10 Important differences between Cold working and Hot working



Following are the 10 important differences between cold working and hot working


  1. 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.
  2. 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.
  3. Microstructure of cold worked component shows distorted grains, whereas, microstructure of hot worked components shows equiaxed and usually refined grains.
  4. 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.
  5. Cold working cannot be done indefinitely without cracking of material due to strain hardening, whereas, hot working can be done to any extent without cracking due to elimination of strain hardening at higher temperature.
  6. Cold working retains chemical heterogeneity, whereas, hot working removes chemical heterogeneity due to faster diffusion at high temperatures.
  7. During cold working there is no oxidation of metal and hence pickling is not necessary, whereas, during hot working heavy oxidation occurs during working and pickling is required to remove the oxide.
  8. During cold working surface decarburization of steels does not occur, whereas, during hot working surface decarburization occurs at high temperature.
  9. In cold working the surface finish is good, whereas, in hot working the surface finish is not good due to oxidation that takes place at higher temperatures.
  10. In cold working it is easy to control dimensions within tolerance limit, whereas, in hot working it is difficult to control dimensions because of contractions that occur during cooling.

So, these were 10 very important differences between hot working and cold working.

Please follow, like and comment.

THANK YOU.😇😇😇



Comments

Post a Comment

Popular posts from this blog

CONSTITUTIONAL SUPERCOOLING

Image
ABOUT CONSTITUTIONAL SUPERCOOLING Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid. Some of its applications involve refrigeration, organ preservation etc. Constitutional supercooling, is a type of supercooling which occurs during solidification due to compositional changes, and results in cooling a liquid below the freezing point ahead of the solid–liquid interface. This effect occurs when the temperature gradient in the liquid ahead of the interface is small or when interface velocity is large. Constitutional supercooling leads to the formation of dendritic structure during solidification of casting. Fig 1.1 Typical casting grain structure Order of supercooling : Chill Zone > Columnar Grains Zone > Central Equiaxed Chill zone has greater supercooling effect because it is formed when molten metal comes in contact with the cold mould walls. Fig 1.2 The origin of c
Read more

Weiss Zone Law

Weiss Zone Law :- A ccording to Weiss zone law, if a direction [uvw] lies in or is parallel to a plane (hkl) then it should satisfy the condition, uh+vk+wl=0. This law is applied to check whether the direction is parallel to the plane. Which concepts do you want to know from Metallurgy and Materials Science? Comment below!!!!!  
Read more