The brittle fracture tests were performed to examine how the decrease of the residual stress due to the stress-relieving and the resultant quality change would influence on the brittle fracture initiation characteristics and a full consideration was taken as to whether or not the stress-relief treatment is suitable for welded steel structures to ensure their reliability.
While the brittle fracture initiation characteristics after the stress-relieving were improved by relieving the residual stress due to welding, the notch toughness of welded joints was reduced by the stress-relief treatment.
Consequently, the merit and the demerit were offset, and it was not much expected that the brittle fracture initiation characteristics were effectively improved by the stress-relief heat treatment.
