Method for Repairing Metallic Structure

Abstract

A rail repair method enables repair of rails and rail-like structures. A rail defect is initially identified and removed as contained within a volumetric material portion so as to form a contoured void while maintaining continuity of the rail opposite the void. A pre-formed insert is then placed into the void thereby effecting a rail-to-insert interface. Current is driven through the interface as force directs the insert against the rail. Resistance heat and pressure weld the insert to the rail. The flash welding aspects remove oxides and other impurities from the interface, and the forge welding aspects create a robust solid state weld. Excess material, whether flash, rail, or insert-based, is removed during the finishing processes to provide a virtually seamless rail repair. The solid state weld repair methodology may be used to repair any number of targeted metallic rail-like structures.

We claim: 
     
         1 . A method of repairing a metallic structure having first and second structural sections, the method comprising the steps of:
 a) identifying and locating a defect in the metallic structure;   b) removing a volumetric portion from the first structural section, the volumetric portion being inclusive of the defect;   c) exposing a void site in the first structural section via removal of the volumetric portion;   d) placing a pre-formed, solid state weld repair insert into the void site, thereby effecting a structure-to-insert interface; and   e) welding the metallic structure and insert at the structure-to-insert interface.   
     
     
         2 . The method of  claim 1  wherein the welding step comprises the step of driving current through the structure-to-insert interface. 
     
     
         3 . The method of  claim 1  comprising the step of maintaining continuity of the second structural section while exposing the void site. 
     
     
         4 . The method of  claim 3  wherein the volumetric portion has a first volume and the insert has a second volume greater in magnitude relative to the first volume. 
     
     
         5 . The method of  claim 4  comprising the step of forcing the insert against the metallic structure during the welding process. 
     
     
         6 . The method of  claim 5  comprising the step of removing oxides from the structure-to-insert interface during the welding process. 
     
     
         7 . The method of  claim 6  comprising the step of interdiffusing atomic structure from the metallic structure and insert across the structure-to-insert interface. 
     
     
         8 . The method of  claim 7  wherein the metallic structure is a rail. 
     
     
         9 . A method of repairing a current-conductive rail, which rail includes upper and lower rail sections, the method comprising the steps of:
 a) identifying and locating a defect in a first select rail section, the first select rail section being selected from the group consisting of the upper and lower rail sections;   b) removing a volumetric portion of the rail from the first select rail section, the volumetric portion being inclusive of the defect;   c) exposing a void site in the first select rail section via removal of the volumetric portion;   d) placing a pre-formed current-conductive insert into the void site, thereby effecting a rail-to-insert interface;   e) driving current through the rail-to-insert interface;   f) resistance-heating the rail and insert at the rail-to-insert interface via the driven current; and   g) welding the insert to the rail.   
     
     
         10 . The method of  claim 9  comprising the step of maintaining continuity of a second select rail section while exposing the void site, the second select rail section being selected from the group consisting of the upper and lower rail sections and being other than the first select rail section. 
     
     
         11 . The method of  claim 10  wherein the volumetric portion has a first volume and the insert has a second volume greater in magnitude relative to the first volume. 
     
     
         12 . The method of  claim 11  wherein the void site has a maximal transverse cross-sectional site area and the insert has a maximal transverse cross-sectional insert area, said insert area being greater in magnitude than said site area. 
     
     
         13 . The method of  claim 9  comprising the step of forcing the insert against the rail while driving current through the rail-to-insert interface. 
     
     
         14 . The method of  claim 9  comprising the step of removing oxides from the rail-to-insert interface. 
     
     
         15 . The method of  claim 13  comprising the step of interdiffusing atomic structure of the rail and insert across the rail-to-insert interface. 
     
     
         16 . The method of  claim 12  wherein said insert area is minimized relative to said site area. 
     
     
         17 . A method of repairing a current-conductive rail, said method comprising the steps of:
 a) removing a defect-inclusive, volumetric rail portion from said rail;   b) exposing a void site in said rail via removal of said rail portion;   c) placing a pre-formed current-conductive insert into the void site, thereby effecting a rail-to-insert interface; and   d) driving current through the rail-to-insert interface, thereby heating the rail and insert at the rail-to-insert interface and welding the insert to the rail.   
     
     
         18 . The method of  claim 17  comprising the step of maintaining continuity of the rail adjacent the void site while exposing the void site. 
     
     
         19 . The method of  claim 18  comprising the step of forcing the insert against the rail while driving current through the rail-to-insert interface, thereby
 a. removing oxides from the rail-to-insert interface; and 
 b. interdiffusing atomic structure of the rail and insert across the rail-to-insert interface. 
 
     
     
         20 . A rail repair method, the method comprising the steps of:
 forming a wedge-shaped repair insert having a pointed rail-opposing portion, the pointed rail-opposing portion having opposed planar insert surfaces, the opposed planar insert surfaces being substantially orthogonal to one another;   forming a wedge-shaped void in a rail, the void having a pointed, insert-receiving notch, the pointed insert-receiving notch having opposed planar void site surfaces, the void site surfaces being substantially orthogonal to one another;   inserting the wedge-shaped repair insert into the wedge-shaped void thereby effecting an angled rail-to-insert interface, the angled rail-to-insert interface thus having a 90 degree angle; and   driving current through the rail-to-insert interface for heating and welding the rail and insert at the rail-to-insert interface, the 90 degree angle for enhancing uniform heat distribution and minimizing material entrapment during the welding process.   
     
     
         21 . The method of  claim 20  wherein the current driving step comprises the steps of:
 preheating the rail and repair insert by driving a first range of current therethrough; 
 flashing the rail and repair insert by driving a second range of current therethrough; and 
 forging the rail and repair insert by driving a third range of current therethrough. 
 
     
     
         22 . The method of  claim 21  wherein the repair insert forming step comprises the added step of forming a beveled tip intermediate the opposed planar insert surfaces and the void forming step comprises the added step of forming a beveled valley intermediate the opposed planar void site surfaces, the beveled tip and beveled valley for further minimizing material entrapment during the welding process. 
     
     
         23 . A method of repairing a metallic structure, the method comprising the steps of:
 a) identifying and locating a defect in the metallic structure;   b) removing a volumetric portion from first and second structural sections of the metallic structure, the first structural section being integrally formed to the second structural section, the volumetric portion being inclusive of the defect;   c) exposing a void site in the first and second structural sections via removal of the volumetric portion;   d) placing a pre-formed, solid state weld repair insert into the void site, thereby effecting a structure-to-insert interface, the insert comprising an insert volume greater in magnitude than the removed volumetric portion; and   e) welding the metallic structure and insert at the structure-to-insert interface.   
     
     
         24 . The method of  claim 23  comprising the steps of forcing the insert toward the first and second structural sections for forging the insert to the metallic structure at the structure-to-insert interface while welding the metallic structure and insert at the structure-to-insert interface. 
     
     
         25 . The method of  claim 24  wherein the volumetric portion and insert volume are T-shaped in a first dimension, triangular in a second dimension, and rectangular in a third dimension. 
     
     
         26 . The method of  claim 25  wherein the T-shaped volumetric portion comprises rounded upper edging and the T-shaped insert volume comprises right-angled upper edging. 
     
     
         27 . The method of  claim 26  wherein the triangular volumetric portion and the insert volume each comprise a rounded interface vertex. 
     
     
         28 . A method of repairing a current-conductive rail, which rail includes upper and lower rail sections, the method comprising the steps of:
 a) identifying and locating a defect in a first select rail section, the first select rail section being selected from the group consisting of the upper and lower rail sections;   b) removing a volumetric portion of the rail from the first select rail section, the volumetric portion being inclusive of the defect;   c) exposing a void site in the first select rail section via removal of the volumetric portion;   d) placing a pre-formed current-conductive insert into the void site, thereby effecting a rail-to-insert interface, the insert comprising an insert volume greater in magnitude than the removed volumetric portion;   e) driving current through the rail-to-insert interface;   f) resistance-heating the rail and insert at the rail-to-insert interface via the driven current; and   g) welding the insert to the rail.   
     
     
         29 . The method of  claim 28  comprising the steps of forcing the insert toward the upper and lower rail sections for forging the insert to the rail at the rail-to-insert interface while welding the insert to the rail. 
     
     
         30 . The method of  claim 28  wherein the volumetric portion and insert volume are T-shaped in a first dimension, triangular in a second dimension, and rectangular in a third dimension. 
     
     
         31 . The method of  claim 30  wherein the T-shaped volumetric portion comprises rounded upper edging and the T-shaped insert volume comprises right-angled upper edging. 
     
     
         32 . The method of  claim 31  wherein the triangular volumetric portion and the insert volume each comprise a rounded interface vertex. 
     
     
         33 . A method of repairing a current-conductive rail, said method comprising the steps of:
 a) removing a defect-inclusive, volumetric rail portion from upper portions of said rail;   b) exposing a void site in said rail via removal of said rail portion;   c) placing a pre-formed current-conductive insert into the void site, thereby effecting a rail-to-insert interface, the insert comprising an insert volume greater in magnitude than the removed volumetric portion; and   d) driving current through the rail-to-insert interface, thereby heating the rail and insert at the rail-to-insert interface and welding the insert to the rail.   
     
     
         34 . The method of  claim 33  comprising the steps of forcing the insert toward the upper portions for forging the insert to the rail at the rail-to-insert interface while welding the insert to the rail. 
     
     
         35 . The method of  claim 33  wherein the volumetric portion and insert volume are T-shaped in a first dimension, triangular in a second dimension, and rectangular in a third dimension. 
     
     
         36 . The method of  claim 35  wherein the T-shaped volumetric portion comprises rounded upper edging and the T-shaped insert volume comprises right-angled upper edging. 
     
     
         37 . The method of  claim 36  wherein the triangular volumetric portion and the insert volume each comprise a rounded interface vertex. 
     
     
         38 . A rail repair method, the method comprising the steps of:
 forming a wedge-shaped repair insert, the insert being T-shaped in a first dimension, triangular in a second dimension, and rectangular in a third dimension, the triangular second dimension having a pointed rail-opposing portion, the pointed rail-opposing portion having opposed planar insert surfaces, the opposed planar insert surfaces being substantially orthogonal to one another;   forming a wedge-shaped void in a rail, the void being T-shaped in the first dimension, triangular in the second dimension, and rectangular in the third dimension, the void having a pointed, insert-receiving notch, the pointed insert-receiving notch having opposed planar void site surfaces, the void site surfaces being substantially orthogonal to one another;   inserting the wedge-shaped repair insert into the wedge-shaped void thereby effecting an angled rail-to-insert interface, the angled rail-to-insert interface thus having a 90 degree angle; and   driving current through the rail-to-insert interface for heating and welding the rail and insert at the rail-to-insert interface, the 90 degree angle for enhancing uniform heat distribution and minimizing material entrapment during the welding process.   
     
     
         39 . The method of  claim 38  comprising the steps of forcing the insert toward the rail for forging the insert to the rail at the rail-to-insert interface while welding the insert to the rail. 
     
     
         40 . The method of  claim 38  wherein the T-shaped dimension of the insert comprises right-angled upper edging, and the T-shaped dimension of the void comprises rounded upper edging. 
     
     
         41 . The method of  claim 40  wherein the triangular dimension of the insert and void each comprise a rounded interface vertex.