A REVIEW OF THE MACHINABILITY OF COPPER-BASE ALLOYS

Machining is widely used as the final shaping operation, and contribut es significantly to the cost, of a manufactured product. As a result, it has been of paramount importance to develop easily ''machinable'' a lloys with minimal sacrifice of other properties, to reduce the associ ated fabrication costs. Until now, leaded brasses have been the indust ry standard for ''free-machining'' copper-base alloys. However, health concerns about the use of lead in alloys, especially in plumbing appl ications, will restrict their use. This has created a need for an alte rnative free-machining copper-based alloy, without lead. MTL/CANMET ha s been involved in establishing such an alloy. The project was partial ly funded by the International Copper Association (ICA), and this revi ew was undertaken to assist this effort to understand and summarize th e data and concepts of the metal cutting process, assessment of machin ability, and the metallurgical factors that contribute to an alloy's m achinability, from the standpoint of copper-base alloys.