Fatigue strength of shot peened compacted graphite iron

Author:  R. . Peng, T. Vuoristo, D. Backstrom , M. Ahmad, M. Lundberg, S. Johansson
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.74-79)
Doc ID:  2014053
Year of Publication:  2014
Abstract:  
This paper investigates the influence of shot peening on the fatigue strength of a compacted graphite iron (CGI) in two different surface conditions, namely as cast with casting skin and after machining to remove the casting skin. Four combinations of shot peening intensity level (0.07 and 0.1 mmA) and degree of coverage (80% and 120%) were applied. The results have shown that the shot peening has resulted in an increase in bending fatigue endurance limit of 8% to 23% for the CGI with casting skin and of 9% to 17% for the CGI with a machined surface. For both surface conditions, shot peening with the lower intensity but higher coverage or the higher intensity but lower coverage are more effective than the process using the lower intensity and coverage or the higher intensity and coverage. In total, a 49% increase in bending endurance limit has been achieved by combining machining and shot peening with 0.07 mmA and 120% coverage.