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

FIELD: plastic metal working, particularly processes for fastening tubes in tube openings of heat exchange apparatuses at using effect of localized directed plastic deformation of tube material. SUBSTANCE: method comprises steps of preliminarily calibrating tube end according to its outer diameter and profiling it along calibrated portion by reduction for forming portion with curvilinear generatrix turned towards tube axis; placing tube with minimum gap in tube opening having annular grooves; placing portion with curvilinear generatrix by cantilever fashion relative to outer edges of annular grooves; realizing tube fastening during two stages; at first stage initially fastening tube along distance from tube end until profiled portion; at second stage finally fastening tube again during two stages by applying deforming effort to tube portion with minimum diameter. It provides high-quality filling of volume of annular grooves of tube plate with tube material. EFFECT: enhanced operational characteristics of joint. 7 dwg