I have a disagreement in my shop about the strength of 7018 stick vs 70S wire. To me, they are both rated at 70,000lbs., and if both applied properly, are equal in strength. I have been a ship welder in the past and have always used 70S where it really counts. The opposition(the poor misinformed clods) have just enough welding knowlege to make them dangerouse, and insist using stick will make a stronger weld. Are there any opinions out there from someone who is a more better welder than me? I'm pretty sure of myself on this, but I'd like to know if I'm wrong.
Thanx,
Buffalo
The opinion is fact:
ER70S has to meet a minimum 70 kips tensile strength in the as-welded condition. (Ref:AWS A5.18 & A5.28)
E7018 has to meet a minimum 70 kips tensile strength in the as-welded condition. (Ref: AWS A5.1 & A5.5)
it sounds like your cohorts don't know how to set up a MIG machine...hehehehe. ofcourse a 70S weld isn't gonna hold up if you don't have the heat and wire feed speed set right. you also have to watch out for cold lap and porosity, which isn't quite as much of a problem w/ stick welding. you also have to figure out how to read the puddle so the arc isn't "riding" on top of the molten puddle instead of in front of it where it can melt the base metal at the root.
my boss insists on using MIG on any mild steel, except where there is lots of oil, rust, or dirt, in which case a stick welder would work better.
Buffalo, the tensile strength may be the same but the "strength" issue will become important in the application process. If you are using short circuit mig on 1" plate, with ER70S-6 wire, your weld metal will have 70K tensile but you will have a problem obtaining a weld that will pass a bend test. If you are using this in a spray transfer mode, then you will probably be okay. This is precisely the area where this question has come up before. The important thing here is that as you said, it must be applied properly.
Mike Sherman
Shermans Welding
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