Steel grade hardness and surface organization after nitriding
Nitriding has become one of the most well known and commonly used techniques for improving the performance of steel components used in industrial settings. Through the injection of nitrogen atoms into the surface layers of a steel product, the steel can be hardened to provide improved wear and heat resistance, increased fatigue strength and a variety of other beneficial characteristics. The hardening caused by nitriding causes the surface of the steel to form a very hard but thin layer of nitrided steel known as a compound layer.
The hardness of the steel grade after a nitriding process depends on several factors, including the type of steel, the nitriding temperature, the magnitude of potential differences and the nitriding time. Different steel grades also react differently when they are nitrided, which means that steel grades of various levels of hardness can be achieved by changing the nitriding parameters. Generally, higher nitriding temperatures lead to an increase in the hardness of the nitrided steel layer, giving it increased wear and heat resistance, while lower nitriding temperatures tend to result in a softer nitrided layer with improved fatigue strength.
The structure of the surface layers after nitriding depends primarily on the type of steel being nitrided and the parameters of the nitriding process. Generally speaking, the surface layers of nitrided steel consist of three different zones, the compound layer, the diffusion zone and the subsurface layer. The compound layer is a very thin layer of nitrided steel located near the surface of the steel. It is the hardest layer, typically consisting of iron nitride (FeN) particles. The diffusion zone is located between the compound layer and the subsurface layer. It consists of both FeN particles and nitrogen atoms which have diffused into the steel. The subsurface layer is located beneath the compound and the diffusion zone, and it consists of residual nitrogen atoms and deformed grains.
Overall, the hardness of the steel grade after nitriding depends on many factors and can vary greatly depending on the steel grade being nitrided and the parameters of the nitriding process. Nitriding is a very useful technique for improving the performance of steel components, and as such, it is commonly utilized in many industrial settings. However, it is important to be aware of the differences between steel grades, the effects of nitriding parameters, and the structure and composition of the surface layers after nitriding in order to ensure that the most suitable and effective nitriding process is chosen for a given application.
