work hardening

[Jan]

Mike's latest Sharp Pad videos are fascinating. Especially interesting was his discussion of work hardening when removing the burr with the Sharp Pad. I would like to learn more about this.

Ken, work hardening which is also known as strain hardening or cold working is a metallurgical process of metal strengthening by means of its plastic deformation. Plastic deformation occurs when energy is quickly added to the metal. The work hardening of a metal increases its hardness and yield strength. The reason for metal strengthening is movement and generation of many new dislocations within the metal atomic lattice.   

Here is a classical text book example: "Strain hardening can be easily demonstrated with piece of wire or a paper clip. Bend a straight section back and forth several times. Notice that it is more difficult to bend the metal at the same place. In the strain hardened area dislocations have formed and become tangled, increasing the strength of the material. Continued bending will eventually cause the wire to break at the bend due to fatigue cracking."

https://www.nde-ed.org/EducationResource...hening.htm

Jan