Q500qENH高性能耐候钢在高架桥工程焊接技术与应用

耐候钢在国内迅速发展，但大多数使用Q345等级以下耐候钢，Q500等级及以上的耐候钢在工程上应用的比较少。文中在对国内耐候钢桥梁进行全面梳理的基础上，依托G109线(忠和傅家窑立交至八里湾)改扩建工程钢结构桥梁项目，对Q500qENH高性能耐候钢及相应焊材的耐腐蚀性能、碳当量等进行计算，分析其防腐和焊接性能。结果表明，钢材和焊接材料耐大气腐蚀系数(I)均大于6，说明其耐腐蚀性能良好；钢材碳当量(CE)大于40%，说明钢材强度增加的同时其焊接性能受到一定的影响；同时对Q500qENH高性能耐候钢采用焊条电弧焊和埋弧焊进行施焊，并进行外观检查、超声检测、力学性能试验及宏观金相试验等焊接工艺评定检验，分析和评价其焊接性能，总结出适用于Q500qENH高性能耐候钢的焊接工艺方法和焊接参数，以期为类似工程项目的焊接施工提供经验借鉴。 创新点： 采用Q500qENH高强度耐候钢作为钢结构组合梁下翼缘板，并分析总结适用于Q500qENH高强度耐候钢焊接工艺方法。

Research and application of welding technology of Q500qENH high performance weathering steel in viaduct engineering

At present, weathering steels are developing rapidly in China, but most of them are used below Q345 grade, while weathering steels of Q500 grade and above are rarely used in engineering in China.Based on a comprehensive review of domestic weathering steel bridges, this paper calculates the corrosion resistance and carbon equivalent of Q500qENH high-performance weathering steel and corresponding welding materials, and analyzes their corrosion resistance and weldability, relying on the steel structure bridge project of G109 line reconstruction and expansion project, after calculation, the atmospheric corrosion resistance coefficient(I)of steel and welding materials is greater than 6, which indicates that the corrosion resistance is good, and the carbon equivalent(CE)of steel is greater than 40%, which indicates that the weldability of steel is still affected to some extent while the strength of steel increases.At the same time, the welding procedure of butt joint of Q500qENH high-performance weathering steel is evaluated, and manual arc welding and submerged arc welding are used re-spectively.Then, the welding procedure evaluation and inspection methods such as appearance evaluation inspection, ultrasonic testing, mechanical property test and macroscopic metallographic test are used respectively to analyze and evaluate its welding performance, and the welding procedure and welding parameters suitable for Q500qENH high-performance weathering steel are summarized, so as to provide experience and reference for the welding construction of similar projects. Highlights: In this paper, Q500qENH high-strength weathering steel is used as the lower flange plate of steel composite beam, and the welding process method suitable for Q500qENH high-strength weathering steel is studied and summarized.