Fatigue stress concentration factor Kf of 316 stainless steel 1

[fairbairn]

We have a corroded 316 SS shaft and we have ground out the corrosion. We could not exactly match radii in the FEA model, so I am looking for the stress concentraction factors Kf of 1.5mm and 2.5mm for 316 stainless.

 

[metengr]

Are you sure about Kf or are you interested in Kt? Stress concentration factors (Kt) are not material specific, they are based on geometry. If you need to calculate a Kt factor see the web site below;

http://www.fatiguecalculator.com/finders/findkt.htm

Kf = 1 + q(Kt-1)

q=notch radius (normally between 0 to 1). This value depends on material and notch radius.

 

[fairbairn]

This is a useful site, but I really need either Kf or notch sensitivity factor q for 316 stainless!

 

[metengr]

fairbairn;
There are published q (notch sensitivity) curves based on notch radius and material tensile strength. Once you locate the q value (see “Deformation and Fracture Mechanics of Engineering Materials”, Hertzberg, page 430). If you know the notch radius you can pick off the corresponding q value based on ultimate tensile strength. Once q is known use the equation above to determine Kf.