抄録
The heat treated plain carbon steel, which has been subjected to the tension or the compression load below the yield point, shows various residual strain after unloading, according to the heat treatment conditions, and the author measured the value with the electric resistance wire strain gauge. The amount of this strain is about 10-5. Especially, in the case of tempering at 300°C after quenching, the residual strain appears in the opposite direction to the applied load.
In this experiment, first, the author measured the residual strain of the specimens, which were tempered at 300°C, changing the mode of tensile load and the specimens' diameter. Next, he measured the residual strain of various specimens, which were quenched and tempered at different temperature and subjected to the tension or the compression load. And he investigated the relation between the change of specific volume before and after the load, and the residual strain after unloading. The result shows that these residual strains have some relations with the change of specific volume to be caused by tempering.
