Aalberts Surface Technologies (Heat) is part of Aalberts N.V. a global engineering company providing mission critical technologies from more than 150 locations in 30 countries.
The home of hard surfaces
Use Gas Nitriding for great results

Gears before Gas Nitriding

The original Gas Nitride treatment is a “low temperature” furnace treatment with an atmosphere of Ammonia. The Nitriding process is an established and successful means of generating a hard case on a component.

This process is most useful for components such as Crankshafts, Gears and a multitude of other parts in tough environments (especially oil & gas, energy, aerospace, etc).

There are a huge variety of materials that this process can be applied to. In the following table are presented typical hardness and case depth for common nitrided steels:


Surface Hardness Hv

Case Depth mm

EN3A, 070M20, 080M40, Mild Steels

350 - 500

0.100 – 1.00

EN19, 708M40, 4140, 4340, P20

550 – 850

0.025 – 1.00

EN40, 722M24, 31CrMoV9

750 – 1000

0.025 – 0.70

EN41, 905M39, Nitralloy

750 – 1100

0.025 – 0.70

H13, H11, D2, Hot Work Tool Steel

800 - 1200

0.025 – 0.50

The crucial benefits of the process are:
  • Wear resistance: created by a diffused hard surface layer.
  • Negligible dimensional changes.
  • Improved fatigue properties: the process induces compressive stress, which improves fatigue strength.
  • Improved corrosion.
  • No reduction in the core hardness of the base metal.
  • Completed on near finished components requiring minimal (or zero) lapping, polishing or grinding operations following the process the “white layer” produced by the process can be controlled and can be applied to 'local' areas of any geometry.

The characteristics of the process are:
  • Low temperature: 475° C to 550° C.
  • Flexibly applied – process duration modified according to the specification of the required final component properties.
  • Environmentally friendly compared to serious alternatives (e.g. chrome plating).
  • Clean for the component – e.g. leaving no heavy surface contaminant or residue.

Lab Metallography - polishing and grinding for inspection

Nitriding from specialist metallurgists

With a wide variety of furnaces available, we are capable of handling a comprehensive range of product and batch size, from small series through to 10 Tonnes in weight, and sizes up to 4.2m long and up to 1.6m diameter.
Our staff are expert in advising the characteristics achievable from all material types, from low alloy steels to high quality grade stainless steels and Inconel alloys.