JP2012081502A - Method and device for drawing austenitic stainless steel wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of equipment and stably perform temperature control.SOLUTION: The method for drawing austenitic stainless steel wire includes the steps of: passing an austenitic stainless steel bus line applied with tension through a heated liquid lubricant, and heating the bus line; and drawing the heated bus line.

Description

  The present invention relates to a method and apparatus for drawing austenitic stainless steel wire in which work-induced martensite is generated during processing.

  In wire drawing (drawing) of austenitic stainless steel wire, work-induced martensite is generated during processing. For this reason, hardening due to the generation of work-induced martensite is added together with work hardening due to the proliferation of passive dislocations due to the accumulation of dislocations that normally occurs in metals. As a result, the austenitic stainless steel wire is broken when it is drawn at a high area reduction rate.

  For these reasons, in the conventional wire drawing of austenitic stainless steel wire, when continuously drawing a 5.5 mm bus to a final diameter of 0.34 mm φ, for example, the bus is up to 2.20 mm φ with an area reduction of 84%. After the primary wire drawing, the primary bright annealing is performed to austenite the martensite, then the secondary wire drawing is performed up to 0.89 mmφ at a surface reduction rate of 83.3%, and then the secondary bright annealing, and further up to 0.34 mmφ at 85.6%. It is drawn. That is, in the conventional method, it is necessary to arrange three kinds of wire drawing machines, and it is necessary to perform bright annealing twice. For this reason, there is a problem that equipment costs are required.

  In order to solve this problem, Patent Document 1 arranges induction heaters in front of dies or die rollers arranged in a row, and inductively heats the bus bar with induction heaters, and then sequentially passes the dies or die rollers to wire drawing. Proposes to process.

Japanese Patent Publication No. 7-80008

  However, in this method, since the induction heaters must be arranged in front of the dice or the dice roller, the problem of increased equipment costs is not necessarily solved. In addition, when the drawing conditions such as the working line speed change, it is necessary to accurately control the processing time of the induction heater and the like so that the desired temperature is reached.

In order to solve the above-described problems, the method of drawing an austenitic stainless steel wire according to the present invention passes the bus bar through an austenitic stainless steel bus wire to which tension is applied in a heated liquid lubricant. A step of heating, a step of drawing the heated busbar,
It comprises.

  Since the austenitic stainless steel wire is heated with a lubricant, the present invention does not incur equipment costs, and has an effect that temperature control can be performed stably even if the wire drawing conditions are changed.

It is the schematic of the wire drawing processing apparatus of the austenitic stainless steel wire for demonstrating the principle of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  The apparatus shown in FIG. 1 includes a back tension roller 10 (tension applying means) that applies back tension to the austenitic stainless steel bus W to be drawn. On the downstream side of the back tension roller 10, a die container 20 is arranged, and a die 30 (drawing means) for drawing the austenitic stainless steel bus W is arranged at the subsequent stage of the die container. The die containing body 20 is supplied with a heated lubricant, and is heated when the austenitic stainless steel bus passes therethrough. The die container 20 is connected to the lubricant tank 40 via a lubricant supply pipe 44, a circulation pump 46, and a return pipe 48 that constitute a circulation path for circulating the lubricant. The lubricant tank 40 stores heated lubricant, and the heated lubricant circulates between the lubricant tank 40 and the die container 20. The lubricant tank 40 is provided with a heater 42 (heating means) for heating the lubricant in the lubricant tank and a temperature detecting means (thermometer 50) for detecting the temperature of the lubricant, and the heating temperature of the lubricant is a predetermined temperature. The temperature is controlled.

  Thus, the austenitic stainless steel bus W passes through the die container 20 in a state where tension is applied, and is drawn by the die 30.

  A heated lubricant is supplied into the die housing 20, the bus W is heated to a predetermined temperature when passing through the die housing, and the bus W is pulled out at a predetermined area reduction rate while being heated. Processed. The lubricant tank 40 supplies the heated lubricant to the die container 20, the lubricant stored therein is heated to a predetermined temperature by the heater 42, and the heated lubricant is supplied to the lubricant supply pipe 44. The lubricant in the die housing is returned to the lubricant tank 40 by a return pipe 48. The temperature of the lubricant is sequentially detected by a temperature detecting means (thermometer 50) so that the lubricant is maintained at a desired temperature.

  In this example, a back tension roller is used as the tension applying means, but known tension applying means such as vertical and horizontal rollers can also be used. The reason for applying the back tension is to make the processing uniform and easy by putting the wire straight into the die.

  As the lubricant, either a water-soluble lubricant or an oil-based lubricant can be used. In the case of a water-soluble lubricant, the heating temperature exceeds normal temperature and is less than 100 ° C. In the case of an oil-based lubricant, the heating temperature is 100 ° C. or higher and 250 ° C. or lower.

  Any known lubricant can be applied as the lubricant, and examples of the water-soluble lubricant include Ratple NN-21 (manufactured by Nisshin Chemical Laboratory Co., Ltd.). Examples of the oil-based lubricant include PZ-1105 ( Japan UNESCO Corporation).

  In the above example, the bus W is immersed and heated in the lubricant, but it is also possible to heat the bus W by spraying the lubricant.

  Although the principle of the present invention has been described with reference to FIG. 1, this principle can be applied to various wire drawing apparatuses. For example, the present invention can be applied to a so-called slip-type wire drawing apparatus in which a plurality of dies are sequentially arranged in the die housing 20 and the wire drawing is sequentially performed. Further, it is possible to adopt a system in which the lubricant is circulated and supplied from a single lubricant tank to a plurality of or all of the die containers. In addition, when applied to a fully immersed or shower type corrugated wire drawing device, the lubricant in one lubricant tank is heated and the heated lubricant is supplied to the die container that accommodates the corrugated vehicle.・ Can circulate.

  In any case, the lubricant tank may be connected to a conventionally known wire drawing device, and the equipment cost is also low.

  Austenitic stainless steel wire was drawn by the method of the present invention.

Example 1
Lubricant: Oil based lubricant (manufactured by Japan Unako Co., Ltd .: PZ-1105)
Bus bar heating temperature: 150 ° C
Bus diameter: 5.5 mmφ
Finished diameter: 0.34 mmφ
Area reduction rate of each die: 40 to 43%, 11 times reduction Total area reduction rate: 96.2%
Each wire diameter is as follows.

5.5mmφ → 4.3 mmφ → 3.35 mmφ → 2.6 mmφ → 2.0 mmφ → 1.55 mmφ → 1.20 mmφ → 0.93 mmφ → 0.73 mmφ → 0.57 mmφ → 0.445 mmφ → 0.34 mmφ
Drawing speed of final wire diameter: 250m / min
When the surface state of the finished line after processing was inspected, there was no abnormality in the surface state, and no hair cracks or voids were observed in the internal structure, and the normal structure was obtained. The tensile strength was 2200 N / mm ² , which was a desired strength.

Example 2
Lubricant: Aqueous lubricant (manufactured by Nisshin Chemical Laboratory Co., Ltd .: Ratpur NN-21)
Bus bar heating temperature: 90 ° C
Bus diameter: 5.5 mmφ
Finished diameter: 0.34 mmφ
Area reduction ratio of each die: 38-36%, 12 pulling total area reduction ratio: 96.2%
Each wire diameter is as follows.

5.5mmφ → 4.35mmφ → 3.44 mmφ → 2.72 mmφ → 2.16 mmφ → 1.69 mmφ → 1.34 mmφ → 1.06 mmφ → 0.83 mmφ → 0.66 mmφ → 0.52 mmφ → 0.42 mmφ → 0.34 mmφ
Drawing speed of final wire diameter: 200m / min
When the surface state of the finished line after processing was inspected, there was no abnormality in the surface state, and no hair cracks or voids were observed in the internal structure, and the normal structure was obtained. The tensile strength was 2250 N / mm ² , which was a desired strength.

  In the conventional process, there are three types of wire drawing machines: 18 "x 8H (18" means 18 inch hook diameter, 8H means 8 pieces, and so on), 16 "x 8H, 12" x 8H, total A bright annealing treatment was required at each diameter before drawing at 24H and in the 16 "and 12" kettles. On the other hand, as can be seen from the above examples, according to the present invention, only one type of wire drawing machine of 11H to 12H is used, and no bright annealing is required, and a completely rational production is possible.

10 ... Back tension roller, 20 ... Dice container, 30 ... Dies, 40 ... Lubricant tank, 42 ... Heater, 44 ... Lubricant supply pipe, 46 ... Circulation pump, 48 ... Return pipe, 50 ... Thermometer

Claims (7)

Passing a tensioned austenitic stainless steel bus through a heated liquid lubricant and heating the bus;
A process of drawing the heated busbar;
An austenitic stainless steel wire drawing method comprising: A process of spraying the heated liquid lubricant on the tensioned austenitic stainless steel bus and heating the bus,
A process of drawing the heated busbar;
An austenitic stainless steel wire drawing method comprising: The method according to claim 1 or 2, wherein the lubricant is a water-soluble lubricant, and the heating temperature of the bus bar is higher than normal temperature and lower than 100 ° C. The method according to claim 1, wherein the lubricant is an oil-based lubricant, and the heating temperature of the bus bar is 100 ° C. or higher and 250 ° C. or lower. The method according to claim 1, wherein the bus bar heating step and the bus bar drawing step are repeated a plurality of times. Tension applying means for applying tension to the austenitic stainless steel bus wire to be drawn;
A die container that heats the austenitic stainless steel busbar by passing a heated austenitic stainless steel busbar supplied with a lubricant and is tensioned, and
A drawing means for drawing a heated austenitic stainless steel busbar;
A lubricant tank containing a lubricant;
A circulation path for circulating the lubricant between the die container and the lubricant tank;
Heating means for heating the lubricant in the lubricant tank;
An austenitic stainless steel wire drawing machine comprising: 7. The austenitic stainless steel wire drawing apparatus according to claim 6, wherein the tension applying means is a back tension roller.

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