文献类型：期刊文献

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

作者：Liu, Tong[1];Wang, Qiongqi[1];Guan, Kaishu[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2023

卷号：147

外文期刊名：ENGINEERING FAILURE ANALYSIS

收录：;EI(收录号：20231113710322);WOS:【SCI-EXPANDED(收录号:WOS:001009420900001)】；

语种：英文

外文关键词：Ductility dip cracking; Nickel-base alloy; Weld overlay; Heat exchanger

摘要：In this paper, the cracking failure of the weld overlay of the heat exchanger tube sheet was analyzed. The weld overlay, welded by ErNiCrMo-3, cracked several times within a short period after the heat exchanger was put into operation, resulting in internal leakage from the heat exchanger. The failure causes are investigated by means of macroscopic observation, metallographic analysis, scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) analysis, and hardness test. The synthetical analysis shows that a sudden drop in ductility of the weld overlay material occurs at the time of microcracking, and a phenomenon similar to grain boundary sliding is observed in the fracture morphology image at high magnification. Therefore, the microcrack on the weld overlay is a kind of ductility dip crack at elevated temperatures. Improper welding strategy and inappropriate choice of welding material is the root cause of ductility-dip microcrack during the welding process. The microcracks on the weld overlay propagate during the operation of the heat exchanger, causing it to leak several times in a short period.