Also, good bridges tend to fall down every now and then even if they are not inspected regularly (anyone want to comment: I think there's a perfect example here in Quebec.)
Paul
> >Now my query is whether the
> >torquing values will be same for carbon steel ,alloy steel, & SS bolts
or
> >can we use same torquing values for different material bolts like one of
> >A193 B8 & other of A453 gr 660c.
> No. As you pointed out the torque values are based on yield strength, and
> the yield strength differs for different materials. Be careful lifting
> torques from catalogs--don't apply them to other manufacturers fasteners
> and follw the lubrication instructions carefully. Torques will vary a
> great deal depending on the thread lubricant and the technique used. The
> required torque will also depend on the preload value actually needed to
> maintain a seal. The high torques needed for seating metal ring gaskets
> withh crush softer materials.
>
> >Also normally what torquing values are supplied in catalogues are for
cold
> >bolting , what should be the torquing values for hot bolting ?
> Depends on the temperature. You don't really need an empirical
> relationship--estimate the loss in pre-load due to differential thermal
> expansion and increase the torque to account for the loss. Machinery's
> Handbook has a very good section on bolting and bolt torques and how to
> figure what you need.
Received on Fri Oct 04 15:33:00 2002
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