K. Arimoto, Arimotech Ltd., Osaka, Japan; K. Funatani, IMST Inst. Consultant., Nagoya, Japan
Fe-Ni alloy cylindrical specimens were invented in the 1930s for studying residual stresses in through hardened steels, since the alloy induces only martensite during quenching irrespective of cooling speed. Mechanical measuring methods of residual stresses, such as the Sachs method, were applied easily to the induced martensite which is softer than in usual steels. Furthermore, the characteristic of the alloy, not producing diffusion type transformations, was useful to set quench test conditions for controlling thermal and phase transformation strain inductions suitably. Pioneers of the heat treatment simulation also experimented with the alloy for verifying their software. Here, experimental and theoretical studies of residual stresses in the Fe-Ni alloy cylinders were reviewed historically and its origin was explained using the heat treatment simulation.
Summary: Fe-Ni alloy cylindrical specimens were invented in the 1930s for studying residual stresses in through hardened steels, since the alloy induces only martensite during quenching irrespective of cooling speed. Mechanical measuring methods of residual stresses, such as the Sachs method, were applied easily to the induced martensite which is softer than in usual steels. Furthermore, the characteristic of the alloy, not producing diffusion type transformations, was useful to set quench test conditions for controlling thermal and phase transformation strain inductions suitably. Pioneers of the heat treatment simulation also experimented with the alloy for verifying their software. Here, experimental and theoretical studies of residual stresses in the Fe-Ni alloy cylinders were reviewed historically and its origin was explained using the heat treatment simulation.
