JPH01224130A - Method and device for manufacturing high melting point metal pipe - Google Patents

Abstract

PURPOSE:To improve the strength of a high m.p. metal pipe by inserting a circular columnar plug into the hole of a high m.p. metal body and rotary forging the outer face of the metal body of the plug position with rotating the plug. CONSTITUTION:The roll hammer 5 arranging plural hammer members on the circumference is provided and die 3 and shoe 4 are arranged at the inner side thereof. The circular columnar plug connected by a connection rod 7 is inserted to the inner part of the hole of a high m.p. metal body 2 manufactured by press forming, etc., and rotary forging is performed from the outer face via the shoe 4 and die 3 by the roll hammer 5 on the metal body 2 of the specified temp. with rotating the plug 1. The working is performed by moving the plug 1 inside the pipe 2 as well as repeating the rotary forging. Due to the rotary forging being executed by a interposing the pipe 2 from the inner and outer sides, the breakdown of the pipe 2 and the fixture of the plug 1 are prevented and an uniform pipe 2 is formed. Consequently the strength is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a high melting point metal pipe and an apparatus for manufacturing the same.

(Prior art) Conventionally, pipes made of high-melting point metals such as tungsten and molybdenum are made by forming high-melting point metal bodies made by powder metallurgy or melting into round rods by rolling, rolling, forging, etc. It was manufactured by punching holes or welding it into a plate shape.

As for manufacturing equipment, only boat-based swaging machines were used in the process of forming round bars and plates.

[Problem that the invention seeks to solve]

In the method of drilling a round bar as described above, it was not possible to manufacture a thin and homogeneous pipe. Furthermore, the method of welding the plates has a problem in that the strength of the welded portion is weak.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a method for manufacturing a thin, homogeneous, high-strength, high-melting-point metal pipe, and an apparatus for manufacturing the same.

[Means and effects for solving the problems] The present invention produces a cylindrical high-melting point metal body and swags the high-melting point metal body to obtain a thin-walled, homogeneous high-melting point metal pipe with high strength. More specifically, a cylindrical plug (hanging core) having a diameter smaller than the inner diameter of the high melting point metal body is inserted into the hole of the cylindrical high melting point metal body, and the plug is rotated. By rolling the outer surface of the high melting point metal body at the position of the plug while rolling, a high melting point metal pipe can be easily obtained. The cylindrical high melting point metal body can be manufactured by a conventional powder metallurgy method or melting method in which high melting point metal powder is press-formed and sintered. If the density of the high melting point metal body is extremely low, problems such as cracks will occur in the next rolling process, so it is desirable that the density of the high melting point metal body is 85% or more of the theoretical density. Furthermore, when rolling a cylindrical high-melting point metal body, it is possible to process it without inserting a cylindrical plug inside, but unevenness will occur on the inner surface during processing, and the wall thickness will be significantly reduced. There were disadvantages such as the fact that the processing efficiency was not improved. The present inventor has completed the present invention as a result of various studies on rolling processing methods for the high melting point metal body, in which the plug is inserted into the hole of the high melting point metal body, It has been discovered that it is possible to manufacture a high-melting point metal pipe suitable for the purpose only when the pipe is rolled instead of rotated. If the plug is not rotated, the plug and pipe will stick together due to the rolling process, making it impossible to remove the plug.

In the high melting point metal pipe manufacturing device, the main parts of the device are connected to a die 3 and a shoe 4 housed in a case 6 by a roll hammer 5 and a connecting rod 7 in which several hammer parts are arranged on the circumference. It consists of a cylindrical plug 1. The case is rotated together with the shoe, die and cylindrical plug by a driving machine. The shoe and the die are held so as to freely move in the circumferential uniaxial direction within the case, and when the shoe hits a roll hammer, the high melting point metal pipe 2 on the outside of the cylindrical plug held at the center position is rolled. . The refractory metal pipe to be processed is held manually or mechanically and moved back and forth to process the entire length.

Examples of manufacturing high melting point metal pipes according to the present invention will be described below.

〔Example〕

Molded by normal rubber press method and heated to 1700 in hydrogen.
C. to obtain a molybdenum cylindrical sintered body having an outer diameter of 14 mm and an inner diameter of 9 mm. The density of the sintered body is 9.8 (96% of theoretical density)
), using a swaging machine with a cylindrical plug (hanging core) made of cemented carbide as shown in Figure 1, the processing temperature was approximately 800°C, and the outer diameter was 11 x the inner diameter. 8
Even the cabinet was tumbled. The rotation speed of the die and the cylindrical plug was 500 revolutions per minute. Also, swaging 1
The reduction in outer diameter per rotation is 0.15 to 0.2 wm,
The rolling process was performed repeatedly while changing the die.

The molybdenum pipe did not break during processing, and the cylindrical plug and pipe did not stick together.

The density of the obtained molybdenum pipe was 10.06, which was 98.6% of the theoretical density. In addition, the hardness is 209~2
It was 1411v. The inner surface of the pipe had a smooth finish.

As described above, by using the method and apparatus for manufacturing a high-melting point metal pipe of the present invention, a thin, homogeneous, high-strength high-melting point metal pipe could be manufactured.

[Effects of the Invention] As described above, by using the method for manufacturing a high melting point metal pipe of the present invention, a thin, homogeneous, and high strength high melting point metal pipe can be manufactured. Furthermore, if a cylindrical high melting point metal body that is a material before swaging is used that has a theoretical density of 85% or more, cranks and the like will not occur during the rolling process and the manufacturing yield will be improved.

Further, by using the swaging machine of the present invention, a thin-walled, homogeneous, high-strength, high-melting-point metal pipe can be manufactured. The swaging machine of the present invention can be used not only for manufacturing high melting point metal pipes but also for manufacturing various other metal pipes.

When cemented carbide is used as the material for the cylindrical plug used in the swaging machine of the present invention, it is difficult to deform and has high strength, so the inner surface of the pipe can be finished smoothly.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a schematic structure of an example of the refractory metal pipe manufacturing apparatus of the present invention, and FIG. 2 is a front view of the same. In the figure, l2 cylindrical plug, 2: high melting point metal pipe 3: die,
4: Shoe 5: Roll hammer, 6: Case 7: Connecting rod. Patent applicant Nippon Tungsten Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. A cylindrical plug having a diameter smaller than the inner diameter of the high melting point metal body is inserted into the hole of a cylindrical high melting point metal body, and the plug is rotated to the position of the plug. A method for producing a high melting point metal pipe, which comprises rolling the outer surface of a certain high melting point metal body. 2. The method for manufacturing a high melting point metal pipe according to claim 1, wherein the density of the cylindrical high melting point metal body is 85% or more of the theoretical density. 3. In a swaging machine that rotates opposing dies around a rotating shaft and rolls a workpiece by striking it with a hammer, a cylindrical plug that rotates in accordance with the rotation of the dies is placed at the center position between the dies. A swaging machine characterized by comprising: 4. The swaging machine according to claim 3, wherein the plug is made of cemented carbide.