中板大梁钢700L生产实践

PRODUCTION PRACTICE OF 700L MEDIUM PLATE BEAM PLATE

采用低碳微合金化成分设计、热机械轧制加回火工艺,研发出700 MPa级别高强汽车大梁钢。对轧制态和不同回火温度下的大梁钢板进行了显微组织及力学性能检测,结果表明:钢板经620℃回火后,组织为均匀的铁素体和索氏体,同时细小的碳化物分布在铁素体内;具有良好的强度和韧性,抗拉强度≥750 MPa,屈服强度≥640 MPa,-20℃冲击功≥100 J,各项力学性能指标均满足700L的国标要求。

700MPa high strength automobile girder steel was developed by adopting low carbon microalloying composition design and hot mechanical rolling and tempering process.The microstructures and mechanical properties of the rolled steel plates with different tempering temperature were tested.The results show that the structure of the steel sheet is homogeneous ferrite and sorbite after tempered at 620℃,and fine carbides is distributed in ferrite.The steel sheet has good strength and toughness,the tensile strength is 750 MPa,the yield strength is 640 MPa,the impact work is equal or greater than 100 J at-20℃,and all mechanical properties meet the requirements of 700L national standard.