球状黒鉛鋳鉄による鋼管の鋳ぐるみ接合について

抄録

  Cast bonding of steel pipes coated with Ni-P alloy plating by ductile cast iron was studied. Bonding conditions were examined by tensile strength tests, hydraulic pressure test, observations by microscope and EPMA. Bonding condition was good judging from the results of strength and hydraulic pressure tests, and the structure of the bonding part was good judging from observations by microscope and EPMA. Results of line analysis on Ni and P by EPMA showed that Ni and P were sufficiently diffused in the cast iron and the steel pipe, so there was no segregation of steadite and it showed that there was good diffusion bonding between the steel pipe and the cast iron. This process was applied to fin tubes of ships and it is planned to be used in other parts as well.