Jon said it right. FCAW is common in pressure vessels. Tons of it is welded on them every day. And traditionally impacts have been an issue for wires because you can only fit so much stuff inside those little wires. By the time they get done with shielding gas generators, wetting agents, fast freeze agents, deoxidizers, etc., there ain't much room left. But the standard 20/20 (20ft/lbs/-20degF) test has become routine for CS wires to achieve and some wires do far better.
Even low ally wires, say, of the CrMo variety are much improved in impacts, even though they are intended predominantly for high temp applications where toughness is generally not considered an issue (there are concerns for cyclic/start up/ambient/cold weather shipping toughness).
By George-kh
Date 04-01-2007 20:42
Edited 04-01-2007 20:52
Rutile wires with fast-freezing, stiff slags (E71T-1 types) are available for all-positional welding, where-as downhand versions (E70T-1types) use more fluid slag for high travel speeds. In both cases, slags are easily detached. Ni alloying with Ti, B-micro alloying provides good low-temperature toughness down to -50 C degree and CTOD properties (E81T1-Ni1 types); but only in the as-welded condition. Higher required strength levels become increasingly difficult to match with sufficient weld metal toughness and cold-cracking resistance. The rutile formulation is also less suitable for creep-resistant types, because stress relieving reduces weld metal toughness. In both cases, basic cored wires offer a better basis.
However, risk of lack of fusion on thick base metals is high with basic type cored wires, because of short-circuiting metal transferring, which occur with basic type cored wires. I know ESAB has developed some basic type cored wires with spray arc metal transfer mode, which has solved this problem but I can not remember their trade names. Contact ESAB for more detail.
thanks,Jon,Js and George.
I mean whether FCAW process can be used in main weld seam of pressure vessels, not only be used in nonpressure parts welded to pressure parts. If it can be used, what the specification for the FCAW wire is, such as content of hydrogen diffusion, strength,etc. At present, what types of materials can be welded in the manufacturing of pressure vessels except carbon steel, stainless steel. Can it be low temperature steel, heat-resistance steel,etc? If it is SA516 Gr.70 or 60, which wire should i choose?
Many thanks.