Wednesday, October 10, 2012

[MW:15545] Purging/backing gas (argon) during welding.

Dear Expert,


Could any one inform me the


Q-1. Why Purging/backing gas (argon) is required during welding of SS(TP 304L, 316L, 321…)?


Generally we do purging for SS welding

1.        to prevent oxidation and

2.       backing for good root profile.

Could you tell me what type of oxidation (chemical reaction) occurs if we don't use purge gas?


Q-2.  Why we don't Purging for A335 P11(1.25 Cr + 0.5 Mo)?


Generally we do purging for those low alloy steel which Cr content is above 2,such as A335 P22(2.25 Cr + 1 Mo).


Could you tell me why purging is not recommended for P11 alloys (chemical reaction/composition will be more appreciable)?



--
Best Regards

Khandaker Imamul Hasan

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