A bronze bolt with a hex head.
Silicon bronze is an alloy made of 95%-98% copper plus a small amount of silicon added for strength. Small amounts of manganese and aluminum may also be added for strength, and lead may be added for machineability. Silicon bronze is non-magnetic with a high degree of thermal and electrical conductivity and high corrosion resistance against sea water, gases, and sewage. It is often used by the utilities industry for pole line hardware and switchgear equipment, mine sweeping, sewage disposal equipment, food machinery, marine applications, plumbing, and liquid handling.