment for a short time at a high temperature.
  • the BH property at a relatively low temperature is high on average although it depends on the difference in the alloy composition.
  • the invention examples 2, 6, 7, and 8 further added a pre-aging treatment at high temperature and short time, so that the endothermic peak height A in the temperature range of 150 to 230 ° C. in DSC is within a preferable range (3 ⁇ 8 ⁇ W / mg), more preferable range (3 to 7 ⁇ W / mg), and the exothermic peak height B in the temperature range of 230 ° C. or higher and lower than 330 ° C. in DSC is also preferable range (20 to 40 ⁇ W / mg) In addition, it is because it can be controlled more precisely within a more preferable range (20 to 35 ⁇ W / mg).
  • Comparative Examples 1 to 6 in Table 2 use the same alloy example 1 as the invention example.
  • the production conditions such as the temperature of the preliminary aging treatment and the holding time are out of the preferable conditions.
  • DSC deviates from the range defined in the present invention, and either BH property or formability after long-term aging at room temperature is inferior to that of Invention Example 1 having the same alloy composition, and can be combined.
  • the elongation at break is 26% or more, the BH property at a high temperature (185 ° C. ⁇ 20 minutes) is less than 190 MPa, or the BH property at a high temperature (185 ° C. ⁇ 20 minutes) is 190 MPa or more.
  • the elongation at break is less than 25%, which does not satisfy the above acceptance criteria.
  • Comparative Example 1 is not subjected to preliminary aging treatment. Therefore, although an endothermic peak exists in the temperature range of 150 to 230 ° C., the height A is too high exceeding 10 ⁇ W / mg, and the exothermic peak height B in the temperature range of 230 ° C. or higher and lower than 330 ° C. Is too high, exceeding 50 ⁇ W / mg. In Comparative Example 2, the time for the preliminary aging treatment on the low temperature side is too short. Therefore, although an endothermic peak exists in the temperature range of 150 to 230 ° C., the height A is too high exceeding 10 ⁇ W / mg, and the exothermic peak height B in the temperature range of 230 ° C. or higher and lower than 330 ° C.
  • Comparative Examples 7 and 8 in Table 2 are manufactured in a preferable range including the pre-aging conditions, Alloy Nos. 7 and 8 in Table 1 are used, respectively, and the alloy compositions are out of the scope of the present invention. ing. For this reason, as shown in Table 2, these comparative examples, as a result, DSC and the like are out of the range defined in the present invention. Either is inferior and cannot be combined. Specifically, even when the elongation at break is 25% or more, the BH property at a high temperature (185 ° C. ⁇ 20 minutes) is about 138 to 146 MPa, and the BH property at a low temperature (170 ° C. ⁇ 20 minutes) is 133- Only about 139 MPa.
  • the comparative example 7 is the alloy 7 of Table 1, and there is too little Mg and the quantity of the total content of Mg and Si is also too small. For this reason, although an endothermic peak exists in the temperature range of 150 to 230 ° C., the height A is too low as less than 3 ⁇ W / mg, and the exothermic peak height B in the temperature range of 230 ° C. or higher and lower than 330 ° C. is also It is too low, less than 20 ⁇ W / mg.
  • the comparative example 8 is the alloy 8 of Table 1, Si is too little, and the total content of Mg and Si is too little.
  • the height A is too low as less than 3 ⁇ W / mg
  • the exothermic peak height B in the temperature range of 230 ° C. or higher and lower than 330 ° C. is also It is too low, less than 20 ⁇ W / mg.
  • FIG. 1 The DSC selected from these invention examples and comparative examples is shown in FIG.
  • the unit of the vertical axis indicated as “Heat Flow” is ⁇ W / m
  • the thick solid line indicates Invention Example 1 in Table 2
  • the thick dotted line (broken line) indicates Invention Example 2
  • the thin dotted line indicates Comparative Example 3.
  • an endothermic peak having a height A of 3 to 10 ⁇ W / mg exists in a temperature range of 150 to 230 ° C.
  • an exothermic peak having a height B of 20 to 50 ⁇ W / mg Is present in a temperature range of 230 ° C. or more and less than 260 ° C., and in the temperature range of 260 ° C. or more and less than 330 ° C., no exothermic peak having a height of 20 ⁇ W / mg or more is present.
  • composition and DSC specified in the present invention are required to combine good moldability and high BH properties even after baking at room temperature for a long time or at a high temperature by baking.
  • the critical significance of each of these conditions is supported.
  • a 6000 series aluminum alloy plate that has both good formability and high BH properties even after baking at room temperature for a long time or at a high temperature by baking. That is, even after long-time aging at room temperature, it is possible to have both good moldability and high BH properties in the conventional low-temperature baking coating curing treatment as well as the conventional high-temperature baking coating curing treatment.
  • the application of a 6000 series aluminum alloy plate can be expanded as an automobile member including a panel material.

Abstract

La présente invention a trait à une feuille d'alliage d'aluminium et à un procédé de fabrication de feuille d'alliage d'aluminium. Sur une courbe calorimétrique d'analyse thermique différentielle d'une feuille d'alliage d'aluminium Al-Mg-Si possédant une composition spécifique dans laquelle la teneur totale en Mg et Si est supérieure à 1,2 %, le rapport (B/A) d'un pic endothermique dans la plage de température de 150 à 230 °C possédant une hauteur A de 3 à 10 µW/mg et d'un pic exothermique dans la plage de température de 230 °C à moins de 330 °C possédant une hauteur B de 20 à 50 µm se situe dans une fourchette spécifiée.
PCT/JP2017/013179 2016-03-30 2017-03-30 Feuille d'alliage d'aluminium et procédé de fabrication de feuille d'alliage d'aluminium WO2017170835A1 (fr)

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EP17775369.6A EP3438302A4 (fr) 2016-03-30 2017-03-30 Feuille d'alliage d'aluminium et procédé de fabrication de feuille d'alliage d'aluminium
CN201780016619.3A CN108884524B (zh) 2016-03-30 2017-03-30 铝合金板和铝合金板的制造方法
US16/088,679 US20190127825A1 (en) 2016-03-30 2017-03-30 Aluminum alloy sheet and aluminum alloy sheet manufacturing method

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CN111247260A (zh) * 2017-10-23 2020-06-05 诺维尔里斯公司 高强度高度可成型的铝合金及其制作方法
CN112410628A (zh) * 2020-12-03 2021-02-26 河南永通铝业有限公司 一种幕墙用高强度铝合金板材及其制备方法

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JP2011017063A (ja) * 2009-07-10 2011-01-27 Furukawa-Sky Aluminum Corp 冷間プレス成形用アルミニウム合金板ブランクの製造方法、およびそれによる冷間プレス成形方法および成形品
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JP2003105471A (ja) * 2001-09-28 2003-04-09 Sumitomo Light Metal Ind Ltd アルミニウム合金板およびその製造方法
JP2011017063A (ja) * 2009-07-10 2011-01-27 Furukawa-Sky Aluminum Corp 冷間プレス成形用アルミニウム合金板ブランクの製造方法、およびそれによる冷間プレス成形方法および成形品
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111247260A (zh) * 2017-10-23 2020-06-05 诺维尔里斯公司 高强度高度可成型的铝合金及其制作方法
CN112410628A (zh) * 2020-12-03 2021-02-26 河南永通铝业有限公司 一种幕墙用高强度铝合金板材及其制备方法

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