Brazing of sintered iron to mild steel for wind turbine brake pad applications

Abstract

The demand for renewable energy has prompted an increasing interest in wind turbine technology, where efficient and reliable brake systems play a critical role in ensuring safety and performance. This study investigates the brazing process to join sintered iron to mild steel for wind turbine brake pad applications. The sintered iron components were synthesized using iron powder with an average particle size of 30 µm and sintered at different temperatures under vacuum and hydrogen environments. Eutectic CuSil with added copper powder was employed as the brazing alloy to join the sintered iron and mild steel. The brazed joints were characterized using various techniques, including optical microscope, scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffractometer, and microhardness tester. The microhardness of the sintered iron was ∼580 HV for SICV and ∼620 HV for SICH due to oxide formation during processing. The microhardness of the braze joint was 72 HV, and mild steel exhibited 110 HV. Tribological testing was performed to analyze the wear behavior of the sintered iron specimens (before and after the brazing). SICH specimens showed a wear rate of 1.3 × 10⁻⁴ g/Nm, and SICV specimens exhibited a wear rate of 5.3 × 10⁻⁴ g/Nm. Brazing the sintered iron component (SICV) with mild steel using eutectic CuSil and a modified assembly method in a vacuum successfully achieved a satisfactory joint with improved wear resistance. The study emphasizes the potential of this approach for efficient and reliable brake pad fabrication for wind turbines.