FREE-CUTTING COPPER ALLOY CONTAINING VERY LOW LEAD

The free-cutting copper alloy according to the present invention contains a greatly reduced amount of lead in comparison with conventional free-cutting copper alloys, but provides industrially satisfactory machinability. The free-cutting alloys comprise 71.5 to 78.5 percent, by weight, of copper, 2.0 to 4.5 percent, by weight, of silicon, 0.005 percent up to but less than 0.02, by weight, of lead, and the remaining percent, by weight, of zinc. La aleacion de cobre de corte expedito de acuerdo a la presente invencion contiene una cantidad grandemente reducida de plomo en comparacion con las aleaciones de cobre de corte expedito convencionales, pero proporciona capacidad de maquinado industrialmente satisfactoria. Las aleaciones de corte expedito comprenden 71.5 a 78.5 por ciento en peso de cobre, de 2.0 a 4.5 por ciento en peso de silicio, de 0.005 por ciento en peso hasta pero no menos de 0.02 por ciento en peso de plomo y el por ciento en peso restante de zinc.