Reuse of Stud Bolts/Used Stud Bolts

[cwood3]

Beyond good engineering practices and quality issues in general (also PCC-1, Appendix N), are there any specific codes, regulations, guideline, recommended practices for reusing stud bolts for flanged connections on either pressure vessels and/or pressure piping?

I do not want to use old/used/etc stud bolts but I have a client that sent me an inquiry on this topic.

Thanks,

cwood3

 

[Frank1344]

cwood3,

Did you look into API-RP570?

It does have a clause 5.12 Inspection of Flanged Joints.

Cheers,
Frank

 

[gr2vessels]

Frank,
API 570 Clause 5.11 Inspection of Flanged Joints doesn't address the issue of reusing stud bolts. Is there any better reference?
However, just for comparison, every time you open a flanged joint, you are reusing the old stud bolts (unless you have reasons to replace them). Conversely, I would say that the bolts used in a similar environment and not subject to advanced corrosion can be re-used for continuing service. I assume the type and size are identical to the calculated/designed ones. This judgement doesn't include the unknown source of bolts and nuts.
I don't know any standard allowing you to inspect and test the bolts before installing them in operation, but many NDE companies offer Dye Penetrant and Magnetic Particle testing for fine discontinuities on the studs surface.
It all comes down to the costs involved, sometimes the inspection costs could overrun the new bolts cost. One thing for sure, the cost of new bolts will always be lower than the cost of joint failure and the subsequent disaster caused by bolts failure.

 

[metengr]

I agree with the above advice. If you intend to re-use studs because of limited availability or other problems related to supply, they should be carefully inspected for cracks using Liquid penetrant or wet fluorescent MT. Exposed threads should also be visually inspected and checked with a thread gage.

 

[puigi]

Beyond whatever NDE you perform dimensional acceptability standards for visual inspection of threaded fasteners can be obtained from ASME B1.3M & Federal Standard H28 Document 20.
Another consideration for re-use would be if the fasteners were stretched past their yield point during initial installation.

 

[fegenbush]

puigi brings up an interesting point. SAE allows for TTY (Torque to Yield) bolts. Bolts (or studs) specified as TTY are not to be reused.

/I realize that SAE standards are not applicable to flanged joints, but that was used as an example.

 

[cwood3]

Thanks guys. I relayed the info and had a discussion with my client. He's got a better feel for how to deal with it.