加热速率对22MnB5超高强度钢奥氏体化的影响

摘要

22MnB5 ultra high strength steel was austenitizated at different heating rates using a Gleeble 3500 thermo-mechanical simulator.The effects of heating rates on austenitization temperatures of Ac1 ,Ac3 and on austenitization time were investigated,and the relational expression between heating rate and Ac1 was built up.The results show that both the Ac1 and Ac3 of the steel increased with the increase of heating rates.With the increase of heating rates,the temperature Ac1 increased rapidly with the heating rate below 25 ℃·s-1 and increased slowly then tended to a constant with the heating rates over 25 ℃·s-1 .Meanwhile,the austenitization temperature range values (Ac3-Ac1 )increased and austenitization time interval values decreased with the increase of the heating rates.%在Gleeble 3500型热力模拟试验机上对22MnB5超高强度钢在不同加热速率(10~100℃·s-1)下进行了奥氏体化,研究了加热速率对奥氏体化温度Ac1,Ac3及奥氏体转变时间的影响,并建立了加热速率与Ac1的关系式.结果表明:该钢的Ac1与Ac3都随着加热速率的增大而升高;当加热速率低于25℃·s-1时,Ac1随加热速率的增大快速升高,当高于25℃·s-1时,Ac1缓慢升高并趋向恒定;随着加热速率的提高,奥氏体化温度区间(Ac3~Ac1)大小呈升高趋势,奥氏体转变时间缩短.