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<p>G115 martensitic steel (08Cr9W3Co3VNbCuBN) is an ideal material for high-pressure components operating at 630-650&#xa0;°C in advanced ultra-supercritical (A-USC) power plants. Shielded metal arc welding (SMAW) technology is a critical process in the fabrication of key structural components in A-USC units. However, the currently available welding electrodes compatible with G115 martensitic heat-resistant steel exhibit insufficient comprehensive performance. After welding, alloy elements in the weld tend to segregate, making it prone to cracking and exhibiting low impact toughness. This study focuses on SMAW of G115 martensitic heat-resistant steel, conducting electrode composition design, deposited metal testing, and process performance evaluations, ultimately developing a low-hydrogen basic electrode with excellent operability and physicochemical properties suitable for various applications. The microstructural and mechanical properties of welded joints were investigated under varying parameters, including preheating temperature, heat input, interlayer temperature, post-weld heat treatment (PWHT) temperature and duration. The optimal welding process was identified, balancing safety, efficiency, stability, and reliability. The best-performing welding parameters are as follows: preheating temperature of 200&#xa0;°C, heat input of 15&#xa0;kJ/cm, interlayer temperature of 225&#xa0;°C, PWHT temperature of 770&#xa0;°C, and PWHT duration of 4&#xa0;h. Welded joints produced under these conditions exhibit a room-temperature tensile strength of 721&#xa0;MPa, high-temperature tensile strength of 360&#xa0;MPa, room-temperature impact energy of 86&#xa0;J in the weld zone, and 72&#xa0;J in the heat-affected zone (HAZ), along with qualified bending performance. This study successfully developed welded joints with physicochemical properties closely matching those of the base G115 steel. The findings provide a reliable foundation for the practical engineering implementation of G115 steel in advanced ultra-supercritical power generation systems.</p>

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Development of Electrodes for Shielded Metal Arc Welding of G115 Steel and Investigation of Microstructure and Mechanical Properties

  • 期刊论文

  • 发表日期：

    2026年1月27日

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  • Qiushi Li,
  • Sanbao Lin,
  • Yangyang Fan,
  • Qihao Chen,
  • Qinghe Guan,
  • Xiangjiu Xu

摘要

G115 martensitic steel (08Cr9W3Co3VNbCuBN) is an ideal material for high-pressure components operating at 630-650 °C in advanced ultra-supercritical (A-USC) power plants. Shielded metal arc welding (SMAW) technology is a critical process in the fabrication of key structural components in A-USC units. However, the currently available welding electrodes compatible with G115 martensitic heat-resistant steel exhibit insufficient comprehensive performance. After welding, alloy elements in the weld tend to segregate, making it prone to cracking and exhibiting low impact toughness. This study focuses on SMAW of G115 martensitic heat-resistant steel, conducting electrode composition design, deposited metal testing, and process performance evaluations, ultimately developing a low-hydrogen basic electrode with excellent operability and physicochemical properties suitable for various applications. The microstructural and mechanical properties of welded joints were investigated under varying parameters, including preheating temperature, heat input, interlayer temperature, post-weld heat treatment (PWHT) temperature and duration. The optimal welding process was identified, balancing safety, efficiency, stability, and reliability. The best-performing welding parameters are as follows: preheating temperature of 200 °C, heat input of 15 kJ/cm, interlayer temperature of 225 °C, PWHT temperature of 770 °C, and PWHT duration of 4 h. Welded joints produced under these conditions exhibit a room-temperature tensile strength of 721 MPa, high-temperature tensile strength of 360 MPa, room-temperature impact energy of 86 J in the weld zone, and 72 J in the heat-affected zone (HAZ), along with qualified bending performance. This study successfully developed welded joints with physicochemical properties closely matching those of the base G115 steel. The findings provide a reliable foundation for the practical engineering implementation of G115 steel in advanced ultra-supercritical power generation systems.