On the basis of application, the global galvanized iron market is segmented as housing, industry and others. Industrial application segments are further classified as petroleum, water infrastructure and others.
Every year, millions of tons of steel are produced, which is very used in various applications in various forms. Raw iron is processed to get steel with the desired properties, suitable for special applications. The galvanizing process involves the treatment of iron or steel to form a zinc protective layer over the surface to make it resistant to corrosion. The zinc layer on the steel or iron acts as a sacrificial anode, which protects the iron from rusting even if scratched. Iron or steel pipes are used for sending liquids and sometimes solids in various processes. Pipes mainly require good corrosion resistance because they operate under severe conditions and often carry corrosive liquids. Galvanization is among several conventional methods used for corrosion prevention, thus extending pipe life. Most manufacturers use hot-dip galvanization methods to galvanize pipes. This process involves coating iron and steel with a zinc layer by soaking the metal in a molten zinc bath (about 450 ° C). Whereas, another method, the 'electrogalvanizing' process is used where a very good zinc layer is needed on the surface.
Galvanization protects the underlying iron or steel in the following main ways:
- The zinc layer, when intact, prevents corrosive substances from reaching the underlying steel or iron.
- Zinc protects iron with corrosion first. For better results, chromate applications over zinc are also seen as industrial trends. [Reference?]
- In the event that the underlying metal becomes exposed, protection can continue as long as there is zinc close enough to be electrically combined. After all zinc in the area is directly consumed, local corrosion from the base metal can occur.