JPH049454A - Manufacturing method for high-strength, high-conductivity copper alloy fine wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a high-strength, high-conductivity copper alloy fine wire that has excellent mechanical properties and conductivity and is used as lead wires for electronic components.

[Conventional technology]

Lead wires and the like of electronic components are subjected to repeated stretching and bending, and therefore require good mechanical properties.

On the other hand, conductivity as a current-carrying component is also required. In this way, lead wires, etc. are required to have high strength and high conductivity, but in order to satisfy both of these characteristics, at least C is added as an additive element.
Cu-Cr alloys containing r are known. By precipitating and dispersing Cr@copper, this alloy improves its mechanical properties and maintains the high electrical conductivity inherent in copper.

A method for manufacturing thin copper wires such as lead wires (for example, diameter 0.08 am+) from this type of Cu-C+ alloy is as follows. First, an ingot adjusted to have a predetermined composition is cast. This ingot is cut, surface-finished, molded at about 900° C., and water-cooled to obtain rough drawn wire (for example, diameter 11 wm). Next, this roughly drawn wire is subjected to cold wire drawing to obtain a thin wire with a predetermined final wire diameter, and then heat treated (hereinafter referred to as final heat treatment) to obtain a predetermined high-strength, high-conductivity copper alloy thin wire. be.

(Problem to be Solved by the Invention) The characteristics of a rough drawn wire made of this type of Cu-Cr alloy that was cold drawn and subjected to final heat treatment will be explained with reference to FIG. FIG. 2 shows the tendency of mechanical properties such as tensile strength and conductivity with respect to final heat treatment temperature and additive elements I such as Cr. As is clear from FIG. 2, as the amount of added elements increases, the tensile strength improves, but the electrical conductivity decreases. Furthermore, as the final heat treatment temperature increases, the electrical conductivity improves, but the tensile strength decreases. Thus, tensile strength and electrical conductivity are contradictory properties. Therefore, by adjusting the composition of the copper alloy and selecting the final heat treatment temperature, the mechanical properties and electrical conductivity are set to predetermined values, but there are limits.8For example, when cables for industrial robots require bending resistance, The problem with cable conductors is that mechanical properties tend to be emphasized, and if anything, conductivity is sacrificed to some extent.

The present invention has been made in view of the problems of the conventional technology, and its purpose is to provide a high-strength, high-conductivity copper alloy fine wire with excellent mechanical properties and improved conductivity. The purpose is to teach the manufacturing method of

[Failure to solve the problem]

In order to achieve the above object, the method for producing a high-strength, high-conductivity copper alloy thin wire of the present invention provides a rough drawn wire made of a copper alloy in which the total amount of additive elements containing at least Cr is 0.1 to 2.0% by weight. In the method of obtaining high-strength, high-conductivity copper alloy thin wire by cold drawing, heat treatment is performed at an intermediate wire diameter leading to the final thin wire
After precipitating r, cold drawing is performed until the final wire diameter is fine.

Preferably, the cold-drawn wire with a fine final diameter is subjected to heat treatment.

[Function] In place of the final heat treatment performed after cold wire drawing, the present invention provides
This was based on the finding C: that conductivity is improved without significantly lowering mechanical properties when heat treatment is performed at an intermediate wire diameter during cold wire drawing (hereinafter referred to as intermediate heat treatment). If heat treatment is performed again after the final wire drawing process, variations in mechanical properties and electrical conductivity can be reduced and uniform properties can be obtained. in this way,
The reason why conductivity is improved by performing intermediate heat treatment even if the mechanical properties are almost the same is presumed to be as follows. If only the final wire diameter is heat treated, a considerable amount of unprecipitated Cr still exists in the copper matrix, but if heat treatment is performed with an intermediate wire diameter, the amount of Cr precipitated will increase more. At the same time, processing strain in the copper matrix is also removed, and this is thought to be connected to the improvement in conductivity.

; Examples] Next, the composition of the present invention and the conditions of intermediate heat treatment will be explained, but the present invention is not limited to these Examples. Copper alloy is Cr-based, but other additive elements include Au, Ag, A, I, BBe, Bi, Ca, Cd, and C.
o, Fe, Ge, Tif, In, Mg, Mn, Ni,
One or more types of P, Pb, 5bSi, Sn, Ti, Y, Zn, Zr, and metals (referring to a mixture of rare earth elements mainly including Ca and Ce) can be added. The total amount of these additional elements is 0. If it is less than 0.1% by weight, the mechanical properties will not improve, and if it exceeds 2.0% by weight, the electrical conductivity will decrease. next,
The intermediate heat treatment is preferably carried out at 300°C to 6°OoC. If the temperature is less than 300°C, the mechanical properties are excellent but the conductivity is low; if it exceeds 600°C, the mechanical properties deteriorate and precipitation occurs. The Cr dissolved therein re-dissolves and the conductivity also decreases. Further, the heat treatment time may be at least 1 hour or more as long as uniform heating is ensured. and,
The diameter of the intermediate wire to be subjected to the intermediate heat treatment is preferably determined so that the area reduction rate (%) expressed by the following formula is 5% or more, and more preferably 90% or more.

Intermediate wire diameter cross-sectional area ratio (%) That is, as shown in Part 1, if it is less than 5%, the intermediate heat treatment will be too fast and the mechanical strength will not improve much.

As shown in Figure 1, if we focus on the changes in both properties with respect to the area reduction rate, we find that as the area reduction rate increases, the electrical conductivity tends to decrease less while the mechanical properties improve. The present invention was completed by paying attention to this.

Examples of the present invention will be explained below in comparison with comparative examples.

As shown in Table 1, the total amount of additive elements, mainly Cr and In, is 0. 1% by weight, 0.2% by weight, 1゜5% by weight
For three types of copper alloys, rough wire with a wire diameter of 11 mm is manufactured, and after solution treatment at 950°C for 1 hour, water quenching is performed, and after this, the intermediate wire diameter becomes 95% of the castle area. Cold wire drawing and intermediate heat treatment (500°C
) After that, the wire was cold drawn to a final wire diameter of 0°08mm.

Examples 1 and 2 were each subjected to final heat treatment under the conditions shown in Table 1, and then subjected to sample 7 (example 3 was not subjected to heat treatment). In addition, Comparative Examples 4 to 7 were subjected to cold wire drawing from the rough drawing g (Ibs) described above to a final wire diameter of fine wire (0.08@s), and then subjected to final heat treatment and used as samples. And examples 1 to 3 of the present invention,
Tensile strength and electrical conductivity were measured for Comparative Examples 4 to 7, respectively.

(Left below) As is clear from Table 1, for example, Example 1 is the same as Comparative Example 4.
However, the tensile strength is still comparable to that of
The conductivity has improved by 5%.

〔Effect of the invention〕

The high-strength, high-conductivity copper alloy thin wire produced by the present invention is subjected to intermediate heat treatment during cold wire drawing, and has excellent electrical conductivity while maintaining high mechanical strength. It is possible to make a high-strength, high-conductivity thin copper alloy wire that can withstand harsh usage conditions and has good conductivity, such as lead wires used in robots. When reheating is performed after the cold wire drawing process, the wire is homogenized and a high-strength, high-conductivity copper alloy fine wire with high reliability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a graph showing changes in tensile strength or electrical conductivity with respect to area reduction ratio, and FIG. 2 is a graph showing changes in tensile strength or electrical conductivity with respect to final heat treatment temperature. Patent Applicant Tuck Wire Co., Ltd. Representative Patent Attorney Yoshiyuki Kaji Figure (Capital) Area Reduction Rate] 00 Figure Final Heat Treatment Temperature ("CX3hr)"

Claims (2)

[Claims] (1) The total amount of additive elements including at least Cr is 0.1 to
In a method for obtaining a high-strength, high-conductivity copper alloy fine wire by cold drawing a rough drawn wire made of a copper alloy of 2.0% by weight, heat treatment is performed at an intermediate wire diameter leading to the final wire diameter to precipitate Cr. A method for producing a high-strength, high-conductivity thin copper alloy wire, which comprises cold drawing the wire to a final wire diameter. (2) The method for producing a high-strength, high-conductivity copper alloy thin wire according to claim 1, wherein the cold-drawn final wire diameter thin wire is subjected to heat treatment.