Hi, If you application invloves welding of pipes (Where back chipping is not possible), there are two options for welding the root pass. 1. Use electrodes E 6010 or E 7010 (cellulosic Electrodes) or E 7016-1 for non critical lines (e.g., lines other than compressor suction / inlet lines). 2. Use STT (Surface Tension Transfer) Process for root pass, it is similar to GMAW short circuit transfer mode of metal transfer. You'll need to properly set the welding parameters to avoid any LOF, but once your welders are well trained, you can really see the productivity. Please note that some clients still have a restriction on using this process. If you application involves fabrication of pressure vessels, where you have enough access for back chipping the root pass, and you wish not to do so, then SAW is a good option. The joint preparation shall be such that the root face or the land should be long enough to prevent any burn though when welding the root pass, in addition to that you'll have to have tight butt joint (i.e.,) no root gap at all. After completion of one side, weld the other side (without back chipping) with SAW process, you parameters should be such that you have good cross penetration (engulfing the lan or root face) thus giving you a full penetration butt joint without the need for back chipping. Hope this helps. Regards, Praveen Alavandar
--- On Thu, 6/30/11, rajeev arora <rajeevarora007@gmail.com> wrote:
From: rajeev arora <rajeevarora007@gmail.com>
Subject: Re: [MW:11538] GMAW application restriction
To: materials-welding@googlegroups.com
Date: Thursday, June 30, 2011, 4:14 PM
there is electrode , which is having good penetration power i.e. E7010 , get check with the manufacture On 30 June 2011 17:39, Maulik Thakkar <mlkthakkar2@gmail.com> wrote: Dear,, With out chip back. I want the process which can replace slower GTAW for single sided full penetration joint with out any chip back
On Thu, Jun 30, 2011 at 3:55 PM, rajeev arora <rajeevarora007@gmail.com> wrote: SMAW On 30 June 2011 17:05, Maulik Thakkar <mlkthakkar2@gmail.com> wrote: Is there any option of GTAW for root run to be carried out in pressure vessel welding? On Thu, Jun 30, 2011 at 2:20 PM, AVA <ava.ssg@gmail.com> wrote: There is no limitation for GMAW in ASME code. But pay attention that some of gas cavities made in weld metal that are acceptable according to codes, but it's make may risk for hydrogen induce. Then this process is commonly used for structural equipment's, not in pressure parts. Regards A.V. From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Dinesh Somwanshi
Sent: Thursday, June 30, 2011 1:06 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:11528] GMAW application restriction generally GMAW is used for the filling & capping only.generally the amout of heat produced in this process also there will be chances of lack of fusion at the edges ( fusion boundaries ) the torch cup also makes sometimes for welding in the joint.But this process limited to only low pressure . You can follow with the s maw root & hot ,followed by remaining g maw .
regards
dinesh Why GMAW is not widely used for single sided full penetration joints (with out chip back) for pressure vessel industrial applications? Is there any problem regarding to penetraiton or lack of fusion? I am confusing. Request you to give technical answer. --
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--
Regards, Maulik H. Thakkar Larsen & Toubro, Hazira
--
Regards,
Rajeev Arora 0066-854490697 0066-818706419 --
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Regards, Maulik H. Thakkar Larsen & Toubro, Hazira
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Regards,
Rajeev Arora
0066-854490697
0066-818706419
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