Mechanical properties of 32Mn-7Cr-0.6Mo-0.3N austenitic steel for cryogenic applications

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 fract ure surfaces and the phase constitution were analyzed using scanning electr on microscopy and x-ray diffraction. The results show that the relation bet ween yield strength and temperature is sigma (0.2) (.) 300 + 1392.4 exp (-0 .0106T). The 77 K yield strength is 883 MPa (.) m(1/2) and the K-J0.05 valu e is about 236 MPa (.) m(1/2). The cryogenic intergranular fracture is full y 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 cr yogenic deformation conditions.