What is Cold Stabilization?
Cold stabilization is a cyclic thermal shock process which is used to reduce the detrimental effects of residual stresses on aluminum alloys. These residual stresses which arise from quenching or the manufacturing processes are dangerous during machining or while in service. Among the more immediate detrimental effects are distortion, a susceptibility to stress corrosion and fatigue. Cold stabilization is a solution to removing these stresses.
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 causes a two fold residual stress situation; a compressive outer shell is in equilibrium with a tensile core. The removal of material post heat treatment 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!
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 velocity steam. Results from this method are verified by the use of x-ray diffraction measurements. This 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 during drafting their own cold stabilization specifications. We also offer our own cold stabilization specifications for all aluminum alloys. Our procedure combines our knowledge, equipment, talented staff and a unique x-ray diffraction stress measurements 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 and cutting tools, contact your Newton Heat Treatment representative today!