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Carbon Steel Properties

Sujata Iyer
What is carbon steel? What is it used for and what are its properties? This post will answer these questions and more.
Steel, as we all know is an alloy. An alloy is the combination of two or more metals to form a completely new metal which generally exhibits the properties of all the metals used in making it. Steel is the most widely used alloy.
Whether it is simple things like cutlery and cookware or heavy machinery, steel can be seen in almost every field. This is mainly because of its strength, durability and other such favorable properties.
Steel, when it contains a high amount of carbon in it, is called carbon steel. Here we will discuss some of the most important carbon steel properties.

Properties of Carbon Steel

Before we get into the actual properties of carbon steel, let us first understand what exactly it is. As mentioned earlier, it is steel which has a high level of carbon content in it. It is often referred to as plain steel. This is because it is the most widely used type of steel.
As per the American Iron and Steel Institute, carbon steel is, "Steel that has properties made up mostly of the element carbon and which relies on the carbon content for structure." Now, let us go into the different properties of this type of steel.
First let us see some information about its mechanical properties. These are true when the temperature is 25°C.
  • Its density is 7.845 (×1000 kg/m3).
  • Its tensile strength is 518.8 Mpa (Mega Pascal) and its yield strength is 353.4 Mpa.
Its physical and structural properties are:

✧ The minimum level of chromium, cobalt, zirconium, vanadium, nickel, molybdenum, tungsten, titanium, etc. when not specified in the alloying of steel along with carbon, gives rise to carbon steel.

✧ The minimum level is not specified because they don't make a major difference in the alloying abilities of the steel.
✧ The percentages of Cu, Si and Mn in the alloy do not change from a standard 0.60, 0.60 and 1.65 respectively.

✧ The higher the content of carbon in the steel, the higher is the tensile strength of the steel.
✧ This steel has the ability to become even stronger when given heat treatment.

✧ Though the strength of the steel may increase, its ductility (the ability to be drawn into wires) reduces when the content of carbon used to alloy it increases.
✧ Also, if subjected to very intense heat treatment, the steel can also lose its ability to be welded. Ductility and weldability are very important properties of carbon steel. These are the properties that reduce with heat treatment. So it should be done in moderation.

✧ There are two categories of carbon steel: mild or low carbon steel and high carbon steel.
✧ Mild steel has carbon content of about 0.15%. Needless to say, it is weaker and not ductile. However, it is very malleable. This means that it can be drawn into sheets easily.
✧ High carbon steel contains carbon in percentages between 0.8 and 2.10, averaging somewhere around 1.5%. It is extremely hard. However, it is also extremely brittle as a result of this hardness. Hence, even though it widely used, it has the highest chances of getting broken down.
✧ Low carbon steel can be used in industries that involve welding. The welding uses that it has is in the steel applications for bars, angles and plates in industries.

✧ Medium carbon steel is used in the manufacture of domestic appliances, car bodies, chips, etc.
✧ High carbon steel is used to manufacture high strength products like knives, blades, cutting tools, etc. This is because high carbon steel can absorb a lot of heat, which makes it extremely hard.
Those were some of the most important properties of carbon steel. It is the most widely used metal in the manufacturing industries and so plays a very important role in our lives.