“Solution Treatment” or “Solution Anneal”, is the first step heat treatment of “precipitation” or
“age” hardening metal alloys.
Solution treatment temperatures are relatively high to achieve rapid diffusion to achieve a “solid
solution” of elements. The temperature required is dependent on the alloy. Iron and Nickel
alloys near 2000 deg F. Aluminum alloys near 1000 deg F, still high relative to their melting
point.
It also takes time at these temperatures for diffusion to distribute the constituent elements
uniformly throughout. Time required is dependent on the metal and alloy in question.
The cooling rate from the solution temperature needs to be rapid enough to temporarily
suppress the precipitation of elements from solution. Again the cooling rate required is
dependent on the metal and alloy in question.