GB941828A - Improvements in or relating to a process of prehardening austenitic manganese steel - Google Patents

Abstract

Work-hardenable austenitic manganese steel is prehardened before use by heating it to a temperature above that at which ferrite dissolves in the austenitic matrix and below that at which carbide fully dissolves into the matrix, e.g. at a uniform temperature between 1100 and 1300 DEG F. for 5.5 to 6.5 hours, to precipitate carbide needles within the grains, allowing the steel to cool to ambient temperature, e.g. slowly for 10 to 48 hours, heating it to a higher temperature than that in the first heating step but within the first heating range, e.g. at 1350 to 1500 DEG F. for not less than two hours, to diminish the size and round off the sharp points of the carbide needles, thereby partially reclaiming the original ductility of the steel, and quenching the steel preferably in water. A modified Hadfield steel is referred to of composition:- C 0.65 to 1.4%, Mn 10 to 14%, P max. 0.1%, S 0.01 to 2%, Si 0.1 to 0.3%, Fe balance.