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

FIELD: plastic metal working, namely processes for mounting tubes in tube plates of heat exchangers at using effect of local oriented plastic deforming of tube material. SUBSTANCE: method comprises steps of placing end portions of preliminarily prepared tube in openings of two tube plates, each opening having inner and outer annular grooves; fixing tube against its possible motion relative to tube plates and fastening it in openings of tube plates by expanding; realizing expanding process by two stages: at first stage filling volume of inner annular grooves of both tube plates with tube material in zone between tube plates at applying effort to inner surface of tube; at second stage loading tube ends by axial compression effort and initially filling volume of outer annular grooves of said openings with tube material. EFFECT: possibility for achieving desired operational characteristics of expanded joints without increasing efforts applied to inner surface of tube. 7 dwg