Effect of temperature and strain rate on tensile behaviour of M250 maraging steel

Abstract

The effect of temperature and strain rate on the 0-2% yield strength, ultimate tensile strength, and percentage elongation of M250 maraging steel was investigated under uniaxial tensile conditions in the temperature range from 25 (room temperature) to 550 C and strain rate range 10-4-10-1 s-1. Up to 400 C the steel shows essentially strain rate insensitive behaviour with a gradual decrease in the 0-2% yield strength and ultimate tensile strength. The elongation remains constant at all strain rates up to 300 C. Fractographic analysis indicates that the increasing strain rate induces strain constraint resulting in an increased dimple size. An elongated structure was observed at temperatures above 400 C. X-ray diffraction reveals the presence of reverted austenite in the specimens tested at 550 C. 1996 The Institute of Materials.