엔진밸브 시트 표면의 오버레이층 특성에 미치는 용접법의 영향

Effect of the Welding Methods on the Characteristics of Overlaying Seat-surfaces of Engine Valves

  • 이병영 (한밭대학교 신소재공학부) ;
  • 최병길 (한밭대학교 신소재공학부)
  • 발행 : 2002.08.01

초록

An overlaying of the seating surfaces of engine valves by OAW, GTAW or PTA weldings are common practice. The OAW method of a lower torch energy density compared to GTAW and PTA methods produces smoother deposits but the pain size at the vicinity of the interface is increased remarkably up to $30~50{\mu\textrm{m}}$ (that of base metal is about $10\mu\textrm{m}$). It's grain coarsening and the solute dilution are related to the decarburizing during OAW could be minimized by reducing the preheating temperature and by maintaining the carbide precipitates in base metal prior to welding. The formation of columnar structures and carbide precipitation zone in the vicinity of the GTAW welded interface, because of the high heat concentration, causes weakened zone on the valve seat face. The width of the reaction boundary zone is about $50\mu\textrm{m}$ for PTA and GTAW overlaying, and about $150\mu\textrm{m}$ for OAW welding. The smaller width of the reaction boundary zone is the less the solute-dilution rate. Thereby PTA welding may be recommended for overlaying of the seating surfaces.

키워드

참고문헌

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