Al-Cu 계 합금에서 Pb 및 Bi 첨가가 피삭특성에 미치는 영향 = Effect of Pb and Bi Element on the Cutting Characteristics in Al-Cu Alloys

다국어 초록 (Multilingual Abstract)

The machinability of Al alloys can be improved by addition of selected elements such as Pb, Bi, Sn, Cd and In. However, these elements have not only different melting points and densities but also form miscibility gap with Aluminium. This kind of phenomenon induces severe gravity segregation. The aim of this study is to observe the effect of several additives such as Pb, Bi on the machinability of Al-Cu alloys. Pb, Bi particles were finer with increasing of cooling rate and Ar bubbling pressure, and were coarsened with longer holding time after stirring. Due to the coarseness of particles with descending by gravitation, the more addition of Pb and Bi, the particle size becomes coarser. As the contents of additional elements increased, cutting properties were remarkably enhanced such as smaller cutting force and lower bite temperature without degradation of tensile properties. It is also found that the Al alloy is the optimum for free-cutting when 0.4% of Pb and Bi are added to Al-Cu alloys.

목차 (Table of Contents)

• 1. 서론
• 2. 실험방법
• 3. 실험결과 및 고찰
• 냉각속도에 따른 쾌삭원소의 입자양상
• 교반정도에 따른 쾌삭원소의 입자크기 변화
• 쾌삭원소 첨가량에 따른 입자양상
• 쾌삭원소 첨가량에 따른 절삭저항
• 쾌삭원소 첨가에 따른 절삭공구의 온도변화
• 쾌삭원소 첨가량에 따른 칩 양상
• 쾌삭원소 첨가에 따른 기계적 특성
• 4. 결론