JPS6356003B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is used in corrosive environments and applications that require electrical conductivity, such as insoluble electrodes for surface treatment of steel plates, tin plating, precious metal plating, etc. This invention relates to a method for manufacturing titanium-clad copper rectangular materials used for equipment electrodes and current-carrying bodies.

(Prior art) Current-carrying bodies used in corrosive environments are required to have corrosion resistance and conductivity.
It is called titanium material. ), and the core is made of pure copper or copper alloy (hereinafter referred to as copper material) with excellent conductivity.
A titanium-copper composite material with a rectangular cross section is used, which is formed by integrally joining the two.

As a method for joining such composite materials, there is a method in which a titanium material and a copper material are overlapped and resistance welded to join them together.

However, since one of the materials to be welded is a copper material with good conductivity, resistance welding is difficult between flat plates of copper and titanium. In order to perform resistance welding, it is necessary to weld through a copper strip or copper net at the joint interface. In this case, the copper material and titanium material are only partially joined at the strip or net portion, which may cause quality problems or problems. There is a production problem.

Another method for joining copper and titanium materials is explosive bonding, but this method tends to produce weak intermetallic compounds locally at the joint interface, which can cause cracking during finishing. There is a problem that peeling easily occurs.

As described above, the conventional bonding methods had various problems, so the present inventors worked on the development of a bonding means that is one step ahead of these methods. In other words, we developed an extrusion technology for titanium-clad copper round bars using hot isostatic extrusion, which can diffusion bond the interface of composite materials under high temperature and high pressure and keep the area ratio of the composite material uniform in the extrusion direction. We proceeded with this and achieved some results.

Therefore, we wondered if this extrusion technology could be applied to the extrusion of rectangular materials, and when we conducted various experiments, we found that the outer skin frequently seizes, which became a problem. That is, since titanium is prone to seizing, if a die is used that has a profile with uneven surface pressure, it is extremely likely to seize. In this regard, die design and lubricant development are urgently needed, but they have not yet been completed. Further, the outer skin of the extruded titanium material has a wall thickness distribution, and the wall thickness in the thickness direction tends to be thin and the thickness in the width direction tends to become thick, which poses a quality problem.

As a means for preventing the seizure, it is conceivable to cover the extruded billet with a protective material made of copper or a copper alloy that serves as an anti-seizure material and then extrude the rectangular material. However, after extrusion, the protective layer of copper or copper alloy that forms the outermost layer of the extruded material must be dissolved by pickling, etc., or removed by grinding, cutting, etc., and this removal is prohibited due to pollution regulations. There are problems in terms of productivity and productivity, such as high costs.

(Problems to be Solved by the Invention) Therefore, the present inventors have proposed a method that is practically effective, in which a sound round bar composite extruded material obtained by hot isostatic extrusion is made into a rectangular material by cold rolling. However, as a result of various experiments, we found that when a hot isostatically extruded round bar is flattened by cold rolling, interfacial delamination may occur even if the joint interface of the round bar is sound. There is an urgent need to establish manufacturing conditions.

The present invention has been made in view of the above, and it is possible to flatten a sound titanium clad copper without cracking or peeling when flattening a round bar composite extruded material obtained by hot isostatic extrusion. The purpose of this study is to clarify the manufacturing conditions of square timber.

(Means for Solving the Problems) A characteristic feature of the present invention for achieving the above object is that an outer shell cylinder made of a titanium material is attached to the outer peripheral surface of a core member made of a copper material. The composite billet is hot isostatically extruded to obtain a bar-shaped composite extruded material in which the outer skin made of the Ti material is diffusion bonded to the core made of the copper material, and then cold rolled or cold rolled. After rolling, softening annealing and re-rolling,
When processing the composite extruded material into a rectangular shape, the composite billet is heated to 600 to 750°C and the extrusion ratio is 6.
Hot isostatic extrusion is carried out using the above-mentioned high area reduction processing, the reduction ratio in cold rolling and re-rolling is 60% or less, and softening annealing is carried out in a temperature range of 550 to 650°C.

(Example) Hereinafter, a method for manufacturing a titanium-clad copper rectangular material of the present invention will be described in detail.

First, as shown in FIGS. 1 and 2, the composite billet 1, in which the outer skin cylinder 3 made of titanium material is attached to the outer peripheral surface of the core member 2 made of copper material, is attached to the third
As shown in the figure, it is charged into a container 31 and hot isostatically extruded.

The composite billet 1 includes a rear cover member 5 attached to one end of the outer skin tube 3, which is a titanium tube, by TIG welding or the like.
After the core member 2 is fitted into this, the tip cover member 4 is welded to the other end of the outer skin cylinder 3.

The inside of the composite billet 1 is normally degassed and sealed, but the exhaust pipe 6 for this purpose is the first
As shown in the figure, it is provided in a penetrating manner in the front cover member 4, and is sealed after degassing. Further, as shown in FIG. 2, an exhaust hole 7 communicating with the inside of the billet may be provided in the front cover member 4 without performing degassing sealing.

The front and rear lid members 4 and 5 are made of titanium, copper, or a copper alloy material, but when both are made of titanium, the entire surface of the core 12 of the composite extruded material 11 is covered with the outer skin 13 of titanium. An encapsulated composite extrudate 11 is obtained.

The composite billet 1 is heated to 600-750°C during hot isostatic extrusion. Below 600℃,
If the interfacial bonding of the extruded material becomes insufficient and such an extruded material is cold rolled, interfacial delamination is likely to occur between the core and the outer skin of the composite extruded material. On the other hand, 750
If the temperature exceeds .degree. C., intermetallic compounds between titanium and copper are likely to form at the interface of the extruded material, and cracks are likely to occur at the interface during subsequent cold rolling.

The heated composite billet 1 is loaded into a container 31 of a hot isostatic extruder with the front cover member 4 facing the die 34 as shown in FIG. It is extruded through a die 34 having a round hole. At this time, the extrusion ratio is set to 6 or more. If it is less than 6, the interfacial bonding will be insufficient even if the temperature of the composite billet is increased, and interfacial peeling will occur during cold rolling of the composite extruded material. The reason for this is that when the extrusion ratio is small (less than 6), even if hot isostatic extrusion is carried out under high temperature and high pressure conditions favorable for joining dissimilar materials, the generation of surface activity, that is, new surfaces, is slight. It is presumed that.

A composite extruded material 11 obtained by hot isostatic extrusion under specific extrusion conditions has a core 12 and an outer skin 1.
The interface with No. 3 is sound, no brittle intermetallic compounds are formed, and they are integrated by diffusion bonding. Further, in the extruded composite material 11, the area ratio between the core 12 and the outer skin 13 is maintained in the extrusion direction. The core part 12 and the outer skin 13 are formed by extruding the core member 2 and the outer skin cylinder 3 of the composite billet 1.

Next, this sound composite extruded material 11 is cold rolled to obtain a rectangular material with a desired thickness.
To obtain the desired thickness, after cold rolling,
It is softened and annealed, then re-rolled and processed into a rectangular material of the desired thickness.

At this time, the reduction ratio of cold rolling and re-rolling is 60%.
Do the following. According to the inventor's rolling tests, peeling echoes were detected in ultrasonic examinations when the rolling reduction was 63% or more, but no abnormality was observed when the rolling reduction was 60% or less. In actual operation, it is preferable to roll at a reduction rate of 50% or less for safety reasons.

Softening annealing after cold rolling is performed at a temperature range of 550 to 650°C. If the temperature is less than 550℃, the titanium material will not soften much, but if it exceeds 650℃, intermetallic compounds will be generated at the bonding interface where titanium and copper are diffusion bonded, and cracks and peeling will occur at the interface during the re-rolling process. do.

Incidentally, as a current-carrying body used in a corrosive environment, there are cases where a plate-shaped object is required, not just a rectangular material. can be easily obtained.

That is, as shown in FIG. 4, an outer skin 2 made of a titanium material is placed on the outer peripheral surface of a core part 22 made of a copper material.
3 is diffusion bonded titanium clad copper rectangular material 2
By bringing two or more (three in Figure 4) pieces of 1 into contact in the width direction and welding and connecting the abutting portions using titanium wire as filler material by TIG welding, etc., a plate material with a desired width can be obtained. can get. In addition, when it is necessary to connect the core parts of the connected rectangular members, that is, the copper materials, the titanium outer skin portions at both ends of the rectangular members in the width direction may be removed and welded together. In addition, if the lengthwise ends of the rectangular material are made of titanium, it is possible to remove the titanium from these ends and weld the cores in contact with each other in the lengthwise direction. It is possible to obtain a rectangular piece of approximately 300 mm in size, and also to fill in copper at the end where the titanium material has been removed.

Next, specific examples and reference examples are listed.

Example 1 A pure titanium plate with a thickness of 7 mm was bent into a cylindrical shape and the mating surfaces were welded to form an outer cylinder with an outer diameter of 144φ,
A 128φ pure copper rod was inserted into the inside of the tube, and both ends of the outer shell tube were covered with titanium lid members to create a composite billet.

The composite billet was heated to 750°C and hot isostatically extruded to obtain a composite extruded material with an outer diameter of 38φ, which was cold rolled to a thickness of 20 mm, resulting in a width of 41.5 mm.
A rectangular piece of wood was obtained. As a result of ultrasonic flaw detection of this rectangular material, there were no abnormalities and it was found to be sound.

In addition, in this example, the following relational expression between the thickness and width of the rectangular material by rolling was found.

W=3D-T/2.15 However, W: Width of rectangular material after rolling T: Thickness of rectangular material after rolling D: Diameter of composite extruded material before rolling The rectangular material is continuously cold-rolled to a thickness of 14 mm. When it was rolled and subjected to ultrasonic flaw detection, peeling echoes were detected.

Therefore, the 20 mm thick rectangular material was softened and annealed at 630°C for 15 minutes, then cold rolled to a thickness of 14 mm and subjected to ultrasonic testing, but no peeling echoes were observed and a sound rectangular material was obtained. Ta.

Example 2 A composite billet similar to Example 1 was created, and 750
It was heated to ℃ and hot isostatically extruded to obtain a composite extruded material with an outer diameter of 50φ. This extruded material is cold rolled,
When the thickness is 25mm, softening annealing is performed at 600°C for 30 minutes.
It was rolled again to a thickness of 20 mm to obtain a rectangular material with a width of 61.5 mm and a thickness of 20 mm. When this rectangular material was subjected to ultrasonic flaw detection, it was found to be sound.

The side surfaces of the rectangular material were cut and removed, and titanium was welded to obtain a titanium-clad copper plate with a width of 120 mm and a thickness of 20 mm.

Reference example: A titanium plate with a thickness of 6 mm is bent and the mating surfaces are welded to form an outer cylinder with an outer diameter of 128φ.
Double structure material with 114φ pure copper rod inserted inside, outer diameter 143φ
A composite billet was prepared by fitting a protective cylinder with a rear cover member made of copper alloy having an inner diameter of 129φ and welding a front cover member having an exhaust hole of 5φ in the center to the open end of the protective cylinder.

The composite billet was heated to 700° C. and hot isostatically extruded to obtain a rectangular composite extruded material with a width of 80 mm and a thickness of 15 mm. The protective layer of the extruded material (corresponding to the extruded part of the protective cylinder) was dissolved and removed with nitric acid to obtain a rectangular titanium clad copper material, which was then cold rolled to a width
It was formed into a size of 79 mm x 6 mm thick. Rolled rectangular material 5
The sheets were successively welded in the width direction using titanium wire filler metal to obtain a wide titanium clad copper plate measuring 390 mm wide x 6 mm thick x 1000 mm long.

(Effects of the Invention) As explained above, according to the present invention, a composite billet in which an outer skin tube made of a titanium material is attached to the outer peripheral surface of a core member made of a copper material is heated to 600 to 750°C. Since hot isostatic extrusion is carried out at an extrusion ratio of 6 or more, the area ratio is constant in the extrusion direction, and a sound composite extruded material is obtained without the formation of fragile intermetallic compounds at the interface between the outer skin and the core. . and,
This composite extruded material is cold-rolled at a reduction rate of 60% or less, or after the above-mentioned cold rolling, at a temperature of 550 to 650℃.
Since the material is softened and annealed at the same temperature and then re-rolled at the above-mentioned reduction rate, the required thickness is achieved with a nearly constant thickness distribution of titanium and a good cross-sectional shape without causing any cracks at the interface between the outer skin and the core. It is possible to obtain rectangular pieces of wood. Furthermore, titanium clad copper plates of arbitrary width and length can be easily obtained by welding and connecting such rectangular members. Furthermore, the means of the present invention comprises:
It can be easily carried out by a combination process of hot isostatic extrusion, cold rolling, and annealing, and has excellent industrial productivity and great practical value.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of two examples of composite billets used in the present invention, Figure 3 is a cross-sectional explanatory view showing the hot isostatic extrusion state of the composite billet, and Figure 4 is a rectangular piece of titanium clad copper. FIG. 2 is a cross-sectional view showing the structure of a plate material formed using the method. DESCRIPTION OF SYMBOLS 1... Composite billet, 2... Core member, 3... Outer cylinder, 11... Composite extrusion material, 12... Core part, 1
3...Outer skin.

Claims (1)

[Claims] 1 Hot isostatically extruding a composite billet in which an outer skin tube made of titanium material is attached to the outer circumferential corner of a core member made of copper material, and forming the titanium material on the core member made of copper material. After obtaining a rod-shaped composite extruded material with a diffusion bonded outer skin, it is cold rolled, or after cold rolling, it is softened and annealed and re-rolled, and when the composite extruded material is processed into a rectangular shape, the composite billet is heated to 600-750°C, hot isostatically extruded with high surface reduction processing at an extrusion ratio of 6 or more, cold rolled and re-rolled with a reduction ratio of 60% or less, and subjected to softening annealing.
A method for manufacturing a titanium clad copper rectangular material, characterized in that the manufacturing method is carried out in a temperature range of 550 to 650°C.