Scholarlink

<p>Achieving through-thickness uniformity in microstructure and properties remains a key challenge in thick-section welds fabricated using high-energy-density joining processes. In this study, detailed microstructural characterization and property evaluations were performed on a full-penetration 18-mm-thick autogenous electron beam weld in UNS S32205 duplex stainless steel. The weld joint exhibited a tapered fusion-zone morphology characteristic of keyhole welds, with the fusion-zone width decreasing from approximately 8&#xa0;mm in the upper region to 2&#xa0;mm at the weld root. Pronounced through-thickness microstructural heterogeneity developed in the fusion zone. The upper and middle regions exhibited a more favorable ferrite–austenite balance, whereas the lower region showed significantly suppressed ferrite-to-austenite transformation, resulting in a higher ferrite fraction and increased susceptibility to Cr-nitride precipitation. This phase heterogeneity governed the local low-temperature impact toughness (− 40&#xa0;°C), fracture behavior, and pitting corrosion resistance of the weld. The lower region absorbed substantially lower Charpy impact energy (73&#xa0;J) than the upper region (290&#xa0;J) and exhibited greater pitting susceptibility, as reflected by maximum pit sizes of approximately 35&#xa0;μm, 91&#xa0;μm, and 820&#xa0;μm in the top, middle, and bottom regions, respectively. A post-weld heat treatment at 1080&#xa0;°C for 1&#xa0;h homogenized the microstructure throughout the weld thickness by promoting austenite formation, reduced the average ferrite fraction from approximately 71% to 53%, increased the absorbed energy of the lower region to 296&#xa0;J, and enhanced pitting corrosion resistance, thereby substantially improving through-thickness uniformity in microstructure and properties.</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

Process-induced through-thickness microstructural heterogeneity and property gradients in thick-section electron beam–welded UNS S32205 duplex stainless steel

  • 期刊论文

  • 发表日期：

    2026年7月30日

查看全文
  • Jastej Singh,
  • A. S. Shahi

摘要

Achieving through-thickness uniformity in microstructure and properties remains a key challenge in thick-section welds fabricated using high-energy-density joining processes. In this study, detailed microstructural characterization and property evaluations were performed on a full-penetration 18-mm-thick autogenous electron beam weld in UNS S32205 duplex stainless steel. The weld joint exhibited a tapered fusion-zone morphology characteristic of keyhole welds, with the fusion-zone width decreasing from approximately 8 mm in the upper region to 2 mm at the weld root. Pronounced through-thickness microstructural heterogeneity developed in the fusion zone. The upper and middle regions exhibited a more favorable ferrite–austenite balance, whereas the lower region showed significantly suppressed ferrite-to-austenite transformation, resulting in a higher ferrite fraction and increased susceptibility to Cr-nitride precipitation. This phase heterogeneity governed the local low-temperature impact toughness (− 40 °C), fracture behavior, and pitting corrosion resistance of the weld. The lower region absorbed substantially lower Charpy impact energy (73 J) than the upper region (290 J) and exhibited greater pitting susceptibility, as reflected by maximum pit sizes of approximately 35 μm, 91 μm, and 820 μm in the top, middle, and bottom regions, respectively. A post-weld heat treatment at 1080 °C for 1 h homogenized the microstructure throughout the weld thickness by promoting austenite formation, reduced the average ferrite fraction from approximately 71% to 53%, increased the absorbed energy of the lower region to 296 J, and enhanced pitting corrosion resistance, thereby substantially improving through-thickness uniformity in microstructure and properties.