نورد و پوشش دهی سطحی فولاد

ROLLING AND SURFACE COATING OF STEEL

نورد و پوشش دهی سطحی فولاد

ABSTRACT

Steel, an alloy of carbon and iron, is a material which is both inexpensive and has great  mechanical strength. However, it is initially produced as steel slabs which are too thick and  heavy to be used. To convert the steel into useful products it must first be rolled into thin  sheets and coiled onto spools. This steel is more useful, but it is still prone to rusting and will  have its useful lifespan seriously shortened if it is used in a damp environment.  To prevent corrosion, the steel is coated with zinc in a process known as galvanising. Zinc is  found above iron in the electrochemical series, which means that in galvanised steel the zinc  is oxidised instead of the steel itself, thus lengthening the useful lifespan of the steel. Zinc is  chosen for this purpose because it is the least expensive of the metals above iron in the  electrochemical reactivity series and it can satisfactorily be coated on steel. If a suitable  paint coating is applied on the galvanised steel surface, the protection effect can be further  enhanced. The common uses of galvanised sheets and coils are the manufacture of roofing material, steel wall cladding and the steel bodies of home appliances.