On-site pipeline narrow gap welding groove structure and assembly method thereof

The invention relates to an on-site pipeline narrow gap welding groove structure which comprises a first pipeline with a first blunt edge and a second pipeline with a second blunt edge, wherein the first blunt edge and the second blunt edge are fixed to form a groove between the first pipeline and the second pipeline; the first blunt edge is a convex-opening-shaped blunt edge; the second blunt edge is a concave-opening-shaped blunt edge; the convex-opening-shaped blunt edge and the concave-opening-shaped blunt edge are in interference fit. The invention further provides an assembly method for the on-site pipeline narrow gap welding groove structure. The assembly method comprises the following steps: heating the concave-opening-shaped blunt edge to 150-450 DEG C or cooling the convex-opening-shaped blunt edge to minus 50-minus 150 DEG C, inserting the convex-opening-shaped blunt edge into the concave-opening-shaped blunt edge to form a whole, wholly cooling or heating to room temperature or welding preheating temperature. According to the invention, the structure improvement that the convex-opening-shaped blunt edge is matched with the concave-opening-shaped blunt edge is adopted to replace conventional spot welding fixing, narrow gap welding can be realized without a complex tool clamping apparatus, the structure and mounting are simple and the welding quality can be improved effectively.