Petrochemical Design ›› 2025, Vol. 42 ›› Issue (1): 13-16.doi: 10.3969/j.issn.1005-8168.2025.01.004

• DESIGN TECHNOLOGY • Previous Articles    

Causes and Countermeasures for Welding Cracks in 1Cr5Mo Steel Pipelines in Service

Liu Lizhong   

  1. Fujian Refining & Petrochemical Company Limited, Quanzhou, Fujian, 362000
  • Published:2025-03-03

Abstract: The 1Cr5Mo pipelines that have been locally thinned after years of operation in petrochemical units are repaired and replaced. Crack defects easily occur during the welding construction of new and old pipelines. In this article, the causes of crack defects are found out by analyzing the appearance characteristics of cracks, the weld hardness, the chemical composition of base metal and the phase composition of scale on the inner wall of pipelines, as well as the mechanism of weld cracks and the construction process.

Key words: pipeline in service, 1Cr5Mo steel, welding crack, cause analysis