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Re: [MW:30093] RE: 29965] Impact test fails FCAW process

By Materials & Welding
Yes I agree with Goswami sir.
It is not easy to qualify with impact with low temperature.
Need to control & record minor data for conclusion of any results,including position of welding, Groove geometry, no of passes, heat input & deposition of each pass,gas composition/mixtures,& finally manufacturer/ brand.

Please share.
CLV

On Wed, Aug 21, 2019 at 2:42 AM PGoswami <pgoswami@quickclic.net> wrote:

Hi,

 

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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