Abstract: Combined with the commonly used process technology of expansion connection of heat exchange tube joint and using stainless steel S30403 as the material of tube and tube sheet, the mechanical expansion and hydraulic expansion of slotted structure are simulated numerically by the finite element method respectively. And the deformation mechanism and residual contact pressure distribution of the two processes are studied. The expansion depth and pullingout force are taken as the main evaluation indexes to analyze the effects of slotting size, set expansion on mechanical expansion and pressure on hydraulic. And comparative analysis is also conducted. These provide a basis for the preparation of heat exchanger standards and the parameters setting in expansion process.

Key words: union pipe joint, finite element method/FEM, residual contact pressure, expanded depth, pulling-out force