Verhalten von Plasmanitrierschichten unter Kontaktbeanspruchung

Research output: ThesisDiploma Thesis

Abstract

On many machine components for example gears, rolling bearing or on the wheel rail contact high demands are made concerning load-carrying capacity of rolling contact stress. The work in question examines by means of Rolling Contact experiments (RCF), damage analysis and accompanying Finite Elements calculations the influence and differences of carburized and plasma nitrided layer of load-carrying capacity. For the experiments with point contact the ball on rod test stand (BoR) and the with line contact the two rolling contact test stand (2-RCF) were chosen. Numerous tests at heterogenous most different operating range were carried out. Dependent on the load-carrying capacity in question most different damage mechanisms are activated, which were realized and discussed in an extensive damage analysis. The structured proceedings made it possible to find out the following differences: In point contacts there are plastic deformations as dark etching area (DEA) below the contact zone. In line contacts the abrasive surface wear is in the foreground. The arrangement of carburized and plasma nitrided material at lining contact stress is smaller than 1,0 GPa and shows the carburized material a slightly higher contact fatigue strength at 10 % slip. At 22 % slip the plasma nitrided material shows a little bit higher contact fatigue strength. Because of the bigger slip the friction moment increases, thats why the shear stress maximum moves closer to the surface. The plasma nitrided connection layer is very much harder than the carburized layer, which leads to a bigger local RCF resistance. The tendentious results from rolling contact tests can in comparison be applied to gears according to DIN 3990. A standardized model to the direct transfer of 2-RCF tests on machine components such as gears is not known. In further works experiments on the FZG-test stand should be carried out in order to develop models for direct transfer of local tribologic RCF system stress from disc-shaped replacement geometries on machine components such as gears.

Details

Translated title of the contributionBehaviour of plasma nitrided layer under rolling contact stress
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
Award date14 Mar 2008
Publication statusPublished - 2008