JPH02211901A - Production of extremely fine titanium wire - Google Patents

Abstract

PURPOSE:To easily and inexpensively produce the extremely fine Ti wire having good quality by coating the outer periphery of Ti wire rods with a low-carbon steel strip, heating the wire rods at a specific temp., subjecting the wire rods to hot rolling at a specific temp. and then cooling the wire rods at a specific cooling rate. CONSTITUTION:The assembly of the coated wire rod formed by sticking a power mixture composed of mica and glass onto the surface of the Ti wire rods, then coating the outer periphery thereof with the low-carbon steel strip is used as an inside layer and the outside layer part is formed of the low-carbon steel. This billet is heated to <=1000 deg.C and is in succession subjected to the hot rolling at <=950 deg.C; thereafter, the wire rod is cooled at >=1 deg.C/sec cooling rate to obtain the wire rod in which plural pieces of the extremely fine Ti wire are included in obtd. The low-carbon steel part of this wire rod is thereafter dissolved away by using an acid. The extremely fine Ti wire having the good quality is easily obtd. in this way.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to titanium (hereinafter referred to as 'Ti
The present invention relates to a method for producing ultrafine wire (denoted as J) at low cost.

(Prior Art) Conventionally, as a method for producing ultrafine Ti wire, a Ti wire with an outer diameter of 5.5 mm, for example, produced by hot rolling is
As shown in Japanese Unexamined Patent Publication No. 62-185893, Ni plating was applied to the surface of a Ti wire, and this was used as a lubricating film, and the wire was drawn using a cold wire drawing machine. That is,
To make ultra-fine wire, pickling → annealing → pickling → Ni
It is necessary to repeat the process of plating → wire drawing. Therefore, this method requires many wire drawing steps, leading to high costs. Another method is to generate oxide scale on the Ti surface instead of Ni plating and use this as a lubricant for wire drawing, but this method also requires the process of pickling, annealing, and wire drawing to be repeated many times. However, the cost was high.

Furthermore, methods for manufacturing metal fibers using hot wire rolling are disclosed in 1) Japanese Patent Application Laid-Open No. 17163/1982 and 2) Japanese Patent Application Laid-Open No. 137623/1982.

Method (2) is to produce a billet for hot extrusion with an outer layer of ordinary steel and an inner layer of metal material for fiber, hot extrusion to form a billet for wire rod rolling, hot rolling of the billet, and an inner layer of Obtaining a composite wire with a metal material for fibers, the outer layer of which is made of common steel, and then hot extruding and hot wire rolling one or more times using the aggregate of the composite wire as the inner layer and the outer layer of common steel. It is disclosed as ``A method for manufacturing a wire containing a large number of thin metal wires for fibers'' and is described as a bundling rolling method. This method of cold-drawing a wire and then pickling it to produce fibers is thought to have lower manufacturing costs than the method of producing ultra-fine wires only by cold-drawing.

In addition, method ■ [In obtaining stainless steel long fibers,
A composite wire material is obtained by coating a stainless steel wire material with an ultra-low carbon steel strip with a carbon content of 0.008 wt% or less. A method for manufacturing stainless steel fiber, which comprises inserting the fiber into a thin carbon steel pipe, hot rolling it, repeating cold drawing and annealing to thin the fiber, and chemically removing the above-mentioned double-dimensional raw steel. , is characterized by wrapping an ultra-low carbon steel strip around the outer periphery of the metal wire to obtain a composite wire.

The above-mentioned Japanese Patent Application Laid-open No. 51-17163, Japanese Patent Application Laid-open No. 61-1
When manufacturing ultrafine stainless steel wire using the method disclosed in Publication No. 37623, it can be rolled under normal iron hot rolling conditions without any problems.
Further, by pickling the manufactured wire containing the stainless steel wire inside with an acid (nitric acid) that dissolves only iron, the stainless steel wire can be obtained.

(Problem to be solved by the invention) However, in the case of Ti wire, Ti and Fe easily form a low melting point compound (melting point 1070°C), so it cannot be used at normal hot rolling temperatures (1100°C or higher). A Fe-Ti compound is formed on the entire surface of the Ti wire. Moreover, this Fe-Ti compound dissolves in nitric acid, making it impossible to obtain ultrafine Ti wires. When hot rolling and winding are carried out at a higher temperature, Fe diffuses into the Ti, creating the same (Fe-Ti compound), and this compound dissolves in acid, making it impossible to obtain Ti ultrafine wires of a predetermined diameter. There is.

The present invention has been made in view of the above-mentioned problems.
The purpose is to provide a method for manufacturing ultrafine wires at low cost.

(Means for Solving the Problems) From the above viewpoint, the present inventors conducted various studies to find a manufacturing method and hot rolling conditions for a composite wire rod that does not easily generate Ti-Fe compounds, and as a result, they obtained the knowledge shown below. Ta.

(1) Ti cold-drawn wire rods with an outer diameter of around φ1 to 3fflIn are normally manufactured by drawing using hot-rolled wire rods with an outer diameter of φ5.5 mm, so lubrication and wire drawing can be performed only once or twice. Therefore, the cost is relatively low. Therefore, this wire material is used to make ultra-fine wires.

(2) Wrapping Ti wire drawn material with a low carbon steel strip can be used as a low-cost separator, but it cannot prevent the mutual diffusion of Ti and Fe. Therefore, if a diffusion preventive agent containing mica and glass is attached to the surface of the Ti wire drawn material and then the outer periphery is wrapped with a low carbon steel strip, there is a great effect of preventing diffusion between the copper strip and the Ti wire during hot rolling.

At this time, it is desirable to use oxidized scale for cold wire drawing in combination.

(3) R
The e-Ti compound layer can be kept within 10% of the outer diameter after rolling.

(4) After hot rolling or further wire drawing, an ultrafine wire can be obtained by pickling.

The present invention has been made based on the above findings, and is based on the first
The gist of the present invention is that the inner layer is a composite wire assembly in which a mixed powder containing mica and glass is adhered to the surface of a Ti wire and the outer periphery is covered with a low carbon steel strip, and the outer layer is made of a low carbon steel strip. After heating the steel billet at 1000°C or less and then hot wire rolling at 950°C or less, l'
A wire rod containing a plurality of Ti ultrafine wires is obtained by cooling at a cooling rate of c/sec or higher, and then the low carbon steel portion of the wire rod is dissolved and removed using acid.

The gist of the second invention is that, in the method of the first invention, a cold drawing process is interposed between the cooling process after hot wire rolling and the process of dissolving and removing the low carbon steel portion with acid. That's true.

(Function) The Ti wire in the present invention refers to α-phase Ti such as pure Ti, T
(α+β) type Ti alloy such as i-6AI-4V, Ti-3
AITi-3AI-8V-6Cr-4, Ti-15V
Refers to β-type Ti alloys such as -3Cr-3Sn-3AI.

In the method of the present invention, a wire having an outer diameter of about φ3M or less obtained by cold drawing the Ti alloy is used, and the cold drawing method is carried out using, for example, a roller die, a hole die, or the like. The oxide scale is then replaced with Ti as a lubricating base during wire drawing.
It is desirable to generate it on the surface of the material. This is because the scale acts as a lubricant and prevents diffusion into Fe0Ti, which is the separator.

In the present invention, a powder containing non-bonding mica and glass having a lubricating effect is dissolved in water and attached to the surface of the Ti wire drawing material and dried. This is because during hot rolling, mica and glass melt and cover the surface of the Ti wire, preventing diffusion of Ti and the outer low carbon steel strip as much as possible, and making it difficult to generate Fe-Ti compounds. It is. The components of the glass are not particularly limited, but it must be soluble in water and acid and have a melting point of 950°C or less. For example, SiO2, B, 0. Glass or the like having a melting point of 800° C. may be used.

The reason why the outer periphery of the Ti wire is coated with a low carbon steel strip is to prevent the Ti wires from fusing together.
Publication No. 7623 specifies that ultra-low carbon steel with a carbon content of 0.00ht2 or less is used. However, in the case of Ti wire, the diffused carbon combines with Ti on the surface of the Ti material, resulting in Ti
Therefore, the carbon content of the low carbon steel strip used in the present invention may be 0.1 wt% or less since it does not diffuse much into the Ti material.

For example, the method described in JP-A-137623 may be adopted as a method for coating the outer periphery of the Ti wire with a low carbon steel strip. However, at this time, in the present invention, a mixed powder of mica and glass, which is an anti-diffusion agent, is adhered to the surface of the Ti wire. The reason why a mixed powder of mica and water-soluble glass is used is that the mica prevents mutual bonding during rolling, and the glass provides lubrication. Note that sufficient diffusion prevention and non-bonding effects cannot be obtained with mica or glass alone. Also,
The glass used must be acid soluble. Further, the mixing ratio of mica and glass is not particularly limited, but for example, l
:1 is desirable.

When using oxide scale in addition to the mixed powder of mica and glass, it is preferable to heat it at 600 to 750° C. for 30 minutes, for example, and then air cool it in an atmospheric furnace, although it depends on the type of Ti alloy. At this time, the thickness of the oxide scale is 1 to 5μ
It is desirable to generate about m. Then, this composite wire rod is cut to a predetermined length, packed tightly into a low carbon steel pipe as an outer layer material, and the end is capped with a carbon steel plate by welding.
Hot rolling is performed. The carbon content of the carbon steel of the outer layer material may also be 0.1 wt% or less for the same reason as above.

Next, the reason for limiting the hot rolling conditions will be shown.

The heating temperature was 1000°C or less.
If the melting point of the Fe-Ti compound layer (107
0°C) and the Pe-Ti compound layer becomes very thick. The heating time at this time is preferably the shortest time in order to uniformly heat the billet.
Within hours.

By rolling, the wire diameter of the Ti wire becomes extremely small. However, the thickness of the Fe-Ti compound layer is a function of temperature and time, and as the wire diameter becomes smaller, the ratio of the Fe-Ti compound layer to the wire diameter increases, making it impossible to obtain ultrafine Ti wires. . Therefore, in the present invention, the rolling temperature is 9
The temperature was 50°C or less.

The rolling time is preferably within 2 to 3 minutes, for example at 880°C.
After heating at 830°C, rolling ratio 1OO1 rolling time 3
The thickness of the Fe--Ti compound layer was 5 .mu.m when the sample was cooled at 2.degree. C./sec. In the case of rolling at 950°C or higher, even if the rolling time is shortened and the cooling rate after rolling is increased,
It is difficult to suppress the Fe-Ti compound layer to 10 μm or less.

The reason why the cooling rate after hot rolling is set to I'C/sec or more is that below this rate, the time in which Fe diffuses into Ti at a high rate becomes longer, so the FeTi compound layer becomes thicker. This is because ultrafine Ti wires with good surface roughness and dimensional accuracy cannot be obtained.

A composite hot rolled wire rod having an outer diameter of approximately φ5.5 to 10 mm is obtained by the above-described hot rolling. Then, the low carbon steel as the separator and the diffusion inhibitor are dissolved in this wire using acid to obtain a Ti ultrafine wire with an outer diameter of about 100 to 200 μm.

Note that the type of acid is preferably nitric acid. This is because only iron is dissolved, and Ti is not dissolved. The concentration of nitric acid is 20
~40% is desirable. If it is less than 20%, the dissolution ability is poor;
This is because a long pickling time is required. Moreover, if it is 40% or more, the liquid will easily boil during the dissolution reaction, which poses a safety problem. The treatment temperature is 50°C because dissolution reaction poetry tends to boil if it exceeds 50°C, which poses a safety problem.
The following are desirable.

In order to obtain a thinner Ti wire, the hot rolled composite wire is cold drawn. If the wire is drawn to an outer diameter of approximately 1 mm,
A T1 ultrafine wire with an outer diameter of about 10 μm is obtained.

At this time, annealing is performed several times, but the annealing temperature and time are F
In order to prevent the expansion of the e-Ti compound layer, the temperature is preferably 700°C or less and 2 hours or less.

(Example 1) Outer diameter φ2, Omm after cold drawing with roller die
Pure Ti wire A and wire material B were coated with a diffusion preventive agent (for example, White Lube 8A (trade name)), which is a powder mixture containing 50% mica and 50% glass, dissolved in water and dried. , and their outer periphery is 0.4 mm thick.
Using a single-head wire drawing machine using a rimmed steel strip with a width of 11 mm,
A coating process was performed continuously to obtain a composite wire with an outer diameter of φ3.5. Note that pure Ti wire A is a comparative example.

The chemical composition of pure Ti wire and rimmed steel strip is shown in Table 1 below.
．． Shown in 2.

After straightening the composite wire, it was cut into 3 m pieces. Next, 140 low-carbon copper tubes with an outer diameter of 135 mm and an inner diameter of 50 mm were packed, the ends were capped with low-carbon steel plates, and two hot-rolled billets were made. Table 3 shows the chemical composition of low carbon steel pipes.

Then, after heating at 900°C for 2 hours, they were hot rolled at 850°C, and wire rods A" and Bo with an outer diameter of φ9.5, 85
It was cooled by air cooling between 0 and 500°C at a rate of 3°C/second. Outer diameter φ
From the microstructure of the cross section of a 9.5 mm wire, Ao and B
'The diameter of the Ti wire in the composite wire is approximately 140 μm, and the diameter of the Ti wire in the composite wire is approximately 140 μm.
-The thickness of the Ti compound layer was 7 μm in Comparative Example A′ and 3.0 μm in Inventive Example B′, and by using Material B of Inventive Example whose surface was coated with a diffusion inhibitor, the compound layer was extremely thick. Can be made thinner.

In addition, A' and B' composite wires were processed at a temperature of 45°C and 140%.
By pickling with nitric acid, about 120 μm from Ao and B
A pure Ti line of about 130 μm was obtained.

Table 1 (unit: t%) Table 2 (unit: wt%) Table 3 (unit: wt%) (Example 2) After cold drawing the A゛ composite wire of Example 1 to an outer diameter of φ4 mm After annealing at 680°C for 1 hour and further cold drawing to an outer diameter of φ2M, annealing at 680°C for 1 hour and further cold drawing to an outer diameter of φ1. Next, pickling was carried out under the same pickling conditions as in Example 1, and the outer diameter was 14 μm.
140 pure Ti ultrafine wires were obtained.

The diffusion inhibitor and Fe-Ti diffusion layer are removed by pickling.

(Example 3) Fe-Ti compound layer when the hot-rolled billet using the B' pure Ti wire of Example 1 was rolled into a wire rod with an outer diameter of φ9.5 by varying the hot rolling conditions. Table 4 shows the results of measuring the thickness.

The heating time was 2 hours, the rolling time was 2 to 3 minutes for Nos. 1 to 7, and 10 minutes for Nos. 8. As shown in Table 4, in the inventive example, the thickness of the Fe-Ti compound layer was thin and it was possible to make a good Ti ultra-fine wire, but in the comparative example, the Fe-Ti compound layer was thick and the Ti ultra-fine wire was able to be made. The surface roughness was poor, and the yield was also poor.

An excellent effect is obtained in that the excellent Ti ultrafine wire shown in Table 4 can be manufactured easily and at low cost. Therefore, it can be applied to chemical filters, fibers for composite materials, etc.

In addition, in the above explanation, a Ti wire using cold drawing is explained, but not only this but also cold drawing,
A Ti wire rod having a diameter of approximately 1 to 3 g may be manufactured by hot cutting of the outer diameter.

(Effect of the invention)

Claims (2)

[Claims] (1) A billet whose inner layer is an aggregate of composite wires made by adhering a mixed powder containing mica and glass to the surface of a titanium wire rod and then covering the outer periphery with a low carbon steel strip, and the outer layer is made of low carbon steel. was heated to 1000℃ or less, and then heated to 950℃.
After hot-rolling the wire rod at a temperature of 1°C or lower, the wire rod is cooled at a cooling rate of 1°C/sec or higher to obtain a wire rod containing multiple ultrafine titanium wires, and then the low carbon steel portion of the wire rod is heated with acid. 1. A method for producing ultrafine titanium wire, which comprises dissolving and removing the titanium wire. (2) In the method according to claim 1, a cold drawing step is interposed between the cooling step after hot wire rolling and the step of dissolving and removing the low carbon steel portion with acid. Production method.