Development of Welding Process for Oxide Dispersion Strengthened(ODS) Ferritic Steel

Seki, Masayuki; Ishibashi, Fujio; Kihara, Yoshiyuki; Hirako, Kazuhito*; Tsukada, Tatsuya*

The development of the welding technology for the ODS steel was started in JFY1987. The first welding examination used the tungsten inert-gas (TIG) welding method and the YAG pulse laser welding method. However, the existing fusion welding methods significantly degrade strength at the welded section, because large size of blowholes appears at the weld and induce coagulation of oxides to generate coarser particles. To solve this problem, we have developed pressurized resistance welding (PRW) as a solid phase welding method.The appropriate conditions, e.g. electric current, voltage and contact force, were selected. For the PRW welded specimens, the tensile, internal burst and creep rupture tests were conducted and its integrity was confirmed. In addition, an ultrasonic inspection method has been developed to assure non-destructively integrity of the welding between cladding and end-plug.