Analysis of factors affecting fractures of rails welded by alumino-thermic welding

On Latvian Railway the use of the alumino-thermic welding is widespread using the Elektro-Thermit Company technology. Today it is a basic method for rail joints on railway switches. The analysis of the metal structure in the thermic welding and in the thermic welded zone of rails showed that the weld metal had inclusions small pores and nonmetallics. Pores and nonmetallics are not reduce hardness but it is concentrators of stresses and sources of cracks development.