中碳马氏体钢温轧和退火过程中的组织演变

Microstructure Evolution of Medium Carbon Martensite Steel During Warm Rolling and Annealing

利用SEM和EBSD研究了轧制温度和退火时间对中碳马氏体钢组织演变的影响。结果表明400℃轧制后,马氏体板条的基体出现了漩涡状,随轧制温度的升高漩涡状消失,同时铁素体由条带状趋于等轴状,碳化物分布越来越均匀。不同温度轧后经600℃退火1 h,铁素体平均晶粒尺寸为0.60~0.71μm,达到亚微米级别;随轧制温度的升高,小角度晶界所占的比例呈现由小到大再到小的变化趋势,500℃轧后600℃退火1 h,小角度晶界所占比例达到最大,为21.9%。

Effects of rolling temperature and annealing time on microstructure evolution of medium carbon martensite steel were investigated by SEM and EBSD. The results show that, vortices appear on the matrix of lath martensite after rolling at 400℃, and then disappear with the increase of rolling temperature. Meanwhile, banded ferrites tend to be equiaxed, and carbide distribution becomes more and more uniform. After rolling at different temperatures and then annealing at 600 ℃ for 1 h, the average ferrite grain size is 0.60-0.71 μm, which reaches sub-micron level. The changing trend of the proportion of low-angle grain boundaries is from low to high and then to low with the increase of rolling temperature. And the proportion of low-angle grain boundaries reaches the maximum of 21.9% after rolling at 500℃ and then annealing at 600℃ for 1 h.