By bhines
Date 03-21-2006 16:22
Call the manufacturer of what ever wire you are using find what is recommended on volts and amps and on top of that run on the low side and stringer runs only. multipass do not wieve it puts more heat in the piece and has a chance for failer. let it cool between passes.
By -
Date 03-22-2006 00:25
As bhines said, it is imperative that you follow qualified, proven procedures when using FCAW, primarily because the oxygen associated with the internal flux tends to lower the impact strength when impacts are required. Personally, the brand of wire is secondary to the importance of following qualified procedures.
Chuck
In addition to the already posted comments, the big question is how many ft-lb do you need at -20F? If it isn't too much, any wire classified as E71T-XMJ should do the trick as they are classified to the specification requiring -40F impacts. Some examples are Tri-Mark TM-770, and ESAB Dual Shield II 70T-12. Both wires are classified as an E71T-12MJ. We have used the DSII 70T-12 without problems and have tested it at -40F.
I agree with GRoberts, there are several FCAW electrodes that are tested at -20F, but it is the ft/lbs at that temp that is the important info for choosing your wire to conform to your contract specification.
Many mfg's advertise the performance of their welding wire in an "as welded condition" at -20F and some even test at -40F. Also I have found that there are mfgs that don't have that info shown in their catalogs but have that info available upon request.
John Wright
Why not just go to a manufacturer who offers actual test results on mill certs stating the impacts at -20 or -40. Some offer this free of charge and can give you the mill cert to a good heat ahead of time. Then there is no doubt.
Zeke
By -
Date 03-23-2006 13:59
Per ANSI/AWS A5.22, the only mechanical test required by manufacturers of FCAW are chemical analysis, radiographic, and tension tests. The only impact test (5 specimens at -320F) is required for the E316LT0-3 electrode classification. Fillet tests are required only on certain designations, also. For special impact tests at specifically designated temperatures, most manufacturers require a P.O. stating what requirements are requested. Most manufacturers will state impact values (normally +20 and -40C) as "typical" values on their data sheets for individual grades, but for "actual" impact values an impact test at a certain temperature has to be done, and it is not "required" per Code. I'm not saying it can't be done, just that it is not required per Code, and most manufacturers will not perform tests that are not required. Again, "most" not necessarily "all".
By -
Date 03-23-2006 15:17
Sorry everyone, I didn't pay close attention to the post which was referring to CS wire. As all can see, I was referencing SS fcaw wire specifications. Sorry for my error.
Stringer beads, low heat input and a good wire. Also watch your interpass temperature (stay below 350°F).
Around here (Eastern Canada) the wires of choice are either Nittetsu SF-3 (made by Nippon Steel) and an Air Liquide T12 wire. Iimpact requirements needed around here vary but range between 27J@-27° and up to 47J@-40°C... During procedure testing with the SF-3 we have obtained impacts that far exceed the impact requirements mentioned above.... other people I know have had similar results with the T12.
Both FCAW wires that have extremely good charpy properties on paper and in practice. I have personally tried the Nittetsu wire and love to weld with it, the slag just peals right off - although it is expensive.
