gas nitriding
Gas nitriding can provide a component with improved corrosion resistance as well as high wear and fatigue resistance. Components hardened in this way perform reliably even under the most extreme conditions.
Gas nitriding is a thermochemical process that takes place at relatively low temperatures between 500°C and 600°C . During this process, nitrogen is released from ammonia, penetrates the steel surface, and leads to the formation of a diffusion and compound zone. This immediately hard nitride layer does not require a quenching process.
The parts can also be loaded as bulk material. Surface hardness, nitriding depth, and coating thickness can be controlled through precise process control and material selection.
Since manufacturing-related stresses can have a negative effect during the nitriding process, the components should be stress-relieved beforehand . Due to the low thermal stress and the slow heating and cooling rates, gas nitriding is the hardening process that causes the least distortion. The thickness of the diffusion layer, 0.01 millimeters, can already be taken into account during soft machining. Thus, components can generally be nitrided only after they have been completed. Embrittlement of sharp geometric transitions can be prevented by applying a masking paste.
The surface of the workpiece must not have any surface layers and must not be decarburized or oxidized. It is important to clean the component before treatment to ensure that it is free of oils, greases, and rust.
The achievable surface hardness values depend entirely on the base material and are measured using the Vickers hardness test, since methods such as Rockwell penetrate the nitrided layer. Nitride-forming elements such as aluminum, chromium, cobalt, and molybdenum promote the process. Conversely, existing surface hardening has a negative effect on the formation of the nitrided layer.
KEY FIGURES FOR GAS NITRIDING
Temperature:
up to 600°C
Oven size:
900 x 200 mm
Processing time:
from 12 p.m.
Nitriding hardening depth:
up to 0.8 mm
Max. load capacity*:
2,000 kg
*per batch for standard sizes and treatments
Advantages of Gas Nitriding
No delay
Nitriding is the only hardening process that does not cause any process-related distortion of the component.
Hardening of specific areas
Specific areas of the component can be hardened by covering the other surfaces with a protective paste.
Outstanding component properties
Nitriding produces components with improved corrosion resistance and high wear and fatigue strength, capable of withstanding the most severe loads.
No post-processing
Since no distortion occurs during the hardening process, components can generally be nitrided after they have been manufactured.
Nitrocarburizing and Oxidation
To best meet all of our customers' needs, we offer not only short-term and long-term nitriding but also nitrocarburizing and oxidation.
If the component surface is additionally enriched with carbon during gas nitriding, the process is referred to as nitrocarburizing.
This process, which involves a nitriding depth of 0.1 to 0.5 millimeters , is performed overnight. Your component is usually ready for pickup the following business day.
Nitrocarburizing is primarily used to improve lubricity, wear resistance, and emergency running properties. If further improvement in corrosion resistance and the coefficient of friction is desired, we are happy to perform additional oxidation of your component. In this process, the nitride layer on the surface of the workpiece is converted into an iron oxide layer by adding water or oxygen. By individually adjusting the temperature, duration, and atmosphere, the corrosion resistance of your components against a nitriding layer . The surface of oxidized workpieces is anthracite-colored and has a lower coefficient of friction than nitrided surfaces.
We look forward to hearing from you!
Please use our contact form or contact our sales team directly.
Silvio Stranek
Sales, Technical Consulting / Quotes (Upper Austria, Tyrol, Salzburg, Vorarlberg, Bavaria, South Tyrol)
Email. s.stranek@htr.at
Phone: +43 (0) 664 / 88 92 78 10
Thomas Stadlober
Sales, Technical Consulting / Quotes (Styria, Vienna, Lower Austria, Carinthia, Slovenia)
Email. t.stadlober@htr.at
Phone: +43 (0) 664 / 88 64 15 06
OTHER NITRIDING PROCESSES
Plasma nitriding
In plasma nitriding, the surface layer of a workpiece is enriched with nitrogen in an ionized gas atmosphere. This results in clean component surfaces with significantly improved resistance to abrasion and wear.
Salt bath nitriding
In salt bath nitriding, the parts to be treated are immersed in a nitriding bath to increase their surface hardness and are then oxidized in a quenching bath.
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Your Questions, Answered
We have compiled a list of frequently asked questions to help you better understand our services.
What is gas nitriding?
At the gas nitriding is a thermochemical process in which nitrogen is released from ammonia at temperatures between 500°C and 600°C into the surface of steel components. This creates a hard, wear-resistant nitride layerthat requires no quenching—a hardening without any distortion.
What are the benefits of gas nitriding?
– No warping:Sinceno cooling is required, the component retains its dimensional accuracy completely.
– No post-processing:Fullymachined components can be nitrided immediately.
– Outstanding component properties:Thenitride coating provideshigh wear resistance,corrosion protection, andfatigue resistance—even under the harshest conditions.
– Selective hardening:By applyinga protective paste, specific areas can be specifically excluded from the nitriding process.
How does gas nitriding work, exactly?
The nitrogen from the ammonia reacts with the surface of the workpiece and forms a bonding and diffusion zone. This extremely hard layer forms under relatively low thermal stress. The thickness of the bonding layer starts at approximately 0.01 mm, which means the process can be incorporated even during soft machining. For optimal results, a stress-free component geometry is necessary—therefore, we recommend prior low-stress annealing.
For which materials is gas nitriding suitable?
Gas nitriding is particularly suitable for:
– Nitriding steels
– Alloy steels containing nitriding elementssuch asaluminum, chromium, molybdenum, or cobalt
Materials exhibiting surface hardening, decarburization, or oxidation are unsuitable. Before treatment, the surface mustbefree of oil, grease, and rust.
How is hardness measured?
- The Surface hardness depends on the base material and is determined by the Vickers method . Hardness testing methods such as Rockwell are unsuitable, as they would penetrate the thin nitriding layer.