Continuous casting of aluminium alloy rod - controlled to avoid solidification shrinkage of pptn. during hot rolling and quenching

摘要

In the continuous casting of a rod of Al alloy contg. 0.5-0.9 wt.% Si, 0.6-0.9 wt.% Mg and balance Al by casting the molten alloy in a wheel-type continuous casting machine, continuously hot rolling the cast bar to rod and continuously quenching the rod, casting and bar removal from the casting wheel groove are carried out at a rate and a temp. such that solidification shrinkage will not occur, and the bar temp. is raised between the casting wheel and the rolling mill to above the temp. at which pptn. of alloying metals at the alloy grain boundaries would occur. Pref. the cast bar is removed from the groove at below 940 (800-940) deg.F and is heated to 850-1140 deg.F before entry into the rolling mill. The method is esp. useful for prodn. of 6201 Al alloy redraw rod. The method avoids the solidification shrinkage and massive ppte. formation problems of the process of US3613767 and permits rolling of the rod at temps. in the upper portion of the solutionising range of 6201 Al alloy. The resulting prod. has improved strength.