What Does Braided Graphite Packing Mean?
Braided graphite packing refers to a rope-like material that is formed in the shape of a ring around a rod. It is used to control leaks and extrusion resistance present in mechanical equipment operating at high pressures and shaft speeds. The packing is often a contributing factor to galvanic corrosion.
Corrosionpedia Explains Braided Graphite Packing
Braided graphite packing is made from high-purity graphite filaments and foils, and possesses excellent chemical resistance, conductivity and resistance to extreme temperatures and pressures.
However, braided graphite packing can facilitate galvanic corrosion, which occurs between the metal component and the graphite packing. Under electrically conductive conditions, the material closest to the anodic end of the galvanic scale is significantly corroded first. The greater the distance between materials on the galvanic scale, the greater the rate and severity of corrosion that occurs.
For example, in a valve using graphite packing, a galvanic reaction that corrodes the valve may be initiated as soon as any conductive fluid is introduced. This is because graphite is more cathodic than the typical metals used to construct valves.