Interfacial Reaction Behavior Between a Novel Chromite-ZrO2-SiO2 Mixed Sand and 13Cr9Mo1VNb Steel

Burn-on sand defects have consistently posed challenges to the quality and acceptance rate of sand-cast 13Cr9Mo1VNb steel castings. The interfacial behavior between the steel and a novel mixed sand composed of chromite, zircon and silica was investigated. A comparison was also conducted to evaluate the effects of pure mineral sands The impact of different mixed sands on burn-on defects and their formation mechanisms were analyzed. The results demonstrated that the liquid phase content in the sintered sand plays a crucial role in effectively eliminating burn-on defects. The mixed sand containing 15 pct zircon sand and 10 pct silica sand significantly reduces burn-on sand defects due to its high liquid phase content (about 34 pct), increased viscosity, and lower surface tension. Chromite/zircon and chromite/silica mixed sands are unsuitable for steel primarily because their low liquid phase content prevents the adhesive layer from separating effectively from the steel. Under solidification shrinkage, the reaction layer with a high liquid phase content fractures. The interfacial tension between the liquid phase and the steel has minimal impact on their separation. Therefore, The mixed sand containing 15 pct zircon sand and 10 pct silica is expected to be a promising mold material for reducing burn-on defects.