The effect of two-step solution heat treatment on the impact properties of Hadfield austenitic manganese steel

Abstract

Hadfield austenitic manganese steel is made of iron with 1.0–1.4 percentage Carbon and 10–14 percentage Manganese. Hadfield steel was processed to solution heat treatment to eliminate the carbide (Fe, Mn)3C. This study aims to make a smaller grain size of Hadfield steel at once with solution heat treatment. It was expected to improve toughness of Hadfield steel. Solution heat treatment was carried out in stages by implementing pre-isothermal heating at a lower temperature with two variations at 600 degree C and 700 degree C before undergoing high austenitization heating. Pre-isothermal heat at above 450 degree C was promoting pearlite growth. Pearlite growth starting from austenite grain boundary then reformed new grain, which has a smaller size than prior austenite. Second, stage of austenitization heating then was performed at 980 degree C to transform new small grain pearlite to austenite. An agitated water quench was used to ensure a faster cooling rate to achieve 100 percentage austenite structure. Results demonstrate that sample that underwent a stepped heat treatment process at 600 degree C followed by austenitization at 980 degree C produced finer (smaller) austenite grains. That sample had the highest impact value of 329.1 J/Cm2 in comparison to other specimens.