Nitrotec®

what is Nitrotec®?

The Nitrotec® process is used to enhance the surface and strength characteristics of a range of carbon and low alloy steels. Wear resistance, improved fatigue performance and excellent corrosion resistance are among the properties conferred by this modern surface treatment technology. Such improvements in performance can significantly reduce the manufacturing and material cost of components, a fact proved repeatedly by the automotive industry on pressed parts.

Nitrotec® is a worldwide trademarked surface engineering process for the treatment of steels and cast irons carried out in the temperature range of 590 -740°C using a gaseous nitrogen bearing atmosphere.

The treatments develop iron (carbo)nitride surface compound layers between 5 and 50 µm thick, supported by a nitrogen/carbon rich diffusion zone in the substrate.

By choice of treatment temperature, time and nitrogen potential of the atmosphere, the structure, composition and hardness of the compound layer and the sub-surface diffusion zone, are controlled. An innovative oxidation technique combined with specially formulated aqueous quenchant and organic sealant are incorporated depending on the engineering requirements of a specific application.

In common with other low temperature surface treatments, Nitrotec® does not introduce distortion into the part, this means that components can be used and fitted directly after treatment.

The conventional Nitrotec® has a pleasing black appearance and vastly superior corrosion resistance to zinc plating. These low temperature diffusion treatments make low alloy and mild steels up to four times stronger, produce wear resistance equal to hard chromium plating and result in a black finish that has outstanding resistance to corrosion.

An important member of the family of Nitrotec® treatments is NITROTEC®-S, a multi-stage process, where parts are first machined to a final surface finish, Nitrotec® treated, surface polished in a controlled manner, followed by a post oxidizing treatment. This finish gives a dramatic improvement in frictional characteristics and corrosion resistance properties, superior to those obtained when using hard chromium plating techniques.

benefits of Nitrotec®

Toughest in wear resistance

Specific hardness profiles indicate the capability of Nitrotec treated components to resist indentation from point contact surface loading.

Surface hardness

The surface hardness as well as the specific hardness profiles indicate the capability of Nitrotec treated components to resist indentation from point contact surface loading.

Strengthening

When rapidly cooled after Nitrotec treatment, significant strengthening of thin sections, as for example sheet metal, occurs. This results in an increase in both yield strength of the base material and its fatigue strength.

Bearing (tribological) characteristics

Nitrotec combined with an organic sealant retained in the micro porous layer, imparts corrosion resistance superior to that of electro plated components, and comparable to that of medium grades of stainless steels. A combination of Nitrotec finishes with a range of organic sealants give salt corrosion resistance with a minimum of 240 hours.

Surface finish

Nitrotec treatments, that are environmentally friendly and clean, ensure that good surface finishes can be maintained.

Aesthetic finish

Nitrotec treatment produces an aesthetically pleasing black/anthracite surface finish.

Dimensional control

Traditional hardening practices may give rise to distortion and poor dimensional control, because metallurgical phase changes when rapidly quenching from high treatment temperatures. During Nitrotec treatment these changes do not occur, therefore allowing the treatment of close-tolerance precision parts, especially thin section components.

Layer

The layer which is formed during Nitrotec consists of compound zone which is supported by a nitrogen-austenite layer. The oxide, so-called magnetite, is about 1 μm in thickness and can be increased up to 4 μm when applicable. Also, the thickness of the compound layer is variable pending on the material and the application. Underneath the nitrogen-austenite, the so-called diffusion zone is created.

fields of application

The types of components that are treated with Nitrotec® include: Pistons, Ball Studs and Other Mild Steel Components.

Nitrotec® is a replacement for chromium plating. It is more environmentally friendly and delivers heat treatment of steels and alloys very successfully.

Improvements in performance can significantly reduce the manufacturing and material cost of components, a fact proved repeatedly by the automotive industry as they use treated pressed parts.