特性分布図による溶接熱影響部CTOD靱性の解釈

強度的不均質をもつ鋼溶接部のミクロき裂発生特性に関する研究(第二報)

抄録

To visualize the fracture initiation characteristics in the multipass weld heat affected zone (HAZ), the yield strength distribution map and the CTOD toughness distribution map were drawn up graphically by a computer, based on a series of HAZ simulation test results. The comparison between these computationally estimated property distribution maps and the real HAZ CTOD test result revealed that:
The fracture of the HAZ CTOD specimens was initiated from a peripheral part of a local hard zone (LHZ), which does not always correspond to the most brittle point on the crack front line, and
The critical CTOD value derived by the full-thickness specimen was adequately represented by the local critical CTOD level at its fracture initiation point.
The result of this study suggested that the fracture initiation is prevailed not only by the local brittleness but also by the heterogeneity in strength in the HAZ.