From Richard Smith@21:1/5 to All on Sun Jan 17 18:30:30 2021
Hi
Seeking most productive high performance vertical-up T-fillet (PF/3F)
GMAW/MIG weld of thicker plate which is possible.
I found for solid-wire GMAW / MIG seems to be 180A stringer-bead.
In welding tests "at the bench" with
* >12mm (1/2") plate
* 1.2mm (47thou") wire
* Ar-20%CO2 shielding gas
Lincoln Foundation's "The Procedure Handbook of Arc Welding" has 175A
for 5/16" fillet 3/8" plate (pg6.6-11 in my recent ver.).
So I'm close / agreeing(?). Go up to 1/2" plate or thicker and there's
your 180A.
Stringer - oscillate side-to-side rapidly to flatten the bead for
profile control, but travel at the natural "full speed" (must not
increase the bead cross-sectional area. The finished multi-run
stringer wasn't "weld porn". But looked to be a very serviceable
weld. Was easy to do. That would seem like reasonable productivity.
I'm thinking - if can hold 180A v-up, is nett easier and as fast with
high arc-on time to kneel on cushion on floor and get into confined
corners to v-up many effectively identical welds, than to turn a
many-tonnes fab. on side, get on platforms, reach into awkward corners
and "spray" PB / 2F at say 250A with welds presenting different
geometries and challenges (the parts of the structure "fly-off" at odd
angles).
Also 180A "dip" (very clean for "dip" and "crisp") is very little heat
and light radiation given close-up confined into awkward corners -
where a searing spray arc makes life quite an endurance when having to
crick oneself into even more awkward constricted corners as presented
when fab. is "on-edge".
Just saying - a welder having a tough time is going to have to accept
a "good enough" which is less advantageous than the "good enough" when
the challenges don't include existential ones (!) ...