Hello Rohit
As you are getting blowholes while welding the second side of the joint, then i suggest that you personally ensure that after chipback grinding, the LPT is clear.
After that with proper baked flux, preheating as per WPS carry out welding from other side.
Regards
Prem Nautiyal
Godrej, Mumbai.
On Tue, 21 Jul 2009 08:00:58 +0530 wrote
>Sir,
>This is to inform you that we are using two electrode SAW process.
>Thanks,
>Rohit Rawat,
>Asst.Engg.(QA)
>
>--- On Sat, 18/7/09, welding_engr_rich@charter.net
>
>
>From: welding_engr_rich@charter.net
>Subject: [MW:2709] Re: blow holes in double side welding in H-Beam SAW welding
>To: materials-welding@googlegroups.com
>Date: Saturday, 18 July, 2009, 6:26 PM
>
>
>
>I am assuming that you are using the single electrode SAW process.
>Typically blowholes on the second side are a result of flux being trapped
>during the root pass on the first side boiling and escaping through the
>molten metal of the second side weld. After the first side is done look
>carefully at the send side weld prep, look for flux trapped in the root
>area,
>
>Wviness control you could try additional preheat this might help. Contact
>Tipmate http://tipmateusa.com/index.html their nozzle extensions might help
>the waviness problem with a possible increase in production rates.
>
>Best regards,
>Richard Beldyk PhD, PE
>AWS CWEng
>ASNT NDT Level III
>
>Original Message:
>-----------------
>From: raw rohit30584@gmail.com
>Date: Fri, 17 Jul 2009 22:31:52 -0700 (PDT)
>To: materials-welding@googlegroups.com
>Subject: [MW:2702] blow holes in double side welding in H-Beam SAW welding
>
>
>
>Hi everyone out there,
>I am presently working in kirby building systems . we do PEB
>fabrication .we use material ASTM A572 typ1 gr50 .the p[roblem is when
>we do doubl;e side welding, blow holes occur in second side . what is
>the basic reason .allso waviness occurs in flanges of thickness 6mm
>and less,
>thanks,
>rohit rawat
>QA(quality assurance)
>
>
>
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