No significant difference. The Mig is low hydrogen as is the E7018. I would trust the Mig a bit more because the E7018 might not have been stored in an oven.
Iggy's question is interesting - certainly to me - and I would like to know practical experienced knowledge / insight on this.
7018 welds are very strong and tough - often get general bending of the metal around the weld in overstress - protecting the weld. Even when ground-at a lot, reasonable penetration can leave hidden bits of weld remaining, so it can be very hard to break off "temporary attachments" someone has seen fit to do with a 7018 (where 6013 temporary attachment would serve well but is easily removed).
Please - I am also interested in Iggy's question - relatively, how does good ER70 rate alongside 7018?
My criterion would be if it HAS to hold, or is subject to a lot of stress, I'd stick it. Yes, you can crank up the amps on a wirefeed, but I just feel more confident with a hot 7018, or even 7014 vs. E70.
It seems, according to the textbook, that the two are pretty much equivalent - they both give a joint with 70,000psi tensile strength. One difference to E7018 is that it can be used with AC, while the ER70s3 is recommended for DC+. Your Mileage will vary, I'm not a welder, nor did I stay at a Hotel 6. But I did just finish a class on the subject, "and I've read a book".
-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."
My criterion would be if it HAS to hold, or is subject to a lot of stress, I'd stick it. Yes, you can crank up the amps on a wirefeed, but I just feel more confident with a hot 7018, or even 7014 vs. E70.
Should be no difference. I myself use ER70S6, has a little more de-oxidizers in it, I do a lot of repair and the base metal is not always perfectly clean.
If you follow the AWS, pulsed MIG is now becoming the preferred choice for structural welds. Tends not to crack as fast in earthquakes.
I dropped my AWS membership but still get a ton of free trade magazines.
Gunner Asch on Tue, 08 Apr 2014 09:00:32 -0700 typed in rec.crafts.metalworking the following:
Reminds me of my Welding instructor's story about the Alaska pipeline. Seems that the contract called for radiographic inspection of all joints. Which the subcontractor did, for the first 200. Then they got cute and tried to just copy the radiographs for all the subsequent ones. Got caught when an employee thought something suspicious. They had to go and re inspect all the welds. Including the ones which were buried under the rivers. The company wanted to send an ultrasonic unit down the pipe for those, but the court said "radiographic is what it in the contract, and radiographic it will be." So those section were uncovered, cut loose, inspected and signed off, then welded back together, the new welds inspected and signed off, and finally reburied.
Anyway, I've read a book, so I know that what I don't know would fill a book, and that it is more than just "zoooottttt!" and your done. Of course, I knew that back in the day, too. B-) [When 24 of your 28 welds fail ... you know there is definitely room for improvement.]
tschus pyotr
-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."
Shortcuts were -very- expensive for that sub, huh? Aren't most pipelines robotically welded nowadays? Bots with cameras find the junction, weld it up, grind it flat, inspect it, x-ray it, and run down the inside of the pipe to get the next one. Very cool.
You picked up the hint, did you?
Har! That's the thing I love about MIG. It can look so darned good and a fly landing on it can knock the whole blasted thing down. :/ I hope nobody brings up Gunner's runaway trailer tire in this thread.
The difference would have little to do with the weld filler material, and more to do with the weld procedure. If preheat and overall weld heat are the same, the welds should nearly identical.
ER70S-3 isn't used for general steel welding. It is used for only new clean steel. ER70S-6. ER70S-6 has more deoxidizers and is better for general welding, and is closer to 7018 in it's cleaning ability.
21:39:54 -0700 typed in rec.crafts.metalworking the following:
Possibly. Although I'm under the impression that there are trade-off, that some parts of it can be automated, while others still require an idiot to go and hang upside down and weld with a mirror.
I told the boss I'd give it a try. It wasn't critical, just tack welding some sheet metal boxes together.
No, that would not be nice.
pyotr
-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."
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