An improved flanged tube assembly with insert-reinforced tube flanges to prevent tube flange deformation and leakage when subjected to high compressive forces as well as sustained high-temperature procedures. The flange inserts are configured to form the flange portion of a flanged tube, or configured to provide structural support to the portions of the flange integral to the associated tube. The inserts may be metallic or polymer based and formed with various structural features to create a mechanical lock between the insert and the material used to make the tube/flange assembly. The inserts can be incorporated into the tube flanges so as to provide the desired support without being exposed to any fluids and/or gases that may flow through the reinforced tube/flange assemblies.