首钢Q420qENH高性能耐候桥梁钢板的开发

针对传统桥梁钢板强度低,冲击韧性、焊接性能、耐蚀性能差的问题,首钢公司采用低碳成分设计、添加Ni、Cr、Cu耐候元素以及Mo、Nb元素,并优化了轧制和水冷工艺,开发出具有强韧性匹配和良好耐候性的Q420qENH耐候桥梁钢板。对Q420q ENH钢板的显微组织、力学性能进行了检测,同时采用周期浸润加速腐蚀试验对Q420qENH耐候桥梁钢板和Q420qE普通桥梁钢板的腐蚀失重和腐蚀速率进行了对比分析,研究了Q420qENH钢板的锈层形貌及成分。结果表明:Q420qENH耐候桥梁钢板组织为细小的M-A岛粒状贝氏体、准多边形铁素体和针状铁素体的混合组织,具有高强度、低屈强比和良好的低温韧性;其表面生成结构致密的α-FeOOH锈层,能够阻止钢板被进一步腐蚀,因此相同条件下其耐大气腐蚀性能是Q420qE普通桥梁钢板的2倍以上。

Development of high-performance Q420qENH weathering bridge steel plate in Shougang

In view of low strength,bad properties of impact toughness,welding and corrosion resistance of traditional bridge steelplate, Q420qENH weathering bridge steel plate with good matching of strength and toughness and weather resistance was developed in Shougang by adopting low C composition design and adding Ni, Cr, Cu weather resistant elements as well as Mo and Nb elements, optimizing rolling and water-cooling processes. The microstructure and mechanical properties of the Q420qENH plate were tested. The corrosion loss and corrosion rate of Q420qENH weathering bridge steel plate and Q420qE ordinary bridge steel plate were compared and analyzed by periodic accelerated corrosion test. The morphology and composition of rust layer of the Q420qENH plate were studied. The results show that the microstructure of Q420qENH weathering bridge steel plate is a mixture of granular bainite with small M-A islands,quasi-polygonal ferrite and acicular ferrite, which has high strength, low yield ratio and good low temperature toughness. After periodic corrosion testing, α-FeOOH with dense structure is formed on the surface of Q420qENH weathering bridge steel plate, which can prevent further corrosion of plate.Under the same conditions, atmospheric corrosion resistance of Q420qENH weathering bridge steel plate is more than 2 times that of Q420qE ordinary bridge plate.