C360 Free-Machining Brass Bar Blanks

C360 free-machining brass bar blanks are the benchmark material against which all other copper alloy machinability ratings are measured, achieving the reference rating of 100 on the CDA machinability scale. The alloy composition of approximately 61.5% copper, 35.5% zinc, and 3% lead produces a microstructure where finely dispersed lead particles act as internal lubricants and chip breakers during cutting operations. The machinability advantage of C360 is dramatic and directly translates to lower part costs. Cutting speeds of 300-400 surface feet per minute are routine with high-speed steel tooling, and carbide tooling pushes speeds even higher. The lead particles cause chips to break into small, easily evacuated fragments rather than the long, stringy chips produced by unleaded brass alloys. This clean chip formation allows unattended operation of automatic screw machines and Swiss-type lathes. The 61.5/35.5 copper-zinc ratio places C360 in the alpha-beta brass range, giving it higher strength than the alpha-phase cartridge brass alloys while maintaining adequate corrosion resistance for most indoor and mild outdoor environments. The alloy resists dezincification better than higher-zinc brasses but is not recommended for continuous seawater immersion. C360 cannot be hardened by heat treatment; its mechanical properties are controlled through cold working during the drawing process. The alloy solders and brazes readily but is generally not welded due to the lead content. Our C360 brass bar blanks are available in round, hex, and square cross-sections, cold-drawn from certified domestic mill stock in sizes from 1/4 inch through 1-1/2 inches.