What is Work Hardening?

Replies

• 

  Ramani Aswath

  That is right. Metals like aluminium and alloys like austenitic stainless steels cannot be heat treated or tempered to a higher hardness. However, they can be work hardened by putting in some energy into them such as by peening, rolling, forging or drawing.
  As the name implies, the material gets hardened by work being done on it.
• 

  the scientist

  sir,,,, my question is when a material is stressed after yield point.....we are saying that nore deforming force is required now to get the deformation.....byt if we have a look at its graph then we will see that now its slope has gone decreased... which means to get on same strain lesser stress is required now..... and what the term ""hardness here reffered to????????????
• 

  Ramani Aswath

  the scientist

  if we have a look at its graph then we will see that now its slope has gone decreased... which means to get on same strain lesser stress is required now..... and what the term ""hardness here reffered to????????????

  That refers to the behaviour of the initial non work hardened material. If you take a piece of the material where it has yielded and repeat the study, you will find that the material has become hard.
• 

  the scientist

  then what???????? then what the meaning of strenghening is?????????????
• 

  the scientist

  however if i apply stress on already worked material . .. it will break !"!""" since we are already close to fracture point!!!!!!
• 

  the scientist

  plz give me full explanation " what do u understand by work hardening"????
• 

  gdchethan

  as i know work hardening is ..........................................................................suppose when i am machining a metal it will get heated up to a certain temperature if i am not using coolant then temperature may even go higher which may cause certain change in properties of that material making it harder and difficult to further machining this is called work hardening.
• 

  the scientist

  good joke!!!!!! ha ha ha
  new comer????
  from which college?????
• 

  gdchethan

  oh thank you dude ......... that may not be the definition of work hardening but it is an example of work hardening,,,,,,,, anyhow i have mentioned at the begining itself as i know............. encourage newcomers 😁🎉
• 

  Ankush Sharma

  dear work hardening is the process in which when we apply force or u can say that stress then the material becomes more harder, so we have to apply more force to break it...
  
  The reason of this is that when we start applying force on some body, firstly it converts from elastic to plastic region so the more force is required to convert to plastic that's why the the slope of stress- strain curve goes on increasing till yield point and then to lower yield point..
  
  But after lower yield point it again starts increasing because when we apply more force the grain structure in the material starts making bond in between them so we have have to apply more force in order to break that bonds which is know as strain hardening or work hardening.. it is the property of material.
• 

  the scientist

  but little knowledge may be dangerous......
  ......................!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"!!!!!!!!!!!!!!!!!!......
• 

  Ankush Sharma

  the scientist

  but little knowledge may be dangerous......
  ......................!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"!!!!!!!!!!!!!!!!!!......

  dear why u write such line, is anything wrong in my explanation??
• 

  the scientist

  no....no that was not for uuuuu
  sorryyyyyyyyyyyyy😀😀😀😀😀😀😀😀
• 

  Ankush Sharma

  the scientist

  no....no that was not for uuuuu
  sorryyyyyyyyyyyyy😀😀😀😀😀😀😀😀

  its okk dear😀
• 

  Kaustubh Katdare

  This thread's going off topic. I might just close it unless it gets back on the track.
• 

  ISHAN TOPRE

  I think #-Link-Snipped-# sir has given a perfect explanation of work hardening. I would like to give a small assignment to all who would like to explore the topic.
  
  1. Explore the possibilities if I cold work steel at temperature less than its Recrystallization temperature. What is the effect on grain size?
  
  2. If I hot work the steel, well above RCT and stop the process before the grains reach their minimum size. What is the effect on grain size?
  
  3. How can I vary the RCT temperature?
  
  4. How can I enhance the plastic deformation zone of given specimen of steel? Will the process be same for samples of different composition?
  
  P.S: Solve for yourself. If any doubt, post it here.
• 

  Ankush Sharma

  Issue

  I think #-Link-Snipped-# sir has given a perfect explanation of work hardening. I would like to give a small assignment to all who would like to explore the topic.

  dear these all are not related to the work hardening. don't go on its name that it is work hardening so it means harden the material. Work hardening simply means that the material becomes harder on applying force in which grain structure start forming bond between them. that's all. But the thing u and bioramani said is related to increase the hardness of material by our self in order to increase the UTS by first heating and then sudden cool. these both are entirely different from each other.
• 

  Ramani Aswath

  Anku2993

  But the thing u and bioramani said is related to increase the hardness of material by our self in order to increase the UTS by first heating and then sudden cool.

  I am afraid that was not what was said. Heating and quenching refers to heat treatment. Certain metals become harder when they are worked mechanically (either hot or cold working). It is the mecahnical work done on the metal that hardens it. Not the heat.
• 

  Ankush Sharma

  bioramani

  I am afraid that was not what was said. Heating and quenching refers to heat treatment. Certain metals become harder when they are worked mechanically (either hot or cold working).

  But dear work hardening is different from it. it doesn't mean to harden the material by heating and quenching or cold treatment. they both are perpendicular to each other...
• 

  Ramani Aswath

  Work Strain Hardening Review Strength ( Mechanics ) of Materials
  nglos324 - workhardening
  
  There appears to be little point in spending more time. Thanks for all inputs.
• 

  ISHAN TOPRE

  #-Link-Snipped-# You might be interested to know the applications of work hardening and heat treatment. Then you will be able to appreciate the difference between heat treatment and work hardening. Do not confuse.
  It is simple, relax 😀
• 

  the scientist

  noone has given satisfactory definition or reason!!!!!!!!!!!!!!!!!😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀
• 

  Ramani Aswath

  This is extensively covered in metallurgical text books. Any standard text will give adequate info, which is why nobody elaborated.
  #-Link-Snipped-#
• 

  Deepak2307

  Hi,
  In this video the professor perfectly explains about strain hardening or work hardening..just a 4min video...superb practical explanation ..
  
  Thanks,
  Deepak
• 

  sahan Pk

  when the material is strain hardened then that will increase in the number of dislocations and increase in their number would lead to their entanglement.so, movement of dislocations would stop and thus there will not be any further deformation up to some extent and thus the material is hardened
• 

  Deepak2307

  sahan Pk

  when the material is strain hardened then that will increase in the number of dislocations and increase in their number would lead to their entanglement.so, movement of dislocations would stop and thus there will not be any further deformation up to some extent and thus the material is hardened

  Hi Sahan, Just some corrections in your answer -- most of the cases, the dislocations don't increase, they rather glide through the structure, Dislocations only increase when there are dislocation sources such as Frank reed sources or a grain boundary source... another thing is with the dislocation entanglement, there is also one more phenomenon which is important, that is when the dislocations come across an obstacle (ex: Grain boundary), it obstructs their movement, hence there's a dislocation pileup... this increases the strength required to deform the material further. In simple words, Work Hardening or Strain Hardening is the work which you have to do to deform the material, as the material hardens, we have to do more work (i.e apply more stress)..hence it is called Strain HARDENING.
  A point comes where the dislocation pileup breaks off the grain boundary barrier, when this happens, the necking occurs, and as now the dislocations can move freely breaking the barrier, less stress is required to deform the material, so therefore after the necking point (UTS), the Stress strain graph shows negative slope.
  
  Thank you.