Steel pipe export China

5.The classification of roller forming methods for longitudinal welded pipes includes three main categories: phased forming, natural forming, and vertical roller forming.

Phased forming involves a series of die rolls arranged longitudinally. It can be further categorized based on transverse forming characteristics and longitudinal forming characteristics of the pipe blank. Transversely, it includes edge bending, center bending, circumferential bending, and double-radius die bending. Longitudinally, it includes uphill forming, downhill forming, bottom line horizontal forming, and edge line horizontal forming. Advancements in phased forming methods, such as W-reverse bending and F.F forming, contribute to improved longitudinal welded pipes forming quality.

Natural forming, also known as edge roller forming, controls edge extension by configuring roller groups along the outer edge of the pipe blank. It absorbs edge extension as compressive deformation, making it suitable for large-diameter thin-walled pipes.