Re: flange stud bolt replacement criteria.

I have a reprint of a great article in the Sep/Oct '96 issue of "American Fastener Journal". I've looked for it on the internet but it doesn't seem to be available anywhere. It's titled: "When is a Bolt Suitable for Reuse?". The author is Dr. Joe Greenslade. He is described as "President of Greenslade & Co. located in Rockford, ILL. His firm specializes in providing manufacturing tooling and inspection equipment to suppliers of bolts, screws, rivets, and nuts throughout the world". I'll quote the pertinent passages:

"...the question arises as to whether...bolts are suitable for reuse or not. The answer to this question is: when a bolt has not been stressed past its yield point it can be reused. This answer brings to mind two more logical questions: what does it mean that a bolt has been stressed past its yield point? A bolts yield point has been exceeded when the bolt does not return to its original length when the assembly stress is removed from it...How can one easily determine if a bolt has yielded? Simply screw a nut on the previously used bolts threads to the head on a fully threaded bolt or to the thread run-out on a bolt with a full diameter body. If a nut will not screw on the entire bolt thread length, the bolt has yielded and it is not safe to reuse."

• Original Message -----
  From: Steve McKenzie<mailto:Mechproj@xtra.co.nz>
  To: <a href="/group/PipingDesign/post?postID=DrL3b0_a2ZoAEz1zj33JRo9F76T8e8Q_hQf3X6uzXuNb4Ihd6LoNIlYGS-kf_ENZxwGmC3mKxSs0xlW8Gyq_TxPB7qA8Cw">PipingDesign@yahoogroups.com</a><mailto:<a href="/group/PipingDesign/post?postID=DrL3b0_a2ZoAEz1zj33JRo9F76T8e8Q_hQf3X6uzXuNb4Ihd6LoNIlYGS-kf_ENZxwGmC3mKxSs0xlW8Gyq_TxPB7qA8Cw">PipingDesign@yahoogroups.com</a>>
  Sent: Wednesday, May 04, 2005 6:45 AM
  Subject: [PipingDesign] flange stud bolt replacement criteria.
  

O Learned Ones

I do some work at a plant which has many flange stud bolt connections;
some of which are dismantled quarterly. Short cycle fatigue is not an
issue during operation, but perhaps there is a need to replace stud
bolts after a certain number of retensionings. At present studs are
replaced only if they show visual signs of distress, but this approach
seems somewhat arbitrary. Flange classes are 150# thru 600# studs are
typically low alloy steel with a few exotics thrown in and temperatures
are moderate; up to 250C.
I could revert to first principles, calculate bolt stresses and work
out fatigue life, but feel countless people will have done this before.

Does anyone have any references to standard testing/rejection criteria
for stud bolts? If so a reference would be appreciated.

Cheers

Steve

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[Non-text portions of this message have been removed] Received on Sun May 08 12:44:00 2005