The application provides a
thick plate ring joint
narrow gap arc welding process, which comprises two groups of to-be-welded cylinders in
butt joint, forms a
narrow gap weld, and the
narrow gap weld is in a ring state; a coordinate
system is established with the center of the to-be-welded cylinder as an origin, the normal line of the cylinder as a Z-axis direction, an X-axis as a horizontal direction and a Y-axis as a vertical direction; a
metal backing plate is arranged in the narrow gap weld, the
metal backing plate is at an angle of 45 degrees with the normal line of the to-be-welded cylinder, and a triangular area is formed between the
metal backing plate and the to-be-welded cylinder; a
welding gun moves in the X-axis and Y-axis directions, completely fills the triangular area, completes initial weld filling, and the
welding pool plane is parallel to the X-axis; the
welding gun moves along the X-axis direction, meanwhile, a roller frame drives the to-be-welded cylinder to roll, the welding
pool plane is always parallel to the X-axis, and the metal backing plate intersects with the welding
pool plane at the welding end point and is perpendicular to the welding pool plane; the welding gun moves along the X-axis direction, meanwhile, the welding gun is lifted along the Y-axis direction.