Analysis and Repair of Cracks in Welding Tee of Main Steam Pipelines in Thermal Power Units

Abstract During the maintenance process of a certain thermal power unit, multiple intermittent cracks were found in the Y-type welding tee weld of the main steam pipeline. This paper expounds the detection situation and treatment process of the welding tee weld, and analyzes the material, operating condition, structural characteristics and stress state of the test parts. The results show that the cracks are reheat crack, which is greatly related to the material. In addition, the structure of the welding tee is not reasonable, which increases the stress of the weld and accelerates the generation and expansion of the cracks. In this paper, the optimization suggestions are put forward for the welding repair and heat treatment process of the main steam pipeline, and the defects are successfully treated, which provides a reference for the detection and repair of the weld defects of similar and thick-wall pipe fittings.