Please see the attached, info on typical FCAW consumable conforming to AWS E71 T12 CJ specifications. Qualifying PQR with FCAW process on 70mm thk plates with PWHT and with impact @-46 Deg C is not easy. Following areas should need attention:-
· Impact values of the consumable, qualification position , 1G or 3G?
· If required ask the consumable manufacturer for impact results in 3G position.
· Your coupon passed in 2G, that's due to the stringer bead technique and lower heat input, what were the recorded heat input??
· Any data on results of the similar product with PWHT(ask consumable manufacturer).
· In order to have a good and consistent impact 1.2.-1.4% Mn or more would be desirable. However in case of hardness restrictions, Manganese have to be restricted.
· Last of shielding gas, for consistent -46 Deg C impact on 70mm thk coupons, use of mixed gas, 80/20 Argon+CO2 or better(90/10). Would be advisable.
Thanks.
P.Goswami.P.Eng, IWE.
Independent & Consulting Welding & Metallurgical Specialist
Linkedin: https://www.linkedin.com/in/pradip-goswami-2999855/
Email:pgoswami@quickclic.net,pradip.goswami@gmail.com
Cell/Whasapp:1-905-9793232
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of chakotevishal47@gmail.com
Sent: August 18, 2019 12:38 PM
To: Materials & Welding <materials-welding@googlegroups.com>
Subject: [MW:29965] Impact test fails FCAW process
Dear experts,
We have carried out FCAW WPQR with PWHT. Welding consumable is E71 T12 CJ. Below are the conditions
Test coupon thk- 70 mm
Parent material- S355 G8+N
Process- FcAW
Welding consumable- E71T-12CJ
PWHT Temp- 580 deg C
Soaking time - 280 minutes
Impact test temp- minus 40 deg C
Heat input range (root)- 1.0-1.6 KJ/mm
Heat input range (cap)- 1.0-1.4 KJ/mm
Thermal efficiency- 0.8
Welding position-3G
The above welding consumable is recommended for PWHT.
The impact values are too low at root as well as cap.
Energy values- 16,15,25 J (root)
Energy values- 30,30,31 J (cap)
Can you please focus on impact values failure reasons?
Even if keeping low heat inputs the test has failed.
What could be the possible reasons of failure?
And with the same conditions WPQR passed with 2G position.
Please focus on possible reasons.
Regards,
Vishal
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