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 (
IT
F) were studied in this investigation by using HT50 and 80 steels. The remarkable conclusions are as follows:
(1) The
IT
F 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, " δH
v=(H
v, w-H
v, B)/Hv, B. Furthermore it had a tendency which is raised with an increase of the F
p value, or with a decrease of δH
v-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
IT
F, in which the two basic parameters of F
p, and δH
v 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.
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