METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2000 - IPC

FIELD: plastic metal working, namely processes for securing tubes to tube plates of heat exchange apparatuses with use of effect of localized directed plastic deforming of tube material. SUBSTANCE: method comprises steps of making annular trapezoidal cross section protrusions on outer surfaces of tube end portions; placing tube into tube plate opening with annular rectangular cross section grooves; coinciding annular protrusions of tube with annular grooves of tube plate opening; fixing tube against its possible motion for further securing it to tube plate by applying compression effort to inner surface of tube; making along edges of annular grooves annular triangular cross section recesses with apexes not laying in plane of opening of tube plate; securing tube by filling annular grooves at condition of elastic deformation of tube plate material according to arrangement of annular grooves in their cross section. EFFECT: enhanced strength and compactness characteristics of rolled joints. 4 dwg