Residual stress distribution measurement
Residual stress distribution measurement
(OP)
I would like to know what technique can measure residual stress distribution in coil spring after shot peening.
Currently, I had consulted with XRD's lab and they can measure only stress on outer surface not distribution stress.
In addition, on nowadays technology, which machine or technique can measure residual stress distribution in term of mass production or quality assurance.
Please advise me.
Thanks.
Currently, I had consulted with XRD's lab and they can measure only stress on outer surface not distribution stress.
In addition, on nowadays technology, which machine or technique can measure residual stress distribution in term of mass production or quality assurance.
Please advise me.
Thanks.





RE: Residual stress distribution measurement
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Plymouth Tube
RE: Residual stress distribution measurement
X-ray diffraction is the standard technique used for evaluating residual stress distribution of shot peened springs. The outer layer is first measured, then a small amount of material is removed by electropolishing followed by a second XRD measurement, more electropolishing, a third XRD measurement, etc. This is such an established technique that it is difficult for me to comprehend an "XRD lab" not being familiar with it. If you need experienced labs to perform this, try Proto, TEC, or Lambda:
http://www.protoxrd.com/
http://www.tecstress.com/
http://www.lambda-research.com/
RE: Residual stress distribution measurement
In favor of the electropolishing method is that it does very little to disturb the mechanical structure of the spring. Mechanical machining produces its own residual stresses.
I routinely would process high fatigue parts to a surface residual stress level ~1/3 the yeild strength. (100ksi (275+ksi yield)) I've fatigue tested and seen correlation between cycle count/residual stress/magnitude of alternating applied stress. I have to agree with the current practices at this point.
nick
RE: Residual stress distribution measurement
RE: Residual stress distribution measurement
The drilled hole method has huge uncertainties. It is good at high stresses, but not suitable for low levels.
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Plymouth Tube
RE: Residual stress distribution measurement
I understand there is an ultrasonic machine to get Young's Modulus.
http://ww