低碳贝氏体钢AH80DB过冷奥氏体连续冷却转变与等温转变

Continuous cooling transformation and isothermal transformation of supercooled austenite for AH80DB low carbon bainitic steel

利用DIL805A淬火相变膨胀仪测定了AH80DB低碳贝氏体钢的连续冷却转变(CCT)曲线与等温转变(TTT)曲线,并结合金相-显微硬度法确定了过冷奥氏体在不同冷速冷却及不同温度等温时的组织转变。结果表明,连续冷却转变时,在0.2~30℃/s冷速范围内,可得到贝氏体组织;AH80DB钢的等温转变曲线为珠光体区在右,贝氏体区在左的双鼻型,在Ms^600℃等温可获得贝氏体组织。

Continuous cooling transformation curves and isothermal transformation curves of supercooled austenite for AH 80DB low carbon bainitic steel were investigated by DIL 805 A phase transformation dilatometer .Microstructure evolution of the tested steel at different cooling rates and different isothermal temperatures was studied based on metallographic microscopy and microhardness tester .The results show that bainite could be obtained in a wide cooling rate range from 0.2 ℃/s to 30 ℃/s during continuous cooling process .The pearlite and bainite regions are well separated in the isothermal transformation curves .And the pearlite region is on the upper right of the bainite region .Bainite can be obtained by isothermal treatment in the temperature range from Ms to 600 ℃.