Cold Stabilization
Cause & Effect: By the nature of the quenching operation of aluminum alloys the outer surface of the material cools at a more rapid rate than the interior. This causes the not yet cooled center to pull against the hardened outer "shell", thereby creating quenching residual stress. The quenching operation generally causes a two fold residual stress situation; a compressive outer surface is in equilibrium with a tensile center section. The removal of material during machining causes a redistribution of these stresses. A part high in residual stress cannot maintain dimensional stability during or subsequent to machining operations. An imbalance in these stresses may cause a part to warp or rupture, either on the shelf or in service!
Solution: Cold stabilization, also known as "uphill quenching", is the cycling of parts above and below room temperature. It is possible to counteract quenching stresses by subjecting a part to -320¡F and rapidly shocking the part by blasting all surfaces with high pressure steam. Results from this method are verified by the use of x-ray diffraction analysis. Sophisticated stress analysis is not usually associated with commercial heat treating however at Newton Heat Treating it is. Many "Prime" aerospace companies have consulted with Newton Heat Treating in the writing of their own cold stabilization specifications. We also offer our own cold stabilization specifications for all aluminum alloys. Newton's procedure combines their knowledge, equipment, talented staff and unique x-ray diffraction stress analysis to offer efficient service, product integrity and reproducibility. Cold stabilization offers a new dimension in quality control and dependability. Newton Heat Treating is the only company that can offer this cost-effective service.
For details on how this incredible process affects different aluminum alloys as well as steels, and cutting tools, contact your Newton representative.