Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Inconel 718 and UNSM Treated Alloy Study on the Rotary Bending High Temperature Fatigue Characteristics under a Light Concentrating System

인코넬 718강의 UNSM처리재의 고온하의 피로특성에 관한 연구

  • 서창민 (경북대학교 기계공학부, 대구기계부품연구원) ;
  • 남승훈 (한국표준과학연구원) ;
  • 우영한 (경북하이브리드부품연구원) ;
  • 허광호 (경북하이브리드부품연구원) ;
  • 홍상휘 (경북하이브리드부품연구원) ;
  • 김준형 (선문대학교 기계공학부) ;
  • 편영식 (선문대학교 기계공학부)
  • Received : 2016.06.12
  • Accepted : 2016.08.12
  • Published : 2016.11.01
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Abstract

This study investigated the influence of high temperature and UNSM on the fatigue behavior of Inconel 718 alloy at RT, 300, 500, and $600^{\circ}C$. Fatigue properties of Inconel 718 were reduced at high temperatures compared to those at room temperature. However, the endurance limit was similar to that of the room temperature sample at the design stress level. High-temperature fatigue characteristics of the UNSM-treated specimen were significantly improved at the design stress level as compared to the untreated specimens. Specifically, the influence of temperature on the S-N curves at the design stress level of the UNSM-treated specimen showed the tendency of longer fatigue lives than those of untreated ones. Researchers can obtain rotary fatigue test results simply by heating specimens with a halogen lamp to precise temperatures during specific operations.

고온기기의 부재로 널리 사용되는 인코넬 718을 사용하여 UNSM 표면처리법에 의한 처리효과를 기기의 사용조건을 고려한 실온, $300^{\circ}C$, $500^{\circ}C$ 및 $600^{\circ}C$ 의 세 가지 온도레벨하의 대기 중에서 고온피로 시험을 실시하여 각 시험편의 온도에 따른 피로특성을 연구하였다. 이때 고온회전굽힘피로시험(R=-1)은 할로겐(Halogen) 램프를 사용한 집광식인 가열방식을 선택한 새로운 피로시험기를 사용하였다. 인코넬 718의 고온피로강도는 상온에 비하여 감소하였다. 그러나 설계응력레벨에서는 상온의 내구한도와 유사한 경향을 나타내었다. UNSM 처리된 고온피로특성은 미처리재에 비하여 설계응력레벨에서 크게 향상되었다. 미처리재의 $300^{\circ}C$와 $500^{\circ}C$ 사이의 온도 영향은 거의 없었지만, $600^{\circ}C$에서는 높은 응력레벨에서 피로수명이 짧아졌지만, 낮은 설계응력레벨에서는 상온의 S-N선도보다 피로수명이 증가되는 경향을 나타내었다.

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References

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