China's Refractories

Abstract: The mullite-SiC castables for coke dry quenching (CDQ) furnace corbel pillar were prepared by taking mullite and silicon carbide as aggregates, silicon carbide powder, fused silica powder, α-Al₂O₃ powder and silica fume as matrix, calcium aluminate cement as binding system, and extraadding steel fibers to extend the CDQ furnace refractory life. The effects of steel fiber types (melt pumping meniscus, cut straight, wavy indentation, cold-drawn hook) and steel fiber extra-additions (0, 1%, 2%, 3% by volume) on the properties of mullite-SiC castables were investigated. Then the toughening mechanism of steel fiber in the castables was analyzed according to the load-displacement curves. The results show that: (1) the toughening effects of the melt pumping meniscus steel fiber with rough surface and cold-drawn hook steel fiber with strong anchoring effect with the matrix are better than those of cut straight steel fiber and wavy indentation steel fiber; (2) the suitable amount of steel fiber (less than 2%) in mullite-SiC castables not only significantly improves the mechanical properties, thermal shock resistance and wearing resistance, but also improves the fracture energy by 49.0% and slows the crack growth; (3) the bond strength and mechanical anchoring force between steel fiber and castable interface are key elements of steel fiber reinforced castables.

Key words: coke dry quenching, steel fiber, mullite-silicon carbide castable, toughening mechanism