Einfluss der Probengröße und der Festwalzparameter auf die Schwingfestigkeit bauteilähnlicher Proben

FKM 1997
Booklet No. 223
Project No. 193

Abstract:

The two research projects were concerned with the experimental and theoretical analysis and optimization of the deep rolling finishing process, which is used to increase the fatigue strength of metallic components. Approximately 1,300 set-off round samples made of heat-treated steel 42 CrMo 4, spheroidal graphite cast iron GGG-60 and AFP steel 38 MnVS 5 with diameters ranging from 8 to 64 mm were deep rolled in very different ways and vibration tested under rotating bending and alternating torsion in order to determine the influence of the process parameters on the fatigue strength. In addition to the deep rolling force as the most important parameter, the angle of attack of the rolling roll, the positioning of the rolling roll in the notch and the clearance angle between the rolling roll and the notch also have an influence. Optimized deep rolling increased the fatigue strength of 16 mm notch samples by up to 220 % and the torsional fatigue strength by up to 110 %. The fatigue strength of optimized deep-rolled notch specimens decreases more with increasing part size than that of unstrengthened specimens with the same qualitative asymptotic dependence. All experimental results are available on personal computers in the newly created FRISCO information system. Using non-linear finite element methods, the deep rolling of heel notches and a crankshaft pin bearing was simulated for the first time in order to calculate the residual stress field in the notch base, which is decisive for the fatigue behaviour of deep rolled parts, and to be able to derive correlations between residual stress distribution and fatigue strength for process optimization. Scope of report:
117 pages, 65 images, 13 tables, 51 references Start of work:
No. 167: 01.01.1992 and No. 193: 01.07.1994 End of work:
No.167: 31.12.1993 resp. No.193: 30.06.1996 Funding body:
BMWi I AIF-Nr. 8910 resp. 10036 Research center:
Institute for Materials Science, Technische Hochschule Darmstadt, Head:
Prof. Dr.-lng. C. Berger Editor and author:
Dr.-lng. U. Jung Chairman of the working group:
Dr.-lng. B. Fuchsbauer Audi AG, Ingolstadt Chairman of the Advisory Board:
Prof. Dr.-lng. H. Kipphan Heidelberger Druckmaschinen AG