Cooling of SS 304L welding with GTAW 1

[jha1982]

Hello Expert,
I am in a given situation that i am having a weld of SS 304L with SS 304L double V grove weld with root gap 3 mm and plate is made circular of dia 6000MM , thickness is 32 mm. The process is going to be used is GTAW for root and stabilizing pass and SMAW with fill-up and final pass.
I am am seeking help in-terms of following
1.> what should be the arrangement for purging or backing gas?
2.> what should be the arrangement for cooling arrangement?

My important concern is distortion control, tolerance given is Longitudinal is 3 mm and circumferential is 9 mm.
please also provide the sequence of welding if anyone having or knowing.

Regards

 

[metengr]

1.> what should be the arrangement for purging or backing gas?

Use welding grade Argon gas for backing and shielding for the double-vee weld root. Once this is completed, the remainder of the welding is with backing even with GTAW and no backing gas is needed, only shielding.

2.> what should be the arrangement for cooling arrangement?

Keep the maximum interpass temperature at 350 deg F .

Alternate between weld passes for the outer bevel and inner bevel regions to balance residual stresses.

 

[jha1982]

thanks but can we achieve the required tolerance ?

 

[metengr]

There are no guarantees. Follow the advice above, especially the welding sequence.

 

[EdStainless]

How many passes are you planing?
You might be better off making more passes, and making each faster.
You will have to try it.
Alternating sides is a good idea, you may even want to skip around, such as doing opposing quarters of the pass.

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