What Are the Two Main Methods Used to Produce Seamless Steel Pipes?

        The industrial production of seamless steel pipes mainly follows two routes: one is the piercing-rolling method(Bias rolling / Mannesmann type), and the other is the extrusion method (hot/cold extrusion). Each has its own process flow, advantages, and applicable scenarios. Understanding the differences helps in selecting the appropriate pipe material for different applications.

        Ⅰ. Perforation-rolling method (Mannesmann / rolling type)

        This method uses solid round billets as raw materials, first heating them to a plastic state, then piercing them on a piercing mill using a tapered piercing element or piercing rod to form a tube. The seamless steel tube then undergoes rolling, sizing, and other processes, followed by heat treatment and final product inspection. This process is suitable for mass production and a wide range of outer diameters. Representative processes include skew rolling piercing, longitudinal stretching, and Menesmann ferrule rolling.

        Advantages: High production capacity; suitable for medium to large diameter and thick-walled tubes; good adaptability to conventional carbon steel and alloy steel.

        Ⅱ. Extrusion method

        Extrusion typically involves placing a heated tube blank in a closed extrusion cylinder, where it is extruded into a tube by a piercing rod and an extrusion bar. Hot extrusion is suitable for the production of small-diameter or special alloy tubes; for certain high-requirement applications, it is often combined with cold drawing or cold rolling to further improve dimensional accuracy and surface finish.

        Advantages: Concentrated forming force, good internal and external surface quality,and the ability to produce high-precision small-diameter or special alloy tubes.

        Ⅲ. How to choose the right seamless pipe?

        If the project requires large-diameter, thick-walled pipes for mass production (such as water supply or structural pipes), the piercing-rolling method should be given priority.

        If the requirement is for small-diameter, high-precision pipes or special alloys, extrusion combined with cold working is more suitable.

        A common mixed process in the same order is to first use rolling or extrusion to form the pipes, and then use cold drawing/cold rolling to finish them to achieve the final dimensional and mechanical performance standards.

        Metal has built a closed-loop quality system from factory to site by integrating raw material inspection, production process control, non-destructive testing, disinfectant and preservative treatment, and on-site processing. For samples of seamless steel pipe or technical support for inspection items, please contact us for customized solutions and quotations.