FLASH BUTT WEDGE REPAIR OF WELD HEAD DEFECTS

摘要

Rail up time is critical to the success of a railroad and its customers. Head defects in rail can cause a loss of rail up time and typically requires the replacement of the affected area with a rail plug. A new approach for the repair of head defects has been developed which appears to exceed industry standards for performance called flash butt wedge repair. This welding repair method differs from other repair methods by using flash butt welding to place a wedge of actual rail material into a slot which was cut out of the rail to eliminate the defective section in the head. Testing of these welded joints shows a minimal heat-affected zone (HAZ) and lack of any pores, cracks, or solidification structure. These features allow the repaired area to perform much the same as parent metal rail. The repair method has been tested to insure that it exceeds both AREMA weld specifications and AWS rail welding specifications. The rolling load test of a flash butt wedge weld showed no erratic wear patterns or any signs of crack initiation.The repair can be completed in less than 45 minutes using a mobile welding truck. The rail is not fully severed only a small section of the head is removed thus eliminating any potential for change in the neutral rail temperature. The final repair area hardness can be matched to the parent rail with simple process changes. Currently, flash butt wedge repairs are being tested in service on heavy haul lines and at the TTCI FAST / HAL test loop for further analysis.