The drawn form of Cold drawn seamless steel tube
Sep 09, 2021
The current drawing forms are mainly wire drawing, bar drawing, profile drawing and pipe drawing
It is the work hardening of the cold drawn steel pipe. During cold drawing, the metal undergoes plastic deformation, multiple slip systems inside the crystal are activated, and the dislocation movement intercepts each other, and many dislocations are pinned, causing dislocation accumulation, and the dislocation source stops moving at the same time.
The above-mentioned series of processes resulted in a decrease in the mobility of dislocations and a significant increase in the dislocation density in the crystal. When the plastic deformation further occurs, the stress increases and is enough to make the pinned dislocations start to move, the screw dislocations intersect and slip, and the edge dislocations cannot intersect. In this way, the dislocations are intersected and the immovable order increases.
Therefore, the internal dislocation density of the metal is increased by cold drawing, and the mobility of the dislocation is reduced. It is difficult to generate and move the dislocation, so the hardness and strength of the metal material are improved. This is the metallurgical principle of cold drawing.
