Abstract
In this report, after various processes of machining steel from which residual stresses had been removed perfectly we measured several depths of stressed layers produced by those operations and investigated the correlation between them and the ratio of dimensional changes produced by quenching the specimens. Then, they were measured by both hardness and recrystallization methods which had proved to be better when we had many preparative experiments for measurement.
According to the above results, depth of stressed layer produced by turning at the cutting speed of 20 m/min was the greatest, and those by other machinings i.e. high-velocity turning at the cutting speed of 40.7 m/min, grinding and accurate grinding gradually decreased. It was the least in the case of superfinishing.
Next, we recognized that in proportion to the depth of stressed layers dimensional changes produced by quenching at the constant temperature 850° increased.
Futher, we found that ratio of dimensional changes produced by quenching the specimens which were annealed after machinings was less than those which were only machined.
