METHOD OF AND DEVICE FOR MAKING OF PIPES BY LASER WELDING OF LONGITUDINAL SEAMS Russian patent published in 1998 - IPC

FIELD: mechanical engineering; welding of pipes. SUBSTANCE: method comes to forming tubular blank 1 form strip 2 by bending its edges relative to symmetry plane 4 with simultaneously moving strip 2 in direction of its longitudinal axis. Edges of tubular blank 1 are moved to each other till they meet in plane 5. Laser beam 6 is directed along symmetry plane to point of edge alignment at acute angle to longitudinal axis. When shaping tubular blank 1, it is made elliptical in cross section, one axis of cross section being aligned with symmetry plane. Simultaneously tubular blank 1 is bent in longitudinal direction along arc to make it acquire a view of sector of torus with elliptical shape in cross section before alignment plane 5 and with longitudinal slot of wall. Laser source 15 has focusing system 16. Stands 17, 18, 19, 20 of moulding mill are made of shaped rollers 21. Welding stand is furnished with rolls. Shaped rollers 21 of stands 17, 18, 19, 20 are installed over arc and are made for bending tubular blank 1 along longitudinal axis so that tubular blank 1 coming out of stand 20 has shape of sector of torus with elliptical cross section and longitudinal slot in wall. Rolls of welding stand are installed for clamping tubular blank 1 in alignment plane 5. EFFECT: enhanced quality of welding joint, simplified design of device. 13 cl, 10 dwg