摘要
在DIL805热膨胀仪上测定了70Mn钢的临界相变点Ac1、Ac3和Ms。采用膨胀法结合金相-硬度法测定了70Mn钢的连续冷却转变曲线。结合70Mn钢显微组织观察,确定了磨球热处理过程中避免上贝氏体组织出现的冷却速度应大于40℃/s。建立了相变点-冷却速度以及相变量-冷却速度之间的数学方程,并回归计算得到了拟合度较高的相变模型。结果表明,计算值与试验值之间能够很好的吻合,证明了该相变模型的可行性。
The critical phase transformation temperatures Ac1,Ac3and Msof 70Mn steel were determined on a DIL805 thermal dilatometer.Continuous cooling transformation diagram of 70Mn steel was obtained by dilatometric measurement combined with metallographic microstructure observation and microhardness test.The microstructure of the steel at different cooling rates was studied on a Zeiss Imager M2m optical microscope.The optimum cooling rate of 70Mn steel for grinding balls should be faster than 40 ℃ / s to avoid the upper bainite during heat treatment.The model of phase transformation point-cooling rate and phase transformation volume fraction-cooling rate was built by regression calculation based on experiments.The result shows that the calculated value and experimental value match well,which proves the feasibility of the model.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2014年第4期208-212,共5页
Transactions of Materials and Heat Treatment
关键词
70Mn钢
CCT曲线
相变模型
70Mn steel
CCT diagram
phase transformation model
