Normalizing Heat Treatment
What is Normalizing?
Normalizing is a heat treatment procedure that focuses on the mechanical properties of steels. It is used to reduce residual stresses and thereby improve tensile strength and impact value for increased resistance to brittle fracture and corrosion.
For normalization to occur, steel is heated to a temperature slightly above its upper critical transformation point. The steel is then held long enough for smaller metal grains to form and high-energy grain shapes to come together. This transformation is called grain refinement and leads to the formation of a more uniform piece of metal.
Due to the high temperature needed to heat a ferrous alloy (a metal whose composition contains mostly iron), such treatments are not easily accomplished outside proper heat treatment furnaces. However local normalizing on institute piping and components can be done utilizing special techniques which Superheat is well versed in. To complete the process, the metal is then cooled in still air (air quenched) to a temperature substantially below the upper transformation range. The rate of cooling in normalizing is generally not critical, but aids in the hardening of the work piece.
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