LEADLESS FREE-CUTTING BRASS CASTING AND METHOD FOR PRODUCING LEADLESS FREE-CUTTING BRASS ARTICLE

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a leadless free-cutting brass casting having machinability close to that of a lead-containing brass casting based material and corrosion resistance and mechanical properties equal to or more excellent than those of the material, further adaptive to working with complicated shape and structure, also safe and free from possibility of air pollution by lead, and free from the occurrence of embrittlement even upon heating, and to provide a method for producing a leadless free-cutting brass article.;SOLUTION: A leadless brass casting stock obtained by continuously casting a copper based alloy comprising, by mass, 85.0 to 89.0% copper (Cu), 4.0 to 6.0% tin (Sn) and 5.0 to 10.0% zinc (Zn), and the balance impurities is subjected to cold forging by rotary swaging at a working ratio of 5 to 30%, and is further annealed at 450 to 700°C for 0.5 to 2.5 hr to produce the leadless free-cutting brass casting having excellent machinability.;COPYRIGHT: (C)2005,JPO&NCIPI