JP2017179456A - Al-Mg-Si-BASED ALLOY MATERIAL - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-Mg-Si-based alloy material having high strength while having high conductivity and good processability.SOLUTION: An Al-Mg-Si-based alloy material having a fiber structure has a tensile strength of 170 MPa or more, a value of 0.2% bearing force divided by the tensile strength (MPa) of 0.91 to 1.00 and conductivity of 54%IACS or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an Al—Mg—Si based alloy material, and more particularly to an Al—Mg—Si based alloy material excellent in thermal conductivity, conductivity, strength and workability.

  Heating elements such as flat panel TVs, thin monitors for personal computers, laptop computers, tablet computers, car navigation systems, portable navigation systems, chassis of products such as mobile terminals such as smartphones and mobile phones, metal base printed boards, and internal covers In a member material to be built in or mounted, excellent thermal conductivity, strength, and workability for quickly radiating heat are required.

  Pure aluminum alloys such as JIS 1100, 1050, and 1070 have excellent thermal conductivity but low strength. An Al—Mg alloy (5000-based alloy) such as JIS 5052 used as a high strength material is significantly inferior in thermal conductivity and conductivity to a pure aluminum-based alloy.

  In contrast, Al—Mg—Si based alloys (6000 based alloys) have good thermal conductivity and electrical conductivity, and can be improved in strength by age hardening. A method for obtaining an aluminum alloy plate excellent in conductivity and workability has been studied.

  For example, Patent Document 1 contains 0.1 to 0.34% by mass of Mg, 0.2 to 0.8% by mass of Si, 0.22 to 1.0% by mass of Cu, and the balance is Al and An alloy consisting of unavoidable impurities and having a Si / Mg content ratio of 1.3 or more is made into an ingot having a thickness of 250 mm or more by semi-continuous casting, hot-rolled through preheating at a temperature of 400 to 540 ° C., 50 A method for producing a rolled sheet is disclosed, which is characterized by annealing at a temperature of 140 to 280 ° C. after cold rolling at a reduction rate of ˜85%.

  Patent Document 2 contains Si: 0.2 to 1.5 mass%, Mg: 0.2 to 1.5 mass%, Fe: 0.3 mass% or less, and Mn: 0.02 to 0.15% by mass, Cr: 0.02 to 0.15% of 1 type or 2 types, and the balance of Al and Ti in unavoidable impurities is restricted to 0.2% or less, or An aluminum alloy plate having a composition containing one or two of Cu: 0.01 to 1% by mass or rare earth element: 0.01 to 0.2% by mass is produced by continuous casting and then cold rolled. Then, a solution treatment at 500 to 570 ° C. is performed, followed by further cold rolling at a cold rolling rate of 5 to 40%, and an aging treatment for heating to 150 to 190 ° C. after the cold rolling. Made of aluminum alloy plate with excellent thermal conductivity, strength and bending workability The method has been described.

  Patent Document 3 discloses a heat radiating member manufactured by homogenizing an Al—Mg—Si alloy ingot, processing a hot rough rolling and a hot finish rolling, and then processing a cold rolled alloy plate into a required shape. Si: 0.2-0.8 wt%, Mg: 0.3-0.9 wt%, Fe: 0.35 wt% or less, Cu: 0.20 wt% or less, the balance Al and inevitable impurities An aluminum heat dissipating member characterized by comprising:

  In the Al-Mg-Si based alloy, the thermal conductivity and electrical conductivity have a good correlation, and the aluminum alloy plate having excellent thermal conductivity has excellent electrical conductivity, not to mention the heat dissipation member material It can be used as a conductive member material.

JP 2012-62517 A JP 2007-9262 A JP 2003-226628 A

  Workability is affected by the relationship between tensile strength and yield strength. When the proof stress is lower than the tensile strength, work hardening occurs, and in the case of multi-stage forming, workability decreases. In addition, the workability changes depending on the metal structure of the Al—Mg—Si based alloy plate.

  However, in patent document 1, examination of process conditions is inadequate and proof stress is not examined. In Patent Document 1, the tensile strength is improved by the contribution of Si or Cu, and the element next to Al is Si or Cu, the content of Mg is relatively small, and Si and Mg Are not included in the claims of Patent Document 1.

  In patent document 2, although the comparatively high intensity | strength is obtained, the electroconductivity as described in an Example is low.

  In Patent Document 3, Invention 1 has a small difference in tensile strength and yield strength but has low thermal conductivity. In Invention 2, although the thermal conductivity is higher than that in Invention 1, the difference in tensile strength and yield strength is larger than that of Invention 1.

  Patent Document 2 and Patent Document 3 do not describe the metal structure of the obtained Al—Mg—Si based alloy plate.

  As described above, it is very difficult to obtain an Al—Mg—Si alloy plate having high electrical conductivity that is close to the values of tensile strength and proof stress.

  In view of the technical background described above, the present invention has a high value obtained by dividing 0.2% proof stress (MPa) by tensile strength (MPa), and has high conductivity, good workability, and high strength. It aims at providing Si system alloy material.

The above problem is solved by the following means.
(1) Tensile strength is 170 MPa or more, 0.2% proof stress (MPa) divided by tensile strength (MPa) is 0.91 or more and 1.00 or less, and conductivity is 54% IACS or more. An Al—Mg—Si alloy material having a fiber structure.
(2) Chemical composition contains Si: 0.2-0.8 mass%, Mg: 0.3-1 mass%, Fe: 0.5 mass% or less, and Cu: 0.5 mass% or less, 2. The Al—Mg—Si based alloy material according to item 1 above, comprising the balance Al and inevitable impurities.
(3) The Al—Mg—Si-based alloy material according to item 2, wherein Mn, Cr, Zn, and Ti as impurities are each regulated to 0.1 mass% or less.
(4) The Al—Mg—Si alloy material according to any one of items 1 to 3, wherein the tensile strength is 200 MPa or more.
(5) The Al—Mg—Si alloy material according to any one of items 1 to 3, wherein the tensile strength is 220 MPa or more.
(6) The Al—Mg—Si alloy material according to any one of items 1 to 3, wherein the tensile strength is 250 MPa or more.

  According to the invention described in item (1), the tensile strength is high, the value obtained by dividing the 0.2% proof stress (MPa) by the tensile strength (MPa) is large, and Al- having a fiber structure with high electrical conductivity. It can be formed as an Mg-Si alloy material.

  According to the invention described in the preceding item (2), the chemical composition is Si: 0.2 to 0.8 mass%, Mg: 0.3 to 1 mass%, Fe: 0.5 mass% or less, and Cu: 0 .5% by mass or less, and the balance is Al and inevitable impurities, so the tensile strength is high, the value obtained by dividing the 0.2% proof stress (MPa) by the tensile strength (MPa) is large, and the conductivity is high. An Al—Mg—Si alloy material having a fiber structure can be obtained.

  According to the invention described in the preceding item (3), since Mn, Cr, Zn, and Ti are respectively regulated to 0.1% by mass or less, the tensile strength is high and the 0.2% proof stress (MPa). Can be obtained as an Al—Mg—Si based alloy material having a fiber structure having a large electrical conductivity and a value obtained by dividing by a tensile strength (MPa).

  According to the invention described in the preceding item (4), it can be formed as an Al—Mg—Si alloy material having a fiber structure with high tensile strength.

  According to the invention described in the above item (5), the Al—Mg—Si based alloy material having a fiber structure with higher tensile strength can be obtained.

  According to the invention described in item (6), an Al—Mg—Si alloy material having a fiber structure with particularly high tensile strength can be obtained.

It is a model figure of the fiber structure of the Al-Mg-Si type alloy material of this application.

  The inventor of the present application, in the method for producing an Al-Mg-Si alloy material that is sequentially subjected to hot rolling and cold rolling, reduces the surface temperature of the alloy material after hot rolling to a predetermined temperature or less, By performing heat treatment as an aging treatment after the end of rolling and before the end of cold rolling, the value obtained by dividing 0.2% proof stress (MPa) by tensile strength (MPa) is large, and high electrical conductivity and good It has been found that an Al—Mg—Si alloy material having higher workability and higher strength can be obtained, leading to the invention of the present application.

  Hereinafter, the Al—Mg—Si based alloy sheet of the present application will be described in detail.

  In the Al—Mg—Si based alloy composition of the present application, the purpose of adding each element and the preferred content are shown.

  Mg and Si are elements necessary for the development of strength, and the respective contents thereof are Si: 0.2 mass% to 0.8 mass%, and Mg: 0.3 mass% to 1 mass%. preferable. If the Si content is less than 0.2% by mass or the Mg content is less than 0.3% by mass, the strength is lowered. On the other hand, if the Si content exceeds 0.8% by mass and the Mg content exceeds 1% by mass, the rolling load in hot rolling increases and the productivity decreases, and the formability of the resulting aluminum alloy sheet also increases. Deteriorate. The Si content is more preferably 0.2% by mass or more and 0.6% by mass or less, and particularly preferably 0.32% by mass or more and 0.60% by mass or less. The Mg content is more preferably 0.45% by mass or more and 0.9% by mass or less, and particularly preferably 0.45% by mass or more and 0.55% by mass or less.

  Fe and Cu are components necessary for molding, but if they are contained in a large amount, the corrosion resistance decreases. In the present application, the Fe content and the Cu content are preferably regulated to 0.5% by mass or less, respectively. The Fe content is more preferably regulated to 0.35% by mass or less, and particularly preferably from 0.1% by mass to 0.25% by mass. The Cu content is more preferably 0.1% by mass or less.

  In addition, various impurity elements are unavoidably contained in the alloy element, but Mn and Cr decrease conductivity and conductivity, and Zn increases in content and decreases in corrosion resistance of the alloy material. preferable. Ti has the effect of refining the crystal grains and preventing solidification cracking when casting the alloy into a slab, but if it is contained in a large amount, a large amount of crystallized products are produced. The workability, thermal conductivity, and electrical conductivity of the steel are reduced. Each content of Mn, Cr, Zn and Ti as impurities is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less.

  Other impurity elements other than the above may be contained, but the content of each other impurity element is preferably 0.05% or less.

  Next, processing steps for obtaining the Al—Mg—Si based alloy material defined in the present application will be described.

  The dissolved components are adjusted by a conventional method to obtain an Al—Mg—Si alloy ingot. The obtained alloy ingot is preferably subjected to a homogenization treatment as a step prior to heating before hot rolling.

  The homogenization treatment is preferably performed at 500 ° C. or higher.

  The heating before hot rolling is carried out in order to make the crystallized substance and Mg, Si dissolve in the Al—Mg—Si alloy ingot to form a uniform structure. Therefore, it is preferable to carry out at 450 ° C. or higher and 580 ° C. or lower, particularly preferably at 500 ° C. or higher and 580 ° C. or lower.

  The Al-Mg-Si-based alloy ingot is cooled after being homogenized, and may be heated before hot rolling, or the homogenization and heating before hot rolling may be performed continuously, In the preferable temperature range of the homogenization treatment and heating before hot rolling, the homogenization treatment and the heating before hot rolling may be combined and heated at the same temperature.

  It is preferable to chamfer the ingot to remove the impurity layer in the vicinity of the surface of the ingot before casting and before heating before hot rolling. The chamfering may be performed after casting and before homogenization treatment, or after homogenization treatment and before heating before hot rolling.

  The Al—Mg—Si alloy ingot after heating before hot rolling is hot rolled.

  Hot rolling consists of rough hot rolling and finishing hot rolling, and after performing rough hot rolling consisting of multiple passes using a rough hot rolling mill, a finishing hot rolling mill different from the rough hot rolling mill is used. Finish hot rolling using. In the present application, when the final pass in the rough hot rolling mill is the final pass of hot rolling, the finish hot rolling can be omitted.

  In the present application, finish hot rolling is performed once by introducing an Al—Mg—Si alloy material from one direction using a rolling mill in which a pair of upper and lower work rolls or two or more work rolls are continuously installed. It is carried out in the pass.

  When cold rolling is performed with a coil, an Al—Mg—Si alloy material after finish hot rolling may be wound with a winding device to form a hot rolled coil. When finishing hot rolling is omitted and the final pass of rough hot rolling is used as the final pass of hot rolling, the Al-Mg-Si alloy material is taken up with a winding device after the hot rolling. It may be a hot rolled coil.

  In rough hot rolling, after maintaining the state in which Mg and Si are dissolved in accordance with the solution treatment, cooling of the Al-Mg-Si alloy material by a rough hot rolling pass, or rough hot rolling is performed. The quenching effect can be obtained by the temperature drop due to forced cooling after the pass and after the pass.

  In the present application, among the plurality of passes of rough hot rolling, the surface temperature of the Al—Mg—Si alloy material immediately before the pass is 350 ° C. or more and 470 ° C. or less, and the Al—Mg—Si alloy material is cooled by the pass, or A pass having an average cooling rate of 50 ° C./min or more by the pass and forced cooling after the pass is called a control pass. The reason why the surface temperature of the Al—Mg—Si based alloy material immediately before the control pass is set to 350 ° C. or more and 470 ° C. or less is that the effect of quenching by rapid cooling in rough hot rolling is small below 350 ° C. This is because it is difficult to rapidly cool the Al-Mg-Si based alloy material with a rising path.

  The average cooling rate is the Al-Mg-Si alloy from the start of the control pass to the end when forced cooling is not performed in the control pass, and from the start of the control pass to the end of forced cooling when forced cooling is performed after the control pass. The value is obtained by dividing the temperature drop (° C) of the material by the time (minutes) required.

  Forced cooling after the control pass may be performed sequentially on the part after rolling while rolling the Al-Mg-Si alloy material, or after rolling the entire Al-Mg-Si alloy material. Also good. The method of forced cooling is not limited, but water cooling, air cooling, or coolant may be used.

  The control pass is preferably performed at least once, and may be performed a plurality of times. When performing the control pass a plurality of times, it is possible to select whether to perform forced cooling after each pass for each control pass. If the surface temperature of the Al—Mg—Si based alloy material immediately before the pass is 470 to 350 ° C. and the cooling rate is 50 ° C./min or more, the control pass can be performed a plurality of times. By lowering the temperature of the Al—Mg—Si alloy material to less than 350 ° C., quenching can be performed efficiently and effectively.

  In the present application, when forced cooling is not performed after the final pass of the rough hot rolling, the surface temperature of the Al-Mg-Si alloy material immediately after the final pass of the hot rolling is set as the temperature after the rough hot rolling, When forced cooling is performed after the final pass of rolling, the surface temperature of the Al—Mg—Si alloy material immediately after the end of forced cooling is set as the temperature after rough hot rolling.

In the present application, when finishing hot rolling is performed, finishing hot rolling ends. When finishing hot rolling is not performed, hot rolling ends with the end of the final pass of rough hot rolling, and immediately after the hot rolling ends. The surface temperature of the Al—Mg—Si based alloy material is preferably 170 ° C. or less. An effective quenching effect can be obtained by setting the temperature of the alloy material immediately after the end of hot rolling to 170 ° C. or less, and age hardening can be achieved during the subsequent heat treatment, and the conductivity can be improved.
If the surface temperature of the Al-Mg-Si alloy material immediately after the hot rolling is too high, the effect of quenching will be insufficient, and the strength will be improved even if the heat treatment is performed after the hot rolling and before the cold rolling. Is insufficient. The surface temperature of the aluminum plate immediately after completion of hot rolling is more preferably 150 ° C. or less, and particularly preferably 130 ° C. or less.

  In addition, when performing finish hot rolling after rough hot rolling, the surface temperature of the Al—Mg—Si based alloy plate immediately before finish hot rolling is: It is preferable that it is 280 degrees C or less.

  Similarly, when the final hot rolling is not performed and the final pass of the rough hot rolling is not the control pass, the surface temperature of the Al—Mg—Si alloy plate immediately before the final hot hot rolling pass is 280 ° C. or less. preferable.

  On the other hand, when final hot rolling is not performed and the final pass of rough hot rolling is a control pass, the control pass becomes the final pass of hot rolling, so the Al—Mg—Si system immediately before the final pass of hot rolling Control pass so that the surface temperature of the alloy plate is 470 to 350 ° C., and the surface temperature of the alloy plate is 170 ° C. or less at a cooling rate of 50 ° C./min or more by rolling or forced cooling after rolling and rolling. It is preferable to implement.

  A heat treatment is applied to the Al—Mg—Si based alloy material after the hot rolling and before the cold rolling to age-harden and improve the conductivity.

  In the present application, the heat treatment of the Al—Mg—Si alloy material after the end of hot rolling and before the end of cold rolling may be performed at a temperature of 120 ° C. or more and less than 200 ° C. in order to obtain the effects of age hardening and conductivity improvement. preferable. The temperature of the heat treatment is more preferably 130 ° C. or higher and 190 ° C. or lower, and particularly preferably 140 ° C. or higher and 180 ° C. or lower.

  The time for heat treatment of the Al—Mg—Si based alloy material performed at a temperature of 120 ° C. or more and less than 200 ° C. after the end of the hot rolling and before the end of the cold rolling is not particularly limited. What is necessary is just to adjust time at predetermined temperature so that it may be obtained, for example, heat processing may be implemented by adjusting time in the range of 1 to 12 hours.

  After the heat treatment, by cold rolling, the work hardening is achieved and the strength is further improved.

  The heat treatment is preferably performed after the end of hot rolling and before the start of cold rolling in order to enhance the effect of improving the strength of the age-hardened Al—Mg—Si based alloy material by cold rolling.

  The Al—Mg—Si alloy material having a predetermined thickness is obtained by cold rolling after the heat treatment. The cold rolling after the heat treatment is preferably performed at a rolling rate of 60% or more in order to improve strength and improve workability. The rolling rate of the Al—Mg—Si alloy material by cold rolling after the heat treatment is further preferably 70% or more, and particularly preferably 80% or more.

  The Al—Mg—Si alloy material after cold rolling may be cleaned as necessary.

  When the workability of the Al—Mg—Si based alloy material is further emphasized, final annealing may be performed after cold rolling. The final annealing is preferably performed at 250 ° C. or lower, more preferably 220 ° C. or lower, particularly 180 ° C. or lower in order to prevent the strength of the Al—Mg—Si based alloy material from becoming too low.

  What is necessary is just to adjust the time of the said last annealing so that required workability and intensity | strength may be obtained, for example, what is necessary is just to select with the temperature of final annealing in the range of 1 to 10 hours.

  The production of the Al—Mg—Si based alloy material of the present application may be performed by a coil or a single plate. Further, the Al—Mg—Si based alloy material may be cut in an arbitrary step after the cold rolling, and the step after the cutting may be performed with a single plate, or may be slit and formed depending on the application.

  According to the above production method, an Al—Mg—Si based alloy material that can improve strength while obtaining high electrical conductivity and is excellent in workability despite being high in strength can be obtained.

  The Al—Mg—Si alloy material of the present application has a fiber structure. The fiber structure is a metal structure stretched by plastic working.

  FIG. 1 shows a model diagram of the fiber structure of the Al—Mg—Si alloy material of the present application.

  As shown in FIG. 1, in the present application, the metal structure is exposed so that the normal of the observation surface is perpendicular to both the processing direction vector of the Al—Mg—Si alloy material and the normal direction vector of the processing surface, A metal structure in which the grain boundary in the normal direction of the processed surface of the metal structure of the observation surface observed with an optical microscope is 3 lines / 100 μm or more and the grain boundary having a length in the processing direction of 300 μm or more is defined as a fiber structure. . When the plastic processing is rolling, the processing direction is the rolling direction, the processing surface is the rolling surface, and the observation surface is a cross section in the thickness direction cut in parallel to the rolling direction.

  As a method of exposing the metal structure, the surface of the Al-Mg-Si alloy material whose normal is perpendicular to both the processing direction vector of the Al-Mg-Si alloy material and the normal direction vector of the processing surface is polished. Then, a method of anodizing the polished surface can be exemplified. Barker's solution (3% borohydrofluoric acid aqueous solution) can be preferably used as the anodizing solution.

  The electrical conductivity of the Al—Mg—Si based alloy material of the present application is defined as 54% IACS or more, and the tensile strength is defined as 170 MPa or more. The tensile strength is preferably 200 MPa or more, more preferably 220 MPa or more, and particularly preferably 250 MPa or more and 280 MPa or more. The value obtained by dividing the 0.2% proof stress (MPa) of the Al—Mg—Si based alloy material of the present application by the tensile strength (MPa) is defined as 0.91 or more and 1.00 or less. Al-Mg-Si based alloy which satisfies the value obtained by dividing 0.2% proof stress (MPa) by tensile strength (MPa) and tensile strength, and has excellent bending workability by having a fiber structure. Become a material. The value obtained by dividing the 0.2% proof stress (MPa) by the tensile strength (MPa) is more preferably 0.92 or more and 1.00 or less, and particularly preferably 0.93 or more and 1.00 or less.

  Examples of the present invention and comparative examples are shown below.

  Aluminum alloy slabs having different chemical compositions shown in Table 1 were obtained by the DC casting method.

[Example 1]
The aluminum alloy slab having the chemical composition number 1 in Table 1 was chamfered. Next, the homogenized treatment at 560 ° C. for 5 hours was performed on the alloy slab after chamfering in a heating furnace, and then the pre-hot rolling at 540 ° C. for 4 hours was performed by changing the temperature in the same furnace. After heating before hot rolling, a 540 ° C. slab was taken out from the heating furnace, and rough hot rolling was started. After the thickness of the alloy plate during the rough hot rolling reaches 25 mm, the final pass of the rough hot rolling is performed at an average cooling rate of 80 ° C./minute from the alloy plate temperature of 450 ° C. immediately before the pass, An alloy plate having a hot rolling temperature of 221 ° C. and a thickness of 12 mm was obtained. In the final pass of the rough hot rolling, the alloy plate was moved while rolling, and forced cooling was performed by water cooling in which water was sprayed on the alloy plate sequentially from above and below the portion of the rolled alloy plate.

  After the rough hot rolling, the alloy plate was subjected to finish hot rolling from a temperature immediately before finish hot rolling of 219 ° C. to obtain an alloy plate having a thickness of 7.0 mm. The temperature of the alloy sheet immediately after finish hot rolling was 110 ° C. The alloy plate after finish hot rolling was heat treated at 170 ° C. for 5 hours, and then cold rolled at a rolling rate of 98% to obtain an aluminum alloy plate having a product plate thickness of 0.15 mm.

[Examples 2 to 42, Comparative Examples 1 to 6]
After chamfering the aluminum alloy slab described in Table 1, treatment was performed under the conditions described in Tables 2 to 6 to obtain an aluminum alloy plate. As in Example 1, in all Examples and Comparative Examples, homogenization treatment and heating before hot rolling are continuously performed in the same furnace, and forced cooling after the final pass of rough hot rolling is performed while rolling. Either water cooling in which the alloy plate is moved and water is sprayed on the alloy plate in order from the top and bottom of the rolled alloy plate portion or air cooling in which the air is cooled after completion of the final hot-rolling pass is selected. In some examples, final annealing was performed after cold rolling.

  In Example 18, the final pass of the rough hot rolling was used as the final pass of the hot rolling, and the finish hot rolling was not performed.

  In Comparative Example 1 and Comparative Example 2, a solution treatment was performed in which heat treatment was performed at 550 ° C. for 1 minute during the cold rolling, followed by cooling at a rate of 5 ° C./second or more. In Comparative Example 1 and Comparative Example 2, the cold rolling rate is the total rolling rate of the cold rolling before and after the solution treatment, and the cold rolling after the solution treatment is based on the thickness of the alloy material after the solution treatment. The cold rolling rate was 30%.

  The tensile strength, 0.2% yield strength, electrical conductivity, and workability of the obtained alloy plate were evaluated by the following methods.

  Tensile strength and 0.2% proof stress were measured for JIS No. 5 test pieces at ordinary temperature by a conventional method.

The electrical conductivity was determined as a relative value (% IACS) when the electrical conductivity of annealed standard annealed copper (volume low efficiency 1.7241 × 10 ⁻² μΩm) adopted internationally was 100% IACS.

  As for workability, when the bending angle is 90 °, the thickness of the alloy plate is 0.4 mm or more, the thickness of each alloy plate is bent inside radius, and when the thickness of the alloy plate is less than 0.4 mm, the bending inside The bending test by the 6.3 V block method of the JIS Z 2248 metal material bending test method was carried out with the radius set to 0, and the case where no crack was generated was evaluated as ◯, and the case where the crack was generated was evaluated as ×.

  In Examples and Comparative Examples, when the metal structure of the cross section of the Al-Mg-Si alloy plate in the thickness direction cut parallel to the rolling direction is exposed, the rolling surface normal of the metal structure observed with an optical microscope The metal structure in which the grain boundary in the direction is 3 lines / 100 μm or more and the grain boundary having a length in the rolling direction of 300 μm or more is defined as the fiber structure.

  As a method of exposing the metal structure, an Al-Mg-Si alloy plate cut in parallel to the rolling direction is polished with emery paper, subjected to rough buffing and final polishing, and then washed with water and dried. Furthermore, a method of applying anodizing treatment in a Barker solution (3% aqueous borofluoric acid solution) under conditions of bath temperature: 28 ° C., applied voltage: 30 V, applied time: 90 seconds was applied.

  Tensile strength, 0.2% proof stress, 0.2% proof stress (MPa) divided by tensile strength (MPa), conductivity and workability evaluation results, and Al—Mg—Si based alloy sheet Tables 7 and 8 show whether or not they have a fiber structure.

  The Al-Mg-Si system described in the examples satisfying the chemical composition, tensile strength, 0.2% proof stress (MPa) divided by tensile strength (MPa) and electrical conductivity, and having a fiber structure. The alloy material also has good workability. On the other hand, Comparative Example 1 and Comparative Example 2 in which solution treatment was performed during the cold rolling did not have a fiber structure, the conductivity was inferior to that of the present example, and the chemical composition did not satisfy the specified range of this example. In Comparative Example 6, at least one of the tensile strength and the electrical conductivity is inferior to that of the example, and some of them are inferior in workability.

Claims (6)

  A fiber structure having a tensile strength of 170 MPa or more, a value obtained by dividing 0.2% proof stress (MPa) by tensile strength (MPa) of 0.91 or more and 1.00 or less, and a conductivity of 54% IACS or more. Al-Mg-Si based alloy material.   The chemical composition contains Si: 0.2-0.8% by mass, Mg: 0.3-1% by mass, Fe: 0.5% by mass or less and Cu: 0.5% by mass or less, the balance Al and The Al—Mg—Si based alloy material according to claim 1, comprising inevitable impurities.   The Al—Mg—Si based alloy material according to claim 2, wherein Mn, Cr, Zn, and Ti as impurities are each regulated to 0.1 mass% or less.   The Al-Mg-Si based alloy material according to any one of claims 1 to 3, wherein the tensile strength is 200 MPa or more.   The Al-Mg-Si alloy material according to any one of claims 1 to 3, wherein the tensile strength is 220 MPa or more.   The Al-Mg-Si alloy material according to any one of claims 1 to 3, wherein the tensile strength is 250 MPa or more.

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