JPS62207512A - Continuous drawing method for wire - Google Patents

Abstract

PURPOSE:To perform a continuous drawing of a wire at a high passing speed by applying a zinc-calium phosphate lubricating substrate to an iron-zinc alloy layer on the descaled surface of the wire and performing lubricating treatment with a stearate. CONSTITUTION:After a wire is descaled by a mechanical descaler with the wire straight and continuously carried in the longitudinal direction, the wire is blasted with iron-zinc particles to form an iron-zinc alloy layer on the wire surface. The wire is preheated at a preferable temp. in 80-90 deg.C and is passed through a zinc-calcium phosphate solution to perform a lubricating substrate treatment to deposit said phosphate on the surface of the iron-zinc alloy. Then, the wire is washed with water to remove an excess deposit and is passed through a calcium stearate or a sodium stearate solution to perform the lubrication treatment. The lubrication treated wire is rapidly dried with infrared rays and is drawn with a die.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a wire rod for cold forging in which wire rods (including steel bars) are continuously moved and subjected to descaling, lubrication surface treatment, and lubrication treatment before being drawn. Concerning continuous wire drawing method.

Conventional technology and its problems Drawn wire rods for cold forging ensure roundness and strength through wire drawing, and can be cold forged as is due to the presence of a lubricating film on the surface. It is frequently used by secondary and tertiary processing manufacturers.

This drawn wire material for cold forging is usually manufactured by batch processing. That is, the hot-rolled and wound coil is descaled in a pickling tank, immersed in a lubricating base treatment tank with zinc phosphate, etc., then immersed in a stearic acid bath, dried, and then drawn with a wire drawing die. It was done and rolled up. Since these treatments are performed in a coiled state, the pickling liquid and lubricant do not reach the parts where the wires are in contact with each other, resulting in uneven lubrication, which causes seizure during wire drawing and cold forging. . In addition, the amount of chemicals (processing agents) in the processing tank was large, making it difficult to manage chemicals between coils, causing quality variations.

Therefore, the present inventor has proposed and implemented several methods for carrying out these processes continuously.

For example, the wire unwound from the coil is mechanically descaled using a roller bending descaler or shot blasting, then a lubricating base treatment such as phosphoric acid ZT1 is applied, and then stearin 112Ca or stearate Na is treated on top of that, and then infrared rays are applied to the wire. This is a method of drawing and winding the wire after rapid drying (Japanese Unexamined Patent Publication No. 163047/1983). In this method, the lubrication process is carried out while the wire is running, so there is no uneven lubrication like in the batch process and the quality is improved.However, since the formation of the lubricating film involves a chemical reaction, it is not possible to increase the threading speed, resulting in production There was a restriction that the gender was bad. In addition, to improve cold forgeability after wire drawing, zinc phosphate Ca, which has excellent heat resistance, is used as a lubricating base treatment agent.
It is also proposed to use (Japanese Patent Application Laid-Open No. 6O-174880) L
However, this has poor chemical conversion properties compared to zTl phosphate,
The disadvantage was that the wire running speed had to be considerably reduced. As a method of increasing these wire threading speeds, a method of applying ultrasonic vibrations within the lubricating tank has been proposed, but this method has drawbacks such as complicated equipment and increased equipment costs.

Purpose of the Invention The present invention has been made to solve the above-mentioned conventional problems, and provides a continuous wire drawing method that can increase the amount of zinc phosphate Ca deposited and increase the wire threading speed, especially in lubricating base treatment. The purpose is to propose the following.

DESCRIPTION OF THE INVENTION The present invention is a method for manufacturing a wire rod for cold forging through a continuous wire threading process.

That is, a hot-rolled wire rod is moved linearly and continuously in the longitudinal direction, and after descaling, blasting with iron and zinc particles is performed to form an uneven iron-zinc alloy coating on the surface of the wire rod. It is characterized by forming zinc phosphate Ca as a lubricating base treatment on the zinc phosphate Ca, and further performing a lubricating treatment with stearic acid Ca or stearin M1111a on the zinc phosphate Ca, and drawing after drying.

The method of this invention will be explained in detail below.

Figure 1 shows the steps of unwinding the hot-rolled coil from the payoff stand (1), descaling, lubrication base treatment, water washing, lubrication treatment, drying, wire drawing, and winding. It is the same as 163047/1984).

This invention is characterized in that the descaling step (2) in FIG. 1 includes a step of forming an iron/zinc alloy coating on the wire surface by blasting iron/zinc particles after a normal mechanical descaling.

Blasting with iron/zinc particles is known as
As disclosed in No. 12, iron grains are used as cores, and the grains whose surfaces are coated with zinc via an iron-zinc alloy layer are blasted using a conventional method. The iron/zinc coating is formed to promote the adhesion of zinc phosphate Ca, a lubricating base treatment agent, and may be plated, but since the coating formed by blasting is porous, zinc phosphate C
This is a preferred method because it promotes the penetration of a.

Zinc phosphate Ca is attached to the surface of the iron/zinc coating formed in this way in the lubrication base treatment step (4), but since zinc phosphate Ca adhesion progresses by reaction with iron, the reaction time becomes longer. . Therefore, preheat the wire in advance (80 to 9
0° C.) is preferable as a means of increasing the wire running speed. (3) is the preheating step.

In addition, zinc phosphate Ca solution for lubricating base treatment is also 70 to 80%
Preferably, the temperature is raised to 0.degree. C. because adhesion is promoted. From the viewpoint of adhesion, the ratio of Ca to ZTI in zinc phosphate Ca is as follows: zinc phosphate Ca coating (solution concentration 160 points)
It is clear from Figure 3, which shows the relationship between the Ca/Zn ratio and the adhesion amount, that it is better not to contain Ca, but in terms of lubricating performance (
In particular, since Ca is required for heat resistance), a Ca/Zn ratio of 0.3 or more is preferable. Moreover, if it is 1.0 or more, the amount of adhesion will decrease and the lubricity will be adversely affected, so it is preferably 1.0 or less. Further, the density needs to be 160 to 200 points in order to carry out the wiring process in a short time (10 to 20 seconds). Note that a point is a unit of concentration of the phosphate treatment solution, which is 0.18 Na0 required to neutralize 10d of the phosphate treatment solution.
) is the d number of l.

Next, in a water washing step (5), excess zinc phosphate Ca solution is washed away, and in a lubrication treatment step (6), the wire is passed through a Ca stearate solution or a positive stearate solution for lubrication treatment. When using Ca stearate as a lubricant, in order to obtain a coating amount of 5C14 or more, it is preferable that the concentration is 300 g/r1 or more and the wire passing time is 2 to 3 seconds. In addition, when using stearic acid, the temperature of the solution should be adjusted to 70 to 90% in order to ensure a reaction layer (zinc stearate) of 1 g or more generated by the substitution reaction with the zinc phosphate Ca coating.
The temperature was raised to 0°C, the concentration was increased to 90a/, 11 or more, and the treatment time (
(including reaction time) is preferably 20 seconds or more. The reason for this is that the film structure when the Ca stearate treatment is performed is shown in Figure 2a, and the film structure when the Na stearate treatment is performed as shown in Figure 2a.
In the case of treatment, Ca stearate is physically adsorbed, and zinc phosphate Ca coating (11) and stearate Ca coating (1
2), whereas in the case of stearic acid septa treatment, it is chemical adsorption, and the zinc phosphate Ca coating (11),
This is because the reaction layer (13) and the Na stearate coating (14) are different in coating composition, and the lubrication performance of the Na stearate coating is superior. In Figure 2, (10 is the subway.

After the lubrication treatment, drying and chemical reactions are rapidly promoted in a drying chamber (7) using infrared rays, etc., and in a wire drawing step (8), the wire is drawn using an ordinary die and wound.

The lubricant is dried using a hot air drying oven, a high frequency induction heating oven,
Although any method such as an infrared drying oven may be used, it is preferable to carry out the drying at a wire surface temperature of 200° C. or lower in view of the deterioration characteristics of the lubricant.

In addition, wire drawing with a wire drawing die is performed to give the wire a predetermined strength, and since it is necessary to ensure cold forgeability even after that, it is necessary to draw a wire with a large area reduction rate like normal wire drawing. Rather, the upper limit is 30% at most.

In addition, although we mentioned here that the process from unwinding the wire coil to winding after treatment is carried out continuously, rust will not occur if an iron/zinc alloy film is formed on the wire surface by blasting with iron/zinc particles. , the steps up to this step may be performed on a separate line, and the coiled material may be brought to the lubrication base treatment step.

Example A wire rod with an iron/zinc alloy coating of approximately 100 mg/dm2 formed by iron/zinc particle blasting after normal shot blasting was preheated to 80°C, and the wire threading speed was increased to 30 m/min using the processing equipment below. The wire was subjected to processing at a speed of 100 m/min, and the wire drawing condition and cold workability after wire drawing were evaluated. In addition, as a comparative example, the cold workability of a specimen subjected to the same treatment except for the iron/zinc particle blasting treatment after ordinary shot blasting was evaluated.

Treatment equipment> ■ Lubricating base treatment tank Zinc phosphate Ca solution: Ca/Zn = 0.3 concentration: 16
0 point temperature 2 80℃ Tank length 210m ■Lubrication treatment tank Ca stearate solution concentration: 300g/Q temperature: Room temperature Tank length: 4m (However, it is physical attachment and reaction time is not required. Therefore, effective lubrication (Processing section is approximately 30cm) ■Drying hot air drying oven: Furnace temperature 80℃, furnace length 3m ■Wire drawing area reduction rate: Approximately 18% (22mmφ → 19.9mmφ) Lubricant before die: Commercially available lubricant (product name Koshin U ) The results of this example are shown in Table 1. In Table 1, the zinc phosphate Ca coating is the value measured by gravimetrically measuring the adhesion amount of zinc phosphate Ca by dissolving 5% Cr in acid, and the cold forgeability is measured by performing forward multi-stage extrusion and extrusion area reduction. Rate 73.5
These are the results evaluated based on the presence or absence of burn-in in %. In addition, a Bounden test was conducted on extruded materials processed at a wire passing speed of 50 m/min, and a comparison of the friction coefficients with and without the iron-zinc alloy coating is shown in FIG.

As is clear from Table 1, in the method of the present invention in which blasting is performed with iron/zinc particles, the cold workability does not deteriorate up to a wire passing speed of 60 m/min, whereas in the conventional method, the limit is up to 40 m/min. Furthermore, as is clear from FIG. 4, good values were also shown in the Bounden test.

(Left space below) As described in detail, this invention method involves continuous descaling, lubrication treatment, and wire drawing of hot rolled wire rods, in which iron and zinc are added to improve cold workability. By using zinc phosphate Ca as a lubricating surface treatment agent after particle blasting, the wire threading speed can be increased by about 1.5 times.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an outline of the treatment line of the present invention, Fig. 2 is a diagram showing a coating structure when a wire rod is subjected to Ca stearate and stearic acid positive treatment, and Fig. 3 is a diagram showing a coating composition using Ca stearate and Ca stearate.
FIG. 4 is a diagram showing the relationship between the Ca/Zn ratio in the bath and the amount of film deposited during treatment, and FIG. 4 is a diagram showing the bounden test results of materials treated with and without iron-zinc alloy coating. 1...Payoff stand, 2...Descaling process,
3... Preheating process, 4... Lubrication base treatment process, 5...
・Water washing process, 6... Lubrication treatment process, 7... Drying process, 8... Wire drawing process, 9... Winding process. JP-A-62-2F) 7512 (5)

Claims (1)

[Claims] The wire rod is moved linearly and continuously in the longitudinal direction, and after descaling, it is blasted with iron and zinc particles to form an iron and zinc alloy layer on the surface of the wire rod, and then passed through a zinc phosphate Ca solution to perform a lubricating base treatment. 1. A continuous wire drawing method for a wire rod, which is characterized in that the wire rod is drawn after being dried, washed with water, passed through a solution of Ca stearate or Na stearate for lubrication treatment, and then dried.