Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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PWHT Cracking Susceptibility in the Weld Heat-Affected Zone of Reduced Activation Ferritic/Martensitic Steels

핵융합로 구조용 저방사화강의 용접열영향부 후열처리 균열 감수성

  • Lee, Jinjong (Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science) ;
  • Moon, Joonoh (Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science) ;
  • Lee, Chang-Hoon (Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science) ;
  • Park, Jun-Young (Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science) ;
  • LEE, Tae-Ho (Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science) ;
  • Hong, Hyun-Uk (Department of Material Science and Engineering, Changwon National University) ;
  • Cho, Kyung-Mox (Division of Material Science and Engineering, Pusan National University)
  • 이진종 (한국기계연구원 부설 재료연구소 철강재료연구실) ;
  • 문준오 (한국기계연구원 부설 재료연구소 철강재료연구실) ;
  • 이창훈 (한국기계연구원 부설 재료연구소 철강재료연구실) ;
  • 박준영 (한국기계연구원 부설 재료연구소 철강재료연구실) ;
  • 이태호 (한국기계연구원 부설 재료연구소 철강재료연구실) ;
  • 홍현욱 (창원대학교 신소재공학부) ;
  • 조경목 (부산대학교 재료공학부)
  • Received : 2016.09.26
  • Accepted : 2016.10.17
  • Published : 2016.12.30
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Abstract

Post-Weld Heat Treatment (PWHT) cracking susceptibility in the weld heat-affected zone (HAZ) of reduced activation ferritic-martensitic (RAFM) steels was evaluated through stress-rupture tests. 9Cr-1W based alloys including different C, Ta and Ti content were prepared. The coarse grained heat-affected zone (CGHAZ) samples were simulated with welding condition of 30 kJ/cm heat input. CGHAZ samples consisted of martensite matrix. Stress rupture experiments were carried out using a Gleeble simulator at temperatures of $650-750^{\circ}C$ and at stress levels of 125-550 MPa, corresponding to PWHT condition. The results revealed that PWHT cracking resistance was improved by Ti addition, i.e., Ti contributed to the formation of fine and stable MX precipitates and suppression of coarse M23C6 carbides, resulting in improvement of stress rupture ductility. Meanwhile, rupture strength increased with increasing solute C content.

Keywords

References

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