Minimizing Distortion Through 'one Piece Flow - Heat Treatment'

Proper control of distortion has become even more important on new powertrain designs. Distorted gear components can create noise in the transmission, require post heat treat machining processes and may even create problems during transmission assembly. By applying the technology of Low Pressure Carburizing and High Pressure Gas Quenching, the distortion can be significantly reduced. With the introduction of ‘One Piece Flow - heat treatment’, the distortion control can be further enhanced. This ‘One piece Flow – heat treatment’ allows for a rapid case hardening where the components are low pressure carburized at high temperatures (1050°C) followed by gas quenching. The components are not treated in conventional big batches with multiple layers, but in small batches consisting of one layer only. The quench intensity is controlled more precisely to allow for customized processes. The single-layer treatment provides - homogenous and rapid heating of the components, - homogenous and rapid carburizing, - homogenous and precisely controlled gas quenching. All the variations from layer to layer are eliminated, which leads to reductions in distortion-variation within the load. In addition, this new technology allows strong costs-savings for logistics. The manufacturing-line can be completely automated since the parts are 1st taken one by one from the soft machining unit, then 2nd heat treated in time with the cycle-time of soft machining (“Synchronized heat treatment”) and then 3rd passed down one by one to the hard machining unit. The paper presents applications for enhanced distortion control when using ‘One Piece Flow - heat treatment’.