Inventors:
James W. Colzani - Menomonee Falls WI
Nelson H. Kehl - Hinsdale IL
Assignee:
Midwest Instrument Co., Inc. - Hartland WI
International Classification:
C21C 548
Abstract:
For a molten metal stirring lance a steel tubular member is coated interiorly with wax, for instance, and a refractory material plug is cast in the member. The plug extends from one end of the member and leaves a clear space near the other end. Melting the wax out leaves a thin gas passageway gap around the plug. The end having the clear space is capped and connected to a gas feed pipe which is surrounded by a stiffener member. The latter member is convered with a refractory material protective sheath. The refractory material in the tubular member erodes or ablates by a small amount during each use in molten metal to keep the gas discharge gap clear.