9310 Fracture Mechanics Properties

[UCengno1]

Am searching for fracture mechancs properties for 9310 alloy steel. Need for input to NASGRO. Any idea where to look? I have a couple of the easier to find properties but the crack growth properties are evading me. Any help is greatly appreciated?

BCK

 

[metengr]

I have a demonstration version of NASGRO that I downloaded a while back to evaluate purchasing it and there is information for 9310 under the tab AISI steel. I did not purchase the software so I can't access the entire database.

 

[TVP]

The following data is from Engineering Fracture Mechanics 72 (2008) 1148-1170 which was written by researchers from Cornell Fracture Group & US Army:

Young's modulus 30,000 ksi
Poisson's ratio 0.3
Tensile strength 185 ksi
Yield strength 160 ksi
Fracture toughness, KIc 85 ksi in.^1/2

Paris model parameters of AISI 9310 steel:
C 6.19 x 10^-20 (in./cycle)/(psi in.^1/2)ⁿ
n 3.36

http://www.sciencedirect.com/scienc...serid=10&md5=7f4c4fadb4a013db3c8a3807b90932b5

 

[CoryPad]

Is this for a carburized part? The graded microstructure will have variable fracture properties.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[UCengno1]

Yes it is carburized. Does variable mean directional or just dependent on the specific carburize results?

 

[CoryPad]

It means the fracture properties vary through the part, just as the microstructure varies through the part. Analysis software almost always assumes the material is a continuum with constant material properties, which is a reasonable assumption for a part like a cylindrical shaft that has been through hardened and tempered. For a part that has been carburized case hardened, there is a gradient to the microstructure, residual stresses, and mechanical properties. These complicating factors mean that parts usually are tested physically rather than computationally.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ScottishMet]

The strength level quoted in the Engineering Fracture Mechanics 72 (2008) 1148-1170 is very high and consequently the toughness lower than normal.
Core strength properties of 9310 material which has been through a carburize cycle are more typically UTS 140 - 150 ksi, YS 100 - 125 ksi
Fracture toughness, KIc 125 ksi in.1/2

 

[TVP]

UC,

Another source of gear failure prediction info is the article "Predicting Remaining Life by Fusing the Physics of Failure Modeling with Diagnostics" that appeared in the March 2004 issue of JOM. It was authored by researchers from Impact Technologies LLC and the US Navy. This discusses all of the relevant issues, including 3D stress analysis, residual stresses, variable microstructure, etc. A reprint of the article can be obtained by using the following link:

http://www.cimss.vt.edu/PASI/lectures/roemer/JOM_V3.pdf

 

[unclesyd]

Depending on your available data that might be of some assistance.

http://www.fatiguecalculator.com/

On the following site look at the Bar Steel Fatigue
Database and Bar Fatigue Blog.

http://www.autosteel.org/AM/Templat...aggedPageDisplay.cfm&TPLID=11&ContentID=21897

Some papers that might be of interest.

http://www.alphastarcorp-genoa.com/Publications/SAMPE2002/Final-Paper-Probability-ASTM-R1.pdf

http://www.volpe.dot.gov/sdd/docs/fatigue-1006-final.pdf