Difference Between Carbon Steel and Mild Steel

Main Difference – Carbon Steel vs Mild Steel

In general, steel is referred to as ‘Carbon Steel’ where the main alloying component used is Carbon and when no other elemental requirement is specified; i.e., Chromium, Cobalt, Nickel. Carbon Steel can be divided into two categories as, high and low Carbon Steel. Just as the names suggests, High carbon steel contains a higher amount of carbon, and low carbon steel contains a low percentage of carbon. Mild Steel is a form of low Carbon Steel. The main difference between Carbon Steel and Mild Steel is that Carbon Steel has a higher amount of carbon whereas Mild Steel has a relatively low amount of carbon.

What is Carbon Steel

Usually, Carbon Steel contains about 0.05-1.70% carbon by weight. Increasing the carbon percentage in steel gives it additional strength and it is also considered as the most economical approach of increasing the strength of steel. However, as a result of adding more carbon, the steel also tends to become brittle and less ductile. Therefore, the right balance of carbon has to be added in order to achieve extra performing steel. High Carbon Steel has a Carbon content between 0.3-1.70%, and Low Carbon Steel has a Carbon content 0.05-0.15%. Low Carbon Steel is the most common type of steel used today due to the relatively low manufacturing price.

High carbon steel can undergo heat treatment better than low carbon steel and hence is very useful in many applications. Other elemental impurities can also bring quite interesting properties to steel; i.e. Sulphur. Some common applications of high steel carbon include; rail steels, pre-stressed concrete, wire rope, tire reinforcement, knives, saw blades, gear wheels, chains, etc.

Main Difference - Carbon Steel vs Mild Steel

What is Mild Steel

Mild steel is the mildest type of carbon steel and has a comparatively low amount of carbon. Mild steel can also have other elements such as manganese, silicon and trace amounts of phosphorous. These additional elements protect the integrity of the structure of metal iron by preventing dislocations within the iron crystals. Carbon acts as a hardening agent, and the percentage of carbon added is directly proportional to the strength of the steel; the strength of steel generally increases with the percentage of carbon added.

Mild steel is the most widespread form of steel and is used in 85% of all steel products in the United States alone. It has become a popular form of iron due to its desirable properties such as ductility, strength and economical price. Mild steel is often used to produce wires, steel sheets and other building material.

Difference Between Carbon Steel and Mild Steel

Difference Between Carbon Steel and Mild Steel


In general, Carbon Steel has a higher amount of carbon.

Mild Steel has a relatively low amount of carbon.

Carbon Content

Carbon steel can have weight percentages of carbon ranging from 0.05-1.70%.

Mild Steel has a carbon content of 0.05-0.25% by weight.


Carbon Steel is more expensive.

Mild Steel is cheaper


Carbon Steel is stronger than Mild Steel. It is also brittle and can break easily when compared to Mild Steel.

Mild Steel can be easily welded into different shapes due to its softer and weaker properties.

Heat Treatment

Carbon Steel can successfully undergo heat treatments.

Mild Steel cannot successfully undergo heat treatments.

Difference between Carbon Steel and Mild Steel - infographic

Image Courtesy:

“Stratford Station roof support” by Goodwin Steel Castings (CC BY-SA 2.0) via Flickr

“Coif” by Drake (CC BY-SA 2.0) via Flickr

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