. . . hard and moderate Material as follows: cast iron (ADI-material) heat treatable steel spring steel roller bearing steel high-alloy steel Carbon steel (specialized for heat treatment of carbon steel parts where there is a risk of distortion). Austempering: Austempering leads to a good combination of hardness and toughness with material based on steel and also cast iron. The austempering consists of an austeniting process (850 – 1050°C) and an following quenching process with a specific transiton temperature. This temperature is dependent on the material in question and the required hardness. The medium used usually is a salt heat transfer with temperatures from 250 - 400°C. The retention time in the heat transfer is depending on the complete structural transformation. There is no tempering treatment following the austempering. Compared to the conventional heat treatment the austempering offers the following advantages: minor distortion good combination of toughness and high degree of hardness high degree of Izod / test toughness improved fatigue strength improved bending process Vacuum-Heattreatment: With regard to the vacuum-heattreatment the austeniting process takes place under vacuum and the following quenching process with gas (p.e. nitrogen). The mild gas quenching process during the vacuum-heattreatment leads to minor distortion. Advantages: minor distortion metallic bright surface © 2004 Roll GmbH & Co KG