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[MW:7921] MW: 7874- PWHT

By Materials & Welding

Redouane,

In B-31.3 code,for branch connection PWHT criteria is as follows:-

331.1.3 Governing Thickness for Heat Treatment. When components are joined by welding, the thickness to be used in applying the heat treatment provisions of Table 331.1.1 shall be that of the thicker component measured at the joint, except as follows:

(a) In the case of branch connections,  whether an integral part of a branch fitting or attached as a reinforcing pad or saddle, heat treatment is required, as follows:-

(1)Heat treatment is not required  for P-No. 1 materials when weld throat thickness is 16 mm (5⁄8 in.) or less, regardless of base metal thickness.

(2) not required for P-No. 3, 4, 5, or 10A materials when weld throat thickness is 13 mm (1⁄2 in.) or less, regardless of base metal thickness, provided that not less than the recommended preheat is applied, and the specified minimum tensile strength of the base metal is less than 490 MPa (71 ksi).

For weldolet, the weld joint would be a groove and fillet weld. Hence the throat thickness is important. Assuming the material of construction is Carbon Steel,if the throat thickness exceed the above , PWHT is necessary.

 
Thanks.


Pradip Goswami,P.Eng.
Welding & Metallurgical Specialist & Consultant
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Brl Pp
Sent: Wednesday, October 27, 2010 7:04 AM
To: Materials & Welding
Subject: [MW:7874] PWHT

Good morning,

Please see below the data of piping line for erection:

- Diameter of pipe: 48"

- Produced: liquefied natural gas.

- Piping class: D41A

- Piping thickness: 38mm.

- Weldolet thickness : 15mm.

- Design code: ASME B31. 3. 2008 Edition.

- PWHT: By code.

According to your experience, for this case we use the PWHT?

If yes, please share your experience. Thanks in advance.

My best regards.


Redouane (Project engineer)
Algeria

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