Welcome to UKWelder Welding Caps Welding Helmets Pioner Overalls Welding Gloves
UKWelder Shop
Welding Hoods Welding Leathers Welding Helmet Spares Welding Boots

Welcome Guest ( Log In | Join the Forum )

Reply to this topicStart new topic
> Duplex questions
post Jun 19 2018, 07:02 AM
Joined: 16-Jun 18


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.

Please help.

I didn't find the right solution from the Internet.

Technic Al
post Jun 19 2018, 08:41 PM
Joined: 14-Oct 03

Not sure what you mean "need to know how to weld it"

Basically it acts like the 316L youve been welding....theres the metallurgical aspects you mention. The only other thing I can think of is that large welds give the best results from both a corrosion and a mechanicals point of view.

Im assuming you know about heat inout, interpass temp, overmatching etc etc
post Jan 21 2019, 01:39 AM
Joined: 21-Jan 19

If you have experience welding stainless you shouldn't have a problem with duplex. You'll find it doesn't melt or flow in quite the same way but it's not a whole new experience.
You might find it'll take another 10 amps or so for any given task.
If you're welding any pipe roots it needs more care with the penetration as it doesn't sink the same, freezes faster. It also doesn't pull and warp as easily as 316.
post Jan 22 2019, 04:35 PM
Joined: 30-Jun 11

If you are doing any grinding on it, wear a face mask. I was told that duplex particles are like barbs. Inhaled can stick to your lungs .
post Jan 24 2019, 11:16 AM
Joined: 9-Dec 07

Try and get a copy of " Practical Guidelines for the Fabrication of Duplex Stainless Steels" by the International Molybdenum Association from the UK.
If you can't find on the internet PM me and I will send you a copy.
It doesn't tell you how to actually weld Duplex (as explained above it is not much different than basic S/S) - what it gives is the does and don'ts of welding DSS or SDSS,
Go to the top of the page
Start new topicGo to the top of the page
Click on the Lion to return to the homepage Click on the Lion to return to the homepage