A Fundamental Study on the Surface Failure Strength of Austempered Ductile Iron (ADI) Gears [Performance of ADI Rollers under Minimal Quantity Lubrication (MQL) Conditions

Abstract

Austempered Ductile Iron (ADI), which has much the same strength and toughness as usual steels, has been developed. ADI has many advantages in physical properties and manufacturing, such as weight reduction, good properties of vibration and noise, low cost in machining and heat treatment of blanks due to near-net-shape casting. Using these advantages, it has been reported that ADI can be sufficiently applied as a medium hardness gear material. In addition, it is important to reduce the amount of the lubricant when many problems, i.e. global environment, resource conservation and cost reduction, etc., are considered. So it is necessary to examine the perfarmance of ADI under oil-free condition or Minimal Quantity Lubrication (MQL) condition. In this paper, the surface failure strength of ADI rollers is investigated using a disk machine which simulates the rolling and sliding action of gears. In particular, the surface failure strength under the MQL conditions is examined in comparison with the steel which has almost the same hardness of ADI. As the results of experiments, the surface failure strength of ADI rollers under MQL conditions is as same as that of SCM 435 rollers under usual lubricated condition.