Lämpökaasupinnoitus

Lämpökaasupinnoitus, also known as heat gas nitriding, is a surface hardening process used to enhance the wear resistance, fatigue strength, and corrosion resistance of metallic components. This process involves exposing the workpiece to a controlled atmosphere of hot nitrogenous gases, typically ammonia or a mixture of ammonia and inert gases, at elevated temperatures ranging from approximately 500°C to 550°C (932°F to 1022°F).

During lämpökaasupinnoitus, nitrogen atoms diffuse into the surface layer of the metal, forming hard nitrides such as iron nitrides (Fe4N, Fe2-3N) in steels. This results in a hardened surface layer while maintaining a relatively ductile core, thereby improving the component's overall durability without significant dimensional changes.

The process is primarily applied to ferrous metals, especially alloy steels used in tools, gears, and automotive components. It offers advantages including minimal distortion, environmental friendliness due to the absence of liquid mediums, and precise control over case thickness and hardness.

Lämpökaasupinnoitus is often preferred over traditional carburizing or gas nitriding for its cleaner process, reduced thermal stress, and ability to produce narrower hardened zones. The process duration varies based on the desired case depth but typically ranges from several hours to up to a day.

Overall, lämpökaasupinnoitus is an effective surface treatment for extending the service life of machine parts subjected to wear and harsh operating conditions, combining technical efficiency with environmental sustainability.