A flange joint assembly having first and second attachment flanges are associated with first and second tubes through an interengagement of the ends of the tubes between an inner annulus and an annular corrugation which are inwardly of an attachment plate. The annulus and corrugation with the interengaged tube end are flared outwardly to interlock the components. The tube also includes an outwardly tapered section adjacent to the end. A tubular insert having inwardly tapered outer surfaces extending to each end from a midsection is positioned within the tapered portions of two axially abutting tubes. Fasteners draw the attachment flanges together to complete the assembly.