Friday, June 11, 2010

[MW:5529] FW: 5520] FW: Urgent quarry on filler wire selection and heat treatment after welding


 

Dear Subrata,

 

ER-NiCrMo4 is the correct filler metal for joining Hastelloy C-276 to same and dissimilar welds between P-91 to Hastelloy, C-276. However there could be issues as mentioned below:-

 

1.     Weld joint between P-91 to C-276 involves a gross mismatch in selection of alloys. P-91 primarily is chosen for Creep and high temperature oxidation and sulfidation  resistances in the industry. While C-276 is used for extremely corrosive environments. Where such dissimilar weld would be applicable ? 

 

2.     C-276 base metal and weld metal have the best properties in solution annealed conditions. Prolonged exposure at  P-91 PWHT temperature, i.e. 7800 C could embrittle the alloy, due to formation of intermertallics. There are articles on this.

 

3.     The suggested practice is to butter, P-91, with  ER-NiCrMo4, perform PWHT @ 760-7800 C .subsequently weld with ER-NiCrMo4/C-276 consumables without performing  any more PWHT. This would help to retain the best properties of  C-276 base metals and the matching weld.

 

Thanks.

 

Pradip Goswami,P.Eng.

Welding & Metallurgical Engineer/Specialist

Ontario Power Generation Inc.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

 

 


From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Subrata Das
Sent: Thursday, June 10, 2010 6:54 AM
To: materials-welding@googlegroups.com
Subject: [MW:5520] FW: Urgent quarry on filler wire selection and heat treatment after welding

 

 

 

From: Subrata Das [mailto:sdas@pkgroup.org]
Sent: Tuesday, June 08, 2010 12:11 PM
To: 'materials-welding@googlegroups.com'
Subject: Urgent quarry on filler wire selection and heat treatment after welding

 

Dear All

Can you all please guide me about the following confusion

I have conducted a PQR with base metal as A335 Gr.P91 to SB622 Hastelloy C276 N10276 with PWHT at 780 deg.C by GTAW process(Groove Weld Joint).

Now my job is A182 F91 to SB622 Hastelloy C276 N10276 with GTAW process and groove weld joint.

My quarry is that :

1.       Can I use filler metal as ER-NiCrMo4(SFA-5.14)/F.No.43.

2.       Shall I go for PWHT at 780 deg.C. or not necessary to do PWHT.

3.       Is it necessary to conduct mechanical test after PWHT as the job is a self equipment and not possible to destroy.         

 

Thank you with best regards

Subrata Das

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