Abstract
Rutile and anatase TiO2 fluxes were used to investigate the influence of the powdered oxides on the joint penetration ability (JPA) and solidification cracking susceptibility (SCS) in the gas tungsten arc (GTA) welding of type 316L stainless steel (SS). The mechanisms underlying the increase in JPA of GTA welds made with various crystalline phases of TiO2 were also identified. The results indicate that GTA welding with rutile TiO2 (R-TiO2) or anatase TiO2 (A-TiO2) forms a viscous slag over the surface of the weld. The R-TiO2 is more thermodynamically stable than the A-TiO2, leading to a greater improvement in JPA of GTA weld made with A-TiO2. The welding arc action can be ignored and only the convection of the molten pool should be considered in the underlying mechanism for the increase in JPA of GTA weld made with R-TiO2 or A-TiO2. Moreover, the TiO2 assisted GTA welding of type 316L SS was effective in decreasing the SCS.