Zero gap butt welding

[Muhammed Ibrahim]

Hi Gents,

 

Anybody having experience with zero gap butt welding (V- groove with more root face) with direct SAW in pressure vessels. Is it possible in circular seam?. If possible how much root face should be maintained?.

Thanks & Regards
Muhammed Ibrahim PK

[PB HEGDE]

Hi!

We have been using this practice of zero gap butt joint for shell thk of 12 mm to 20mm , and above 75mm thk joint.

We keep the zero gap with tolerance of  0-1mm and  root face should be of 3-4mm for smaller thk and 5-6mm for thicker shell

To avoid any burn through, we require to increase the speed of weld with lower side current of WPS for root pass. This parameters are require to be established at each place

 

Regards

 

Hegde P.B.

[prashant pansare]

Dear friend, U can refer AWS D 1.1, Section 4 para 4.12.4.1,but it' s for structural ,only u can have idea regarding qualification for narrowest & widest root gap & reqd. sizes also. Regards, Prashant Pansare (IRS)   --- On Fri, 8/5/09, PB HEGDE <hegd...@isgec.com> wrote:

Regards   Hegde P.B.

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[PREM SHANKARDUTT NAUTIYAL]

Hi Friends

Presently I have established zero gap butt welding with direct SAW for following type of joint:
Double V Joint with both equal V, i.e bevel in centre only.Included angle=60degrees(both).
0-0.5mm root gap,1mm root face.
Long seam joint of 50mm thick SA516Gr.70 shells.
SAW wire dia.=3.15mm.
Parameters for root run is most important:430A,28V,T.S=300mm/min.Preheat=150degrees celcius.
Then 430A,30V for subsequent passes.
With these parameters we are able to minimize chipback to a mere depth of 2mm only.
UT=100% clear.
Benefits of zero gap welding:
Less skilled fitter is required for setup.
Productivity increases as setup time is less (no need to maintain rootgap.)
Less distortion due to less shrinkage stresses.
Ovality can be better controlled.

Regards

Prem S Nautiyal
Godrej,Vikhroli,Mumbai.

On Fri, 08 May 2009 12:33:51 +0530 wrote

>Hi!
>
>We have been using this practice of zero gap butt joint for shell thk of 12
>mm to 20mm , and above 75mm thk joint.
>
>We keep the zero gap with tolerance of  0-1mm and  root face should be of
>3-4mm for smaller thk and 5-6mm for thicker shell
>
>To avoid any burn through, we require to increase the speed of weld with
>lower side current of WPS for root pass. This parameters are require to be
>established at each place
>
>
>
>Regards
>
>
>
>Hegde P.B.
>
>
>
>From: material...@googlegroups.com
>[mailto:material...@googlegroups.com] On Behalf Of Muhammed Ibrahim
>Sent: Thursday, May 07, 2009 4:47 PM
>To: material...@googlegroups.com
>Subject: [MW:2122] Zero gap butt welding
>
>
>
>Hi Gents,
>
>
>
>Anybody having experience with zero gap butt welding (V- groove with more
>root face) with direct SAW in pressure vessels. Is it possible in circular
>seam?. If possible how much root face should be maintained?.
>
>Thanks & Regards
>Muhammed Ibrahim PK
>
>
>
>
>>
>

PREM S NAUTIYAL

CELL : 9820313278

[PB HEGDE]

Hi !

For Zero gap . We have successfully tried for mass production

 

15mm thk Shell long seam .

ii) square butt zero gap

iii)4 dia wire

iv)550 A 30V 22 inch/min speed ( One has to establish the parameter before start)

vii) Weld one side Say from inside This will penetrate half way

viii) W/o back chipping weld from otherside with 600A current and of 22inch/min speed

You get good weld w/o back gouging  With RT ok

 

This is for your inf please by the way you are from which plant in Godrej. As I am ex Godrej  Welding head PED

 

Regards

 

Hegde p.B.

 

From: PREM SHANKARDUTT NAUTI

AL [mailto:prem_n...@rediffmail.com]
Sent: Saturday, May 09, 2009 2:09 PM
To: hegd...@isgec.com
Cc: material...@googlegroups.com
Subject: Re: [MW:2126] RE: 2122] Zero gap butt welding

[Muhammed Ibrahim]

Hi gents,

 

Thank you for spending your valuable time for this discussion thread.

Awaiting more info.

 

Regards,

Muhammed Ibrahim

 

2009/5/11 PB HEGDE <hegd...@isgec.com>

Hi !

For Zero gap . We have successfully tried for mass production

 

15mm thk Shell long seam .

ii) square butt zero gap

iii)4 dia wire

iv)550 A 30V 22 inch/min speed ( One has to establish the parameter before start)

vii) Weld one side Say from inside This will penetrate half way

viii) W/o back chipping weld from otherside with 600A current and of 22inch/min speed

You get good weld w/o back gouging  With RT ok

 

This is for your inf please by the way you are from which plant in Godrej. As I am ex Godrej  Welding head PED

 

Regards

 

Hegde p.B.

 

From: PREM SHANKARDUTT NAUTI

AL [mailto:prem_n...@rediffmail.com]
Sent: Saturday, May 09, 2009 2:09 PM
To: hegd...@isgec.com
Cc: material...@googlegroups.com

Subject: Re: [MW:2126] RE: 2122] Zero gap butt welding

--

[Gurmeet singh mehta]

Hi,

It is possible with welding zero gap for circular seams also.

The Root face shall be anywere between 12- 17 mm.

But please note if Full penetration joint is required you may need to caryy out back gouge also.

regards

Gurmeet singh

[MAHANTESH LONI]

Basically in zerro gap butt welding you need to use higher currents (i.e 550-650 Amps) for a root face of 8-10mm. You need to weld from both sides, its mandatory. Also check is their any impact requirement, if so, you need to check heat input.

 

Regards

Loni