Tadeusz Frączek

Unconventional Glow Discharge Nitriding of 316L Austenitic Steel

This work presents the results of investigations of unconventionally glow-discharge nitrided 316L austenitic steel. The process of nitriding was performed using a variety of variants of sample orientation in glow-discharge chamber. The samples subject to nitriding were located directly on cathode, on the surface isolated from both cathode and anode, in so-called ‘plasma potential’, while the part of the samples with this orientation were additionally covered with screens to supported nitriding process. In order to evaluate the efficiency of various variants of nitriding, the following investigations were conducted: hardness test, element distribution profile within surface layer, metallographic tests, tribological and corrosion resistance tests.

Unconventional Short-term Glow Discharge Nitriding of 316L Austenitic Steel

The AISI 316L grade austenitic steel after glow discharge nitriding at a temperature of T = 598 K and for duration of uf074 = 10,8 ks, for different variants of specimen arrangement in the glow-discharge chamber was investigated. In the first variant specimens were placed on the cathode and in the second variant specimens were positioned also on the cathode, but shielded with a booster screen. In order to assess the effectiveness of nitriding process variants a profile analysis examination of obtained surface layers, surface hardness tests and surface layer hardness profile examination, analysis of surface layer structures and corrosion resistance tests were carried out. It was found that application of a booster screen effects in a nitrogen diffusion depth increment into the 316L austenitic steel, resulting in a surface layer thickness escalation.

Tensor Interpolation of Tribological Wear in Ionitriding of 316L Steel

The research results for polynomial tensor interpolation of tribological wear of austenitic 316L steel are analyzed for the first time in this paper. A tribological study was carried out on the tester T-05, both for samples after the process of glow discharge nitriding and for samples of 316L steel in the initial state [1, 2]. The influence of the nitriding parameters on the weight loss of the samples during the abrasion test and the friction coefficient of the abrasion pair were determined. In this paper the actual results which were obtained so far during the research of tribological wear in an interpolative area were put together with the theoretically determined and experimentally verified real research results for tribological wear in the area beyond the scope of interpolation. It was determined that each of the selected nitriding parameters significantly affects abrasive wear resistance of 316L steel, at the same time, in the nitriding process, as time and temperature increase the resistance to wear abrasion becomes better. The mathematical model for planning of experiments with different glow discharge nitriding processes combined with polynomial interpolation of the obtained research results of many variable functions will enable to choose the nitriding process parameters to obtain the assumed and required property of useful nitrified elements. The developed computer program enables multidimensional interpolation of the research results and is a universal tool which can be used in any research field.