What are the difference between Hot Working and cold working?

Please find bellow the defferane between Hot Working and cold working of Manufacturing

SL	HOT WORKING	COLD WORKING
1	Working temperature is above the re crystallization temperature. Therefore, it can be regarded as a simultaneous process of deformation and recovery.	Cold working temperature is below the crystallization temperature.So no appreciable recovery can take place during deformation.
2	Coefficient of friction in hot forming is as high as 0.6.	The coefficient of friction in cold forming i generally of the order of 0.1.
3	hardening due to plastic deformation is completely eliminated by recovery and re crystallization, only if the rate of re crystallization  is higher than deformation.	Harding is not eliminated in this case. This is always accompanied by work hardening.
4	Refinement of crystal occurs.	Grains are only elongated and distorted.
5	Internal and residual stresses are not develop in the metal.	Internal and residual stresses are developed.
6	Surface finishing is not good.	Better surface finishing is obtained.
7	It promotes uniformity of materials.	Uniformity of material is lost.
8	Cracks and blow holes are welded up.	Possibility of crack formation and its propagation is great.
9	Mechanical properties such as elongation, reduction of area, and impact value are improved	Cold working decreases elongation, reduction of area, and impact value.

            Answered by Vivek 
student, OCC (Online coaching Class)
 www.onlinecoachingclass.org