Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Application of Acoustic Emission Technique and Friction Welding for Excavator Hose Nipple

굴삭기용 호스 니플의 마찰용접과 음향방출기법의 적용

  • Received : 2013.08.21
  • Accepted : 2013.10.15
  • Published : 2013.10.30
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Abstract

Friction welding is a very useful joining process to weld metals which have axially symmetric cross section. In this paper, the feasibility of industry application was determined by analyzing the mechanical properties of weld region for a specimen of tube-to-tube shape for excavator hose nipple with friction welding, and optimized welding variables were suggested. In order to accomplish this object, friction heating pressure and friction heating time were selected as the major process variables and the experiment was performed in three levels of each parameter. An acoustic emission(AE) technique was applied to evaluate the optimal friction welding conditions nondestructively. AE parameters of accumulative count and event were analyzed in terms of generating trend of AE signals across the full range of friction weld. The typical waveform and frequency spectrum of AE signals which is generated by friction weld were discussed. From this study the optimal welding variables could be suggested as rotating speed of 1300 rpm, friction heating pressure of 15 MPa, and friction heating time of 10 sec. AE event was a useful parameter to estimate the tensile strength of tube-to tube specimen with friction weld.

마찰용접은 축 대칭 단면금속을 용접하는 매우 유용한 결합 과정이다. 본 논문에서는 굴삭기용 호스 니플의 관대관 마찰용접을 시행하여 수송산업 등에 적용 가능성을 제안하고 마찰용접 변수의 기계적 특성을 분석하여 최적화 조건을 결정하고자 하였다. 회전속도, 마찰가열압력 및 가열시간 등 주요 변수를 선정하고 각 매개변수의 세 가지 수준에서 실험을 수행하였다. 한편, 최적의 마찰용접조건을 비파괴적으로 도출하기 위하여 음향방출기법이 적용되었으며 카운터, 이벤트 및 파형과 주파수 스팩트럼 등의 AE 파라미터들을 이용하여 마찰용접시 발생하는 신호를 분석하고자 하였다. 인장시험 결과 최적의 용접 변수는 회전속도 1300 rpm, 마찰가열압력 15 MPa, 마찰가열시간 10초로 나타났으며, 이벤트는 마찰용접된 시험편의 인장강도를 추정하는데 유용한 파라미터가 되었다.

Keywords

References

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