JP2008255411A - Method for producing aluminum alloy thick plate, and aluminum alloy thick plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an aluminum alloy thick plate in which productivity is excellent, the controls of surface conditions and flatness are facilitated, and the accuracy of plate thickness is improved, and to provide an aluminum alloy thick plate. <P>SOLUTION: The method for producing an aluminum alloy thick plate performs: a melting stage (S1) where an aluminum alloy comprising a prescribed amount of Mg and further comprising at least one or more kinds selected from Si, Fe, Cu, Mn, Cr, Zn, Ti and Zr, and the balance Al with inevitable impurities is melted; a hydrogen gas removal stage (S2) where a hydrogen gas is removed from the melted aluminum alloy; a filtering stage (S3) where inclusions are removed from the aluminum alloy freed of the hydrogen gas; a casting stage (S4) where the aluminum alloy freed of the inclusions is cast, so as to produce a cast ingot; a slicing stage (S5) where the cast ingot is sliced into a prescribed thickness; and a heat treatment stage (S6) where the sliced aluminum alloy thick plate is heat-treated in this order. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an aluminum alloy thick plate and an aluminum alloy thick plate.

In general, aluminum alloy materials such as aluminum alloy thick plates are used in various applications such as base electronics, transfer equipment, semiconductor equipment such as chambers for vacuum equipment, as well as electrical and electronic parts, manufacturing equipment, daily necessities, and machine parts. Has been.
Such an aluminum alloy material is manufactured by melting and casting an aluminum alloy as a raw material to produce an ingot, homogenizing heat treatment as necessary, and then rolling the ingot to a predetermined thickness. It is general (see, for example, Patent Document 1).

In addition, as a die material used for a press die, steel, cast steel or the like is used for mass production, and a zinc alloy cast material, an aluminum alloy cast material or the like is used for trial production. Further, in recent years, due to the tendency to reduce the variety of products, rolling materials such as rolled aluminum alloys or forged materials have become widespread for medium and small volume production.
JP 2005-344173 A (paragraphs 0037 to 0045)

However, the above-described method for producing an aluminum alloy material by rolling has the following problems.
In the method of rolling after casting, the surface state and flatness of the rolled plate (particularly the flatness in the longitudinal direction) are controlled only by the rolling roll, and a thick oxide film is formed on the rolled plate surface by hot rolling. Due to the formation, there is a problem that it is difficult to control the surface state and the flatness. In addition, with a rolling roll, it is difficult to control the plate thickness, so it is difficult to improve the plate thickness accuracy, and the size of the intermetallic compound is increased at the center in the plate thickness direction. There was a problem that unevenness occurred on the surface in the cross section in the thickness direction. Furthermore, in the case of rolling an ingot, there is a problem in that costs increase due to an increase in work steps due to an increase in the number of rolling operations.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has excellent productivity, easy control of the surface state and flatness, and a method for manufacturing an aluminum alloy thick plate with improved plate thickness accuracy. It aims at providing the obtained aluminum alloy thick plate.

  In order to solve the above-mentioned problem, the method for producing an aluminum alloy thick plate according to claim 1 includes Mg: 1.5% by mass or more and 12.0% by mass or less, and Si: 0.7% by mass or less. Fe: 0.8 mass% or less, Cu: 0.6 mass% or less, Mn: 1.0 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 A melting step of melting an aluminum alloy containing at least one of mass% or less, Zr: 0.3 mass% or less, and the balance being Al and inevitable impurities, and aluminum dissolved in the melting step Casting a dehydrogenation gas step for removing hydrogen gas from the alloy, a filtration step for removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step, and an aluminum alloy from which inclusions have been removed in the filtration step. Make ingots A casting process, a slicing process for slicing the ingot to a predetermined thickness, and holding an aluminum alloy thick plate of a predetermined thickness sliced in the slicing process at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer. A heat treatment step for heat treatment is performed in this order.

  The manufacturing method of the aluminum alloy thick plate which concerns on Claim 2 contains Mn: 0.3 mass% or more and 1.6 mass% or less, Furthermore, Si: 0.7 mass% or less, Fe: 0.8 mass% Hereafter, Cu: 0.5 mass% or less, Mg: 1.5 mass% or less, Cr: 0.3 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, Zr: 0 A melting step of dissolving an aluminum alloy containing at least one of 3 mass% or less and the balance being Al and inevitable impurities, and removing hydrogen gas from the aluminum alloy dissolved in the melting step Casting for producing an ingot by casting a dehydrogenation gas step, a filtration step for removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step, and an aluminum alloy from which inclusions have been removed in the filtration step Process and the ingot A slicing step of slicing to a predetermined thickness, and a heat treatment step of heat-treating the aluminum alloy thick plate of the predetermined thickness sliced in the slicing step at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer in this order. It is characterized by performing.

  The method for producing an aluminum alloy thick plate according to claim 3 includes Si: 0.2% by mass to 1.6% by mass, Mg: 0.3% by mass to 1.5% by mass, and further Fe : 0.8 mass% or less, Cu: 1.0 mass% or less, Mn: 0.6 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% % Or less, Zr: at least one of 0.3% by mass or less, and a melting step of melting an aluminum alloy consisting of Al and inevitable impurities, and the aluminum alloy dissolved in the melting step Casting a dehydrogenation gas step for removing hydrogen gas from a casting step, a filtration step for removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step, and an aluminum alloy from which inclusions have been removed in the filtration step. Casting to make ingots The slicing step of slicing the ingot to a predetermined thickness, and the aluminum alloy thick plate of the predetermined thickness sliced in the slicing step is held at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer and heat-treated. The heat treatment step is performed in this order.

  The method for producing an aluminum alloy thick plate according to claim 4 includes Mg: 0.4 mass% to 4.0 mass%, Zn: 3.0 mass% to 9.0 mass%, and further Si : 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 3.0 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti: 0.1 mass% % Or less, Zr: at least one of 0.25% by mass or less, and a melting step of melting an aluminum alloy consisting of Al and inevitable impurities, and the aluminum alloy dissolved in the melting step Casting a dehydrogenation gas step for removing hydrogen gas from a casting step, a filtration step for removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step, and an aluminum alloy from which inclusions have been removed in the filtration step. Casting to produce ingots A step of slicing the ingot to a predetermined thickness, and heat-treating the aluminum alloy thick plate sliced in the slicing step at a temperature of 200 ° C. or higher and lower than 350 ° C. for 1 hour or longer. The heat treatment step is performed in this order.

  According to such a manufacturing method, the fineness and strength of the intermetallic compound of the aluminum alloy thick plate are improved by limiting the content of the predetermined element of the aluminum alloy thick plate to a predetermined range. Also, by removing the hydrogen gas through the dehydrogenation process, the hydrogen concentration in the ingot is limited, and even if the crystal grains in the ingot become coarse, hydrogen accumulates at the grain boundary near the surface of the ingot. It is not concentrated, and the swelling of the ingot and the swelling of the aluminum alloy thick plate caused by the swelling are suppressed, and the potential defect on the thick plate surface that appears as the surface defect of the thick plate is suppressed. Furthermore, the strength of the aluminum alloy thick plate is improved. Further, inclusions such as oxides and non-metals are removed from the aluminum alloy by the filtration step. By slicing the ingot in the slicing step, the oxide film thickness is reduced, the surface state, flatness and plate thickness accuracy of the aluminum alloy thick plate are improved, and the productivity is improved. Furthermore, by performing a heat treatment in the heat treatment step, the internal stress of the aluminum alloy thick plate is removed, and the internal structure becomes uniform.

  The method for producing an aluminum alloy thick plate according to claim 5 is characterized in that a surface smoothing treatment is further performed on the surface of the heat-treated aluminum alloy thick plate after the heat treatment step.

  According to such a manufacturing method, the surface state and flatness of the aluminum alloy thick plate are further improved. In addition, the smoothing of the surface eliminates gas accumulation on the thick plate surface.

  The method for producing an aluminum alloy thick plate according to claim 6 is characterized in that the surface smoothing treatment is performed by one or more methods selected from a cutting method, a grinding method and a polishing method.

  According to such a manufacturing method, the surface state and flatness of the aluminum alloy thick plate are further improved. Moreover, the smoothing of the thick plate surface eliminates gas accumulation.

  In the method for producing an aluminum alloy thick plate according to claim 7, in the slicing step, when the thickness of the ingot is T, the thickness direction is centered from the central portion in the thickness direction to the respective surfaces in the thickness direction. A total thickness of T / 30 to T / 5 is removed.

  According to such a manufacturing method, the central portion of the ingot that is likely to have unevenness on the surface and cross section of the thick plate after the anodized treatment is removed, and a thick plate excellent in appearance after the anodized treatment can be obtained. , Less variation in the lot.

  An aluminum alloy thick plate according to an eighth aspect is an aluminum alloy thick plate produced by the above-described method for producing an aluminum alloy thick plate, wherein an average crystal grain size is 400 μm or less.

  According to such an aluminum alloy thick plate, the surface state, flatness, and plate thickness accuracy of the aluminum alloy thick plate are improved, and gas accumulation is eliminated by smoothing the surface of the thick plate. Furthermore, since the size of the intermetallic compound in the aluminum alloy thick plate is small, unevenness in the cross section of the thick plate after the alumite treatment is less likely to occur.

  According to the aluminum alloy thick plate manufacturing method according to claims 1 to 4 of the present invention, the strength of the aluminum alloy thick plate is improved. In addition, since the aluminum alloy is manufactured by slicing the ingot, it is not necessary to reduce the thickness by hot rolling like conventional aluminum alloys, and the work process can be omitted and the productivity can be improved. Can be made. Further, unevenness of the surface in the cross section of the thick plate can be eliminated, the flatness and appearance appearance after the alumite treatment can be improved, and the plate thickness accuracy can also be improved. Furthermore, the balance of flatness, strength and machinability of the aluminum alloy thick plate is improved. That is, if the sliced aluminum alloy thick plate is heat-treated at a temperature of 400 ° C. or higher, the flatness is improved, but the strength is lowered and the machinability (chip cutting property) is also lowered. To do. On the other hand, the aluminum alloy thick plate can be prevented from increasing ductility by performing a heat treatment at a temperature of 200 ° C. or higher and lower than 400 ° C. (in claim 4, 200 ° C. or higher and lower than 350 ° C.). The internal stress of the aluminum alloy thick plate can be removed and the internal structure can be made uniform without lowering the chip separation property, and the flatness and thickness accuracy can be improved while maintaining the strength. Can be made.

  According to the method for producing an aluminum alloy thick plate according to claims 5 and 6, since the surface smoothing treatment is performed on the surface of the heat-treated aluminum alloy thick plate, the surface condition and flatness of the aluminum alloy thick plate are further increased. Can be improved. Further, since the gas is not accumulated due to the smoothing of the surface, the degree of vacuum of the chamber can be improved when used in a vacuum apparatus chamber.

  According to the method for producing an aluminum alloy thick plate according to claim 7, the central portion of the ingot that is likely to have unevenness on the surface and cross section of the thick plate after the alumite treatment is removed, so that the appearance after the alumite treatment is excellent. Thick plates can be obtained. In addition, variations in lots can be reduced.

  According to the aluminum alloy thick plate according to claim 8, the surface state, flatness, and plate thickness accuracy of the aluminum alloy thick plate are good, and gas accumulation is eliminated by smoothing the surface. It can be a thick plate. Furthermore, the surface appearance after the alumite treatment is less likely to be uneven. Therefore, it can be used for a wide variety of applications, and can be recycled to other applications.

  Next, with reference to drawings, the manufacturing method of the aluminum alloy thick plate and aluminum alloy thick plate which concern on this invention are demonstrated in detail. In the drawings to be referred to, FIG. 1 is a diagram showing a flow of a manufacturing method of an aluminum alloy thick plate, and FIG. 2 is a schematic diagram showing a central portion of an ingot to be removed in a slicing step.

≪Method for manufacturing aluminum alloy thick plate≫
As shown in FIG. 1, the manufacturing method of an aluminum alloy thick plate (hereinafter referred to as “thick plate” as appropriate) includes a melting step (S1) for dissolving the aluminum alloy, a dehydrogenation gas step (S2), and a filtration step ( S3), a casting process (S4), a slicing process (S5), and a heat treatment process (S6) are performed in this order. Moreover, you may include a surface smoothing process process (S7) after a heat processing process (S6) as needed.

  In this manufacturing method, first, an aluminum alloy as a raw material is melted by the melting step (S1). In the aluminum alloy dissolved in the melting step (S1), hydrogen gas is removed in the dehydrogenation gas step (S2), and inclusions such as oxides and nonmetals are removed in the filtration step (S3). Next, the aluminum alloy is cast into an ingot in the casting step (S4), and the ingot is sliced to a predetermined thickness in the slicing step (S5). Thereafter, the sliced aluminum alloy thick plate having a predetermined thickness is heat-treated in the heat treatment step (S6), and further, if necessary, the surface smoothing treatment step (S7) is followed by the surface smoothing treatment step (S7). Smoothed.

Next, each process in the manufacturing method of an aluminum alloy thick plate is demonstrated.
<Dissolution process>
The melting step (S1) is a step of melting a 5000 Al-Mg alloy. Aluminum alloys include 5000 series Al-Mg series alloys, 3000 series Al-Mn series alloys, 6000 series Al-Mg-Si series alloys, and 7000 series Al-Zn-Mg series alloys. Also good.

(Al-Mg alloy)
The Al—Mg-based alloy used in the present invention contains Mg: 1.5 mass% or more and 12.0 mass% or less, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu : 0.6 mass% or less, Mn: 1.0 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, Zr: 0.3 mass% % Is an aluminum alloy containing at least one or more of% and the balance of Al and inevitable impurities.
The reason why the content of each component is limited to the numerical values will be described below.

[Mg: 1.5% by mass or more and 12.0% by mass or less]
Mg has the effect of improving the strength of the aluminum alloy. If the Mg content is less than 1.5% by mass, this effect is small. On the other hand, if the Mg content exceeds 12.0% by mass, the castability is remarkably deteriorated and product production becomes impossible. Therefore, the content of Mg is set to 1.5% by mass or more and 12.0% by mass or less.

The aluminum alloy contains Mg as an essential component, and further contains at least one of the following Si, Fe, Cu, Mn, Cr, Zn, Ti, and Zr.
[Si: 0.7% by mass or less]
Si has the effect of improving the strength of the aluminum alloy. Si is usually mixed into the aluminum alloy as a metal impurity, and in the casting step (S4) and the like, the Al- (Fe)-(Mn) -Si based metal is combined with Mn and Fe in the ingot. To give a compound. When the Si content exceeds 0.7% by mass, a coarse intermetallic compound is generated in the ingot, and unevenness of the surface appearance after the alumite treatment tends to occur. Therefore, the Si content is 0.7% by mass or less.

[Fe: 0.8% by mass or less]
Fe has the effect of refining and stabilizing the crystal grains of the aluminum alloy and improving the strength. Fe is usually mixed into the aluminum alloy as a metal base impurity, and an Al—Fe— (Mn) — (Si) intermetallic compound is formed in the ingot in combination with Mn and Si in the casting step (S4) and the like. Let When the Fe content exceeds 0.8% by mass, a coarse intermetallic compound is generated in the ingot, and unevenness of the surface appearance after the alumite treatment tends to occur. Therefore, the Fe content is set to 0.8 mass% or less.

[Cu: 0.6% by mass or less]
Cu has the effect of improving the strength of the aluminum alloy. However, a content of Cu of 0.6% by mass is sufficient to ensure strength that can withstand use as a thick plate. Therefore, the Cu content is 0.6% by mass or less.

[Mn: 1.0% by mass or less]
Mn has the effect of improving the strength by dissolving in an aluminum alloy. When the content of Mn exceeds 1.0% by mass, a coarse intermetallic compound is generated, and unevenness of the surface appearance after the alumite treatment tends to occur. Therefore, Mn content shall be 1.0 mass% or less.

[Cr: 0.5% by mass or less]
Cr is precipitated as a fine compound in the casting step (S4) and the heat treatment step (S6), and has the effect of suppressing crystal grain growth. If the Cr content exceeds 0.5% by mass, coarse Al—Cr intermetallic compounds as primary crystals are formed, and unevenness in the surface appearance after anodizing is likely to occur. Therefore, the Cr content is 0.5% by mass or less.

[Zn: 0.4 mass% or less]
Zn has the effect of improving the strength of the aluminum alloy. However, a content of Zn of 0.4% by mass is sufficient to ensure a strength that can be used as a thick plate. Therefore, the Zn content is set to 0.4 mass% or less.

[Ti: 0.1% by mass or less]
Ti has the effect of refining the crystal grains of the ingot. Even if the Ti content exceeds 0.1% by mass, the effect is saturated. Therefore, the Ti content is 0.1% by mass or less.

[Zr: 0.3 mass% or less]
Zr has the effect of refining the crystal grains of the ingot. The effect is saturated even if the content of Zr exceeds 0.3% by mass. Therefore, the Zr content is 0.3% by mass or less.

[Balance: Al and inevitable impurities]
In addition to the above components, the aluminum alloy is composed of Al and inevitable impurities. In addition, it is considered that unavoidable impurities include, for example, V, B, etc., but if these contents are 0.01% by mass or less, respectively, the characteristics of the aluminum alloy thick plate of the present invention are affected. do not do.

(Al-Mn alloy)
The Al—Mn alloy used in the present invention contains Mn: 0.3% by mass to 1.6% by mass, Si: 0.7% by mass or less, Fe: 0.8% by mass or less, Cu : 0.5 mass% or less, Mg: 1.5 mass% or less, Cr: 0.3 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, Zr: 0.3 mass% % Is an aluminum alloy containing at least one or more of% and the balance of Al and inevitable impurities.
The reason why the content of each component is limited to the numerical values will be described below.
The reason for limiting Si, Fe, Cu, Cr, Zn, Ti, and Zr and unavoidable impurities are the same as those of the Al—Mg alloy, and thus the description thereof is omitted here.

[Mn: 0.3 mass% or more and 1.6 mass% or less]
Mn has the effect of improving the strength by dissolving in an aluminum alloy. If the Mn content is less than 0.3% by mass, this effect is small. On the other hand, if the Mn content exceeds 1.6% by mass, a coarse intermetallic compound is formed, and the surface appearance after anodizing is uneven. Is likely to occur. Therefore, Mn content shall be 0.3 mass% or more and 1.6 mass% or less.

  The aluminum alloy contains Mn as an essential component, and further contains at least one of Si, Fe, Cu, Mg, Cr, Zn, Ti, and Zr.

[Mg: 1.5% by mass or less]
Mg has the effect of improving the strength of the aluminum alloy. However, a content of Mg of 1.5% by mass is sufficient to ensure a strength that can be used as a thick plate. Therefore, the Mg content is 1.5% by mass or less.

(Al-Mg-Si alloy)
The Al—Mg—Si based alloy used in the present invention contains Si: 0.2 mass% to 1.6 mass%, Mg: 0.3 mass% to 1.5 mass%, and further Fe: 0.8 mass% or less, Cu: 1.0 mass% or less, Mn: 0.6 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% Hereinafter, it is an aluminum alloy containing at least one of Zr: 0.3% by mass or less, and the balance being Al and inevitable impurities.
The reason why the content of each component is limited to the numerical values will be described below.
The reason for limiting Fe, Mn, Cr, Ti, and Zr and unavoidable impurities are the same as those of the Al—Mg alloy, and thus the description thereof is omitted here.

[Si: 0.2% by mass or more and 1.6% by mass or less]
Si has the effect of improving the strength of the aluminum alloy. Si is usually mixed into the aluminum alloy as a metal base impurity, and in the casting step (S4) or the like, an Al— (Fe) —Si-based and Si-based intermetallic compound is generated in the ingot. When the Si content is less than 0.2% by mass, the effect of improving the strength is small. On the other hand, when the Si content exceeds 1.6% by mass, coarse Si-based intermetallic compounds are contained in the ingot. This is likely to cause unevenness in the surface appearance after the alumite treatment. Therefore, the Si content is 0.2 mass% or more and 1.6 mass% or less.

[Mg: 0.3% to 1.5% by mass]
Mg has the effect of improving the strength of the aluminum alloy by coexisting with Si to form Mg ₂ Si. If the Mg content is less than 0.3% by mass, this effect is small. On the other hand, even if the Mg content exceeds 1.5% by mass, the effect of improving the strength is saturated. Therefore, the Mg content is set to 0.3 mass% or more and 1.5 mass% or less.

  The aluminum alloy contains Si and Mg as essential components, and further contains at least one of Fe, Cu, Mn, Cr, Zn, Ti, and Zr.

[Cu: 1.0% by mass or less]
Cu has the effect of improving the strength of the aluminum alloy. When the content of Cu exceeds 1.0% by mass, the corrosion resistance decreases. Therefore, the Cu content is 1.0% by mass or less.

[Zn: 0.4 mass% or less]
Zn has the effect of improving the strength of the aluminum alloy. When the Zn content exceeds 0.4% by mass, the corrosion resistance decreases. Therefore, the Zn content is set to 0.4 mass% or less.

(Al-Zn-Mg alloy)
The Al—Zn—Mg-based alloy used in the present invention contains Mg: 0.4 mass% to 4.0 mass%, Zn: 3.0 mass% to 9.0 mass%, and Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 3.0 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti: 0.1 mass% Hereinafter, it is an aluminum alloy containing at least one of Zr: 0.25% by mass or less, with the balance being Al and inevitable impurities.
The reason why the content of each component is limited to the numerical values will be described below.
The reason for limiting Cr, Ti, and Zr and unavoidable impurities are the same as those of the Al—Mg alloy, and thus the description thereof is omitted here.

[Mg: 0.4% by mass or more and 4.0% by mass or less]
Mg has the effect of improving the strength of the aluminum alloy. When the Mg content is less than 0.4% by mass, this effect is small. On the other hand, when the Mg content exceeds 4.0% by mass, the surface appearance after the alumite treatment tends to be uneven. Therefore, the Mg content is set to 0.4% by mass or more and 4.0% by mass or less.

[Zn: 3.0 mass% or more and 9.0 mass% or less]
Zn has the effect of improving the strength of the aluminum alloy. When the Zn content is less than 3.0% by mass, this effect is small. On the other hand, when the Zn content exceeds 9.0% by mass, the surface appearance after the alumite treatment tends to be uneven. Therefore, the Zn content is set to 3.0% by mass or more and 9.0% by mass or less.

  The aluminum alloy contains Mg and Zn as essential components, and further contains at least one of Si, Fe, Cu, Mn, Cr, Ti, and Zr.

[Si: 0.7% by mass or less]
Si is usually mixed into the aluminum alloy as a metal base impurity, and an Al— (Fe) —Si intermetallic compound is produced in the ingot in the casting step (S4) or the like. When the Si content exceeds 0.7% by mass, a coarse Al— (Fe) —Si intermetallic compound is generated in the ingot, and unevenness of the surface appearance after the alumite treatment tends to occur. Therefore, the Si content is 0.7% by mass or less.

[Fe: 0.8% by mass or less]
Fe is also usually mixed into the aluminum alloy as a metal base impurity, and an Al—Fe-based intermetallic compound is produced in the ingot in the casting step (S4) or the like. When the Fe content exceeds 0.8% by mass, a coarse Al—Fe intermetallic compound is generated in the ingot, and unevenness of the surface appearance after the alumite treatment tends to occur. Therefore, the Fe content is set to 0.8 mass% or less.

[Cu: 3.0% by mass or less]
Cu has the effect of improving the strength of the aluminum alloy. When the content of Cu exceeds 3.0% by mass, the corrosion resistance decreases. Therefore, the Cu content is 3.0% by mass or less.

[Mn: 0.8% by mass or less]
Mn has the effect of refining the crystal structure. When the content of Mn exceeds 0.8% by mass, a coarse intermetallic compound is produced, and unevenness in the surface appearance after the alumite treatment tends to occur. Therefore, Mn content shall be 0.8 mass% or less.

<Dehydrogenation gas process>
The dehydrogenation gas step (S2) is a step of removing hydrogen gas from the aluminum alloy melted in the melting step (S1).
Hydrogen gas is generated from hydrogen in fuel, water adhering to metal, etc., and other organic substances. If a large amount of hydrogen gas is contained, it may cause pinholes or weaken the product. In addition, hydrogen accumulates and concentrates at the grain boundaries near the surface of the ingot, causing bulges in the ingot and creaking of the aluminum alloy thick plate due to the bulges, and the surface of the thick plate that appears as a surface defect of the thick plate. Potential defects arise.

Therefore, the hydrogen gas is preferably 0.2 ml or less in 100 g of the aluminum alloy, and more preferably 0.1 ml or less.
The removal of hydrogen gas in the dehydrogenation step can be suitably performed by performing fluxing, chlorine refining, in-line refining or the like on the molten metal, but a sniff or porous plug (Japanese Patent Laid-Open No. 2002-146447) If it uses, it can remove more suitably.

  Here, the concentration of hydrogen gas in the ingot is, for example, a sample cut out from the ingot before slicing and subjected to ultrasonic cleaning with alcohol and acetone, for example, an inert gas flow melting thermal conductivity method (LIS). AO6-1993). The concentration of hydrogen gas in the aluminum alloy thick plate is, for example, a sample cut out from the aluminum alloy thick plate, immersed in NaOH, the surface oxide film removed with nitric acid, and ultrasonically cleaned with alcohol and acetone. , By vacuum heating extraction capacity method (LIS AO6-1993).

<Filtration process>
The filtration step (S3) is a step of mainly removing oxides and non-metallic inclusions from the aluminum alloy with a filtration device.
The filtration device is provided with a ceramic tube using alumina having a particle size of, for example, about 1 mm, and the oxides and inclusions can be removed by passing molten metal through the tube.
By these dehydrogenation gas and filtration, in the casting step (S4), an aluminum alloy with high quality can be made into an ingot. In addition, since deposition of oxide deposits (dross) can be suppressed, labor for removing dross can be reduced.

<Casting process>
The casting step (S4) is, for example, a step for producing an ingot by forming and solidifying a molten aluminum alloy into a predetermined shape such as a rectangular parallelepiped shape in a casting apparatus configured to include a water-cooled mold. It is.
As a casting method, a semi-continuous casting method can be used.
In the semi-continuous casting method, molten metal is poured from above into a metal water-cooled mold with an open bottom, and the solidified metal is continuously removed from the bottom of the water-cooled mold to obtain an ingot of a predetermined thickness. It is. The semi-continuous casting method may be performed either vertically or horizontally.

<Slicing process>
The slicing step (S5) is a step of slicing the ingot manufactured in the casting step (S4) to a predetermined thickness.
As the slicing method, a slab slicing method can be used.
The slab slicing method is a method of slicing an ingot produced by the above-described semi-continuous casting method with a band saw cutter or the like to cut the ingot in the casting direction, whereby an aluminum alloy thick plate having a predetermined thickness can be obtained. Manufactured. Here, the thickness of the aluminum alloy thick plate is preferably 15 to 200 mm, but is not particularly limited, and can be appropriately changed depending on the use of the aluminum alloy thick plate.

As a method of slicing, it is preferable to use a band saw, but it is not particularly limited, and it may be cut by a circular saw cutter. Moreover, you may cut | disconnect by a laser, water pressure, etc.
Thus, by slicing the ingot, an aluminum alloy thick plate superior in surface condition, flatness, plate thickness accuracy, etc., compared with the rolled material, for example, in the evaluation of flatness, per 1 m of casting direction It is possible to obtain a thick plate having a flatness (warping amount) of 0.4 mm or less / 1 m length and a plate thickness accuracy of ± 100 μm or less.

  Further, as shown in FIG. 2, in the slicing step (S5), when the thickness of the ingot 1 is T, the thickness is uniform from the central portion A in the thickness direction toward the respective surfaces in the thickness direction. Now, it is preferable to remove the total thickness T / 30 to T / 5 (the central portion B of the ingot 1 (the hatched portion in FIG. 2). FIG. 2 shows the thickness of about T / 5. ) Here, the upper and lower thicknesses b1 and b2 in the central portion B of the ingot 1 to be removed are the same thickness (up and down equal). However, a thickness difference of about 30% is allowed. The central portion A in the thickness direction here is a portion of about 1/2 of the thickness T of the ingot 1 in the center in the thickness direction of the ingot 1, that is, a portion of about T / 2. Say.

  The central portion B of the ingot 1 is likely to have unevenness (color tone unevenness) on the surface and cross section of the thick plate after the anodizing treatment. By removing this portion, a thick plate having excellent appearance after the anodizing treatment is obtained. In addition, it is possible to reduce the variation in the lot. If the thickness to be removed is less than T / 30, a thick plate with uneven color tone is likely to occur on the surface appearance after the alumite treatment, and variations in lots are likely to occur. On the other hand, when T / 5 is exceeded, the removal amount becomes too large, and the productivity tends to be lowered. Therefore, the removal amount of the central portion B of the ingot 1 is from the central portion A in the thickness direction toward each surface in the thickness direction, and is equal to the total thickness of T / 30 to T / 5. Is preferred.

After slicing the ingot in the slicing step (S5), in the heat treatment step (S6), heat treatment is performed for the purpose of removing internal stress and homogenizing the internal structure.
By performing the heat treatment, the flatness, the plate thickness accuracy, and the appearance properties after the alumite treatment are improved.
<Heat treatment process>
The heat treatment step (S6) is a step of heat-treating the aluminum alloy thick plate having a predetermined thickness sliced in the slicing step (S5).
In the case of the Al—Mg alloy, the Al—Mn alloy, and the Al—Mg—Si alloy, the heat treatment is performed at a treatment temperature of 200 ° C. or more and less than 400 ° C., and the Al—Zn—Mg alloy. In the case of an alloy, it is performed by holding at a treatment temperature of 200 ° C. or higher and lower than 350 ° C. for 1 hour or longer.

  As described above, since the ingot produced in the casting step (S4) is sliced, warping is likely to occur due to the release of internal residual stress, but the aluminum alloy thick plate with a predetermined thickness sliced after slicing Is placed on a surface plate or the like and heat treated to improve the flatness.

  When the treatment temperature is less than 200 ° C., the amount of internal stress removed is small, and the effect of heat treatment is small. Therefore, the processing temperature is set to 200 ° C. or higher. Further, when the treatment temperature is 400 ° C. or higher (350 ° C. or higher in the case of the Al—Zn—Mg-based alloy), ductility increases and strength and machinability decrease. In addition, the machinability here means the chip parting property. The chips are preferably finely divided, and if the chips are long, they are entangled with the processing tool (blade) and rotate together, which causes problems such as scratching the surface of the plank or damaging the tool. Accordingly, the processing temperature is set to less than 400 ° C. (in the case of the Al—Zn—Mg alloy, less than 350 ° C.). By performing the heat treatment under such a temperature condition, the flatness and the plate thickness accuracy can be improved without reducing the strength and the machinability.

  On the other hand, when the treatment time is less than 1 hour, the solid solution of the intermetallic compound is insufficient and the precipitation tends to occur. Therefore, processing time shall be 1 hour or more. Further, if the treatment time exceeds about 8 hours, the effect of the heat treatment is saturated without further improvement, resulting in energy loss. Therefore, the treatment time is preferably 8 hours or less.

The aluminum alloy thick plate heat-treated in the heat treatment step (S6) removes crystallized substances and oxides formed on the surface of the thick plate as necessary, and eliminates gas accumulation on the surface of the thick plate. Therefore, a surface smoothing process may be performed.
<Surface smoothing process>
The surface smoothing treatment step (S7) is a step of smoothing the surface of the aluminum alloy thick plate heat treated in the heat treatment step (S6).
As the surface smoothing treatment method, a cutting method such as end mill cutting or diamond bite cutting, a grinding method in which the surface is ground with a grindstone, a polishing method such as buffing, or the like can be used, but it is not limited thereto. .

Here, the vacuum apparatus chamber, which is one of the uses of the aluminum alloy thick plate, releases the adsorbed gas from the inner surface of the chamber when the pressure is reduced to a high vacuum, or the gas atoms dissolved in the thick plate. The degree of vacuum decreases due to the release to the surface. Therefore, it takes a long time to reach the target degree of vacuum, and the production efficiency decreases. Therefore, the aluminum alloy thick plate used in the chamber has a small amount of gas adsorbed on the surface of the thick plate located in the inner part of the chamber, and gas atoms dissolved in the thick plate may not be released even when the vacuum is high. Desired.
Therefore, when an aluminum alloy thick plate is used for a chamber, it is particularly effective to perform a surface smoothing treatment.

  As described above, the aluminum alloy thick plate obtained by the manufacturing method described above has good surface condition, flatness, and plate thickness accuracy. Therefore, in addition to semiconductor-related devices such as base substrates, transfer devices, vacuum device chambers, etc., it can be used for various applications such as electrical and electronic parts, manufacturing equipment, daily necessities, mechanical parts, etc. Recycling is also possible.

Next, the aluminum alloy thick plate according to the present invention will be described.
≪Aluminum alloy thick plate≫
The aluminum alloy thick plate is manufactured by the above-described method for manufacturing an aluminum alloy thick plate, and has an average crystal grain size of 400 μm or less.
By setting the average crystal grain size of the thick plate to 400 μm or less, it is possible to obtain a thick plate having excellent appearance after anodizing, and to reduce variations in lots.

  Further, when the size of the intermetallic compound in the thick plate is increased, color tone unevenness occurs in the cross section of the thick plate when the alumite treatment is performed. However, by reducing the size of the intermetallic compound, color unevenness is less likely to occur.

  As a method for measuring such a crystal grain size, for example, when the thickness of the ingot is T, the direction from one surface to the other surface is T / 5, 2T / 5, 3T / 5, 4T. This can be done by obtaining the average of the measured values at the thickness cross-sections at / 5 locations. As an example for obtaining such a measured value, a cross section of an aluminum alloy thick plate can be etched by a Barker method and cut by an optical microscope.

  The average crystal grain size is controlled by controlling the cooling rate during casting (the average cooling rate from the liquidus temperature to the solidus temperature) to 0.2 ° C./second or more to obtain an average crystal grain size of 400 μm or less. It can be. Furthermore, as described above, by adding 0.1% by mass or less of Ti or 0.3% by mass or less (in the case of an Al—Zn—Mg based alloy, 0.25% by mass or less) of Zr. The crystal grain size can be further refined.

  Regarding the corrosion resistance, the base substrate and the transfer device are used in a clean room, and therefore general corrosion resistance is not necessary. Even when used in a chamber for a vacuum apparatus, severe corrosion resistance is unnecessary because the environment is less exposed to corrosive gases.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Next, the effect of the embodiment that satisfies the claims of the present invention will be specifically described in comparison with a comparative example that departs from the claims of the present invention. Although the present invention is characterized by alloy components, dissolution process, dehydrogenation gas process, filtration process, casting process, slicing process, heat treatment process, etc., the present embodiment is particularly characterized by the slicing process. In the examples, the test was conducted mainly using a 5000 series Al-Mg series alloy as the alloy.

[First embodiment]
First, an aluminum alloy having the composition shown in Table 1 was dissolved, subjected to dehydrogenation gas treatment and filtration, and then cast to produce an ingot having a thickness of 500 mm. This ingot was hot-rolled after slicing or homogenizing heat treatment to produce an aluminum alloy thick plate (slice material, hot-rolled material) having a thickness of 20 mm × width of 1000 mm × height of 2000 mm.
Next, this slice material was heat-treated at 350 ° C. for 4 hours. The hot-rolled material was directly subjected to the next test.
The following tests were performed on the sliced material and the hot rolled material.

<Flatness evaluation test>
For the flatness evaluation, the amount of warpage (flatness) per 1 m in the casting direction was measured for the slice material, and the amount of warpage (flatness) per 1 m in the rolling direction was measured for the hot rolled material. A flatness of 0.4 mm / 1 m or less was accepted (O), and a flatness exceeding 0.4 mm / 1 m was rejected (X).

<Thickness accuracy evaluation test>
The thickness accuracy evaluation is performed by measuring the thickness of a total of 6 points from the four corners of the thick plate and the side of the half length portion in the length direction (longitudinal direction) to the inner 20 mm portion in the width direction. Measurement was performed using a meter. In each of the six points, ones of 19.94 mm or more and 20.06 mm or less were judged as good (◎), and those of 19.90 mm or more and 20.10 mm or less were judged as acceptable (◯).

<Strength test>
The strength was measured by preparing a JIS No. 5 test piece from an aluminum alloy thick plate, performing a tensile test, and measuring the tensile strength and 0.2% proof stress.
Those having a tensile strength of 180 N / mm ² or more were evaluated as acceptable (◯), and those having a tensile strength of less than 180 N / mm ² were evaluated as unacceptable (x).

<Alumite evaluation test>
The alumite evaluation was performed by observing the appearance of the surface and cross section of the aluminum alloy thick plate.
An alumite film having a thickness of 10 μm was formed on the surface and cross section of an aluminum alloy thick plate (sliced material, hot rolled material) by sulfuric acid alumite treatment (15% sulfuric acid, 20 ° C., current density 2 A / dm ² ). The appearance of the surface and the cross section of the thick plate was observed, and those having no unevenness in the appearance were determined to be acceptable (◯), and those having the unevenness were determined to be unacceptable (x).

In addition, since the crystal grain size of the thick plate affects the alumite property, the average crystal grain size of the thick plate was determined.
As an average crystal grain size measurement method, T / 5, 2T / 5, 3T / 5, 4T / 5, which are directed from one surface to the other surface when the ingot thickness is T, The measurement was performed by obtaining the average of the measured values in the thickness cross section of the part. Here, the cross section of the aluminum alloy thick plate was etched by the Barker method and cut by an optical microscope.
These results are shown in Tables 2 and 3.

表２、３に示すように、スライス材（合金成分１〜１３、１５〜２２）については、加工歪みが少なく、反りが小さかった。すなわち、平坦度が良好であった。また、板厚精度が優れていた。
合金成分１４では、Ｍｇが上限を超えるため、鋳造割れが発生し、製造が不可能であった。
合金成分１３では、Ｍｇの含有量が下限値未満のため、強度が不足した。
合金成分１〜１３、１７、２０〜２２は、アルミニウム合金厚板のアルマイト処理後の表面の外観にムラを生じなかった。
合金成分１５、１６、１８、１９は、それぞれ、Ｓｉ、Ｆｅ、Ｍｎ、Ｃｒの含有量が上限値を超えるため、粗大な金属間化合物が生じ、アルマイト処理後の表面の外観にムラを生じた。
合金成分１〜１３、１５〜２２については、アルミニウム合金厚板のアルマイト処理後の断面の外観にムラを生じなかった。

As shown in Tables 2 and 3, the slice materials (alloy components 1 to 13 and 15 to 22) had less processing distortion and small warpage. That is, the flatness was good. Moreover, the plate thickness accuracy was excellent.
In the alloy component 14, since Mg exceeded the upper limit, casting cracks occurred and production was impossible.
In the alloy component 13, since the Mg content was less than the lower limit, the strength was insufficient.
Alloy components 1 to 13, 17, 20 to 22 did not cause unevenness in the appearance of the surface of the aluminum alloy thick plate after the alumite treatment.
In alloy components 15, 16, 18, and 19, the contents of Si, Fe, Mn, and Cr exceeded the upper limit values, respectively, so that a coarse intermetallic compound was generated, and the surface appearance after anodizing was uneven. .
About alloy components 1-13, 15-22, the nonuniformity did not arise in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

  In addition, about the alloy components 17, 20, 21, and 22, content of Cu, Zn, Ti, and Zr exceeds an upper limit, respectively, The effect is saturated and it is inferior to economical efficiency.

On the other hand, with respect to the hot rolled material (alloy components 1 to 13, 15 to 22), processing strain was accumulated and warpage was large in the rolling direction. That is, the flatness was poor. In addition, the plate thickness accuracy was often inferior to that of the slice material.
In the alloy component 14, since Mg exceeded the upper limit, casting cracks occurred and production was impossible.
In alloy component 13, since the content of Mg was less than the lower limit value, the content of Mg was less than the lower limit value, so the strength was slightly inferior compared to other hot rolled materials.
In alloy components 15, 16, 18, and 19, the contents of Si, Fe, Mn, and Cr exceeded the upper limit values, respectively, so that a coarse intermetallic compound was generated, and the surface appearance after anodizing was uneven. .
About the alloy components 1-13, 15-22, the nonuniformity was produced in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

[Second Embodiment]
First, an aluminum alloy (alloy component 3) having the composition No. 3 shown in Table 1 was dissolved, subjected to dehydrogenation gas treatment and filtration, and then cast to produce an ingot having a thickness of 500 mm. This ingot was sliced to produce an aluminum alloy thick plate (slicing material) having a thickness of 20 mm × width of 1000 mm × height of 2000 mm. Next, the produced slice material was heat-treated under the conditions shown in Table 4.
The slice material was subjected to a flatness evaluation test, a plate thickness accuracy evaluation test, and a machinability evaluation test.

<Flatness evaluation test>
In the flatness evaluation, the amount of warpage (flatness) per 1 m in the casting direction was measured. A flatness of 0.4 mm / 1 m or less was accepted (O), and a flatness exceeding 0.4 mm / 1 m was rejected (X).

<Thickness accuracy evaluation test>
The thickness accuracy evaluation test method and evaluation criteria are the same as in the first embodiment.

<Machinability evaluation test>
For the evaluation of the machinability, that is, the chip breaking property, the number of chips per unit mass when drilling was performed with a drill was measured. Using a drill with a diameter of 5 mmφ, drilling was performed at a rotation speed of 7000 rpm and a feed rate of 300 mm / min, and the number of chips generated per 10 g was measured. Those less than 10 / 10g were regarded as rejected (x).
These results are shown in Table 4.

  As shown in Table 4, in Examples 1 and 2, since the heat treatment conditions satisfied the scope of the present invention, the flatness, plate thickness accuracy, and machinability were good. In Comparative Example 3, since the heat treatment was not performed, the flatness was poor. Further, the plate thickness accuracy was slightly inferior to those of Examples 1 and 2. In Comparative Example 4, since the heat treatment temperature was higher than the range of the present invention, the machinability was inferior. In Comparative Example 5, since the heat treatment temperature was lower than the range of the present invention, the flatness was poor. Further, the plate thickness accuracy was slightly inferior to those of Examples 1 and 2.

[Third embodiment]
Next, a 3000 series alloy was used for the test.
The test material was prepared by melting an aluminum alloy having the composition shown in Table 5, performing dehydrogenation gas treatment and filtration, and casting to prepare an ingot having a thickness of 500 mm. This ingot was hot-rolled after slicing or homogenizing heat treatment to produce an aluminum alloy thick plate (slice material, hot-rolled material) having a thickness of 20 mm × width of 1000 mm × height of 2000 mm.
Next, this slice material was heat-treated at 350 ° C. for 4 hours. The hot-rolled material was directly subjected to the next test.
The slice material and the hot-rolled material were subjected to a flatness evaluation test, a plate thickness accuracy evaluation test, a strength test, and an alumite evaluation test.
The evaluation method and evaluation criteria for each test are the same as in the first example. However, since the characteristics of the thick plate differ depending on the alloy type, the strength evaluation criteria were as follows.

The strength was determined to be acceptable (◯) when the tensile strength was 90 N / mm ² or more, and rejected (X) when the tensile strength was less than 90 N / mm ² .
The alloy compositions and the results are shown in Tables 5 and 6.

As shown in Table 6, the slice material (alloy components 23 to 26) had less processing distortion and small warpage. That is, the flatness was good. Moreover, the plate thickness accuracy was excellent.
The alloy component 25 was insufficient in strength because the Mn content was less than the lower limit.
In the alloy component 26, since the Mn content exceeds the upper limit value, a coarse intermetallic compound was generated, and the surface appearance after the alumite treatment was uneven.
Regarding the alloy components 23 to 26, the appearance of the cross section after the alumite treatment of the aluminum alloy thick plate was not uneven.

On the other hand, with respect to the hot rolled material (alloy components 23 to 26), processing strain was accumulated and warpage was large in the rolling direction. That is, the flatness was poor. In addition, the plate thickness accuracy was often inferior to that of the slice material.
The alloy component 25 had a slightly lower strength than other hot rolled materials because the Mn content was less than the lower limit.
In the alloy component 26, since the Mn content exceeds the upper limit value, a coarse intermetallic compound was generated, and the surface appearance after the alumite treatment was uneven.
About the alloy components 23-26, the nonuniformity was produced in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

[Fourth embodiment]
Next, a test was performed using a 6000 series alloy.
The test material was prepared by melting an aluminum alloy having the composition shown in Table 7, performing dehydrogenation gas treatment and filtration, and casting to prepare an ingot having a thickness of 500 mm. This ingot was hot-rolled after slicing or homogenizing heat treatment to produce an aluminum alloy thick plate (slice material, hot-rolled material) having a thickness of 20 mm × width of 1000 mm × height of 2000 mm.
Next, this slice material was heat-treated at 350 ° C. for 4 hours. The hot rolled material was used for the next step as it was. Further, the obtained thick plate was subjected to a solution treatment at 520 ° C., and an aging treatment was performed at 175 ° C. for 8 hours.
The slice material and the hot-rolled material were subjected to a strength test and an alumite evaluation test.
The evaluation method and evaluation criteria for each test are the same as in the first example. However, since the characteristics of the thick plate differ depending on the alloy type, the strength evaluation criteria were as follows.

The strength was determined to be acceptable (◯) when the tensile strength was 200 N / mm ² or more, and rejected (X) when the tensile strength was less than 200 N / mm ² .
The alloy compositions and the results are shown in Tables 7 and 8.

As shown in Table 8, regarding the slice material, the alloy components 29 and 31 had insufficient strength because the contents of Si and Mg were less than the lower limit values, respectively.
In the alloy component 30, since the Si content exceeds the upper limit value, a coarse intermetallic compound was generated, and the surface appearance after the alumite treatment was uneven.
In the alloy component 32, the Mg content exceeds the upper limit, the effect is saturated, and the economy is inferior.
Regarding the alloy components 27 to 32, the appearance of the cross section of the aluminum alloy thick plate after the alumite treatment was not uneven.

On the other hand, regarding the hot rolled material, the alloy components 29 and 31 were insufficient in strength because the contents of Si and Mg were less than the lower limit values, respectively.
In the alloy component 30, since the Si content exceeds the upper limit value, a coarse intermetallic compound was generated, and the surface appearance after the alumite treatment was uneven.
In the alloy component 32, the Mg content exceeds the upper limit, the effect is saturated, and the economy is inferior.
About the alloy components 27-32, the nonuniformity was produced in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

[Fifth embodiment]
Next, a test was performed using a 7000 series alloy.
The test material was prepared by melting an aluminum alloy having the composition shown in Table 9, performing dehydrogenation gas treatment and filtration, and casting to produce an ingot having a thickness of 500 mm. This ingot was hot-rolled after slicing or homogenizing heat treatment to produce an aluminum alloy thick plate (slice material, hot-rolled material) having a thickness of 20 mm × width of 1000 mm × height of 2000 mm.
Next, this slice material was heated at 300 ° C. for 4 hours to be heat-treated. The hot rolled material was used for the next step as it was. Further, the obtained thick plate was subjected to a solution treatment at 470 ° C., and an aging treatment was performed at 120 ° C. for 48 hours.
The slice material and the hot-rolled material were subjected to a strength test and an alumite evaluation test.
The evaluation method and evaluation criteria for each test are the same as in the first example. However, since the characteristics of the thick plate differ depending on the alloy type, the strength evaluation criteria were as follows.

The strength was determined to be acceptable (◯) when the tensile strength was 250 N / mm ² or more, and unacceptable (X) when the tensile strength was less than 250 N / mm ² .
The alloy compositions and the results are shown in Tables 9 and 10.

As shown in Table 10, regarding the slice material, the alloy components 35 and 37 had insufficient strength because the contents of Mg and Zn were less than the lower limit values, respectively.
In the alloy components 36 and 38, since the contents of Mg and Zn exceeded the upper limit values, the surface appearance after the alumite treatment was uneven.
About the alloy components 33-38, the nonuniformity did not arise in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

On the other hand, regarding the hot rolled material, the alloy components 35 and 37 had insufficient strength because the contents of Mg and Zn were less than the lower limit values, respectively.
In the alloy components 36 and 38, since the contents of Mg and Zn exceeded the upper limit values, the surface appearance after the alumite treatment was uneven.
About the alloy components 33-38, the nonuniformity was produced in the external appearance of the cross section after the alumite process of the aluminum alloy thick board.

  As described above, the manufacturing method of the aluminum alloy thick plate and the aluminum alloy thick plate according to the present invention have been described in detail with reference to the best embodiment and examples, but the gist of the present invention is not limited to the above description. The scope of rights should be broadly interpreted based on the description of the scope of claims. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

It is a figure which shows the flow of the manufacturing method of the aluminum alloy thick board which concerns on this invention. It is a schematic diagram which shows the center part of the ingot removed in a slicing process.

Explanation of symbols

S1 Melting process S2 Dehydrogenation gas process S3 Filtration process S4 Casting process S5 Slicing process S6 Heat treatment process S7 Surface smoothing process A Central part in the thickness direction of the ingot B Central part of the ingot T Thickness of the ingot 1

Claims (8)

Mg: 1.5% by mass or more and 12.0% by mass or less, Si: 0.7% by mass or less, Fe: 0.8% by mass or less, Cu: 0.6% by mass or less, Mn: 1 0.0 mass% or less, Cr: 0.5 mass% or less, Zn: 0.4 mass% or less, Ti: 0.1 mass% or less, and Zr: 0.3 mass% or less. And a melting step for melting an aluminum alloy consisting of Al and inevitable impurities in the balance,
A dehydrogenation gas step of removing hydrogen gas from the aluminum alloy dissolved in the melting step;
A filtration step of removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step;
A casting process for producing an ingot by casting an aluminum alloy from which inclusions have been removed in the filtration process;
A slicing step of slicing the ingot to a predetermined thickness;
An aluminum alloy thick plate characterized in that the aluminum alloy thick plate having a predetermined thickness sliced in the slicing step is subjected to a heat treatment step in which heat treatment is performed at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer in this order. Manufacturing method. Mn: 0.3 mass% or more and 1.6 mass% or less, Si: 0.7 mass% or less, Fe: 0.8 mass% or less, Cu: 0.5 mass% or less, Mg: 1 0.5% by mass or less, Cr: 0.3% by mass or less, Zn: 0.4% by mass or less, Ti: 0.1% by mass or less, Zr: 0.3% by mass or less And a melting step for melting an aluminum alloy consisting of Al and inevitable impurities in the balance,
A dehydrogenation gas step of removing hydrogen gas from the aluminum alloy dissolved in the melting step;
A filtration step of removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step;
A casting process for producing an ingot by casting an aluminum alloy from which inclusions have been removed in the filtration process;
A slicing step of slicing the ingot to a predetermined thickness;
An aluminum alloy thick plate characterized in that the aluminum alloy thick plate having a predetermined thickness sliced in the slicing step is subjected to a heat treatment step in which heat treatment is performed at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer in this order. Manufacturing method. Si: 0.2% by mass or more and 1.6% by mass or less, Mg: 0.3% by mass or more and 1.5% by mass or less, Fe: 0.8% by mass or less, Cu: 1.0% by mass %: Mn: 0.6% by mass or less, Cr: 0.5% by mass or less, Zn: 0.4% by mass or less, Ti: 0.1% by mass or less, Zr: 0.3% by mass or less A melting step of melting an aluminum alloy containing one or more and the balance being Al and inevitable impurities;
A dehydrogenation gas step of removing hydrogen gas from the aluminum alloy dissolved in the melting step;
A filtration step of removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step;
A casting process for producing an ingot by casting an aluminum alloy from which inclusions have been removed in the filtration process;
A slicing step of slicing the ingot to a predetermined thickness;
An aluminum alloy thick plate characterized in that the aluminum alloy thick plate having a predetermined thickness sliced in the slicing step is subjected to a heat treatment step in which heat treatment is performed at a temperature of 200 ° C. or higher and lower than 400 ° C. for 1 hour or longer in this order. Manufacturing method. Mg: 0.4% by mass or more and 4.0% by mass or less, Zn: 3.0% by mass or more and 9.0% by mass or less, Si: 0.7% by mass or less, Fe: 0.8% by mass % Or less, Cu: 3.0 mass% or less, Mn: 0.8 mass% or less, Cr: 0.5 mass% or less, Ti: 0.1 mass% or less, Zr: 0.25 mass% or less A melting step of melting an aluminum alloy containing one or more and the balance being Al and inevitable impurities;
A dehydrogenation gas step of removing hydrogen gas from the aluminum alloy dissolved in the melting step;
A filtration step of removing inclusions from the aluminum alloy from which hydrogen gas has been removed in the dehydrogenation gas step;
A casting process for producing an ingot by casting an aluminum alloy from which inclusions have been removed in the filtration process;
A slicing step of slicing the ingot to a predetermined thickness;
An aluminum alloy thick plate characterized in that the aluminum alloy thick plate having a predetermined thickness sliced in the slicing step is subjected to a heat treatment step in which heat treatment is performed at a temperature of 200 ° C. or higher and lower than 350 ° C. for 1 hour or longer in this order. Manufacturing method.   5. The production of an aluminum alloy thick plate according to claim 1, wherein after the heat treatment step, a surface smoothing treatment is further performed on the surface of the heat treated aluminum alloy thick plate. Method.   6. The method for producing an aluminum alloy thick plate according to claim 5, wherein the surface smoothing treatment is performed by one or more methods selected from a cutting method, a grinding method, and a polishing method.   In the slicing step, when the thickness of the ingot is T, the total thickness is T / 30 to T / 5 from the central portion in the thickness direction toward each surface in the thickness direction, with a uniform thickness. The method for producing an aluminum alloy thick plate according to any one of claims 1 to 6, wherein the thickness is removed.   An aluminum alloy thick plate manufactured by the method for manufacturing an aluminum alloy thick plate according to any one of claims 1 to 7, wherein an average crystal grain size is 400 µm or less. Thick plate.

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