The difference between carbon steel and alloy steel

Most of us are aware of stainless steel as it is commonly used in the manufacturing of utensils. But ask anybody the difference between alloy steel and carbon steel and the chances are that you will draw a blank. 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.

Carbon steel

Carbon steel is mainly composed of two elements of iron, carbon, and generally do not add a lot of alloy element in steel, sometimes referred to as the carbon steel or carbon steel. Carbon steel in addition to carbon generally contain small amounts of silicon, manganese, sulfur, phosphorus by purpose can be divided into carbon structural steel, carbon tool steel, the carbon steel and structural steel cutting three categories. Carbon structural steel is divided into building structural steel and machine manufacturing steel two kinds, according to carbon content can be divided into low carbon steel (WC 0.25% or less) to carbon steel, medium carbon steel (WC0.25 % – 0.6%) and high carbon steel (WC > 0. 6%), according to the phosphorus, sulfur content can be divided into ordinary carbon steel to carbon steel (high phosphorus, sulfur, high quality carbon steel, low phosphorus, sulfur) and high quality steel (containing phosphorus, sulfur, lower), the higher the carbon content is higher in general carbon steel, hardness, the higher strength, but low plasticity.

Carbon steel with good performance, easy processing, low cost, the most widely used in engineering, the usage is the largest, but the performance of the carbon steel can not meet the requirement of the higher performance in many aspects, mainly displays in:

1, the strength is lower

2, low hardenability

3 low and high temperature strength

4, red hardness difference

5, tempering poor stability

6, can’t meet the requirements of particularity

In order to solve some of the pitfalls of carbon steel, improve the performance of the steel to obtain a better performance than carbon steel, hard, plastic toughness, corrosion resistance, dimensional stability, resistance to friction performance, free cutting, etc., with the purpose of adding some alloying elements in iron carbon alloy, alloy steel are formed. Alloy steel is to point to in addition to containing silicon and manganese as alloying elements in steel or solid elements, also contain other alloying elements such as chromium, nickel, molybdenum, vanadium, titanium, copper, tungsten, aluminum, cobalt, niobium, zirconium and other elements, etc.), some still contain some nonmetallic elements (such as boron, nitrogen, etc.) of the steel. According to the content of alloying elements in steel, and can be divided into low alloy steel, alloy steel and high alloy steel.

Alloy steel

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 vs Carbon Steel

• There are many types of steels such as alloy steel and carbon steel

• As the names signify, alloy steel is the type of steel formed by addition of various other elements in the steel through heat treatment.

• Carbon steel on the other hand is steel that has primarily carbon in it and does not require any minimum percentage of other elements.

• Carbon steel is the type of steel predominantly used in the US

• Stainless steel is a kind of alloy steel

Source: Yaang Pipe Industry Co., Limited (

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