Carburizing is a heat treatment process that induces carbon into the surface layer of steel components to increase surface hardness and improve wear resistance. The process involves heating the parts in a carbon-rich environment, where carbon diffuses into the steel’s surface, forming a hard, durable outer layer. This treatment enhances the material’s resistance to wear, fatigue, and impact, making it ideal for high-performance applications.
Carburizing is typically performed at high temperatures (around 1650 °F to 1750 °F) and at Atlantic heat treat it is done in a gas source. During the process, the carbon atoms diffuse into the surface of the steel, forming a high-carbon layer. This layer is then diffused into the depth and then hardened through quenching in oil, resulting in a tough, wear-resistant surface with excellent fatigue resistance.
The surface hardness achieved through carburizing ranges from 50 HRC for low alloy steels to over 60-65 HRC for high alloy steels and tool steels. This treatment is especially effective for parts exposed to sliding wear or cyclical stresses, where high surface hardness and durability are required.

Benefits

• Carburizing provides superior wear resistance, particularly for components subjected to sliding, abrasive wear, or high contact stresses.
• The hardened surface improves fatigue resistance, making parts less likely to fail under cyclic loading.
• The depth of the carburized layer can be tailored depending on the requirements, offering versatility for different applications.
• While the surface becomes hard, the core remains relatively soft and tough, allowing parts to absorb impacts without brittle failure. The higher carbon content on the surface creates an expansion in the surface layer that leads to compressive stress. This is very helpful to increase resistance against cyclic loads.
• In gears, high carbon content in surface forms retains austenite that will be transformed to martensite during the work due to the mechanical loads. This causes a small increase in volume of the gears that help to fit gear teeth better and improve mechanical movements.

Carburizing is essential for components that need to withstand high friction, wear, and fatigue under harsh operating conditions. It is commonly used in automotive, aerospace, and industrial applications where both high surface hardness and core toughness are crucial for reliable performance.