What is the difference between mill annealed and solution annealed material?
A. They are both standard annealing practices, which place materials into their “soft” conditions. The mill anneal is conducted at a lower temperature than the solution anneal e.g. 1950F(1066C) versus 2150F(1177C). However, the solution anneal is high enough to redissolve all carbides and intermetallic phases and take them into solution while a mill anneal allows redistribution of carbides by diffusion. Also, holding for longer times at the higher temperatures can result in large grain and grain growth.
