高性能桥梁用钢系列新钢种的性能分析

The Property Analysis of Performance New Steel Grade for High Bridge Steels

对采用超低碳贝氏体钢工艺路线研制的4种新一代高性能桥梁用钢Q345qE（NH），Q420qE（NH），QS00qE（NH）和Q690qE（NH）的力学性能、耐腐蚀性能、屈强比控制和焊接性能进行测试和分析。结果表明：这4种高性能桥梁用钢的强度都达到了GB／T714-2008《桥梁用结构钢》的相关要求，且具有良好的低温韧性和塑性；采用TMCP工艺生产的Q345qE（NH），Q420qE（NH）和Q500qE（NH）钢厚板的屈强比均低于0．85，具有理想的低屈强比；采用TMCP＋回火工艺生产的Q690qE（NH）及QS00qE（NH）钢厚板的屈强比明显提高；Q345qE（NH），Q420qE（NH）和Q500qE（NH）钢的耐腐蚀指数分别为6．105，6，233和6．604，均大于6．0，可以裸露使用；32mm厚Q420qE（NH）钢厚板的韧脆转变温度在-120℃以下，远远低于国内环境温度，其屈强比对国内使用环境下高性能桥梁用钢的韧性没有影响；这4种高性能桥梁用钢具有非常良好的焊接性能，易于施焊，接头和热影响区性能完全满足设计要求。

The mechanical property, corrosion resistance, yield ratio control and weldability for new-gen- eration high performance bridge steel developed by ultra-low carbon bainite process route with steel grade Q345qE （NH）, Q420qE （NH）, QS00qE （NH）, and Q690qE （NH）, were researched. The results show that high performance bridge steel for the above grade has high strength, which meets the standard GB/T 714-2008 ＂Structural Steel for Bridge＂, as well as low temperature toughness and plasticity. The yield ratio of steel grade Q345qE （NH）, Q420qE （NH）, QS00qE （NH） manufactured with TMCP tech- nology, is all less than 0.85, which is ideal. The yield ratio of Q690qE （NH） and QS00qE （NH） manu- facture by TMCP and tempering process is obviously increased. The corrosion resisting index of Q345qE （NH）, Q420qE （NH） and QS00qE （NH） is 6. 105, 6. 233 and 6. 604 respectively which are all greater than 6.0 and can be used without coating. The ductile-brittle transition temperature of Q420qE （NH） with 32 mm thickness is below -120℃, which is much less than domestic atmosphere temperature and its yield ratio has no influence on the toughness of high performanee bridge steel under domestic application environment.