Mechanical Properties of Galvanized Steel

Galvanized steel is a special type of steel that is zinc plated. Galvanization is primarily carried out on the surface of a steel to make it more resistance to corrosion. All galvanized steel has a distinguishing metallic-gray appearance. The surface is also a hundred times smoother than uncoated steel. Because of its high durability, galvanized steel has a wide range of applications from creating steel frames for construction to making automobile parts. For example, truck and bus bodies are made of galvanized steel. It is also used to build up high-tension electronic towers, highway signs, protective gears, and in the manufacturing of metal pails.

Physical Protection

• Galvanized steel is basically a steel substrate that is coated with zinc. Since Zinc has anodic properties against iron, this type of coating prevents the corrosion in the substrate. Galvanization is a primitive chemical process that has been practiced for hundreds of years. Steel is immersed in a molten zinc to produce a coating of zinc-iron alloy. This zinc-iron alloy forms a barrier between the steel and the environment. Zinc is a highly reactive metal in an electrochemical process, and therefore it is easily oxidized to form a coating which protects the steel. Moreover, in galvanized steel, zinc being an active metal, spontaneously reacts with atmospheric oxygen and carbon dioxide to create zinc carbonate which also resists rust formation.

Low Melting Point

• Galvanized steel has better conductivity than uncoated steel and iron. This property of galvanized steel reduces the electrical resistance on the contact area and prevents the steel from overheating when exposed to sunlight or mechanical fiction. Also, Fe-Zn alloy melts at a much lower temperature than zinc. Due to lower melting point, galvanized steel is a suitable candidate for welding where galvanized steel can be closely united by heating and allowing the metals to flow together. Galvanized steel has a higher ductility compared to iron, so the electrical density is highly reduced when pressure is applied from electrode the steel sheets in various metallurgical processes.

Adhesion

• Usually, Galvanized steel sheets are painted before use. This is because paint is quite adhesive to galvanized steel and a painted surface increases the corrosion resistance that galvanized steel already has. Before painting, it is necessary to clean the surface thoroughly. Galvanized steel has a phosphate layer underneath the zinc coating because of ferrous-zinc alloy.

Solderability

• Another important mechanical property of galvanized steel is solderability. One can galvanize the steel sheet without exfoliating the surface film. The film can then be removed by a simple solvent.