We presently have only one qualified FCAW procedure and we do not use it often. Our results seem to be unpredictable when we do use it and I think it may have something to do with the quality of the wire that we have purchased in the past.
I now have an opportunity to develop and qualify a new WPS for an AWS D1.4 requirement. Requirements in D1.4 lead me to select an E7XT-X or an E7XTX-X electrode. After going through all the appendix guidance of D1.4 and electrode specs AWS A5.20 and A5.29, it seems that I will want to use an E71T-K2M because it of its low sulfur merits, its good Charpy value and high elongation. According to the "M" designator, I should use 75/25 Ar/CO2 mix which we have on hand. We can use a Millermatic 350P machine.
My first problem is I can't seem to find an E71T-K2M wire. ESAB, Lincoln or Hobart do not have this particular wire. So I need to discuss my application with manufacturers to determine an alternate.
Can you all make a recommedation on your preferred hands down favorite FCAW brand that you have had consistently good results with and can count on high quality wire. Thanks.
I purchase KOBELCO wire here in the Houston area, Kobelco rep always a great help, and the product always as represented. Not the cheapest wire around, but when it gets the job done, well you know what I'm saying. I just work the extra cost of some of the premium wire into the quote, keeps the QC guys happy as well.www.kobelcowelding.com has a good web site...so you can look around.
For E71T-1 wires I prefer Hobart Excel Arc 71 or Trimark 777. Both give good arc characteristics when used with C-25 gas.
Tom,
How did the lifting lug situation work out for you. Remember there was high sulphur and phosphorus content. The Lincoln rep suggested that you use E8018-C3 SMAW. If you are looking for the FCAW wire E71T-K2M, not sure if you will find it. What I did find is Lincoln's Outershield 81K2-H, which is E81T1-K2MH8. Seems to fit the profile of what you are seeking but, with a higher T.S. The other thing I noticed is it is used in place of E8018-C3 for improved efficiency. Hope this helps.
Mot-
The lifting lug!!!! We cut new teeth on that one. But it worked out fine. Here is what we did:
Chased cracks into the base plate as deep as 3/16" deep in some places;
dye pen all to prove we were clean;
preheated to 450* F and let it soak for hours;
built up the excavations to the baseline surface and sent to the machine shop for finish grinding;
dye pen again;
preheated to 450* F and let it soak for hours;
layed 1/8 beds of 8018-C3 (low amperage) under the footprint of the fillet welds only but not under the body of the lug;
hot magged the beds;
held a 3/32 root gap and filled in the bevel welds.
hot magged the roots;
filled out the filletwelds;
held preheat temp for 2 hours and slow cooled;
waited 48-hours and wet magged;
dimensional checks on lug;
sold off to QA on 2/21.
Now that you reminded me, I should go back to that post and offer the above process for any future readers.
Thanks for the reminder.
Your mention of using the higher tensile wire, 81K2-H for my new application scares me a little EXACTLY because of some of our experience with the lug problem. On that job I originally speced a 9018 rod, higher than the tensile strength of the base mat'l and originally didn't leave a root gap. I am not altogether certain that the high tensile rod didn't contribute to some of the cracks and tearing we found deep into the base plate. I developed new ways to be gun shy about things. But thanks for the mention of it.
There are number of FCAW wires with great CVNs. IMHO think you may want to try a T-12MJ wire and not a T-K2M if you can. Lincoln's Ultracore 712A80 had great CVNs has 3.1 traceability and decent performance - I've had good success with this wire. Select Arc has a T-12MJ wire (don't know what its called), in Canada its branded by Air Liquide and they call their T12 wire. The cadillac of wires used around here is a Nittetsu Sf-3A or a 3AM depending on the mechanicals that you need. Again it has 3.1 traceability and the wire is sealed by welding, not just drawn together. A lot of fabricators around here love it because it is welder friendly. Owners don't like it because it is more expensive than the Lincoln.
Sean
Forum
