Estudo de caso: análise de falha prematura de um eixo de pinhão com aplicação em redutores de turbina eólica

Abstract

Failure analysis in steels consists of several stages, in which different analyses are involved. This paper presents a complete failure analysis of a pinion made of 18CrNiMo7-6 steel, whose application is in wind turbines, which presented cracks after the heat treatment process. The study shows some points of improvement in the process to avoid crack nucleation and propagation, as it occurred. For this purpose, analyses were performed via stereoscopy, optical microscopy, Vickers hardness, scanning electron microscopy and X-ray diffraction. The results showed that the gas carburizing process used in the tool caused intergranular oxidation in the center hole, which led to embrittlement in the region. Finally, it was seen that it would be ideal to protect the tool fitting area during the carburizing process, carburizing only its working area.