For the development of modern civilization, steel has played a vital role. Steel is not to be confused with iron. Iron is used as the base metal to produce steel. With the invention of steel, we have overcome the ductility of iron and gained a strong metal to fulfill our need. 

Steel is an alloy of iron, composed of carbon content ranging from 0.03% to 1.075%, and often other elements. It has high tensile strength with low cost, thus becoming a major component for the construction of buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons. It is one of the most familiar materials in the world, with an industry of productions exceeding 1.3 billion tons a year.

Types of Steel

Steel can be classified into 4 types mainly.

1. Carbon Steel
2. Alloy steel
3. Stainless Steel
4. Tool Steel

They are discussed below.

Carbon Steel

Carbon Steel can be divided into three main categories

1. Low carbon steel (known as mild steel)
2. Medium carbon steel
3. High carbon steel.

Alloy Steel

Besides Carbon, alloy steel consists of small amounts of one or more alloying elements such as aluminum, manganese, silicon, nickel, titanium, chromium, copper. This introduces some unique properties that are unavailable in regular carbon steel, such as hardness, hardness retention, and corrosion resistance. Compared to carbon steels, alloy steels are more responsive to heat and mechanical operations.

• Alloy steels are extremely important to industries as they are cheaper, widely accessible, easily processable, and have good mechanical properties. 
• Pipes of alloy steel show excellent performance. They have high scale uses in oil and gas drilling. 
• Alloy steels are also used as parts of machines that are subjected to high pressure. 

Stainless Steel

It is a steel alloy with a minimum of 11.5 wt% chromium content. Although stainless still are not stain proof, they don’t rust or corrode as easily as its other counterparts. Stainless steel has its use in many products, but mostly in home appliances and cooking utensils.

Some other advantages are-

• Reduced delivery time of stainless parts due to the lack of need for a finish. 
• Retains strength and shock resistance even at high temperatures. 
• Hygienic due to the smooth and minimal porous surface.
• Excellent fatigue and impact resistance makes the metal last a long time

Tool Steel

Tool steels are alloys of vanadium, cobalt, tungsten, and molybdenum in various amounts, which makes it highly durable and heat resistant. 

They are named as such as they are used to make metal tools like cutting, pressing, extruding and mold-making tools. Their uniqueness comes from their greater deformation resistance, enhanced hardness, and their ability to be used as a cutting edge even at excessive temperatures. This is why tool steels are a perfect match for the shaping of other materials.