×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

AISI 301 - SN Curves

AISI 301 - SN Curves

AISI 301 - SN Curves

(OP)
Hi everyone,

I am working on fatigue analysis with a AISI 301 material (austenitic stainless steel). I'm looking for a S-N curve which describe the behavior of this steel when it undergoes  a reversal tensile stress (R=-1).
I've already looked in MIL-HDBK-5, unsuccessfully.
Is there another way to approach these data (theoritical plot, similar steel...)

Thanks in advance.

Best Regards,

Antoine L

RE: AISI 301 - SN Curves

whilst i haven't ny info, you'll need to specify the hardness, this has a major impact on fatigue life

RE: AISI 301 - SN Curves

(OP)
Rb1957 -> I don't know the hardness, the only data i have are:

-Fty: 135 ksi (930 MPa)
-Ftu: 168 ksi (1158 Mpa)
-thickness: 0.5 mm


TVP -> Thanks for this article, i think i saw it but the curves didn't inspire me, I was only looking for typical S-N curve (Cycle/Stress).

RE: AISI 301 - SN Curves

Sorry I wasn't able to provide more inspirational data.  If you can't use the data from the Outokumpu document to estimate the problem you need solved, then you probably need to review some background information on fatigue.  The fatigue calculator website has some good fundamentals:

http://fatiguecalculator.com/

FYI, you are not really going to find free S-N curves for Type 301 stainless steel (spring temper) just lying around the ether.  This sort of testing is incredibly expensive, costing ~ $500 or more per data point, which is why companies that pay for it don't subsidize the rest of the world and make it freely available.  Good luck with your project.

RE: AISI 301 - SN Curves

antoineL

Knowing:

-Fty: 135 ksi (930 MPa)-Ftu: 168 ksi (1158 Mpa) and knowing that R=-1 you can calculate the number of cycles given you are familiar with basic fatigue theory. If you don't, you should look for a qualified engineer or use any college grade book for machine design such as from Shigley, Faires, Norton, etc.

RE: AISI 301 - SN Curves

(OP)
Thanks all,

I've already plotted a theoretical SN curve with basic formulas such as Se=0.5*SU; Sf=1.62*Su*Nf^-0.085; etc.
But the fact is that my results (Life prediction in hours, Number of cycle...) hugely depends on the shape of the SN curve and modifying factors. Now my goal is to assess that this result is "accurate" enough. Of course the best way to do that would be to run some test but as TVP said, it's really expensive. So I want to compare a maximum of S-N curve in order to confirm my first result.

An other question: If fatigue tests have been conducted in rotational bending, is it acceptable to say (or conservative) that Se(axial)=0.7*Se(bending) & Te(torsion)=0.577*Se(bending).

Again, thanks

RE: AISI 301 - SN Curves

The S/N curve is only the beginning. You have to take into account the factor numbers due to surface condition, roughness, size, stress concentration, etc,. In fatigue analysis a common factor of safety is 4 to 10. Finally, an actual cycle test may be needed to prove your design.
 

RE: AISI 301 - SN Curves

can you do a fatigue test to verify the design ?

135ksi steel is just over 1/4 hard (that'd be 125ksi).  

this should be pretty tolerant for fatigue, a fatigue cycle of 1/4 to 1/2 Fty should give you a reasonable life; depending on Kt.  if you want infinite life, maybe 0.10Fty.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources