卷后冷速对600MPa级钢板微观组织的影响

为了研究卷取后冷却速度对600MPa级低碳贝氏体高强钢钢板组织和力学性能的影响,探究获得其最佳性能的途径和方法,利用光学显微镜和透射电子显微镜（TEM）对样品进行微观组织观察和分析。研究卷取后在空气中冷却速度对卷板的板头、板间、板尾的微观组织影响。结果表明：600 MPa级钢板的组织主要由针状铁素体、板条铁素体、粒状贝氏体、板条贝氏体、M/A组成。卷板头部和尾部在空气中冷却速度较快,针状铁素体较多,强度高;中间部位冷却速度较慢,板条铁素体、粒状贝氏体较多,强度低。

Influences of cooling rate on microstructure of 600 MPa grade steel after coiling

In order to study the impact of cooling rate on microstructure and mechanical properties in the low carbon bainitic steel of 600 MPa grade,and explore the ways and methods of obtaining the best performance,this paper investigated the microstructure of the 600 MPa grade steel is investigated by OM and TEM observations.After the steel is curled,the effect of cooling rate in the air on the microstructures in the coil plate head,the plate and the plate tail are researched. The results show that for 600 MPa grade steel,the microstructure is mainly composed by acicular ferrite,lath ferrite,granular bainite,lath bainite,and M/A. The higher cooling rate in the coil head and tail leads to more acicular ferrite,while more lath ferrite and granular bainite are obtained due to lower cooling rate in the middle section of the coil. Thus the strength of the coil head and tail is higher than that in the middle.