2018/11/01 Pressing & Sintering

Comparison of different nitriding processes on PM materials and their effect on properties

To meet the need of improved properties, e.g. resistance against fatigue and wear, a variety of hardening treatments can be chosen on steel components. These improved properties are in fact the result of high hardness, the introduction of residual stresses and, with some diffusion treatment methods, a modified chemistry close to the component surface. To avoid larger changes of form and dimension, the hardening process temperature could be kept low, e.g. in the ferritic area. With this temperature restriction in mind, the nitriding diffusion hardening method is often a suitable alternative to achieve the improved properties in question on  conventionally wrought steel. The presence of porosity in a powder metallugy (PM) component could however affect the result. This paper will discuss how properties are influenced by different nitriding processes, PM material grade and component density.