Hot deformation behaviour of and processing map for an Ni-based austenitic stainless steel

Abstract The hot deformation behaviour of an Ni-based austenitic stainless steel (Fe-31Ni-15Cr austenitic steel) was investigated by isothermal tensile testing at temperatures ranging from 900–1100 °C and at strain rates of 0.01, 0.1, 1 and 10 s−1. The effects of the deformation parameters were studied through analyses of true stress–strain curves. Processing maps were built based on the dynamic material model. The fracture morphology was observed. The stress of the alloy has a dependence on strain rate and deformation temperature. A modified Johnson–Cook constitutive model was built and examined. The entire tensile fracture surface presenting typical plastic fracture morphology is covered by dimples and voids. The processing maps reveal that instability mainly appears in Ni-based austenitic stainless steel at low deformation temperatures ranging from 900–940 °C.