JP2001040444A - Aluminum alloy plate material for rpecision working and production therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy plate in which crystal grains are fine and uniform and having high strength by allowing it to have a specified compsn., allowing the plate thickness, tensile strength, the average crystal grain size in the plate thickness direction in the cross-section of the plate thickness in the rolling direction and the aspect ratio of the crystal grain size respectively to have specified value and controlling the ratio of respective aspect ratios of the crystal grain sizes at the 1/4 place and 1/2 place of the plate thickness to a specified range. SOLUTION: This alloy plate material has a compsn. contg., by weight, 0.40 to 0.80% Si, 0.15 to 0.40% Cu, 0.8 to 1.2% Mg and 0.04 to 0.35% Cr, and moreover contg., as impurities or significant elements, <=0.15% Mn and <=0.7% Fe, and the balance substantial Al and has 30 to 100 mm plate thickness and >=200 MPa tensile strength, and in which the average crystal grain size in the plate thickness direction in the cross-section of the plate thickness in the rolling direction is <=1.0 mm, the aspect ratio of the crystal grain size in the cross-section is <=3, and also, in the case the aspect ratios of the crystal grain sizes at the 1/4 place and 1/2. place of the plate thickness are respectively defined as A and B, the value of A/B satisfies 0.7<=A/B<=1.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor-related device,
For example, the present invention relates to an ultra-high vacuum vessel used for plasma generation or vapor deposition, ancillary equipment such as transport, an aluminum alloy plate material for precision processing such as a base, etc., and a method for manufacturing the plate material.

[0002]

2. Description of the Related Art Articles such as an ultrahigh vacuum container, incidental equipment such as a conveyor, and a base, as described above, are generally cut out from a thick plate material and precision-smooth-cut to produce a precision processed product. . For example, JIS A
6061 (referred to as "61S" in the present invention) is widely used in the precision processed products because it has strength and is easy to process. A processed product precisely processed from such a plate material is provided with hard alumite for maintaining a high vacuum or for electrical insulation.

Japanese Patent Application Laid-Open No. 61-163232 discloses an Al-Mg-Cu alloy having a fine crystal grain structure. It has been proposed to be used for such purposes. The alloy having a fine grain structure described therein is an Al-Mg-Cu-based alloy containing 0.8 to 1.2% of Si, and the method of manufacturing the alloy material includes the steps of: Before hot rolling, heat treatment is performed in one stage at a specific temperature, or one stage heat treatment at a temperature lower than the specific temperature, and as a second stage, a second stage heat treatment is performed at a higher temperature. Give
A method for producing a 4 to 6 mm plate having a plate thickness of 50 μm or less is disclosed.

[0004]

However, according to the conventional general method as described above, due to recent technical advances, gas leakage and instability of placement of precision-machined products or, as a result, high-performance dimensional components can be obtained. Since there is a risk that there is no such thing, more precise cutting is required.However, conventional products used for precision processed products have large crystal grains or non-uniform size and color after hard alumite. There is a possibility that unevenness may occur and the fear of insulation failure in the insulating part cannot be avoided.

[0005] Further, the method according to the plate manufacturing method described in the above-mentioned Japanese Patent Application Laid-Open No. 61-163232 is intended for a thin plate used for a wheel rim or the like, and contains many intermetallic compounds such as Mg ₂ Si. There is a problem that precision cutting is hindered when cutting is performed.

[0006]

SUMMARY OF THE INVENTION The present invention has been studied to solve the above-mentioned problems in the prior art, and has reduced intermetallic compounds such as Mg ₂ Si, and has high strength and large thickness. Even if the crystal grains are fine and uniform, it has succeeded in obtaining a precision-working aluminum alloy sheet material and a method for producing the same, which can obtain a sheet in which color unevenness is not visible even when hard alumite is applied, as follows. is there.

That is, the present invention firstly provides Si; 0.40 to 0.8;
0 wt%, Cu: 0.15 to 0.40 wt%, Mg: 0.8 to 1.2 wt
%, Cr: 0.04 to 0.35% by weight, Mn: 0.15% by weight or less and Fe: 0.7% by weight or less as impurities or significant elements, and the balance substantially consists of aluminum. Refining agent, ie, Ti; 0.005 to 0.20 wt%,
Or Ti: 0.005 to 0.20 wt% and B; 0.000
Contains 5 to 0.02 wt%, the thickness of the plate is 30 to 100 mm
The tensile strength is 200 MPa or more, and the average grain size in the thickness direction of the thickness section parallel to the rolling direction is 1.0 mm or less, and the aspect ratio of the grain size on the surface is 3 mm or less. In the following, when the length / width ratio of the crystal grain size at a location of 1/4 of the plate thickness is A, and the length / width ratio of the crystal grain size at a location of 1/2 of the plate thickness is B And the value of A / B is 0.7
≦ A / B ≦ 1.5 is an aluminum alloy sheet for precision machining. That is, since the amount of Si is small, Mg ₂ Si
Since the amount of the intermetallic compound is small and the precision workability is good, and the crystal grain size is fine and uniform, even if a hard alumite film is applied, the color unevenness is not visually discriminated.

Further, the present invention provides, secondly, Si; 0.40 to 0.80;
wt%, Cu: 0.15 to 0.40 wt%, Mg: 0.8 to 1.2 wt%,
Cr: 0.04 to 0.35 wt%, as impurities or significant elements
Mn: 0.15 wt% or less and Fe: 0.7 wt% or less,
The ingot substantially consisting of aluminum is heated and held at 530 to 570 ° C. for 40 minutes or more as a first-stage heat treatment, and then cooled to 500 to 450 ° C. after completion of the first-stage heat treatment as a second-stage heat treatment. Hold for 30 minutes or more, set the time from the start of cooling after the completion of the first stage heat treatment to the end of the hold for 30 minutes or more to 5 hours or more, and then perform hot rolling and reduce the rolling reduction of at least the final pass of the hot rolling. After hot rolling at a temperature of 400 to 350 ° C. in the range of 30 to 100 mm and a temperature of 400 to 350 ° C. after rolling at 30% or more, reheating after cooling at that temperature or after quenching after solution treatment, Thereafter, a method for producing an aluminum alloy sheet for precision processing characterized by age hardening treatment, wherein the Mg ₂ Si compound is coarsely precipitated by the second-stage heat treatment, and the final rolling ratio of hot rolling is increased. Setting and hot rolling It has the effect of lowering the end temperature and forming fine and uniform recrystallized grains in the subsequent solution treatment.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The components contained in the plate material according to the present invention as described above and the proportions thereof will be described in detail as follows.

Si: 0.40 to 0.80 wt% Mg; 0.8 to 1.2 wt% Si is added together with Mg for the purpose of imparting strength in the initial stage of Mg ₂ Si precipitation by artificial aging treatment. If it is less than the lower limit, the strength is insufficient due to the aging treatment. On the other hand, when the value exceeds the upper limit, the quenching sensitivity becomes high, and when the thickness of the plate is large, it becomes difficult to quench uniformly. If Si exceeds the upper limit, the corrosion resistance also decreases. Preferably, Si is less than 0.80 wt%, more preferably 0.70 wt% or less. Also Mg
Is preferably at most 1.1 wt%.

Cu: 0.15 to 0.40 wt% Cu is added for the purpose of imparting strength in the initial stage of CuAl ₂ precipitation by artificial aging treatment. If the amount is less than the lower limit, the strength is insufficient due to the age hardening treatment. If it exceeds the upper limit, the corrosion resistance decreases. Preferably it is 0.30 wt% or less.

Cr: 0.04 to 0.35 wt% Cr is added for the purpose of refining recrystallized grains to prevent intergranular corrosion cracking. If it is less than the lower limit, the effect is reduced. On the other hand, if the upper limit is exceeded, the effect of inhibiting recrystallization becomes strong. If the sheet thickness is large, the recrystallized grains may become coarse in the hot rolling step and the subsequent artificial aging treatment.
Further, when the quenching sensitivity is increased and the thickness of the plate is large, it is difficult to quench uniformly. Preferably 0.30 wt% or less,
More preferably, the content is 0.20% by weight or less.

Mn: 0.15 wt% or less When Mn is contained as an impurity or a significant additive component, it has the effect of refining recrystallized grains in the same manner as Cr, but if it exceeds the upper limit, the content of Al ₆ (Mn, Fe) etc. Intermetallic compounds are crystallized and reduce precision workability. Preferably it is 0.10 wt% or less, more preferably 0.05 wt% or less.

Fe: 0.7 wt% or less Mn, Cr when Fe is contained as an impurity or a significant additive component
In the same manner as described above, it has the effect of refining the recrystallized grains, but if it exceeds the upper limit, intermetallic compounds such as Al ₆ (Fe, Mn) are crystallized and the precision workability is reduced. Preferably it is 0.60 wt% or less, more preferably 0.5 wt% or less.

The fact that the balance substantially consists of aluminum means that the aluminum contains, if necessary, the following elements. That is, where the main elements that bring about the effects of the present invention are the aforementioned Si, Cu, Mg, and Cr, significant or impurity elements that are not contained to the extent that the effects of the present invention are not particularly hindered as other elements other than these elements. It means aluminum contained. That is, when casting an ingot for rolling, a significant element is added by rapid cooling casting so that the ingot does not cause casting cracks. Such elements are typically, for example, 0.005 to 0.20 wt% of Ti, B
0.0005-0.02 wt% of Zr, 0.005-0.20 wt% of Zr
One or more of these are added and contained. In particular, these elements are not elements that impair the effects of the present invention, but are elements that may be added as necessary.

Other impurities These indicate components other than Mn and Fe as impurities, and the main components as such components are Ni, Zn, Ca, V
Ni: 0.01 wt% or less, Zn: 0.3 wt%
Hereinafter, if the content of Ca is about 0.02% by weight or less and the content of V is about 0.02% by weight or less, the effects of the present invention are not impaired. In addition, as a casting crack inhibitor generally added at the time of casting, 0.1
005 to 0.20 wt% or 0.005 to 0.2% of Ti.
A composite content of 20 wt% and 0.0005 to 0.02 wt% of B has the above-described effect of preventing cracking, and is therefore preferable.

Since the aluminum alloy sheet for precision machining according to the present invention is manufactured by cutting out a product from the intended use as described above, the thickness of the original sheet is 30 to 100 mm.
It is. On the other hand, if it exceeds the upper limit of 100 mm, the aluminum alloy sheet according to the present invention, which is excellent in machinability, has high strength, and is suitable for precision processed products having uniform and fine crystal grains cannot be obtained. The aluminum alloy sheet for precision processing is required to be robust from its use, and has a tensile strength of 200 MPa or more, preferably 295 MPa or more.

In the high vacuum apparatus as described above, a hard alumite film is provided for electrical insulation, but the average crystal grain size in the thickness direction of a plane parallel and perpendicular to the rolling direction is 1.0 mm or less. When the thickness is preferably 0.8 mm or less, more preferably 0.7 mm or less, color unevenness in a homogeneous film is not visually observed. This is considered to be because the difference in the reflected light of the light incident on the film due to the difference in the orientation of the crystal grains becomes uniform as a whole, and is not visually recognized as color unevenness.

When the length / width ratio of the crystal grain size at a location 1/4 of the plate thickness is A, and the length / width ratio of the crystal grain size at a location 1/2 of the plate thickness is B. In addition, the value of A / B is 0.7 ≦ A / B ≦ 1.5, preferably 0.9 ≦ A / B ≦ 1.2.
In this case, the color unevenness due to the difference in the position of the film surface is eliminated. This is presumed to be because the crystal grain size of the precision-processed surface becomes uniform as a whole and is not visually recognized as color unevenness.

Next, a preferred method of manufacturing the aluminum alloy sheet for precision processing according to the present invention will be described. First, a molten metal of the above-described component is cast by DC casting by a conventional method to obtain an ingot. Before the ingot is hot-rolled, a two-stage heat treatment is performed. When performing this heat treatment, the ingot may be left as it is without being chamfered.However, if heat treatment is performed after chamfering, heat treatment after heat treatment and heating for hot rolling again can be omitted, so heat energy Is advantageous.

As the first stage heat treatment, 530 to 570
Heat to and hold at 40 ° C for 40 minutes or more. This is a treatment for homogenizing segregation of components and the like generated at the time of casting and dissolving the contained elements. When the heating temperature is less than 530 ° C. and the holding time is less than 40 minutes, such action is small, and the crystal grains are fine. Effect is difficult to obtain. In addition, high strength cannot be obtained by age hardening.

As the second stage heat treatment, after the first stage heat treatment is completed, cooling is performed, and the temperature is kept at 500 to 450 ° C. for 30 minutes or more, and after the first stage heat treatment is completed, the cooling is maintained for 30 minutes or more. The time until the end is 5 hours or more. In this method, the Mg ₂ Si compound is coarsely precipitated by holding at 500 to 450 ° C. for 30 minutes or more, and the time from the start of cooling after the completion of the first stage heat treatment to the end of the holding for 30 minutes or more is set to 5 hours or more. As a result, compounds such as Al ₆ (Fe, Mn) are coarsely precipitated, and are easily recrystallized in the next hot rolling step to facilitate fine recrystallization, and are finely uniform by subsequent solution aging hardening. It is intended to obtain a suitable recrystallized grain structure.

The ingot subjected to the above-described one- or two-stage treatment is hot-rolled, and has a thickness of 30 to 30 through a plurality of passes.
The hot rolling is completed at a temperature of 400 to 350 ° C. Such a thickness is necessary for manufacturing a high vacuum vessel by cutting, and in order to make recrystallized grains uniform and fine grains, it is preferable to increase the rolling ratio in each pass of hot rolling. For example, at the stage where the thickness of the ingot is large at the beginning of hot rolling, it is preferable that the rolling thickness be 30 mm or more. When the rolling ratio is increased, the applied strain is large,
Each pass refines the recrystallized grains. At least the final pass hot rolling ratio is set to 30% or more to uniformly apply processing strain,
By finishing at a temperature of 400 to 350 ° C., a large number of recrystallization nuclei are uniformly generated, and until hot rolling is completed and cooled, a part of the hot-rolled sheet is uniformly and finely recrystallized. Along with the age hardening treatment, the average grain size in the sheet thickness direction (horizontal size shown in FIG. 2) of the sheet thickness section parallel to the rolling direction in the entire sheet thickness area is not more than 1.0 mm and uniform. be able to.

When the hot rolling reduction of the final pass in the hot rolling as described above is less than 30% and the end temperature is more than 400 ° C., the applied strain is small, and the recrystallized grains are formed in the subsequent solution treatment. The size is coarsened and the uniform fine grain size of the present invention cannot be obtained. Also, the hot rolling rate of the final pass is 30%
If the end temperature is less than 350 ° C., the applied strain is non-uniform on the sheet surface and inside the sheet, and the recrystallized grain size in the sheet thickness direction by dynamic recrystallization after hot rolling and subsequent solution treatment. Is not preferred because it becomes non-uniform. The higher the hot rolling reduction of the final pass, the better, and preferably 3
It is at least 5%, more preferably at least 40%. The end temperature is preferably lower within the above range.

The hot-rolled sheet after the hot rolling is cooled once or heated from the hot-rolling end temperature to perform a solution treatment. This solution treatment is based on the age hardening contributing components Si, Mg,
In addition to the purpose of solid solution of Cu, the purpose is to recrystallize finely and uniformly after hot rolling is completed or to recrystallize an unrecrystallized portion. The solution treatment temperature is 450 ° C. or higher, preferably 500 ° C. or higher, and heated for 1 minute or more, preferably 10 minutes or more.
Hold for more than a minute. If it is less than 450 ° C. or less than 1 minute, the applied strength tends to be insufficient. The upper limit of the heating temperature is a temperature at which no panning is performed, that is, about 550 ° C., and the upper limit of the holding time is 2 hours, which is disadvantageous in terms of thermoeconomics.

After the solution treatment as described above, quenching is performed immediately from the temperature. The quenching treatment may be performed in oil, but is preferably performed in water because the cooling rate is high. In the quenching treatment, when the plate thickness is large as in the present invention, the strain inside the plate is unevenly distributed. It is preferable to apply a process for imparting permanent strain to make the internal strain of the plate uniform. After quenching, age hardening is performed to improve the strength. In the case of natural aging, when the age hardening treatment is maintained for 4 days or more, a strength of 200 MPa or more can be imparted. When a high strength is required, a strength of 295 MPa or more can be obtained by holding at a temperature of 150 to 170 ° C. for 5 hours or more. Further, when high strength and elongation are required, it is preferable that the temperature is maintained at 170 to 185 ° C. for 5 hours or more. 5 with tempering temperature below 150 ° C
If it is less than the time, a sufficiently high strength cannot be obtained. Also 18
If it exceeds 5 ° C., it becomes soft and it is difficult to obtain a strength of 295 MPa or more. The holding time has an optimum value depending on the strength to be obtained, and the strength at which holding at 160 ° C. for 8 hours is the highest is obtained.

[0027]

[Example of manufacturing method] An ingot having a composition shown in the following Table 1 and having a thickness of 530 mm was cast by an ordinary method. That is, Table 2 below shows details of the production process. Each of the ingots shown in Table 1 was subjected to the first-stage heat treatment, and then to the second-stage heat treatment. Next, it is hot-rolled to form a hot-rolled sheet having a thickness of 80 mm, and then subjected to a solution treatment at 530 ° C. for 20 minutes.
Age hardening treatment was performed after water quenching. Age hardening treatment is 16
The test was performed at 0 ° C. × 8 hours.

[0028]

[Table 1]

[0029]

[Table 2]

The tensile strength and average crystal size of each of the samples obtained as described above were measured. The crystal grain size of the sample as shown in FIG. 1 was as shown in FIG. The size was measured at the following measuring points. Measurement Location and Measurement Method of Crystal Grain Size: The crystal grains having a thickness cross section parallel to the rolling direction were observed with an optical microscope to measure the size. For the average grain size, a straight line of 1 cm was drawn in the thickness direction, and the distance of this straight line was divided by the number of crystal grains crossed by the straight line, and the quotient was defined as the average grain size.

A current was applied under the following conditions to form a hard alumite film, and the presence or absence of color unevenness was visually observed.

The results of the test measurement and the observation as described above are summarized in Table 3 below, and those of Samples Nos. 1 and 2 according to the requirements of the present invention have strength characteristics. Good, fine grain size, 1/4 and 1 thickness
/ 2, the crystal grain size is small, the value of A / B is 1 or more for the aspect ratios A and B, and the ratio is uniform, and the degree of color unevenness is so good that it is not visible. It has been confirmed that the aluminum alloy sheet is very preferable as an aluminum alloy sheet to be used for applications requiring precise processing.

[0033]

[Table 3]

[0034]

According to the present invention as described above, the crystal grains are fine and uniform, there is little color unevenness after hard alumite, and it is possible to provide a very preferable product as an aluminum alloy sheet for precision machining. Therefore, the invention is industrially effective.

[Brief description of the drawings]

FIG. 1 is a perspective view of an aluminum alloy sheet according to the present invention, showing a state of crystal grains.

FIG. 2 is an enlarged explanatory view showing a state of crystal grains in a portion A in FIG. 1 and also shows a relationship between a vertical size and a horizontal size of the crystal grains and a relationship between a rolling direction and a sheet thickness direction. is there.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C22F 1/00 693 C22F 1/00 693A 693B 694 694A 694B

Claims (3)

[Claims] (1) Si: 0.40 to 0.80 wt% Cu; 0.15 to 0.40 wt% Mg; 0.8 to 1.2 wt% Cr; 0.04 to 0.35 wt% and impurities Or, as significant elements, Mn; 0.15 wt% or less, Fe; 0.7 wt% or less, the balance is substantially made of aluminum, the thickness of the plate is 30 to 100 mm, and the tensile strength is 200 MPa or more. In addition, the average crystal grain size in the thickness direction of the sheet thickness cross section parallel to the rolling direction is 1.0 mm or less, the aspect ratio of the crystal grain size on the surface is 3 or less, and 1/4 of the sheet thickness. When the vertical / horizontal ratio of the crystal grain size at the position of No. is A and the vertical / horizontal ratio of the crystal grain size at the half position of the plate thickness is B, A /
An aluminum alloy sheet for precision machining, wherein the value of B satisfies 0.7 ≦ A / B ≦ 1.5. 2. Containing Si: 0.40 to 0.80 wt% Cu; 0.15 to 0.40 wt% Mg; 0.8 to 1.2 wt% Cr; 0.04 to 0.35 wt% Or as significant elements: Mn; 0.15 wt% or less, Fe; 0.7 wt% or less, and Ti; 0.005 to 0.20 wt% or Ti; 0.005 to 0.20 wt% and B; 0.0005-0.02wt%, the balance consists of Al and other impurities, the thickness of the plate is 30-100mm, the tensile strength is 200MPa or more, and the plate thickness cross section parallel to the rolling direction The average grain size in the sheet thickness direction is 1.0 mm or less, the aspect ratio of the grain size on the surface is 3 or less, and the length / When the width ratio is A, and the length / width ratio of the crystal grain size at a location 1/2 of the plate thickness is B, A
An aluminum alloy sheet for precision machining, wherein the value of / B is 0.7 ≦ A / B ≦ 1.5. 3. An alloy containing Si: 0.40 to 0.80 wt% Cu; 0.15 to 0.40 wt% Mg; 0.8 to 1.2 wt% Cr; 0.04 to 0.35 wt% Alternatively, an ingot containing Mn: 0.15 wt% or less and Fe: 0.7 wt% or less as a significant element and the balance substantially consisting of aluminum is heated to 530 to 570 ° C. for 40 minutes or more as a first-stage heat treatment. After the holding, the second-stage heat treatment is followed by cooling after the completion of the first-stage heat treatment, and is maintained at 500 to 450 ° C. for 30 minutes or more.
The time from the start of cooling after the end of the stage heat treatment to the end of the holding for 30 minutes or more from the start of cooling is set to 5 hours or more. Thickness is 30 ~ 100mm, temperature is 400 ~ 350
Manufacture of aluminum alloy sheet for precision machining characterized by finishing hot rolling in the range of ℃, cooling from that temperature or after cooling, reheating, solution treatment, quenching, and then age hardening Method.