ADI Crankshafts - An Appraisal of Their Production Potential

The paper describes the development of cast iron crankshafts in austempered ductile iron (ADI). A ‘clean sheet’ approach was made covering basic alloy development, fillet rolling and fatigue properties, in order to come up with an alloy with the optimum properties for the application. The effects of variation in the alloying levels, as might be expected in mass production batches, were also studied. Full size crankshafts were manufactured and fatigue information was generated. Finally, ADI crankshafts were fitted into engines where noise and vibration measurements were undertaken followed by engine durability testing. This latter, most important, phase of the project was less successful and some engine failures occurred. These failures are also discussed. The work has highlighted some very worthwhile information on ADI as an engine crankshaft material and the paper indicates areas where of additional work is still required.