In another paper presented at this conference, success in extending die life in pressure die casting high melting metals such as pure copper through the use of heated nickel-base alloy dies is presented (1). This development prepares the way for improving the die casting economics of other relatively high melting materials such as brasses and bronzes. A variety of parts including builders hardware currently die cast in a zinc alloy, plumbing components, and industrial valves and fittings, may well be economically produced in solid brass by pressure die casting. The work reported here combines the new die technology with semi-solid metal (SSM) forming. SSM further enhances die life by minimizing the heat input to the die on each shot. This paper describes the finegrained globular microstructure starting stock required for the process. A cost effective approach to producing the two-phase semi-solid billets by magnetohydrodynamic stirring of the melt, controlled cooling, reheating or direct transfer to the shot sleeve of the die casting machine, is under development.
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