Profile: Gloucester Heat Treatment Ltd. is a provider of heat treatment services for ferrous and non-ferrous materials to commercial and aerospace industries. We are an ISO 9001:2008 certified company. The purpose of heat treating aluminum is to increase the strength and hardness of the alloy. Solution heat treatment on its own, initially increases the ductility of alloys, and enables a certain amount of cold working to take place: bending, forming, stretching, before natural aging starts to harden the metal.