Wear micromechanisms in mixer blades in the iron ore sinter manufacturing process

Increasing pig iron production has led to a shortage of refined raw materials, resulting in smaller iron ore, which complicates its direct use in blast furnaces. Sintering fines have emerged as a viable alternative, with intensive mixers potentially increasing sintering speed by 10–12%. However, the components of these mixers experience severe wear due to contact with abrasive particles. This study aims to identify the predominant wear mechanisms on mixer blades in an iron ore sinter plant and to develop a laboratory methodology to simulate these mechanisms. A method based on ASTM G65 was developed to reproduce the wear observed in the field accurately. Four materials were evaluated: high-chromium white cast iron (WCI), AISI 304 austenitic stainless steel, and two hard coatings according to DIN 8555 standards (E-10-UM-65 GRTZ and E-6-UM-60 R). These materials were characterized in terms of hardness, Vickers microhardness, microstructure, and wear mechanisms through scanning electron microscopy. Comparing field and laboratory results, the methodology proved effective in simulating the tribological system. WCI showed 303% better wear resistance than E-10-UM-65 GRTZ, while the other materials performed worse. Field tests revealed that the E-6-UM-60 R coating was ineffective, suffering early wear and exposing the substrate, leading to a high wear rate. Laboratory tests showed that AISI 304 stainless steel performed the worst, highlighting the difficulty of replicating real wear conditions. The study also found that hardness does not directly correlate with wear resistance, suggesting that microstructure plays a decisive role in material selection for this application.