抄録
By sectioning Charpy specimens with various types of notches from Mn-Mo steel for reactor pressure vessels and recording the relationship between load and time during impact, the energy absorbed in the Charpy test was analyzed. The size effect of specimen width on the transition behaviour was also examined.
As a result of these, it was found that the transition in the present standard specimens was able to be divided into six temperature regions as reported in the previous paper. Furthermore, the temperature at the shoulder of the transition curve (\simeqTr100s) is considered to be important as a transition temperature because the energies divided have a tendency to reveal a peak value near this temperature range.
Although a linear relationship was observed between the ductility transition temperature and the size of specimen width in the standard specimen, the size effect on the propagation transition temperature was not observed clearly. Similarly, in the crack-propagation type specimens such as press notch, press-boundary notch and low-blow test specimens, the size effect was not observed. Such an effect rather appeared in the gradient from the shoulder of the transition curve in the standard specimens; and the temperature at the shoulder (\simeqTr100s) was not affected by the specimen size. Therefore, this temperature is considered to be important as a crack-propagation transition temperature when correlations with a large specimen test are studied.
