Graphite Fixturing for Improved Heat Treating In Vacuum Furnacing

For decades successful manufacturers of precision parts used heat-treating fixtures made out of metal alloys that combined for maximum quantity of components while trying to minimize the fixture weight in supporting the components to obtain a minimal amount of part distortion. The downside however, was that these alloys would become distorted and embrittled from long exposure to temperatures, often resulting in the damage and the distortion of the components.  There has been a shift in fixturing using carbon fiber composite materials which offer excellent thermal shock resistance and thermal conductivity.  This high thermal stability allows structures to be manufactured with high mechanical strength.  The complete flatness of this material combined with a low thermal mass affords rapid heat-up and cool-down time, reducing cycle times and providing for longer service life.  This paper discusses the (many) pros and (some) cons of using carbon fiber composite fixturing in the heat treating environment.