焼入した鋼のクリープにおよぼす炭素量の影響

抄録

In the previous paper, the microplasticity of hardened ball-bearing steel under sustained twristing moment (shear stress of 1.8∼15.0 kg/mm²) between room temperature and 300°C, had been reported. It was suggested that the total strain increment between designated temperatures (named cumulative flow) of quenched specimens depends upon the carbon concentration of quenched martensite. In the present paper the cumulative flow for quenched carbon steels of various carbon contents was investigated and its dependency on the carbon concentration of martensite was established. For tempered specimens the cumulative flow below tempering temperature was also influenced by the primary carbon concentration. By means of twisting-creep tests, cold-drawn ball-bearing steel also exhibited a tendency fairly resembling that of quenched low-carbon steel.