Scholarlink

<p>The stress corrosion cracking (SCC) failure of a cold-formed S30408 stainless steel head in a methanol filter was investigated. The head leaked during service in a methanol environment containing H<sub>2</sub>S and chlorides. Macroscopic inspection, metallographic examination, SEM, EDS, and hardness mapping were employed to identify the root cause of the failure. The results revealed that the cracks originated from the inner surface and propagated outward in a typical transgranular and branched manner. Microstructural analysis indicated that cold pressing without subsequent solution heat treatment induced the transformation of austenite to deformation-induced martensite. This lack of annealing led to severe work hardening and significant localized residual stress, evidenced by an abnormal hardness gradient increasing up to 427&#xa0;HV near the cracking zone. EDS analysis confirmed the enrichment of corrosive S and Cl on the fracture surface. It is concluded that the leakage was caused by transgranular SCC, driven by the synergistic effect of high cold-forming residual stresses, the presence of susceptible deformation-induced martensite, and the corrosive Cl/S-containing methanol medium. To prevent such failures, it is strictly recommended that complete solution annealing must be performed after cold forming to eliminate residual stresses and restore a fully austenitic microstructure.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Failure Analysis of a 304 Stainless Steel Methanol Filter Head: Stress Corrosion Cracking Induced by Cold Forming and Cl/S Environment

  • 期刊论文

  • 发表日期：

    2026年7月29日

查看全文
  • Min Xu,
  • Zuowen Jiang,
  • Zhenxi Sun,
  • Xiangjian Zhu

摘要

The stress corrosion cracking (SCC) failure of a cold-formed S30408 stainless steel head in a methanol filter was investigated. The head leaked during service in a methanol environment containing H2S and chlorides. Macroscopic inspection, metallographic examination, SEM, EDS, and hardness mapping were employed to identify the root cause of the failure. The results revealed that the cracks originated from the inner surface and propagated outward in a typical transgranular and branched manner. Microstructural analysis indicated that cold pressing without subsequent solution heat treatment induced the transformation of austenite to deformation-induced martensite. This lack of annealing led to severe work hardening and significant localized residual stress, evidenced by an abnormal hardness gradient increasing up to 427 HV near the cracking zone. EDS analysis confirmed the enrichment of corrosive S and Cl on the fracture surface. It is concluded that the leakage was caused by transgranular SCC, driven by the synergistic effect of high cold-forming residual stresses, the presence of susceptible deformation-induced martensite, and the corrosive Cl/S-containing methanol medium. To prevent such failures, it is strictly recommended that complete solution annealing must be performed after cold forming to eliminate residual stresses and restore a fully austenitic microstructure.