Pressurized Resistance Welding Technology Development in 9Cr-ODS Martensitic Steels

Seki, Masayuki; Kono, Shusaku; Kihara, Yoshiyuki; Kaito, Takeji ; Ukai, Shigeharu  ; Hirako, Kazuhiko*

Welding technology for fuel cladding and end-plugs made of ODS steel has been developed to apply for the fast reactor fuel pin fabrication at Tokai-works of JNC. A pressurized resistance welding (PRW) method is utilized as solid phase welding. The method is based on electrical resistance heating of the components while maintaining a continuous force sufficient to forge weld without melting of the components. The contact force between cladding and end-plug is given by pneumatic-hydraulic system. The welding parameters, e.g. electric current, voltage and contact force, are controlled by a programmable system. The appropriate conditions are selected to be a 700 Kgf contact load with 16 kA current for 20 ms after holding for pre-heating by 6 kA current. For relieving the residual stress, the post-welded heat-treatment is performed in the condition of tempering at 1053 K for 10 min. A metallugically bonded welds has been formed by the PRW method, keeping the original dispersed distributio