600MPa级汽车桥壳钢生产实践

介绍了河北普阳钢铁有限公司生产600 MPa级汽车桥壳钢板600QK的生产工艺及产品性能特点,研究了不同未再结晶区开轧温度和待温厚度对600QK钢板的组织和力学性能的影响。结果表明:铌、钛微合金元素的复合添加,有助于细化铁素体晶粒,提高钢材的强度和韧性。通过控制成品氮含量不大于50×10~(-6),未发现大尺寸TiN夹杂物。采用两阶段控轧工艺,随未再结晶区开轧温度的降低和待温厚度的增加,组织更加细化,钢板的抗拉强度及伸长率变化不大,但屈服强度及-20℃冲击功显著增加。产品各项性能良好且稳定,满足了用户的需求。

Production practice of 600 MPa grade axle housings steel for automobile

The features of process and properties of 600 MPa grade axle housings steel plate for automobile was presented and the effect of different rolling start temperature and workpiece thickness in non- recrystallization region on microstructure and properties was investigated.The results showed that the addition of Nb- Ti microalloving elements contributed to refine the ferrite grain,and improved strength and toughness of the steel.By controlling casting slab nitrogen content less than 50×10-6,not larger size TiN inclusions was found in steel.With decreasing rolling temperature,increasing workpiece thickness of non- recrystallization region in two stage controlled rolling process,the microstructures of plate was refined,and the yield strength and impact toughness of -20 ℃ significantly increased,but no obvious effect on tensile strength and elongation was found.The properties of products were fine and stable,and meet the requirements of customers.