Abstract
A new test was developed to evaluate the cracking sensitivity of thick plates based on the strong constraint conditions during the welding process. A typical application of the new test on assessing the cracking sensitivity of Q345R container steel was also investigated. The surface crack rate (δ) and the cross-section crack rate (ζ) both increased when setting the gap narrower. Crack rate and crack length both increased with increasing restraint stress. Under the critical constraint stress, the experimental results show that the welding heat input has no significant effect on crack sensitivity. With increasing carbon equivalent, the crack length and crack rate both increased. The aggregation of S and P was found near the crack, and the oxygen content was high. The fracture showed the characteristics of dendrites and microcrack, which was approved as a solidification crack.

Key words
rib plate restraint crack sensitivity test, numerical simulation, residual stress, critical constraint stress, crack sensitivity, solidification cracking

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