Q235碳素钢多道次热变形中的组织演变及性能

利用热模拟压缩变形实验研究了Q235碳素钢多道次热变形及后续处理过程的组织演变规律.结果表明,采用高温奥氏体的形变再结晶及过冷奥氏体的形变强化相变,可以使Q235低碳钢的铁素体晶粒细化至4-5μm,材料的屈服强度达到400MPa级,延伸率达到40%.经适当的后续处理后,渗碳体、珠光体等第二组织弥散分布于细晶铁素体晶界上,使Q235低碳钢在保持细晶钢原有强度级别和塑性的基础上,屈强比有效降低.

Microstructure Evolution and Properties of Q235 Plain Carbon Steel in Multi-pass Hot Deformation

The microstructure evolution of Q235 plain carbon steel in multi-pass hot deformation was investigated by means of hot compression simulation. The results indieate that fine ferrite grains of 4-5 μm can be achieved by deformation enhanced phase transformation of undercooled austenite in combination with austenitic recrystallization. The yield strength exceeded 400 MPa and the plastic elongation was over 40%. By proper heat treatment after deformation the scattered minor microstructures of cementite and pearlite were distributed on the grain boundaries of fine ferrite grains. The yield ratio was effectively decreased without loss of yield strength and the ductility.