Effect of Ni and Cu Addition on Carbide Precipitation in Hadfield Steel

Study on austenitic high-manganese steels-III

Abstract

Some Hadfield steels added with 3% Ni and 3% Cu were studied mainly by micrography on isothermal carbide precipitation after solution treatment. By addition of 3% Ni, both carbide precipitation and pearlitic constituent precipitation in Hadfield steels were retarded and these precipitation temperature ranges were limited in a narrow range than those of the standard steel.
Growth rate of pearlitic constituents in steels was decreased remarkably by addition of 3% Ni. On the other hand, by addition of 3% Cu, pearlitic constituent precipitation in steels was only slightly retarded, but grain boundary carbide precipitation was accelerated at above about 650°C. Strength of steels after solution treatment was decreased slightly by addition of these elements, but toughness, especially elongation of steels was increased. As the content of carbon in Hadfield steels was lowered, both grain-boundary carbide precipitation and pearlitic-constituent precipitation were gradually decreased.
High-Mn steel containing 0.65%C, cooled slowly after solution treatment, had nearly perfect austenitic structure and the strength of these steels was slightly impaired but the toughness was remarkably increased as compared with that of a standard Hadfield steel.