Welded Steel Tube from Coil (ERW)

Most everyday steel tube is electric-resistance welded (ERW). Steel strip slit from a coil is bent cold through a row of shaped rolls until its edges meet as a round tube; a current passed across the edges heats them, and rolls squeeze them together into a weld with no filler metal. The bead squeezed out is trimmed off, sizing rolls bring the tube to its final diameter, and a flying saw cuts it to length. Low-frequency current was used from the 1920s until 1970, when high-frequency welding replaced it because it gives a better seam.

متقدم

Continuous (industrial)

التعليمات

Slit the coil

The steel coil is slit into strip as wide as the tube's circumference.

المواد لهذه الخطوة:

لفّة فولاذ1000 كغ

Roll-form

The strip passes a series of shaped rolls that curl it, step by step, into an open round tube.

الأدوات المطلوبة:

خط تشكيل الأنابيب بالبكرات

Weld the seam

High-frequency current, induced by a coil or fed by contacts, heats the two edges and squeeze rolls press them together into a solid seam.

الأدوات المطلوبة:

آلة لحام الأنابيب بالتردد العالي

Trim, size and cut

A cutting tool right after the welder planes off the outside bead; the tube cools, sizing rolls set the diameter, and a flying cut-off cuts it to length while it moves.

الأدوات المطلوبة:

خط تشكيل الأنابيب بالبكرات