JPH0246939A - Manufacture of conjugated wire material - Google Patents

Abstract

PURPOSE:To improve the junction property and the quality of a product by forming a conjugated stock by pressure-reducing and closing up hermetically an outer layer material of a cylindrical shape and a core material, and subsequently, rolling it under a specified reducing area ratio condition by a cone roller type inclination rolling mill, and repeating wire drawing. CONSTITUTION:An outer layer material 12 of a cylindrical shape and a core material 11 having a circular cross section are degreased and washed, and fitted, and a disk 12a is arranged on both ends and they are closed up hermetically by electron beam welding in a pressure-reduced chamber. An obtained conjugated stock 10 is heated at the temperature of 800-1,300 deg.C, and hot rolling is executed by using an inclination rolling mill having three pieces or more of cone type rollers. In this case, at the time of a first rolling, the reducing area ratio is controlled to <=75%, and at a second and subsequent times, rolling is executed by raising the percentage reducing area ratio >=80%, and a clad material 13 is obtained. Subsequently, a product is obtained by executing wire drawing cold working through a die. Since the spread junction degree of the core material 11 and the outer layer material 12 is high, the junction property of the product and the quality such as corrosion resistance, airtightness are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a composite wire for sealing used as a terminal lead wire for electronic equipment components such as transistors and capacitors.

(Prior art) In general, terminal lead wires for electronic equipment components suffer from heat deterioration.
The requirements are that no processing deterioration occurs, that the coefficient of thermal expansion is close to that of sealing glass, that the glass sealing properties are good, that the glass has excellent airtightness and corrosion resistance, and that the price is low.

Conventionally, the material for this type of terminal lead wire is NiCo-
In order to ensure corrosion resistance on the surface of Fe alloy wire, so-called copper alloy wire, surface treatment such as Au or Ni solder plating is applied, and the wire is used without being subjected to heat treatment such as annealing.

(Problem to be solved by the invention) By the way, when applying Ni plating to a core material such as a Kovar alloy, it is difficult to make the plating thickness uniform, and since the bonding strength with the core material is not sufficient, the plating layer may be damaged by bending, etc. There were problems such as cranking, peeling of the plating layer, and oxidation and rusting.

As a countermeasure to this problem, the applicant has already developed a method of fitting the outer layer material to the core material and hot rolling it using an inclined rolling mill with three or more cone-shaped rolls to increase the joint strength of the inner and outer layers. An application has been filed (Patent Application No. 6l-181635)
.

However, in the case of this method, it is effective when the deformation resistance of the outer layer material is larger than that of the core material, but in the opposite case, that is, in a structure where Kovar etc. is used for the core material and Ni is used for the outer layer material. In this case, the deformation resistance of the core material is greater than that of the outer layer material, so there is a problem in that it is difficult to obtain sufficient bonding strength.

The inventor conducted experiments and research to obtain sufficient joint strength even when the deformation resistance of the core material is greater than that of the outer layer material. It has been found that sufficient joint strength can be obtained by appropriately determining the temperature of the rolled material and the area reduction rate.

The present invention was made based on this knowledge, and its purpose is to increase the bonding strength between the core material and the outer layer material,
To provide a method for producing a composite wire for sealing, which does not cause peeling of the outer layer material or cracking, and has excellent corrosion resistance, airtightness, etc.

[Means for solving problems]

The method for manufacturing a composite wire according to the present invention is to assemble the composite material by reducing the pressure between the cylindrical outer layer material and the core material, sealing both ends of the outer layer material or the boundary between the outer layer material and the core material. After heating this to 800°C to 1300°C, the first rolling is carried out using an inclined rolling mill having three or more cone-shaped rolls so that the area reduction is 75% or less and the total area reduction is 80% or more. After rolling to achieve the desired diameter, heat treatment and wire drawing are repeated to obtain a crand wire rod with the target small diameter.

[Function] According to the present invention, the bonding strength between the core material and the outer layer material is increased, and airtightness and corrosion resistance are improved.

〔Example〕

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

FIG. 1 is a front view of a composite material used in the present invention, and FIG. 2 is a local sectional view thereof, and numeral 10 in the figure indicates the composite material. After the composite material 10 is heated in a heating furnace (not shown),
The material is fed to an inclined rolling mill capable of high-pressure rolling as shown in Figure 5, where it is hot-rolled to form a cladding material 13.
After pretreatment such as scale removal, heat treatment and wire drawing as shown in FIG. 6 are repeated to produce a thin diameter clad wire 14, which is a composite wire +4.

The main steps will be explained step by step below.

[Preparation of composite material] The surface of the rod-shaped core material 11 melted with a circular cross section and the inner peripheral surface of the cylindrical outer layer material 12 having an inner diameter equal to the diameter of the core material 11 are degreased, cleaned, and diffused. The oil 1 contamination that obstructs this is removed, and then these are fitted together and sealed by electron beam welding at both ends using a disc 12a made of the same material as the outer layer material 12 in a reduced pressure chamber.

The inside of the outer layer material 12 is sealed in the next heating step. If the coefficient of thermal expansion of the outer layer material 12 is larger than that of the core material 11, a gap is created between the core material 11 and the outer layer material 12 during the heating process. This is due to the fact that air enters the bond and forms oxides at the interface, resulting in insufficient diffusion bonding force.

In addition to the above-mentioned method, a method of reducing the pressure between the core material 11 and the outer layer material 12 is to fit the core material 11 and the outer layer material 12 together and weld the metal boundaries at both ends. After sealing, a method may be adopted in which a hole is opened in a part and the pressure is degassed and depressurized through the hole using a vacuum pump.

Further, the outer layer material 12 is fitted to the core material 11, and the outer layer material 12 is cold-drawn so that its inner peripheral surface is in contact with the surface of the core material 11 without changing the diameter of the core material 11. A method may be used in which the boundaries between the core material 11 and the outer layer material 12 at both ends are welded and sealed.

However, in this cold drawing process, if the outer layer material 12 is drawn more than the gap between the outer layer material 12 and the core material 11, a gap will occur between the outer layer material 12 and the core material 11 due to processing distortion. It is necessary to keep the amount of reduction within the range of the gap between the outer layer material 12 and the core material 11.

The composite material 10 created in this manner is heated and then hot rolled to promote diffusion bonding at the interface between the core material 11 and the outer layer material 12.

The heating temperature for this composite material 10 is the N of the outer layer material 12.
The upper limit was set at 1300°C to suppress oxidative deterioration of the i surface, and the lower limit was set at 80°C to promote diffusion bonding at the interface.
0”C.

[Hot rolling process] Hot rolling is performed using an inclined rolling mill as shown in FIGS. 3 to 5. The reason for using an inclined rolling mill is that compared to the groove rolling method or the forging method, greater bonding strength can be obtained between the core material 11 and the outer layer material 12, and there is less variation in the thickness of the outer layer material 12 (
, due to improved roundness.

Hot rolling with an inclined rolling mill may be performed two or more times as necessary, but the area reduction rate during the first hot rolling is 1
In order to prevent 2 from protruding between the rolling rolls and forming a gap with the core material 11, it is set to 75% or less. Note that from the second time onward, the diffusion bonding between the core material 11 and the outer layer material 12 has progressed, so there is no risk of the core material 11 and the outer layer material 12 peeling off even if high pressure rolling with an area reduction rate of about 90X is performed. . When the composite material 10 is finished into the clad material 13, the total area reduction rate is set to be 80% or more in order to obtain sufficient bonding strength.

FIG. 3 is a schematic diagram showing the inclined rolling mill 4 used in the present invention (
In the figure, the rolls 1 and 2 are shown as a sectional view taken along the line ■-■ in FIG. 4), FIG. 4 is a front view taken along the rV-rV line in FIG. 3, and FIG. be. The inclined rolling mill 4 has three cone-shaped rolls 1 facing around the pass line.
2.3, the three rolls 1, 2.3 have gorge parts 1a, 2a, 3a at the exit end of the composite material 10, and the composite material 10 is separated from the gorge parts 1a, 2a, 3a. The diameter of the inlet side is gradually reduced toward the shaft end, and the outlet side is enlarged to have truncated conical inlet faces 1b, 2b, 3b and outlet faces 1c, 2c, 3c, respectively, and the outlet face 1c.
, 2c, 3c are the distances from the pass line to the gorge part 1a.
, 2a, 3a and the pass line.

Each of these cone-shaped rolls 1, 2.3 has its entrance surfaces 1b, 2b, 3b located upstream in the direction of movement of the composite material 10, and has an axis Y-Y and a gorge section. The intersection point O (hereinafter referred to as the roll setting center) with the plane including 1a, 2a, and 3a is set as the pass line χ-X on the same plane orthogonal to the lotus line X-X of the composite material 10.
They are arranged at approximately equal intervals around the circumference. The axial center line YLY of each roll 1, 2.3 is set at the roll setting center opening, and the front axis end is at the pass line X as shown in Fig. 3 in relation to the pass line −
The front shaft ends are crossed (inclined) by an intersection angle T so as to approach toward x, and as shown in FIGS. It is tilted only. The rolls 1, 2.3 are connected to a drive source (not shown) and are driven to rotate in the same direction as shown by arrows in FIG. 4, and the hot composite material IO caught between these rolls is It is moved in the longitudinal direction of the shaft while being rotationally driven around the axial center line, that is, it is caused to move in a spiral manner.

While the composite material 10 is spirally moved between rolls,
As shown in FIG. 3, the outer diameter is reduced at the roll bite part A, and the composite material 10 is subjected to high pressure with a maximum area reduction of 80 to 90%, so that the rolled surface B of the composite material 10 is formed into a truncated conical shape. Thereafter, the cladding material 13 is formed into a round rod shape having a predetermined outer diameter at the gorge portions 1a, 2a, 3a and the outlet surfaces 1et2c, 3c.

The reason why an inclined rolling mill with three or more cone-shaped rolls is used is to avoid internal cracking caused by so-called Mannesmann fracture, which occurs in the center of the rolled material in an inclined rolling mill with two rolls. It's for a reason.

(Wire drawing process) After removing scale from the surface, this clad material 13 undergoes heat treatment,
A composite wire rod with a predetermined diameter is produced by applying a lubricant and repeatedly drawing the wire with a die.The wire drawing method used for this process is die wire drawing.

Performs cold working such as roller die wire drawing and groove rolling.

Preferably, die wire drawing is employed to suppress variations in the thickness of the outer layer material 12 in the cladding material 13.

In the case of cold working, work hardening of the material occurs, so it is usually 7
11□70 in an atmosphere each time 0 to 80X surface reduction processing is performed.
Heat treatment is performed at 0 to 950°C.

As mentioned above, the core material 11 is made of Kovar alloy, and the outer layer material 1 is made of Kovar alloy.
When Ni is used for No. 2, brittle intermetallic compounds are not generated at the bonding interface, so the heat treatment temperature may be the same as the heat treatment temperature for Kovar alloy.

[Test Example 1] Core material such as Kovar alloy having the composition shown in Table 1 and N
After melting the outer layer material made by i, casting, and forging, the core material has an outer diameter of 60 mm.
After cutting and finishing the outer layer material into a cylindrical shape with an inner diameter of 60 mm, an outer diameter of 70 mm, and a length of 310 mm, the core material was fitted to the outer layer material.
A composite material 10 was manufactured by electron beam welding Ni lids to both ends of the outer layer material in a vacuum chamber of 3 to 4 x 10' Torr to seal the ends.

(Margin below) Next, this composite material IO was heated to 1100″C, and then hot worked using the following three methods to create a clad material 13 with a diameter of 20 mm, which was then pickled and After scale removal treatment, cold wire drawing processing and heat treatment are repeated using a die.
A clad wire 14 having a diameter of 0.5 mm was manufactured.

Note that hot working methods include inclined rolling method, which is the method of the present invention;
As a comparative example, three methods are used: a groove roll rolling method and a forging method.

The rolling conditions using the inclined rolling mill are as follows.

Intersection angle: 3" Inclination angle: 13° Pass schedule 1st pass near 0φll1m → 45φmm (area reduction rate 58.
7χ) Nip pass = 45φmm → 20φmm (area reduction rate 80, 2χ) The rolling conditions for the groove rolling method are to use an oval/round groove roll series, and hot-roll a material with a diameter of 70mm to a diameter of 20mm in 12 passes. Area reduction rate per pass: approx. 20χ
), and the forging method was performed by forging from two directions.

Furthermore, as another comparative example, a clad wire obtained by applying Ni plating to a thickness of 13 μm on a Kovar alloy wire having an outer diameter of 0.51 in a Watt bath and a current density of 1.0 Ndn+2 was used as a comparative material.

The corrosion resistance, airtightness, and glass sealing properties of each of the clad wire rods obtained as described above were tested as test materials.

The Ni thickness distribution in the cross section of the outer layer material was measured. The results are shown in Table 2.

In addition, the corrosion resistance test was performed by repeatedly applying bending stress to the test piece from horizontal to 45°C 10 times, and then applying this test piece to Nac.
The salt water spray test was carried out under the following conditions: l concentration 5χ, p[(6 to 7.5), liquid temperature 350°C, and treatment time 48 hours.

The airtightness test was conducted by heating at 750''C for 3 minutes in the air, then sealing the hard glass at 1000''C in a nitrogen atmosphere, and then applying slow cracking using 11e gas. The glass sealing property was evaluated by pulling out the test material sealed under the above conditions using a tensile tester and measuring its pulling strength.

As is clear from Table 2, the clad wire obtained by the method of the present invention has excellent corrosion resistance, airtightness, and glass sealing property, and also has Ni
It was also confirmed that there was very little variation in the thickness of the plating layer.

[Test Example 2] A composite material obtained by combining the Kovar alloy core material and the Ni outer layer material described above was heated and hot-rolled using the slope rolling method according to the pass schedule shown in Table 3.

Table 3 Corrosion resistance and airtightness similar to those in Test Example 1.

As a result of testing the Ni plating layer thickness, good results were obtained for both pass schedules A and B, but when pass schedule C was used, the Ni plating layer overhanged between the rolling rolls. It was in a state where rolling was not possible.

This fact shows that good results can be obtained by suppressing the area reduction rate in the first rolling to 75% or less.

[Test Example 3] Next, a Kovar alloy core material having the composition shown in Table 1 and Ni
The outer layer material is melted, cast, and forged.

By rolling, the core material has a diameter of 58 mm and 55 mm, and a length of 1
00mm round bar shape, and the outer layer material has an inner diameter of 60mm.
After cutting and finishing into a cylindrical shape with an outer diameter of 70 mm and a length of 1000 mm, one end of this outer layer material was drawn, a core material was inserted from the other end, and the outer layer material was drawn to have a diameter of 65 mm. After drawing, the mouth drawn portion was cut and removed, and the boundary between the outer layer material and the core material at both ends was sealed by TIG welding to obtain a composite material.

Each of these composite materials is heated to a diameter of 0.5 by hot rolling using an inclined rolling method and wire drawing using a die.
A clad wire of wa was manufactured. As a result, when the diameter of the core material before drawing was 58 mm, the outer layer material and the core material were separated from each other, and it was not possible to diffusion bond them.

On the other hand, good diffusion bonding was obtained when the diameter of the core material before drawing was 55 mm.

This fact shows that when assembling cladding materials by drawing, it is desirable to limit the drawing to a degree that does not reduce the outer diameter of the core material.

〔Effect of the invention] As described above, in the method of the present invention, Ni-C is used as the core material.

We decided to manufacture the clad wire by using Fe alloy and Ni for the outer layer material, hot rolling with reduced pressure between them, and repeating heat treatment and wire drawing. The present invention has excellent effects, such as being able to obtain a composite wire material that has a high degree of diffusion bonding with the material and has excellent corrosion resistance and airtightness.

[Brief explanation of the drawing]

Fig. 1 is a front view of the composite material, Fig. 2 is a local sectional view, Fig. 3 is a sectional view taken along the line ■-■ in Fig. 4 of the inclined rolling mill used in the method of the present invention, and Fig. 4 is a Figure IV-I
The front view of the inclined rolling mill seen from the V-line direction, Figure 5 is the same (
The side view and FIG. 6 are explanatory views of the cold wire drawing process. 1.2.3... Roll rolls la, 2a, 3a...
Gorge part 4... Inclined rolling mill 1b, 2b, 3b-...
Inlet surface 1c, 2c, 3c...Exit surface 10...
・Composite material 11... Core material 12... Outer layer material 13.
... Clad material 14 ... Clad m material patent Applicant: Sumitomo Metal Industries, Ltd. (1 other person) Agent: Patent attorney
Funeral map of Noboru Kono

Claims (1)

[Claims] 1. In a method for manufacturing a composite wire in which an outer layer material made of Ni is bonded to the peripheral surface of a core material made of a Ni-Co-Fe alloy, the outer layer material and the core material having a cylindrical shape are A composite material is assembled by sealing both ends of the outer layer material or the boundary between the outer layer material and the core material under reduced pressure between
After heating to ℃, stretch rolling is performed using an inclined rolling mill having three or more cone-shaped rolls so that the initial rolling has an area reduction of 75% or less and a total area reduction of 80% or more. A method for producing a composite wire rod, which is characterized in that the clad wire rod is then repeatedly subjected to heat treatment and wire drawing processing to obtain a clad wire rod with a target small diameter. 2. Fit a Ni cylindrical outer layer material to an alloy core material, draw the outer layer material so that the diameter of the core material does not change, make the inner surface of the outer layer material adhere to the circumferential surface of the core material, and then press both ends. 2. The method for manufacturing a composite wire according to claim 1, further comprising the step of assembling the composite material by sealing the boundary between the outer layer material and the core material.