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

The Korean Society of Mechanical Engineers (대한기계학회)
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Study on Fatigue Property of Material for Oil Hydraulic Piston Pump

유압 피스톤 펌프 소재의 피로특성 연구

  • Kim, Nam-Seok (Dept. of UR Interdisciplinary Program of Mechanical Engineering Graduate School, Pukyong Nat'l Univ.) ;
  • Nam, Ki-Woo (Div. of Advanced Materials Science and Engineering, Pukyong Seoul Nat'l Univ.) ;
  • Kim, Hyun-Soo (R&D Center, Sam-ho Precision)
  • 김남석 (부경대학교 대학원 기계공학과) ;
  • 남기우 (부경대학교 신소재공학부) ;
  • 김현수 (삼호정밀 기술연구소)
  • Received : 2010.12.10
  • Accepted : 2011.02.24
  • Published : 2011.05.01
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Abstract

Oil hydraulic piston pumps are extensively used worldwide because of their simple design, light weight, and cost effectiveness. However, an oil hydraulic pump is likely to have high leakage, friction, and low energy efficiency after long-term use. In oil hydraulic piston pumps the clearance between the valve block and the piston plays an important role in the volumetric and overall efficiency. We studied the wear property of the SACM645 material used in hydraulic piston pumps via experiments with different heat treatments. We prepared three different specimens. The maximum tensile strengths of the QT and QT-nitration specimens are similar (about 820 MPa), but the strains are significantly different. However, the fatigue characteristic depended on the heat treatment.

본 연구는 유압 피스톤 펌프 재료로 사용되고 있는 SACM645소재를 사용하여 모재, QT(quenching & tempering) 시험편 및 QT 질화시험편의 피로특성을 조사하였다. 피로특성 조사결과는 다음과 같다. QT 질화시험편은 피로한도가 인장강도의 80%로 나타나 아주 높은 값을 나타내었다. 이것은 시험편 표면에 단단한 질화처리를 실시하여 피로균열의 발생을 지연시켰고, 피로균열이 발생하더라고 소재가 단단하여 균열진전속도가 늦었다고 판단된다. 파면 관찰결과 피로균열진전 영역에서는 모두 스트라이에이션이 관찰되었고, 피로균열진전 이외의 영역에서 QT 시험편은 벽개파괴의 양상을, 모재와 Qt 질화시험편은 딤플 파괴의 양상을 나타내었다.

Keywords

References

  1. Kim, H. S., Jung, H. W. and Kim, T. G., 2006, "A Study on Fretting Fatigue Characteristic of Connecting Rod for Automobile," Trans. of the KSME06R604, pp, 29-35.
  2. Kim, N. S., Kim, H. S., Seong, K. Y., Ahn, S. H. and Nam, K. W., 2009, "A Study on Wear Property of Oil Hydraulic Piston Pump Material," J. of the Korean Society for Ocean Engineering, Vol. 23, No. 3, pp. 30-34.
  3. Won, S. J., Lim, B. S., Ha, J. Y. and Nam, K. S., 2003, " A Study on the Fatigue Strength of SACM645 Steel under Various Nitriding Methods and Time," The Korean Society of Automobile Engineers, Vol. 9, No, 1, pp. 216-221.
  4. Hwang, B. W., 2003, "Effects of Surface Hardening and Resudual Stress on the Fatigue Characteristics of Nitrided SACM645 Steel," International Journal of Modern Physics B, Vol. 17, No. 8, PP. 1633-1639. https://doi.org/10.1142/S0217979203019435