METHOD FOR COMBINATION FASTENING OF TUBES IN TUBE WALLS Russian patent published in 2003 - IPC

FIELD: plastic metal working with use of mechanical rolling and welding. SUBSTANCE: method comprises steps of preliminarily shaping end of tube after special preparation of it in order to form end portion with two cylindrical zones and with transition cone between said zones; placing one end of tube into flared opening at minimum gap; arranging transition cone portion of tube outside opening of tube wall; then applying effort to inner surface of tube on cylindrical portion with less diameter of opening in order to provide expansion of cylindrical portion with large diameter of opening due to bending its generatrix relative to generatrix of opening of tube wall; expanding tube at applying to its inner surface compression effort; then fixing tube relative to walls of tube opening by welding. EFFECT: stable operational characteristics of rolled joints. 4 dwg