Understanding the plastic behavior of steel plays a crucial role in manufacturing. From raw billet to parts in service, some form of plastic deformation can be found in every step of the manufacturing process, heat treatment not excluded. In fact, I used to joke in Materials and Manufacturing Process class that you should include the words “plastic deformation” in every answer to get full credit. On a macro scale, plastic deformation is simply any permanent shape change to the part. Microstructurally, deformations take the form of atomistic dislocations and planes of slip in the matrix of the base material. Engineers understand plasticity with the classic stress/ strain plot from a tension or compression test,