Method and system for welding conduits

A method for welding two or more conduit members, the method comprising:

• aligning two or more end portions of the two or more conduit members in an abutting relationship to define a gap, the end portions being chamfered in opposite directions to complement each other, the conduit members having an outer circumferential surface side and an inner circumferential surface side, and the gap extending from the outer circumferential surface side through the inner circumferential surface side into an interior area of the conduit members;
• having the inner circumferential surface side exposed to the interior area of the conduit members;
• performing a root weld along the gap from the outer circumferential surface side to configure a root layer while the inner circumferential surface side is exposed to the interior area of the conduit members, the chamfered end portions maintaining any spatter of the root weld material within the gap or on the outer circumferential surface side of the conduit members;
• after the root weld is complete, inserting a support member into the interior area of the conduit members for applying an outward thrust along the inner circumferential surface side and root weld, the support member providing a reactive force to oppose inward plastic deformation of the root weld;
• actuating the support member with an actuating arrangement, the support member thereby expanding along the inner circumferential surface side of the conduit members to apply the outward thrust;
• and
• during application of the outward thrust, performing a filler weld along the gap from the outer circumferential surface side thereof to fill the gap so as to facilitate shrinkage of the filler and root weld materials longitudinally and radially outwardly,
• wherein the actuating arrangement is one of a hydraulic arrangement, a pneumatic arrangement, a mechanical arrangement, or a thermal arrangement.