Effect of uphill quenching on residual stresses and properties of aluminium alloy D16

The results of heat treatment including quenching in water, uphill quenching (cooling to the liquid nitrogen temperature, holding at it and heating in hot mineral oil) and natural or artifi cial aging on hardness and corrosion properties of the wrought thermally hardening aluminium alloy D16 are presented. The effect of heat treatment on the residual stresses is studied by drilling method. The recommendations concerning the usage of this heat treatment to reduce residual stresses and warpage are given.

Uphill Quenching of Aluminum Alloys

This article describes the concept of uphill quenching process applied in the heat treatment of aluminum alloys. Uphill quenching is interesting since residual stress reductions of up to 80% has been reported. In addition, substantial improvements in dimensional stability have been achieved for several types of aluminum parts. Often, uphill quenching is applied after quenching and before aging during the heat treatment of aluminum alloys. The uphill quenching process consists of the immersion of the part in a cryogenic environment, and after homogenization of the temperature, the part is transferred to the hot steam chamber to obtain a temperature gradient that will maintain the mechanical properties gained with this process. The results obtained are lower residual stress and better dimensional stability. The aim of this article is to provide a review of this process and to compare it with conventional heat treatment.