03Cr18NiMoN节镍双相不锈钢的热变形行为及热加工图

关键词：双相不锈钢； 流变曲线； 本构方程； 热加工图

03Cr18NiMoN low nickel duplex stainless steel

Kunming 650093, Yunnan, China)Abstract：In order to investigate high temperature rolling deformation mechanism and microstructure evolution of 03Cr18NiMoN low nickel duplex stainless steel (DSS), the hot compression tests were conducted using the Gleeble 3800 thermal mechanical simulator at temperature range of 850－1150℃, strain rate of 001－10s-1 and reduction ratio of 50%. Obvious dynamic recrystallization (DRX) was exhibited in the flow curves under high deformation temperature of 950－1150℃ and low strain rate of 001－01s-1. In the early deformation stage, the work hardening rate of tested steel increases with the decrease in deformation temperature and the increase in strain rate, which is dentrimental to dynamic recrystallization softening. The microstructure analysis showed that with the deformation temperature incresing to 1050℃ and the strain rate decreasing, DRX became more complete, which promoted the grain refinement of austenite, while the deformation at higher temperature of 1150℃ made the recrystallized austenite grains coarsen. Under the deformation conditions of 950℃ and 001－1s-1, the effect of ferrite DRV was gradually strengthened. The apparent activation energy of hot deformation Q was calculated as 5497kJ/mol, higher than that of 2205 DSS (451kJ/mol), and the apparent stress exponent was calculated as 6079, indicating that the deformation mechanism is mainly controlled by the low temperature dislocation climbing caused by bulk diffusion. As the hot processing maps shows, the instable region gradually increases with the increase in strain. Combined stress strain curves and microstructure, the optimum processing conditions are at deformation temperature of 950－1050℃ and strain rate of 001－0018s-1 with high power dissipation coefficient (036－050). In addition, the constitutive equation of peak flow stress for tested steel based on Z parameter was established.