Microstructure, Tensile, and Low-Stress Abrasive Wear Properties of a New High Silicon Dual-Phase Cast Steel

A dual-phase cast steel with high silicon content has been developed to resist low-stress abrasive wear. The alloy is composed of Fe–0.3C–2.5Si–0.5Cr–0.3Mo–0.1Nb, and the Y block was produced using an investment casting process with an induction melting furnace. Following casting, the block was homogenized and subjected to intercritical annealing heat treatments at 825, 850, and 875 °C before being tempered at 350 °C. The microstructure of the specimens was studied by using optical (OM) and scanning electron microscopy equipped with image analysis software and an energy-dispersive X-ray spectroscopy analyzer. Mechanical properties were evaluated using Vickers hardness and tensile tests at room temperature. The tribological behavior of the specimens was determined using the pin-on-disk wear test method with abrasive paper at a force of 20 N (0.6 MPa). The results showed that the microstructure of the intercritical annealed steels consisted of polygonal and acicular ferrites and tempered martensite accompanied by niobium carbide. The martensite volume fraction, hardness, and yield strength increased with increasing IA temperatures, but the tensile strength remained relatively stable. Additionally, the tribological investigation indicated that the optimal wear resistance was achieved at 850 °C, and micro-cutting was the primary wear mechanism.