Re: Re: Bolting Loose

From: <Christopher>
Date: Tue May 17 2005 - 16:50:00 EDT

On May 17, 2005, at 11:56 AM, alejandroperezposada wrote:

> Is there a posibility in replace the ASTM A-193
> GR B7 stud with a Machine Bolt Grade 8?
why do you think you need to replace the bolt? You shouldn't be guessing about this. First, you *must* use ASME specifications for bolts anyway. Nylock bolts probably won't

What are your bolting calculations telling you about the adequacy of the bolt?
What does the joint look like?
What size are the bolts and how long are they? Is there a gasket involved?
I gather your loads are cyclic. Have you done any calculations to see if the temperature excursions are high enough to relax the preload in the bolt?
What is the temperature and pressure range? How long does it take for the bolts to loosen (in terms of the load cycle time)?
Have you set the preload?
How certain are you that the bolts are tightened properly? Have you checked?

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=xcutzVrNtQ7tY7LLTkM5wqlbNB9KfW8POiJ8CAAaoHGs-ia3h_rOc5V-3mCeAFKEUgd3uEvJ9NGvoRr0ORs">chrisw@skypoint.com</a> | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania

1864)
<a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a> Received on Tue May 17 16:50:00 2005