Analysis of the ductility dip cracking in the nickel-base alloy welding overlay on heat exchanger tube sheet

•Macro cracks on the weld overlay are caused by the propagation of the ductility dip crack that arises during the welding process.•Improper welding strategy and inappropriate choice of welding material is the root cause of ductility-dip microcrack.•Few actual cases of this type of cracking are discussed in the current research papers. The mechanism and root causes of ductility dip cracking are discussed in detail.