低温变形低碳钢超细铁素体的形成

FORMATION OF ULTRA-FINE FERRITE GRAINS IN LOW CARBON STEELS THROUGH LOW TEMPERATURE HELY DEFORMATION

在Ｇｌｅｅｂｌｅ ２０００热模拟实验机上通过变形同时水淬和减少变形量的方法，对普通低碳钢低温变形获得超细晶铁素体的机制进行了研究．结果表明：超细晶铁素体的获得主要是形变诱导铁素体和铁素体动态再结晶两种机制共同作用的结果在８７Ｏ－７６０℃低温８０％变形可以获得的等轴均匀超细品铁素体．形变量控制铁素体的析出量和动态再结晶．应变速率影响形变诱导铁素体所需的临界变形量．冷却过程对铁素体的析出量不产生决定性影响，但可以控制晶粒长大速度。

Formation mechanism of ultra-fine grains in 'common carbon steel by heavy deformation at low temperature was investigated. The experiments were carried out on a hot deformation simulator (Gleeble 2000) with the methods of water cooling during deformation and decreasing strain. The results show that the formation of ultra-fine grains is resulting from the common effect of dynamic recrystallization and deformation induced ferrite (DIF). When heavy deformation was carried out in 870-760℃, homogeneous and dynamic equiaxed ultra-fine ferrite grains can be obtained. Ferrite content and dynamic recrystallization are controlled by deformation amount. Strain rate influences the critical deformation amount for obtained DIF. Cooling process has not key effect on the ferrite content, yet it can control the grain growth rate.