Centrifugal casting of large dia. metal tube blanks - using pressurised inert gas in mould, and controlled mould speed to obtain high quality blanks

摘要

Mould is rotated on a horizontal axis, and pressurised inert gas is fed into the mould to create a gas pressure(GP). The mould has a gravitation factor(GF) at which the free surface of the tube blank is formed, the GF being the ratio of centrifugal force:gravity; and the molten metal is poured into the mould. During the pouring of the molten metal into the mould, the latter pref. has a GF which is ca. 300% greater than the GF at which the free surface of the tube blank is formed; and 2-4% metal powder, w.r.t. the wt. of molten metal, is pref. fed into the mould together with the molten metal. Used esp. for the mfr. of blanks for mfg. pipes over 5m. long and 0.6-2.0m. dia. in various alloys, for use in carrying pressurised liqs. at high temp. in mfg. energy, paper and chemicals, and also for carrying natural gas, high quality being required in all cases.