汽车用600 MPa级热轧高扩孔钢的研制与开发

以一种低碳微合金钢为对象，通过中薄板坯连铸连轧线进行了600 MPa级汽车用热轧高扩孔钢的工业研制与开发。试制结果表明：成品钢板的组织由铁素体和贝氏体组成，铁素体的体积分数约为71.5%，铁素体晶粒尺寸约为5.6 μm，钢板的抗拉强度高于610 MPa，伸长率大于22.0%，扩孔率大于104%，钢板性能满足国家标准要求。同时，对热轧参数和合金元素对产品的组织和性能的影响进行了讨论。

Development of 600 MPa hot rolled strip with high hole expansion ratio for automobile

The development of 600 MPa grade hot rolled strip with high hole expansion ratio for automobile on CSP line was introduced using a low carbon microalloyed steel.The tested results showed that the microstructure of the steel was composed with ferrite and bainite,with the ferrite volume percentage of about 71.5%,and the average ferrite size was about 5.6 μm.The tensile strength was above 610 MPa and the elongation was above 22.0%,the hole expending ratio was above 104%.The properties of this steel satisfied the request of national standard.The effect of hot rolling parameters and alloying elements on microstructure and property were discussed at the meantime.