Mechanical Properties of 32Mn-7Cr-0.6Mo-0.3N Austenitic Steel for Cryogenic Applications

摘要

The tensile, impact, and fracture toughness tests from ambient temperature to 77 K were carried out on 32Mn-7Cr-0.6Mo-0.3N austenitic steel. The fracture surfaces and the phases constitution were analyzed using scanning electron microscopy and x-ray diffraction. The results show that the relation between yielk strength and temperature is #sigma#_(0.2) centre not 300 + 1392.4 exp (-0.0106T). The 77 K yield strength is 883MPa centre not m~(1/2) and the K_(J0.05) value is about 236 MPa centre not m~(1/2). The cryogenic intergranular fracture is fully suppressed. The 77 K fracture surfaces exhibit a tough character composed of many dimples and few small quasi-cleavage facets. The results of x-ray analysis show that the austenite phase of the steel is stable even under cryogenic deformation conditions.