1、Chemical composition

2、Quality Indicators of Duoyuan Active Alumina Sand 

3、Characteristics of Duoyuan Active Alumina Sand

1.  High refractoriness and excellent thermal stability, effectively preventing defects such as sand adhesion, deformation, cracking, or fracture in sand cores, with good regenerability.
2. Low expansion coefficient. Adding a certain proportion of ceramic sand during core making can significantly reduce veining defects in casting internal cavities.
3. Rounded grain shape, which notably improves sand flowability, enhances core density, and reduces the risk of sand adhesion in casting cavities.
4. Low clay content, which allows for reduced resin addition within a certain range, lowering auxiliary material costs and minimizing the risk of porosity defects in castings.
5. Low impurity content (e.g., alkali metals, their oxides, and magnetic substances), effectively inhibiting sintering defects in sand cores after heating, preventing blockage in narrow areas of casting cavities, and reducing residual black sand in internal cavities.

4、Case Studies: Common Defects Associated with Specialty Sands    

Under the process conditions of cold cores or precoated sand hot cores, when making cores with special sands, common associated defects such as inner cavity sintering (blockage) and poor core collapsibility (black sand) often occur due to the influence of impurity components (alkaline metals and their oxides, other magnetic substances).

Duoyuan Active Alumina Sand can effectively inhibit the occurrence of associated defects such as sintering in the inner cavity of castings and poor collapsibility.