1000MPa级水电高强钢中厚板焊缝开裂原因研究

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中图分类号：TG406

Abstract： During the manufacturing stage of a penstock in a hydropower project， nondestructive testing performed 48 hours after submerged arc welding revealed the presence of a single transverse crack in the longitudinal weld seam. Sampled specimens were systematically examined through macroscopic observation， metallgraphic analysis，and scanning electron microscopy（SEM） to investigate the crack’s origin and characteristics.The results indicate thatthe crack exhibits typical features of hydrogen-induced cold cracking，includinga mixed fracture morphology comprising intergranular and dimpled pattrns in certain regions，along with high hardness in the crack initiation zone，which is associated with localized hydrogen enrichment and the reheated weld microstructure.The study further demonstrates that hydrogen accumulation and stress concentration during multi-pass welding are the primary causes of crack formation. Based on these findings，process improvements were proposed，such as increasing the preheating temperature to 150 （204号 C with a one-hour holding time，enhancing moisture protection of the flux，and implementing post-weld dehydrogenation heat treatment at 200～250° . These measures efectively suppressed hydrogen-induced cracking，providing important technical support for ensuring welding quality and structural integrity in highstrength steel hydropower applications.

Key words： 1000MPa hydropower high-strength steel；welding；failure analysis；hydrogen-induced cracking

0 前言

水力发电是一种将水能转化为电能的清洁能源技术，其在发电过程中几乎不产生污染物，具有显著的环保优势。（剩余5405字）