PIPE LINE JOINT

FIELD: threaded joints of pipe lines with cut-in ring. SUBSTANCE: joint includes pipe union with inner sealing surface, union nut with pressure surface, cut-in ring with working edge in front portion whose outer and inner surfaces are curvilinear forming varying gap over entire length of cut-in ring relative to pipe line. Rear portion of cut-in ring has closing edge. Free end of pipe line with union nut and cut-in ring is inserted in pipe union till it gets in contact with bead. When union nut is screwed on pipe union, cut-in starts shifting axially and gets crimped radially cutting in body of pipe line by working edge and closing edge both in working and non-working states in four zones: in zone of cutting of working edge in pipe line; in zone of contact of surfaces of cut-in ring with pipe union; in zone of contact of surfaces of rear portion of cut-in ring and union nut and in zone of cutting of closing edge into pipe line. Entire volume of cut-in ring works as spring accumulating potential energy in mounting and providing for required axial and radial forces in pipe line both with and without pressure. Cutting-in of working edge and closing edge combine cut-in ring, union nut, pipe union and section of pipe line bounded by these edges in single compensation system which coordinates plastic-elastic deformation of this section of pipe line end elastic deformation of cut-in ring at rise of loads. EFFECT: ease of mounting the joint. 5 cl, 2 dwgo