TMCP型Q500qENH特厚耐候桥梁钢板的工业试制

Industrial Run to Produce TMCP Processed Q500qENH Weathering Heavy Plate for Bridge

提出一种低碳微合金MnCuNiCrMo钢,测试了其过冷奥氏体连续冷却相变(CCT)曲线,分别研究未再结晶区变形量、冷却速率对其相变行为的影响。使用厚板坯连铸(CC)—钢板控轧控冷(TMCP)工艺流程,在5m宽厚板工业生产线上成功开发出60mm特厚Q500qENH桥梁钢板。开发钢板的显微组织为细密粒状贝氏体(GB)+针状铁素体(AF)+多边形铁素体(PF);横向室温屈服强度大于560MPa,抗拉强度大于660MPa,伸长率大于20%;Z向面缩率大于76%;-40℃下纵向Charpy冲击吸收能量(KV2)大于170J;零塑性温度为-85℃。

A low carbon micro-alloyed MnCuNiCrMo heavy plate steel was proposed to develop 60mm thick plate with yield strength （YS） of 500 MPa and secured low temperature toughness. The effects of pancaking of austenite and cooling rate on continuous cooling transformation （CCT） behavior of the subject steel were investigated. Integrated industrial production trial consisted of continuous casting of thick slab and thermomechanical control processing （TMCP） of heavy plate employing a 5 m width rolling mill was conducted to produce the advanced product. The microstructure of the plate consists of granular bainite （GB）＋acicular ferrite （AF） ＋polygonal ferrite （PF）. The room temperature tensile properties in transverse direction are featured by YS greater than 560 MPa, ultimate tensile strength （UTS） greater than 660 MPa and total elongation greater than 20 pet, meanwhile, the area reduction rate in Z direction greater than 76%. The Charpy V notch （CVN） impact toughness in longitudinal direction is greater than 170J at -40℃, while the nil-ductility transition temperature （NDTT） is at -85℃.