METHOD FOR OBTAINING HEAT-EXCHANGE TUBES WITH SHAPED ENDS Russian patent published in 2010 - IPC B21D53/08 B21D41/00 F28F1/00 

FIELD: metallurgy.

SUBSTANCE: radial crimping of tube end is performed with detachable matrix segments. Matrix has final and preliminary prints. Crimping is performed on a mandrel with shaping and working teeth by detachable matrix segments. At that, in preliminary matrix print on the shaping tooth of the mandrel there formed on the tube is external annular stiffness. Then matrix is opened and tube is moved in axial direction till it contacts the matrix edge shoulder. Annular constriction of tube end is performed after external annular stiffness by applying radial force to matrix segments. At the same time, there died is internal annular stiffness which restricts axial flow of tube material to matrix preliminary print. Then by mandrelling the tube with working tooth of the mandrel there formed is annular projection and end of the tube with thickened wall.

EFFECT: improving the quality of obtained items.

6 dwg