Study of Repair Performance of Pipeline System.

To repair a pipeline system, an automatic welding process is used to carry out the sleeve welding. In this study, the repair performance of the sleeve was studied, and the research results will help improve the repair quality of pipeline systems in the future. The results show that the tensile strength of the fillet weld was lower than the minimum nominal tensile strength of X65 steel. There were small cracks at the root of the fillet weld. The fracture surfaces of the side bend test of the butt weld and the notching hammer break test of the fillet weld indicated defects to different degrees. The tensile tests of butt welds indicated breaks in the base metal, and the average tensile strength was 587 MPa. The ductile-brittle transition temperature of the butt weld and the fusion line ware both lower than −60°C , and the average crack tip opening displacement (CTOD) values of −10°C fracture toughness tests of the butt weld and heat affected zone were 0.181 and 0.510 mm, respectively. [ABSTRACT FROM AUTHOR]