JPH01273609A - Continuous wire drawing method for titanium or titanium alloy - Google Patents

Abstract

PURPOSE:To generate a film of good adhesion and to improve the wire drawability by performing descaling, plating pretreatment and Ni plating with continuously and linearly moving a Ti or Ti alloy element wire in the longitudinal direction. CONSTITUTION:The descaling 1 by mechanical descaling of shot blasting, etc., is performed by moving the element wire consisting of Ti or Ti alloy linearly in continuation. The element wire thereof is then subjected to cleaning by executing the alkali electrolytic processing 2 by the anode current density of 5-20A/dm<2>. Thereafter, the shot blasting agent on the Ti surface is cleaned 3 and the oxidized coating is removed 4 by melting by an acid liquid. The numerous kinds of the Ti surfaces are activated by the acid liquid and strongly combined with the plating metal of the succeeding stage. The Ni plating treatment in 20-60mus film thickness is performed after a washing treatment 5 and wire drawing 9 is performed after washing treatment 7 and drying treatment. As a result, the adhesion of a Ni plating film is improved and the efficiency and quality in wire drawing can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for drawing titanium or titanium alloy.
More specifically, the present invention relates to a method of drawing wire by improving the lubricating ability of the wire surface using a nickel plating method.

Conventional technology Titanium or titanium alloy has excellent durability, so
Used in a wide range of fields. In particular, when used as a wire rod, it is difficult to draw the wire in the manufacturing process. The reason is that titanium or titanium alloys have poor toughness.
This is because not only is wire drawing difficult, but also effective lubrication treatment is difficult due to its chemical stability.

Conventionally, batch processing has been used as a method for manufacturing titanium or titanium-gold wire. The main method is so-called scaling, in which scale is generated on the surface of the wire by annealing it, a fluorine-based resin is applied thereon, and after drying, the wire is drawn using a dry powder lubricant. In the case of 6-titanium wire, it is chemically very stable and cannot be treated with zinc phosphate, which is applied to carbon steel wire.

In this scaling process, the fluororesin coating sometimes has poor lubricating ability, and when processing becomes difficult, the film breaks during processing, so annealing and fluororesin coating treatment are repeated several times. After wire drawing is completed, scale adheres to the surface of the wire, so it is removed by pickling with nitric-hydrofluoric acid or the like. At this time, depending on the pickling conditions, the product may become rough and may lose its value. Furthermore, in the conventional batch processing method, the wires come into contact with each other, and the lubricant (fluororesin) does not circulate around this portion, resulting in uneven lubrication.

Recently, in order to improve the above-mentioned drawbacks of scaling, a method has been adopted in which the surface of the wire is plated with nickel and the wire is drawn. This method has been around for a long time (for example,
According to literature, it was already announced in 1964. )
It has been implemented. However, in the case of titanium wires, an oxide film is formed very easily, and as a matter of course, if an oxide film is present during plating, plating with good adhesion cannot be obtained.

Therefore, various methods regarding nickel plating pretreatment have been proposed recently. This special nickel plating pretreatment is intended to improve the lubrication ability during wire drawing. Representative examples are shown below.

■ Fluorine ions and Ni, Cu, Zn
, Ti or Ti in an aqueous solution of an inorganic acid or an inorganic mixed acid containing heavy metal ions that are relatively easy to plate, such as Fe.
A method of electrolytically treating alloy wire using alternating current or alternating current or superimposed alternating current, and then electrolytically plating it with nickel (Japanese Patent Application Laid-open No. 1983-
410793).

■ Using an electrolytic solution prepared by adding 5 to 100 d/l of hydrofluoric acid (concentration 47%) to a 5 to 50 wt% solution of concentrated sulfuric acid (1 degree 98%), an insoluble horizontal plate such as lead or carbon is used as a cathode, and Ti
Or further nickel plating on Ti alloy (
JP 61-119695 A).

■ Etching the Ti or Ti alloy surface to reduce the number of corrosion holes to 1 to 5 x 10"/-2 and the diameter of the holes to 0.5".
A method of forming holes with a depth of 1 to 10 μm, followed by nickel plating, and then precious metal plating (Japanese Patent Publication No. 170594/1986).

However, in these nickel plating pretreatment methods, the adhesion of the plating film is greatly influenced by the quality of the plating pretreatment. If the adhesion of the plating film is poor, the film breaks during wire drawing, and the plating needs to be reprocessed each time.

Problem to be Solved by the Invention The problem to be solved by the present invention is to improve the conventional scaling and nickel plating pretreatment method,
The purpose is to improve the adhesion of the plating film and improve the efficiency and quality of wire drawing.

Means for Solving the Problems The method for continuous wire drawing of titanium or titanium alloy of the present invention involves continuously moving a wire made of titanium or titanium alloy in a straight line, and subjecting the wire to shot blasting to remove the wire. Perform scaling, perform alkaline electrolytic treatment at a current density of 05-20A/ds'', perform nickel plating treatment with a film thickness of 20-60μ after water washing, pickling and water washing, and after water washing and drying treatment. The above problem is solved by wire drawing.

In the continuous wire drawing method of the present invention, the above-mentioned problem can also be solved by once winding up the wire after washing and drying, and by drawing the wire on another line.

Function: The method of the present invention is superior to conventional scale lubrication, which has disadvantages such as poor lubrication ability, an increase in the number of annealing steps as processing becomes difficult, and residual scale is removed at the product stage, which sometimes causes surface roughness. In order to eliminate the drawbacks of batch processing, we replaced batch processing with inline processing,
Furthermore, nickel plating is formed on the surface of the Ti wire. When forming this nickel plating, improvements are made to the plating pretreatment in order to improve the adhesion of the plating film.

Therefore, in the method of the present invention, descaling is performed by mechanical descaling such as shot blasting while moving the Ti or Ti alloy wire linearly and continuously in the longitudinal direction, and the adhesion to alkaline electrolytic treatment and pickling treatment is improved. After that, the wire is drawn using lubrication before the die. In this case, the nickel plating acts as a carrier film for the pre-die lubricant (dry powder lubricant).

In the case of conventional batch processing, contact portions occur between wires, resulting in uneven lubrication. In particular, when plating as in the present invention is carried out, descaling and alkaline electrolytic treatment, which are pre-plating treatments, and descaling, nickel plating, and nickel plating of the contact areas between wires in the plating treatment are necessary. To avoid such unevenness, descaling, plating pretreatment, plating, and in some cases wire drawing are carried out while moving the wire linearly and continuously in the longitudinal direction.

In addition, in the method of the present invention, when manufacturing an ultrafine wire, it is necessary to carry out annealing in an intermediate step because of work hardening due to wire drawing. In this case, the annealing temperature is about 700°C and the annealing does not remove the nickel plating. Therefore, if bright annealing without scale generation is performed, wire drawing can be immediately proceeded again.

However, as processing progresses, the nickel plating will eventually disappear. In this case, Schottplastr wire drawing may be repeated.

EXAMPLE The continuous wire drawing method of titanium or titanium alloy of the present invention will be explained with reference to FIG. Descaling the wire by shot blasting (1), alkaline electrolytic treatment with a current density of 0.5-20 A/dm2 (2), washing with water (3), pickling (4), Water washing (5> Film thickness after treatment: 20-
No 60μ nickel plating treatment (6), washing with water (7) and drying (8) F! This process is followed by wire drawing (9).

The method of the present invention can further include winding up the strand (10) once after the washing 7) and drying (8) treatments, and drawing the strand in another line (11).

Each step in the method of the present invention will be explained below.

■ Shotblasting process Perform 100% descaling using normal shotblasting. In this case, an abrasive material containing a grid or Fe or Ni powder is used to destroy the oxidized coating on the Ti base material, and at the same time, a portion of the abrasive material is left on the base material to serve as a core during plating. Incidentally, the shot blasting density may be approximately 20 kg/j2 or more (100 Ay/j2 in the case of hot-rolled scale), which allows 100% descaling of the oxidized coating of the Ti base material.

(2) Alkaline electrolytic treatment Anodization is performed. This treatment prevents hydrogen from entering the Ti base material, so there is no need to consider hydrogen embrittlement.

In addition, the surface potential is pulled by the abrasive material (Fe) remaining on the Ti surface in the shot blasting described above, and no anodic oxidation occurs on the Ti surface.Furthermore, the abrasive material (Fe) on the Ti surface
Electrolysis occurs and has a cleaning effect. The anode current density requires 0.5-20A/da2.

The reason for this is that if it is less than 0.5A/rh', there is no electrolytic effect (insufficient cleaning ability), and if it is more than 20A/dm2, a passivation film is formed, and the adhesion of the plating film in the subsequent process is extremely poor. This is because it is bad for

(2) Acid cleaning treatment The abrasive material (Fe) on the Ti surface (seeds sown on the surface of the substrate) is cleaned in the previous step, and the oxidized coating is dissolved and removed with an acid solution. The countless species on the Ti surface are activated by the acid solution and are strongly bonded to the plating metal in the next step. In order to satisfy the above phenomenon, the M washing conditions are, for example, when HC1 is used, the treatment concentration is -10% and the treatment time is about -5 to 30 seconds, but these conditions can be selected as appropriate depending on the acid solution used.

(2) Nickel (Ni) Treatment Needless to say, the lubrication ability of Ni plating requires that annealing (approximately 700'C) be performed during wire drawing in order to produce ultra-fine Ti or Ti alloy wire.

Considering the melting point of Ni, nickel plating will not disappear due to annealing. The thickness of the plating is set to 20-60 μm in consideration of the wire drawing results described later.

If the diameter is less than 20 μm, there is no effect of wire drawing lubrication, and if the diameter is 60 μm or more, the plating peels off significantly during wire drawing, which actually worsens the wire drawability. The plating conditions may be such that the above-mentioned film thickness of 20-60 .mu.+n is obtained. However, considering that this is inline processing, the processing time is set to within several tens of seconds.

After finger removal, the base metal is exposed on the pickled (activated) metal surface, and when the plated metal is precipitated, the atoms of the base metal and the plated metal atoms approach the atomic order of distance.
The van der Waals force acts, creating an adhesion force. In addition, in the case of the present invention, the surface irregularities caused by shot blasting work positively as an anchor effect.

■For drying after plating and washing with water, normal hot air drying is sufficient. Insufficient drying may cause seizure during wire drawing.
Requires attention. The drying temperature is not particularly limited; in short,
It is necessary to dry the wire sufficiently before drawing it. Considering economy, the maximum temperature should be around 200℃.

■Wire drawing The descaled and Ni-plated Ti wire is drawn using a normal hole die. During wire drawing, a commercially available dry powder lubricant (for example, Koshin Y107 Kyoei Co., Ltd.) may be used for pre-die lubrication, and a wire drawing area reduction rate of 10 to 15% per bath is appropriate.

■ Wire drawing after winding It is also possible to wind the wire once after the above-mentioned in-line treatment and then draw it on a separate line.

■Water washing treatment In the present invention, water washing treatment is carried out after each of the alkaline electrolytic treatment, pickling treatment, and nickel plating treatment. The purpose of this treatment is to completely remove unnecessary treatment liquids that adhered to the wire during the pretreatment.

The water washing treatment is always carried out in order to prevent the pretreatment liquids from being mixed into the subsequent treatment liquids. As long as the water washing treatment can completely remove unnecessary pretreatment liquid adhering to the strands, the conditions for the water washing treatment can be selected as necessary.

Specific examples of the method of the present invention will be described below.

Specific Example 1> (1) Test material: Pure Ti element 1! (Diameter 11.5-mm) (2
) Shot blast; abrasive material - grit projection density -
40λy/x2 Projection method - Normal shot blasting (3) Alkaline electrolysis: Anodization current density 15A/d1 Treatment liquid - 3% sodium orthosilicate treatment time - 20 seconds (4) Pickling: HCl1. O%XR,, TX10 seconds (
5) Plating: Nickel plating treatment solution - Watt bath, current density = 5A/d information 2 Plating film thickness = 20-60μ plating, treatment temperature -50℃ (6) Wire drawing: Wire drawing speed - 30/min1 Area reduction rate per bus = 1. O-15% die front lubrication/Koshin Y
107 Die shape = 2α = 14゛ (8) Water washing Alkaline electrolytic treatment, pickling treatment, nickel
Performed after each plating process.

(9) Wire drawing results: Plating pretreatment, plating, and wire drawing were performed continuously in-line under the above conditions. The results are shown in Table 1. As a comparative example, the wire drawing results of the conventional oxidized scale drawing are also shown.

Table 1 (-outside the scope of the present invention) Specific Example 2 Regarding the adhesion of plating film, the difference between the present invention method and the conventional nickel plating method (for example, using concentrated sulfuric acid or hydrofluoric acid as a descaling method) The results of the comparison are shown in Table 2.

Second surface adhesion Inventive method: Specific implementation Same as IA1 (however, plating amount = 20 μm) Comparative example: Sulfuric and decafluoric acid electrolyte solution (no shot blasting) As shown in Table 2, the present invention Since the method uses shot blasting to embed Fe, which forms the core of the plating, the adhesion of the plating is better than that of the comparative example, which is simply pickled.

Specific Example 3 Table 3 shows the relationship between the anode current density and the adhesion of the plating film in alkaline electrolysis.

The implementation conditions are specific implementation PA1 except for alkaline electrolysis.
It is similar to

Table 3 (-Outside the scope of the present invention) Effects According to the method of the present invention, a nickel plating film with good adhesion can be obtained, and wire drawability is improved.As a result, the process of annealing, lubrication, etc. The process can be shortened. Furthermore, there is no need to remove residual scale at the product stage and there is no problem of rough skin.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of the method of the present invention.

Claims (2)

[Claims] (1) Continuously moving a wire made of titanium or titanium alloy in a straight line, shot blasting the wire to descale it, 0.5-20A/dm^
After applying alkaline electrolytic treatment at a current density of 2, washing with water, pickling, and washing with water, nickel with a film thickness of 20 to 60 μm is applied.
A continuous wire drawing method for titanium or titanium alloy, which consists of plating, rinsing and drying, and then drawing the wire. (2) Continuously moving a wire made of titanium or titanium alloy in a straight line, shot blasting the wire to descale it, 0.5-20A/dm^
After applying alkaline electrolytic treatment at a current density of 2, washing with water, pickling, and washing with water, nickel with a film thickness of 20 to 60 μm is applied.
A method for continuous wire drawing of titanium or titanium alloy, which comprises applying plating treatment, once winding up the wire after washing and drying, and drawing the wire on another line.