Study of the effects of austempering temperature and time on scuffing behavior of austempered Ni-Mo-Cu ductile iron

Scuffing can occur in various engineering components, including engine cylinders and liners, camshafts, crankshafts, and gears. Austempered ductile iron (ADI) is finding increasing application in these components due to its self-lubricating characteristics and excellent mechanical properties. The objective of this research is to study the scuffing behavior of an austempered ductile iron material austempered at different temperatures and for varying periods of time. Rotational ball-on-disk tests were run with white mineral oil as the lubricant at two sliding speeds. A step load was applied until scuffing occurred. The scuffed specimens were studied using optical and scanning electron microscopy to determine their scuffing mechanisms. Improved scuffing resistance, as evidenced by a higher scuffing load, is related to a decreased hardness and higher level of retained austenite which produce a more ductile material. (C) 2012 Elsevier B.V. All rights reserved.