The production of spiral welded pipes involves various forming methods.

Spiral welded pipes are formed by pre-bending and continuously bending steel plates or strips on a forming machine, resulting in a tubular shape with spiral seams. Characterized by long weld seams and high production speeds, spiral welded pipes are suitable for the production of large-diameter welded pipes. There are multiple types of spiral welded pipes based on different classification standards, mainly including: (1) Classification by adjustment method of the forming angle: front-swing type and rear-swing type. (2) Classification by feeding method of the forming machine: up-coiling type (less commonly used, only in special occasions) and down-coiling type (more commonly used). (3) Classification by forming method of the forming machine: down-coiling roller bed forming machine, sliding friction full-sleeve forming machine, combined sleeve and roller forming machine, rolling friction full-roller sleeve forming machine, and PRD forming machine (invented by the American company PRD, capable of continuously adjusting the pipe diameter).