FW: 8050] Weld Joint Preparation for Thk=146mm

[pgos...@sympatico.ca]

Hi Shadab,

 

If you do not have the machnning capacity for Narrow Gap joints ( 2-5 deg included angle), then this joint should be fine. I would like to suggst 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 adouble 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 heas and powe are equipped with Tandem or Twin Arc SAW, one can make up for the fabriction 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,

pgos...@quickclic.net

 

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Shadab Alam Ansari
Sent: Wednesday, November 03, 2010 6:05 AM
To: material...@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.

 

 

 

Waiting for reply.

 

Thanks!!!!!!!!

 

Regards

Shadab

Welding Engineer

 

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[Shadab Alam Ansari]

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

 

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: ans...@ghi.com.sa

Web: "www.ghi.com.sa"

 

Save paper, don't print any emails unnecessarily. Let's save environment for future generation....

 

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of pgos...@sympatico.ca
Sent: Sunday, November 14, 2010 12:19 AM
To: material...@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,

pgos...@quickclic.net

 

 

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Shadab Alam Ansari
Sent: Wednesday, November 03, 2010 6:05 AM
To: material...@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

 

[Vanchinath S.A.]

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

[pgoswami]

Hello Shadab,

 

You will find the attached article quite useful for general knowledge on Narrow gap SAW. The typical specialties of this process:-

• 2-5 deg total included  bevel angle  NGSAW. 10-20 deg total included angle quasi narrow gap.
• My experience tells it's good to start with quasi narrow gap details then to move real narrow gap weld. This gives the necessary confidence to welders. If NGSAW bevel and welding is a regular feature in your shop then welders would not need any quasi narrow gap to  develop the confidence.
• Good Wire and Flux combination is  a must for NGSAW. More than the wire it's the flux. Generally all basic high quality SAW fluxes. such as OK-10.62, OP-41TT or UV421TT/421TTR/421TTRC  or Kobelco PF-200 are proven fluxes for NGSAW. While selecting a flux wire combination consumable manufacturers' opinion also may considered.
• NGSAW would require more  careful monitoring of welding parameters.Defects, removal & repair could be painstaking and costly. Often a defect or a suspected defect shall be removed/ repaired before proceeding for the rest of the weld.
• Common techniques are 1-2-3 pass/layer technique. 2 pass /layer technique is more tolerant to defects and offer more flexibility to welders. Typically the fillet shall be flat and bead shall be thin typically ( form factor less than 3 ). Thick and bulky beads (often termed as peaky beads) could cause solidification cracks due to shape/form factors.

I hope the attached information would provide  you further guidelines.

 

Thanks

 

Pradip Goswami,P.Eng. IWE.

Welding & Metallurgical Specialist & Consultant

Email-pgoswami@sympatico.ca,

pgos...@quickclic.net

 

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Vanchinath S.A.
Sent: Friday, November 19, 2010 10:29 AM
To: material...@googlegroups.com
Subject: Re: [MW:8327] RE: 8242] FW: 8050] Weld Joint Preparation for Thk=146mm

[Prakash Hegde]

We have tried the NGW with single bevel  by keeping 3 degree included angle with 10R at root   for thk up to 180 mm w/o any problem for CS and LAS material

Regards

 

Hegde P.B.

---

From: Vanchinath S.A. <vanch...@gmail.com>
To: material...@googlegroups.com
Sent: Fri, 19 November, 2010 8:59:27 PM
Subject: Re: [MW:8327] RE: 8242] FW: 8050] Weld Joint Preparation for Thk=146mm

[Shadab Alam Ansari]

Dear Mr. hedge,

If you are doing the NGW on 180mm Thk, then it will require some special nozzles to go deep inside the groove.

 

 

Best regards,

 

Shadab Alam Ansari

Welding Engineer

 

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: ans...@ghi.com.sa

Web: "www.ghi.com.sa"

 

Save paper, don't print any emails unnecessarily. Let's save environment for future generation....

 

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Prakash Hegde

Sent: Saturday, November 20, 2010 3:01 PM
To: material...@googlegroups.com