Scholarlink

<p>Residual δ-ferrite in nuclear-grade 316H stainless steel significantly impacts mechanical properties, necessitating strict control of its content. For thick plates, heat treatment alone often fails to meet the required δ-ferrite limits. An alternative strategy by investigating how alloying elements influence the solidification process and residual δ-ferrite formation is explored. Using Thermo-Calc thermodynamic simulations, in situ high-temperature laser confocal scanning microscopy (HT-CLSM), mechanical testing, and microstructural characterization, the effects of alloy composition on δ-ferrite behavior were systematically examined. Results reveal that reducing Cr, Mo, and Si while increasing Ni and Mn markedly decreases residual δ-ferrite content. Composition adjustment lowers the nucleation temperature and raises the solid-state transformation temperature of δ-ferrite, thereby shortening its growth period, promoting peritectic transformation to austenite, and reducing residual δ-ferrite. Fewer δ-ferrite nuclei further enhance this effect. Mechanically, higher δ-ferrite content reduces ductility and toughness due to its lower deformability compared to austenite, yet marginally increasing strength through secondary phase strengthening.</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

Control of residual δ-ferrite content in nuclear-grade 316H stainless steel and its impact on mechanical properties

  • 期刊论文

  • 发表日期：

    2026年5月3日

查看全文
  • Guang-Han Xin,
  • Xin Geng,
  • Xue-Yang Ma,
  • Si-Qi Ren,
  • Zhou-Hua Jiang,
  • Fu-Bin Liu

摘要

Residual δ-ferrite in nuclear-grade 316H stainless steel significantly impacts mechanical properties, necessitating strict control of its content. For thick plates, heat treatment alone often fails to meet the required δ-ferrite limits. An alternative strategy by investigating how alloying elements influence the solidification process and residual δ-ferrite formation is explored. Using Thermo-Calc thermodynamic simulations, in situ high-temperature laser confocal scanning microscopy (HT-CLSM), mechanical testing, and microstructural characterization, the effects of alloy composition on δ-ferrite behavior were systematically examined. Results reveal that reducing Cr, Mo, and Si while increasing Ni and Mn markedly decreases residual δ-ferrite content. Composition adjustment lowers the nucleation temperature and raises the solid-state transformation temperature of δ-ferrite, thereby shortening its growth period, promoting peritectic transformation to austenite, and reducing residual δ-ferrite. Fewer δ-ferrite nuclei further enhance this effect. Mechanically, higher δ-ferrite content reduces ductility and toughness due to its lower deformability compared to austenite, yet marginally increasing strength through secondary phase strengthening.