When parts are brazed in a vacuum furnace, distortion of those brazed assemblies can easily happen. To prevent parts from distorting, people have tried a variety of things, including extended stress-relieving of components prior to assembling those parts for brazing, the use of rigid fixturing to try to keep parts from moving during a brazing cycle, and even making components heavier and more massive in order to make them more distortion-resistant. Distortion still occurs.
Yes, some of these things, such as stress-relief heat-treatment prior to brazing might help to some extent, but it is not the answer to controlling distortion during any furnace brazing cycle. The real key to controlling distortion is to control the heating and cooling rates used in the brazing cycle. Shown in Fig. 1 is an illustration of what a typical furnace brazing cycle might look like, in which the furnace temp is controlled by the “Furnace thermocouple (TC)” shown on the left side of the chart, and three (3) load TC’s are used on one part to see the temperature-spread (temp-differential, or delta-T) within that one part.