液化气球罐焊缝H_2S应力腐蚀裂纹的返修补焊

Repairing and Mending Welding of Cracking Seam Caused by H_2S Corrosion Stress on Liquefaction Gas Spherical Tank

对宁夏炼油厂一台200m3低合金钢球罐H2S应力腐蚀裂纹采用气刨打磨后补焊的返修方法表明，碳弧气刨时的骤热不会使裂纹向纵深扩展，只是必须在补焊前将返修部位焊缝两侧各100mm范围内打磨至完全露出金属光泽，以便彻底消除裂纹源，避免补焊时再产生新的微小裂纹。若返修深度不大于罐壁厚度的二分之一，则不必进行射线探伤检查，只须进行100％的超声波检查，在水压试验前后对返修部位进行100％磁粉探伤则是非常必要的。

The mending welding after gas gouging and grinding is used for repairing cracking seams caused by H2S corrosion stress in low alloy steel spherical tank of 200 m3 in Ningxia refinery. The heat released by carbon gas gouging can not developed the cracking seams. Grinding along two sides of the 100 mm seam is done to show seam's light metal to avoid new seam after mending. X-ray is not needed if mending depth is less than half of the wall thickness and it only needs 100% ultrasonic flaw detecting. And 100 % of magnetic powder detecting is needed before and after water pressure test.