Ferritic nitrocarburising

Ferritic nitrocarburising is a thermochemical surface hardening process that involves diffusion of both nitrogen and carbon into the part. Bodycote’s proprietary process of this low temperature surface treatment, called Lindure^®, involves the addition of oxygen. As a result, there are significant improvements of fatigue properties, adhesive wear resistance and anti-seize properties.

Benefits of ferritic nitrocarburising

The primary objective of ferritic nitrocarburising treatment is to improve the anti-scuffing characteristics of components. The compound layer exhibits significant improvement in adhesive wear resistance. With the introduction of nitrogen in the diffused zone fatigue properties are enhanced. An added benefit of the process is minimal distortion due to short process cycle within the ferrite phase.

Application & materials

Ferritic nitrocarburising is applied to a wide range of engineering components, such as textile gears, rocker arm spacers, cylinder blocks, pumps and jet nozzles, which are treated for wear resistance properties. Crankshafts and drive shafts are treated to enhance fatigue properties.

Common applications include spindles, cams, dies, hydraulic piston rods, and powdered metal components.

Highlights of successful applications:

• Automotive washers
• Races and cones for commercial-grade bearings
• Various types of tooling, including dies
• Lindure^® can be applied on low carbon, low alloy steels, medium and high-carbon steels, tool steels, cast and ductile irons

Ferritic nitrocarburising process details

The process is used to surface harden various carbons, alloy steels, different grades of cast and ductile iron.

The parts are first cleaned to eliminate surface contamination. The process is conducted completely within the ferrite phase, at a temperature usually around 570 °C (1,058 °F) with a process time that ranges from one to four hours. A diffusion layer followed by a compound layer at the surface is formed. The surface layer depth varies from 0.00015 to 0.0015” (0.004 to 0.04mm).