A new structure of 1+2 was designed in friction stir welding(FSW)of Al alloy sheet with unequal thickness:a specific sheet with similar composition of base metals(BMs)was placed under the thinner sheet as the supporti...A new structure of 1+2 was designed in friction stir welding(FSW)of Al alloy sheet with unequal thickness:a specific sheet with similar composition of base metals(BMs)was placed under the thinner sheet as the supporting sheet so that the BM surfaces could be on a plane.The BMs can also be fully penetrated weld with a stirring pin longer than the thickness of the thin sheet.2 mm and 1.5 mm thick Al alloy sheets were welded by FSW,and parameters were optimized.The highest welding strength reached 96.07%of the thin base metal.Although a slight thinning phenomenon occurred at the edge of the nugget on the retreating side,the specimen still fractured in the heat-af-fected zone.展开更多
During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing...During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.展开更多
基金Project was supported by National Key Research and Development Program of China(2022YFB 4600900)the National Natural Science Foundation of China(Grant No.52275313)the Fundamental Research Funds for the Central Universities(Grant No.DUT21LAB133).
文摘A new structure of 1+2 was designed in friction stir welding(FSW)of Al alloy sheet with unequal thickness:a specific sheet with similar composition of base metals(BMs)was placed under the thinner sheet as the supporting sheet so that the BM surfaces could be on a plane.The BMs can also be fully penetrated weld with a stirring pin longer than the thickness of the thin sheet.2 mm and 1.5 mm thick Al alloy sheets were welded by FSW,and parameters were optimized.The highest welding strength reached 96.07%of the thin base metal.Although a slight thinning phenomenon occurred at the edge of the nugget on the retreating side,the specimen still fractured in the heat-af-fected zone.
文摘During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.
