inspection of re-use stud bolt 2

[91873634542]

hi All,

could you inform me some parameter that state a stud bolt can be re used ?
this application for pressure vessel

thanks a lot for the advise

BR
EP

 

[fegenbush]

In my experience, the ability to be reused is not relevant, as most of the repair crews with whom I have worked would simply cut the stud bolts with a torch. This, of course, applies to carbon steel fasteners only. Stainless steel fasteners are likely to be galled or seized and must be cut off by abrasive wheel or other means. I suppose other exotic fasteners may be economical to reuse, but that would depend on the material specification and specifics of installation.

 

[LittleInch]

The usual issue is that, by simple visual inspection, it is impossible to know if the stud bolt has been subject to

1) Fatigue loading leading to microscopic cracks, especially in the bottom of the grooves
2) Over stress leading to plastic deformation and potential work hardening
3) What the actual bolt material is and its yield strength
4) If its been subjected to excess heat or bending

Basically too many unknowns to take the risk of failure compared to the cost of new stud bolts...


My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Why is maximizing false economy such a strong driver??????????
I don't have enough question marks for that.
Ask the CFO what he thinks. Even they get it.
Why is it such a problem for engineers?

I hate Windowz 8!!!!

 

[BigInch]

We'll add 10% to any pump's flow rate, but throw away a perfectly good bolt... never.

I hate Windowz 8!!!!

 

[MJCronin]

A more authoritative discussion of the topic is contained here:

http://www.fastenal.com/content/feds/pdf/Article - Reuse of Fasteners.pdf

(It should be understood by all that Fastenal, of course, sells fasteners)

The AISC people have instituted a flat ban on bolt reuse.....

http://www.portlandbolt.com/faqs/rules-for-reusing-bolts/

Some reasonable rules of thumb for fastener reuse could be developed specifically for each facility.

The rules could involve:

- High Temperature Service
- Cost of Bolt materials
- Corrosive service
- Risk of joint failure

MJCronin
Sr. Process Engineer
Venture Engineering & Construction

http://www.VentureEngr.com

 

[Duwe6]

What MJCronin said, plus the cost of Downtime due to possible fastener failures; the cost of man-hours to clean the threaded areas to allow meaningful inspection, and get the threads smooth enough to allow meaningful torque-vs-pretension values. Unless you forgot to stock fasteners on-site, they are too cheap to risk reuse. Unless your workers are being paid VERY little, you will pay more to clean & inspect old bolts than you will pay to install new stuff.

I can save you $$$ by only changing the oil in your car every 2-3 years, instead of using the the recommended intervals. Wanna put me in charge of your car maintenance??

 

[tbuelna]

The only safe approach to ensure that threaded fasteners are safe for re-use is a controlled and documented installation/maintenance/removal process. Unless you have reliable, documented evidence of the service history of the fastener, how would you know whether it is suitable for re-use?

Fasteners are cheap. Failures are expensive.