燃机弯管支撑环焊接工艺与接头性能研究

Study on Welding Process and Joint Performance of Elbow Support Ring of Gas Turbine

分析了燃机弯管支承环的焊接技术难点。采用钨极氩弧焊,焊接电流为100~120 A,将坡口形式设计为不等边X型,焊前不预热,焊后不进行热处理。焊接过程中,采用专用工装保护焊缝根部,严格控制层间温度与焊缝质量。焊后对焊缝进行射线探伤、金相检测与硬度分析。结果表明,接头组织均为奥氏体,热影响区不存在过热组织,晶间未发现液化薄膜和低熔点共晶物;接头硬度高于母材部分,未出现热影响区软化现象;焊接质量符合NB/T 47013.1-2015《承压设备无损检测》Ⅱ级合格要求。接头具有较好的抗热裂倾向、耐蚀性和综合力学性能。

The welding technical difficulties of elbow supporting ring of gas turbine were analyzed. TIG welding with welding current of 100-120 A was adopted, the groove was inequilateral X-shape, and no preheating before welding and no heat treatment after welding were carried out. The special tool was used to protect the weld root, and the temperature between layers and weld quality were strictly controlled during welding. The X-ray inspection, metallographic observation and hardness test of the weld were carried out after welding. The results show that the microstructure of welded joint is austenite and there is no overheating microstructure in heat affected zone, and no liquid film and low melting point eutcctic are found between the crystals. The hardness of welded joint is higher than that of base metal, and there is no softening of heat affected zone. The welding quality meets NB/T4730.1-2015 If-level eligibility criteria, and the welded joints have good resistance to hot tearing tendency, corrosion resistance and mechanical properties.