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

FIELD: plastic metal working, possibly formation of combined rolled joints of tubes with tube plates of heat exchanging apparatuses. SUBSTANCE: method comprises steps of calibrating tube end according to its outer diameter along portion whose length exceeds thickness of tube plate; reducing part of calibrated portion of tube end for forming annular rigidity portion in the form of truncated cone; placing one end of tube in opening of tube plate in such a way that to arrange annular rigidity portion in plane of inner plate; placing tube end over front surface of tube plate; fixing tube against its possible motion; then performing first stage of tube rolling out by means of rollers for mechanical rolling out; providing out-of-contact deformation in radial direction of annular rigidity portion and forming annular tightness portion between inner edge of tube opening of tube plate and annular rigidity portion; welding tube to tube plate and realizing second stage of rolling out. EFFECT: enhanced corrosion resistance and other operational characteristics of combined joints. 9 dwg