Various Sizes of Steel Wire, Double Exposure Pile of iron, metal wire rod or coil for Construction industry. steel wire fence rolls. Steel wire tie rolls for construction and industrial. Coil of iron or steel background. Billets of aluminium in the factory. The Hall–Heroult process produces aluminium with a purity of above 99%. Further purification can be done by the Hoopes process. Original size is 1254 × 836 pixels