Abstract
Components subject to rolling contact fatigue, such as gears and rolling bearings, are among the fundamental machine elements in mechanical and vehicle engineering. Rolling bearings are generally not designed to be fatigue-resistant, as the necessary oversizing is not technically and economically marketable. In order to improve the load-bearing capacity, resource efficiency and application possibilities of rolling bearings and other possible multi-material solid components, a new process chain was developed at Leibniz University Hannover as a part of the Collaborative Research Centre 1153 “Tailored Forming”. Semi-finished products, already joined before the forming process, are used here to allow a further optimisation of joint quality by forming and finishing. In this paper, a plasma-powder-deposition welding process is presented, which enables precise material deposition and control of the welding depth. For this study, bearing washers (serving as rolling bearing raceways) of a cylindrical roller thrust bearing, similar to type 81212 with a multi-layer structure, were manufactured. A previously non-weldable high-performance material, steel AISI 5140, was used as the cladding layer. Depending on the degree of forming, grain-refinement within the welded material was achieved by thermo-mechanical treatment of the joining zone during the forming process. This grain-refinements lead to an improvement of the mechanical properties and thus, to a higher lifetime for washers of an axial cylindrical roller bearing, which were examined as an exemplary component on a fatigue test bench. To evaluate the bearing washers, the results of the bearing tests were compared with industrial bearings and deposition welded axial-bearing washers without subsequent forming. In addition, the bearing washers were analysed micro-tribologically and by scanning acoustic microscopy both after welding and after the forming process. Nano-scratch tests were carried out on the bearing washers to analyse the layer properties. Together with the results of additional microscopic images of the surface and cross-sections, the causes of failure due to fatigue and wear were identified.
Highlights
Introduction and MotivationDepending on operating conditions, some regions of machine components are exposed to higher mechanical, chemical or thermal stresses than others
The first test showed that the tailored forming axial bearing washers have running times of more than 330 h, which is nearly comparable to those of industrial bearings made of AISI 52,100
It can be concluded that the failure is a normal fatigue damage as the depth of the failure is within the range of the max. load induced stresses
Summary
Some regions of machine components are exposed to higher mechanical, chemical or thermal stresses than others. In this context, conventional mono-material components consisting of the multi-material approach offers ample potential for efficient material utilization by applying different same highinstrength withinFor the reducing whole component areenergy not resource efficient.during. By combining individual benefits of several materials in one component, it components service life, lightweightparts and less can be in regions apart from is possible to produce multi-material withexpensive extended material functionality andused specific property profiles the highly stressed zones. The it is possible to produce multi-material parts with extended functionality and specific property profiles developing of new concepts to produce multi-material components has been gaining in importance optimized according to the predominant load collective [1] Motivated by this objective, the developing in recent years. Of new concepts to produce multi-material components has been gaining in importance in recent years
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
