Bainite is a phase in steel that can be created by heating the steel up to an austenitic temperature followed by a designed cooling procedure. An interesting fact about bainite is that it was previously developed under the name troostite.

When heat treating a steel to make it hard or create alternative structures, there are three conditions that are necessary to accomplish the required phase change. They must be adhered to in order to accomplish the desired phase. These three conditions are carbon content, temperature and cooling rate.