METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2002 - IPC

FIELD: plastic metal working, namely fastening tubes in tube plates. SUBSTANCE: method comprises steps of forming annular protrusion on outer surface of tube end; placing tube in tube opening having outer and inner annular grooves; matching annular protrusion of tube with outer annular groove; fixing tube against possible motion for further securing it to tube plate; applying compression effort to inner surface of tube at realizing successive stages of freely introducing said protrusion to annular groove for locally expanding joined parts; at local expanding deforming tube material by bending in zone between annular grooves; then plastically forming tube material in annular protrusion and finally fixing tube in annular grooves due to cross shift of tube material relative to annular protrusion. EFFECT: enhanced strength, closeness and corrosion resistance of tube-to-tube plate joints. 5 dwg