What are the technological methods of automatic welding machine for long distance pipeline? Automatic welding of long-distance pipeline is mainly divided into: automatic welding of main line, automatic welding of tie-in and automatic welding of station.

Main line automatic welding: For pipeline dia. 813mm and above main line automatic welding, internal welding machine with GMAW is mainly used for root pass welding, double torch GMAW is used for filling and capping. Pipeline dia. below 813mm, GTAW is mainly used for root pass, single torch automatic welding with GMAW is mainly used for filling and capping.

Tie-in automatic welding: GTAW is mainly used for root pass welding. Single torch automatic welding with GMAW is used for filling and capping.

Automatic welding of station: due to the space of pipeline layout in the station and other reasons, automatic welding is rarely used at present. Some contractor also uses TIG to weld as root pass, single torch automatic welding with GMAW to weld filling and capping. Some contractors are exploring the welding method of both root pass and filling & capping being welded by single torch automatic welding machine. This method is not widely used because the qualification rate is unstable due to the influence of external environment. With the continuous progress of equipment and the advancement of welding technology, some new pipe automatic welding methods will continue to emerge.