Study on the technology of bimetal spinning forging hollow tungsten sheet and tube
Hollow tungsten plate used in automobile igniter contact has the advantages of solid tungsten sheet, but also can play a good cooling and heat dissipation, arc burning resistance, to prevent metal transfer caused by poor contact also has a more obvious effect. Therefore, in recent years, the contacts of automobile distributors in Japan, the Soviet Union, West Germany, Britain and the United States and other countries have been changed to consist of a hollow tungsten slice and a solid tungsten slice, whose service life is longer than that of the contacts composed of two solid slices, according to the analysis of foreign contacts. Most of the hollow pieces have machining deformation structure. These hollow pieces are mostly made by cutting tungsten rods and punching holes, and the yield is low. A few are made by pressing and sintering powder. Tungsten tube with thick wall and small diameter (less than 5mm in diameter) can replace the electrical products in high temperature system, prolong the service life, can also be used for titanium evaporation spray plasma nozzle and thermocouple protection sleeve used at 2000-3000 degrees Celsius. However, it is very difficult to make this kind of tungsten tube with small diameter.
Under the existing tungsten rod production conditions, hollow thick tube billet or bimetallic strip billet is prepared by isostatic pressing, and the hollow tungsten sheet with outer weight of 4 -- 5mn and inner hole of 2mm and certain length of tungsten tube are produced by rotary forging machine.
