Chromium Vanadium S-N curve
Chromium Vanadium S-N curve
(OP)
Hello Everyone,
Can somebody tell me where i can find an S-N curve for this material, specifically for the SAE 6195, or any grade of chromium vanadium?
The problem is that i'm trying to calculate analytically the correspondent stresses for infinite life (10^6 to 10^7) in order to make the curve, having already calculated the endurance limit (Shingley Mechanical). I want to put these values in Ansys, however analytical formulas don't reproduce the real life S-N curve, obviously, because the material in this case is tested in laboratory and in rigorous conditions.
Thanks a lot,
David Marques
Can somebody tell me where i can find an S-N curve for this material, specifically for the SAE 6195, or any grade of chromium vanadium?
The problem is that i'm trying to calculate analytically the correspondent stresses for infinite life (10^6 to 10^7) in order to make the curve, having already calculated the endurance limit (Shingley Mechanical). I want to put these values in Ansys, however analytical formulas don't reproduce the real life S-N curve, obviously, because the material in this case is tested in laboratory and in rigorous conditions.
Thanks a lot,
David Marques





RE: Chromium Vanadium S-N curve
Anyway, if you really want to build the entire S-N curve, considering that your fatigue limit is already approximated, you can assume a fatigue strength equal to 0.9 UTS at 10^3 cycles and connect the two points with a straight line.
RE: Chromium Vanadium S-N curve
I believe SAE 6195 is an obsolete alloy designation, but you'll have to check SAE J1249 to be sure.
Out of curiosity, do you have some specific application in mind for this material? SAE 6195 is a high carbon Cr-V steel, and it was typically heat treated to very high through hardness for applications like roller/ball bearings. Given how this material was typically used, I don't think you'll have much luck finding any tensile fatigue data for it.
RE: Chromium Vanadium S-N curve
I have only one objection, full hardening steels are actually finding an increasing use in diesel fuel injection equipment, and in such application the knowledge of fatigue data is of great relevance due to the high pressures involved.
RE: Chromium Vanadium S-N curve
Thank you people or the responses. i had to calculate the stress to the correspondent cycles to make the curve i had no other choice because i could not find the S-N. however i find a bit weird why is it so difficult to find S-N curves for steels online because all the materials have to be teste before going to the market. I was making my final projet in mechancial engineering and the object of interest was a bearing puller. Everywhere i look online about the material for the pullers they all say that is chromium vanadium but i read some comments where they say very rarely pullers are made of this material and its all a bunch of lies. The producers that put their products on amazon for example say they are made of this material because it looks great for the consumer because it is a high quality steel. However in reality its not. However as long as my calculations are correct i am happy.
Cheers,
David Marques
RE: Chromium Vanadium S-N curve
your calculations are correctyour prediction leads to a reliable and cost effective product, you're happy: Keep it in mind, numbers are easy to "adapt" so to demonstrate that everything is compliant, but then reality will spoil the inaccuracies you painfully tried to cover.RE: Chromium Vanadium S-N curve
Do you have access to the latest copy of the MMPDS?
These are alloys for aerospace use and they have well defined strength and fatigue data. One thing that you will notice is how few alloys are listed.
That is how it works. The more complete the characterization the fewer grades you will find.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Chromium Vanadium S-N curve
Thanks a lot for the feedback. I already finnished my projet. I calculated the endurance limit in "Shingley" and made the S-N curve out of it, because it is a more realistic approach of what this material would suffer from a real life fatigue (because it counts factors like temperature, surface finishing, size factor , load factor etc). Any S-N curve is data that is extracted from laboratory from very specific conditions, which isn't the case, just like this puller or basically any other tool.
Is this logic that applied correctly made?
Cheers,
David Marques
RE: Chromium Vanadium S-N curve
Just to make sure we understand each other:
- S-N curve -> used for finite fatigue life
- Fatigue limit -> used for infinite fatigue life
All modifying factors you mention usually apply to the fatigue limit only and are therefore used in the second approach.The S-N curve, although primarily derived from standardised specimens in strictly controlled laboratory conditions, is a more versatile tool that can be applied directly to real components (for example, curves were developed for gears and welds). Needless to say, the more boundary conditions you introduce, the less general is the outcome of your test and therefore its applicability to different scenarios. Since in many practical cases an approximate S-N curve is sufficient, one can build it using basic material properties (typically tensile strength) under certain assumptions.
RE: Chromium Vanadium S-N curve
Quote
"I was making my final projet in mechancial engineering..."
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RE: Chromium Vanadium S-N curve