低碳微合金钢贝氏体相变及组织细化的研究

Bainite Transformation and Structure Refinement of Low Carbon Microalloy Steel

针对低碳铌、钛微合金钢,采用Gleeble-1500热模拟机进行了加热、变形及冷却试验,对不同工艺制度下的显微组织进行了分析。结果表明,加热时间较长时,不利于随后冷却奥氏体向等轴铁素体相变,而发生贝氏体相变;在奥氏体区进行不同应变量的变形,随着奥氏体的形变量加大,相变贝氏体的组织细化;变形后适当增加弛豫时间,相变的贝氏体组织细化。

Experiments of heating, deformation and cooling were carried out on low carbon Ti-Nb microalloy steel by use of Gleeble-1500 thermomechanical simulator, and the microstructure was analyzed under the different process conditions. The results show that when the heating time is long, it is unfavorable for austenite to transform into equiaxed ferrite, but rather to bainite during the subsequent cooling. The transformed bainite structure is refined with increasing the strain of austenite. If appropriately increase the relaxation time after deformation, the transformed bainitic structure can be refined.