TIG Dressing Effects on Weld Pores and Pore Cracking of Titanium Weldments

Abstract

Weld pores redistribution, the effectiveness of using tungsten inert gas (TIG) dressing to remove weld pores, and changes in the mechanical properties due to the TIG dressing of Ti-3Al-2.5V weldments were studied. Moreover, weld cracks due to pores were investigated. The results show that weld pores less than 300 μm in size are redistributed or removed via remelting due to TIG dressing. Regardless of the temperature condition, TIG dressing welding showed ductility, and there was a loss of 7% tensile strength of the weldments. Additionally, it was considered that porosity redistribution by TIG dressing was due to fluid flow during the remelting of the weld pool. Weld cracks in titanium weldment create branch cracks around pores that propagate via the intragranular fracture, and oxygen is dispersed around the pores. It is suggested that the pore locations around the LBZ (local brittle zone) and stress concentration due to the pores have significant effects on crack initiation and propagation.

Keywords

• titanium welding
• weld pores
• cracks
• TIG dressing
• ductility