退火温度对20MnSi钢ECAP变形组织的影响

采用C方式等径弯曲通道变形（ECAP）法制备了平均晶粒尺寸-0.20 μm的亚微晶20MnSi钢,研究了退火温度对ECAP变形组织的影响.结果表明,随退火温度升高,ECAP变形获得的亚微晶铁素体变形组织在原位逐渐演变为再结晶组织,300～500℃退火1 h后,亚微晶铁素体组织稳定,晶粒无明显长大.退火温度高于500℃后,铁素体晶粒开始明显长大,650℃退火后的铁素体平均晶粒尺寸-8μm.经ECAP变形的珠光体组织在较低温度退火时,渗碳体具有较强的球化能力.

Effect of annealing temperature on microstructure of 20MnSi steel processed by equal channel angular pressing

20MnSi steel with a submicrometer ferrite grain size of about 0.20μm was manufactured by four passes of equal channel angular pressing via route C at room temperature, and the effect of annealing temperature on the ECAP deformation microstructure was examined. The results show that with the annealing temperature increased, the ECAP deformed microstructure is evolved into recrystallized grains insitu. At annealing temperatures of 300-500℃ for 1 h, the submicrometer ferrite microstructure is relatively stable with negligible grain growth. At annealing temperatures above 500℃, the ferrite grain starts to grow significantly, and there is an average grain size of about 8μm after annealing at 650℃ for 1 h. The cementite in the pearlite by ECAP has a stronger ability of spheroidization at a lower annealing temperature.