JP6718275B2 - Method for manufacturing Al-Mg-Si alloy plate - Google Patents

Description

The present invention relates to a method for producing an Al—Mg—Si alloy sheet, and particularly to a method for producing an Al—Mg—Si alloy sheet having excellent thermal conductivity, conductivity, strength and workability.

Heat generators such as flat panel TVs, flat panel monitors for personal computers, laptops, tablet computers, car navigation systems, portable navigation systems, chassis of products such as mobile terminals such as smartphones and mobile phones, metal base printed circuit boards, and internal covers. The member material to be built-in or mounted is required to have excellent heat conductivity, strength and workability for prompt heat dissipation.

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

On the other hand, Al-Mg-Si alloys (6000 alloys) have good thermal conductivity and conductivity and can be strengthened by age hardening. Therefore, Al-Mg-Si alloys are used to improve strength and heat resistance. A method for obtaining an aluminum alloy plate having excellent conductivity and workability has been studied.

For example, in patent document 1, 0.1-0.34 mass% of Mg, 0.2-0.8 mass% of Si, 0.22-1.0 mass% of Cu are contained, and the balance contains Al and An Al-Mg-Si based alloy, which consists of unavoidable impurities and has a Si/Mg content ratio of 1.3 or more, is semi-continuously cast into an ingot having a thickness of 250 mm or more, and preheated at a temperature of 400 to 540°C. After that, hot rolling, cold rolling at a rolling reduction of 50 to 85%, and then annealing at a temperature of 140 to 280° C. are performed, which is a method for producing an Al—Mg—Si alloy rolled sheet. It is disclosed.

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

Patent Document 3 contains Si: 0.2 to 0.8% by mass, Mg: 0.3 to 1% by mass, Fe: 0.5% by mass or less, Cu: 0.5% by mass or less, and Ti: 0.1% by mass or less or B: 0.1% by mass or less, and at least one of Al and unavoidable impurities, or Mn and Cr as impurities are Mn: 0.1% by mass. %, Cr: Al-Mg-Si alloy ingot regulated to 0.1% by mass or less is hot rolled, and further includes a step of cold rolling. It shows a method for producing an Al-Mg-Si alloy plate, which is characterized by performing heat treatment by holding at 200 to 400°C for 1 hour or more after hot rolling and before completion of cold rolling.

As described in Patent Document 3, in the JIS 1000 to 7000 series aluminum alloys, the thermal conductivity and the electrical conductivity show a good correlation, and an aluminum alloy plate having excellent thermal conductivity has an excellent electrical conductivity. And can be used as a conductive member material as well as a heat dissipation member material.

JP, 2012-62517, A JP, 2007-9262, A JP, 2003-321755, A

As described above, the Al-Mg-Si alloy plate has been improved, but with the high performance, miniaturization, and thinning of products using aluminum alloy member materials, in addition to high conductivity and workability, more than before. While it is required for the Al—Mg—Si alloy plate to have higher strength, the methods described in Patent Document 1, Patent Document 2 and Patent Document 3 described above maintain high conductivity and workability. It was difficult to obtain the required strength.

The present invention has been made in view of the above technical background, and an object of the present invention is to provide a method for producing an Al-Mg-Si alloy plate having high electrical conductivity and good workability, and further having high strength.

The above problem can be solved by the following means.
(1) A method for manufacturing an Al-Mg-Si alloy sheet, which comprises sequentially performing hot rolling and cold rolling on an Al-Mg-Si alloy ingot, which is cold rolling after completion of hot rolling. A method for producing an Al-Mg-Si alloy plate, which comprises heat treatment at a temperature of 120°C or higher and lower than 200°C before the end.
(2) The chemical composition of the Al-Mg-Si alloy ingot is Si: 0.2 to 0.8 mass%, Mg: 0.3 to 1 mass%, Fe: 0.5 mass% or less, and Cu: The method for producing an Al-Mg-Si alloy plate according to item 1 above, which contains 0.5% by mass or less and the balance is Al and unavoidable impurities.
(3) The method for producing an Al-Mg-Si alloy plate according to item 2, wherein Mn, Cr, Zn, and Ti as impurities are each regulated to 0.1% by mass or less.
(4) The method for producing an Al-Mg-Si alloy plate according to any one of the above items 1 to 3, wherein the heat treatment is performed after the hot rolling is finished and before the cold rolling is started.
(5) The method for producing an Al-Mg-Si alloy plate according to any one of the preceding items 1 to 4, wherein the heat treatment temperature is 130°C or higher and 180°C or lower.
(6) The method for producing an Al-Mg-Si alloy sheet according to any one of the preceding items 1 to 5, wherein the rolling ratio of cold rolling after the heat treatment is 20% or more.
(7) The method for producing an Al-Mg-Si alloy plate according to any one of the items 1 to 6, wherein final annealing is performed after cold rolling.
(8) The method for producing an Al-Mg-Si alloy plate as described in 7 above, wherein the final annealing temperature is 180°C or lower.

According to the invention described in the above item (1), there is provided a method for manufacturing an Al-Mg-Si alloy plate, which comprises sequentially performing hot rolling and cold rolling on an Al-Mg-Si alloy ingot, which is hot. Since the heat treatment is performed at a temperature of 120°C or higher and lower than 200°C after the end of cold rolling and before the end of cold rolling, it is possible to improve the age hardening and conductivity during the heat treatment, and the work hardening and workability by cold rolling to improve the tensile strength. It is possible to manufacture an Al-Mg-Si alloy plate having high strength and high conductivity and good workability.

According to the invention described in the above item (2), the chemical composition of the Al—Mg—Si alloy ingot is Si: 0.2 to 0.8 mass %, Mg: 0.3 to 1 mass %, Fe: Al-Mg containing 0.5% by mass or less and Cu: 0.5% by mass or less, and hot-rolling and cold-rolling sequentially performed on an Al-Mg-Si alloy ingot containing the balance Al and unavoidable impurities. A method for manufacturing a Si-based alloy sheet, wherein heat treatment is performed at a temperature of 120° C. or higher and lower than 200° C. after completion of hot rolling and before completion of cold rolling. Further, by work hardening and workability improvement by cold rolling, it is possible to manufacture an Al-Mg-Si alloy plate exhibiting high tensile strength and conductivity and good workability.

According to the invention described in the above item (3), since Mn, Cr, Zn, and Ti as impurities are regulated to 0.1% by mass or less, respectively, the tensile strength and the conductivity show high values. It is possible to manufacture an Al-Mg-Si based alloy plate having good workability.

According to the invention described in the above item (4), since the heat treatment is performed after the hot rolling is finished and before the cold rolling is started, the age hardening and the electric conductivity are improved during the heat treatment, and the work hardening is performed by the cold rolling. By improving the workability, it is possible to manufacture an Al-Mg-Si alloy plate having high tensile strength and high electrical conductivity and good workability.

According to the invention described in the above item (5), since the heat treatment temperature is 130° C. or higher and 180° C. or lower, the effects of age hardening and improvement of conductivity can be reliably obtained.

According to the invention described in the above item (6), since the rolling ratio of the cold rolling after the heat treatment is 20% or more, the strength of the Al-Mg-Si alloy plate is improved by the cold rolling and good working is performed. You can get sex.

According to the invention described in the above item (7), since the final annealing is performed after cold rolling, the workability of the Al-Mg-Si alloy sheet is improved.

According to the invention described in the above item (8), since the temperature of the final annealing is 180° C. or less, an Al—Mg—Si alloy plate having a high tensile strength and a high electrical conductivity and good workability is manufactured. can do.

The inventor of the present application performs a heat treatment as an aging treatment after the end of hot rolling and before the end of cold rolling in a method for manufacturing an Al-Mg-Si alloy plate in which hot rolling and cold rolling are sequentially performed. As a result, they have found that an Al-Mg-Si based alloy plate having high electrical conductivity and good workability and further high strength can be obtained, and the invention of the present application has been achieved.

Below, the manufacturing method of the Al-Mg-Si type|system|group alloy plate of this application is demonstrated in detail.

In the Al-Mg-Si based alloy composition of the present application, the purpose of addition of each element and the preferable content are shown.

Mg and Si are elements necessary for developing strength, and the respective contents are Si: 0.2 mass% or more and 0.8 mass% or less, and Mg: 0.3 mass% or more and 1 mass% or less. preferable. If the Si content is less than 0.2 mass% or the Mg content is less than 0.3 mass%, the strength becomes low. On the other hand, when the Si content exceeds 0.8 mass% and the Mg content exceeds 1 mass %, the rolling load in the hot rolling increases, the productivity decreases, and the formability of the obtained aluminum alloy sheet also increases. Deteriorate. The Si content is more preferably 0.2 mass% or more and 0.6 mass% or less, and particularly preferably 0.32 mass% or more and 0.60 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 necessary components 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 mass% or less. The Fe content is more preferably regulated to 0.35% by mass or less, and particularly preferably 0.1% by mass or more and 0.25% by mass or less. The Cu content is more preferably 0.1% by mass or less.

Further, although various impurity elements are unavoidably contained in the alloy element, Mn and Cr reduce conductivity and conductivity, and Zn is less contained because the alloy content decreases in corrosion resistance as the content increases. preferable. Ti has the effect of refining the crystal grains and preventing solidification cracking when the alloy is cast into a slab, but when contained in a large amount, many crystallized substances with large size are produced, so Processability, thermal conductivity, and electrical conductivity are reduced. The content of each of Mn, Cr, Zn and Ti as impurities is preferably 0.1% by mass or less, more preferably 0.05% by mass or less.

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

Next, the processing steps for obtaining the Al—Mg—Si alloy material specified in the present application will be described.
The melting components are adjusted by a conventional method to obtain an Al-Mg-Si alloy ingot. It is preferable that the obtained alloy ingot is subjected to a homogenizing treatment as a step prior to the heating before hot rolling.

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

The pre-hot-rolling heating is carried out in order to form a uniform structure by solidifying the crystallized substances and Mg and Si in the Al-Mg-Si alloy ingot, but if the temperature is too high, a part of It is preferable to carry out at 450° C. or higher and 580° C. or lower, and particularly preferably 500° C. or higher and 580° C. or lower, as there is a possibility that specific melting will occur.

After performing homogenization treatment on the Al-Mg-Si alloy ingot, cooling may be performed before hot rolling, or homogenization treatment and heating before hot rolling may be performed continuously, The homogenization treatment and the pre-hot rolling heating may be performed at the same temperature in the preferable temperature range of the homogenization treatment and the hot rolling pre-heating.

After casting, before hot rolling and before heating, it is preferable to chamfer the ingot to remove the impurity layer near the surface of the ingot. The surface cutting may be performed after casting and before homogenization treatment, or after homogenization treatment and before heating before hot rolling.

In the present application, the surface temperature of the Al—Mg—Si alloy plate immediately after the hot rolling is preferably 170° C. or lower. By setting the temperature of the alloy sheet immediately after the hot rolling to 170° C. or lower, the quenching effect is enhanced, and the subsequent heat treatment causes age hardening and electrical conductivity improvement.

If the surface temperature of the Al-Mg-Si alloy plate immediately after hot rolling is too high, the effect of quenching will be insufficient, and the strength will be improved even if heat treatment is performed after completion of hot rolling and before completion of cold rolling. It will be difficult. The surface temperature of the aluminum plate immediately after the completion of hot rolling is preferably 150°C or lower, and particularly preferably 130°C or lower.

After completion of hot rolling and before completion of cold rolling, the Al—Mg—Si alloy plate is heat-treated to age-harden and improve conductivity.

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

The time for heat treatment of the Al-Mg-Si alloy plate to be carried out at a temperature of 120°C or higher and lower than 200°C after the end of hot rolling and before the end of cold rolling is not particularly limited, but the effects of age hardening and conductivity improvement are obtained. The time may be adjusted at a predetermined temperature so as to obtain the heat treatment, and for example, the heat treatment may be performed by adjusting the time in the range of 1 to 12 hours.

After the heat treatment, cold rolling is performed to work-harden and further improve the strength.

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

After the heat treatment, cold rolling is performed to obtain an Al-Mg-Si alloy plate having a predetermined thickness. Cold rolling after heat treatment is preferably carried out at a rolling rate of 20% or more in order to improve strength and workability. The rolling rate of the Al—Mg—Si alloy plate by cold rolling after the heat treatment is more preferably 30% or more, and particularly preferably 60% or more.

The Al—Mg—Si alloy plate after cold rolling may be washed as necessary.

When the workability of the Al-Mg-Si alloy plate is further emphasized, final annealing may be performed after cold rolling. The final annealing is preferably performed at 180° C. or less, more preferably 160° C. or less, and particularly preferably 140° C. or less so that the strength of the Al—Mg—Si alloy plate does not become too low.

The time for the final annealing of the Al-Mg-Si alloy plate to be carried out at a temperature of 180°C or lower may be adjusted so that the required workability and strength can be obtained. For example, the final annealing is performed in the range of 1 to 10 hours. It may be selected according to the temperature.

The Al—Mg—Si alloy plate of the present invention may be manufactured using a coil or a single plate. Further, the alloy sheet may be cut in any step after the cold rolling and the step after cutting may be performed as a single sheet, or slits may be formed depending on the application.

Examples and comparative examples of the present invention will be 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 alloy slab after chamfering was homogenized at 570° C. for 4 hours in a heating furnace, and then heated at 540° C. for 4 hours at 540° C. for 4 hours in the same furnace. After heating before hot rolling, the slab at 540° C. was taken out of the heating furnace, and rough hot rolling was performed to obtain an alloy plate having a thickness of 7.0 mm. The temperature of the alloy sheet immediately after the hot rolling was 110°C. The alloy plate after hot rolling was heat-treated at 170° C. for 5 hours, and then cold rolled at a rolling ratio of 98% to obtain an aluminum alloy plate having a product plate thickness of 0.15 mm.

[Examples 2-39, Comparative Examples 1-6]
After the aluminum alloy slabs shown in Table 1 were chamfered, they were treated under the conditions shown in Tables 2 to 6 to obtain aluminum alloy plates. As in Example 1, the homogenization treatment and the heating before hot rolling were continuously performed in the same furnace in all Examples and Comparative Examples. Further, in some examples, final annealing was performed after cold rolling.

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

The tensile strength of JIS No. 5 test piece was measured at room temperature by a conventional method.

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

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

Tables 2 to 7 show the evaluation results of tensile strength, conductivity, and workability.

In the examples in which the heat treatment temperature after the hot rolling and before the cold rolling is in the range of 120° C. or higher and lower than 200° C., the tensile strength and the conductivity are high and the workability is good. In Comparative Example 1 in which the heat treatment temperature after the hot rolling and before the cold rolling is less than the lower limit of the specified range of the present application, the tensile strength and the electrical conductivity are inferior to those of the examples, and after the hot rolling and before the cold rolling is finished. In Comparative Example 2 in which the heat treatment temperature exceeds the upper limit of the specified range of the present application, the tensile strength is inferior to that of the example. Further, Comparative Example 3 having a lower Si content than that of the Examples, Comparative Example 4 having a higher Si content than the Examples, Comparative Example 5 having a lower Mg content than the Examples, and Comparative Example 6 having a higher Mg content than the Examples. Also, at least one of the tensile strength and the conductivity is inferior to the examples, and the comparative examples 4 and 6 are also inferior in workability.

Claims (6)

The chemical composition contains Si: 0.2 to 0.8% by mass, Mg: 0.3 to 1% by mass, Fe: 0.5% by mass or less and Cu: 0.5% by mass or less. Al in which Mn, Cr, Zn, and Ti are regulated to 0.1% by mass or less, respectively, and hot-rolling and cold-rolling are sequentially performed on an Al-Mg-Si alloy ingot containing the balance Al and inevitable impurities. A method for manufacturing an Mg-Si alloy plate, wherein the surface temperature of the alloy plate immediately after the hot rolling is 170° C. or lower, after the hot rolling is completed, and before the cold rolling is completed without performing the solution treatment. A method for producing an Al-Mg-Si alloy plate, which further comprises heat treatment at a temperature of 120°C or more and less than 200°C. The method for producing an Al-Mg-Si alloy sheet according to claim 1, wherein the heat treatment is performed after the hot rolling is finished and before the cold rolling is started. The method for producing an Al-Mg-Si alloy plate according to claim 1 or 2, wherein the heat treatment temperature is 130°C or higher and 180°C or lower. The method for producing an Al-Mg-Si alloy sheet according to any one of claims 1 to 3 , wherein a rolling ratio of cold rolling after the heat treatment is 20% or more. Al-Mg-Si-based method for producing alloy sheet according to any one of claims 1 to 4 implementing the final annealing after cold rolling. The method for producing an Al-Mg-Si alloy plate according to claim 5 , wherein the final annealing temperature is 180°C or lower.