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What is the difference between galvanized iron and cast iron?

galvanized iron and cast iron

Iron is a widely used metal in the world. Man for his need has used it since ages. Iron has some special properties than other metals. Due to its uniqueness and wide use, it is divided into two main categories. Galvanized iron and Cast iron, these both comprise a wide use in industry, households, sewage and almost in every basic need.

This article will clearly describe some major differences between galvanized iron and cast iron. Moreover, emphasize how both these type of irons are different from each other and makes them unique from the others. As well as their use in different pipelines and sewage purposes.

Galvanized Iron

Galvanized iron is an iron metal protected by a layer of zinc metal coating. This will prevent galvanized iron from rusting and destroying. Galvanization could be performed in two ways, one is by electrochemical method and the second is by hot dip Galvanizing.


A process called hot-dip galvanization can prepare galvanized iron. In this process, the iron goes through hot molten zinc in which zinc heated up to 860 degreesFahrenheit. After coating with zinc, it is exposed to the atmosphere. After reacting with oxygen it, become zinc oxide. Further, it reacts with carbon present in air to form zinc carbonate. This zinc carbonate forms a dull grey layer over the iron that prevents it from rusting or corrosion.


Due to its uniqueness and long-lasting use, it is widely used. Some prominent uses of galvanized iron are as follows:

  • Due to a variety of forms, it used as galvanized pipes and galvanized iron.
  • Galvanized steel frames used in building houses.
  • Body parts of vehicles constructed from it.
  • The usage in high-tension electrical towers, protective gears,andhighway signs.
  • Extensive use in making route iron gates.
  • In making ornaments for walls, roofs and other stuff like this.
  • In buildings to prevent rusting and corrosion on the walls.

In short, it is the one widely used iron with a number of countless advantages and usage.


Cast Iron

Cast iron is an alloy of iron containing 2 to 4 percent of carbon. Moreover, it contains silicon and manganese along with some amount of impurities like Sulphur and Phosphate. Cast iron comesinformation by iron ores.



Cast iron prepared from pig iron in a blast furnace. During its processing, it can be directly formed from the ore of iron when it is in molten form. The impurities, phosphorus,and Sulphur might burn out from molten iron as well as burns out carbon that must replace. According to requirements, carbon and silicon contents should adjust.

Being a less intensive refining material cast iron was a cheaper engineering material than wrought iron. Although it does not require any kind of refining with hammers and stuff,however, it is inferior and brittle in tensile strength.

Depending on the color, cast iron is categorizedinto two forms that are gray iron and white iron. Gray contains more silicon and it is more machinable than white iron. However, both are brittle as well as malleable iron.


Due to its extensiveness and uniqueness, it I widely used for different things and for different purposes. The cast iron mainly used in:

  • Car gears, automobile
  • Dies
  • Machinery parts
  • Crankshafts
  • Making items for heating purposes like pans and different sort of utensils.
  • For baking purposes
  • In steel molds.

Major differences

Although there are so many differences but the few most important differences are as follows:

  • Galvanizing iron is a process of coating iron to prevent rusting and corrosion whereas, Cast iron is a form of smelting iron formed from pig iron in a furnace.
  • Galvanized iron prevent corrosion in two ways that are by the coating and the zinc,on the other hand, cast iron because of its strength is of two forms; gray cast iron and white cast iron.
  • Galvanized iron pipes are widely used in sewage water pipes and for distribution of water among different regions and areas, on the other side, Cast iron used in household appliances and in making utensils.
  • Galvanized iron pipes are light in weight and easy to handle for transport and other purposes. While Cast iron is used mainly for large purposes.
  • The size of galvanized iron pipes varies from 15 mm to 15 mm. However, cast iron depends on the chemical composition of carbon, which is up to 2-4 percent.


Both these types of pipes have thicker walls compared to other steel and iron pipes. Moreover, their rate of corrosion is almost same to other types of steels and irons. Majority of the pipes supplied with cement lining.


Usually, cast iron has low mechanical strength and can easily corrode in harsh conditions. Older pipes have less flexibility and have no external protection. No proper manufacturing effects. As well as poor elastic behavior and poor records.


This article described completely specifications of both cast iron and galvanized iron. This article showed as well that both these irons are a lot more different from each other and serve perfectly in each respect. Moreover, both have different specifications, uses,and benefits and can widely use for so many different purposes.


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