抄録
In order to obtain the fundamental concept of the "press-tempering (or heat-setting)" method which was applied to correct the distortion of steels due to hardening, the plastic deformation of steels by heating under loads and the mechanical properties of these steels as affected by such deformation were studied.
As the specimens, the steels which contained 0.6% carbon and had been variously heat-treated were used.
The results were as follows:
1. The hardened steel showed an abnormally large plastic deformability during its tempering. The higher the temperature, the larger was the deformability.
2. In the hardened-tempered steel, such deformability appearred during heating at the temperature which wag bigher than that at which it had been tempered.
3. The annealed steel had no such abnormal deformability.
4. The magnitude of such abnormal defomation was proportional to the applied load and had a closer relation with the hardness variation during the process than with the hardness itself.
5. The influences of such deformation on the progress of transformation were found in the mechanical properties of steels after these treatments.
6. As the cause of such abnormal deformability, the appearance of so-called "position-change plasticity" accompanying the precipitation of the cementite during the tempering was presumed.
