JPH04147712A - Manufacture of noble metal clad titanium wire rod - Google Patents

Abstract

PURPOSE:To simplify the blank material assembling by assembling the multi- laminated clad bland material with using the core material of Ni plated Ti core material, hot-extruding, then cold working for diameter reducing, removing the most outer layer by dissolving with acid and finish-drawing the wire rod. CONSTITUTION:Ni plated Ti core material 2 is inserted in the noble metal tube 3, and these is inserted in the steel tube 4, then inside of the tube is de- gassed, both ends are close sealed with the cap components 4a, and the multi- laminated clad blank material 5 is assembled. This blank material 5 is hot extruded and is made to the multi-laminated clad material. This multi-laminated clad material is cold worked to reduce diameter. The steel of most outer layer is removed by dissolving with acid. After removing the most outer layer, it is subjected to finish-drawing with die. On the drawing process, the die drawing of the section reduction rate <=50% and the softening annealing are repeatedly executed. Therefor, the jointing property can be improved remarkably.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a noble metal clad titanium wire rod, in which a core material made of titanium or a titanium-based alloy is coated with a noble metal such as gold or a gold-based alloy. It is something.

[Conventional technology]

Precious metals such as gold, silver, or alloys thereof are used as materials for ornaments, arts and crafts, or coating materials.

In cases where gold or gold-based alloys are used as coating materials, they are supplied as composite materials in which the surface of the relatively inexpensive metal material (core material) is coated with precious metals. For example, stainless steel, nickel silver, etc. so that the aesthetic appearance is not compromised.

Ni-Cr alloys, etc. have been used (Special Publication Act
Publication No. 268).

Recently, a composite material has been proposed as a material for eyeglass frames, in which the core material is titanium wire, which is lightweight and has excellent corrosion resistance and workability, and the outermost layer is a precious metal (Japanese Patent Application Laid-Open No. 60-149789, Japanese Patent Application Laid-Open No. 63-78741), in order to increase the bonding strength at the bonding interface when titanium is directly coated or plated with a noble metal, nickel alloys or Nb and Ni or Ni-based alloys are used as intermediates. The material is a composite material with multiple layers.

Although this composite material has certain advantages,
Because it has a three- or four-layer multilayer structure, its manufacture is complicated and it is not suitable for mass production. As a method to solve this problem, a method has been proposed in which a composite material is manufactured by directly diffusion bonding the noble metal and the core material titanium using hot isostatic extrusion (Japanese Patent Laid-Open No. 61-43717). Publication, Japanese Patent Application Laid-Open No. 6233079).

[Problem to be solved by the invention]

However, for eyeglass frames, high-quality processing is essential, such as formation of lens grooves, 1. swaging and press processing of flat cross-sectional shapes for facial support; 1. However, since local heating due to brazing is unavoidable when assembling each component, the bonding strength at the bonding interface, especially at the interface between titanium and other metals, was not sufficient for manufacturing eyeglass frames.

The present invention was made in view of the above circumstances, and its purpose is to improve the bondability between the core material of titanium or titanium-based alloy and the noble metal such as gold or gold-based alloy that covers it, and to achieve high To provide a method for efficiently producing a precious metal craft titanium wire at a low cost and capable of withstanding local heating of a working degree of 1.

[Means to solve the problem]

The first method for producing a noble metal clad titanium wire according to the present invention is to insert a core material made of nickel-plated titanium or a titanium-based alloy into a noble metal pipe, and then insert the core material into a steel pipe, and then insert the core material into a steel pipe. a step of deaerating the material and sealing both ends to produce a multi-clad material; a step of subjecting the multi-clad material to stretching processing by hot extrusion or hot isostatic extrusion to produce a multi-clad material; The process includes the steps of reducing the diameter of the multi-clad material by cold working, removing the outermost layer of steel by dissolving it in acid, and after removing the outermost layer, finishing wire drawing with a die. Features.

Further, in the second method for producing a noble metal crund titanium wire according to the present invention, the nickel-plated titanium or titanium-based alloy core material is formed by electrolytically polishing the surface of a titanium bar material,
It is formed by nickel plating after activation with nitric acid.

Furthermore, the third method for manufacturing a noble metal talano titanium wire according to the present invention includes, in the wire drawing step of the multi-clad material from which the outermost layer is removed, die wire drawing with an area reduction ratio of 50% or less and softening annealing. Do it repeatedly.

[Effect]

In the present invention, by using a nickel-plated titanium core material with high bonding strength, the cladding material can be easily assembled, and strong bonding strength can be obtained as a composite material.

〔Example〕

The present invention will be specifically explained below based on the drawings.

FIG. 1 is a block diagram showing the main manufacturing steps according to the method of the present invention. In the method of the present invention, a Ti (titanium) or Ti-based alloy bar 1 is plated with Ni (nickel), and N
Obtain the i-metallic Ti core material 2, insert it into a separately prepared noble metal pipe 3, and further insert it into a carbon mesh pipe 4 to deaerate the inside of the carbon steel pipe 4, then seal both ends and assemble the multi-clamp material 5. Process (Step St) and this multiple clad material 5
After heating the material to a predetermined temperature (step S2), a process of forming a multi-clad material 6 by stretching by hot extrusion (step S3), and a step of forming the outer diameter of the formed multi-clad material 6 by cold working. A step of drawing the outer diameter (reducing the diameter) to obtain the composite material 7 (step S4), and a step of dissolving and removing the outermost carbon steel layer of the composite material 7 with acid to obtain the composite material 8 (step S5).
) and a step (step S6) of final wire drawing (diameter reduction) of the composite material 8 from which the carbon steel layer has been removed using a finishing die to obtain a noble metal clad titanium wire rod 9.

Each step will be explained below.

(1) Production process of Ni-plated Ti core material Ti or Ti
After electrolytically polishing the outer peripheral surface of a Ti bar 1 formed using a base alloy, the surface is activated with nitric acid and Ni plating is applied.

As Ti or Ti-based alloy, Ti alone or mainly composed of Ti, Ti and A1, Mn, Fe, Cu, Mo
, Cr, W, etc., and the Ti content in the alloy is preferably 90% (wt%, hereinafter the same shall apply unless otherwise specified). Note that if it is less than 90%, the specific gravity will increase and the characteristics as a light metal will be impaired.

The reason for using a Ti or Ti-based alloy bar with Ni plating on the Ni-coated Ti core material is to activate the outer peripheral surface of the Ti or Ti-alloy bar and then apply Ni plating to create a Ni-coated material with excellent bonding strength. This is because a Ti bar material can be obtained and a Ni layer of any thickness can be efficiently obtained simply by controlling the plating time.

A comparative test was conducted regarding the bondability between the Ni plating and the Ti core material between samples produced under the above conditions and samples produced under other conditions.

The test was conducted using a wire made of pure Ti (JIS Class 2) with an outer diameter of 2 fl and a length of 15 mm as the Ti material.
Under the conditions of ■, the outer peripheral surface was plated with Ni and T.
The zygosity with i was investigated.

■ After electropolishing the outer peripheral surface, the surface was activated with nitric acid.

■ After pickling, degreasing and washing were performed.

■ The outer surface was polished with a grinder.

Plating was performed under the above conditions, and the bondability between Ni and Ti was evaluated in a torsion test using the obtained Ni-plated Ti wire.

Note that the Ni plating film thickness was 10 μm. For the torsion test, both ends of the wire are fixed with chucks, one end is rotated 3 times, and then the wire is rotated 3 times.
This was done by rotating it back.

The results show that the plating on the Ni-plated Ti wires obtained under the conditions ■ and ■ peeled off after the first half turn, but the plating did not peel off on the Ni-plated Ti wire obtained under the conditions ■ even after three rotations and three rotations. It was in good condition with no peeling.

From this, it was found that by activating the Ti surface after electrolytic polishing, a Ni-plated Ti rod with excellent bonding strength could be obtained.

(2) Multiple cladding material assembly process (step Sl) 2nd
The figure is a schematic diagram showing the state of assembly of a multi-clad material, in which a Ni-plated Ti core material 2 obtained by applying Ni plating to a Ti or Ti-based alloy bar material 1 is made of gold or a gold-based alloy, etc. After inserting it into the noble metal pipe 3 and further inserting it into the carbon steel pipe 4, the inside of the carbon steel pipe 4 is deaerated, a carbon steel cover member 4a is fitted to both ends, and the entire circumference is welded to the carbon steel pipe 4. Obtain multiple crafting material 5.

The reason why Ni-plated Ti core material 2 is used as the core material is that when diffusion bonding is performed in the subsequent process, it is actually better to bond three layers than to bond four or more layers. This is because a multi-clad material 6 having excellent bonding strength can be obtained.

The reason why a carbon steel pipe and a carbon steel lid 4a are used as the outermost layer is as follows.
This is because these layers are removed by acid dissolution in a later step, so ease of acid dissolution and low cost were taken into consideration. From the viewpoint of ease of acid dissolution, copper or copper alloy may be considered, but it is not easy to weld hermetically when assembling the cladding material 5, and even if it is sealed by brazing, it will be difficult to use in the subsequent process. Since it is heated to around 800 degrees Celsius, the seal will be compromised for the first time when the brazing part melts.

(3) Hot extrusion process of multi-clad material (Step S3)
) The multi-clad material 5 is heated to a predetermined temperature and then stretched using an extrusion device 10 as shown in FIG. This is because since this is an axially symmetrical processing method, variations in the thickness of the noble metal layer are suppressed and diffusion bonding between metals can be efficiently performed.

FIG. 3 is a schematic diagram showing the extrusion state by the extrusion device 10 used in the present invention. The extrusion device 10 includes a container 11, a punch 12, and a die 13.

After the multi-clad material 5 is heated to a predetermined temperature, it is coated with sapphire, placed in a container 11, pressurized by a punch 12, and extruded to a target outer diameter by a die 13. Multiple crund materials 6 are obtained which are mutually diffusion bonded.

Note that the same effect can be obtained by using hot isostatic extrusion instead of hot extrusion.

(4) Cold outer diameter drawing step (Step S4) In the hot extrusion step of the previous step, the outer diameter is reduced to 1 (ti) based on the normal equipment capacity.
Since it is difficult to extrude to a size smaller than n, the outer diameter is reduced by cold working.

FIG. 4 is a schematic diagram showing a state of cold wire drawing using the die 21, and a composite material 7 is obtained by cold drawing the multiple kraft material 6 obtained by hot extrusion. Since the die 21 is used in an axially symmetrical processing method, it is possible to minimize variations in the thickness of each layer during processing, and the outermost layer of the composite material 7 is made of a carbon steel layer, making it possible to suppress variations in the thickness of each layer during cold processing. This is because the noble metal layer can be prevented from being damaged. Although a groove rolling method or a roller die wire drawing method may be used in this cold outer diameter drawing step, the die wire drawing method is preferable in terms of suppressing variations in the thickness of each layer as much as possible as described above.

In this die wire drawing method, a composite wire 8 is obtained by sequentially reducing the outer diameter of the composite material 7 using a large number of dies.

(5) Carbon steel layer removal step (Step S5) Composite material 7 obtained in the previous step is pickled and the outermost carbon steel layer is dissolved and removed to obtain composite material 8 with exposed noble metal layer. . The reason why the carbon steel layer is removed by pickling is that the precious metal layer is very thin, and machining may remove even the precious metal layer.Also, as the outer diameter becomes thinner, it is difficult to remove the outer surface by machining. By becoming.

(6) Finishing die wire drawing step (Step S6) Finishing die wire drawing is performed to smooth the surface of the composite material 8 obtained in the previous step and to give it a noble metal luster.

In this die wire drawing process, a large number of dies are used to sequentially reduce the outer diameter of the composite material 8, but if the die wire drawing is performed with an area reduction rate exceeding 50%, small cracks will occur on the surface of the precious metal layer. , after drawing with an area reduction rate of 50% or less, 500℃~70℃
By repeating the process of softening and annealing at 0° C., a good noble metal clad titanium wire 9 with no cracks in the noble metal layer can be obtained.

[Test example]

Gold-clad titanium wire rods were manufactured using the following two types of multilayer kraft materials and evaluated.

Material I (Material not used in the present invention) Low carbon aluminum killed steel pipe diameter 67WM±0.1 Inner diameter 600: f! -"Gold-based alloy tube (12, 50%Au -40%Cu-6%N
i-4%Zn) Outer diameter 60ta±0.1 Wall thickness 0.6
m Pure Ni tube (Ni 200) Outer diameter 58.5 mm ±0.1 Inner diameter 52 tm ::・2
Pure Ti rod (JIS Class 2) Diameter 52m: g, z Material ■ (Material used in the present invention) Low carbon aluminum killed steel pipe diameter 671u ± 0.1 Inner diameter 60w 2g-z gold-based alloy pipe (12, 50% Au 40%Cu-6%N
i-4%Zn) Outer diameter 60 Tsuru ±0.1 Wall thickness 0.6f
lNi plated Ti core material (metallic thickness = 3 cranes, Ti: JIS
Type 2) Material with diameter 58.5m ± 0.1 and length 185mm 1. n (2~3) x 10
A multi-clad material as shown in FIG. 2 was fabricated by electron beam welding both ends in a -' Torr vacuum chamber.

Next, material 1. After heating II to 800°C, it was hot extruded to a diameter of 25 fl (extrusion ratio = 7.
The multi-clad material 6 of 2) was extruded.

The bonding strength of this multiple clad material 6 was evaluated by a shear test method as shown in FIG.

FIG. 5 is an explanatory diagram showing an example of the cross-sectional shape and dimensions of the sample and jig used in the shear test. Figure (C1 shows the test mode. The sample 30 is a multi-clamp material 6 with a length h+w
The carbon steel tube, the gold-based alloy tube, and the Ni layer were removed within the range of length W, and the Ti bar was also thinly cut to form a cylinder with a diameter of d2.

On the other hand, the jig 31 is configured such that the inner diameter of one end of the tube material is D2 over a predetermined length, and the inner diameter of the other end is dz (Dz>dS). A sample is inserted into the large diameter end of the jig 31 as shown in FIG. I asked for it.

The bonding strength is 14 kgf/mm when using material 1 and 23 kgf/ms when using material ■.
It was found that the multi-clad material 6 has superior bonding strength.

Next, material 1. The multiple cladding material 6 with a diameter of 25++n obtained from both n and 25 + n is reduced in diameter by die wire drawing to a diameter of 7.0~
The composite material 7 was 7.2 m long. Softening annealing was performed at 570° C. for 10 minutes while changing the area reduction rate per die die in four stages in the range of 10 to 15%. After drawing the wire to a diameter of 7 In, remove the outermost carbon steel layer with nitric acid, and then
2, the state of the layer was observed. The result is material 1. Table 1 shows the schedule for II.

In Table 1, ○ indicates good surface quality, Δ indicates cracks have occurred on the surface.
The X mark indicates that the layer was broken at 12.

As is clear from Table 1, it was found that a good gold-clad titanium wire could be obtained by using material (2).

Next, material ■ was reduced in diameter by repeating die wire drawing and softening annealing according to dimension schedule 1, and then a diameter reduction process was performed by finishing die wire drawing using a composite wire rod with a diameter of 6.3 mm with the outermost layer material removed. did.

At this time, the area reduction rate per die is 1 as before.
0 to 15%, and softening annealing was performed at 570°C for 3 minutes.

Then, the area reduction rate up to softening annealing was changed in four stages. Table 2 shows the evaluation of No. 12 at that time along with the dimensional schedule. As is clear from Table 2, it was found that a good gold thalassodium titanium wire rod could be obtained if softening annealing was performed with the reduction in area kept at 50% or less after carbon steel was removed.

Note that a gold thalassodium titanium wire manufactured using material (■) according to a dimensional schedule of 1.5 was processed into an eyeglass frame member, and then the eyeglass frame was assembled. There were no problems such as layer loss during processing into eyeglass frame members, and there were no problems such as peeling of the joint interface during brazing during frame assembly, and a good eyeglass frame could be assembled.

〔effect〕

As described above, in the present invention, a multi-clad material is assembled using a Ni-plated Ti core material, and by hot extrusion,
After diffusion bonding, the diameter is reduced by cold working, and further diameter reduction by die wire drawing method with an area reduction rate of 50% or less and softening annealing are repeated to obtain a noble metal clad titanium wire. Of course, the material assembly can be simplified because of the
The present invention has excellent effects such as significantly improved bondability.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the main manufacturing process of the present invention;
The figure is a schematic cross-sectional view of the multilayer kraft material used in the present invention, Figure 3 is a schematic diagram of the hot extrusion process in the method of the present invention, Figure 4 is a schematic diagram of the die wire drawing process using the method of the present invention, and Figure 5 is a schematic diagram of the die wire drawing process using the method of the present invention. The figure is an explanatory diagram showing a shear test mode. 1...Ti bar material 2...Ni-plated Ti core material 3.
...Precious metal pipe 4...Carbon steel pipe 4a...Lid member 5...Multiple clad material 6...Multiple clad material 7...Composite material 8...Composite material 9...Precious metal clad titanium wire rod 10... Extrusion device 11... Container 12... Punch 13... Dice 21...
・Dice patent applicant

Claims (3)

[Claims] 1. After inserting a core material made of nickel-plated titanium or titanium-based alloy into a tube made of a precious metal, and then inserting these into a steel tube, the inside of the steel tube is evacuated and both ends are sealed. A process of producing a multi-clad material, a process of stretching the multi-clad material by hot extrusion or hot isostatic extrusion to obtain a multi-clad material, and shrinking the multi-clad material by cold working. A process for manufacturing a precious metal clad titanium wire rod, comprising: a step of removing the outermost layer of steel by acid dissolution; and a step of finishing wire drawing with a die after removing the outermost layer. Method. 2. The noble metal clad titanium according to claim 1, wherein the nickel-plated core material made of titanium or titanium-based alloy is formed by electrolytically polishing the surface of a titanium rod, activating it with nitric acid, and then applying nickel plating. A method of manufacturing wire rods. 3. 2. The method for producing a noble metal clad titanium wire rod according to claim 1, wherein in the step of drawing the multi-clad material from which the outermost layer of steel has been removed, die wire drawing with an area reduction rate of 50% or less and softening annealing are repeatedly performed.