Galvanizing has long been recognised as the most sustainable finishing process available, and with the ever-evolving emergence of new technologies, it is increasingly becoming even more-environmentally friendly.
Steel is a vital raw material in many industries across the world, but as a metal, it is highly prone to corrosion. In fact, it’s estimated that worldwide, one tonne of steel turns to rust every 90 seconds, which means that for every two tonnes of new steel produced, one is made simply to rust.
Galvanizing protects steel from corrosion by coating the metal with zinc to prevent it from rusting. Clean steel components are dipped into molten zinc at temperatures of up to 450°C, where a series of zinc-iron alloy layers are formed by a metallurgical reaction between the iron and the zinc. Unlike other finishes, the process of galvanizing results in minimal waste, as any zinc that doesn’t instantly form a coating on the metal remains in the galvanizing bath and is subsequently re-used.
A further benefit of galvanizing is its low whole-life cost. The process only needs to be carried out once, and will result in corrosion protection that can last up to 70 years without the need for any time or resource-intensive maintenance or replacement, thus improving economies of scale and savings in energy. Galvanized products, once constructed or installed, can also be removed, re-galvanized and re-used, as well as being easily recycled with steel scrap in the steel production process.
Ongoing Development continues to achieve more sustainability. One such method is the re-use of ‘waste’ heat from furnaces involved in the galvanizing process, via a system of ducting it through heat exchanger units, which provides heat for both degrease and pre-flux tanks. Low flume fluxes have also been developed which ensure that emission limits are achieved with minimum use of energy-consuming abatement equipment.
With its sustainable qualities, long life-span and cost-efficient whole-life savings, hot dip galvanizing can clearly be considered one of the most environmentally-friendly finishing processes available.