Abstract: The invention is a metal tube such as a heat exchanger tube which has been treated by in situ electrodeposition to repair one or more degraded sections. The repaired metal tube section has an electroformed structural layer which has an ultrafine grain microstructure of sufficient thickness to restore the degraded section at least to its original mechanical specifications.

Abstract: A process for repairing degraded sections of metal tubes, such as heat exchanger tubes, by in situ electroforming utilizes a probe containing an electrode. The probe is movable through the tube to the site of degradation and is sealed in place, thereby creating an electrochemical cell. Electrolyte flows from a reservoir through the cell and a structural layer of metal is deposited on the tube using a pulsed direct current and a duty cycle of 10-60%. The metal layer so formed possesses an ultrafine grain size preferably with a highly twinned microcrystalline structure giving the layer excellent mechanical properties.

Abstract: A process for repairing degraded sections of metal tubes, such as heat exchanger tubes, by in situ electroforming utilized a flexible probe containing an electrode. The probe is movable through the tube to the site of degradation and is sealed in place, thereby creating an electrochemical cell. Electrolyte flows from a reservoir through the cell and a structural layer of metal is deposited on the tube using a pulsed direct current and a duty cycle of 10-40%. The metal layer so formed possesses an ultrafine grain size preferably with a highly twinned microcrystalline structure giving the layer excellent mechanical properties.