Advances in rail weld life extension procedures

摘要

Transportation Technology Center, Inc., (TTCI) is currently evaluating methods to improve the performance of rail welds. Among the strategies being investigated is a post-weld heat treatment that uses manual welding. With this approach, a high-hardness welding electrode is used to deposit a weld bead covering the softest portion of the heat-affected zone (HAZ) of the primary rail weld. This treatment is applied soon after completing the primary weld so that a second preheat is not required. The technique, termed HAZ Overlay Treatment (HAZOT), has been applied to treat standard and head alloyed thermite welds. Tests are underway to evaluate the effectiveness of HAZOT in revenue service. Other ongoing tests at the Facility for Accelerated Service Testing (FAST) include induction heat-treated electric flash-butt welds, HAZOT electric flash-butt welds and full-section alloy thermite welds.