How shot peening and grain coarsening impact the high corrosion resistance of the steel. Is there any significant results where the oxidation resistance of the given material improves by the grain coarsening.
Shot peening improve the strength of the steel surface, but not its oxidation resistance. The composition of the steel plays a decisive role in the oxidation resistance. An additional small effect is the surface finish: the smoother the surface, the higher the oxidation resistance at the beginning of the high-temperature works (after long operation, the oxidized surface becomes rough and initial state no longer plays a role).
In this sense, the polished surface is better than a shot peened surface and the worst is roughly ground or sand-blasted surface.
Dear Sumit,
While composition and surface finish are crucial factors in deciding the oxidation resistance of steels in general, as correctly pointed out by Dr. Verlotski, in case of passivating steels the plastic deformation caused by shot peening does have a beneficial effect.
It appears that you are working on austenitic steels, so this would be relevant for you. The basic concept is that uniform plastic deformation increases the defect density, which provides more diffusion paths for Cr to form a stable Cr2O3 film on the surface. As for grain size, finer grains give more grain boundaries, thus adding to the defect density. Considerable studies have been done in this area. The recent paper attached may be of use to you:
https://link.springer.com/chapter/10.1007/978-3-319-48765-6_28
Do contact me if you need more literature or are looking at a specific condition.
Good luck!
I am no expert for steel or any other material but I tendentially agree with Aashranth B. Any change of a materials surface will have some impact on the surface property. It might be that for some materials shot peening does not affect the oxidation in a measurable way (since oxidation is in many derictions a mystery) but since you damages the microstructure dramatically it can have a protective but also a disadvanteous inlunece of the oxidation. Finally, it depends on the main mechanism which will vary from material to material. Sometimes, the diffusion out of the material (e.g. the mentioned Cr) is controlling the oxidation, sometimes the diffusion of O into the material trough the high-defective zone is dominant. Or you still have other parts of the atmosphere like water, sullfur (S02) etc which may damage your material in a way you have never expected or seen before. As I said: it is a mystery...and would be very valuable if someone would be able to predict this. However, nature is commonly quite unpredictable...
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Metals
- Alloys
- Steel