I want to research the effect of large compressive residual stress
(> 1 GPa ) in a mechanical properties of thick plates made from various metals and alloys .
I know that there is a techniques like shot peening but there effects are only limited to shallow depth in metal parts.
I searched a lot but I cannot find anything relative to that purpose , even using hydrostatic pressing cannot produce such residual stresses . the only thing that inducing compressive stress in a thick metals is autofrettage but it applied only on pressure vesseles not plates , so it is not useful for plates.
So, how to induce such large compressive stresses in thick metal plates if non of these techniques are useful ?
cold rolling cannot applied in high strength alloys due to there low ductility .
Is it possible to weld the plates to create residual stress field?
I think cold rolling using point contact all over the plate will increase Hertzian stresses and thus contribute to the induction of residual stresses.
Dear Abduo,
a way to introduce compressive residual stress in thick plates would be the Laser Shock Peening (LSP) technique. Differently from the Shot Peening (SP) method, LSP is able to introduce plastic deformation in regions of materials lying at deeper positions; usually up to few millimeters, therefore comparable with Autofrettage.
Regards,
Enrico
Dear Abduo Hamed : You can use the link below
http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/10/423/10423784.pdf
best regard
Take for example if you write simple G-code program (Computer aided codes) to polish the surface in different directions. You will see that if your asperities in the [011] directions you will induce residual stresses since your contacts are point contacts and the Hertzian stresses are very large.
You can use Equal Channel Angular Pressing to induce large residual stress in the material. You may apply this technique on fairly large section like I have deformed a 15 mm diameter and 80 mm length billete.
You can introduce thermal residual stresses with rapid quenching the plate from a high temperature into room temperature. In the absence of any phase transformation, you should get tension stresses on the surface layer and compression stresses within the interior of the plate. For the vice versa, you need to know the type of dimensional changes during any possible transformation, then you could guess the type of stresses. i.e. for a medium carbon steel, the surface austenitization and rapid quench results in a compressive stresses on the surface and residual tension stresses within the interior of the steel.
My dear sir:
Residual stresses can be introduced in any metallic plate by vaious methods as mentioned above ,but it will depend upon material composition.So precise answer to your questionis possible only when you share it.However if phase transformation is possible by quenching than R.S. will be generated even after thermal stress relieving by tempering.If quenched high hardness steel plates are tempered for short duration at low temperature and then shot peened you may achieve compressive residual stresses and quantify by XRD.But in case no transformation stresses possible then cold working by cold rolling,extrusion or ECAP process can generate residual compressive stress upto -1000 MPa.
Sure it will depend on the materials. As for copper you can introduce it little easier usingcold work than for steel.
Surface plastic deformation during roller rolling under load. This greater impact compared to shot peening.
Plastic deformation is calculated with respect to reduction in area that is different for different materials. It is a form of cold work that could be manipulated at either line contact or point contact that depend on the residual stress intensity you want to create, and it is much better than shot perming.
I think that the only way to obtain what you expect is to apply a shockwave i.e. the wave generated by an explosion. Quenching is a fine idea you should be aware that this induces compressive strains in the interior the surface being in tension. The strain will not be uniform across thickness.
Quenching will induce compressive stresses but I do not know what benefit we will get here in this case, but raising the cost which is not necessary here. What I stated before is cheaper and suitable for this case.
Under explosive loading, spall fracture and crater can occur.
In addition, there is no sense of a stressed state with high pressure to obtain residual stresses.
Line contact loading are not necessary extreme under cold working condition
Dear Abduo, could you give some more explanation on your final objective? There are ways to have large residual stresses, however most of them are not very straightforward. This also illustrates that in any practical applications, this is not a stress-strain state that is easily reached. So basically the question is, why do you need this residual stresses for? Knowing that would help in picking the most suitable method to induce them.
Residual stresses are usually good for recrystillization after temp relief or for strain hardening depending on the application.
@ Gabi: yes, I agree, but this is a very specific application. For Abduo it is important to specify the objective he has in mind, as for other applications other types/levels of residual stresses might be required. Without this knowledge, this is all 'blowin' in the wind' :-)
It is true. I agree that we need to know the specific application In order to understand his needs.
Laser shock peening(LSP) is one choice. However, please remember these are surface treatment process and therefore the effect is limited to few hundreds of microns, to may be, a couple of mm, depending on the target material and LSP parameters. In some metals repeated LSP has improved the magnitude as well as residual compressive stress (RCS)effected dept. LSP is a non contact process and hence the surface roughness before and after peening is not affected much.Numerous references on LSP on different materials is available in literature.
you can use cold work with hertzian pressure distribution in line contact mode.
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