Vacuum casting of alloy steels etc. - where tubes contg. alloys are blown into melt, esp. while casting high purity ingots used to mfr. forgings

摘要

A molten metal is poured into a mould which is located in a vacuum chamber. During the pouring of the metal into the evacuated mould, one or more alloying elements in the form of hollow, closed tubes are fed into the mould. Each tube is pref. driven into the mould at a speed of 10-15 m/s by a stream of pressurised gas, esp. argon at 400-600 kPa driving the tube through a pipe. The tube is pref. filled with powdered alloys. The pref. tube is 250-450 mm long x 120-200 mm dia. x 2-2.5 mm wall thickness, and total wt. 3.5-9.5 kg. The tube is pref. filled with an inert gas, esp. argon, and closed by concave end caps. Various pneumatic pipes are used to drive the tubes into the mould. Optimum alloying conditions are achieved.