Thermoplasticity of high silicon austenitic stainless steel
High temperature tensile and compression experiments on high silicon austenitic stainless steel with different solidification modes and microstructure characteristics were adopted using the Gleeble-3500 thermal simulation machine.The JMatPro software,OM(optical microscope),SEM/EDS(scanning electron microscope/energy dispersive spectrometer)and EPMA(electron probe),were used to studied the thermoplastic variation of high silicon austenitic stainless steel.The results show that the as-cast 6.0 wt.％Si samples solidified in FA mode(with ferrite as the first precipitated phase)have the worst thermo-plasticity,due to the existence of precipitated phase and Weistier-like structure.After homogenization at 1150℃×12h,the solo austenitic structure of 6.0 wt.％Si samples was formed with the section shrinkage reached 76％and elongation 13％.The tensile fracture shows the ductile fracture characteristics and the thermo-plasticity were significantly improved.After the 6.0 wt.％Si sample was homogenized at 1 200 ℃ × 12 h,a large amount of high temperature δ ferrite precipitates again,and the thermo-plasticity decreases significantly as well the fracture took on the characteristics of inter-granular fracture.Combined with hot compression experiments,DRX(dynamic recrystallization)is favored when a moderate amount of elliptical high-temperature δ ferrite is present in the 6.0 wt.％Si specimen.
high silicon austenitic stainless steelδ ferritehomogenization treatmentthermoplasticitysecondary precipitation
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万方数据
维普
