JPH04111981A - Production of noble metal clad titanium wire - Google Patents

Abstract

PURPOSE:To efficiently produce the noble metal clad titanium wire at a low cost by assembling a multiclad blank material by using an Ni-clad Ti core material by fitting and subjecting this blank material to vacuum hermetic closing, then subjecting the material to hot extrusion, diffusion joining and diametral reducing by cold working, and then removing the copper layer by acid dissolution. CONSTITUTION:The clad titanium wire 10 is obtd. by a stage A for inserting a bar material 1 made of Ti or Ti-based alloy into a pipe 2 made of Ni or Ni-based alloy and hermetically closing both ends to assemble the two-layered clad blank material 3, a heating stage B for heating this clad blank material 3 to a prescribed temp., a stage D for obtaining the Ni-clad Ti bar material 4 diffusion-joined between each via a hot working stage C and further, inserting this material into a carbon steel pipe 6 and hermetically closing both ends to assemble the clad blank material 7, a heating stage E for heating the material to a prescribed temp., a stage G for reducing, by cold working, the outside diameter of the composite material 8 formed via a stage F for drawing the material by hot rolling, a stage H for removing the carbon steel layer on the outermost layer thereof by acid dissolution, and a stage I for subjecting the composite wire 9 after the removal of the carbon layer to finish die drawing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for producing a noble metal clad titanium wire rod in which a core material of Ti (titanium) or a titanium-based alloy is coated with a noble metal such as gold or a full-base alloy. It is related to.

[Conventional technology]

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

Here, when gold or all-based alloys are used as a coating material, they are supplied as a composite material in which the surface of a relatively inexpensive metal material (core material) is coated with a precious metal (Japanese Patent Publication No. 60-38
No. 268). As the core material used in such composite materials, stainless steel, nickel silver, Ni-Cr alloy, etc. have been used, for example, so that the aesthetic appearance is not impaired even if the precious metal is peeled off.

Recently, as well as being lightweight as a material for eyeglass frames,
Titanium wire rods with excellent corrosion resistance and workability have become widespread, and a composite material in which the core material is a titanium wire rod and the outermost layer is a precious metal has been proposed as a material for eyeglass frames (Japanese Patent Application Laid-open No. 149789/1983). (No. 78741, 1983).

However, when titanium is directly coated or plated with precious metals,
There was a problem in that the bonding strength at the bonding interface was insufficient and could not withstand processing into an eyeglass frame member. In order to improve this joint strength, Ni-based alloy or Nb and N
A composite material with a multiple structure using an i- or N1-based alloy as an intermediate material has been proposed.

By the way, although a titanium core composite material has a certain degree of horizontal property, it is difficult to manufacture because of its three- or four-layer multilayer structure, 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 produced by directly diffusion bonding the noble metal and the core material titanium using hot isostatic extrusion (Japanese Patent Laid-Open No. 61-437
No. 17, JP-A-62-33079).

However, in order to manufacture eyeglass frames, high-quality processing is essential for forming eyeglass frames, such as forming lens grooves, swaging and pressing of flat cross-sectional shapes for facial support, and each component is ■Local heating due to brazing is unavoidable when standing.

There has not been a sufficient solution to problems such as peeling at the bonding interface, especially the lack of bonding strength at the interface between titanium and other metals.
It was not sufficient as a material for eyeglass frames.

[Problem to be solved by the invention]

However, there is still no method for efficiently producing at low cost a composite material having a bonding interface that can withstand high processing and local heating as a material for eyeglass frames.

An object of the present invention is to provide a method for efficiently producing a noble metal clad titanium wire rod at low cost, in which a core material of titanium or a titanium-based alloy is coated with a noble metal such as gold or a full-base alloy.

[Failure to solve the problem]

The method for manufacturing the noble metal clad titanium wire according to the present invention is T
In a method for producing a noble metal clad titanium wire, the core material made of Ti or Ti-based alloy is coated with an outer layer material of a noble metal,
A step of diffusion bonding Ni or Ni-based alloy to the circumferential surface of the core material by hot working to form a two-layer clad material, and inserting the two-layer clad material into a pipe made of a precious metal, and further inserting it into a steel pipe. After that, the inside of the steel pipe is degassed and both ends are sealed to produce a four-layer clad material, and the four-layer clad material is stretched by hot extrusion or hot isostatic extrusion to form a four-layer clad material. A step of forming a clad material, a step of reducing the diameter of the four-layer clad material by cold working, a step of removing the outermost layer of steel by acid dissolution, and a step of finishing wire drawing by die wire drawing. It is characterized by including.

In addition, the method for producing a noble metal clad titanium wire according to the present invention further includes hot inclined rolling of N1 or N1-based alloy on the circumferential surface of the core material using an inclined rolling mill having three or four cone-shaped rolls. It is characterized by including a step of diffusion bonding to form a two-layer cladding material.

[Effect]

In the present invention, a two-layer cladding material is first formed by diffusion bonding N1 or Ni-based alloy to the circumferential surface of a core material made of Ti or 11-based alloy by hot working, so that mutual bondability is improved. In addition, the outermost layer forms a four-layer clad material of steel pipes and is subjected to drawing processing and cold working by hot extrusion, etc., which prevents damage to the surrounding surface of precious metals.Moreover, since the steel is removed by acid dissolution, the inside The surface of the layer is not damaged.

〔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. First, a bar material 1 made of Ti or Ti-based alloy is
Step (A) of assembling a two-layer cladding material 3 by inserting it into an i- or Ni-based alloy tube 2, vacuum degassing the inside of the tube, and sealing both ends, and heating this cladding material 3 to a predetermined temperature. Through the heating process (B) and the hot working process (C), a Ni-clad Ti bar 4 is obtained which is bonded to each other by diffusion, and this Ni-clad Ti bar 4 is inserted into a noble metal pipe 5, and then a carbon steel pipe is formed. 6 and vacuum degassed the inside of the carbon steel pipe 6,
Step of assembling the crand material 7 by sealing both ends (D)
Then, a composite material 8 is formed through a heating step (E) of heating this crand material 7 to a predetermined temperature and a step (F) of stretching by hot extrusion, and the outer diameter of the formed composite material 8 is cooled. A step (G) of drawing the outer diameter during preliminary processing, a step (I) of removing the outermost carbon steel layer by acid dissolution, and a finishing die elongation of the composite wire 9 after the carbon steel layer has been removed. A clad titanium wire 10 is obtained through the step of wire (1).

Each step will be explained below.

(1) Assembly process of the two-layer clad material 3 FIG. 2 is a sectional view of the two-layer clad material 3 used in the present invention.

A core material 13 made of Ti or Ti-based alloy bar material 1, and N
After degreasing and cleaning both metal materials, the core material 13 is inserted into the outer layer material 11, and the inside of the outer layer material 11 is made of I Xl0-.
After degassing until the degree of vacuum is below Torr, the two-layer cladding material 3 is sealed at both ends with a cover material 12 made of the same material as the outer layer material 11 by welding, and the above degree of vacuum is maintained. Manufacture. In addition, the core material 13 and the outer layer material 11
By interposing another metal as an intermediate material between the two, a multilayer structure clad material having three or more layers can be obtained.

The reason why the degree of vacuum is set to I This is because it decreases.

Here, Ti or Ti-based alloys include Ti alone or Ti as a main component, and Ti and L V, Mn, Fe, Cu,
Mo, Cr.

It includes an alloy with one or more components such as W, and the TI content in the alloy is preferably 90% (wt%, the same shall apply hereinafter unless otherwise specified) or more. 90%
This is because if it is less than that, the specific gravity will increase and the characteristics as a light metal will be impaired.

In addition, Ni or Ni-based alloys include Ni alone or Ni as a main component, and Ni and Cr, Cu, Fe, Ag, Si.
, S, Pb, Pt, Au, rare earth element, T
i, Nb, 11/! , Mo, Sn, Go, etc.
This includes species or alloys with two or more species.

(2) Heating process B of the two-layer cladding material 3 The two-layer cladding material 3 obtained through the above-mentioned assembly process is heated to the core material 13. A temperature lower than the melting point of the outer layer material 11 (intermediate material if there is one) and the melting point of these intermetallic compounds, for example 850°C
Heat to the following temperature.

(3) Hot working step C using an inclined rolling mill In the hot working step C, elongation rolling is carried out using an inclined rolling mill having three or more cone-shaped rolls as shown in Fig. 3.4.5. This is because in an inclined rolling mill having two rolls, a so-called Mannesmann fracture phenomenon occurs, and cracks occur in the center of the rolled material.

As the inclined rolling mill, it is desirable to use a cross-type inclined rolling mill.

FIG. 3 is a front view showing the rolling state by the inclined rolling mill 20 used in the present invention, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a direction taken along line V-V in FIG. 3. FIG. The inclined rolling mill 20 has three cone-shaped rolls 21, 22, 23 facing around the pass line, and the three rolls 21, 22, 23 have a gorge at a position near the exit end of the two-layer crund material 10. The two-layer clad material 3 has sections 21a, 22a, and 23a, and the diameter of the inlet side of the two-layer clad material 3 is gradually reduced toward the shaft end with the gorge sections 21a, 22a, and 23a as boundaries, and the outlet side is enlarged to form a truncated cone shape. Eggplant entrance surface 21b
, 22b, 23b and exit surfaces 21c, 22c, 23
The exit surfaces 2Lc, 22c, and 23c have distances from the pass line to the gorge portions 21a, 22a, and 23a.
and the distance between the path line XX and the pass line XX. These cone-shaped rolls 21, 22, and 23 all have their artificial faces 21b, 22b, and 23b positioned upstream in the direction of movement of the two-layer clad material 3, and have Y-axis along their axis.
The intersection point O between Y and the plane including the gorge parts 21a, 22a, and 23a (hereinafter referred to as the roll setting center) is connected to the bus line XX on the same plane orthogonal to the pass line XX of the two-layer cladding material 3. They are arranged at approximately equal intervals around the circumference. And the axis YY of each roll 21, 22, 23
is the intersection angle γ around the roll setting center O, in relation to the pass line XX of the two-layer cladding material 3, so that the front shaft end approaches the pass line XX as shown in FIG. As shown in FIGS. 4 and 5, the front shaft ends are inclined toward the same side in the circumferential direction of the two-layer clad material 10 by an inclination angle β.

The crossing angle T and the inclination angle β are o'<γ<15°, 3°<β<
Set so that 20° and 5° satisfy γ+β<30°.

Each roll 21, 22, 23 is connected to a drive source (not shown) and is driven to rotate in the same direction as shown by arrows in FIG. 3 is elongated and rolled while being rotated between its axes and moved in the axial direction, ie, so-called spiral movement.

While the layered cladding material 3 is spirally moved between rolls, its outer diameter is reduced at the roll bite portion R as shown in FIG. After the rolled surface U of the two-layer cladding material 3 is formed into a truncated conical shape, the gorge portion 21a is formed.

22a, 23a, exit surface 21c, 22c, 23c
It is processed into an N+ clad T1 bar 4 which is a layered clad material with a circular cross section.

In the present invention, the reason why an inclined rolling mill having three or more cone-shaped rolls is adopted to elongate and roll the two-layer crund material 3 to obtain the Ni-clad Ti bar 4, which is the two-layer crund material, is as follows. That's right.

Hot stretching methods other than inclined rolling using this inclined rolling mill include forging, groove rolling, isostatic extrusion, etc.
These methods are not only inferior to the above-mentioned inclined rolling in terms of bonding strength at the bonding interface and uniformity of the outer layer material, but also when the difference in deformation resistance between the outer layer material and the inner layer material such as the core material is large, both materials An unbonded portion remains between them, and this will remain as an unbonded portion even when the multilayer composite material 8 is formed. If there is an unjoined portion in the multilayer composite material 8, when the composite material 8 is used for an eyeglass frame, good joining performance cannot be maintained during processing into an eyeglass frame member due to the unjoined portion.

Therefore, an inclined rolling mill is used, which has high bondability between the two materials, excellent bonding strength at the bonding interface, and uniformity of the thickness and shape of the outer layer material.

(4) Clad material 7 navy blue standing process FIG. 6 is a schematic cross-sectional view showing the assembled state of the clad material 7, in which a core material made of Ti or Ti-based alloy is coated with an outer layer material made of Ni or Ni-based alloy. Diffusion bonded Ni clad T
i Insert the bar material 4 into the noble metal pipe 5, and then insert it into the carbon steel pipe 6.
After the carbon steel pipe 6 is inserted into the carbon steel pipe 6, the inside of the carbon steel pipe 6 is degassed, and a cover member 14 made of carbon steel is welded to the entire circumference of the carbon steel pipe 6 at both ends to obtain a cladding material 7. The inside of the carbon steel pipe 6 is I Xl0-'Tor
Maintain the degree of vacuum below r.

The reason why the Ni-clad Ti rod 4 is used as the core material is that when diffusion bonding is performed in a later process, the bonding strength is substantially higher when three layers are bonded than when four or more layers are bonded. This is because a composite material 8 having excellent properties can be obtained. and,
Ni in this Ni-clad Ti bar 4 (outer diameter = D)
It is desirable that the layer (thickness: t) has a t/D of 5% or less.

The reason why carbon steel is used as the material for the outermost layer of the tube and the lid member is that it can be easily dissolved in an acid later and is inexpensive. From the viewpoint of ease of acid dissolution, copper or a copper alloy may be considered, but this is difficult due to the need for hermetic welding when assembling the clad material. That is, it is not easy to weld copper or copper alloys together, and even if they are sealed by brazing, they will be heated to around 800°C in the subsequent process, so the brazing parts will start to melt and the seal will break. Therefore, carbon steel will be used for the outermost layer.

(5) Hot extrusion step F After heating the cladding material 7 to a predetermined temperature, the cladding material 7 is
Stretching is performed using an extrusion device 40 as shown in the figure. 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. 7 is a schematic diagram showing the extrusion state by the extrusion device 40 used in the present invention. The extrusion device 40 is a container 41. Punch 42. It is composed of dice 43.

After the clad material 7 is heated to a predetermined temperature, it is coated with lubricating oil and placed in a container 41, pressurized by a punch 42, extruded to a target outer diameter by a die 43, and subjected to a stretching process. Then, when passing through the die 43, diffusion bonding between the metals is performed, and the composite material 8 is obtained. Although the hot extrusion method has been described here, it goes without saying that the same effect can be obtained by using the hot isostatic extrusion method.

(6) Cold outer diameter drawing process G In the above-mentioned hot extrusion process F, it is difficult to extrude the outer diameter to 10 mm or less due to the equipment capacity, so the outer diameter is reduced by cold working. There is.

FIG. 8 is a schematic diagram showing a cold outer diameter drawing process using a die 50, in which a composite material 8 obtained by hot extrusion is
A composite strand 9 is obtained by cold drawing using 0. Since wire drawing using this die 50 is an axially symmetric processing method, it is possible to suppress variations in the thickness of each layer during processing, and the noble metal layer of the composite material 8 is protected by a carbon steel layer. This prevents precious metals from being damaged during cold working.

In this cold outer diameter drawing step G, a groove rolling method or a roller die wire drawing method may be used, but 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.

(7) Outermost layer carbon steel removal step H The outermost carbon steel layer of the composite wire 9 obtained in the previous step is dissolved and removed with acid to expose the noble metal layer and obtain a noble metal clad titanium wire. . This is because as the outer diameter becomes thinner, it becomes more difficult to remove the material by machining, and since the precious metal layer is very thin, if the carbon steel layer is removed by machining, there is a risk that the precious metal layer will also be removed. be.

(8) Finishing die wire drawing process ■ After removing the carbon steel layer obtained in the previous process, the surface of the noble metal clad wire, which is the composite wire 9, lacks smoothness, so it is necessary to smooth the surface and add precious metal luster. Finishing die wire drawing is performed in order to release the wire. In this die wire drawing, a large number of dies are used to reduce the outer diameter one after another, but if the die wire drawing is performed with an area reduction rate of more than 50%, small cracks will occur on the surface of the precious metal, resulting in a good precious metal taland. I can't get titanium wire.

Therefore, the area reduction rate should be 50% or less, and each time the wire is drawn,
By performing softening annealing at a temperature of 0° C. to 700° C. and reducing the outer diameter by repeating die wire drawing, it was possible to obtain a good noble metal clad titanium wire without cracking the noble metal layer.

(Test Example) Clad materials were produced with and without Ni clad Ti bars, and noble metal clad wire rods were produced by hot extrusion and die wire drawing. The following two types of cladding materials for samples were manufactured.

(Sample ■) Low carbon steel pipe Outer diameter: 67mm±0.1 Inner diameter:
60mm1/2 Gold alloy tube Outer diameter: 59mm+0.3 Wall thickness: 0.6mm (12, 50XAu-40χCu-6χNi-4XZ
n) Ni clad Ti bar diameter: 5B, 5 holes ±0.
1 (Ni thickness: 3 mm, Ni: pure Ni, Ti
: Pure Ti (JIS 2nd class)) (Sample ■) Low carbon steel tube Outer diameter: 67mm±0.1 Inner diameter: 60111m:%' 2 Gold alloy tube Outer diameter: 59mm±0.3 Wall thickness: 0.6mm (12 , 50χΔu-40χCu-6χNi-4χZ
n) Pure Ni (Ni-200) tube Outer diameter: 58.5mm
±0.1 Inner diameter: 52mtr: g・2 Pure Ti (JI type 32) rod Diameter: 52mm±0. ] According to the dimensions above, the length is 185 mm (2-3) x 1
Both ends were welded using an electron beam in a vacuum chamber at approximately 0-' Torr to produce a cladding material as shown in FIG.

By the way, the Ni-clad Ti bar of sample (2) was manufactured using the above-mentioned inclined rolling mill in the following manner.

By machining, the outer diameter is 75mm±0.1. An Nl tube with a wall thickness of 5 mm and a length of 700 mm and a diameter of 64 mm±0.1. Fabricate a Ti rod with a length of 690 mm and assemble the cladding material as shown in Figure 2 (at this time, the inside of the N1 pipe is (2-3)
Degas to a vacuum level of 10-'Torr), 800
After heating to a temperature of 100.degree. C., it was stretched and rolled to a diameter of 60.5 mm. The inclined rolling conditions at this time were as follows.

Roll crossing angle (γ): 3°, roll inclination angle (β): 11
゜Roll diameter: 180n+m, Roll rotation speed: 3Q
rpm Next, Sample I II was heated to 800°C and then extruded into a composite material with a diameter of 22 mm by hot extrusion.

The joint strength of this composite material was evaluated. 1 which is a precious metal
Since the layer thickness of No. 2 was very thin, a shear test was conducted at the joint between Ni and Ti to determine the shear strength, which was defined as the joint strength. Figure 9 shows the sample shape, jig shape, and their dimensions used in the shear test method.

Figure 9 is an explanatory diagram showing examples of cross-sectional shapes and dimensions of the sample and jig used in the shear test. Figure 9 (a) is a longitudinal cross-sectional view of the sample, and Figure 9 (b) is a diagram of the jig. Longitudinal sectional view, and also Figure 9 (
C) shows the test mode. Sample 60 is made by cutting the composite material 8 with a diameter of h + w, removing the carbon steel pipe, brass pipe, and Ni layer within the range of length W, and cutting the Ti rod thinner to finish it into a cylinder with a diameter of d2. Ta. On the other hand, in the jig 70, 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 dff (D2 > d3 > dl).
It is composed as follows.

A sample is inserted into the large diameter end of the jig 70 as shown in Figure 9 (C), a load is applied to the upper end of the sample, and the shear strength (kgf/mm2) is determined according to the formula below. Ta.

The bonding strength is 31 kgf/mm2 for sample ①. In the case of sample (2), it was 14 kgf/mm2, indicating that sample (2) is a composite material with superior bonding strength.

The obtained composite material with a diameter of 22 mm was
The diameter was reduced by die wire drawing in the range of % to 20%. At this time, the softening annealing (denoted as X) was performed at 570°C for 20 minutes to 5 minutes. Then, at the timing of softening annealing, the outermost layer of carbon steel was removed using hydrochloric acid, and then the wire was drawn to a diameter of 2.8 mm. This dimensional schedule is as follows.

In the comparative example, the Ni layer was broken at a size of 13 mm in diameter, and the composite wire was divided, making it impossible to draw the wire. On the other hand, when the example of the present invention is used, good processing can be performed, and the diameter is 2.
An 8 mm 12K/Ni/Ti composite wire could be obtained. This diameter of 2.8 mm is flat rolled to have a wall thickness of 1.0 m.
After processing the material to 500 mm, no peeling occurred at each joint interface even when a torsion test (3 twists, 73 twists, and 5 repetitions) was performed.
No defects were found in the observation of the bonding interface using an electron microscope.

Further, this gold-tallad cheek wire with a diameter of 2.8 mm was processed into a frame member for glasses, and then the frame for glasses 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 bonding interface when assembling the eyeglass frames, and a good eyeglass frame could be assembled.

As a result of an experiment using a Ni-clad Ti material used in the examples of the present invention manufactured by hot extrusion, the diameter was 22+n.
The bonding strength at m was 20 kgf/mm2, which was lower than that by hot tilt rolling.

Using this, a composite wire with a diameter of 2.8 mm was manufactured, processed to a thickness of 1.0 mm, and then subjected to a torsion test.
There were no particular problems in the twisting test, but some defects occurred in the twisting test five times. It was confirmed that there were no particular problems when assembling eyeglass frames.

〔effect〕

As described above, in the present invention, multiple clad materials are assembled by fitting using N1 clad Ti core material, vacuum sealed, hot extruded to diffusion bond, diameter reduced by cold working, and acid melted. Since the steel layer is removed at
The present invention has excellent effects, such as simplifying material assembly, obtaining a clad wire with excellent bondability and surface shape, and greatly increasing manufacturing speed.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the manufacturing process of the present invention, Figure 2 is a schematic diagram of a double clad material, Figures 3, 4, and 5 are schematic diagrams of an inclined rolling mill, and Figure 6 is a schematic diagram of a double clad material. A schematic diagram of the clad material, Figure 7 is a schematic diagram of the extrusion process, Figure 8 is a schematic diagram of the die wire drawing process, and Figures 9 (a), (b), and (c) are samples used in the shear test method. and a schematic diagram of a jig. 1...T+ bar material 2...Ni pipe 3...Two-layer clad material 4...Ni-clad Ti bar material 5...Precious metal pipe 6...Carbon steel pipe 7...Multi-layer clad material
8... Composite material 20... Inclined rolling mill 40...
Extrusion device 50... Dice patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono D1 Enoki mixture outer diameter d1 Core outer diameter d2: (ch -1,0) t Omebayashi inner thickness h: 1.5t Idan, Shi2≦h; Giant 5 2h However (5≦w; 10 D2: (D++T, 0) D3≧D2-10.0) d:+: (o++4.Q)

Claims (1)

[Scope of Claims] 1. A method for producing a noble metal clad titanium wire in which a core material made of Ti or a Ti-based alloy is coated with an outer layer material made of a noble metal, wherein the peripheral surface of the core material is coated with Ni or a Ni-based alloy. A step in which the two-layer clad material is made into a two-layer clad material by diffusion bonding through hot processing, and the two-layer clad material is inserted into a pipe made of precious metal, and after further insertion into a steel pipe, the inside of the steel pipe is degassed, and both ends are a step of sealing the four-layer clad material to produce a four-layer clad material; a step of stretching the four-layer clad material by hot extrusion or hot isostatic extrusion to obtain a four-layer clad material; A precious metal clad titanium wire rod characterized by comprising the steps of reducing the diameter by cold working, removing the outermost layer of steel by acid dissolution, and finishing wire drawing by die wire drawing. Production method. Including the step of diffusion bonding Ni or Ni-based alloy to the circumferential surface of the core material by hot inclined rolling using an inclined rolling mill having 2, 3 or 4 cone-shaped rolls to form a two-layer cladding material. A method for manufacturing a noble metal clad titanium wire according to claim 1.