JPH03291113A - Manufacture of wire material for cold forging - Google Patents

Abstract

PURPOSE:To accelerate the line speed for in-line treatment without making the treatment vessel long by treating the wire material with the surface conditioner at the entrance side of the phosphate coating process. CONSTITUTION:The required lubricating property is held because the closely contacting property of the phosphate coating 12 is improved, even the stuck amt. 12 of the phosphoric acid coating 12 is decreased by treating the wire material with the surface conditioner as the preceeding treatment at the entrance side of the phosphate coating process, and the time for the lubricating surface preparation can be able to shorten. Accordingly, without making the treating vessel long, the line speed is accelerated and it is greatly effective for the manufacture of the wire material for cold forging.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing wire rods for cold forging (including steel bars) by an in-line continuous wire drawing method. The present invention relates to a method for manufacturing wire rods for cold forging, which aims to improve line speed by adding a pretreatment step to improve adhesion.

Conventional technology Wire rods for cold forging ensure roundness and strength through wire drawing, and the presence of a lubricating film on the surface allows for cold forging as is, and is used by manufacturers for secondary and tertiary processing of wire rods. This is what is being done.

The manufacturing methods for such cold forging wire rods include: ■ Batch processing and ■ In-line processing (for example, Japanese Patent Application Laid-Open No. 56-163
047) is known.

■Batch processing involves descaling the hot-rolled and wound coil in a pickling tank, and after lubrication and base treatment with zinc phosphate, etc.
This is a method of wire drawing using a reactive soap treatment such as lime soap or sodium stearate, or a lubricant before the die.

Since this method processes the wire in the coil state, the pickling liquid and lubricant do not reach the parts where the wires are in contact with each other, resulting in poor descaling and uneven lubrication, resulting in seizure during wire drawing or cold forging. It causes. Additionally, there are drawbacks such as pollution problems due to the use of acids and low productivity.

On the other hand, (2) in-line processing is a method in which the wire unwound from the coil is descaled by mechanical descaling such as shot blasting, and then the wire is drawn through a lubricating base treatment with zinc phosphate or the like.

In this method, the descaling and lubrication treatment is carried out in the so-called wire running state, so that wire rods of good quality can be produced without defective descaling or uneven lubrication as in the batch process (2).

Problems to be Solved by the Invention However, in conventional in-line processing, the processing time for lubricating base treatment with zinc phosphate, etc. is limited by the wire drawing speed, and the formation of a lubricating film involves chemical reactions. Therefore, there was a limit to increasing the line speed.

That is, it is possible to increase the line speed by increasing the length of the lubrication base treatment tank, but there is a limit to the length of the treatment tank due to installation space and equipment costs. For this reason, conventional inline processing has not been able to significantly increase the line speed.

This invention was made to solve the problem of increasing the line speed of the conventional in-line processing, and by performing a treatment to improve the adhesion of the lubricant film before the lubrication base treatment, the treatment tank can be used for a longer time. The purpose of this paper is to propose a method for manufacturing wire rods for cold forging that allows the line speed to be increased without causing any increase in line speed.

Means for Solving the Problems A method for manufacturing a wire rod for cold forging according to the present invention is to descale the wire rod by mechanical descaling such as shot blasting while moving the wire rod linearly and continuously in the longitudinal direction. Summary of a method to improve the adhesion of the phosphate film and increase line speed by applying surface conditioning agent treatment before the phosphate film treatment when drawing wire after salt film treatment and lubrication treatment. That is.

Effect By applying a surface conditioner treatment as a pretreatment for phosphate film treatment, although the amount of phosphate film adhesion is reduced, the adhesion of the phosphate film is improved and the desired lubrication performance is not achieved. This makes it possible to shorten the lubrication base treatment time and increase line speed without increasing the length of the treatment tank.

The surface conditioner may be any brand or main component as long as it has the effect of promoting crystal nucleation of the phosphate film and increasing the number of crystal nuclei. For example, a surface conditioner containing Ti colloidal as a main component can be used.

In a surface conditioning agent containing Ti colloidal as a main component, titanium phosphate in the liquid chemically adsorbs to the metal surface as a poorly soluble colloid, creating a potential difference and becoming an active site (cathode). When there are many active points, the speed at which they fill in between the crystals is fast, so the film formation reaction is completed in a short time.

As a pretreatment for phosphate film treatment, the adhesion of the lubricant film can be improved by treating it with a surface conditioner that has the effect of promoting the formation of crystal nuclei in the phosphate film. As a result, the line speed can be increased without increasing the length of the processing tank.

Example FIG. 1 is a block diagram showing the manufacturing process of this invention.

That is, the rewound wire is straightened and partially descaled in a roll bender (2) and then descaled in a shot blasting step (3). The reason why mechanical descaling such as shot blasting is used as the descaling means is because in-line treatment and removal of acid pollution are assumed.

After descaling, the wire is preheated to a desired temperature in the preheating step (4) and then led to the surface treatment step (5) where it is treated with a surface conditioner and then subjected to the next phosphate film treatment step (6).
).

In the phosphate film treatment step (6), zinc phosphate treatment is performed. In this case, since the surface conditioning agent is used, the amount of zinc phosphate film deposited is reduced, but a film with good adhesion is obtained, so the amount of zinc phosphate film deposited is, for example, 5 g/m. (Conventionally 7 to 8 g/m'), at least the same lubrication performance as the conventional one can be obtained.

By the way, the processing conditions for this phosphate treatment step are as follows:
For example, total acidity 160 points, temperature 80℃, immersion time (
Processing time) 4 to 8 seconds is sufficient. In addition to zinc phosphate, zinc calcium phosphate may be used for the zinc phosphate treatment.

After the zinc phosphate treatment, a cleaning step (7) is performed, and a lime soap treatment (8) and a non-reactive soap treatment (8') are performed in a lubrication treatment step. Here, the lime soap treatment conditions include a lime concentration of 14 to 15%, an oil content of 3.0 to 3.5%, and a treatment temperature of 4.
0-50°C, also for non-reactive soap treatment.

In this case, the concentration may be 350 g/l and the treatment temperature may be room temperature. In addition,
The treatment time is not particularly limited because it is a physical adhesion rather than a chemical reaction.

After the lubrication treatment, the drying process (9) is followed by the final wire drawing process (10).
), but in the drying step (9), it is desirable to keep the wire surface temperature at a maximum of 120°C in consideration of thermal changes in the zinc phosphate film, and to set the processing time to allow sufficient drying before wire drawing. do. As the drying means, a hot air drying oven, an infrared drying oven, a high frequency induction heating oven, etc. may be used.

After drying, the wire is drawn using a normal die and wound up, or a dry powder lubricant is applied as a lubricant before the die, and the wire is drawn using a normal die and wound up.

Note that since the zinc phosphate film has good adhesion, it is also possible to omit the lubrication treatment step.

FIG. 2 is a schematic diagram showing an example of a lubricating film structure according to the present invention, in which (11) is the base material (Fe), (12) is a zinc phosphate film, (13) is a lime soap treated film, and (14) is a The non-reactive soap treatment film (15) is the pre-die lubricant film, (
A) is zinc phosphate film (12), lime soap treated film (1)
3) and a lubricant film consisting of a pre-die lubricant film (15); (B) a lubricant film consisting of a zinc phosphate film (12), a non-reactive soap treatment film (14) and a pre-die lubricant film (15); (C) is a lubricating film consisting of a zinc phosphate film (12) and a lime soap treatment film (13) (no lubrication before the die); (D) is a zinc phosphate film (12) and a non-reactive soap treatment A lubricating film (no pre-dice lubrication) consisting of a film (14) (E) shows a lubricating film (no f4 lubricating treatment) consisting of a zinc phosphate film (12) and a pre-die lubricant film (15), respectively.

Next, the results of applying this invention method to an actual line will be explained in comparison with the conventional method.

The manufacturing conditions in this example are shown in Table 1, and the processing conditions and line speeds are shown in Table 2.
2IIEIIφ, load: 3000gr, temperature: room temperature)
The results are shown in Table 3, and the results of the cold forward extrusion test of the drawn wire material are shown in Table 4 and FIG. 3, respectively, in comparison with the conventional method (no surface conditioner used).

As is clear from Table 2, Table 3, Table 4, and Figure 3, the use of a surface conditioner generates more crystal nuclei in the zinc phosphate film, resulting in zinc verate deposition compared to the conventional method. Although the amount decreased, there was no problem with the retraction of the pre-die lubrication (see Table 2), and the effect of improving the adhesion of the film (Table 3)
(see table) improves the forward extrusion limit (see table 4) and extrusion stress (see figure 3) during cold forging, and as a result, increases the line speed (see table 2) to about twice the conventional method. We were able to.

As explained in detail below, this invention is a method for descaling rolled wire rods.
Lubricating treatment - In a continuous wire drawing method, the adhesion of the zinc phosphate film can be improved by performing a treatment with a surface sit preparation before the phosphate film treatment with zinc phosphate. Even if the amount of zinc oxide coating is small, the cold forgeability of the drawn wire material can be significantly improved.

Therefore 9. According to the method of this invention, it is possible to increase the line speed for in-line processing without increasing the length of the lubrication treatment tank, improving productivity and producing a great effect on the production of wire rods for cold forging. It is something to play. .

[Brief explanation of drawings]

Fig. 1 is a process diagram showing an example of the manufacturing process of this invention, Figs. 2 (A) to (E) are schematic diagrams showing an example of a film structure in this invention, Fig. 3 It is a figure showing forward extrusion, force, and force in an example. 1.Payoff reel 2.Roll benoder 3.Shot blasting step 4.Preheating step 5.Surface treatment step 6.Phosphate film treatment step 7.Washing step 8. Lime soap treatment process 8゛・Non-reactive stone finishing process 9...Drying process 10...Wire drawing process

Claims (1)

[Claims] In a method for manufacturing wire rods for cold forging in which wire rods are continuously moved while being subjected to descaling, phosphate coating treatment, and lubrication treatment before being drawn, a surface conditioning agent is applied to the wire rods on the entry side of the phosphate coating treatment process. A method for producing a wire rod for cold forging, characterized by subjecting it to treatment by.