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10 Important differences between Cold working and Hot working

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Following are the 10 important differences between cold working and hot working Working of metal and alloy below their recrystallization temperature is known as cold working , and working of metal and alloy above their recrystallization temperature is known as hot working . During cold working strain hardening occurs and due to this tensile strength, hardness increases while the impact strength and ductility decreases, whereas, due to hot working strain hardening is removed by recrystallization. Microstructure of cold worked component shows distorted grains, whereas, microstructure of hot worked components shows equiaxed and usually refined grains. Due to cold working defect density increases i.e. vacancies, dislocations, etc. increases and hence the density of material slightly decreases, whereas, due to hot working there is almost no change in defect density of material. Cold working cannot be done indefinitely without cracking of material due to strain hardening, whereas, ho
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Metal Working At High Temperatures.

Here we will be dealing with different metal working processes, their parameters, their effect on mechanical properties and more... First let's see the classification of metal working processes based on the types of forces applied on the workpiece. Direct Compression type:  Examples are Forging, Rolling. Indirect Compression type:  Examples are Extrusion,Wire drawing, Deep drawing. Tension type:  Example is Stretch forming. Bending type. Shear type. Working Process Parameters: Working process parameters are mainly flow stress, strain, strain rate, temperature of working. All these parameters are interdependent i.e. changing one will affect the other. Now, in this study we are dealing basically with high temperature effects so all the metal working process parameters will affect the flow stress but "strain" will have negligible effect on flow stress , instead in high temperature working strain rate will play an important role.... Let's discus
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FORMULAS OF TRUE STRESS AND TRUE STRAIN

TRUE STRESS: Formula for true stress is, σ t =σ e (1+e). where, σ t =True stress. σ e =Engineering stress. e=Engineering strain. TRUE STRAIN: Formula for true strain, ε=ln(1+e). where, ε=true strain. DO ASK ANY QUERY IN COMMENT BOX.  
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