Prediction on cold crack sensitivity using hydrogen embrittlement index measured from in situ slow-strain-rate testing for multipass flux-cored arc weld metals of shipbuilding and offshore steels

To evaluate the cold crack sensitivity of multipass flux-cored arc weld metals, in situ slow-strain-rate testing (SSRT) was performed, and the hydrogen embrittlement (HE) index was quantitatively measured. The HE index was high for the high-strength weld metal under low heat input condition (L-91) and for the low-strength weld metal under high heat input condition (H-71). Cold cracks formed transversely in the window-type restraint weld cracking test under the two welding conditions with high HE indices (L-91 and H-71). The L-81 and H-81 weld metals had the lowest cold crack sensitivity because their HE indices were low; they showed no transverse cracking regardless of the heat input conditions. The HE index of the multipass weld metals, measured through in situ SSRT, was the most important parameter for simulating the cold cracking tendency of window-type restraint weld cracking test.