The project aimed to develop a remanufacturing cell for rail wheels, including in-process and post-production inspection to ensure accuracy and integrity of the wheels. Aside from the practical implications, the project also needed to address a lack of industry standards for repaired wheels due to the safety-critical nature of the work.
TWI used submerged arc welding, as it was the only process that was able to deposit material quickly enough to maintain process pre-heat, with deposition occurring at ~12kg/hour with a maintained interpass temperature of 400°C. When tested, the deposit bead overlap factor gave a very smooth layer surface, although it was not possible to lay material onto radii on the inboard corner or flange and additional work is required to limit additional deposition to re-build an acceptable profile.
The manufacturing cell created was reconfigurable so that it could accommodate wheelsets of different diameters. Software was written to control the automation of the welding process, while being able to sample the weld current, volts and wire feed speed, weld speed (wheel rotation speed) at pre-set intervals to give a record of the weld.