Need info for B337Gr2 welding

Hai people,
Can any one tell me some item :
1. Pipe welding of B337 Gr.2 to B337 Gr.2, is that mandatory to use UHP argon gas for primary, secondary and back shield ? 2. During welding of material above, some of dirt producing activities
(grinding, cutting, etc) has to stop. Why?
3. How long is the free distance (to do grinding and cutting) required during B337 Gr.2 welding ?
(FYI, i work at open area 20m x 20m for fabrication surrounding by 40ft
container)
Any suggestion will be appreciated. Thanks in advance.

Bled

[Non-text portions of this message have been removed] Received on Wed Aug 08 08:41:00 2001