Causes of Rail Defects:
The origin and development of such cracks is due to:
- Material defects- At Manufacturing process Such as Cluster of nonmetallic inclusions, hydrogen flakes, rolling marks, guide marks etc
- Residual stresses induced during manufacture (cooling, rolling, gas pressing and straightening).
- Defects due to incorrect handling e.g. plastic deformation, scoring, denting, etc.
- Defects associated with faulty welding i.e. gas pores, lack of fusion, inclusions, cracks etc.
- Dynamic stresses caused by vertical and lateral loads particularly by vehicles with wheel flats or when the vehicle runs over poorly maintained rail joints etc.
- Excessive thermal stresses due to variation in rail temperature beyond specified limits