成型性和焊接性优良的超高抗拉强度钢的开发

概述了JFE开发并商业化生产成形性和焊接性均优良的780—1470MPa超高强度系列冷轧钢板。该系列钢板可实现汽车减重，提高碰撞安全性能。该系列钢板是JFE采用自主开发的WQ—CAL（水淬-连续退火生产线）工艺生产的，采用该工艺可以大幅降低钢中合金元素的添加量。其中新开发的1180MPa级抗拉强度钢板的伸长率得到大幅提高，是传统相同级别钢板的1．5倍，与980MPa级钢相同，且其拉伸凸缘性也与980MPa级钢相当。另外，1180MPa级钢的加工淬透性和烘烤硬化性也十分优良，完全可以替代热冲压部件。新开发系列钢可用于白车身结构件，如中梁（加强件）、保险杠、座椅结构架、座椅横挡及座椅部件（如机械锁扣）等多种用途。

NEWLY DEVELOPED ULTRA-HIGH TENSILE STRENGTH STEELS WITH EXCELLENT FORMABILITY AND WELDABILITY

JFE Steel has developed and commercialized ultra- high tensile strength steel series from TS780 MPa to 1 470 MPa with excellent formability and weldability which reduces weight and increases safety in collision when they are applied to the reinforcement parts around a cabin. Those ultra - high ten- sile strength steels are developed by applying JFE Steelg own technology, continuous annealing line water -quenching facilities which greatly contribute to reduce alloy elements in the steel. Especially, the TSll80 MPa steel which is expected to expand in application, excels in elongation. It is 1.5 times larger than the conventional one which is the same level with 980 MPa, and stretch flangeability has also been achieved as the same level with TS980 MPa. Its remarkable work -hardenability and bake -hardenability make it possible to replace hot - stamping parts. Newly developed steels can be used for the automobile＇s body structural parts such as center pillars （reinforcements）, bumper reinforcements seat frames, seat rails, seat parts（ mechanical clinches）.