低裂纹焊接敏感性耐候桥梁钢Q500qENH的研发

Research and Development of Low Crack Welding Sensitivity and Weatherproof Bridge Steel Q500qENH

为了满足低裂纹焊接敏感性耐候桥梁钢Q500qENH中厚板的各项质量要求,在生产试验条件下,采用低碳当量成分设计、双VD+精炼冶炼、连铸浇铸、控轧控冷、热处理工艺,运用晶粒细化、固溶强化、析出强化等手段对20～56 mm Q500qENH耐候桥梁板的研发工艺进行了试验研究,结果表明通过合理的成分设计、严格的冶炼、连铸浇注和控轧控冷、调质相结合的工艺路线,成功研制出Q500qENH中厚板,各项质量指标检测显示:钢板成分控制得当,耐大气腐蚀性能良好;钢板组织均匀、晶粒细化各项性能指标富裕量较大; Z向数据优异,钢板具有良好的抗层状撕裂性能;钢板内部探伤质量优异,宽板拉伸止裂试验数据良好,钢板具有优异的止裂性能。

In order to meet bridge Q500qENH heavy plate, every quality requirement for low crack sensitivity weatherproof during production test low CEQ chemical composition design, double VD＋LF melting, continuous casting, TMCP, heat treatment process, grain refinement, solid solution strengthening and precipitation strengthening were adopted for the research and development of 20-56 mm Q500qENH weathering-resistance bridge plate. The results show that heavy plates of Q500qENH are successfully produced after reasonable design of the composition, strict procedures of smelting, casting and TMCP combined with quenching and tempering, and every test data shows that the chemical composition is well controlled, weathering -resistance properties are good; structure of steel plates is even, grain refinement indexes are with rich margins; test result of through-thickness characteristics is excellent, properties of anti-lamellar-tearing of steel plates is good; The UT test result is excellent, data of tensile crack-arrest is good and steel plates are of good atmospheric corrosion resistance.