Investigation of residual stresses in a repair-welded rail head considering solid-state phase transformation

摘要

Repair welding for recovery from local damage of a rail head surface is known to cause high residual stress and can accelerate fatigue in the rail. This study examines repair-welded rails by applying experimental and numerical approaches. In the former approach, two newly manufactured rail specimens and four repair-welded rail specimens with two different weld depths were prepared, and their residual stresses were measured with a sectioning method. In the latter approach, a finite element repair welding simulation model was developed that adopted a prescribed temperature method with a moving block as an input heat source, and the thermal strain caused by the volume change due to solid-state phase transformation was considered. Overall, the residual stresses correlated well between the experimental and numerical approaches. The measured high compres-sive residual stress of — 290 MPa seems to be beneficial to prevent a crack initiation in the rail surface.