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RE: HAS Weld Symbol

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The normal arc stud welding process for headed studs uses an automatic process employing a direct current and holds the stud back slightly from the steel.  The arc generates heat melting the steel and stud base.  The stud is then plunged into the molten steel pool.  The arc is protected by a ceramic ferrule. 
This is a link to a good chart:
http://www.mwsco.com/kb/articles/WeldSymbolsProof.pdf
 
The AWS has a well written procedure for stud welding.  Fillet welding is allowed and most studs of which I am aware have a carbon equivilence that allows normal shielded metal arc welding.  Interestingly, if you choose to fillet weld a stud, you must remove the dimple on the end of most studs, because the stud must be placed flush against the steel work surface.  It is all covered in AWS D1.1 Chapter 7. 
 
There is a lot of confusion about what the EOR contract drawings need to show vs. what should be shown on shop drawings.  Example: The EOR should show CJP, but the shop drawings should show the specific process prequalified symbol for the CJP.  It is not the same symbol, but we engineers routinely allow it on the shop drawings.  (I drive detailers nuts.)
 
A stud weld is totally addressed in the AWS including a fillet weld.  The EOR contract drawings need to only show that is an arc stud weld (ASW).  However, the shop drawings should indicate what process is to be used.  Generally an automatic stud gun will be used.  If the fabricator or erector chooses to use a fillet weld, it should be shown appropriately.  The size is per AWS D1.1 Table 7.2. 
 
The contract drawings need to show the stud size and number.  The general notes or specifications will indicate that AWS D1.1 is required.  Once an ASW is indicated in section or plan, the procedure and size and testing is dictated per AWS D1.1. 
 
Showing a fillet weld all around technically ties a detailer's hands and may be wrong.  It is best to just show an ASW and let the shop decide if he is going to use an automated arc spot weld or a fillet weld.  A fillet weld will require grinding off all the dimples.  Whatever process is used, it will require testing.  Again that is all specified in Chapter 7. 
 
An ASW using a stud gun requires a very large generator and will require some set-up time.  If there are only a few studs, the detailer may elect to use a fillet weld.  If there are a lot of studs, he will use a generator and a stud gun and use an ASW. 

Regards,
Harold Sprague



From: jrgrill(--nospam--at)cableone.net
To: seaint(--nospam--at)seaint.org
Subject: HAS Weld Symbol
Date: Tue, 6 May 2008 21:42:07 -0700

I was skimming through “Detailing for Steel Construction” second edition (AISC, NSD) book today.  On page 4-34 under “Stud Welds” there is a word description for the weld symbol for welding studs by a stud-welding gun.  It says a circle containing an “X” lying only on the arrow side with the stud size located to the left of the circle, pitch to the right and the number of studs in parentheses below the circle.  I have the stud size figured out, the pitch is the spacing?  But why list the number of studs, or for that matter the spacing, if that information is shown elsewhere such as on the framing plan.  Or, am I confused?  It also refers to figure 4-24bb.  When I go to figure 4-24bb the symbol there looks nothing like the word description.  It shows a butt weld with “SW” in the note location at the end of the symbol.

 

Are there any steel detailers out there that can clarify this for me.  I have seen on many standard details on structural drawings studs being welded with the weld symbol being a fillet weld “all around” with a fillet size given.  Is the fillet weld that I have seen appropriate? And, if so, what size of fillet size should be listed for the different stud diameters?

 

Thanks,

Joe Grill



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