Welding Tips and Tricks

There has been discussion at work lately about which tig wire is best for pipe welding. Most say ER70S-2 is crap because suck back is easy as is rolling silicon under the weld pool. Most prefer ER70S-4 and I've had a welding inspector say ER70S-6 is best and seen it used by experts who swear by it. I learned on ER70S-2 and not dropped any x-rays, same with ER70S-4 which I have been using for nearly a year now. So I thought I would compare all three.

Pipe was 3" sched 40 low carbon steel in the 6G position.
Root gap was 3/32" with 30 degree bevel and knife edge.
Wire was all 3/32" (2.4mm)
Argon at 11 L/min
Electrode was 3/32" Lanthanated 2%
Root pass 105amps lay wire forward/back method
Fill pass 110amps
Cap 125amps.

Marcos

Top macro is ER70S-6
No inclusions, or faults visible. Good fusion. A little reinforcement at the root. The weld pool was more fluid which can be seen as slight sag on the bottom of the cap which could be seen as a stress concentrator by a picky inspector. I liked the way the it was more fluid and was very nice and easy to use for the first time.

Middle macro is ER70S-4
No inclusions or faults visible. Good fusion. Plenty of reinforcement at the root. No sharp corners on the cap to pipe fusion. Also very nice to use but not quite as fluid as the -6 wire.

Bottom macro is ER70S-2
No inclusions or faults visible. Good fusion. Root is flat but still passing, no suck back. Most even cap. Using this wire for the first time in quite a while I found it cumbersome due to the more "viscose" weld pool which did not flow as easily as the other wires. Technique I suppose would improve root reinforcement.

My conclusion is that all three wires are usable and have their places. I found the ER70S-2 the most difficult to use and would prefer not to use it. I would most prefer to use the ER70S-4 because I know that I will get good root reinforcement with my preferred method. I would also be pleased to use ER70S-6 wire because it is easy to use and I would be confident that there would be no suck back.

I think all three of the above welds would pass DT and NDT.

Final comment: I spoke with a large filler manufacturer's tech support. They stated that I should not be able to tell the difference between the three fillers. Clearly this guy is not a qualified tig welder himself because I could tell all three were distinctly different.

My skills have a long way to go before this info is relevant, but I appreciate what you've done here and I look forward to being able to tell the difference myself one day. Meanwhile, I have 40# of ER70S2 that'll last me a good while.

Richard,
the good news here is that becoming competant with ER70S-2 filler with lots of practice first means that using the other fillers is a breeze and you really appreciate what they can do. Going the other way round would mean that you would really struggle trying to use ER70S-2 later.
Cheers.

I don't notice any difference in the filler used all three before

Sent from my SM-N9005 using Tapatalk

The main difference in composition is the amount of silicon in the rod, with -s2 having the least, and -s6 the most. The average welder won't usually notice a difference, unless the parent metal is unusually clean or dirty. I don't mean in terms of prepwork, but rather the composition of the metal itself. A 3X recycled steel from China will have more imurities than a 1st-melt virgin steel from the U.S.

I suspect because 95% of the steel we encounter falls somewhere in the middle, the -s4 rod will perform better for those who can notice a difference.

I doubt I'd easily notice the difference myself, as all the pipe I've TIGged for several years has been either SS or Al.

Steve S

thanks for posting up the pictures. Great info.

Coldman - an interesting read, thanks for posting it

I'm fairly new to tig (under 3 years off-and-on) and have only used 70s-2 so far.
I'm more open to trying the others after reading this.

If I read you correctly, I'll notice that I pay less attention to focusing on the wetting out of the puddle.
I think I'd like that

Excellent information, much appreciated!

Wow, I'm an arse...

Chimed in with my three cents on rod composition, and didn't say,

Thanks, Coldman, for taking the time to set up these tests and share your results!



Steve S

I have welded hundreds , if not thousands of pipe joints ,such as open root,closed root,backing ring,E.B.rings, socket,and varies other joint types,using 70s2,70s4,and 70s6.There are slight differences,but not enough to effect the end results, such as x-ray,m.t.,p.t., or u.t.....As far as the excessive silicone in the filler wire, the only problem would be silicone inclusion in the base metal if you trapped it in the puddle while welding.Also, silicone is a de-oxidizer,so the puddle will be more fluid, and weld cleaner. The trade off is more silicone floating in the puddle, hence, more of a chance of silicone entrapment,resulting in a possible x-ray reject....... hope this helps in some way. Ron.

Ron, you don't happen to live in Ohio do you?

Wow great info!!!
U wouldn't happen to live in Melbourne would you?
If so feel like give a bloke a little extra training? My teachers sucked balls!!

Drifta-X wrote:Wow great info!!!
U wouldn't happen to live in Melbourne would you?
If so feel like give a bloke a little extra training? My teachers sucked balls!!

Sorry Drifta, I'm in God's own country. If you're ever up this way...

in answer to GreinTime's question as to where I live,I live in Tacoma, Wa.

I gotcha. There was a guy we jokingly referred to as the Steel Dr. down here because he was the only non-doctor at the go kart country club, but he owned a pipe and structural welding company. He was a pretty cool dood.

This subject was already discussed here, year or two ago. I believe Jody did even a video about this one, where he used mig wire as tig wire, which was S6. Couldn't find that video with a quick search...

I think there definetly is not major diffence. Both wires S2 and S6 will work and produce quality welds, as already said. However I have noticed that with S6 it's easier to keep cleaner puddle and produce just slightly "neater" welds.

Intresting point which was written here, was creating suck back easier with S2!! I strongly doubt that, but then again with different techniques it can be possible. I might test that when got some time.