钒微合金化钢的热塑性探讨  

Discussion about the thermoplasticity of vanadium microalloyed steel

作　　者：沈彬彬 SHEN Bin-bin(Shandong Iron and Steel Group Laiwu Branch Technology Center,Laiwu 271104,China)

机构地区：[1]山东钢铁集团莱芜分公司技术中心

出　　处：《物理测试》2019年第5期9-11,共3页Physics Examination and Testing

摘　　要：利用Gleeble-3800对钒微合金化钢的高温塑性进行了测定,并通过扫描电镜对不同温度下试验钢拉断后的断口形貌进行了观察分析。结果表明:随着温度降低,热塑性降低,断面收缩率降低,奥氏体化温度以上拉伸时,断口以深韧窝为主,部分韧窝底部分布着第二相粒子;但铁素体相变温度以下拉伸时,断口呈现沿晶断裂特征,断裂面上分布着浅而小的韧窝,降低了材料的热塑性;随着温度的升高,断面收缩率不断增加,试验钢在850℃及其以上温度拉伸时的断面收缩率均大于60%,在连铸坯生产时矫直温度不低于850℃能够有效减少铸坯表面裂纹发生率,因此,在连铸坯生产时适宜的矫直温度应该不低于850℃。The high temperature plasticity of vanadium microalloyed steel was measured by Gleeble-3800,and the fracture morphology of the test steel breaking at different temperatures was observed and analyzed by scanning electron microscopy. The results show that with the decrease of temperature,the thermal plasticity decreases,and the section shrinkage decreases. When the tensile temperature is above the austenite temperature,the fracture is mainly deep dimples,and the second phase particles are distributed at the bottom of some dimples. However,when the tensile temperature is lower than the ferrite phase transition temperature,the fracture is characterized by intergranular fracture,and shallow and small dimples are distributed on the fracture surface,which reduces the thermal plasticity of the material.With the increase of temperature,the section shrinkage rate increases continuously,and the section shrinkage rate of the test steel is more than 60% when stretched at 850 ℃ or above. The straightening temperature of the continuous casting billet is not lower than 850 ℃,which can effectively reduce the occurrence of surface cracks in the billet. Therefore,the appropriate straightening temperature should not be lower than 850 ℃.

关 键 词：钒微合金化钢 热塑性 断口形貌 断面收缩率 表面裂纹 

分 类 号：TG1[金属学及工艺—金属学]