Effect of Heat Input on the Microstructure and Mechanical Properties of Reduced Activation Ferritic/Martensitic Steel Weld Metal

Kyoung-Hwan Kim; Gitae Park; Chan Kyu Kim; Chang-Young Oh; Sangwoo Song; Chang-Hoon Lee; Yongjoon Kang

doi:10.3740/MRSK.2025.35.12.676

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2025 Vol.35, Issue 12 Preview Page

Special Issue KIMS - Research Paper

Effect of Heat Input on the Microstructure and Mechanical Properties of Reduced Activation Ferritic/Martensitic Steel Weld Metal 핵융합로 구조용 저방사화강 용접금속의 미세조직 및 기계적 특성에 미치는 입열량의 영향

27 December 2025. pp. 676-682

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Abstract

In this study, the effect of welding heat input on the microstructure and mechanical properties of reduced-activation ferritic/martensitic steel weld metal was investigated to provide a basis for developing welding technology for this steel, which is considered a structural material for fusion reactor blankets. Autogenous bead-on-plate gas tungsten arc welding was performed with heat inputs of 0.57, 1.38, and 2.32 kJ/mm, and the microstructural evolution and mechanical properties of the weld metal were analyzed. The fraction of residual δ-ferrite in the weld metal varied depending on the welding heat input, which acted as a primary factor contributing to the reduction in weld metal strength, although it remained higher than that of the base metal. In addition, the effect of post-weld heat treatment (PWHT) at 730 °C for 1 h was evaluated. Before PWHT, the weld metal exhibited significantly higher hardness compared with the base metal. However, after PWHT, its hardness was substantially reduced, thereby minimizing the differences in hardness of the weld and the base metal.

Keywords

reduced activation ferritic/martensitic steel

gas tungsten arc welding

weld metal

post-weld heat treatment

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Information

Publisher :Materials Research Society of Korea
Publisher(Ko) :한국재료학회
Journal Title :Korean Journal of Materials Research
Journal Title(Ko) :한국재료학회지
Volume : 35
No :12
Pages :676-682
Received Date : 2025-09-24
Revised Date : 2025-11-04
Accepted Date : 2025-11-10
DOI :https://doi.org/10.3740/MRSK.2025.35.12.676

Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

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