Effect of Oil Condition On Pinion Gear Distortion

As quench oil ages through use, its cooling power changes.  Effectively, this means its viscosity changes, its vaporization behaviour and thus its heat transfer characteristics.  This paper reports the effect of new, mildly used and over-used quench oil on the distortion of a carburized 8620 steel pinion gear.  The quenching characteristics for these three oil conditions, as measured by a standard quench probe, are used as the base heat transfer data sets.  The local heat transfer coefficients applied to the part surface are modified according to the local velocity field as computed by a CFD model of the base oil.  The predictive software DANTE is used to compute the dimensional change, residual stress state and phase distribution for the three cases, and comparisons will be presented.