JP2012062517A - Aluminum alloy excellent in thermal conductivity, strength and formability and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-Mg-Si-based aluminum alloy rolled sheet excellent in thermal conductivity, strength and formability and a method of manufacturing the same by a simple and economical process without damaging a performance as a component for heat radiation.SOLUTION: An Al-Mg-Si-based alloy, which contains 0.1 to 0.34 mass% (described as%, hereinafter) Mg, 0.2 to 0.8% Si, and 0.22 to 1.0% Cu with the balance being Al and inevitable impurities and whose Si/Mg content ratio is ≥1.3, is turned to an ingot having a thickness of ≥250 mm by semicontinuous casting, subjected to hot rolling through preheating at the temperature of 400 to 540°C and cold rolling with the rolling reduction of 50 to 85%, and then annealed at the temperature of 140 to 280°C, to obtain the Al-Mg-Si-based alloy rolled sheet which has a fiber structure, and whose electric conductivity is ≥57.5%IACS and tensile strength is ≥180 N/mm.

Description

  TECHNICAL FIELD The present invention relates to an Al—Mg—Si alloy rolled plate excellent in thermal conductivity, strength and formability, and a method for producing the same at low cost, and in particular, electronic video equipment such as plasma displays and liquid crystal displays, personal computers, etc. The present invention relates to an Al—Mg—Si alloy rolled plate suitable as a material for parts that require heat diffusibility, such as heat sinks, housings, supports, and substrates of electronic information devices and household appliances.

  Electronic devices and electrical appliances that use a large amount of electronic components that generate heat are being further enhanced in function, size, and thickness, and the importance of thermal design that prevents an increase in internal temperature is increasing.

  For example, since a plasma display is thin and has a structure that can be hung on a wall, video components and electronic components are densely integrated. A video component is an aggregate of light emitting elements, and since a high voltage is loaded, it generates a large amount of heat and raises the temperature of the electronic component. This causes noise and, in the worst case, causes failure. In order to prevent this failure, a heat radiating plate is installed between the video component and the electronic component to provide a heat dispersion / diffusion function. The heat radiating plate is often formed from a plate material having a thickness of about 0.5 to 2.0 mm, and the necessary performance of the material is high thermal conductivity, high strength, and good formability.

  Originally, aluminum has better thermal conductivity than steel, is lighter, and includes heat sinks for LCDs, personal computers, portable electronic devices, automotive electronic devices, housings, supports, and substrates, including heat sinks for plasma displays. It has properties suitable for applications where thermal diffusivity is important. However, among aluminum materials, pure aluminum, that is, 1000 series alloys represented by JIS1100, 1050, 1070 alloys, etc. have high thermal conductivity but low strength and are insufficient in strength as molded parts such as housings and supports. It is.

  On the other hand, Al-Mg-based JIS5052 alloy and Al-Mn-based 3003 alloy are typical examples of materials having higher strength, but their thermal conductivity is lower than that of 1000-based alloys, and thermal diffusivity. Is not suitable as a material for parts that are particularly required. In view of this, an aluminum alloy sheet having good heat transferability and strength is required as a heat countermeasure for electronic devices that are becoming more highly functional, smaller and thinner. In addition, electronic devices used are widely used around the world. From the viewpoint of energy and cost required for plate production, this is a simplified process that does not include an extra heat treatment process and is suitable for mass production. The process is required to achieve high heat transfer properties and strength.

  As a material having such high thermal conductivity and high strength, use of an Al—Mg—Si based alloy is conceivable. In general, there is a significant positive correlation between electrical conductivity and thermal conductivity, and it can be said that the higher the electrical conductivity, the higher the thermal conductivity. Originally, Al-Mg-Si-based alloys include 6101 alloy having excellent conductivity as a JIS standard alloy for high-strength electric wires. According to Non-Patent Document 1, the composition is Si: 0.3 to 0.7% by mass (hereinafter referred to simply as “%” for the alloy composition), Mg: 0.35 to 0.8%, Fe : 0.5% or less, Cu, Zn: 0. 1% or less, Mn, Cr: 0.03% or less for each, B: 0.06% or less.

Non-Patent Document 2 discloses an alloy that is a T6 material that has undergone a solution treatment and a precipitation treatment and has a conductivity as high as 57% IACS and that is equivalent to that of pure aluminum-based 1100-H18. The normal use form of this alloy is an extruded or drawn wire, which cannot be simply replaced with the strength of the plate material, but has a high strength that cannot be achieved with a pure aluminum system at 221 N / mm ² for the T6 material. If such a characteristic can be realized as a plate material, the thermal conductivity is good, so that it is considered suitable as a material for parts that require the above-mentioned thermal diffusivity.

  However, in order to simply use this alloy as a plate material, costly heat treatment such as solution treatment is required, and the manufacturing process becomes complicated. Although the formability deteriorates after the precipitation treatment for increasing the strength, it is also complicated to perform the precipitation treatment after the molding to avoid it.

  On the other hand, techniques for producing an Al—Mg—Si alloy having excellent thermal conductivity such as 6101 alloy as a plate material have been proposed in several known documents. The invention described in Patent Document 1 contains Si: 0.2 to 0.8%, Mg: 0.3 to 0.9%, Fe: 0.35% or less, and Cu: 0.20% or less as a composition A method for obtaining an Al—Mg—Si alloy rolled sheet having excellent thermal conductivity and strength by regulating the hot rolling conditions is shown.

  The alloy composition itself is a technique that makes it possible to omit the independent solution treatment by giving the same effect as the solution treatment to hot rolling, although the range of the 6101 alloy is only slightly expanded. . However, it is a very difficult restriction for the optional pass process during hot rough rolling (material temperature 350-440 ° C. before pass, cooling rate between passes 50 ° C./min or more, pass up material temperature 250-340 ° C., up In order to implement this, enormous capital investment costs are required.

  In addition, the inventions described in Patent Documents 2 and 3 are directed to an alloy composition similar to the 6101 alloy as in Patent Document 1, and require additional intermediate annealing in the process after hot rolling. Further, there is a claim for controlling the material temperature before an arbitrary hot rolling pass and the cooling rate after the hot rolling pass, and this control is performed in all the embodiments, and a complicated process is taken.

  In the invention described in Patent Document 4, the composition is Si: 0.2 to 1.5%, Mg: 0.2 to 1.5%, Cr: 0.02 to 0.1%, Fe: 0.3% Hereinafter, it is about an Al-Mg-Si alloy with Ti: 0.015% or less, and the case where other selective elements such as Cu 0.01 to 1% are added is also described. One form of the process of this patent is that after hot rolling, a solution treatment at 500 to 570 ° C. is performed in the middle of cold rolling, and further heat annealing at 170 to 210 ° C. after cold rolling under specified conditions. It is a complicated thing to do.

  In Patent Document 4, other forms of the process, that is, after hot rolling, without performing intermediate annealing in the middle of cold rolling, cold rolling to the final plate thickness, and performing annealing to 180 to 300 ° C, Also disclosed is a method for obtaining a plate material having an excellent thermal conductivity of 53% IACS or more. This can be said to be a simple manufacturing method with no restrictions on conditions in the hot rolling process, solution treatment, and annealing in the middle of the cold rolling process, but this patented method is stable for large materials suitable for mass production. No provisions have been made to achieve high heat transfer and strength, and the technology has not been completed.

  In the invention described in Patent Document 5, the composition is Si: 0.2 to 1.5%, Mg: 0.2 to 1.5%, Ti: more than 0.015 to 0.2%, and Mn or Cr. A case where an Al-Mg-Si-based alloy containing a trace amount is targeted and another selective element such as Cu 0.01 to 1% is added is also described. Although it has relatively high thermal conductivity and excellent strength and moldability, solution treatment (500 to 570 ° C., cooling rate of 1.0 ° C./sec or more) is performed by a continuous annealing method in the manufacturing process. It will also be expensive.

  The inventions described in Patent Documents 6 and 7 show a simple manufacturing method without any restrictions in the hot rolling process, solution treatment, and aging annealing. However, it has been found that the described components can achieve further higher thermal conductivity, specifically, a rolled sheet having an electrical conductivity of 57.5% IACS or more and excellent strength.

Japanese Patent No. 3496263 JP 2003-321755 A JP 2009-102737 A Japanese Patent Laying-Open No. 2005-8926 JP 2005-264174 A JP 2008-248297 A JP 2009-242813 A

Aluminum handbook 5th edition METALS HANDBOOK TENTH EDITION VOL. 2

  The present invention was made against the background of the above circumstances, and an Al-Mg-Si alloy excellent in thermal conductivity, strength, and formability by a simple and economical process without impairing the performance as a heat dissipation component. It aims at providing a rolled sheet and its manufacturing method.

  The inventors of the present invention should solve the above-mentioned problems, and are an Al-Mg-Si-based alloy that is excellent in thermal conductivity, strength, and formability by a simple and low-cost production method that satisfies the following requirements. The earnest examination was carried out to obtain a rolled sheet.

・ Assuming that semi-continuous casting → facing → preheating → hot rolling → cold rolling → annealing
・ No need for independent homogenization before chamfering,
・ No complicated temperature control is required during hot rolling.
・ No need for intermediate annealing,
・ Cold rolling within 3 consecutive passes,
・ No solution treatment at any point in the process,
-Reduce the preheating temperature for hot rolling to less than 560 ° C.

  In addition, even if a small size ingot produces good characteristics, it is not desirable to set the material so that the characteristics increase or the characteristics decrease or become unstable. It is necessary to stably obtain a material with good thermal conductivity, strength and formability on a mass production scale, and good characteristics can be obtained with a plate material manufactured from an ingot of mass production scale with a thickness of at least 250 mm or more. Is required. It is also a necessary condition that there is no surface defect of the plate material.

The present invention has been made to satisfy the above preconditions,
1st invention of Claim 1 is an Al-Mg-Si type alloy rolled sheet, Mg is 0.1-0.34%, Si is 0.2-0.8%, Cu is 0.22-0.2%. 1.0% content, the balance is made of Al and inevitable impurities, Si / Mg content ratio is 1.3 or more, has a fiber structure, conductivity is 57.5% IACS or more, and tensile strength is 180 N It is an Al—Mg—Si based alloy rolled plate excellent in thermal conductivity, strength and formability, characterized by being / mm ² or more.

  As described above, since there is generally a positive correlation between the thermal conductivity and conductivity of an aluminum alloy, the thermal conductivity of the present invention was evaluated by measuring the conductivity as an alternative characteristic. Therefore, in the following description, where an effect or influence on “conductivity” is described, it indicates that there is an equivalent effect or influence on “thermal conductivity”.

  According to a second aspect of the present invention, an Al—Mg—Si alloy having the component according to the first aspect is made into an ingot having a thickness of 250 mm or more by semi-continuous casting, and a preliminary operation at a temperature of 400 to 540 ° C. In the method for producing an Al-Mg-Si alloy sheet, which is subjected to hot rolling through heating and cold rolling at a reduction rate of 50 to 85%, followed by annealing at a temperature of 140 to 280 ° C. is there.

  According to the present invention, it is possible to obtain an Al—Mg—Si alloy rolled sheet having excellent thermal conductivity, strength, and formability by a simple and economical manufacturing process with appropriate alloy components and manufacturing processes. It is possible to reduce the manufacturing cost. Moreover, the above-mentioned good characteristics can be stably obtained by using a large ingot suitable for mass production.

Hereinafter, the contents of the present invention will be described in more detail.
In the present invention, an Al—Mg—Si based alloy is used as a plate material in a simple process without solution treatment, and a material design different from the conventional one is performed in order to obtain good thermal conductivity and strength. In order to increase the conductivity, it is necessary to reduce the solid solution amount of additive elements Mg, Si, and Cu as much as possible. Since these elements do not have sufficient precipitation time at the time of casting, a considerable amount is dissolved in the ingot. Therefore, in order to achieve high conductivity, it is required to sufficiently deposit them in a later step.

Next, the reasons for limiting the alloy components in the present invention will be described.
Various amounts of Mg, Si, and Cu in the alloy and respective abundance ratios were changed, and conditions for improving heat conductivity, strength and formability stably were examined, and an appropriate alloy composition was selected. About Mg, Si, and Cu, it is necessary to select not only the addition amount but also the respective amount ratios appropriately.

Mg: 0.1 to 0.34%
Mg is an essential additive element useful for ensuring the strength and formability of the alloy. However, it has a relatively wide solid solubility limit and also has a great effect of lowering the electrical conductivity when dissolved. In the case where the content exceeds 0.34%, assuming the simple process of the present invention, there is a problem that the decrease in the conductivity is large and the characteristic variation in the mass production scale material is also large. On the other hand, if it is less than 0.1%, it is difficult to ensure the strength. Therefore, the range of Mg amount is 0.1 to 0.34%, and the preferable range of Mg amount is 0.15 to 0.3%. As will be described later, there is an appropriate range for Mg with respect to the amount of Si.

Si: 0.2 to 0.8%
Si is an essential element for ensuring the strength and formability of this alloy. If it exceeds 0.8%, the electrical conductivity will decrease, and other additive elements and coarse intermetallic compounds will be produced, making it difficult to ensure moldability. On the other hand, if it is less than 0.2%, it becomes difficult to ensure strength, and further, an intermetallic compound with other elements is not formed, and the amount of solid solution increases and the conductivity decreases. Therefore, the range of Si amount is 0.2 to 0.8%. However, the intermetallic compound mentioned here is not a fine compound that contributes to an increase in strength obtained mainly by aging treatment, but a crystallized product produced during alloy casting. A preferred Si content range is 0.25 to 0.7%.

Cu: 0.22-1.0%
Cu is an essential element for securing the strength of the alloy. If it exceeds 1.0%, it is difficult to ensure conductivity and moldability. On the other hand, if it is less than 0.22%, it is difficult to ensure the strength. Therefore, the range of Cu content is 0.22 to 1.0%. A more preferable Cu amount is 0.25 to 0.8%.

Si / Mg content ratio: 1.3 or more In the present invention, the content ratio of Mg, Si and Cu is specified, and if it is within this range, an aluminum alloy plate having high conductivity can be obtained. When the Si / Mg ratio is lower than this, that is, when the Si amount is relatively low, the amount of intermetallic compound containing Mg and Si is small, so that the amount of solid solution Mg in the final plate material increases, so The rate tends to be low. Moreover, since this ratio is low, there arises a problem that the characteristic variation due to the position in the mass production scale material increases. This is an alloy composition range with a relatively low Mg content of the present invention, and when the Si / Mg ratio is low, rapid precipitation is unlikely to occur. This is because there is a high possibility that the states are different.

  Si also has an effect of lowering the electrical conductivity when the solid solution amount increases, but the electrical conductivity reducing effect per unit solid solution amount is smaller than that of Mg. For this reason, even if both elements are slightly dissolved by containing a relatively large amount of Si, the effect of reducing the solid solution of Mg is great, which works advantageously for high conductivity. Some solid solution of Si also contributes to strength improvement.

  Moreover, the upper limit of Si / Mg content ratio can be set to 8.0, for example. Beyond this, the amount of Si inevitably exceeds the specified range, resulting in a decrease in conductivity.

  In addition to the specified elements, there is Fe as an element generally added to or contained in the aluminum alloy. Fe is an impurity contained in aluminum scrap or aluminum ingot, and usually about 0.1% is contained. However, if it is contained in a large amount, a coarse Al—Fe-based intermetallic compound is produced, and the formability deteriorates. Also, the conductivity is lowered. Therefore, it is desirable that the Fe content be restricted to 0.35% or less.

Other elements include Ti and B. Ti is effective in refining the crystal grain of the ingot and prevents ingot cracking. If the amount added is too large, Al ₃ Ti crystallizes, causing a decrease in electrical conductivity and deterioration in formability. On the other hand, if the addition amount is too small, the effect of miniaturization cannot be obtained sufficiently. For the above reasons, the amount of Ti added is generally regulated to about 0.005 to 0.1%.

Further, in order to enhance the effect of refining the crystal grains of the ingot, B is added in combination with Ti. In that case, the addition amount is too large when the TiB ₂ is generated bending of B deteriorates. On the other hand, if the amount of addition of B is too small, an effect cannot be sufficiently obtained for crystal grain refinement. Generally, it is regulated to about 0.0001 to 0.05%.

  Mn, Zr, Cr, and the like other than those described above are alloy elements that are generally added for recrystallized grain refinement, but they have a great influence on the electrical conductivity and are preferably not added. However, if the content is up to 0.05%, which is the upper limit value of general impurity elements, the performance of the Al—Mg—Si alloy rolled sheet of the present invention is not impaired.

Next, various characteristics of the present invention will be described. In the present invention, the electrical conductivity after annealing is regulated to 57.5% IACS, and the tensile strength is regulated to 180 N / mm ² or more. When the electrical conductivity is lower than 57.5% IACS, the thermal conductivity as a heat radiating component is insufficient. Therefore, 57.5% IACS or more is preferable. In addition, as described above, the reason why the thermal conductivity is replaced with the electrical conductivity is explained because there is generally a positive correlation between the thermal conductivity and the electrical conductivity of the aluminum alloy.

On the other hand, if the tensile strength is lower than 180 N / mm ² , the strength as a heat radiating component becomes insufficient. Therefore, it was set to 180 N / mm ² or more. A1100, which is a typical pure aluminum material, has an electrical conductivity of 57% IACS and a tensile strength of 165 N / mm ² in the state of H18 that has been increased in strength by work hardening. The above conductivity (thermal conductivity) means high strength that cannot be achieved with pure aluminum.

  Next, the manufacturing method of the Al-Mg-Si type alloy rolled sheet of this invention is demonstrated. First, an ingot having a thickness of 250 mm or more of an Al—Mg—Si based alloy having the alloy component is obtained by a semi-continuous casting method according to a conventional method. The regulation of the ingot size is necessary for efficient mass production.

  Prior to hot rolling, homogenization is often performed for the purpose of improving performance and reducing performance variations, but in the present invention, independent homogenization is not performed before chamfering of the ingot. The heat treatment for the above purpose is replaced by carrying out hot rolling preheating at a temperature of 400 to 540 ° C. after chamfering. If it is less than 400 ° C., it is not suitable because subsequent hot rolling becomes difficult, and if it exceeds 540 ° C., local melting may occur in the ingot, which is inappropriate. The preheating temperature for hot rolling is less than 560 ° C., which is desirable for further reducing cost and energy consumption, and there is no problem in characteristics.

  Hot rolling may be performed by a method according to a conventional method, and the hot rolling conditions are not particularly limited. In general, hot finish rolling often has an end temperature of 300 ° C. or less at a plate thickness of 10 mm or less.

  After the hot rolling is finished, cold rolling is performed. This is done to improve the strength by processing the hot rolled sheet. This cold rolling is performed at a rolling rate of 50 to 85%. From an economical point of view, cold rolling is performed within 3 passes, preferably within 2 passes, and no intermediate annealing is performed. If the rolling rate of cold rolling is less than 50%, high strength cannot be secured. On the other hand, if it exceeds 85%, a herringbone having a surface pattern defect is likely to occur when it is carried out with an economical number of passes, which is inappropriate.

  The alloy according to the present invention is characterized in that the structure after the final annealing is a fiber structure. The fiber structure is a structure in which dislocations are concentrated at high density in crystal grains stretched by plastic working applied during hot rolling or cold rolling. Since the alloy of the present invention is annealed under conditions that do not cause partial or complete recrystallization after cold rolling, it has a fiber structure after annealing and can maintain high strength.

  After cold rolling, annealing is performed in the range of 140 to 280 ° C. Annealing below 140 ° C. results in insufficient softening and insufficient bendability. In annealing at a temperature exceeding 280 ° C., the strength becomes insufficient because of excessive softening. The annealing time is less effective when the time is shorter than 1 hour, and softening is saturated when the time is longer than 48 hours, which is economically disadvantageous.

  The annealing is performed to soften the rolled sheet, but is not performed for age hardening as in a normal 6000 series alloy. In heat-treatable aluminum alloys including 6000 series alloys, solution treatment is generally performed and age hardening is performed to ensure strength and electrical conductivity. That is, by performing the solution treatment, the subsequent heat treatment exceeding 150 ° C. necessarily has an effect as an aging treatment. However, since the solution treatment is not performed in the present invention, the heat treatment in the temperature range described above is performed simply to anneal and soften the alloy as described above.

  Moreover, in this manufacturing method, it becomes possible to achieve cost reduction by not performing solution treatment.

  The alloys shown in Alloy Nos. 1 to 16 in Table 1 were melted by a conventional method, and each was cast into an ingot having a thickness of 450 mm, a width of 1080 mm, and a length of 2800 mm by a semi-continuous casting method. In all of the following tables, conditions that deviate from the provisions of the present invention are shown in italics and distinguished.

  The obtained ingot was chamfered about 15 mm on the surface and preheated to obtain a plate material (coil) having a plate thickness of 1 mm or 1.5 mm and a width of 1000 mm in the steps of hot rolling, cold rolling and final annealing. Table 2 shows the manufacturing process conditions. The holding time of these hot rolling preheating temperatures was 4 to 6 hours, and the material temperature at the time of hot rolling was in the range of 250 to 300 ° C. All of the cold rolling was performed in two passes, and the rolling rate in Table 2 is the total rolling reduction based on the plate thickness before cold rolling. The material for evaluation was taken from the center of the length and width of the coil.

Ｎｏ．１〜１６は微細化剤成分として他にＴｉ ０．０１％， Ｂ０．００２％を含む。

No. 1-16 contain 0.01% of Ti and 0.002% of B in addition as a fine agent component.

  Conductivity is taken in parallel with the rolling direction by taking a specimen of plate thickness x 50 mm x length 1000 mm (measurement reference length 500 mm), measuring the specific resistance value by the double bridge method, and setting the specific resistance value of standard copper as 100 Calculated.

  In addition, the tensile strength was determined in the direction perpendicular to the rolling direction using a No. 5 tensile test piece defined in JISZ2201.

  The alloy of the present invention is often used after being formed. Therefore, a 90 ° bending test was performed on a No. 3 bending test piece defined in JIS 2204 cut in a direction perpendicular to the rolling direction (a direction inferior in bendability), and the result was regarded as formability. The 90 ° bending test was performed with an inner bending radius of 2.0 mm, and was observed with a 10-fold magnifier. If no crack was generated, the test was accepted (O), and if the crack was generated, the test was rejected (X).

  Table 3 shows the evaluation results of conductivity, tensile strength, and formability.

In Table 3, all of the invention examples satisfying the alloy components and manufacturing process conditions defined in the present invention have a conductivity of 57.5% IACS or more, a tensile strength of 180 N / mm ² or more, and good formability. It is clear that the material has both conductivity, that is, thermal conductivity, strength, and moldability.

  On the other hand, 1-G of Comparative Example is an example in which the fiber structure could not be obtained because the cold rolling rate at the time of cold rolling was insufficient, the tensile strength was lowered, and the strength could not be secured.

  1-H is an example in which the final annealing temperature was too low, so that almost no recovery occurred and formability could not be ensured.

  1-I is an example in which the final annealing temperature is too high and partial or complete recrystallization occurs, resulting in insufficient strength.

  1-J was an example in which the cold rolling rate was too high, and an abnormal pattern (herringbone) was generated on the surface after cold rolling, so it was not subjected to subsequent evaluation.

  1-K was an example in which the hot rolling preheating temperature was too low, and material cracking occurred during hot rolling, so it was not subjected to subsequent evaluation. In addition, 1-L is a case where the preheating of the hot rolling is performed at a temperature higher than a specified temperature, and local melting occurs in the ingot and a uniform structure cannot be obtained. We did not use for evaluation.

  Moreover, since 10-A does not satisfy the Si / Mg ratio which prescribes | regulates too little Si amount, the electrical conductivity fell.

  Since 11-A had too much Si, the conductivity decreased. Moreover, many intermetallic compounds were produced | generated and the bendability also fell.

  The strength of 12-A was lowered because the amount of Mg was too small.

  Since 13-A contained too much Mg, the conductivity decreased.

  In 14-A, the amount of Cu was too small, so the strength was lowered.

  Since the amount of Cu in 15-A was too large, the conductivity decreased. Moreover, the bendability has also deteriorated.

  16-A has a Si / Mg content ratio of 1.00, which is lower than 1.3 defined in the present invention. The conductivity is below 57% IACS.

  For comparison, the evaluation results of commercial products A1100P-H18 and A3003P-H18 are also shown in Table 3. In particular, the former has insufficient strength, and the latter has insufficient conductivity, so that both have insufficient performance as heat-dissipating component materials. Also from this, it is clear that the Al—Mg—Si alloy rolled sheet of the present invention is a material having conductivity, that is, thermal conductivity, strength, and formability.

  Table 4 shows examples and comparative examples when only the alloy composition is further changed. Here, a 400 × 1080 × 2500 mm ingot created by a mass production scale semi-continuous casting apparatus was used, and it was subjected to evaluation as a plate material having a thickness of 1 mm under the same conditions as in Step A (Table 2) of Example 1. The material for evaluation was taken from the center of the length and width of the coil.

  The alloys in Table 4 contain Fe 0.12 to 0.14% in addition to the indicated composition, include 0.01% Ti and B0.002% derived from the casting finer, and the balance is Al and other inevitable Made of typical impurity elements.

Inventive examples include the upper and lower limits of the composition-defined range, but all show good values of electrical conductivity of 57.5% or more and tensile strength of 180 N / mm ² or more, and have excellent electrical conductivity, that is, thermal conductivity and strength. It has become a material. In the comparative example, either strength or conductivity is inferior.

  The alloys shown in Table 5 were made into ingots of 250 × 1050 × 2500 mm or 400 × 1050 × 2500 mm using a mass production scale semi-continuous casting apparatus. This was hot rolled, cold rolled, and finally annealed under the production conditions (M, N, O) shown in Table 6 to obtain a plate having a thickness of 1 mm and a width of 970 mm. About the coil of about 500 m in length of these materials, electrical conductivity and intensity | strength were evaluated in the front end, the center of length, the width center of the rear end, and the width end. In addition, the material of the front end and the rear end means the front end and the rear end of the normal use portion excluding the irregular shape of the end and the unsteady speed range at the start and end of rolling.

  For comparison, a semi-continuous casting apparatus on an experimental scale was used to obtain an ingot of 80 × 200 × 250 mm, and a plate having a thickness of 1 mm was obtained using the experimental scale apparatus in the subsequent processes (Table 6, process P). Also about this, the characteristic was evaluated in each site | part of the board about 10 m in length.

  Tables 7 and 8 show the evaluation results of conductivity and strength. When the alloy composition is stipulated in the present invention, even when a 250 mm or 400 mm thick ingot, which is a mass production scale, is used, a material having stable and excellent conductivity, that is, thermal conductivity and strength, regardless of the material portion, It has become. For mass-scale materials, the material size is large, so the ingot structure and the thermal history and processing experienced during processes such as hot rolling differ significantly depending on the site, resulting in differences in the state of solid solution and precipitation of additive elements. Differences in characteristics between parts are likely to occur. The composition of the present invention succeeds in suppressing the difference in the precipitation state between the parts. By setting the Si / Mg ratio within the provisions of the present invention to a Si / Mg ratio of 1.3 or more, Mg precipitation occurs without delay, and the difference in the site characteristics of mass-produced materials is effectively suppressed.

  In the comparative alloy 40 in which the alloy composition deviates from the provisions of the present invention and the Mg content is high and the Si / Mg ratio is low, there is a difference in conductivity or strength depending on the part in the material when the mass production scale process O is performed. In particular, there are sites where the electrical conductivity does not reach 57.5%.

  In addition, the alloy 41-O in which the amounts of Si and Mg exceed the provisions of the present invention has a low electrical conductivity as a whole, and has a large difference between characteristics.

  It should be noted that, in the process P based on an ingot of a small experimental scale, the conductivity and strength are stable even in the alloy 40 that deviates from the present invention, like the alloy 38 within the scope of the present invention. From this, it is understood that the characteristic difference between the parts of the material becomes a problem particularly when a mass production process is used. Since the technology prior to the present invention is not aware of this problem, it naturally does not include a solution.

  While the present invention has been described in detail based on the above specific examples, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

  The Al—Mg—Si based alloy rolled plate excellent in thermal conductivity, strength and formability obtained in the present invention is not limited to use in a specific application, but is a video electronic component such as a plasma display, It is suitable for the use of electronic parts such as a personal computer, and has a remarkable industrial effect.

Claims (2)

In an Al-Mg-Si alloy rolled sheet, Mg is 0.1 to 0.34% by mass (hereinafter referred to as%), Si is 0.2 to 0.8%, and Cu is 0.22 to 1.0. %, The balance is made of Al and inevitable impurities, the Si / Mg content ratio is 1.3 or more, it has a fiber structure, the conductivity is 57.5% IACS or more, and the tensile strength is 180 N / mm ^2. An Al—Mg—Si alloy rolled sheet excellent in thermal conductivity, strength, and formability, characterized by the above. A method for producing an Al-Mg-Si alloy rolled sheet having the component according to claim 1,
0.1 to 0.34% by mass of Mg (hereinafter referred to as%), 0.2 to 0.8% of Si, 0.22 to 1.0% of Cu, the balance being Al and inevitable impurities An Al—Mg—Si based alloy 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, and subjected to preheating at a temperature of 400 to 540 ° C. A method for producing an Al-Mg-Si alloy rolled sheet, characterized by performing hot rolling and cold rolling at a reduction rate of 50 to 85%, followed by annealing at a temperature of 140 to 280 ° C.