38CrMoAl钢的组织转变规律研究

Study on Law of Microstructure Transformation for 38CrMoAl Steel

文章以38CrMoAl钢为研究对象,利用FORMASTOR-F全自动相变仪,测定了试验钢连续冷却转变的CCT曲线。结果表明:当冷却速度为0.2~0.5℃/s时,室温组织为先共析铁素体+珠光体;当冷却速度为0.5~1℃/s时,出现少量贝氏体,室温组织为铁素体+珠光体+贝氏体;当冷却速度为1℃/s时,在贝氏体转变区最上部,靠近Bs的温度处形成贝氏体,室温下组织为上贝氏体;当冷却速度为2~5℃/s时,马氏体不断增加,贝氏体逐渐减少,室温下为贝氏体+马氏体的混合组织;当冷却速度不小于5℃/s,室温下组织全部为马氏体。研究结果为热处理工艺的制定提供了参考依据。

In the paper,the continuous cooling transformation(CCT)curve of test steel is determined with FORMASTOR-F full automatic phase transformation instrument by taking 38CrMoAl steel as the research object.The results showed that the microstructure at room temperature was proeutectoid ferrite+pearlite when cooling rate was 0.2~0.5℃/s;the microstructure at room temperature was ferrite+pearlite+bainite and there was a small amount of bainite when cooling rate was 0.5~1℃/s;the bainite was formed at the temperature near Bs in the uppermost part of transition zone for bainite and the microstructure at room temperature was upper bainite when cooling rate was 1℃/s;the martensite increased continuously and bainite decreased gradually as well as the microstructure at room temperature was mixed microstructure of bainite+martensite when cooling rate was 2~5℃/s;the microstructure at room temperature was just martensite when cooling rate was not less than 5℃/s,which provide the reference basis for formulating heat treatment process.