Machinability Evaluation of Leaded and Unleaded Brasses: A Contribution Towards the Specification of Ecological Alloys

Abstract

Trends on materials development are reflecting the need for new specifications of materials composition considering the environmentally related behaviour of both, the manufacturing processes and material/product performance, disposal and recycling during the life cycle of the product. In particular, cast cooper — zinc — lead alloys, used in components for potable water systems and containing a significant level of lead are natural candidates to a reengineering process. The addition of lead is considered to be a key factor in order to improve the machinability of the alloys used in components machined in large batches. It was showed that contamination of potable water with lead occurs in these systems. The contamination of potable water with lead has a deleterious effect on the nervous system, mainly during the early stages of human development. Consequently, new and more stringent standards, governmental and community directives (EEC directive 80/778), together with the pressure of consumers, are pressing the development of alloys with a reduced lead contents or even lead-free copper alloys. Reducing the contents of lead decreases the machinability of brasses. This paper presents the results of a research project aiming the establishment of the minimum lead content of a copper alloy that can be used for watermeter body manufacturing, together with the machinability reference data for ecological copper alloys development.Key WordsMachinabilityCopper AlloysUnleaded BrassChip FormsCutting Forces