Thermal deformation behavior and microstructure of nuclear austenitic stainless steel

Gleeble-1500D thermal simulation tester was employed in the hot-compression investigation of as-cast nuclear 304 austenitic stainless steel under conditions: deformation temperature 950–1200°C; deformations 30% and 50%; deformation rates 0.01 and 0.1 s⁻¹. The results show that the flow stress decreases with temperature rise under the same strain rate and deformation, that the flow stress increases with deformation under the same temperature and strain rate, and that the flow stress increases with strain rate under the same temperature condition, i.e., work hardening becomes distinct. Materials exhibit better strength-toughness when the strain rate is 0.01 s⁻¹, the deformation is 50%, and the temperature is 1050°C. Supported by the National Science and Technology Pillar Program in the Eleventh Five-year Plan Period (Grant No. 2007BAF02B07, 50821140308), the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20070109001) and the Natural Science Foundation of Shanxi Province (Grant No. 2008012008-2)