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Assessment of Creep Properties of 9Cr Steel Using Small Punch Creep Testing

소형펀치 크리프 시험을 이용한 9Cr강의 크리프 상수 평가

Yun, Gi-Bong;Park, Tae-Gyu;Sim, Sang-Hun;Jeong, Il-Seok
윤기봉;박태규;심상훈;정일석

  • Published : 2001.09.01

Abstract

Recently small punch creep testing (or miniature disc bend creep test) has received much attention through European collaborative research projects. This method was considered as a substitute for the conventional creep rupture testing by which the residual creep life is measured from the specimen taken out from serviced components of high temperature plants. It would be beneficial if the material creep properties such as power law creep constants as well as the creep rupture life can be measured from the small punch creep test. In this paper a method of assessing creep constants from the small punch creep testing is proposed. Finite element analyses were performed to investigate evolution of stress and strain rate at the weakest locations of the small punch creep specimen. Elastic-plastic-secondary creep analyses were carried out. The estimation equations for creep constants by the small punch creep testing are proposed based on the finite analysis results. Small punch creep tests were also performed with 9Cr steel and the accuracy of the proposed equation was verified by the experimental results.

Keywords

Creep;Time-Dependent Fracture Mechanics;Small Punch Test;Power Law Creep;Miniature Specimen

References

  1. Tettamanti, S. and Crudeli, R., 1998, 'Small Punch Creep Test : A Promising Methodology for High Temperature Plant Components Life Evaluation,' BALTICA VI Plant Maintenance for Managing Life & Performance, Vol. 2, pp. 501-509
  2. Parker, J. D. and Stratford, G. C, 1998, 'The Application of Miniature Disc Testing for the Assessment of Creep Damage in CrMoV Rotor Steel,' BALTICA VI Plant Maintenance for Managing Life & Performance, Vol. 2, pp. 477-488
  3. Ule, B., Sustar, T., Dobes, F. and Milicka, F., 1999, 'Small Punch Test Method Assessment for the Determination of the Residual Creep Life of Service Exposed Components,' Technology, Law and Insurance, Vol. 4. pp. 283-293 https://doi.org/10.1080/135993799349036
  4. Li, W. and Rodgers, B., 1999, 'A Finite Element and Experimental Study of Punch and Bulge Testing,' Key Engineering Materials, Vol. 167-168, pp. 55-63
  5. Brookfield, D. J., Li, W. and Rodgers, B., 1999, 'Material Properties from Small Specimens Using the Punch and Bulge Test,' Journal of Strain Analysis, Vol. 34, No. 6, pp. 423-435 https://doi.org/10.1243/0309324991513867
  6. Dobes, F., Milicka, K., 2000, 'Comparison of Creep Properties of Power Plant Pipe Bends after Long Term Exposure,' 26th MPA-Seminar, pp. 24.1-24.10
  7. 박태규, 윤기봉, 장창희, 2001, '소형펀치 크리프 시험중 측정하는 변수에 대한 연구' (submitted to KSME)
  8. Parker, J. D. and James, J. D., 1993, 'Disc-Bend Creep Deformation Behavior of 1/2Cr1/2Mo1/4V Low Alloy Steel,' Fifth International Conference on Creep and Fracture of Engineering Material and Structures, pp. 651-660
  9. Parker, J. D. and James, J. D., 1994, 'Creep Behavior of Miniature Disc Specimens of Low Alloy Steel,' ASME PVP, Vol. 279 Developments in a Progressing Technology pp. 167-172
  10. UIe, B., Sustar, T., Dobes, F. and Milicka, F., 1997, 'Small Punch Test Method Assessment for the Determination of the Residual Creep Life of Service Exposed Components: Outcomes from an lnterlaboratory Exercise,' Intelligent Software System in Inspection and Life Management of Power and Process Plants, pp. 263-276
  11. 윤기봉, 1992, '고온 사용설비 파손방지 기술 개발,' 과학기술처 보고서, KRISS-92-88-IR
  12. 한상인, 정세희, 윤기봉, 1997, '입계부식법에 의한 사용중인 화력발전소 요소의 잔여수명 평가', 대한기계학회논문집 A, 제21권, 제1호, pp. 22-31
  13. 김효진, 정용근, 박종진, 2000, '발전소 고온부의 수명 평가를 위한 소형 시편용 크리프 시험기의 개발,' 대한기계학회논문집 A, 제24권, 제10호, pp. 2597-2602
  14. 박태규, 윤기봉, 2000, '소형펀치 크리프 시험 에 대한 수치해석 및 설험연구(I),' 대한시셰학회 2000년도 제2회 재료 및 파괴부문 학술대회 논 문집, pp. 178 - 183