METHOD FOR SECURING TUBES IN TUBE WALLS Russian patent published in 1999 - IPC

FIELD: plastic metal working, namely processes for securing tubes with profiled end portions shaped by localized directed yielding of tube material in opening of tube wall of heat exchange apparatus. SUBSTANCE: annular trapezoidal cross section protrusions are made on outer surface of tube end portions. Then tube is arranged in tube wall opening with annular rectangular cross section grooves in such a way that to provide coincidence of said protrusions and grooves. Tube is fixed against possible motion and then it is secured to wall by applying compression effort at side of tube inner surface. Annular protrusions of tube are made at initially applying axial compression effort to tube end in its portion arranged at side of tube inner surface for pressing tube material radially in order to preliminarily form protrusions. Said protrusions are finally formed due to applying deforming effort to tube end on its portion at side of tube outer surface in such a way that to combine radial pressing out of tube material and simultaneous shifting of pressed material relative to outer surface of tube. EFFECT: lowered cost price of tube. 4 dwg