SCM435钢奥氏体连续冷却转变行为

Continuous Cooling Transformation Behavior of Subcooling Austenite of SCM435 Steels

利用热模拟试验机对SCM435钢的奥氏体连续冷却转变(CCT)曲线进行了测定和分析.结果表明:SCM435钢对冷速极为敏感,在冷却速度为0.05℃/s时,可以得到铁素体、珠光体及少量贝氏体组织;当冷速增加到1℃/s时,铁素体转变结束,同时开始产生少量马氏体组织.在实际生产中,通过与模拟预测相结合来控制冷却,抑制块状先析铁素体的生成,同时避免马氏体的大量产生,生产出冷镦性能及球化效果较为理想的基体组织.

The continuous cooling transformation （CCT） curves of SCM435 steels were determined and analyzed using a thermal simulation testing machine. The results showed that SCM435 steels were very sensitive to the cooling rates. Ferrite, pearlite and small amount of bainite were observed when the cooling rate was 0. 05 ℃/s. When the cooling rate increased to 1 ℃/s, ferrite began to end its phase transformation, and a little amount of martensite began to appear. In the actual production, the cooling rates were controlled by combining with the modeling predict so that the production of massive ferrite primary-precipitated was suppressed, the appearance of a large amoun of martensite was avoided and the desirable microstructure for good cold heading property and the spheroidization effect was obtained.