Tubes are manufactured from steel strips, slit from Cold Rolled Low Carbon Steel coils. The strip passes through a series of drive forming and fin rolls and takes the required circular shape and is welded continuously by passage of an electric current of high frequency i.e. 4,50,000 cycles/second across the abutting edges. The tubes thus formed and welded pass through the sizing sections where dimensional deviations if any are corrected before the tubes are cut into required length by automatic cutting machines. The tubes are then end deburred. Thereafter protective surface finishing operations such as varnishing is done as per specific requirement.