We have performed charpy impact tests of specimens with different'notch radius, which were machined .out from three mild steels having 0.22, 0.29, and 0.40% Cu content respectively.
We have obtained the following' facts:
(1) Using the experimental results by Rinebolt & Harris, and Williams to eliminate the effects of C, Mn, and P on the transition temperature, we have found that the transition temperature is lowered, as the Cu content increases (in the range 0.22-0.40%).
(2) The formula formerly proposed by the authors to give the relation between the notch geometry and the transition temperature, or the absorbed energy at low temperature matches fairly well with the present experimental results.
(3) Furthermore we have got a relation between the absorbed energy at 0°C and the transition temperature determined from 2.6 kg-m/cm² energy level.