JP2002012936A - Aluminum alloy sheet suitable for substrate for electronic and electric parts and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy sheet suitable for a substrate for electronic and electric parts, which is excellent in die cutting property, and tap workability or thread cutting property after stress-heating straightening, and to provide a method for producing this aluminum alloy sheet. SOLUTION: The aluminum alloy sheet is a cold-rolled sheet of an aluminum alloy containing Mg, Cu, Zn and Cr of each suitable content, wherein a bearing force in pulling this cold-rolled sheet in the direction of rolling, is 250 N/mm2 or more, and the bearing force in pulling this sheet in the direction of rolling, after this sheet is heat-treated at 250-300 deg.C for 1-8 h, is 250 N/mm2 or more. The aluminum alloy sheet is produced by hot-rolling at a temperature of 250 deg.C or below, after an Al alloy ingot containing Mg, Cu, Zn and Cr of each suitable content is homogenized at 400-600 deg.C for 1-15 h, and thereafter cold-rolling at a ratio of pressure reduction of 5-20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum (hereinafter abbreviated as Al) alloy sheet which is excellent in press punching property, tapping property after weight heating correction and thread cutting property, and is suitable for a substrate for electronic and electric parts. And its manufacturing method.

[0002]

2. Description of the Related Art A rolled plate of an Al-Mg alloy or the like (hereinafter, appropriately referred to as an Al alloy plate) is used for a substrate used for an electronic / electric component such as a semiconductor device or an IC component. Is used after press punching and weighted and heat-corrected. The weighted heating straightening is performed by sandwiching a press punched plate between flat plates and applying a weight to the sheet at a temperature of 250 to 300 ° C. for 1 to 8 hours, and by the weighted heating straightening, the punched plate becomes flat. While being molded, residual strain is removed, and deformation during use that causes a short circuit accident is prevented. The punched plate after the correction of the weighted heat is subjected to tapping and thread cutting necessary for assembling parts.

[0003]

However, the conventional Al alloy sheet has poor press punching properties, and the press punched sheet has problems in that tapping and thread cutting performed after correction by weight heating cannot be performed well. That is, burrs and the like were generated at the time of press punching, swaged portions were wobbled at the time of tapping, and threads were cut at the time of thread cutting. Therefore, the present inventors have studied the improvement measures of various problems in the press punching, tapping, thread cutting, etc., and in any case, by defining the proof stress when the material is pulled in the rolling direction to a predetermined value. The inventor found that it could be improved, and further studied to complete the present invention. An object of the present invention is to provide an Al alloy sheet having excellent press punching properties, and tapping properties and thread cutting properties of a press punched plate after weighted heating correction,
And a method for producing the Al alloy plate.

[0004]

According to the first aspect of the present invention,
0.3 to 6.0 wt% of Mg and 0.01 to 3.5 of Cu
wt%, Zn: 0.01 to 3.5 wt%, Cr: 0.0
A cold-rolled sheet containing 1 to 0.35 wt%, the balance being Al and unavoidable impurities, and having a yield strength of at least 250 N / mm ² when the cold-rolled sheet is pulled in the rolling direction;
After the cold-rolled sheet is heat-treated at 250 to 300 ° C. for 1 to 8 hours, the yield strength when pulled in the rolling direction is 250 N /
mm ² or more, which is an aluminum alloy plate suitable for a substrate for electronic / electric parts, which is characterized by being not less than ² mm ² .

According to a second aspect of the present invention, the content of Mg is set to 0.3 to 0.3.
6.0 wt%, Cu: 0.01 to 3.5 wt%, Zn: 0.01 to 3.5 wt% Cr: 0.01 to 0.35 wt
%, With the balance being Al and inevitable impurities, an aluminum ingot being homogenized at 450 to 600 ° C for 1 to 15 hours, then hot-rolled at a rising temperature of 250 ° C or less, and then a reduction of 5 to 20%. %, Which is a method for producing an aluminum alloy plate suitable for a substrate for electronic / electric parts, characterized by performing cold rolling under the condition of%.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, Mg contributes to improvement in strength (proof stress). The content is 0.3-6.0wt
The reason for specifying the percentage is that if the content is less than 0.3 wt%, the effect cannot be sufficiently obtained, and if the content exceeds 6.0 wt%, the rolling workability is reduced. Cu and Zn contribute to improvement in solderability and strength. The contents of Cu and Zn are both specified in the range of 0.01 to 3.5 wt%. The reason is that if the content is less than the lower limit, none of the effects can be sufficiently obtained. This is because rolling workability is reduced. Cr contributes to improvement in strength and heat resistance. The reason for defining the content to be 0.01 to 0.35% by weight is that if the content is less than 0.01% by weight, the effect cannot be sufficiently obtained, and if it exceeds 0.35% by weight, a huge crystallized product is formed during casting. This is because the rolling workability is reduced.

[0007] Of the impurity elements, if Si is excessively contained, rolling workability is reduced, and if the content of Fe and Mn is excessively large, press punching properties are reduced.
Is desirably 0.5 wt% or less, Fe is 0.6 wt% or less, and Mn is desirably 0.2 wt% or less. Mn coarsens crystal grains and lowers press punchability. Note that Ti or B may be added for crystal grain refinement. However, if the addition amount is too large, a large crystallized substance is formed at the time of casting to deteriorate workability. It is desirable that the content be specified at 2 wt% or less and B be set at 0.04 wt% or less.

In the present invention, the yield strength when the Al alloy sheet is pulled in the rolling direction is 250 N / m after cold rolling.
The reason for specifying the value of m ² or more is that press punching cannot be performed favorably at less than 250 N / mm ^2.
The reason why the proof stress after heat treatment at ~ 300 ° C for 1-8 hours is specified to be 250 N / mm ² or more is 250 N / m 2.
If it is less than m ² , tapping and thread cutting of the press punched plate after the weighted heating correction cannot be performed well. The heat treatment conditions are determined according to the weighted heating correction conditions.

The Al alloy sheet of the present invention is prepared by melting and casting an Al alloy having a predetermined composition by, for example, a DC method or the like to obtain an ingot. The ingot is homogenized, hot-rolled, and cold-rolled. In this order. Thickness 0.2 depending on the application
It is selected in the range of up to 6.0 mm.

[0010] The homogenizing treatment is carried out to eliminate the segregation of the alloying elements in the ingot and to distribute the alloying elements homogeneously. This homogenizing treatment improves the rolling workability. The homogenization treatment conditions were set at a temperature of 450 to 600 ° C. for 1 to 15 hours.
The reason for specifying the time is that the effect is not sufficiently obtained even at less than 450 ° C. or less than 1 hour, and at more than 600 ° C., the low melting point compound is melted to deteriorate the rolling processability.
If the time is exceeded, the effect is saturated and only the cost is increased.

In the present invention, by setting the rising temperature in hot rolling to be low, recrystallization is suppressed, work hardening in the next cold rolling is increased, and good press punchability is realized. Prevention of precipitation of alloying elements such as Mg, Cu, Zn and the like, and precipitation at the time of subsequent correction by weight heating to enhance the proof stress of the stamped plate, thereby realizing good tappability and threadability. In the present invention, the reason for setting the rising temperature in the hot rolling to 250 ° C. or less is that if the temperature exceeds 250 ° C., recrystallization proceeds and sufficient proof stress cannot be obtained after cold working, and after hot rolling, Mg , Cu, Zn and the like are precipitated in a large amount, so that sufficient precipitation hardening cannot be obtained at the time of correction by weighted heating.

In the present invention, the reason why the rolling reduction in cold rolling is specified to be 5 to 20% is that if it is less than 5%, the yield strength after cold rolling is less than 250 N / mm ² , and good press punchability is obtained. If it is not obtained and exceeds 20%, the work hardens too much and the proof stress exceeds 250 N / mm ² , the proof stress sharply decreases at the time of correction by weighted heating, and the tappability and threading property decrease.

[0013]

The present invention will be described below in detail with reference to examples. (Example 1) An Al alloy having the composition specified in the present invention shown in Table 1
According to method C, thickness 500 mm, width 1360 mm, length 4
The ingot was cast into a 000 mm ingot, and the ingot was subjected to homogenization treatment at 550 ° C. for 5 hours. Then, hot rolling was started directly from the homogenization treatment temperature, and after hot rolling, cold rolling was performed. An Al alloy plate having a thickness of 3.0 mm was manufactured. The rising temperature in hot rolling is 230 ° C, and the rolling reduction in cold rolling is 15%.
And

Comparative Example 1 An Al alloy plate was produced in the same manner as in Example 1 except that an ingot of an Al alloy having a composition not specified in the present invention shown in Table 1 was used.

For each of the Al alloy sheets produced in Example 1 and Comparative Example 1, the proof stress A was measured, and the Al alloy sheet was press-punched into a substrate shape, and the press-punchability was examined. Next, the pressed blank was heat-treated at 300 ° C. for 8 hours, the proof stress B was measured, and the threading property was examined. The proof stress was measured according to JIS 4000 (No. 5 test piece). The test piece was cut out so that the tensile direction coincided with the rolling direction. The press punching property was observed by observing each of 100 press punched plates. If no defect such as burrs occurred at all, it was good (O), and if even one defect occurred, it was poor (X).
It was determined. The threading property was determined to be good (O) when 100 punched plates were threaded and no defect such as thread cut occurred at all (good) and poor (x) when even one defect occurred. . Table 2 shows the results.

[0016]

[Table 1]

[0017]

[Table 2]

As is apparent from Table 2, the Al of the present invention example
All of the alloy plates (Nos. 1 to 5) had a proof stress A satisfying the specified value of the present invention and were excellent in press punching properties. Further, the proof stress B after heat treatment at 300 ° C. for 8 hours satisfied the specified value of the present invention and was excellent in threading property. On the other hand, in Comparative Example No. In No. 6, since the amount of Mg was small, the proof stress A was reduced and the press punching property was reduced. In addition, the precipitation hardening was small, the proof stress B was low, and the threading property was also reduced by the heat treatment at 300 ° C. for 8 hours. No. No. 7 was inferior in castability and rolling workability due to the large amount of Mg, Zn, and Cr, and it was difficult to manufacture an Al alloy sheet. The tapability of the inventive sample was also examined, but none of the defects, such as the swaged portion, occurred.

Example 2 Table 1 shows the composition of the present invention. D alloy ingot of D (thickness 500mm, width 1360)
mm, 4000 mm in length) at 550 ° C. for 5 hours. After the homogenization, hot rolling is started at that temperature, and after hot rolling, cold rolling is performed to obtain a 3.0 mm thick sheet. Al
An alloy plate was manufactured. The rising temperature in hot rolling and the rolling reduction in cold rolling were variously changed within the range of the present invention. The rolling reduction was varied by variously changing the thickness after hot rolling.

Comparative Example 2 An Al alloy sheet was manufactured in the same manner as in Example 2 except that the rising temperature in hot rolling and the rolling reduction in cold rolling were variously changed outside the scope of the present invention. .

With respect to each of the Al alloy sheets manufactured in Example 2 and Comparative Example 2, the proof stresses A and B, press punching property, and threading property were examined in the same manner as in Example 1.
Table 3 shows the results.

[0022]

[Table 3]

As is apparent from Table 3, the Al of the present invention example
All the alloy sheets (Nos. 8 to 12) had a proof stress A satisfying the specified value of the present invention and were excellent in press punching properties.
Further, the proof stress B after heat treatment at 300 ° C. for 8 hours satisfied the specified value of the present invention and was excellent in threading property. In contrast,
No. of the comparative example. No. 13 had a high rise temperature in hot rolling, and In No. 14, the rolling reduction in cold rolling was small, so that the proof stress A was lowered and the press punching property was inferior. No. In Sample No. 13, the solid solution amount of the alloying element was small, so that precipitation hardening did not occur by heat treatment at 300 ° C. for 8 hours, the proof stress B was reduced, and the threading property was poor. No. No. 15 was 300 ° C. 8
Due to the heat treatment for a long time, the material softened rapidly, and the proof stress B was less than the value specified in the present invention. In addition, although the tapping workability was also examined with respect to the products of the present invention, no troubles such as shaking of the swaged portion occurred at all.

[0024]

As described above, the Al alloy sheet of the present invention is a cold-rolled sheet containing an appropriate amount of alloying elements such as Mg, Cu, Zn, and Cr, and has a yield strength when pulled in the rolling direction. Is more than 250N / mm ² , so it has excellent press punching property,
In addition, since the proof stress when pulled in the rolling direction after heat treatment at 250 to 300 ° C. for 1 to 8 hours is 250 N / mm ² or more, it is excellent in tappability and threading properties after weighted heating correction, and is suitable for electronic and electrical equipment parts. Useful for substrates. Further, the Al alloy plate can be easily manufactured by a conventional method in which the conditions for homogenizing the ingot, the rising temperature in hot rolling, and the rolling reduction in cold rolling are specified. Therefore, an industrially remarkable effect is achieved.

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Claims (2)

[Claims] 1. Mg: 0.3-6.0 wt%, Cu: 0.01-3.5 wt%, Zn: 0.01-3.5 wt%
%, Cr is contained at 0.01 to 0.35 wt%, and the balance is A
and a unavoidable impurity, wherein the cold rolled sheet has a yield strength of 250 when pulled in the rolling direction.
N / mm ² or more, for the electronic and electronic parts, wherein the cold rolled sheet is heat-treated at 250 to 300 ° C. for 1 to 8 hours, and then has a yield strength of 250 N / mm ² or more when pulled in the rolling direction. Aluminum alloy plate suitable for substrate. 2. Mg: 0.3-6.0 wt%, Cu: 0.01-3.5 wt%, Zn: 0.01-3.5 wt%
% Cr in an amount of 0.01 to 0.35 wt%, with the balance being Al
And 4 ingots of aluminum alloy consisting of unavoidable impurities
After homogenizing at 50-600 ° C for 1-15 hours,
Hot rolling at a rising temperature of 50 ° C. or less, and then a rolling reduction of 5
A method for producing an aluminum alloy sheet suitable for a substrate for electronic / electric parts, characterized in that the aluminum alloy sheet is cold-rolled under conditions of up to 20%.