Effect of telmperature 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^−l. 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.

MST/3263