JPS62279015A - Drawing method for wire rod - Google Patents

Abstract

PURPOSE:To equalize the product quality and to reduce the manufacturing cost by applying a mechanical surface roughening treatment to a wire rod whose surface is peeled or cut. CONSTITUTION:A straightener 3, peeling die, 4 honing treatment chamber 5 are installed between a supply 1 and winder 2 to form an inline constitution. Abraseves and water are blasted on a wire rod peeled at a speed of about 90-120 m/min with air by using a gun 6 in the chamber 5. In that time, the size of the abrasives are about 60-120# and an air pressure is set to about 3-5kg/cm<2>. Instead of use of the chamber 5, a shot blast treatment ina shot blast chamber 8 is also available. The surface state after the treatment is equalized due to the mechamical peeling treatment. In that nethod, the quality of drawn wire stocks are equalized and the manufacturing cost is reduced because a heat treatment furnace and pickling device, etc. are eliminative.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the production of wire rods, and particularly to a method of drawing a wire rod whose surface has been scraped or cut.

(Prior Art and Problems) Wire rods manufactured by hot rolling or the like have scratches on their surfaces, so they are cut with a peeling die or the like to remove surface scratches. However, the surface roughness of the wire rod surface after this skin shaving treatment is too smooth with a surface roughness of 1 to 3 μm, and therefore, in the subsequent coating treatment, the coating has poor adhesion and poor adhesion. Therefore, there is a problem that wire drawability and workability of headers etc. deteriorate in subsequent processing steps.

Therefore, conventionally, after skin shaving treatment, skin roughening treatment was performed by (a) heat treatment to generate scale on the surface and then pickling to remove the scale, or (b) pickling alone. , a wire surface with appropriate surface roughness was obtained, and wire drawability was improved.

That is, as shown in FIG. 4, the wire supplied from the supply 1 passes through a straightening machine 3, is skinned by a peeling die 4, and is wound into a coil by a winding machine 2.

Next, this coil is placed in a heat treatment furnace 9 for skin roughening treatment.
The sample is charged into a pickling bath 10 to remove scale. However, in such a skin roughening treatment, the surface roughness is non-uniform, and in particular, when the coil is heat-treated in the form of a coil, there are many variations in the surface roughness at the tip, center, and end of the coil.

In addition, each of the above-mentioned processes of skin shaving or cutting, heat treatment, and pickling have different processing speeds, so it is necessary to process them all in batches, and furthermore, special equipment such as a heat treatment furnace is required, which is inefficient and increases costs. It was bringing about.

(Objective of the Invention) The present invention solves the drawbacks of the above-mentioned prior art, and enables the surface roughening treatment that is actually performed after scraping or cutting the wire rod to be performed at low cost without impairing wire drawability and processability. The object of the present invention is to provide a method that can be easily carried out and can control the surface roughness to a uniform and appropriate value over the entire length.

(Structure of the Invention) The present invention makes it possible to achieve the above object by using mechanical skin smoothing means instead of chemical treatment methods such as heat treatment and pickling, which are difficult to control and expensive. This is what I did.

The present invention will be explained in detail below based on examples.

As mentioned above, the surface of a wire rod that has been skinned to remove surface flaws is extremely smooth with a surface roughness of approximately 1 to 3 μm. The glue is poor and seizure occurs during wire drawing.
It is not possible to increase the wire drawing speed.

For this reason, it is necessary to perform a surface roughening treatment after shaving the skin, but if the surface skin roughening treatment is performed by heat treatment and pickling while the coil is still in use, the surface condition will be such that the skin becomes uneven over 30 to 70% of the total surface area. The roughness also varies over a wide range from 4 to 12 μm at the tip, center, and rear end of the wire coil.
There will be unevenness in the overall length.

According to the research of the present inventor, the cause of this is heat treatment.
This is thought to be because the pickling process itself is a treatment method that makes it difficult to control surface roughness, and moreover, the wire rods are processed in batches in a coiled form.

Therefore, in the present invention, the wire material to be treated is put in a non-coiled state and subjected to the same conditions over its entire length, and the surface roughening treatment is performed by a mechanical method that is easy to control.

Mechanical methods include honing treatment, shot blasting treatment, wire brushing treatment, etc., and desired surface roughness can be obtained by appropriately selecting treatment conditions for each treatment.

For example, in the case of honing processing, as illustrated in FIG. A gun 6 is used to sharpen the wire material and spray water with air onto the wire material whose skin has been shaved at a speed of about 100 mL.

Of course, the type of grinding is not limited, and the number and arrangement of the guns 6 are not limited to those shown.

The honing treatment conditions can be determined depending on the material of the wire, the degree of surface roughness, etc. For example, in the case of 5US304 stainless steel, as shown in Table 1, various surface roughnesses can be obtained depending on the combination of the abrasive grain size and air pressure used, and the surface roughness increases as the abrasive grain size increases. Also, the larger the air pressure, the larger the value. In addition, grinding is from #60
The air pressure is preferably about #120 and about 3 to 5 kg/ai, and in consideration of the cost of the air source, it is desirable to use a low air pressure.

Table 1: Surface roughness (μm) The die 4 and the shot blast processing chamber 7 are arranged in-line, and the shot supplied to the impeller 8 is projected onto the shaved wire. As with the honing process,
There are no restrictions on the type of shot, the number of impellers,
There are no restrictions on placement either.

The shot blasting conditions can be determined depending on the material of the wire, the degree of surface roughness, etc. For example, SUS
In the case of materials such as 310 stainless steel, various surface roughnesses can be obtained depending on the combination of shot size and projection speed, as shown in Table 2. In addition, the size of the shot is 0.2 to 0.
．． 6 mm, and the projection speed is preferably about 30 to Loom/s.

(Note) Type of shot: cut wire If the honing process and shot blasting process described above are performed in-line as shown in the figure, the cost can be reduced to about 1/3 to 1/7 compared to when they are performed offline.

Of course, it goes without saying that the same applies to wire brushing treatments and the like.

The surface roughness obtained by the above-mentioned mechanical surface roughening treatment needs to be determined from the relationship of wire drawability and workability of headers, etc. The present inventor investigated the relationship between surface roughness and wire drawability for wire rods made of various materials.

For example, 5US304 stainless steel wire is honed or shot blasted to give various levels of surface roughness, and the diameter is changed from 5.5 mm to 2.0 mm.
The maximum wire drawing speed that can be drawn without burning during continuous drawing was investigated. As shown in Figure 3, the surface roughness was 10 μm.
If it is above, the maximum wire drawing speed will be 200 m/lll1n or more, and the wire drawability will be improved.

Similar results were obtained for wire rods made of other materials, and from these results, it is necessary to have a surface roughness of 10 μm or more in order to improve wire drawability. However, if the surface roughness is too large, the surface after wire drawing will Since gloss cannot be obtained, it is desirable that the thickness be 20 μm or less.

(Example) After SUS304 (18-8 stainless steel) wire rods were skinned using a peeling die, the following different surface roughening treatments were performed on each wire rod.

The conventional method is to heat treat the coil as it is (solution treatment).
A pickling treatment is carried out, and the method of the present invention is a continuous honing treatment [grinding (alundum) #100, air pressure 3 k
g/all (Example 1); Grinding (alundum) #10
0, air pressure 4 kg/# (Example 2)] and shot blasting [shot (cut wire) 0.4 w+
m, and the projection speed was 40+/sl (Example 3).

When we investigated the surface roughness of the wire obtained by surface roughening treatment, we found that the surface roughness of the wire rod obtained by the conventional method was 4 to 12 μm.
m, and the roughness was greater at the center and end portions than at the tip of the coil, and the skin had an uneven surface condition with skin abnormalities occurring over the entire length. All of the specimens had good surface conditions with uniformly rough skin over the entire length, and the surface roughness was 11 to 13 μm (Example 1), 10 to 13 μm (Example 2), and 11 to 1 μm.
It was controlled within a narrow range of 4 μm (Example 3).

Next, after coating these wires, they were drawn using an 8-drawer. During wire drawing, the wire drawing speed was gradually increased while checking the wire drawing situation, and the wire drawing speed (maximum wire drawing speed) at which the wire could be drawn without problems such as seizure and wire breakage was determined. As a result, the maximum wire drawing speed of the wire rod according to the conventional method was 180 m/lll1n, whereas in the example 1
205m/min in Example 2, 210n/win in Example 2
In Example 3, it was 230 m/win, and the wire drawability was improved.

(Effects of the Invention) As detailed above, according to the present invention, the surface roughening treatment performed after scraping or cutting includes honing treatment,
Since mechanical treatments such as shot blasting and wire brushing are applied, the desired surface roughness can be easily obtained, and the surface can be evenly roughened over the entire length. Furthermore, the mechanical treatment method described above is easy to control since it is only necessary to appropriately determine the treatment conditions, and there is no need to use a heat treatment furnace or pickling equipment as in the conventional method, resulting in a significant cost reduction. Of course, it is clear that the effect will be even greater if the process is carried out in-line with the peeling or cutting operation, and in addition, the wire drawing process can also be carried out in-line.

[Brief explanation of the drawing]

FIGS. 1 and 2 show examples of the arrangement of equipment for in-line carrying out the method of the present invention, with FIG. 1 showing the case of honing processing and FIG. 2 showing the case of shot blasting processing. FIG. 3 is a diagram showing the relationship between the surface roughness obtained by mechanical surface roughening treatment and the maximum wire drawing speed (wire drawability). FIG. 4 is a diagram showing a processing line implementing the conventional method. 1... Supply, 2... Winder, 3.
... straightening machine, 4 ... peeling die, 5
...Honing treatment chamber, 6.Gun, 7.Shot blasting chamber, 8.Impeller, 9.Heat treatment furnace, 10.
... Pickling tank. Patent applicant: Daido Steel Co., Ltd. Patent attorney Hisashi Nakamura Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A method for drawing a wire rod, which comprises performing mechanical surface roughening treatment on the wire rod when drawing the wire rod whose surface has been shaved or cut. (2) The method according to claim (1), wherein the skin shaving or cutting and mechanical surface roughening treatment are carried out in-line.