FIELD: welding lengthwise seams of shells. SUBSTANCE: apparatus includes sizing rollers mounted with possibility of rotation on carrier. Rotation axes of rollers are arranged in plane normal relative to direction of shell feed. Said carrier in the form of two identical semiframes can control position of sizing rollers. Said semiframes rest upon common bridge. At least one of said semiframes may be positioned with the aid of servodrive mechanism. Position of several sizing rollers may be controlled in common. Said servodrive mechanism is provided with lead screw. Two guides with cross supports 777 are mounted coaxially onto said bridge. Said bridge is mounted in housing of machine with possibility of parallel arrangement relative to lengthwise axis of shell. Plate type part is secured to each semiframe. At least one roller for preliminarily sizing is rigidly secured to said part. EFFECT: accelerated alignment process of sizing apparatus in dependance upon sheet thickness and seam contours, enhanced quality of welded joints. 6 cl, 5 dwg
