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<p>The mechanical properties of pipeline steel significantly influence the operational safety and service life of underground gas storage (UGS). This study follows results of tensile tests on the base metal (L450-BM) and welds (L450-WM) of L450 pipeline steel, evaluating their strength and ductility alongside analyzing their microstructure and fracture morphology. Using finite element software and based on experimentally measured mechanical properties, fatigue simulation models for the base metal and weld specimens were established to capture the evolution of fatigue life under different loading conditions. Results indicate that the ductility of L450-WM is significantly lower than that of L450-BM, with elongation at fracture being 17.2% for L450-BM and 14.6% for L450-WM. The fracture types are characterized as quasi-cleavage fracture and cleavage fracture, respectively. Both L450-BM and L450-WM exhibit reduced fatigue life with increasing average tensile force and load spectrum amplitude. Under a tensile force of 6.5&#xa0;kN with an amplitude greater than 0.1, the fatigue cycles of L450-WM decreased by nearly two orders of magnitude, reaching only 1.8% of the L450-BM. These findings provide valuable data and theoretical support for material selection and pipeline failure prevention in UGS.</p>

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Evaluation of Mechanical Properties and Fatigue Performance of L450 Pipeline Steel Base Metal and Welds

  • 期刊论文

  • 发表日期：

    2025年9月11日

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  • Jiao Wu,
  • Guochun Zhong,
  • Chen Zhang,
  • Shichang Liu,
  • Peng Li,
  • Lihua Wan,
  • Mujun Long

摘要

The mechanical properties of pipeline steel significantly influence the operational safety and service life of underground gas storage (UGS). This study follows results of tensile tests on the base metal (L450-BM) and welds (L450-WM) of L450 pipeline steel, evaluating their strength and ductility alongside analyzing their microstructure and fracture morphology. Using finite element software and based on experimentally measured mechanical properties, fatigue simulation models for the base metal and weld specimens were established to capture the evolution of fatigue life under different loading conditions. Results indicate that the ductility of L450-WM is significantly lower than that of L450-BM, with elongation at fracture being 17.2% for L450-BM and 14.6% for L450-WM. The fracture types are characterized as quasi-cleavage fracture and cleavage fracture, respectively. Both L450-BM and L450-WM exhibit reduced fatigue life with increasing average tensile force and load spectrum amplitude. Under a tensile force of 6.5 kN with an amplitude greater than 0.1, the fatigue cycles of L450-WM decreased by nearly two orders of magnitude, reaching only 1.8% of the L450-BM. These findings provide valuable data and theoretical support for material selection and pipeline failure prevention in UGS.