Evaluation of the Effect of Different Plasma-Nitriding Parameters on the Properties of Low-Alloy Steel

This work is concerned with the surface treatment (ion nitriding) of different plasma-nitriding parameters on the characteristics of DIN 1.8519 low-alloy steel. The samples were nitrided from 500 to 570 degrees C for 540 h using a constant 25% N2-75% H2 gaseous mixture. Lower temperature (500-520 degrees C) favors the formation of compound layers of gamma' and epsilon iron nitrides in the surface layers, whereas a monophase gamma'-Fe4 N layer can be obtained at a higher temperature. The hardness of this layer can be obtained when nitriding is performed at a higher temperature, and the hardness decreases when the temperature increases to 570 degrees C. These results indicate that pulsed plasma nitriding is highly efficient at 550 degrees C and can form thick and hard nitrided layers with satisfactory mechanical properties. The results show the optimized nitriding process at 540 degrees C for 20 h. This process can be an interesting means of enhancing the surface hardness of tool steels to forge dies compared to stamped steels with zinc coating with a reduced coefficient of friction and improving the anti-sticking properties of the tool surface.