The Brasses
70/30 brass also called as cartridge brass contains 70% copper and 30% Zinc. This is employed for cartridge cases, sheet fabrication, and condenser tubes and for usual purposes. Its superior tensile strength varies in between 350 and 600 N/mm2. This is soft and ductile in and annealed form can endure severe cold working.
60/40 brass of Muntz metal contains 60% copper and 40% Zinc. Its UTS varies in between 400 and 850 N/mm2. This is suitable for hot working operations and for casting also. Many marine fittings and cast valves are made out of such brass. Addition of 2% Pb enhances its machin-ability.
A minute addition of Fe, Al, Sn, Mn and Nickel to 60/40 brass enhances its strength considerably. Marine shafts and propellers pump rods, switch gears, autoclaves and high strength fittings are made out of those brasses.
Brazing alloys are in actual the brasses of 50/50 composition along with minute additions of Al, Mn and Sn. These brasses are hard and brittle.