PWHT of tank shell plates as per API 650

[Manav Malhotra]

Dear Members,

 

We have crude and petroleum tanks in which shell plates thickness vary from 8 mm to 45 mm and the tanks are constructed by our contarctors. We just want to be sure whether PWHT has to be carried out or not. Our contrcator says as per API 650 there will be no PWHT of shell plates. I also refered API 650 but couldnt find any thing about pwht of shell plates. Cab any one help me out on this issues, in case pwht is to be carried out for shell plates, kindly provide the reference clause no from API 650.

 

Regards,

 

[pgoswami]

Mr Malhotra,

 

Please refer the following clause of API 650 regarding PWHT, for Gr I,II,III,IIIA steel,Table 4-4a illustrates the grouping, which mostly applies to Carbon Steel.

 

If the steel used falls in any one of the above group and the weld exceeds 25 mm (1 inch) in thickness ,PWHT would be required as per clause 5.7.4., 5.7.4.3

 

Thanks.

 

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgos...@quickclic.net

5.7.4 Thermal Stress Relief: When the shell material is Group I, II, III, or IIIA, all opening connections NPS 12 or larger in nominal diameter in a shell plate or thickened insert plate more than 25 mm (1 in.) thick shall be prefabricated into the shell plate or thickened insert plate, and the prefabricated assembly shall be thermally stress-relieved within a temperature range of 600°C – 650°C (1100°F – 1200°F) for 1 hour per 25 mm (1 in.) of thickness prior to installation. The stress-relieving  requirements need not include the flange-to-neck welds or other nozzle-neck and manhole-neck attachments, provided the following conditions are fulfilled:

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Manav Malhotra
Sent: Sunday, March 13, 2011 1:08 PM
To: material...@googlegroups.com
Subject: [MW:10320] PWHT of tank shell plates as per API 650

Dear Members,

 

We have crude and petroleum tanks in which shell plates thickness vary from 8 mm to 45 mm and the tanks are constructed by our contarctors. We just want to be sure whether PWHT has to be carried out or not. Our contrcator says as per API 650 there will be no PWHT of shell plates. I also refered API 650 but couldnt find any thing about pwht of shell plates. Cab any one help me out on this issues, in case pwht is to be carried out for shell plates, kindly provide the reference clause no from API 650.

 

Regards,

 

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[Kathalingam Babu]

Hi

 

API 650 doesn't discuss about the PWHT except cl 5.2.3.5,

 

Actually , the welding procedure has to provide the PWHT requirements.

 

If it is the existing tank , you can refer API653 spec,

 

Thanks & Regards,

 

K. Babu

Singapore

 

 

----- Original Message -----

From: Manav Malhotra

To: material...@googlegroups.com

Sent: Monday, March 14, 2011 1:07 AM

Subject: [MW:10320] PWHT of tank shell plates as per API 650

Dear Members,

 

We have crude and petroleum tanks in which shell plates thickness vary from 8 mm to 45 mm and the tanks are constructed by our contarctors. We just want to be sure whether PWHT has to be carried out or not. Our contrcator says as per API 650 there will be no PWHT of shell plates. I also refered API 650 but couldnt find any thing about pwht of shell plates. Cab any one help me out on this issues, in case pwht is to be carried out for shell plates, kindly provide the reference clause no from API 650.

 

Regards,

 

[Kathalingam Babu]

Hi

 

If i am not wrong the below clause is for the flush type cleanout fittings rather than the shell butt welded plates

 

Thanks & Regards,

 

K. Babu

----- Original Message -----

[vikr...@gmail.com]

As per API clause 4.2.2 e) ASTM A516M Grades 380, 415, 450, 485/A516, Grades 55, 60, 65, and 70, for plates to a maximum thickness of

40 mm (1.5 in.) [thickened insert plates and flanges to a maximum thickness of 100 mm (4 in.)].

Maximum thickness is allowed upto 40mm for A516 Gr.70 material, how subcontractor can consider 45mm thickness for Crude tank.

Regards,

Vikram

[Raghuram Bathula]

read next para, you will get the answer.