What are the roles of the chemical elements present in steel?

The role of chemical elements in steel

People often think of steel as pure iron, but in fact, steel is based on iron and combines various elements such as carbon, silicon, manganese, and copper. These elements act like seasonings, enhancing the performance of steel in terms of toughness, strength, corrosion resistance, and Performance. Below, we will introduce the roles of the basic elements: carbon, silicon, manganese, and copper.

• Mechanical Properties

Carbon is the most important alloying element in steel, determining the properties of the steel.

A type of interstitial carbide forms between carbon and iron atoms, which helps prevent deformation of the iron atoms. At the same time, it increases the yield strength, tensile strength, and hardness of the steel.

The higher the carbon content, the more brittle carbides are present in the steel. High-carbon steel is prone to fracture in low-temperature environments, whereas low-carbon steel has high toughness.

• Heat Treatment Properties

The higher the carbon content, the higher the hardness of the steel during quenching, which increases the depth of the hardened layer. If the hardness after quenching is not high, it indicates poor hardenability of low-carbon steel. Medium- and high-carbon steels achieve better hardenability through quenching followed by tempering.

• Processing Performance

The higher the carbon content, the more likely cracks are to occur in the heat-affected zone during welding. Typically, the carbon content of steel that needs to be welded should be ≤20%. A moderate carbon content (0.3%~0.5%) can effectively balance the hardness and plasticity of the steel.

• Corrosion Resistance

The higher the carbon content, the more it increases the Electrical phenomena and chemical phenomena heterogeneity within the steel, accelerating corrosion; low-carbon steel is less prone to rust compared to high-carbon steel.

Carbon element

• Mechanical Properties

When iron atoms incorporate silicon, the resulting solid solution strengthening effect can improve the yield strength and tensile strength of the steel.

• Physical Properties

Silicon forms a protective film on the surface of steel, which can prevent the invasion of oxygen at high temperatures and enhance the steel's oxidation resistance and heat resistance.

• Processing Performance

Silicon content greater than 0.6% increases the risk of cracks forming during the welding of steel. Therefore, the silicon content in steel for welding is usually ≤0.3%.

Silicon

• Core Process

Manganese combines with oxygen in molten steel, which can reduce the oxygen content in the steel, decrease oxide impurities, and improve the purity of the steel.

• Heat Treatment Process

Manganese can effectively improve the hardenability of steel, broaden the quenching temperature range, and reduce the risk of quenching cracks.

• Processing Performance

Adding an appropriate amount of manganese to steel can improve the strength and toughness of the weld metal, so steel is less likely to develop cracks during processing.

 Manganese

Copper can form a protective layer on the surface of steel, preventing oxidation. This effectively controls the intrusion of water and oxygen, reducing the rate at which the steel rusts.

• Mechanical Properties

Copper can integrate well with iron atoms, creating a solid solution effect between the two. This effectively increases the yield strength and tensile strength of the steel without reducing its plasticity and toughness.

• Processing Performance

A small amount of copper can reduce the cold stamping of steel, have little effect on its cold bending performance, and minimize tool wear during the steel manufacturing process.

Copper element