Corossion Fatigue

[lLouie]

Hi,

Corrosion has a significant effect on the fatigue of metals. I cannot simulate it directly in the fatigue analysis software, but I am able to modify the surface roughness of the material. How much does surface roughness typically increase after corrosion (as a percentage)?

Ideally, I would like to perform fatigue (S-N) testing on a corroded specimen, but I currently do not have the means to do so. If you can recommend any articles on this topic, I would be interested in reading them.

 

[dgeesaman]

There are a variety of types of 'corrosion': pitting, surface, and intergranular immediately come to mind. As you might imagine, these each have a very different effect on the propagation of a crack tip. Characterization would be complicated and the crack propagation rate is likely inconsistent.

In my experience there isn't much point putting a component into service with fatigue loading if the material will also corrode.

 

[lLouie]

Thank you so much.

Fatigue is already a difficult issue on its own, and corrosion is included, it becomes even more complicated.

 

[mfgenggear]

Thank you so much.

Fatigue is already a difficult issue on its own, and corrosion is included, it becomes even more complicated.

Really not my specialty , but why are you trying
To calculate with corrosion. Object is mitigate corrosion with zinc anodes, coatings or plating, or paint. Low carbon steels will corode in a short
Period if not coated with some type of oil preservation.
All components I have dealt with that were carbon or low alloy steels must be preserved
In some type of oil and packaged to prevent corrosion. Even stainless steel will corrode if
Not protected. Object is not to have corrosion.

 

[goutam_freelance]

There is a book titled Fatigue of Structures and Materials by Jaap Schijve where a chapter is devoted to corrosion fatigue. You will also get a number of references to published papers there on this subject.

 

[lLouie]

Really not my specialty , but why are you trying
To calculate with corrosion. Object is mitigate corrosion with zinc anodes, coatings or plating, or paint. Low carbon steels will corode in a short
Period if not coated with some type of oil preservation.
All components I have dealt with that were carbon or low alloy steels must be preserved
In some type of oil and packaged to prevent corrosion. Even stainless steel will corrode if
Not protected. Object is not to have corrosion.

I just want to see the effect of corrosion on life. I can't get a test done, so I'm just trying to figure it out by changing the surface roughness in the analysis program.

 

[lLouie]

There is a book titled Fatigue of Structures and Materials by Jaap Schijve where a chapter is devoted to corrosion fatigue. You will also get a number of references to published papers there on this subject.

Thank you

 

[mfgenggear]

I just want to see the effect of corrosion on life. I can't get a test done, so I'm just trying to figure it out by changing the surface roughness in the analysis program.

google the effects of stress corrosion cracking and the effects on steel.
depending on the application , stress loads and moments. stress risers with pitting then crack propagates.

 

[cnc king]

The increase in surface roughness after corrosion depends on several factors, including the type of corrosion, the corrosive agent, the duration of corrosion, and the material properties. Generally, corrosion leads to an increase in surface roughness, with the specific percentage increase ranging from a few percentage points to several tens of percentage points.

For specific materials and corrosion conditions, it is best to conduct experiments or refer to data in the literature to obtain more precise information. Typically, the increase in surface roughness after corrosion can alter the fatigue properties of the material, so these factors need to be considered in fatigue analysis.