奥氏体再结晶区变形温度对微合金钢晶粒细化的影响

Effects of Deformation Temperature in Austenite Recrystallization Region on Grain Refinement of Microalloyed Steels

采用热模拟实验研究了奥氏体再结晶区变形温度对微合金钢晶粒细化和宏观硬度的影响。结果表明:奥氏体再结晶区变形温度显著影响钢材的显微组织。变形温度由1100℃降至1000℃,原奥氏体晶粒尺寸由60.0μm大幅度细化至34.1μm,细化了43.2%。最终获得了铁素体+珠光体组织,铁素体晶粒尺寸也实现了显著的细化,由15.5μm细化至8.8μm,细化程度达43.2%。但奥氏体再结晶区变形温度对宏观硬度的影响不大。因此,为了提高钢材,尤其是厚板的强韧性,再结晶区变形温度应适当降低。

The effects of deformation temperature in austenitic recrystallization region on grain refining and macro-hardness in microalloyed steels were studied by thermal simulation experiment. The results show that the deformation temperature in austenite recrystallization region has a significant influence on the microstructure of the steel. When the deformation temperature decreases from 1100 ℃ to 1000 ℃ step by step, the original austenite grain size is refined from 60.0 μm to 34.μm, and the grain size is refined by 43.2%. Finally ferrite ＋ pearlite microstructure is obtained, ferrite grain size also achieves a significant refinement from 15.5pLm to 8.8 μm, the degree of refinement is 43.2%. But the deformation temperature in austenite recrystallization region has little effect on the macro-hardness. Therefore, in order to improve the strength and toughness of the steel, especially the thick plate, the deformation temperature should be reduced appropriately.