These elements, which are very good nitride formers, give it a very high surface hardness with good wear resistance after nitriding . From a chemical point of view, the term nitriding steel is incorrect, as this term refers to a very similar sounding, but chemically different process, nitriding .
Due to the thermal stability of nitrides it is up to 400 ° C resistant to tempering .
Use of nitriding steels
Nitriding steels are used wherever very hard and wear-resistant steels are required due to extreme loads. The core is also extremely tough. In addition, the nitrided layers have a low coefficient of friction and increased corrosion resistance.
The scope of application is carefully checked in practice, as the production of nitriding steels is very expensive due to the many processing stages.
Typical nitriding steels
|No. (DIN EN 10027 - replacement for DIN 17007)||designation||Carbon content||Alloy components|
|1.8515||31CrMo12||0.28-0.35%||2.8-3.3% chromium (Cr), 0.3-0.5% molybdenum (Mo)|
|1.8519||31CrMoV9||0.26-0.34%||2.3–2.7% chromium (Cr), 0.15–0.25% molybdenum (Mo), 0.1–0.2% vanadium (V)|
|1.8507||34CrAlMo5||0.30-0.37%||1.0–1.3% chromium (Cr), 0.8–1.2% aluminum (Al), 0.15–0.25% molybdenum (Mo)|
See machinability of steel .