Welding Tips and Tricks

Hi everyone! A quick introduction. Started with TIG welding 3 years ago. At first it was only carbon steel pipes with some stainless last year. For the last 5 months I've been welding only 304 and 316 SS with some aluminum here and there. It's a relatively big workshop, but there are only two weldors. Everything else is manual machining and CNC work. So I come across a lot of things: small delicate parts, big contraptions for food processing, big thin wall pipes, sheet metal welding... It has been a really steep learning curve for me, with lot's of mistakes to learn from.

Next year we'll have lot's of big parts made out of Duplex. 5 mm to 13 mm thick, machined and cut, everything should be welded with corner welds. It's a standard Duplex, 2205 variety. But, I have never worked with Duplex. I have found a lot of general information about Duplex from a metallurgical standpoint, but I need to know how to weld it.

What considerations for Duplex welding I should know about, compared to 316 SS, for example? I'm sure there are a lot of weldors on the forum who have welded Duplex, so any information would be really appreciated.

Cheers!

It sounds as though the duplex parts are not pipe, so I am assuming your not welding for full penetration. I use to do duplex pipe and we'd use Ar/3% Nitrogen mix for the purge gas.

This site has a 68 page PDF file that includes a section on fabrication, should answer your questions.

Scroll down about half way and look for the publication "Practical Guidelines for the Fabrication of Duplex Stainless Steels "
and download the pdf

Right, no pipes for now. Just thick plates, big rods and machined parts. Thank you for the link. Hopefully I would find what I need.

Aside from the purging gas and filler rod, what did you do differently when welding Duplex pipes, compared to 316 SS?

Watch the heat input, other details are the same as stainless and equally important, weld prep of materials and good welding procedures.
Specifically if you follow the guidelines in the link you'll be fine.