In this paper, we mainly introduce the use, types and characteristics of carbon steel SS400, S45C and S50C. The first thing to understand is what kind of material is carbon steel? There are three typical types of carbon steel SS400, S45C and S50C. When it comes to metal materials, the first thing to understand is steel. Here to introduce the definition, types and characteristics of carbon steel.

Characteristics of Carbon Steel

Carbon steel is a kind of steel (steel), not alloy steel (special steel). Before introducing the characteristics of carbon steel, let's take a look at the definition of steel.Steel is an alloy based on iron. Iron in the pure iron state is brittle and rusts easily, and cannot be used as an industrial product. Therefore, carbon "C", manganese, phosphorus, etc. are usually added to iron and used in the form of alloys. "Steel" refers to a substance with a carbon content of approximately 0.02% to 2.14%.

The carbon content of more than 2.1% is called "cast iron", and the carbon content of about 2.1% to 6.67% is called cast iron, and when the carbon content exceeds this range, it will become brittle and cannot be used for industrial purposes. JIS classifies iron with a carbon content of less than 0.02% as "pure iron", steel with a carbon content of 0.02% to 2.14% as "steel" and cast iron with a carbon content of more than 0.02% as "iron". Please note the definitions of "iron" and "cast iron".

The carbon content of iron, its generic name and JIS name are as follows:

According to the use, special steels with various characteristics have been developed, such as steel that is not easy to rust and steel with high heat resistance. The materials in steel other than alloy steel or special steel are called carbon steel. In other words, carbon steel is steel in its original state without special additives and processing. The content of elements other than iron "Fe" and carbon "C" in carbon steel is specified to be below a predetermined value, such as 0.3% or less for chromium and 0.05% or less for titanium. There are many types of carbon steel, according to the carbon content, use, strength, etc. are divided into the following categories.

Carbon steel is divided into low carbon steel, medium carbon steel and high carbon steel according to the carbon content. Carbon content 0.02% ~ 0.25% is called low carbon steel, 0.25% ~ 0.6% is called medium carbon steel, 0.6% ~ 2.14% is called high carbon steel. The more carbon in the steel, the harder it is, and as a steel plate made by cold rolling (deforming the material at low temperatures), low carbon steel is used, while for tools that require hardness, etc., high carbon steel is used.

What is Carbon Steel SS400?

SS400 is an SS material called rolled steel (structural steel) that is used for general structural purposes. SS materials also include SS300, SS490 and SS540, but the most widely used is SS400, structural steels with a tensile strength of 400N/mm2 or above.

Compared with other metal materials, SS400 has the characteristics of low price and easy to obtain. Also has the characteristics of easy welding, cutting and other processing. More in the form of plate circulation, can also be sheet metal processing, laser cutting and so on. But it cannot be quenched. In addition, because it is easy to rust, it is necessary to conduct anti-rust treatment such as electroplating and black dyeing.

Use of SS400

In addition to being used as structural materials such as Bridges and ships, SS400 is also widely used in the construction field for large machinery, vehicles and other mechanical fields. When thinking about what to make with iron or steel, it can be said that SS400 is the first material that comes to mind.

Common surface treatment for SS400

SS400 is prone to rust, so it is often nickel-plated, chromium-plated and other surface treatments. The SS materials we see in life, such as Bridges, are mostly electroplated materials that have been further coated. In places that do not require high corrosion resistance, such as places that do not contact water, materials treated with black oxide (oxide film) are sometimes used. The blackened steel plate laid on the entrance and exit of the construction project and the ground is SS400 which has been treated with black leather.

List of common surface treatments for SS400

• Fe3O4 film (dyed black) : The surface of iron is oxidized with a chemical to cover it with a Fe3O4 film. Prevent corrosion.

• Electrolytic nickel plating: using chemical reduction method for nickel and phosphorus plating. It is carried out with heat treatment to increase surface hardness and improve wear resistance.

• Hard chrome plating: A layer of chrome plating thicker than decorative chrome plating. Improved wear resistance and slippability.

• Trivalent chromate: This is a post-plating treatment method used to improve plating quality. Mainly used for electroplating.

S45C is commonly used with SS400

S45C is a kind of SC material (carbon steel), known as carbon steel for mechanical structure. S45C and SS400 are both very commonly used materials. It is the most popular material known to SC. Therefore, it is relatively cheap, easy to obtain, and used in a variety of places.

Wear resistance, hardness, etc. can be controlled by heat treatment such as quenching, so it is often used in mechanical parts that require durability, such as gears. On the other hand, it is easy to rust, so it needs anti-rust treatment such as oil and paint.

S45C commonly used surface treatment

The surface treatment is selected in the same way as SS400. S45C is carbon steel, so in addition to quenching, tempering, often use normalizing, annealing and other general heat treatment. On the other hand, its hardenability is not as high as that of alloy steel, so it cannot be hardened too deeply. Induction hardening is often used when strong surface durability is required, such as for gears.

Features of the S50C

• S50C, like S45C, is a carbon steel for mechanical construction and is an SC material. The carbon content of S50C is 0.50%, and the higher the brittleness, the higher the material cost is than SS400 and S45C.

• S50C, like S45C, is commonly used for mechanical parts and other materials. However, S50C is also a material with a higher carbon content in SC materials. Not only is the hardness and tensile strength high, but also the wear resistance is higher than S45C, so it is used for parts requiring higher strength.

• The S50C can also be heat treated, but corrosion resistance is poor and rust prevention treatment is required.

• SC materials with more carbon content than S50C are such as S55C. S55C is harder than S50C and has excellent properties such as wear resistance. The distinction between S50C and S50C, in addition to material strength, must also consider the shape of the circulating material.

• The advantages, disadvantages and common surface treatment of S50C are the same as those of S45C and S55C.

Standard sizes for SS400, S45C and S50C