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[MW:23766] Distortion in SS pipe welding

We are doing pipe to pipe welding of A358 material ( Dia DN250 and thickness is 9.53)

In that we are facing distortion problem. To control the same we have tried various process and technique as below.

1. First Welding- We did welding with GTAW process and observed the diametrical distortion approx. 4 to 6 mm.

2. Second Mock up- We change the welding process from GTAW to GTAW+SMAW with restricted root gap 2mm follwed by cleat in four location of seam. And also we did welding opposite segment one by one. In which we observed distortion upto 2 mm except one local portion 3mm.

3.  Third mock up- We followed the same process except welding sequence. This time we completed welding using back step method and found same result as in second mock up.

For both second and third mock-up we strictly maintain inter pass temperature. 


Now can anyone guide weather 3 mm distortion is acceptable?

if yes then please reply with on what basis it can be accepted.

and if not then what method can we try further to control distortion to bring it in acceptable limit.



Thanks/Regards
Saurabh Mishra

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