Difference between carbon steel and alloy steel

Steel is an alloy that mostly contains iron. But its properties can be changed to suit specific requirements by adding certain other elements. This explains the differences between alloy steel and carbon steel. As the name indicates, alloy steel has other elements added to it whereas carbon steel is a kind of steel having higher carbon content. There are other differences also that will be talked about in this article.

In Alloy steel, the alloy is a basic constituent. In carbon steel, carbon is a fundamental constituent. Alloy steel is difficult to handle while working. Carbon steel is easy to handle while working. Alloy steel is much expensive due to the ratio of different alloy elements. Carbon steel is less expensive because it consists of only a trace amount of other elements. Alloy steel is mainly referred to as the alloy because it consists of a great number of different alloy elements. Carbon steel can also be referred to as steel because, in this steel, iron is also mixed with other elements.

In alloy steel, something like chromium with a little amount of carbon and iron is added. In carbon steel amount to add in the steel may differ according to the different things. In the case of alloy steel, other elements are added to the mixture to increase its hardness and other properties. In the case of carbon, steel carbon is added to iron to increase its hardness. The element added to the alloy steel is basically depends on the use of steel. Carbon steel is also known as plain steel as it contains only carbon as a main constituent and negligible or lowest amount of other elements.

Alloy steel is commonly called alloy due to the addition of other elements to iron and carbon, these added elements as an alloy may be boron, manganese, silicon, chromium, nickel, etc. According to the carbon concentration, carbon steel is also referred by other names e.g., low carbon steel or cast iron.

Comparison Chart

Alloy Steel	Carbon Steel
A high percentage of other elements are present in alloy steel.	A high percentage of carbon is present in carbon steel.
Corrosion
More resistant	Low resistant
Ductility
High	Low
Melting Point
High	Low
Weldability
High	Low
Contains Only
Iron, carbon and alloy elements	Carbon and iron

Carbon steel is also known as the iron-carbon alloy containing less than 2% carbon WC.
Generally also contain small amounts of silicon, manganese, sulfur, phosphorus and carbon steel, in addition to carbon use can be divided into carbon steel and carbon structural steel, carbon tool steel, and ease of cutting structural steel three categories. Carbon structural steel is divided into building structural steel and machinery manufacturing structural steel two kinds.

According to the carbon steel, carbon content can be divided into low-carbon steel (WC ≤ 0.25%), medium carbon steel (WC0.25% – 0.6%) phosphorus, sulfur content and high-carbon steel (WC> 6%) can be divided into ordinary carbon steel (containing phosphorus, sulfur higher), high-quality carbon steel (containing phosphorus, low sulfur) and high quality steel (phosphorus, sulfur less), generally, the higher carbon content, the higher the hardness, higher strength but lower ductility.

Alloy elements in carbon steel are present in trace amounts. The alloy elements may be sulfur, silicon, etc. Carbon steel is categorized into mainly two different categories; one is high carbon steel, and the other is low carbon steel. If the carbon is present in a high amount in carbon steel, it exhibits the different properties like less flexibility, low melting point, etc. If the carbon is present at about 0.05 percent to 0.25 percent, then the carbon steel is known as mild steel or low carbon steel.

Because of the low amount of carbon, the quantity of iron is high in this type of steel, which causes corrosion when intact with the moist environment. Carbon steel with a high amount of carbon contains about 0.6 percent to 1.0 percent of carbon compound and about 0.9 percent of alloy elements. High carbon content steel is very hard and strong and isn’t easy to work with. It is mainly used to make building material. This type of carbon steel is also used by knife makers. Such type of carbon steel is also used in making wires.

To cut the carbon steel mechanically first, you anneal it properly to make expensive and special tools and gadgets. If the carbon steel contains about 0.9 percent to 2.1 percent carbon, then it makes super hard carbon steel. The carbon steel with lower carbon content is more flexible metal. Mild carbon steel is cheap stuff. High carbon steel is difficult to wet. Low carbon steel is easy to weld, stronger steel, and shows good resistance.

Alloy steel is a type of steel that has presence of certain other elements apart from iron and carbon. Commonly added elements in alloy steel are manganese, silicon, boron, chromium, vanadium and nickel. The quantity of these metals in alloy steel is primarily dependent upon the use of such steel. Normally alloy steel is made to get desired physical characteristics in the steel.

Alloy steels are divided into low alloy steels and high alloy steels. When the percentage of added elements goes past 8 (in terms of weight), the steel is referred to as high alloy steel. In cases where added elements remain below 8% by weight of the steel, it is a low alloy steel. Low alloy steels are more common in the industry. In general, addition of one or more of such elements to steel makes it harder and more durable. Such steel is also resistant to corrosion and tougher than normal steel. To alter the properties of steel, it needs heat treatment when elements are added to it.

To keep the alloy steel weldable, carbon content needs to be reduced. As such carbon content is lowered down to 0.1% to 0.3% and alloying elements are also decreased in proportion. These alloys of steel are known as high strength, low alloy steels. You would be surprised to know that stainless steel is also an alloy steel with a minimum of 10% of chromium by weight.

Alloy steel is also said as a metal alloy comprised of iron, carbon, and a remarkable amount of other alloy elements. The alloy element may be silicon, titanium, copper, etc. These elements are named as alloy elements because these are used to make an alloy. The alloy elements added to the steel to upgrade the properties of the steel. The alloy steel is categorized into two categorize. One is low alloy steel, and the other is high alloy steel. Low alloy steel consists of fewer amounts of alloy elements. However, high alloy steel consists of a large number of alloy elements.

Alloy elements are added to the steel to make it more hard or strong or to improve its durability and resistance. The addition of 100 percent chromium as an alloying element along with the carbon and iron makes the steel more resistant to rust or corrosion. Sometimes alloy steel is also called stainless steel. This steel shows the property of resistance to corrosion; hence it is used to manufacture kitchen utensils. Alloy steel is mainly used in the production of pipes for energy applications and to make other appliances like pots, pans, toasters, etc.

Alloying elements that are added up to the metal exhibits different properties. For instance, during the process of steel making Al, Mn or Si is added to S and P and to dissolve oxygen. Nickel (Ni), Manganese (Mn), Silicon (Si), and Copper (Cu) is added up to increase the strength. Chromium (Cr), Tungsten (W), Molybdenum (Mo), and Vanadium (V) also increase the strength.