The Continuos Root Welding Machine Model CRWM is built to simplify the following internal and external seam welds at longitudinal welded pipes. The CRWM generally is part of a LSAW Pipe Mill where the pipe is formed by different processes e.g. Roll Bending Process U- Forming and O- Forming Process Progressive Forming Process Progressive Folding Process The CRWM can also be part of modernizing an existing Pipe Mill for better quality increasing the output The process is a continuous tack weld under gas shielded arc to achieve the best quality of welds. The CRWM closes the edges of the open seam pipe gas during transportation through a fixed located sizing roller cage. The adjustments of the roller cage are hydro- mechanical and CNC-controlled in relation to the pipe sizes, e.g. diameter, wall thickness, material grade and length.