【摘要】 利用膨胀法结合金相-硬度法,在Gleeble-3800热模拟机上测定了27CrMo27S钢的临界点Ac1、Ac3以及Ms;测定了该钢在不同冷却速度下连续冷却时的膨胀曲线,获得了连续冷却转变曲线(CCT曲线);研究了冷却速度对该钢组织及硬度的影响。结果表明在相当低的冷却速度范围内可获得贝氏体组织。当冷却速度小于1℃/s,转变产物为铁素体、珠光体和贝氏体(F+P+B),当冷却速度为1～6℃/s时转变产物是铁素体和贝氏体(F+B),当冷却速度为8～24℃/s时转变产物是贝氏体和马氏体(B+M),当冷却速度大于24℃/s时,转变产物为完全马氏体(M)。该钢种动态CCT曲线的测定可为生产实践和新工艺的制定提供一定的参考依据。更多还原

【Abstract】 By dilatometric change referencing microscopic test and hardness measurement,the critical point at Ac1,Ac3 and Ms of 27CrMo27S steel was determined in Gleeble-3800 thermal mechanical simulator.By measuring the different expanding curves of CCT in different cooling rate,CCT diagram was obtained.The influence of cooling rate on steel microstructure and hardness was studied.The results show that in a very low range of cooling rate,bainite structure is obtained.The products of austenite transformation are ferrite,pearlite and bainite when the cooling rate is lower than 1℃/s;Those will be ferrite and bainite when the cooling rate is in the range of 1 to 6℃/s;those will be bainite and martensite when the cooling rate is in the range of 8 to 24℃/s and those will be totally martensite if the cooling rate is higher than 24℃/s.All those provide the references for productive practice and establishing new processes.更多还原