Research on constitutive equation of DIWA353 steel used in hemisphere head of power station nearby recrystallization temperature

To simulate the DIWA353 steel used in boiler nearby recrystallization temperature accurately by using finite element,the high temperature constitutive model of this material must be researched firstly.Thermal simulation experimental machine is used to do the high temperature hot compression experiments for the DIWA353 steel used in boiler under different strain rates and temperatures nearby recrystallization temperature.Multi-bank data of true stress-true strain is gotten,and the hot deformation activation energy of DIWA353 is obtained,and the constitutive equation of steady-state flow stress under the circumstance of high temperature is constructed.The results show that DIWA353 steel is positive strain rate sensitized material when it is at temperature of 850-1050 ℃,and the steady-state flow stress decreases with the increase of deformation temperature,but increases with the increase of strain rate.