Types of Carbon Steel and Usage

Carbon steel globe valveCarbon steel can usually be devided in four groups based on its carbon content:

  • Low and Mild carbon steel
  • The Medium carbon steel
  • Higher carbon steel
  • The Ultra-high carbon steel

Low and Mild carbon steel
The Mild carbon steel has about 0.16 to 0.29% carbon. Undoubtedly, it is the commonest form of steel because its price is usually low and it provides the material properties which are acceptable under many circumstances.
The low carbon steel has approximately 0.05 to 0.15% carbon, so it is neither ductile nor brittle. It is normally used when huge quantities of steel are required, for instance in the form of structural steel. Mild steel density is around 7.85 g/cm3 (0.284 lb/in3 or 7850 kg/m3) and Young's modulus is 30,000,000 psi or 210,000 MPa.
Mild steel is characterized by a low tensile strength practically speaking, but it is malleable and cheap; surface hardness may be increased with carburization.
Low carbon steel suffers from a yield-point runout as the materials suffer 2 yield points. The first one or the upper yield point is positioned higher than the other and its yield drops significantly after the higher yield point. Should the low carbon steel be only stressed to a point in between the lower and upper yield point, the surface might develop Lüder bands.

Medium carbon steel

It has around 0.30 to 0.59% carbon content. Balancing ductility and strength, medium carbon steel and has fatastic wear resistance; it is used in forging and for large parts like automotive components.

Higher carbon steels

The steels successfully undergo the heat-treatment and have a carbon content rangin between 0.30 and 1.70% on average.
Trace impurities from various other elements could have a big impact on the created steel’s qualityl. Trace amounts particularly of sulfur will make the steel red. Low carbon steel alloy contains has 0.05% sulfur and a melting temperature of around 1538-1426°C. Manganese is usually added to better the of low carbon steel hardenability. The additions make the material a low alloy one by some definitions, and AISI's understanding of carbon steel includes up to 1.65% on average.

High carbon steel
The higher ones have Approximately 0.6 to 0.99% carbon content and very strong, utilised in high-strength wires and springs.

Ultra-high carbon steel
Around 1 and 2% carbon content. Steels which could be tempered for greater hardness. The steels are utilized for special purposes such as non-industrial-purpose knives, punches or axles. Most steels having more than 1.2% carbon are made through powder metallurgy. Take notice that steel having a carbon content over 2.0% is seen as cast iron.