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RE: RE: Welding on bolts

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When I read about "torquing" bolts it is like drilling a molar without any
pain killer.  Lock washers should never be used on high strength bolts.  And
torquing is no way to tension a bolt.  Torque wrenches are only allowed to
be used as an arbitration device in tensioning.  Even as an arbitration
device its use is suspect.

What we are trying to do is provide a tension in the bolt.  The methods of
bolt tensioning are pretty straight forward in the AISC RCSC Spec.  There is
to be no compressible materials within the bolt grip.  The only exception is
the load indicating washer which requires extensive testing.

Generally there is no need to provide any additional locking mechanism to
properly tensioned high strength bolts.  Often times the tensioning process
deforms the threads in the tensioning process.  That is why the re-use
provisions are in the RCSC Spec.

As previously stated, the heat effected zone on a tack weld is pretty
limited to about the thickness of the weld.  But if you have a bad welder
and a long arc, you could heat more of the length of the bolt enough to
degrade the alloy material properties.  On a case by case basis, it might
not be a problem, but it is just not a good idea.

Regards,
Harold O. Sprague


> -----Original Message-----
> From:	H Boge [SMTP:HBOGE(--nospam--at)boge-boge.com]
> Sent:	Friday, March 30, 2001 9:55 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Re: RE: Welding on bolts
> 
> Damaging the threads is a standard practice.  What about Lock washers,
> I've received some complaints that when iron workers torque bolts they
> aren't sure if they are torquing up agianst the steel or the lock washer
> - any comments
> 
> I would not recommend welding on bolts either, but if you weld below the
> nut and damage the heat propeties of the bolt below the nut, does this
> really matter for the connection.  The forces are transferred higher up
> the bolt.  Or does the heat transfer extend throught the entire bolt.
> 
> >>> "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com> 03/30/01 09:26AM >>>
> Mechanical deformation of threads is very low tech.  
> 1.	Tighten the bolt to whatever is required
> 2.	Place a the pointed end of a bull pin (AKA drift pin depending on
> regional iron worker vernacular) at the junction between the bolt threads
> and the nut
> 3.	Strike the bull pin with a 3 or 4 pound hammer as many times as
> required to crimp the thread flights.  It usually takes only one whack.
> 
> Different iron workers have varying techniques, but the result is the
> same.
> The thread flights of the nut are mechanically crimped and locked to the
> thread flights of the bolt.
> 
> Regards,
> Harold O. Sprague 
> former iron worker,
> inventor of bolt mechanical thread deformation,
> inventor of the back gouge access hole (as opposed to weld access hole),
> inventor of the wheel,
> inventor of "prior art",
> etc.  (send royalties... grin)
> 
> 
> > -----Original Message-----
> > From:	Boh Jaw Woei [SMTP:boh.jaw.woei(--nospam--at)pwdcorp.com.sg] 
> > Sent:	Friday, March 30, 2001 8:21 AM
> > To:	'Sprague, Harold O. '; ''seaint(--nospam--at)seaint.org' '
> > Subject:	RE: Welding on bolts
> > 
> >  Thanks! This advice will help a great deal. May you also advise what we
> > mean by mechanical deformation of the treads.
> > 
> > jw
> > 
> > -----Original Message-----
> > From: Sprague, Harold O.
> > To: 'seaint(--nospam--at)seaint.org' 
> > Sent: 3/30/01 10:09 PM
> > Subject: RE: Welding on bolts
> > 
> > Welding bolts is a bad practice.  High strength bolts are often quenched
> > and
> > tempered and often high carbon.  Even if you account for welding high
> > carbon
> > steel you can impair the strength of the material because the material
> > is
> > quenched and tempered (heat treated).
> > 
> > Depending on the location of the weld on the bolt there is a risk of
> > reduced
> > strength, lower ductility, less resistance to fatigue, and less
> > resistance
> > to impact.
> > 
> > That said, if it is a small tack weld just to prevent nut rotation, the
> > heat
> > effected zone is very localized and on the opposite side of the highly
> > stressed thread engagement area.  High strength bolt thread engagement
> > lengths are designed to fully develop the bolt and the stress is
> > concentrated in the first few flights of the thread engagement.
> > 
> > If the bolt is a low carbon steel with no heat treatment, welding should
> > be
> > less of a problem.  
> > 
> > Again it is not a good practice.  Mechanical deformation of the threads
> > is a
> > much less risky method to prevent nut rotation.
> > 
> > Regards,
> > Harold O. Sprague
> > 
> > 
> > > -----Original Message-----
> > > From:	Boh Jaw Woei [SMTP:boh.jaw.woei(--nospam--at)pwdcorp.com.sg] 
> > > Sent:	Thursday, March 29, 2001 10:27 PM
> > > To:	'seaint(--nospam--at)seaint.org' 
> > > Subject:	Welding on bolts
> > > 
> > > Need to know the effects of welding on bolts, both high and low carbon
> > > contents. Any comments or advice will be appreciated.
> > > 
> > > sgdon
> > > 
> > 
> 
>