Generally speaking, steel is called "carbon steel" when the primary alloying component used is carbon and no other element requirements are specified; i.e., chromium, cobalt, nickel. 

Carbon steel can be divided into two categories: high carbon steel and low carbon steel. 

As the name suggests, high carbon steel contains a higher amount of carbon, while low carbon steel contains a lower percentage of carbon. 

Mild steel is a form of mild steel. The main difference between carbon steel and mild steel is that 

carbon steel has a higher carbon content whereas mild steel has a relatively lower carbon content.

What is carbon steel:

Typically, carbon steel contains approximately 0.05-1.70% carbon by weight. Increasing the carbon content in steel gives it extra strength and is considered the most economical way to increase the strength of steel. However, steel also tends to become brittle and less ductile as more carbon is added. Therefore, an appropriate balance of carbon must be added to obtain steel with excellent properties. High carbon steel has a carbon content between 0.3-1.70%, and low carbon steel has a carbon content of 0.05-0.15%. Mild steel is the most commonly used steel today due to its relatively low manufacturing price.

High carbon steel handles heat treatments better than low carbon steel and is therefore useful in many applications. Other elemental impurities can also give steel quite interesting properties; namely sulfur. Some common applications of high carbon steel include: rail steel, prestressed concrete, wire rope, tire reinforcement, knives, saw blades, gears, chains, etc.

What is mild steel:

Mild steel is the lowest carbon type of carbon steel and has a relatively low carbon content. Mild steel can also contain other elements such as manganese, silicon and trace amounts of phosphorus. These additional elements protect the structural integrity of metallic iron by preventing dislocations within the iron crystals. Carbon acts as a hardener, and the percentage of carbon added is proportional to the strength of the steel; the strength of steel generally increases as the amount of carbon added increases.

Mild steel is the most widely used steel, used in 85% of 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 commonly used in the production of wire rod, steel plate and other construction materials.

The difference between carbon steel and low carbon steel:

Definition

Generally speaking, carbon steel has a higher carbon content.

Mild steel has a relatively low carbon content.

Carbon content:

Carbon Steel The weight percentage of carbon ranges from 0.05-1.70%.

The carbon content of mild steel is 0.05-0.25% by weight.

Price:

Carbon steel is more expensive.

Mild steel cheaper

Characteristic:

Carbon steel is stronger than mild steel. It is also brittle and breaks easily compared to mild steel.

Mild steel Due to its softer and weaker properties, it can be easily welded into different shapes.

Heat treatment:

Carbon steel can be successfully heat treated.

Mild steel cannot be successfully heat treated