Per: Luiz felipe bauri (departamento de engenharia metalúrgica e de materiais, universidade de são paulo), Dany michell andrade centeno (dEPARTAMENTO DE ENGENHARIA METALÚRGICA E DE MATERIAIS, UNIVERSIDADE DE SÃO PAULO), Mariana moreno rodrigues (DEPARTAMENTO DE ENGENHARIA de materiais, UNIVERSIDADE FEDERAL DE SANTA CATARINA CAMPUS BLUMENAU), Luiz henrique dias ALVES (Engenharia Mecânica, Universidade Federal de Juiz de Fora), hélio goldenstein (dEPARTAMENTO DE ENGENHARIA METALÚRGICA E DE MATERIAIS, UNIVERSIDADE DE SÃO PAULO)
Abstract:
The influence of two sets of welding parameters on the microstructural evolution and mechanical properties of eutectoid and hypereutectoid rails during flash butt welding is investigated. It is shown that in the heat-affected zone (HAZ) a gradient microstructure is formed because of a thermal and strain gradient. The pearlite colonies decrease from the welding seam (WS) to the coarse-grained zone. Perlite colonies with proeutectoid ferrite at the prior austenite grain boundary are observed near the WS, while the pearlite presents a partially spheroidization in the region of partial austenitization. Despite the two different sets of welding parameter, tensile tests of samples that include the welding have shown rupture in the region of partial austenitization. The microhardness profile for the two welding conditions is consistent, detailing the valleys of the softened zone and the peaks in the hardened zone adjacent to the weld. Therefore, the results allow to understand the influence of the welding parameters in the steel microstructure, with emphasis on the morphological alterations of perlite.