Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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Solidification Cracking Behavior in Austenitic Stainless Steel Laser Welds (Part 2) -Effects of δ-ferrite Crystallization and Solidification Segregation Behavior on Solidification Cracking Susceptibility-

오스테나이트계 스테인리스강 레이저 용접부의 응고균열 거동 (Part 2) - δ 페라이트 정출 및 응고편석 거동에 따른 응고균열 민감도 변화 -

  • Chun, Eun-Joon (Busan Laser Application Support Center, Korea Institute of Machinery and Materials (KIMM)) ;
  • Lee, Su-Jin (Busan Laser Application Support Center, Korea Institute of Machinery and Materials (KIMM)) ;
  • Suh, Jeong (Busan Laser Application Support Center, Korea Institute of Machinery and Materials (KIMM)) ;
  • Kang, Namhyun (Department of Materials Science and Engineering, Pusan National University) ;
  • Saida, Kazuyoshi (Division of Materials and Manufacturing Science, Osaka University)
  • 천은준 (한국기계연구원 부산레이저기술지원센터) ;
  • 이수진 (한국기계연구원 부산레이저기술지원센터) ;
  • 서정 (한국기계연구원 부산레이저기술지원센터) ;
  • 강남현 (부산대학교 재료공학부) ;
  • Received : 2016.10.08
  • Accepted : 2016.10.05
  • Published : 2016.10.31
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Abstract

A numerical simulation of the solid/liquid coexistence temperature range, using solidification segregation model linked with the Kurz-Giovanola-Trivedi model, explained the mechanism of the BTR shrinkage (with an increase in welding speed) in type 310 stainless steel welds by reduction of the solid/liquid coexistence temperature range of the weld metal due to the inhibited solidification segregation of solute elements and promoted dendrite tip supercooling attributed to rapid solidification of laser beam welding. The reason why the BTR enlarged in type 316 series stainless welds could be clarified by the enhanced solidification segregation of impurity elements (S and P), corresponding to the decrement in ${\delta}-ferrite$ crystallization amount at the solidification completion stage in the laser welds. Furthermore, the greater increase in BTR with type 316-B steel was determined to be due to a larger decrease in ${\delta}-ferrite$ amount during welding solidification than with type 316-A steel. This, in turn, greatly increases the segregation of impurities, which is responsible for the greater temperature range of solid/liquid coexistence when using type 316-B steel.

Keywords

References

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