High-frequency welded round tubes are round tubes produced by welding metallic materials (primarily steel plates) together using the resistance heat effect of high-frequency current, which are then shaped into square tubes. Additionally, high-frequency welded round tubes can be transformed into square tubes through a process called "squaring," where the tube is pushed and calibrated into a square shape by motive force.
High-frequency welded square tubes are commonly referred to as square-rectangular tubes, square tubes, rectangular tubes, etc., named after their square cross-section.
