Fatigue failure of a flash butt welded rail.

• Autor(a) principal: Godefroid, Leonardo Barbosa
• Data de Publicação: 2014
• Outros Autores: Faria, Geraldo Lúcio de, Cândido, Luiz Cláudio, Viana, Thiago Gomes
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFOP
• Texto Completo: http://www.repositorio.ufop.br/handle/123456789/5506; https://doi.org/10.1016/j.mspro.2014.06.306
• topic: Rails; Flash butt welding; Cracking

Medium carbon steel rails are commonly jointed by means of a flash butt welding procedure. To ensure an adequate service life for the structural component commonly subjected to fatigue loading, a rigorous quality control should be performed, both in welding parameters and in the surface quality of the welded joint. This work investigated the cause of a recurrent failure in a railway, with cracking always initiated in the rail in the region of the welded joint. All standard procedures of failure analysis were applied, with a careful assessment of the material characteristics and the fractured surface. It was concluded that fatigue cracks initiated near the weld bead and spread in a brittle mode, leading to premature fracture of the material. An in-depth analysis of the early cracks showed that the surface finishing of the weld bead was not appropriate, generating undesirable stress concentration. A recommendation to change the procedure of surface finishing of welded joint was held, aiming to decrease the number of accidents on the railway line.