Gas Nitriding Behaviour of 34CrAlNi7 Nitriding Steel

Abstract

In this study, gas nitriding behavior of 34CrAlNi7 10 steel was investigated. Single stage processes were carried out at 500 ◦C, 520 ◦C and 540 ◦C for 10, 20, 30 h, respectively. Nitrogen activity on surface was controlled by the nitriding potential KN which is known as thermodynamical control parameter for controlled gas nitriding process. The presence of nitrides formed on surface of test material was determined by X-ray di raction analysis technique. The morphology of nitrided layer was studied by optical microscope. The microhardness of surface of nitrided sample in HV1 was observed between 975 and 1132. Choosing the right nitriding potentials for each temperature, which give the same nitrogen concentration and activity on surface by using the Lehrer diagram, showed that all the samples had almost the same surface roughness of Ra = 0.28 0.32 μm after gas nitriding cycles. The measurements showed that the white layer thickness varies between 4.38 μm and 28.80 μm and the growth of the layer was strongly a ected by process time and temperature. Di usion depths as Nht (HV) for each experiment were determined and compared.