Distortion Control via Optimization of the Cooling Process and Improvement of Quench Oils

Various trials and challenges are underway to increase the cooling power of High Pressure Gas quenching. However, the most important issue is distortion control via the optimization of the cooling process fit for products and should be discussed. Whichever quench media such as molten salt, cold or hot oils and gases, which have quite different cooling characteristics, is selected, the design of the cooling process should be optimized to minimize distortion. Simultaneously, with optimum jig and tray design, various efforts are taken to improve the quench oils based on the world's oldest JIS Quench Oil Evaluation standards. Various quench oils have been developed to reduce distortion problems with joint efforts of suppliers and users. Periodical analysis and control of quench oil characteristics and accumulated improvement of quench oil characteristics (H-value, L.P., viscosity and etc.) enabled the production of quality works. Not only the selection of quench oil types, temperature, agitation and dipping time, but also typical characteristics of cooling processes should be optimized to reduce distortion. In this paper, ideas for a cooling process design will be introduced and several successful examples of distortion control measures are given also for the HPGQ processes. © 2009 Journal of Mechanical Engineering. All rights reserved.