Alloy Steel vs Carbon Steel: The Differences Explained

How is steel produced?

The main raw material for iron smelting is iron ore, the main component of which is Fe2O3, without carbon;

The second raw material for iron making is coke.

During iron making, part of coke is left in molten iron, resulting in carbon in molten iron.

Iron and steel production is made from iron ore into pig iron, and pig iron is used as raw material to make steel;

The process of steel-making is mainly the process of removing carbon, which can not be completely removed.

How the steel been made from iron ore
How the steel been made from iron ore
How the steel been made from iron ore
How the steel been made from iron ore
How the steel been made from iron ore
How the steel been made from iron ore
How the steel been made from iron ore

Steel needs a certain amount of carbon to achieve the best performance.

In order to improve the properties of steel, some alloying elements need to be added on the basis of smelting carbon steel.

Pig iron (cast iron) – 2.0-4.5% C;

Steel (carbon steel) – 0.05-2.0% C;

Wrought iron (pure iron) – C content less than 0.05%;

Iron ore → pig iron → steel.

Therefore, steel is an alloy composed of iron and C (carbon), Si (silicon), Mn (manganese), P (phosphorus), S (sulfur) and a small amount of other elements.

In addition to Fe (iron), the content of C plays a major role in the mechanical properties of steel, so it is collectively referred to as iron carbon alloy. It is the most important and the most important metal material in engineering technology.

What is carbon steel?

Alloy Steel vs Carbon Steel: The Differences Explained 1

Carbon steel refers to iron carbon alloy with carbon content less than 2% and a small amount of silicon, manganese, phosphorus, sulfur and other impurities.

The carbon content of carbon steel used in industry generally does not exceed 1.4%.

This is because when the carbon content exceeds this amount, the steel shows great hardness and brittleness, and it is difficult to process and loses its production and use value.

Carbon steel can be divided into ordinary carbon structural steel and high-quality carbon structural steel according to their quality.

The allowable content of sulfur and phosphorus of high-quality carbon structural steel is lower than that of ordinary carbon steel, so the comprehensive mechanical properties are better than ordinary carbon steel.

According to the carbon content, carbon steel is divided into low carbon steel, medium carbon steel and high carbon steel.

With the increase of carbon content, the hardness of carbon steel increases and the toughness decreases.

  • Low carbon steel — carbon content ≤ 0.25%;
  • Medium carbon steel — carbon content > 0.25% ≤ 0.60%;
  • High carbon steel — carbon content > 0.60%.

What is alloy steel?

Alloy Steel vs Carbon Steel: The Differences Explained 2

In order to improve the properties of steel, on the basis of smelting carbon steel, some alloy elements are added to make alloy steel, such as chromium steel, manganese steel, chromium manganese steel, chromium nickel steel, etc.

Alloy steel, also known as special steel, has some special properties, such as high hardness, high wear resistance, high toughness, corrosion resistance and so on.

Alloying elements often added to steel include Si, W, Mn, Cr, Ni, Mo, V, Ti, etc.

According to the total content of alloy elements, it can be divided into:

  • Low alloy steel — total content of alloy elements ≤ 5%;
  • Medium alloy steel — the total content of alloy elements is 5% ~ 10%;
  • High alloy steel — total content of alloy elements > 10%.

Alloy steel is classified by use:

  • Alloy structural steel: used as engineering components (pipes and supports, etc.); Various mechanical parts (shafts, gears, springs, impellers, etc.).
  • Alloy tool steel: used as measuring tools, molds, tools, etc.
  • Special performance steel: such as stainless steel, heat-resistant steel, etc., with special physical or chemical properties.

What are the differences between carbon steel and alloy steel?

The difference between carbon steel and alloy steel is as follows:

Carbon steel is the main alloy additive in steel.

Alloy steel is used to remove carbon from steel and other metals or materials to improve performance.

Carbon steel is classified according to the amount of carbon content in the steel.

The four main categories are low carbon steel and low carbon steel, medium carbon steel, high carbon steel, and ultra high carbon steel.

0.16-0.29% carbon in carbon steel.

They are the most common forms in steel because they are both at relatively low cost and provide acceptable material properties for many applications.

They are neither brittle nor ductile, but they are ductile.

The surface hardness can be increased by carburizing.

The carbon steel in the alloy steel contains about 0.30-0.59% carbon. They balance ductility and strength, and have good wear resistance.

They are used in forging and large industrial and automotive parts.

0.6-0.99% carbon in carbon steel

They are very strong and are used for springs and high strength steel wires.

Ultra high carbon steel contains about 1-2% carbon.

These steels can be tempered to great hardness and used for special products such as axles.

A carbon content of 1.2% above the steel is usually formed by powder metallurgy.

Steel with a carbon content of more than 2% is considered as cast iron. Alloy steels contain different amounts of metals and materials that specialize in their properties.

Carbon steel is a basic metal widely used in almost every industry in the world, including aerospace, aircraft, automobile, chemical industry and national defense.

Different properties of alloy steel can be applied in many fields, including gears under construction, pipes, supports and infrastructure.

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