400MPa级热轧碳素结构钢筋盘条的生产实践

Production Practice of 400 MPa Grade Hot Rolled Carbon Constructional Steel Rebar Coil

张钢采用控轧控冷技术生产400MPa级热轧碳素结构钢筋盘条,控制轧制采用二阶段变形制度;轧制中间阶段的控制冷却采用设定精轧入口温度和减定径入口温度,轧后一次控制冷却采用设定吐丝温度,二次控制冷却采用开启前6台风机,开口度为85%,三次冷却采用空冷。产品组织为铁素体+珠光体,晶粒细小均匀,屈服强度448.6MPa,抗拉强度650.8MPa,伸长率29.5%,完全满足标准要求。

400 MPa grade hot rolled carbon constructional steel rebar coil is produced by controlled rolling and controlled cooling technology in Zhangdian Steel and the controlled rolling is adopted two-stage deformation system. The controlled cooling in the intermediate stage of rolling makes use of setting finishing rolling entrance temperature and the reducing sizing entrance temperature, the first controlled cooling after roiling makes use of setting spiting wire temperature, second controlled cooling makes use of 6 first blast engines with 85% opening degree, third controlled cooling makes use of air. The microstructure of product is ferrite and pearlite with tiny and even crystal grain. The yield strength is 448.6 MPa, the tensile strength is 650.8 MPa and the elongation is 29.5%, fully satisfying the requirement of the national standard.