Friday, November 19, 2010

Re: [MW:8327] RE: 8242] FW: 8050] Weld Joint Preparation for Thk=146mm

For narrow gap welding with single bevel with included angle of 5 degree, there will be radius at the root of the joint  of 6 or 8mm. this will ensure bead width  is greater than depth to avoid solidification cracking problem.
regards
vanchi

On Sun, Nov 14, 2010 at 10:57 AM, Shadab Alam Ansari <ansari@ghi.com.sa> wrote:

Dear Sir,

If we are going for Narrow groove welding with only single bevel and less degree, For SAW welding, there will be solidification cracking problem since the depth to width ratio will not be maintained as 3:1.

Please suggest.

 

Thanking you,

Best regards,

 

Shadab Alam Ansari

Welding Engineer

 

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For Gulf Heavy Industries Co

One of  Al-Bassam Group of Companies

 

Cell Phone No: 00966502090165, Fax No:0096633410105
Telephone No: 0096633400098 (5 Lines) Ext: 232

Email: ansari@ghi.com.sa

Web: "www.ghi.com.sa"

 

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of pgoswami@sympatico.ca
Sent: Sunday, November 14, 2010 12:19 AM
To: materials-welding@googlegroups.com
Subject: [MW:8242] FW: 8050] Weld Joint Preparation for Thk=146mm

 



Hi Shadab,

 

If you do not have the machining capacity for Narrow Gap joints ( 2-5 deg included angle), then this joint should be fine. I would like to suggest some fine points based on my past experiences in  shop welding  for thick walled pressure vessels:-

 

  • Long Seams-Remove the backing strip altogether. Rolling the backing strip to shell contour and making  perfect fit up is quite difficult in double vee weld. Moreover when backing strip gets fused while welding, one has to do immense gouging to remove it completely. Hence a conventional double vee joint, 2/3Vee Outside(45 -50 deg included angle) and 1/3 Vee inside (55-60 deg included angle) may  be a good option. Such joints may be prepared by high power gas cutting  and grinding. Weld metal deposition may be more, however if welding has and power are equipped with Tandem or Twin Arc SAW, one can make up for the fabrication time.

 

 

  • For C Seams-- you may adopt a quasi narrow gap bevel to start with. A sample bevel is  shown in the attachment. The included angle may be chosen to be anything between 10-20 deg and the edge preparation be done with gas cut followed by machinning.Placing a backing strip would be the joint fit up easy.

 

For welding of thickwalled plates, Narrow Gap welding(2-5 de included angle) is the best choice, due to less distortion, better weld and HAZ properties,considerabe savings on weld metal, fabrication time etc.But without good machning facilities,this process ia almost difficult to implement.An alternative may be edge prep and rolling in outside shops, then perfom welding at fabricator's workplace, busometimes thatmay not e a realistic solution.

 

Thanks

 

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

 


From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Shadab Alam Ansari
Sent: Wednesday, November 03, 2010 6:05 AM
To: materials-welding@googlegroups.com
Subject: [MW:8050] Weld Joint Preparation for Thk=146mm

Dear All,

We are having 146mmthk shell welding for P1 material with PWHT & Impact as per ASME SEC-VIII Div.2

Please give me best possible weld configuration. We don't have facility to make J grooves.

Is there any portable machines available in the market to make J grooves on such high thick plates.

I have prepared one sample Bevel edges as attached below.

 

 

 

Error! Filename not specified.

Waiting for reply.

 

Thanks!!!!!!!!

 

Regards

Shadab

Welding Engineer

 


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