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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 technical difficulties of the welding of the elbow supporting ring are analyzed. Using TIG welding, the welding current is 100 ~ 120 A, the groove is designed as a non-equilateral X-shaped, without preheating before welding, without heat treatment after welding. Welding process, the use of special tooling to protect the root of the weld, strict control of the interlayer temperature and weld quality. After welding the weld ray detection, metallographic examination and hardness analysis. The results show that the joint structure is austenite, there is no overheated microstructure in the HAZ and no liquefied film and eutectic phase are found in the intergranular zone. The hardness of the joint is higher than that of the base metal, and no softening in the HAZ occurs. In line with NB / T 47013.1-2015 “non-destructive testing of pressure equipment” Ⅱ grade requirements. Connector has good resistance to hot cracking tendency, corrosion resistance and mechanical properties.