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Heating duplex weld joint by TIG arc welding

Karik87

Mechanical
Aug 24, 2021
19
Hi experts,
The welder has just completed a weld on a Duplex stainless steel pipe (A790 UNS S31803). After welding, He noticed a significant misalignment between the tee and the pipe — clearly, the joint has distorted more than expected.

To correct this, he applied TIG arc heat onto the cap layer of the weld in an attempt to realign the components. No filler was added — he simply used the arc to locally reheat and relieve stress in the distorted area.

My question is:
🔧 Is this practice acceptable for duplex stainless steel welds?
⚠️ Are there any risks to mechanical properties or corrosion resistance from using TIG arc for distortion correction like this?
❌ Is this prohibited or discouraged in any applicable welding or metallurgical guidelines?

I understand that duplex materials are sensitive to heat input and thermal cycles, so I’m concerned this may affect the phase balance or introduce unwanted microstructural changes like intermetallics.
I’d really appreciate insights from others who have dealt with similar issues. Have you used this method before? Did you perform any tests (e.g., hardness, corrosion, microstructure) afterward?
Thanks in advance!
 
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I presume that there are cases where it will be exceeded, so there is some margin in it.
In 2205 I could live with and actual upper limit of 250F, maybe even 275F.
It really depends on what the heat input in the weld is.
In a superduplex though I would stick with 200F.
I'll clarify that every duplex application that I work with is pushing the limits on corrosion resistance.
OK good to know
 

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