METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2001 - IPC

FIELD: plastic metal working, possibly securing tubes to tube plates of heat exchange apparatuses at using effect of localized oriented plastic deformation of tube material. SUBSTANCE: method comprises steps of crimping end portions of tube; placing one tube end into die parting along generatrix and having inner and outer annular trapezoidal cross section grooves; fixing tube against axial motion and forming annular protrusions on outer surface of its end portion; placing tube in opening of tube plate having rectangular cross section annular grooves; matching annular protrusions of tube with annular grooves of tube opening; fixing tube against possible motion and fastening it in tube opening due to applying compression effort, for example by rolling, to inner surface of tube; reducing tube end with different deformation degree along said end for forming two portions; arranging one portion of tube end subjected to higher deformation at side of tube end surface; at placing tube in die opening, arranging tube end portion reduced with less deformation in front of inner annular groove. EFFECT: improved corrosion resistance of tube joint. 6 dwg