Carburizing is the process of introducing carbon atoms into the surface layer of steel, enabling low-carbon steel workpieces to have a high-carbon surface layer. Following this, quenching and low-temperature tempering are performed, resulting in a surface layer with high hardness and wear resistance, while the central part of the workpiece retains the toughness and plasticity of low-carbon steel.
The materials used for carburizing are generally low-carbon steel or low-carbon alloy steel (with a carbon content of less than 0.25%). After carburizing, the chemical composition of the steel surface can approach that of high-carbon steel. Additionally, the workpiece must undergo quenching to achieve high surface hardness, high wear resistance, and fatigue strength while maintaining the toughness of the low-carbon steel in the core, allowing the workpiece to withstand impact loads.
The main principle is to allow the steel surface layer to endure various loads (wear, fatigue, mechanical loads, and chemical corrosion) in the areas most exposed to these stresses. By infusing carbon and other elements, high surface hardness, wear resistance, fatigue strength, and corrosion resistance can be achieved without the need for expensive alloying or other complex processing methods throughout the entire material. This not only allows for the replacement of certain expensive high-alloy steels with inexpensive carbon or alloy steels but also preserves the toughness of the low-carbon steel in the core, enabling the workpiece to withstand impact loads.