JPH01133602A - Manufacture of deformed section bar strip - Google Patents

Abstract

PURPOSE:To manufacture a deformed section bar strip having good dimensional accuracy by rolling a thick central part and both thin side parts by respective specific drafts for manufacturing a protrudent section bar strip consisting of a thick central part and both thin side parts by repeating rolling and annealing so that a copper alloy bar strip is formed into a specific shape. CONSTITUTION:A protrudent deformed section bar strip consisting of a thick central part 2 and both thin side parts 3, 3 integrally formed in the width direction of the bar strip is manufactured after a copper alloy is formed into a bar strip by hot and cold rolling. In this time, the thick central part 2 and the both thin side parts 3, 3 are rolled by forming ratios of >=40% and >=65% respectively after the copper alloy strip is annealed at a temp. in 400-650 deg.C. By repeating that annealing and rolling by plural times, a protrudent section bar strip 1 having good dimensional accuracy is manufactured with the good material yield.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is often used in lead materials for transistors, which are one of the semiconductor elements often used in electronic and electrical equipment, and has particularly remarkable heat dissipation properties. The present invention relates to a method for manufacturing strips with irregular cross-sections suitable for required power transistors and IC devices.

(Problems to be solved by the prior art and the invention) Such irregular cross-section strips are formed into convex cross-section strips (1) as shown in Fig. 1.
It has a shape in which thinner parts (3) are integrally formed on both sides of a central thicker part (2). Conventionally, to manufacture this irregular cross-section strip, a thin section was formed by cutting both sides in the longitudinal direction of the surface of a strip with a rectangular cross section, and a thick section was formed by cutting the central section or not cutting it. . However, this cutting method has the drawbacks of poor material yield and high processing costs in order to improve dimensional accuracy. Therefore, the cross-section in the axial direction of the roll is transferred from side to side between the lower surface of the roll, which has grooves corresponding to the cross-sectional shape of the inside thickness of the irregular cross-section strip, and the fixed die set opposite to the lower surface. A rolling process has been developed in which a rectangular strip is supplied and the strip is rolled in the width direction to form thick and thin sections at the same time, and this method has greatly contributed to improving quality and reducing costs.

However, in this rolling method, the rolling rate is significantly different between the thick part and the inside of the book, so the annealing process after forming causes non-uniformity of the structure, resulting in large variations in properties and significant uniformity. This was a problem because it caused a decrease in dimensional accuracy, and at the same time caused problems with dimensional accuracy, greatly reducing productivity and increasing costs.

(Means for Solving the Problems) In view of this, the present invention has been developed as a result of various studies, and has developed a method for manufacturing a strip of irregular cross-section that has good characteristics and is excellent in manufacturability. That is, in a method of manufacturing a strip of irregular cross-section in which a thick part and a thin part are integrally formed in the width direction by rolling conditions, after annealing the strip, the thick part is 40% or more and the thin part is 65%. It is characterized by rolling at the above processing rate and then rough rolling or rolling and annealing one or more times, and it is particularly effective to use a copper alloy as the strip.

[For production]

The reason why we set the processing rate during annealing of strips to 40% or more for thick-walled parts and 65% or more for thin-walled parts is that when processing outside this range, processing During subsequent annealing, it is difficult to obtain a uniform state of recrystallization in both thick and thin parts, resulting in variations in properties, deviations in dimensions, or processing defects in subsequent manufacturing processes. is. As a result, not only productivity decreases, but also the value of the product becomes significantly inferior.

In addition, it is desirable for characteristics to perform annealing after processing the irregular cross-section strip within a range that does not coarsen the crystal grain size excessively.
It is preferable to perform annealing in a temperature range of 50°C.

〔Example〕

Next, the present invention will be explained in detail.

Pure copper such as oxygen-free copper and tough pitch copper, 0.1wt% Fe
After melting and casting a copper alloy containing 3n and a trace amount of P and a copper alloy containing 0.15 wt% of 3n and a trace amount of P, hot and cold processing was performed to produce strips of each material. These annealed strips were used as raw materials, and each material was processed under the conditions shown in Table 1 to form the shape shown in Figure 1, with the thick part having a thickness of 1.3M and the thin part having a thickness of 0.5M. A 4# irregular cross-section strip was created and used as a test material. In other words, the processing conditions of the rolling method specified by the method of the present invention (method of the present invention and method B of the present invention)
) and the rolling ratio of the thick part was less than 40%. The materials are represented by symbols a, b, C, and d as shown in Table 1.

Using this sample material, heat resistance, tensile strength, surface gloss, and crystalline state during annealing immediately after processing into irregular cross-section strips were investigated. The results are shown in Table 2.

Regarding heat resistance, the test material was heat-treated at 400°C for 3 minutes in a nitrate bath, and then the Vickers hardness was measured under a load of 500.
9, both the thick and thin parts were measured.

For tensile strength, cut out the thick and thin parts,
A tensile test piece of No. 13 B specified in JIS-72201 was prepared, and the tensile strength was determined based on JIS-72241.

Next, regarding uneven gloss on the surface, visually observe the sample material and mark it as "○" if there is no uneven gloss in thick or thin parts.
Those that are present are marked with an “×”.

The crystalline state after annealing is observed using a metallurgical microscope with a magnification of 75 times, and the recrystallized structure is marked "Q", the case where the recrystallized structure and processed structure are mixed is "Δ", and the processed structure is marked " It was evaluated as "x".

As is clear from Table 2, the irregular cross-section strip produced by the method of the present invention suffers from heat resistance and tensile strength, and the difference between the thick and thin parts is extremely small and is highly uniform.

Further, according to the method of the present invention, the gloss was good, the crystal state was uniform, and no defects in dimensional accuracy occurred. On the other hand, the conventional method has non-uniform properties between thick and thin parts, resulting in poor heat resistance, uneven gloss, etc.

[Effects of the Invention] As described above, according to the method of the present invention, it is possible to easily manufacture irregular cross-section strips having uniform and excellent characteristics in thick parts and inside the board, and for example, in semiconductor lead frames (particularly in power systems). It has remarkable industrial effects, such as providing high reliability as electronic/electrical equipment parts such as lead materials for run sisters), contact base materials, and heat sinks.

[Brief explanation of the drawing]

FIG. 1 is an external view showing the irregular cross-sectional strip. 1...Convex cross-section strip 2... Thick wall part 3... Thin wall part Figure 1

Claims (2)

[Claims] (1) In a method of manufacturing a strip with an irregular cross section in which a thick part and a thin part are integrally formed in the width direction by rolling a strip, after annealing the strip, the thick part is 40% or more and the thin part is 40% or more. 1. A method for manufacturing a strip of irregular cross-section, which comprises rolling at a processing rate of 65% or more, and then further rolling or rolling and annealing one or more times. (2) A method for manufacturing a strip of irregular cross section according to claim 1, in which a copper alloy is used as the strip.