Critical high strength steel aircraft components such as landing gear must be heat treated while maintaining tight dimensional tolerances. The severity of the direct oil quenching process normally used for hardening these alloys can lead tounacceptable levels of distortion, particularly in complex components. For complex components, interrupted quenching techniques such as ausbay quenching are often employed to minimize distortion. Past practice for ausbay quenching has usually involved the use of salt baths, but more environmentally friendly heat treating methods are now preferred. While integral oil quench vacuum furnaces eliminate many of the environmental concerns associated with salt bath heat treating, their capabilities forinterrupted quenching tend to be limited. However, advanced vacuum furnace designs can be used to perform ausbay quenching through a combination of computer controlled gas and oil quenching. Case studies are presented to demonstrate the advantages ofthese techniques for control of distortion during heat treating of landing gear components.
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