Dear guest, you must be logged-in to participate on CrazyEngineers. We would love to have you as a
member of our community. Consider creating an
account or login.
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.
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????????????
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.
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.
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 😁🎉
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.
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.
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.
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.
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...
#-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 😀
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
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.
