Another shaft fracture 7

[Hercules28]

Dear all,

I will come up with more details on what happened but this fracture surface looks like a fatigue overload failure. What do you think?

 

[metengr]

Ratchet markings along the periphery combined with what appear to be one or more circumferential crack arrest lines looks like evidence of fatigue crack propagation.

 

[desertfox]

Definately fatigue by the look of it and just looking at the picture it looks as though the centre of the shaft is raised up compared to the outer is it?

 

[desertfox]

The site below might help:-

http://www.plant-maintenance.com/articles/rcfa.shtml

 

[stanweld]

Looks like torsional fatigue failure. What was the material and was it case hardened? The fracture surface is out of focus on the right side.

 

[swall]

That is a classic rotary bending fatigue failure for a shaft.

 

[Guest102023]

Classic rotating bending (not the same as torsional) fatigue.

The relatively small area of final fracture indicates a low mean stress.

 

[desertfox]

Checkout pages 13 and 14 on this link:-

http://www.asminternational.org/pdf/spotlights/jfap0502p011.pdf

 

[Guest102023]

Excellent find, desertfox.

The charts in the ASM Handbook showing sketches of various fatigue fracture appearance is very useful in categorizing failures.

 

[desertfox]

Hi brimstoner

Your very welcome!

 

[Hercules28]

Desertfox, I think that seals the deal right there. Thanks, great help.

 

[desertfox]

Your Welcome

 

[mfgenggear]

desertfox

ditto
nice post

mfgenggear