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通过设计合理的化学成分,采用铁水预处理→120t转炉→LF精炼→FTSR(Flexible Thin Slab Rolling,灵活的薄板坯连铸连轧)连铸机(87.5mm厚薄板坯)→2机架粗轧+5机架精轧→卷取工艺流程,借助全流程TMCP(Thermo Mechanical Control Process,热机械控制工艺),成功生产了610MPa级汽车大梁钢。检验结果表明:钢板组织为铁素体+贝氏体+少量马氏体和残余奥氏体组元,晶粒尺寸2.08μm;板卷各项力学性能均能满足要求。对冲击断口做扫描电镜发现,冲击断口为韧性断口,且韧窝底部有球形CaS质点。
Through the design of reasonable chemical composition, hot metal pretreatment → 120t converter → LF refining → FTSR (Flexible Thin Slab Rolling) continuous casting machine (87.5mm thick slab) → 2-stand rough rolling +5 mill finishing → coiling process flow, with the full flow TMCP (Thermo Mechanical Control Process, thermo-mechanical control process), successfully produced 610MPa-class automobile girder steel. The test results show that the microstructure of the steel plate is ferrite + bainite + a small amount of martensite and retained austenite, and the grain size is 2.08μm. The mechanical properties of the coil can meet the requirements. Scanning electron microscopy of the impact fracture found that the impact fracture toughness fracture, and the bottom of the dimple spherical CaS particles.