卷取温度对热轧高延伸凸缘型钢组织性能的影响

Effect of Coiling Temperature on Microstructure and Properties of Hot-rolled High Extension Flange Section Steel

基于双相钢的传统热轧技术制备了高延伸凸缘型钢,并揭示了卷取温度对组织、力学性能、凸缘性能及析出强化的影响规律。结果表明,随卷取温度的升高,组织中板条状贝氏体逐渐演化成球状的贝氏体,且均匀弥散地分布在铁素体的周边。由于超快冷和卷取温度升高,铁素体内析出相也逐渐增多。热轧板的可移动位错效应使得屈服强度从541 MPa增加到655 MPa,组织的变化和析出物效应使抗拉强度从830 MPa降低到788 MPa,断后伸长率也从17.2%提升到了25.6%。随着卷曲温度的升高,热轧板的扩孔机制从直线的穿晶断裂变成了蜿蜒曲折的韧性断裂,扩孔性能最终从52%显著提高到83%。

The high extension flange steel was prepared based on traditional hot rolling technology of double-phase steel,and the effects of coiling temperature on the microstructure,mechanical properties,flange properties and precipitation strengthening were revealed.The results show that with the increase of coiling temperature,the lath-shaped bainite in structure gradually evolves into spherical bainite,and the bainite is distributed uniformly around the ferrite.The precipitation in ferrite is increased gradually due to the ultra-fast cooling and the increase of coiling temperature.The movable dislocation effect of the hot rolled plate increases the yield strength from 541 MPa to 655 MPa,the microstructure change and the precipitate effect reduces the tensile strength from 830 MPa to 788 MPa,and the elongation after fracture increases from 17.2%to 25.6%.With the increase of coiling temperature,the expanding hole mechanism of hot-rolled plate changes from the linear transgranular fracture to the sinuous ductile fracture,and the expanding hole performance finally improves significantly from 52%to 83%.