Effect of Prior Austenite Grain Size on Yielding Behavior of the Low-C Martensitic Stainless Steel

Abstract

The effect of the prior austenite grain size on the yielding behavior of as-quenched low-C martensitic stainless steel was investigated. Martensite (Fe-16%Cr-7%Ni-1.2%Mo-1.8%Cu-0.01%C alloy) samples with different prior austenite grain sizes were prepared by heat treatment for various times at 1273K. The microstructures of the martensite were observed by optical microscopy, scanning electron microscopy, electron backscatter diffraction, and X-ray diffractometry. Tensile tests were undertaken at various test speeds. Also, a relaxation test was performed before the tensile tests to determine the behavior of mobile dislocations. A lower elastic limit was observed at lower test speeds and a larger prior austenite grain size. Moreover, a lower tensile strength was observed at a larger prior austenite grain size.