Abstract
The effects of bead width, hardness in electron beam (EB)-weld metal or shape of test specimen on the fracture path transition temperature in Charpy impact test (ITF) were studied in this investigation by using HT50 and 80 steels. The remarkable conclusions are as follows:
(1) The ITF for the E13-weld metals tended to be raised in general with an increase of ab parameters, weld heat input, depth of V notch in impact test specimen or annealing temperature for the welds.
(2) The ITF was basically influenced by the two main parameters, that is, "Fracture path parameter, " Fp=dB/h and "Hardenability parameter, " δHv=(Hv, w-Hv, B)/Hv, B. Furthermore it had a tendency which is raised with an increase of the Fp value, or with a decrease of δHv-value.
(3) The isothermal line for ITF; 100°C was separately made clear on the HT50 and 80 weld metals by means of the settlement of ITF, in which the two basic parameters of Fp, and δHv are used.
(4) A special attention should be paid for the decision in the size of Charpy test specimen in order to investigate the true impact toughness of the EB-weld metal which has a narrow head width and a high hard-ness. Moreover the criterion for the decision of it was individually established on the EB-weld metals of HT50 and 80 steels in this investigation.
