METHOD OF MANUFACTURE OF PIPE LINES FROM ENAMELLED PIPES Russian patent published in 1999 - IPC

FIELD: manufacture of pipe lines from enameled pipes; erection and repair of pipe lines under field conditions. SUBSTANCE: method includes application of enamel paste on outer surface of backing ring, assembly of pipes for welding and mounting backing ring inside pipes at joint area followed by welding the pipes by circumferential seam accompanied by burning of enamel in the course of welding. EFFECT: reliable protection of weld seams against corrosion; increased service life of pipe lines due to even distribution of enamel by backing ring and continuous layer of enamel coat on inner surfaces of pipe being connected over entire area of weld seam. 4 cl, 4 dwg