WES 2808 for brittle fracture assessment of steel components under seismic conditions Part-IV: Change in mechanical properties and fracture toughness of steel weld HAZ by pre-strain

摘要

Brittle fracture of the welded steel structures during an earthquake is reported to be caused mainly by dynamic and cyclic large strain. However, effect of pre-strain to fracture toughness of the welded joint, especially heat affected zone (HAZ) was not reported enough. In this paper, effect of pre-strain in HAZ tensile properties and critical CTOD was studied by using the simulated HAZ specimens of 490MPa class steel. Change in tensile properties of simulated HAZ by pre-strain was as well as that of base metal. The amount of change in strength of simulated HAZ was possible to describe by the same numerical formula as the base metal. In addition, the amount of temperature shift at critical CTOD of 0.1mm of simulated HAZ by the pre-strain was as well as that of base metal which has the same amount of the change in flow stress by the pre-strain.