Pipe Welding with Lincoln STT 1

[Guest102023]

I am considering Lincoln STT for up to 3/4" thick st. st. pipe, up to 30" diameter. Work will be done in a shop, so pipe rotation will be done. Experiences and advice on joint design and techniques (especially position) sought. Also purging techniques/materials.
I understand Miller has a similar technology but I have not yet investigated.
Thanks

 

[holdpt]

Miller's is called RMD and I don't think you'll see any significant difference in performance so cost will probably guide your decision making. Both manufacturers have joint configurations that they suggest as well as gas mixtures (when applicable) and other procedure variables.
I am curious about the performance of Tip-Tig. They claim even more production speeds.

 

[SJones]

TOPTIG won't do those thicknesses

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Guest102023]

I'm not interested in semi- or auto- TIG or anything robotic. I am more interested in the details of the welding itself - joint prep, position, gas (shield & purge), etc. I am not buying equipment or doing the welding.

I've since learned that STT is only good for the root pass, but a Lincoln Power Wave with STT option can complete the job in normal GMAW. Sounds like a good way to go.

 

[stanweld]

Your best use of the STT and RMD for the welds stated is for the root and hot pass only with fill passes made with the SAW process (diameter permitting) or the spray transfer mode of the GMAW/FCAW processes (STT/RMD only for root pass. Welding with the STT/RFD systems can be done in all positions.

 

[holdpt]

@ SJones
I said Tip-Tig, a machine that an acquaintance of a friend developed. It uses the GTAW process but feeds the wire by a controller on the torch. There should be no limitation on thickness. I haven't even heard of Top-Tig until your post so thanks for the info.

 

[SJones]

Likewise, I'd never heard of TIP-TIG

@Brimstoner


Welding Journal, June 2007, page 66

Welding Journal, June 2008, pp 66-68

Journal Of Industrial Technology, Vol 19, (4), 2003, article by B D DeRuntz

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Guest102023]

I bought several wire-feed TIG machines back in about 1996. They worked very nicely, so I already know about that.

 

[SJones]

The articles are about STT and RMD. The 2007 article is specifically about experience with large diameter stainless pipe.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Guest102023]

SJones,
I don't have those issues and can't locate the articles on the www. Any chance you or anyone else can post them here?

 

[SJones]

Sorry - copyright

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Guest102023]

Can you supply the article titles? I am hoping the manufacturers can supply them.
Better yet, just the details of wire Ø, gas, purge parameters and joint design for a root pass with ER309L.
Thanks muchly.

 

[holdpt]

See page 81.

http://www.lincolnelectric.com/assets/en_us/products/literature/c4200.pdf

 

[SJones]

Very general papers really. No WPS details that you could get your teeth into.



Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Guest102023]

Thanks, holdpt!

 

[vanci]

I have witnessed 100% penetraion of a root pass with 1/8" land, no gap on 304 in 2G position using STT. It appeared thicker than 1/8" would have been possible. Wall thickness was over 1". Most of the STT parameters I have seen were in synergic mode using a tri mix shielding gas.