提高60Si2CrVAT高强度弹簧钢塑性的工艺实践

Process Practice of Improving Plasticity of 60Si2CrVAT High Strength Spring Steel

某厂生产的60Si2CrVAT钢棒材拉伸塑性差,合格率不超过35%。利用扫描电镜、金相显微镜和显微硬度仪对其拉伸断口、显微组织、硬度进行了分析,得出中心偏析是导致拉伸塑性差的主要原因。通过优化钢水过热度、拉速、比水量以及末端电磁搅拌位置等参数,使60Si2CrVAT弹簧钢的中心偏析比由原来的1.24降低到1.09,力学性能合格率提高到98.5%。

The 60 Si2 CrVAT steel bar produced by a factory has poor tensile plasticity,and the qualified rate is not more than 35%. The tensile fracture, microstructure and hardness were analyzed by means of scanning electron microscope,metallographic microscope and micro-hardness meter. It is concluded that the central segregation is the main reason for the poor tensile plasticity. By optimizing the parameters such as superheat degree of molten steel, drawing speed, specific water quantity and electromagnetic stirring position at the end, the central segregation ratio of 60 Si2 CrVAT spring steel is reduced from 1.24 to 1.09, and the qualified rate of mechanical properties is increased to 98.5%.