Rotating welding system and methods

A field system for welding two pipes, comprising:

• a first pipe engagement structure configured to engage the interior surface of a first pipe to enable the first pipe engagement structure to be fixed relative to the first pipe;
• a second pipe engagement structure configured to engage the interior surface of a second pipe to enable the second pipe engagement structure to be fixed relative to the second pipe;
• a weld torch configured to be positioned within the pipes to create an internal weld at an interface region between the pipes;
• a motor operatively with the weld torch to rotate the weld torch along the interface region between the pipes;
• and
• one or more processors that control the motor and the weld torch, the one or more processors operating the motor and the weld torch to generate a complete circumferential weld along the interface region by rotating the weld torch along the interface region in a single rotational direction until the complete circumferential weld is completed,
• wherein the one or more processors are configured to cooperate with the motor to enable the motor to change a lead angle of the weld torch throughout a welding operation such that the weld torch rotates at least rotates 360 degrees, in both an upwards direction against the force of gravity and a downwards direction with the force of gravity, in the single rotational direction to complete the circumferential weld, and
• wherein the weld torch is configured to travel in a generally vertical plane in the single rotational direction for at least 360 degrees, while the lead angle is changed by the one or more processors and the motor to accommodate for changes in gravitational forces upon the weld during the rotation in the vertical plane, until the complete circumferential weld is completed.

A method for welding two pipes comprising:

• engaging the interior surface of a first pipe of the two pipes with a first pipe engagement structure to enable the first pipe engagement structure to be fixed relative to the first pipe;
• positioning one or more weld torches within the pipes to create an internal weld at an interface region between the pipes, the one or more weld torches being operatively connected with the first pipe engagement structure;
• rotating, using one or more motors operatively associated with the one or more weld torches, the one or more weld torches along the interface region between the pipes;
• and
• operating, using one or more processors that control the one or more motors and the one or more weld torches, the one or more motors and the one or more weld torches
• to generate a complete circumferential weld along the interface region by rotating the one or more weld torches along the interface region in a single rotational direction until the complete circumferential weld is completed, and
• to change a lead angle of the one or more weld torches throughout a welding operation in which the one or more weld torches rotate along the interface region in the single rotational direction until the complete circumferential weld is completed,
• wherein the one or more weld torches are configured to travel in a generally vertical plane in the single rotational direction, while the lead angle is changed by the one or more processors and the motor to accommodate for changes in gravitational forces upon the weld during the rotation in the vertical plane, until the complete circumferential weld is completed.