[MW:6626] RE: 6623] Manufacturer PQR Test results of 25 Cr 35 Ni to SA 479 TYP 304H - furnace tubes

Hi Mr Kareem,

 

Would you provide more details on:-

• the 25 Cr 35 Ni alloy grade or ASTM specifications.
• What welding process including the welding consumables were used ?

 

This alloy has very limited weldability, partly because it's cast and contains high "C". However the sample data sheet shows that this material could be manufactured to a reasonably sound weldable grade.

 

The elongation noted in the PQR is very low. Though Sec-IX, QW-466.1 allow the following clause to be exercised (see below), however you need to explore all the pros and cons before accepting or rejecting the PQR results.

 

Appreciating your inputs.

 

Thanks.

 

Pradip Goswami,P.Eng.

Welding & Metallurgical Engineer/Specialist

Ontario Power Generation Inc.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

 

(e) For materials with less than 3% elongation, a macro-etch specimen shall be used in lieu of bend test at each bend test location. Acceptance criteria shall be in accordance with QW-183(a).

 

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Mohamed Abdul Kareem
Sent: Sunday, August 22, 2010 5:20 AM
To: materials-welding@googlegroups.com
Subject: [MW:6623] Manufacturer PQR Test results of 25 Cr 35 Ni to SA 479 TYP 304H - furnace tubes

Hi, Manufacturer PQR Test results of 25 Cr 35 Ni to SA 479 TYP 304H - furnace tubes   Tensile test of the 13 mm thick specimen results in 2.67 % & 3.7 % elongation   Bend test (As per ASME IX) failed at the HAZ. Manufacturer has followed ASTM A 488 "Standard specifications for steel castings, Welding, Qualification of procedures and personnel" to qualify the procedure.   Question   1.       Is the PQR qualified if QW-466.19 [General notes (E)] is followed?. "QW-466.19 - For material with less than 3 % elongation, a macro etch specimen shall be used in lieu of bend test at each bend location. Acceptance criteria shall be in accordance with QW-183(a)".   2.       Can ASTM A 488-8.2.4 be followed to qualify a procedure?   "ASTM A 488-8.2.4 – Where the ductility of the parent metal is such as to render it incapable of meeting the bend test requirements, the bend test shall be conducted in the following manner: A bend bar comprised of parent metal heat treated to the ductility & strength requirements of the applicable specifications shall be bent to failure. The side bend specimen shall be then capable of being bent to within 5° of the angle thus determined."   Regards, kareem

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