• 대한기계학회논문집A
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• 제34권6호
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• pp.695-700
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• 2010

가스터빈 날개를 덮고 있는 덮개판(Lock plate)의 재료 물성을 유도초음파를 이용하여 측정을 하였다. Lock plate는 가스터빈 발전소에서 아무 극한 환경에서 작동을 하는 부분 중 하나이다. 초음파 속도와 감쇠계수가 서로 다른 3가지 조건의 열처리상태의 재료 물성을 측정하는데 사용되었다. 일반적인 기계적 파괴 인장실험과 비교했을 때, 인코넬 x-750의 재료특성은 다른 열처리 조건에서 탄성계수와 포아슨비를 활용하여 비파괴적인 방법으로 더 효과적으로 알아냈다. 초음파 속도와 인코넬 x-750의 강도는 서로 비례관계에 있으며, 이러한 재료물성 측정은 여러 산업 분야에서 손상 측정에 활용될 수 있다. 또한 유도초음파 기법을 활용하여 장거리, 광범위한 진단으로 시간과 비용을 절감하는데 도움이 되리라 기대된다.

• 한국압력기기공학회 논문집
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• 제17권2호
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• pp.109-118
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• 2021

In the periodic surveillance material test for the spacer component of fuel channel assembly in CANDU, a microstructural characterization analysis is required in addition to the mechanical property evaluation test. In this study, detailed microstructure analysis and simple mechanical property evaluation of archive spacer parts were conducted to indirectly support the surveillance test and assist in the study of spacer material degradation. We investigated the microstructural characteristics of the spacer garter spring coil through comparative analysis with the plate material. The main microstructure characteristics of the garter spring coil X-750 are represented by the fine grain size distribution, the ordering phase distribution developed inside the matrix, the high dislocation density inside the grains, and the arrangement of coarse carbides. In addition, the yield strength of the garter spring coil X-750 was indirectly evaluated to be approximately 1 GPa. We also established an analytical method to elucidate the microstructural evolution of the radioactive spacer garter spring coil X-750 based on Canadian research experiences. Finally, we confirmed the measurement technique for helium bubble formation through TEM examination on the helium implanted X-750 material.

• 대한기계학회논문집A
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• 제33권4호
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• pp.373-379
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• 2009

Presented in this paper is a new experimental technique to measure material properties of lock plate of gas turbine plants by using ultrasonic guided wave. In comparison with the mechanical destructive testings, material characterization of the Inconel x-750 was nondestructively carried out in a more efficient manner to discriminate the change in elastic moduli and the poisson's ratio attributed to the variation of heat treatment condition. The proposed technique shows a satisfactory feasibility via the comparative experiments with the imported lock plate specimens. It is also expected that the guided wave technique can cover a longer and wider range as a new cost-&-time-saving inspection tool due to the interaction with a greater part of specimen, compared to a conventional local point-by-point scheme.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.167-171
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• 1995

The formation of preferred orientations in cold rolled and recrystallized Inconel 690 sheets was studied by the x-ray texture measurements and TEM observations. The increasing{220} pole intensity in the plane normal at the higher reductions was related to the{110}<112> texture component. The rolling texture of the Inconel 690 was the pure metal type. THe dislocation cells were found in the near{110}<112> oriented grains. The onset of deformation twins in the {112}<111>oriented grains. The onset of deformation twins in the {112}<111> oriented grains. The onset of deformation twins in the {112}<111> oriented grains caused the weakening of {112}<111> and the development of {552}<115> in the rolling texture. The annealing texture of the Inconel 690 sheets was dependent on the annealing temperature. The annealing texture of 750$^{\circ}C$ annealed sheets was similar to the cold rolling texture. The major preferred orientations of the 950$^{\circ}C$ annealed specimens were {112}<110> and {001}<110>. The formation of fine and closely spaced annealing twins in the specimen annealed at 1150$^{\circ}C$ led to the randomization of the annealing texture.