Suolapolttonitridöinti

Suolapolttonitridöinti, also known as salt bath nitriding, is a thermochemical surface hardening process used to improve the wear resistance, fatigue strength, and corrosion resistance of steel and other ferrous alloys. It involves heating the component in a molten salt bath containing nitrogen-rich compounds, typically cyanides or cyanates, at temperatures ranging from 500 to 600 degrees Celsius.

During the process, nitrogen atoms diffuse into the surface of the metal, forming a hard, wear-resistant layer called a compound layer, which is primarily composed of iron nitrides. Beneath this compound layer, a diffusion zone is created where nitrogen is dissolved in the metal's matrix, contributing to increased fatigue strength. The depth of both the compound layer and the diffusion zone can be controlled by adjusting the process parameters such as temperature, time, and salt bath composition.

Suolapolttonitridöinti offers several advantages over other surface hardening methods. It is a relatively low-temperature process, which minimizes distortion and dimensional changes in the treated parts, making it suitable for complex geometries and finished components. The process is also efficient and can be applied to a wide range of steel types, including carbon steels, alloy steels, and stainless steels. The resulting nitrided surface exhibits excellent hardness and is resistant to abrasive and adhesive wear. Furthermore, the formation of a passive nitride layer enhances corrosion resistance. Applications for salt bath nitriding are found in various industries, including automotive, aerospace, and tooling.