การศึกษาผลกระทบจากการเชื่อมซ่อมซ้ำหัวรางตะเฆ่

Casting austenitic manganese steel turnout frogs are critical part in trackwork components. Because of subject to high impact forces and wear rate is higher than normal running surface, the effective repair method is required for restore the profile of the rail that can extend the service life of frog will improve the safety and efficiency of rail operation. Repair welding is challenging because it requires rapid cooling rate, low heat input and minimize heating of the base material to retain high toughness and wear resistance properties. In this project, a new gas metal arc welding (GMAW) with cold metal transfer (CMT) technique was proposed to reduce heat input, increase productivity, and improve weld quality of repair. This reduction minimized heating of these components during welding and minimized local temperature adjacent to deposited weld bead. The multiple times of welding repair on running surface up to four-time repeated welding repairs were simulated, and repair area were evaluated with radiographic testing, impact testing, hardness mapping and microstructure characterization after welding allows the wear surfaces to transform into a hard, tough structure through deformation twinning, particle precipitation, and phase change.