Why Galvanised Steel sheet(GSS) is better than Mild Steel Sheet (MS)?

Answer 1

Galvanised steel sheets are coated with zinc. Zinc coatings prevent corrosion of the protected metal by forming a barrier, and by acting as a sacrificial anode if this barrier is damaged. When exposed to the atmosphere, zinc reacts with oxygen to form zinc oxide, which further reacts with water molecules in the air to form zinc hydroxide. Finally zinc hyroxide reacts with carbon dioxide in the atmosphere to yield a thin, impermiable, tenacious and quite insoluble dull gray layer of zinc carbonate which adheres extremely well to the underlying zinc, so protecting it from further corrosion, in a way similar to the protection afforded to aluminium and stainless steels by their oxide layers.

Hot dip galvanizing deposits a thick, robust layer that may be more than is necessary for the protection of the underlying metal in some applications. This is the case in automobile bodies, where additional rust proofing paint will be applied. Here, a thinner form of galvanizing is applied by electroplating, called "electro-galvanization".


MS Sheets are not coated and hence do not have additional corrosion protection.

Answer 2

Galvanised steel sheet has been coated in zinc. This protects the steel from rust. Unlike paint or a laminate; zinc is scratch resistant and will not expand or shrink off the metal under unusual temperatures.

If a gap does develop, zinc attracts oxygen ions, and will 'rust' instead of the iron. All Zinc has an oxidised coating which (unlike iron) protects from further oxidisation and has desirable physical qualities.

Mild steel sheet has no such protection.

Answer 3

Galvanized sheet or coil is defined as a carbon steel sheet coated with zinc on both sides. Continuous hot dipping, or electro-galvanizing are the two processes used to produce galvanized sheet and coil. A zinc coating is one of the most effective and economical methods of protecting bare steel from a corroding environment. The zinc not only serves as a barrier between the steel and the environment, it will sacrifice itself to protect the underlying steel sheet. Sacrificial, or galvanic protection occurs when two dissimilar metals are in contact and coupled with water and oxygen. Zinc corrodes preferentially to the iron in steel. This protection prevents corrosion of the steel at areas not covered with zinc. Thus, the spread of corrosion from cut edges, drill holes, etc. is minimized.

Answer 4

Depends on your definition of better an or what the application is.