Tensile Testing Question 2

[ME231]

Dear All,
We currently outsource all of out tensile testing jobs. However, due to various reasons, we have been mulling the idea of bringing the work in-house. We need to perform tests per both ASTM (E8) and EN (EN10002-1 and EN10002-5) specifications on a regular basis.
I foresee problems with calibration as both these sets of American and European specifications seem to demand two differing sets of calibration requirements.
Can you all please advise me if this might be a problem in the long run? How difficult would it be to switch from one calibration standard to the other?
Any help/direction from the forum would be much appreciated.
Thanks...

 

[Ron]

Machines and devices are calibrated...techniques and procedures are not. You should calibrate your devices to both standards...that's not a big deal. You can then test to any standard necessary, since your devices will have been calibrated to either criteria.

 

[ME231]

Dear Ron,
Thank you for your response.
The outside vendor we currently use maintains two different machines calibrated to the two standards/specifications. I extrapolated this information to draw a conclusion that they did it because of difficulties with switching between standards. Do you not believe this to be the case?
I have limited experience with using the ASTM/EN calibration standards and therefore seek your advice.
I appreciate your help.
Thanks...

 

[EdStainless]

We actually have different extensometers and dual load sensors. The difference in calibration methods is a pain but not impossible.
If you do a lot more work in one system over the other then set up to do the major one in house and send the other one out.

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Plymouth Tube

 

[ME231]

Thanks Ed for your response.
Our volume of work is actually fairly evenly divided between the two systems. Can you advise me as to where the calibration would typically be done - on site or at the load cell/extensometer manufacturer's site?
Also, do you think it might be possible to lay down a common minimum denominator and calibrate to the more stringent values from the two standards?
thanks...

 

[Ron]

ME231....as long as the testing did not exceed the yield strength of the material, it is OK to run the test again.

Compare your most recent results to the original separation documents. Reject if unacceptable.

 

[EdStainless]

No, they require different methods for calibration. It is a pain in the butt

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Plymouth Tube

 

[ME231]

EdStainless, would you think it might be possible to maintain 2 load cells based on the two differnet calibration standards. if I were to not use an extensometer, would that simplify things?
thanks for your input...

 

[EdStainless]

actually you could use one load cell and have it calibrated both ways. I know a shop in town that has two machines, one runs ASTM/ASME and the other ISO/EN

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Plymouth Tube