Manganese bronzes are a group of high strength copper-based alloys that include manganese as an alloying agent and high levels of zinc. They are characterized by high strength and hardness. This grade provides tensile strength to 110,000 psi and hardness well over 200 BHN. Manganese bronzes are used for trunnion bearings, heavily stressed gears, gearshift forks, impellers, marine propellers, valve stems, worm gears, and worms. It is also used for highly stressed machine parts.