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RE: Welding on bolts

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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.

Harold O. Sprague

> -----Original Message-----
> From:	Boh Jaw Woei [SMTP:boh.jaw.woei(--nospam--at)]
> Sent:	Thursday, March 29, 2001 10:27 PM
> To:	'seaint(--nospam--at)'
> 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