Transactions of the Korean Society of Automotive Engineers (한국자동차공학회논문집)

The Korean Society of Automotive Engineers (한국자동차공학회)
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A Study on Characteristics of Durability for Plunger of High Speed and Ultra-High Pressure Reciprocating Pump Using High Velocity Oxygen Fuel Spraying

초고속 용사 적용 고속 초고압 왕복동 펌프 플런저의 내구성 특성에 관한 연구

  • Bae, Myung-Whan (Department of Mechanical Engineering for Production, Gyeongsang National University) ;
  • Park, Byoung-Ho (Graduate School, Gyeongsang National University) ;
  • Jung, Hwa (Department of Computer Applied Mechanical, Jinju Campus of Korea Polytechnic College) ;
  • Park, Hui-Seong (Graduate School, Gyeongsang National University)
  • 배명환 (경상대학교 기계설계학과) ;
  • 박병호 (경상대학교 대학원) ;
  • 정화 (한국폴리텍대학 진주캠퍼스 컴퓨터응용기계과) ;
  • 박희성 (경상대학교 대학원)
  • Received : 2013.08.12
  • Accepted : 2014.04.30
  • Published : 2014.07.01
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Abstract

The high velocity oxygen fuel spraying (HVOF) is a kind of surface modification process technology to form the sprayed coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. It is desirable to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesion, however, because a semi-molten powder in a spray process has the low efficiency and become a factor that degrades the mechanical property by the inducement of pore-forming within the coating layer. To improve the wear resistance, corrosion resistance and heat resistance, in this study, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps for oil and water used in ironwork are produced with $420J_2$ and the coating layers of plungers are formed by the powders of WC-Co-Cr and WC-Cr-Ni including the high hardness WC. The surface of these plungers is modified by the super-mirror face grinding machine using variable air pressure developed in this laboratory, and then the characteristics of cross-sectional microstructure, and surface roughness and hardness values between no operation and 100 days-operation are examined and made a comparison. The fine tops and bottoms on surface roughness curve of oil-hydraulic pump plunger sprayed by WC-Cr-Ni are molded more and higher than those of water-hydraulic pump sprayed by WC-Co-Cr because the plunger diameter of oil-hydraulic pump is 0.4 times smaller than that of water-hydraulic pump and the pressure of oil-hydraulic pump exerted on the plunger is operated with the 70 bars higher than that of water-hydraulic pump. As a result, it is found that the values of centerline average surface roughness and maximum height for oil-hydraulic pump plunger are bigger than those of water-hydraulic pump plunger.

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References

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