Abstract
It is well known that fracture initiation behaviors is influenced by Hot Straining during weld thermal cycle. In the present report, attention is forcussed to the influence of embrittlement due to weld thermal strain on processes of fracture. The processes of fracture of notched materials, KD32 and HT80 steel, subjected to hot-straining or strain-aging are made observation. Hot straining and strain aging influence not only on initiation and propagation behaviors of ductile fracture. In the materials subjected to hot straining and strain aging, initiation and propagation of ductile crack occur in the range of smaller deformation than in the virgin materials. The mutual relation between the increase in Ti-temperature or the decrease of width of stretched zone and the increase in harolness of notched-material subjected to straining can be observed.
