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Up Topic Welding Industry / Technical Discussions / Effectiveness of FCAW
- - By fakhmed Date 08-12-2005 05:46
Hello every body,

For butt welding of material A283GrD thickness 22mm, we use FCAW process with E71T1-MJ filler metal with gas 20%CO2+80%Argon. UT is used for weld inspection and defects found are up to 3%.
Based on what we heard about this process, I have a doubt about its adequacy even if the UT results are satisfactory. Can somebody help me to know about the risk of this process against quality and if any failure can occure for pressurased items in service.

Thank you
Parent - - By Bill Mc (**) Date 08-12-2005 13:08
Can you tell us what kind of weld defects are you seeing?
Parent - - By fakhmed Date 08-12-2005 13:22
Lack of fusion or any other defect which gives poor mechanical propreties even if no indication is identified by NDE methods.
Parent - - By CHGuilford (****) Date 08-12-2005 22:02
I have conducted many PQR test using FCAW E71T-1 on A588 and A572 steels, per the AWS D1.5 fracture control plan. Test specimens were per AWS Fuigure 5.1 (Reduced section tensile, all weld metal tensile, side bends, CVN, macroetch, and chemical analyses.) Almost every test has passed; those that didn't were the result of something the welder made a mistake on. We have used FCAW for everything from API 650 tanks, to bridge members, to structural steel for many years.

Based on that, I have to say that FCAW is certainly capable of producing good welds. You do have to be careful in that a lot of poor welding can be done quickly with just a pull of the trigger. And heat input is very important.
But I suggest that you conduct your own PQR testing so you can check the mechanical properties yourself. I think you might find your problems could be solved with additional welder training and testing, and quality inspection before, during, and after welding.

Chet Guilford
Parent - By labtechy (*) Date 08-19-2005 15:50
I'll agree with you here. FCAW is definetly capable of producing good welds. I test them in our lab and don't see a high rate of failure. Generally any process we check, test or inspect, that fails is a result of the welder.
Parent - - By jiweiming (**) Date 09-03-2005 06:22
so do you have used FCAW process in pressure vessels manufacturing? I mean choose this process to weld longitudinal and circumferencial seam.many thanks.
Parent - - By CHGuilford (****) Date 09-06-2005 16:20
Our shop doesn't do a lot with ASME pressure vessels. We have done a fair number of tanks under API 620 and 650, and chemical storage tanks. But yes we have used FCAW for longitudinal and circumferential seams with both carbon and stainless steels. Many of the welds have been radiographed with no problems.

Chet Guilford
Parent - By rodofgod (**) Date 09-09-2005 22:18
Hi All!

FCAW is totally capable of producing the highest quality of welds,both mechanically and defect-free wise! However, poor operator skills can lead to some welds having a typical LOF or SLAG entrapment in these welds! Not all these defects are detected by radiography alone, we grind the cap flush and carry out UT testing after rad on all large bore FCAW butt welds! UT ndt is much more likely to find certain defects common to FCAW than radiography alone!
Welder training is most important when using this process for any type of 'class A type' work.

Regards
Up Topic Welding Industry / Technical Discussions / Effectiveness of FCAW

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