Q370qE-HPS钢轧制加热温度优化研究

Investigation and optimization on billet reheating temperature for hot rolling of Q370qE-HPS steel

针对新一代低碳铌微合金化Q370qE-HPS高性能桥梁钢的生产,为了兼顾钢坯加热时Nb的溶解与原始奥氏体晶粒的细化以实现成品钢板良好的综合性能,借助热力学计算、模拟加热、组织观察等方法,研究了加热温度对Nb的溶解-析出行为与含Nb第二相粒子的影响,以及对原始奥氏体晶粒的影响,并据此来优化加热温度制度。结果表明,随着加热温度的升高,Q370qE-HPS钢中Nb的固溶量增加、原始奥氏体晶粒长大;加热温度为1200℃时,Nb的溶解量超过80%、原始奥晶粒尺寸小于100μm,是理想的加热温度。

Aiming at the production of a new generation of low carbon niobium microalloying Q370QE-HPS high performance bridge steel,in order to take into account the dissolution of Nb and the prior austenite grain(PAG)refinement during billet reheating to obtain good comprehensive property of final plate,the means of thermodynamic calculation,simulated heating,microstructure observation and other methods were used to study the effects of billet reheating temperature(BRT)on the solution-precipitation behavior of Nb,the Nb-contained second phase particles and the PAG,and hence,the BRT was optimized accordingly.The results show that the solid solution of Nb increased and the PAG grew with the increasing BRT.At the BRT of 1200℃,the solid solution ratio of Nb exceeded 80%and the average size of PAG was less than 100μm,which is the ideal reheating temperature.