Following 3 welding methods are used:

 Plasma Arc Welding, PAW
 Tungsten Inert Gas Welding, TIG or GTAW
 Submerged Arc Welding, SAW

All welding is performed in automatic operations.

Welding procedures
Depending on type of grade, wall thickness and customer requirements a certain welding procedure (WPS) is used. We have a large library of WPS's and 4 main procedures can be identified:

I-groove Double PAW	I-groove Double PAW + TIG inside
Y-groove PAW+SAW+TIG inside	X-groove PAW+SAW outside + SAW inside

Filler metal is used in most passes, except for thin wall and intermediate PAW. Inside means welding from the inside of the pipe. TIG welding is used primarily to smooth out the inside bead.