Influence of severe shot peening on high and ultra-high cycle fatigue life of 50CrMo4 steel

Author:  L. Trsko, M. Guagliano, O. Bokuvka, F. Novy, M. Bandini
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.80-85)
Doc ID:  2014054
Year of Publication:  2014
Abstract:  
In this study the effect of severe shot peening to improve fatigue properties of quenched and tempered 50CrMo4 steel, used for manufacturing of car wheel hubs is described. Two sets of specimens were machined and one set was mechanically polished and the second one was severely shot peened with use of 8170 peening medium (steel shots, ø = 425 μm), Almen intensity 15.6A and coverage of 1000 % (marked SSP). Results of crystallite size analysis show a decrease of the crystallite size on the surface from average value of 7 4 ± 3 nm for the NP specimen to 38 ± 4 nm for the SSP specimen. Fatigue tests show a significant increase of the steel's fatigue strength mainly in the ultra-high cycle region.