Difference Between Carbon Steel and Stainless Steel

Carbon Steel vs Stainless Steel

Steel is an alloy made out of iron and carbon. The carbon percentage can vary depending on the grade, and mostly it is between 0.2% and 2.1% by weight. Though carbon is the main alloying material for iron some other elements like Tungsten, chromium, manganese can also be used for the purpose. Different types and amounts of alloying element used determine the hardness, ductility and tensile strength of steel. Alloying element is responsible for maintaining the crystal lattice structure of steel by preventing dislocation of iron atoms. Thus, it acts as the hardening agent in steel. The density of steel varies between 7,750 and 8,050 kg/m3, and this is affected by the alloying constituents too. Heat treatment is a process which changes the mechanical properties of steels. This will affect the ductility, hardness and electrical and thermal properties of steel.

There are different types of steel as carbon steel, mild steel, stainless steel, etc. Steel is mainly used for construction purposes. Buildings, stadiums, railway tracks, bridges are few places among many where steel is heavily used. Other than that, they are used in vehicles, ships, planes, machines, etc. Most of the daily used house appliances are also made by steel. Now, most furniture is also being replaced by steel products. When steel is used for these applications, it is important to ensure their durability. One drawback in using steel is its tendency to corrode, and there have been various measures taken to reduce or eliminate corrosion of steel. Stainless steel and galvanized steel are two examples of steel which are capable of fighting corrosion successfully.

Carbon Steel

Carbon steel is used to denote steel with carbon as the main alloying element. In carbon steel, the properties are mainly defined by the amount of carbon it has. For this alloy, the amounts of other alloying elements like chromium, manganese, cobalt, tungsten are not defined.

There are four types of carbon steel. This categorization is based on the carbon content. Mild and low carbon steel contain very low carbon percentages. There are three other types of carbon steel as medium carbon steel, high carbon steel and ultra high carbon steel. In the higher carbon steels, the carbon level varies between 0.30–1.70 % by weight. Medium carbon steel has 0.30–0.59% carbon content, whereas the high steel has 0.6-0.99%. Ultra high carbon steel has 1.0-2.0% of carbon content. They can undergo heat treatment successfully. Therefore, normally these are very strong and hard. However, the ductility can be low.

Stainless Steel

Stainless steel is different from other steel alloys because it doesn’t corrode or rust. Other than this, it has other basic properties of steel, as mentioned above. Stainless steel is different from carbon steel due to the amount of chromium present. It contains minimum 10.5% to 11% chromium amount by mass. So it forms a chromium oxide layer which is inert. This is the reason for non corrosion ability of stainless steel. Therefore, stainless steel is used for many purposes such as in buildings, monuments, automobile, machinery, etc.

Carbon Steel vs Stainless Steel

  • Carbon steel can corrode whereas stainless steel is protected from corrosion.
  • Stainless steel is different from carbon steel due to the amount of chromium present. Stainless steel contains minimum 10.5% to 11% chromium amount by mass.
  • There is an in built chromium oxide layer in stainless steel, which is not present in carbon steel.