Normalizing can be described as the heating of a steel product to the Austenite phase. Once the desired temperature has been reached the steel is cooled in air. This normalizes the stresses induced by the previous drawing process.
Various industries often require nonstandard steel tubes. This then has to be drawn down from a mother tube with is commonly rolled off the mill (market standard). The drawing of a steel tube compresses the material which makes the tube brittle and hard. The steel tube then goes through a process called Normalizing, heating the steel tube to the austenite phase and cooling it down in air. This is done mainly to improve the machinability on low carbon steels.