EFFECTS OF FORMING PROCESS ON FATIGUE PERFORMANCE OF WHEEL CENTRE DISCS

摘要

This paper considers the effects of sheet metal forming processes on the fatigue performance of automotivernwheel centre discs, manufactured from dual phase steel. Characteristics of the fatigue process for suchrncomponents are crack initiation in a highly strained area, and reflect the forming deformation of the sheetrnand a loading mode that is predominantly bending.rnThis work utilises waisted hour-glass specimens, machined from centre discs taken from each stage of thernmanufacturing process. Attention is paid to the influence of the degree of cold working on fatiguernperformance, with particular emphasis on the interaction between surface hardness and induced residualrnstresses measured on the centre discsrnThe results indicate a correlation between the fatigue-tested wheels and laboratory specimens forrnproducing their respective S-N curves. It can therefore be deduced that the fatigue testing of hourglassrnspecimens machined from the production stages will have a similar relationship if these components couldrnbe fatigue tested under industrial conditions.