JPH04311552A - Production of copper coated steel wire - Google Patents

Abstract

PURPOSE:To offer a method for manufacturing a copper coated steel wire capable of manufacturing a copper coated steel wire having high strength while the wear of a die grinding the surface layer part of a steel wire to form a core wire is suppressed in a method for manufacturing a copper coated steel wire by a dip forming method. CONSTITUTION:At first, the surface layer part of a steel wire contg., by weight, >0.1 to 0.50% carbon and 0.025 to 0.070% sulfur is ground by a die. Next, this steel wire is immersed into the molten metal of copper or a copper alloy to stick the copper or copper alloy to the surrounding of the steel wire.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing copper-coated steel wire by the dip forming method, and in particular to a copper-coated steel wire with improved die life by improving the grindability of the steel wire used as a core material. Relating to a manufacturing method.

0002

[Prior Art] Conventionally, in a method for manufacturing copper-coated steel wire by the so-called dip forming method in which the core material is immersed in molten metal and the coating material is attached, first, the surface of the steel wire that will become the core wire is peeled and then a die or the like is used. to make the surface metallurgically clean. Thereafter, the steel wire is continuously immersed in a molten copper or copper alloy to adhere the copper or copper alloy to the surface of the steel wire and solidify it. Thereby, it is possible to obtain a copper-coated steel wire in which the steel and the copper or copper alloy are sufficiently bonded at the interface between the steel wire and the copper or copper alloy portion.

[0003] It should be noted that copper-coated steel wire has a higher tensile strength when the carbon content of the core steel wire is higher at the same processing rate. When strength is required, high-strength steel wire with a carbon content of more than 0.1% by weight is used as the core material.

0004

[Problem to be Solved by the Invention] However, if the wire diameter and wire speed of the steel wire to be processed are the same, the higher the carbon content of the steel wire, the higher the hardness of the steel wire. The life of the peeling die used in the steel wire surface cleaning process is shortened when manufacturing high-strength copper-coated steel wire. That is, when a steel wire is used as the core material, a large force is applied to the cutting edge of the peeling die during the surface cleaning process, and frictional heat is generated around the cutting edge. While this process is carried out continuously for a long time, the cutting edge of the die gradually wears down, and eventually a part of the steel wire is left uncoated and the copper is not coated in this part. . In this case, it becomes impossible to manufacture copper-coated steel wire, and it becomes necessary to stop manufacturing and replace the die. In this case, there is a problem that the higher the carbon content of the steel wire, the harder the steel wire must be peeled, which shortens the life of the die. Furthermore, since the die must be replaced frequently, there is also the problem that manufacturing costs are high.

[0005] Therefore, in order to manufacture copper-coated steel wire using an actual peeling die in an industrial production process, the carbon content of the steel wire must be limited to 0.35% by weight or less. There is also the problem of not being able to get it.

The present invention has been made in view of these problems, and provides a method for producing copper-coated steel wires that can continuously produce high-strength copper-coated steel wires over a long period of time and at low cost. The purpose is to provide a method.

[0007]

[Means for Solving the Problems] The method for producing a copper-coated steel wire according to the present invention includes a copper-coated steel wire containing 0.1 to 0.50% by weight of carbon (excluding 0.1% by weight) and 0% of sulfur.
．． A step of grinding the surface layer of the steel wire containing 0.025 to 0.070% by weight using a die, and immersing the steel wire in molten copper or copper alloy to adhere copper or copper alloy around the steel wire. It is characterized by having a process.

[0008]

[Operation] In the present invention, carbon is 0.1 to 0.5
The surface of a steel wire containing 0% by weight (but not including 0.1% by weight) and 0.025 to 0.070% by weight of sulfur is ground with a die to be peeled. In this way, by incorporating sulfur into the steel wire, the grindability of the steel wire can be improved. In other words, in the present invention, since it is only necessary to grind the surface layer of the steel wire whose grindability has been improved by incorporating a predetermined amount of sulfur, the force applied to the die is significantly reduced compared to the conventional method. . Thereby, the life of the cutting edge of the die can be extended, and surface grinding and dip forming of the steel wire can be performed continuously over a long period of time.

Furthermore, since the steel wire used in the present invention has a relatively high carbon content of more than 0.1% by weight and less than 0.50% by weight, the steel wire itself has high strength. In the present invention,
After cleaning the surface layer of the steel wire, which has a relatively high carbon content, by grinding, the steel wire is coated with copper or copper alloy by dip forming, and then, for example, the copper-coated steel wire is subjected to wire drawing. give Thereby, a high-strength copper-coated steel wire can be obtained.

Next, the reason for limiting the sulfur content and carbon content of the steel wire serving as the core material will be explained.

[0011] If the sulfur content is less than 0.025% by weight, the effect of improving the grindability of steel wire will not be sufficient. That is, if a steel wire with a sulfur content of less than 0.025% by weight and a carbon content of more than 0.1% by weight is used, a steel wire with a carbon content of 0.1% by weight or less is used. The lifespan of the die will be significantly shortened compared to the normal case. For this reason, the sulfur content of the steel wire is set to 0.025% by weight or more. This improves the grindability of steel wire,
Dice life can be extended. On the other hand, when the sulfur content exceeds 0.070% by weight, wire drawability decreases.

[0012] Steel wire specified in JIS G 4804 includes free-cutting steel containing 0.08 to 0.40% by weight of sulfur, and free-cutting steel containing 0.08 to 0.40% by weight of sulfur and lead. There are composite free-cutting steels containing 0.10 to 0.35% by weight. However, when these free-cutting steels or composite free-cutting steels are used as copper-coated steel wires, the wire drawability is not satisfactory, and the desired area reduction ratio cannot be obtained during wire drawing.

Therefore, in the present invention, the sulfur content is set to 0.025% by weight to 0.070% by weight as a range that can improve the grindability while not impairing the wire drawability.

[0014] If the carbon content is less than 0.1% by weight, the desired strength cannot be obtained. On the other hand, if the carbon content exceeds 0.50% by weight, sufficient grindability cannot be obtained even if 0.070% by weight of sulfur is contained. Therefore,
Carbon content is 0.1 to 0.50% by weight (however,
(excluding 0.1% by weight).

[0015]

[Example] Next, an example in which a copper-coated steel wire was actually manufactured by the method of the present invention and a comparative example thereof will be described.

Example 1 First, J was used except that the sulfur content was 0.070% by weight.
It has the same composition as IS SWRCH20K (however, the carbon content is 0.18 to 0.23% by weight) and the diameter is 1.
A 0 mm steel wire was prepared as a core material, and the surface layer of this steel wire was ground using a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method, and the electrical conductivity is increased to 30.
% IACS (electrical conductivity when the electric conductivity of pure copper annealed material is set to 100) was obtained. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

Example 2 First, a JIS SWRM 12 steel wire with a sulfur content of 0.025% by weight and a diameter of 15 mm (however, the carbon content was more than 0.10% by weight and less than 0.15% by weight). was prepared as a core material, and the surface layer of this steel wire was ground using a die. Next, the peripheral surface of this steel wire was coated with copper by a dip forming method to obtain a copper-coated steel wire with an electrical conductivity of 40% IACS. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

Example 3 First, J was used except that the sulfur content was 0.070% by weight.
It has the same composition as IS SWRCH50K (however, the carbon content is 0.47 to 0.50% by weight) and the diameter is 1.
A 5 mm steel wire was prepared as a core material, and the surface layer of this steel wire was ground using a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method, and the conductivity is increased to 60%.
%IACS copper coated steel wire was obtained. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

Comparative Example 1 First, a steel wire similar to Example 1 except that the sulfur content of the steel wire was 0.20% by weight was prepared, and the surface layer of this steel wire was ground using a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method, and the conductivity is increased to 3.
A copper coated steel wire with 0% IACS was obtained.

Comparative Example 2 First, the same steel wire as in Example 1 was used except that the sulfur content of the steel wire was 0.28% by weight, and the surface layer of this steel wire was ground with a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method, and the conductivity is increased to 3.
A copper coated steel wire with 0% IACS was obtained. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

Comparative Example 3 First, a steel wire similar to that of Example 3 except that the sulfur content of the steel wire was 0.08% by weight was prepared, and the surface layer of this steel wire was ground using a die. Next, by dip forming, the circumferential surface of this steel wire is coated with copper, and the conductivity is increased to 6.
A copper coated steel wire with 0% IACS was obtained. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

Comparative Example 4 First, the sulfur content was 0.070.
JIS SWRH 57A except for weight% (however,
A steel wire with a diameter of 10 mm and having the same composition (carbon content: 0.54 to 0.61% by weight) was prepared as a core material, and the surface layer of this steel wire was ground using a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method.
A copper-coated steel wire with a conductivity of 30% IACS was obtained.

Comparative Example 5 First, a steel wire having a carbon content of 0.1% by weight and a sulfur content of 0.02% by weight was prepared, and the surface layer of this steel wire was ground using a die. Next, the circumferential surface of this steel wire is coated with copper using the dip forming method, and the electrical conductivity is increased to 40.
%IACS copper coated steel wire was obtained. Thereafter, this copper-coated steel wire was subjected to a wire drawing process.

[0024] The steel wire skin remained in a healthy state for more than 12 hours in a continuous manner in Example 1, for more than 20 hours in Example 2, and for more than 10 hours in Example 3. We were able to continue peeling. In addition, in these Examples 1 to 3, copper-coated steel wires can be smoothly manufactured, and even in the post-process wire drawing process, no inconvenience occurs, and high-strength copper-coated steel wires can be produced. was able to manufacture.

On the other hand, in Comparative Example 1, the peeling condition of the steel wire deteriorated after only 2 hours, and it was not possible to continue manufacturing the copper-coated steel wire any further. Further, in Comparative Examples 2 and 3, as in Examples 1 to 3, sound steel wire peeling could be carried out for more than 10 hours, and copper-coated steel wires could be obtained. However, in the wire drawing process, the wire could not be processed at the desired area reduction rate, and wire breakage occurred.

Furthermore, in Comparative Example 4, the peeling condition of the steel wire deteriorated after only about 3 hours, and it was not possible to continue manufacturing the copper-coated steel wire any further. Furthermore, in Comparative Example 5, although the copper-coated steel wire was successfully manufactured, the strength of the core material itself was low, so even when the wire was drawn to the processing limit, the ASTM (Ame
rican Society for Testing
It was not possible to obtain the desired high-strength copper-coated steel wire described in the andMaterial) standards.

[0027]

Effects of the Invention As explained above, according to the method of the present invention, copper-coated steel wire is manufactured using steel wire containing a predetermined amount of sulfur and carbon, so there is less wear and tear on the cutting edge of the die, and the method lasts for a long time. It is possible to continuously produce high-strength copper-coated steel wire over a period of time. As a result, the frequency of die replacement can be reduced compared to the conventional method, thereby reducing the manufacturing cost of the copper-coated steel wire.

Claims (1)

[Claims] [Claim 1] 0.1 to 0.50% by weight of carbon (
However, it contains sulfur (excluding 0.1% by weight) and sulfur.
A step of grinding the surface layer of the steel wire containing 0.025 to 0.070% by weight with a die, and immersing the steel wire in molten copper or copper alloy to coat the periphery of the steel wire with copper or copper alloy. 1. A method for manufacturing a copper-coated steel wire, comprising the step of adhering the wire.