Relation of Thermal Cycle for Simulation to Hydrogen Cold Cracking Susceptibility and Direct Observation of Cracking : Association of Partial Melting and Hydrogen Cold Cracking in Weld Heat-Affected Zone of HSLA Steel (Part I)

概要

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The direct observation of hydrogen bubble evolution and cracking behavior, such as initiation and propagation in HY-80 heat-affected zone was performed using a device with a microscope, and some new understandings were obtained. The site of hydrogen evolution was almost always located at sulfide inclusion and/or liquated grain boundary, and the rate of the hydrogen evolution reached a maximum value at a certain tensile stress and then decreased with an increase of applied tensile stress. As the peak temperature of the simulated heat-affected zone was increased, the cracking morphology changed from transgranular with plastic deformation to intergranular with little plastic deformation, and the stress for cracking to initiate became smaller. To obtain more understanding about the hydrogen cold cracking feature in the HY-80 heat-affected zone, similar experiments were conducted on the SM50B heat-affected zone, but the hydrogen cold cracking susceptibility in SM50B steel was quite different from that in HY-80 steel, and it was independent of the peak temperature of the simulated heat-affected zone.
社団法人溶接学会の論文
1988-04-01