톱절단법과 연속압입시험법을 이용한 발전소용 배관의 용접 잔류응력 비교평가에 관한 연구

A Study on the Comparative Evaluation of Welding Residual Stresses of Pipes in Power Plants using Saw-rutting and Indentation Methods

  • 발행 : 2003.08.30

초록

최근 발전설비의 용접부에서 발생하는 사고 유형은 용접결함으로 인한 손상은 거의 발생하지 않고 있으나 용접 열영향부와 용접 재질의 물성이 부적절하여 발생하는 것이 대부분이다. 특히 잔류응력은 용접구조물의 파괴에 영향을 주는 것으로 알려져 있다. 그러므로 용접부를 다량으로 포함하는 발전설비에서는 잔류응력의 분포와 크기가 정확하게 파악되어야 한다. 본 연구에서는 발전설비에 사용되는 박판 및 후판의 용접배관의 잔류응력을 파괴적 방법인 톱 절단법과 비파괴적 방법인 연속압입시험법으로 측정한 후 비교하여 측정법의 적절성을 검토하고자 하였다.

It has been widely recognized that the residual stress of the weldment affect the integrity of steel structures and cause an initiation of crack in the welded regions. Since the power plants adopt a variety of welding processes, it is necessary to know the distribution and magnitude of residual stresses. This paper has attempted to investigate the validity of the saw cutting method and the indentation method to measure the residual stresses in the steel plates. The residual stresses in the specimens of hot reheater pipes, cold reheater pipes and feed water lines in power plants were determined by the saw cutting method and the indentation method. The data were compared and reviewed for the validity of the methods.

키워드

참고문헌

  1. R. D. Stout, Weldablilty of Steel, Forth edition, Welding Research Council, pp. 104, (1987)
  2. T. Yamamoto and H, Kayano, 'Nuclear Mater,' Vol. 18, pp. 219-227, (1996)
  3. API RP 579, Recommended Practice for Fitness-for-Service, First Edition, American Petroleum Institute, (2000)
  4. J. Mather, 'Determination of Initial Stresses by Measuring the Deformations Around Drilled Method,' United Engineering Center 345 East 47 Street New York, N.Y. 10017, ASME pp. 249-254, (1936)
  5. W. R. Delameter and T. C. Mauraros, 'Measurement of Residual Streses by hole Driling Method,' Sandia Laboratories Report pp. 77-83, (1985)
  6. F. M. Haggag, R. K. Nanstad and R. Swain, 'Use of Automated Ball Indentation Testing to Measure Flow Propertied Fracture Toughness in Metallic Materials,' ASTM STP 1092, pp. 188-208, (1990)
  7. J. H. Ahn and D. Kwon, 'Derivation of plastic stress-strain relationship form ball indentation,' J. Mater. Res., Vol. 16, pp. 3170-3178, (2001)
  8. W. C. Oliver and G. M. Pharr, 'An Improved Technique for Determination Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments,' J. Mater. Res., Vol. 17, pp. 1564-1583, (1992)