Method for repairing defects in a metallic substrate using welding

A method for repairing a void in a metallic substrate using welding, the substrate having a first surface and a second surface, wherein the void extends from the substrate first surface to the substrate second surface, the method comprising;

• a) placing a consumable filler slug in contact with the void;
• b) transmitting electrical current substantially uniformly from a first electrode to a second electrode for a period, thereby substantially symmetrically resistively heating the consumable filler slug and the metallic substrate resulting in coalescence in a substantially liquid pool that substantially fills the void, the first electrode and the second electrode applying pressure to the substantially liquid pool, wherein the consumable filler slug includes a first slut section and a second slug section, the first slug section having a retaining lip configured to be in contact with the substrate first surface and the second slug section having a retaining lip configured to be in contact wit the substrate second surface such that as current passes from the first electrode to the second electrode and resistively heats the first slug section and the second slug section a portion of each retaining lip coalesces into the pool and a portion of each retaining lip remains solid to constrain flow of the pool;
• c) cooling the substantially liquid pool to solidification under the pressure of the first electrode and the second electrode producing a repaired metallic substrate;
• d) removing the first electrode and the second electrode from contact with the repaired metallic substrate;
• and
• e) removing excess consumable filler slug material so that the surface of the repaired void is substantially consistent with the level of the adjoining substrate surface.

A method for repairing a defect that is a substantially cylindrically shaped void in a metallic substrate using welding, the substrate having a first surface and a second surface, and the void extending from the first surface to the second surface, the method comprising:

• a) placing a substantially cylindrical consumable filler slug in the void and applying a first sacrificial retainer on the first surface and a second sacrificial retainer on the second surface such that the first sacrificial retainer and the second sacrificial retainer cover the void and the consumable filler slug;
• b) transmitting electrical current substantially uniformly from a first electrode to a second electrode for a period of less than approximately 200 milliseconds while applying pressure to the first sacrificial retainer and the second sacrificial retainer, thereby substantially symmetrically resistively heating the first sacrificial retainer, the consumable filler slug, the metallic substrate, and the second sacrificial retainer resulting in coalescence of a portion of the first sacrificial retainer, the consumable filler slug, a portion of the substrate, and a portion of the second sacrificial retainer in a substantially liquid pool that substantially fills the void while being retained by the first sacrificial retainer and the second sacrificial retainer;
• c) cooling the substantially liquid pool to solidification under the pressure of the first electrode and the second electrode producing a repaired metallic substrate such that less than approximately 5% of the heat input to the consumable filler slug and the metallic substrate by the transmission of the current remains in the repaired metallic substrate and the repaired metallic substrate is substantially free of distortion;
• d) removing the first electrode and the second electrode from contact with the first sacrificial retainer and the second sacrificial retainer;
• and
• e) removing excess consumable filler slug material so that the surface of the repaired defect is substantially consistent with the level of the adjoining substrate surface.