JPS58138511A - Production of metallic wire - Google Patents

Abstract

PURPOSE:To produce a metallic wire having good quality without any crack at a relatively high drawing rate by drawing a tungsten wire at the drawing temp. higher than the transition temp. thereof by using a die having a reduction angle in a specific range. CONSTITUTION:In the stage of drawing a tungsten wire by using a cemented carbide die or diamond die constituting of an introducing part 1, a restricting part 2, a reduction part 3, a bearing part 4, a relief part 5, etc., the wire is drawn in a 12-16 deg. range of the reduction angle theta of said die, and in a 20-40% drawing rate per time of the above-mentioned wire to be drawn, that is, at the drawing temp. higher than the transition temp. of the tungsten wire, whereby the tungsten wire of high quality is produced economically at a high drawing rate without generating cracks.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metal wire, and particularly to a method for drawing a tungsten wire.

Generally when drawing tungsten wire.

Wire drawing is performed using a carbide die or a diamond die. When line drawing is performed, ideally the first
As shown in Figure (a), the trajectories drawn by the line-drawing start point X and the line-drawing end point Y are parallel to each other.

Moreover, the processing area indicated by diagonal lines has a truncated conical shape. However, in reality, as shown in FIG. 1(b), the trajectory of the starting point X' and the ending point Y' often curves in a V-shape. When this degree of curvature is large, a large difference in deformation occurs between the outside and the center of the material. Specifically, the outside of the material experiences the most shear deformation, while the center experiences no deformation. For this reason, a difference in residual strain occurs between the center and the outside, making it easier for cracks to occur.

Here, the above-mentioned degree of curvature varies depending on the reduction angle of the die, and the larger the reduction angle of the die, the greater the degree of curvature. Furthermore, the smaller the reduction angle of the die, the easier it is to polish and the shorter the life span, so making the reduction angle smaller is disadvantageous from an economic point of view.

Further, the higher the drawing rate per one time, the smaller the above-mentioned degree of curvature becomes, so it is desirable that the drawing rate is larger.

However, when drawing a tungsten wire, the deformation resistance increases at the starting point X and ending point Y as shown in FIG. 1(e), so brittle fracture occurs at room temperature and drawing cannot be performed. Therefore, unless the tungsten wire is processed at a processing temperature higher than the transition temperature at which it transitions from a brittle region to a ductile region, wire breakage or cracks will occur.

Conventionally, as a method of drawing tungsten wire.

A method has been proposed in which the reduction angle of the die is selected between 5 degrees and 17 degrees, and the drawing rate (area reduction rate) is selected from 3 inches to 30%. (Special Public Interest Publication No. 54-40459
Although this method has no problem in terms of the mection angle of the die, it is insufficient in terms of the wire drawing rate, and therefore has the disadvantage of a large degree of curvature.

The purpose of the present invention is to achieve a wire drawing rate of 30% or more.

An object of the present invention is to provide a method for manufacturing a metal wire that can be drawn without causing cracks.

Another object of the present invention is to provide an economical method for manufacturing tungsten wire that can yield high quality tungsten wire.

Referring to FIG. 2, two carbide dies or diamond dies used in the present invention have an introduction part 1. Aperture part 2. Reduction part 3. Bearing part 4. The tungsten wire to be drawn is guided from above the introduction part 1.

Each part of the die has the shape of a rotating body having the same central axis. Here, fern 22. The angle θ formed by the opposing inner walls of the flap portion 3 is a reduction angle.

Examples of the present invention will be described below.

For example, a tungsten wire with a diameter of 5.31 ml has a diameter of 4.2 am with an area reduction rate of 32-37%.

When drawing 3.4III+ or 2.811I+ with a die, the reduction angle and transition temperature of the die used (processing temperature within the reduction part of the die)
The crack occurrence rate by changing is as follows. Line heating temperature 95
It was 0-100°C.

Table 1 (Temperature inside the reduction section 350℃~3
75℃) Die reduction angle Wire crack occurrence rate 8 degrees O/ Book 12 # O/1214'#
0/1216I O/
12 20I 6/12 Crack rate when the temperature inside the reduction part is 300 to 325°C as shown in Table 2. Line heating temperature 950℃~1000℃
It was ℃.

Table 2 (Temperature inside the reduction part 300-325
°C) Reduction angle of die Wire crack occurrence rate 8 degrees 8/12 121 9/1214″
8/1゜161
10/1220' 12/12
The length of each wire is 50 m. □Again. Diameter 5.
Table 3 shows the crack occurrence rate when the reduction angle was changed by drawing with a reduction of area of 10 inches from 3a. The wire heating temperature was 950 to 1000°C.

Table 3 (Temperature inside the reduction part 350-375
°C) Reduction angle of die Wire crack occurrence rate 8 degrees 5/12 12I 6/12 14・ 8/1゜16I
9/12 20' 12/12 In either case, the length of one wire is 50m and there are four wires.

Also, when reducing the diameter to 2.2 am, 1.711 I, l, 31 m as the area reduction rate of 38 to 42 inches (diameter 2.8 ms).

When the following types of dies were used with different reduction angles, the cracks generated in the tungsten wire were 0-wire heating temperatures of 950 to 1000°C, as shown in Table 4.

Table 4 (Temperature inside the reduction part 350-375
°C) Reduction angle of die Wire crack occurrence rate 8 degrees O/12 12# 0/, 214#
O/1216s
O/1220# 8/12 In either case, the length of one wire is 100 m.

Table 5 shows the occurrence rate of cracks when the internal temperature of the reduction section is 300 to 325°C. Line heating temperature is 950-100
It was 0°C.

Table 5 (Temperature inside the reduction part 300-325
°C) Die reduction angle Wire crack occurrence rate 8 degrees 7/1°12”/12 141 10/1216#
8/1220#
12/12 In both cases, the length of one wire was 100 m. Also, when drawing from a diameter of 2.8 M with an area reduction rate of 10%, the crack occurrence rate when changing the reduction angle is shown in Table 6. there were. The wire heating temperature was 950-1000°C.

Table 6 (Temperature inside the reduction part 350-375
℃) Reduction angle of die Wire crack occurrence rate 8 degrees 6/□2 12# 10/1214 p
”'12/1216#
12/1220〃 12/
12 In either case, the length of one line is 100 m.

When the reduction angle of the die exceeds 20 degrees, the rate of crack occurrence increases rapidly.

Further, if the processing temperature in the reduction part is 350° C. or lower, the incidence of cracks will increase.

If the area reduction rate exceeds 45%, the wire will break regardless of the reduction angle.

Figure 3 shows the above results in a correlation characteristic curve diagram, where the horizontal axis represents the reduction angle of the die and the vertical axis represents the area reduction rate of the tungsten wire at a processing temperature of 350 to 375°C in the reduction section. .

In the figure, cracks do not occur in the area surrounded by the ABEF rectangle, but as mentioned above, if the reduction angle of the die is small, the life will be shortened.

This range is not very desirable. Therefore, ABCD in Figure 9
The range surrounded by the rectangle is good.

As for the thickness of the wire, it is appropriate to draw the wire with a thickness of 500 μφ or more. As explained above, when tungsten wire is drawn by drawing using a die, the area reduction rate of the wire and the reduction angle of the die.

By keeping the transition temperature (processing temperature in the reduction part) within the above range, it is possible to obtain a high-quality tungsten wire that does not easily cause wrinkle wire cracks.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a deformed band caused by drawing, Fig. 2 is a cross-sectional view showing an outline of a die used for drawing tungsten wire, and Fig. 3 shows the area reduction ratio of tungsten wire and the reduction of the die. FIG. 4 is a characteristic curve diagram showing the relationship with the angle. Explanation of symbols = 1 is the introduction part of the die, 2 is the drawing part of the die, 3 is the reduction part of the die, 4 is the bearing part of the die, 5 is the escape part of the die, and θ is the reduction angle of the die. ing. 51

Claims (1)

[Claims] 1. When drawing tungsten wire using a die, the reduction angle of the die used is 12° to 16°.
The wire is drawn at a drawing temperature of 20 cm to 45%, and the wire drawing temperature is equal to or higher than the transition temperature of tungsten wire. Method of manufacturing wire.