Accuracy of Tensile Testing 304SS Micro-Tubes
Accuracy of Tensile Testing 304SS Micro-Tubes
(OP)
Hi All
I am looking to find out if anyone has any input on whether tensile testing a micro-tube (OD 0.66mm, ID 0.48mm) made from 304ss would be accurate enough to derive material properties e.g. tensile modulus, uts, yield stress etc..
Or is it more appropriate to use larger, solid cross-section test samples?
I ask as the testing I have done, yields very high (>1200 MPa) strengths compared to what I know to be the UTS of 304ss (~550 MPa) and am unsure if theres something simple i am missing?
Any guidance at all would be great as I am very rusty on my materials and could use the help!
Thanks
I am looking to find out if anyone has any input on whether tensile testing a micro-tube (OD 0.66mm, ID 0.48mm) made from 304ss would be accurate enough to derive material properties e.g. tensile modulus, uts, yield stress etc..
Or is it more appropriate to use larger, solid cross-section test samples?
I ask as the testing I have done, yields very high (>1200 MPa) strengths compared to what I know to be the UTS of 304ss (~550 MPa) and am unsure if theres something simple i am missing?
Any guidance at all would be great as I am very rusty on my materials and could use the help!
Thanks
Regards,
Tom





RE: Accuracy of Tensile Testing 304SS Micro-Tubes
Typically, tensile testing is performed to a standard, like ASTM A 370, for proper comparison and determination of mechanical properties. It is possible your higher tensile values are due to processing effects, like cold work, that can result in higher tensile values as a result of work hardening.
RE: Accuracy of Tensile Testing 304SS Micro-Tubes
Thanks for the reply. I tensiled some samples, to ASTM A370 annex A2, parts were held by pneumatic grips. The tubes were formed via extrusion, but past that have not seen any more processing. The failure was also as expected.
Regards,
Tom
RE: Accuracy of Tensile Testing 304SS Micro-Tubes
RE: Accuracy of Tensile Testing 304SS Micro-Tubes
1200 MPa isn't out of the question, but I would expect very low ductility at this strength.
And they should be highly magnetic.
Did you put pieces of wire into the ends so that you could grip them without crushing them?
I have tested wire down to .05mm diameter, just takes more care.
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P.E. Metallurgy, Plymouth Tube
RE: Accuracy of Tensile Testing 304SS Micro-Tubes
If you want properties of the bar, you have to test the bar.