1954 Volume 23 Issue 9-10 Pages 188-191
In order to specify the notch toughness of steels the authors recently proposed the adoption of the criterion :
φ=(maximum load)/(maximum load-point deflection)
at room temperature on the notched slow bending test.
In this report the behaviors of φ under three kinds of deflection rates were investigated, using the V-type standard charpy specimens, in connection with the notch toughness of materials. As the results of this experiment, the behaviors of φ were found as follows:
(a)φ value remains constant within certain temperature range into which room temperature is included.
(b) The larger deflection rate causes the transition temperature and φ value of material to be higher. And thus the larger φ value is connected with the higher transition temperature.
Consequently the presumption of the notch toughness of materials by φ value in the notched slow bending test could be substantiated in the case of various deflection rates.