Before and After Comparison of LRO and TV of Rotors After Low Temperature Gas Nitriding and Polymer Coat for Increased Corrosion Life 2000-01-0446

Hayes Lemmerz has published in previous papers (Ref-1, 2 & 3), the method to low temperature nitride and polymer coat cast iron rotors to provide increased corrosion life, wear resistance and reduction in brake noise. We have, in this paper, investigated the two key dimensions of the rotor before and after the Nitriding Process. Low temperature (1050 degrees F) nitride finish machined rotors have to be handled in a special support fixture to prevent a change in thickness variation (TV) and lateral runout (LRO). Hayes Lemmerz has developed methods to keep LRO and TV in the print specification after the Nitriding and polymer coat process. The parts are made to extremely tight LRO and TV tolerances so that Nitriding done on such rotors, the dimensions of the rotors do not exceed print specification.