The disclosure provides a method for protecting a tube of a heat exchanger. The method includes inserting at least one portion of a non-ferrous tube into a hole of a tube sheet of the heat exchanger. The at least one portion of the non-ferrous tube is then rolled to radially expand the at least one portion. The at least one portion expands and forms a seal with the hole. A sleeve is then affixed onto an inner surface corresponding to the at least one portion of the non-ferrous tube.