高强钢同板性能均匀性差原因分析及改进措施

Cause Analysis on Poor Uniformity of the Properties in Same Plate of High-strength Steel Plate and Improvement Measures

针对TMCP高强钢板同板组织性能均匀性差的问题，以Q550D钢板为例，分析认为主要原因是氧化铁皮、钢板浪形及Mulpic系统设置等导致的钢板冷却均匀性差。通过改造高压水除鳞系统，优化压下分配制度，改造Mulpic冷却工艺参数，改造水冷设备等，提高了钢板表面光洁度，改善了平直度，提高了钢板冷却的均匀性。改进后，同一钢板头、中、尾屈服强度差由44～139 MPa降为20～41 MPa，抗拉强度差由53～186 MPa降为18～26 MPa。

Pointing to poor uniformity problem in the microstructure and properties for same TMCP high strength plate, taking Q550D plate as an example, analysis considered that the main cause for poor cooling uniformity of plate is caused by oxide scale, wave plate shape and setting of Mulpic system, etc. Through transforming the high pressure water descaling system, optimizing draught distribution system, transforming Mulip cooling process parameters and reforming water cooling equipment, etc, the surface fineness and flatness of plate were improved , and the cooling uniformity of steel plate was risen. After improvement, the yield strength difference of head, medium and tail in same plate was decreased from 55-139 MPa to 20-41 MPa and tensile strength difference was decreased from 53-186 MPa to 18-26 MPa.