Properties of friction welds between 9Cr-ODS martensitic and ferritic-martensitic steels

Uwaba, Tomoyuki ; Ukai, Shigeharu  ; Nakai, Tatsuyoshi*; Fujiwara, Masayuki*

Friction welding between oxide-dispersion-strengthened-steel (ODS) and ferritic-martensitic 11Cr-0.5Mo-2W, V, Nb steel (PNC-FMS) was examined to investigate the feasibility of the welding of this alloy combination. Forge pressure was varied in the welding test to investigate the effect on the soundness of the weld joint. Post weld heat treatment was necessary for the weld joint because the heat affected zone caused quench hardening in the as-welded condition. The welds were cross-sectioned and examined to determine their metallurgical structure, hardness and tensile strength. Since the heat treatment produced a softening zone near the weld interface, the furnace- cooling rate was investigated at which the softening did not occur. The weld joints were cold rolled and the soundness of the weld interface was determined by the tensile test with the cold rolled weld joints.