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RE: Welding Tubes

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This has always been a problem.  

Also consider welding the bearing plates of a bar joist to a heavy
structural steel wide flange beam.  Iron workers in the field never preheat
for this.  They start their arc (a large arc with no deposition, a lot of
heat, and a lot of spatter) on the heavy member in an attempt to preheat.
Then they shorten the arc and work the arc over to the lighter gage
material.  It is not exactly AWS, but it gets it done.  

In the shop, the rods are fast fill, and don't work as well (a lot more
spatter with a long arc).  And the shop guys are not accustomed to anything
other than a position weld.  Preheating gets the best looking weld.  But a
good welder can probably put down a 5/16" single pass fillet in the shop
without preheating.

Wait a minute!  You are in Florida.  The preheat for a low hydrogen rod is
only 50 degrees F for A36 from plate thicknesses from 3/4" to 1/1/2".  Is it
less than 50 degrees in Gulf Breeze?

Regards,
Harold Sprague

> -----Original Message-----
> From:	Fountain Conner [SMTP:fconner(--nospam--at)pcola.gulf.net]
> Sent:	Friday, February 11, 2000 9:35 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Re: Welding Tubes
> 
> Along this same line, how do you deal with *minimum welds*?
> 
> Yesterday I was faced with welding a 1/4" tube (12"x24" built-up section)
> to a 1" baseplate.  AISC *minimum weld* is 5/16" (thicker than the tube). 
> Structurally, 1/16" weld would be enough (if you could make one).  
> 
> To get proper weld penetration into the base plate, you'll burn up the
> tube.
> 
> Fortunately, this is not a "production" situation (only two columns, sized
> for geometry, not strength).  The shop will preheat the base plates so we
> can make a decent weld.
> 
> 'Any other ideas?
> 
> Thanx,
> 
> Fountain E. Conner, P.E.
> Gulf Breeze, Fl. 32561
>