Effect of Finish Rolling Temperature on Direct Quenched Low Alloy Martensite Properties

Abstract

The mechanical properties of direct quenched low alloy martensite steel can be altered considerably through control of the austenite condition prior to quenching. This can be done by varying the finish rolling temperature during hot rolling. The two main aspects to be taken into account are the prior austenite grain size and the accumulated strain due to rolling in the non-recrystallization regime. It is shown that rolling in the non-recrystallization regime increases the strength, but reduces the impact toughness. Increasing the accumulated strain, however, results in increasing the impact toughness for the same strength. Strain accumulation increases the forces during hot rolling and as such imposes a practical limit to the maximum strain that can be accumulated in the austenite. The current work illustrates the optimized combination between strength, impact toughness and processability of a direct quenched low alloy martensitic steel.