Structural Integrity on Metal Under Compression

Well, the tube can only behave according to the difference in pressure between inside and outside, Guv. You work it out.

we know the tube and workings are the same as if we are testing here in the factory but its the effect on the tube wall under compression at this depth from these 2 pressures that is required and what different effects it may have on the function of the tube.

Come on, Uncle. Your mechanical engineers can work this out, surely?

Is the bourdon tube exposed to sea water?

the bourdon tube is not exposed to the sea water, the case of the gauge is filled with silicon oil, in the gauge is a back plate with a rolling type diaphragm fitted to it which transmits the ambient pressure to the inside of the gauge case and also the surface of the tube, this design fitted in conjunction with a compensated system, on R.O.V.s for example, is what gives the gauge its ability to be used at almost limitless depth. We have manufactured these gauge for over 20 years now with not a single failure but someone has posed the question of the material walls structural integrity in this operation.

Why are you wasting time investigating a non-problem?

No exposure to harsh environment, no failures in 20 years, What's the problem?

The only failure mode that comes to mind is work hardening of the tube over time and this doesn't seem likely with the small amount of movement in this case.

I completely agree with you but our customer has posed the question put to him by his customer who is allegedly an expert and reckons there is a potential issue? yet he wont provide me with any info to back up his concerns. I am just an employee doing what is asked of me to best of my ability, i have pretty much given up on this now as searching for info that doesnt seem to exist does my head in..

thanks anyway

You have my sympathy.

This "expert" sounds like some insecure person who has the need to demonstrate his superior intellect.

Anybody who won't accept that much historical data that it's a non-problem isn't being realistic.

Good luck.

You might take a look on MatWeb for some help, or engineering toolbox.