METHOD FOR MECHANICAL REMOVAL OF TENSILE STRESSES IN A TUBE SHICH HAS BEEN EXPANDED IN A SUPPORT

摘要

Mechanical removal of tensile stress in a tube(1) having a radially expanded zone(4) and a radially non-expanded zone(5) comprises contacting the transition zone(6) with an expansion device(7) and applying diametral deformation of controlled intensity and direction. The method is esp. suitable for treating heat exchanger assemblies since the stress reduction produced reduces the risk of crack formation under corrosive conditions. The tube(1) deformation is pref. produced by introducing fluid under pressure into the tube interior.