Microstructure and defect of titanium alloy electron beam deep penetration welded joint
(1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
2. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China)
2. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China)
Abstract: The microstructure, phase composition and cold shut defect of thick titanium alloy electron beam welded joint were studied. The results showed that the microstructure of weld zone was composed of α′ phase; the heat affected zone was divided into fine-grained zone and coarse-grained zone, the microstructure of fine-grained zone was primary α phase + β phase + equiaxed α phase, and the microstructure of coarse-grained zone was primary α phase + acicular α′ phase; the microstructure of base metal zone basically consisted of primary α phase, and a small amount of residual β phase sprinkled. The forming reason of cold shut was analyzed, and the precaution of cold shut was proposed.
Key words: TA15 titanium alloy; electron beam welding; microstructure; phase composition; cold shut defect; weld zone; heat affected zone