Casting Ceramic Sand Properties and Usage
Casting Ceramic sand, also known as fused ceramsite sand, is a high-quality substitute for silica sand. It is a non-silica-based artificial sand. It is suitable for various casting methods such as V-method, VRH, lost foam casting, investment casting, resin-coated sand, no-bake sand, etc. Casting ceramic sand is suitable for the production of various binders. Ceramic casting sand works well for castings of steel, iron, non-ferrous metal, etc. It is easy to clean the sand and the sand mixing process is simple and convenient. For most castings, the coating can be omitted, especially suitable for making high-quality castings.
Microscopic photo of Casting Ceramic sand(AFS60):
Silica sand is easy to get and low cost. However, its drawbacks are also quite obvious. Firstly, the expansion coefficient of silica sand is high and leads to low casting accuracy. Secondly, silica-casting sand will make severe sand stick on the surface of the casting. It’s difficult to clean the sand from castings. The reason for those drawbacks is that silica sand generates various homogeneous and heterogeneous crystals at different temperatures. That results in significant volume changes. The refractoriness of silica casting sand is low(about 1400-1700℃), and some parts of casting such as holes, grooves, and areas with concentrated hot spots may have severe sand adhesion, making cleaning very difficult. The above shortcomings are particularly serious in the production of large steel castings.
Casting ceramic sand can overcome these shortcomings and greatly improve the quality of castings. Ceramic casting sand is made from high-quality bauxite through processes such as calcination, electric melting, granulation, and screening.
>>Physical and Chemical Properties of Casting Ceramic sand
| Refractoriness | ≥1800 ℃ |
| Specific gravity: | 3.4g/cm3 |
| Bulk density(LPD): | 1.95-2.05 g/cm3 |
| Color: | black brown |
| Grit shape: | spherical Ball |
| Thermal expansion coefficient | 6×10-6 /℃(20-1000℃) |
| Thermal conductivity | 0.698W/M.K(1200℃) |
| Thermal expansion ratio | 0.13% |
| Acid consumption | ≤3mL/g |
| Angularity | ≤1.1 |
| AL2O3 | 70-75% |
| SiO2 | 8-20% |
| Fe2O3 | ≤3% |
| TiO2 | ≤3.5% |
| CaO | ≤0.45% |
| MgO | ≤0.35% |
| K2O | ≤0.33% |
| Na2O | ≤0.08% |
>>Characteristics of Casting Ceramic Sand
1. The coefficient of thermal expansion is small, and the performance can be comparable to that of zircon sand. When used to prepare molding sand, castings will not produce expansion defects.
2. The sand particles are spherical in shape, with good fluidity, easy compaction, and good breathability.
3. The surface is smooth and the structure is dense, allowing the resin binder to cover evenly.
4. Casting ceramic sand is a neutral material that can be used as both acid and alkali binders.
5. Good recycling and regeneration performance, high cost-effectiveness. Compared with chrome iron ore sand and zircon sand, its price is only 25-50% of that of zircon sand and chrome iron ore sand. Meanwhile, due to the spherical shape of sand particles and their small surface area, the amount of resin added can be reduced by 30-50%. The amount of water glass added is ≤ 4%. This also reduces casting defects caused by adhesives and improves the yield of castings.
6. High fire resistance and easy to shake out after casting cooling.
7. High thermal conductivity, good stability, and no cracking
>>Casting ceramic sand Usages:
1. Resin-coated sand, shaping, shell molding, and core making.
2. Shell casting instead of precision casting process to produce precision cast steel small parts.
3. Cold core box resin sand process to produce automotive castings such as cylinder blocks, cylinder heads, exhaust pipes, etc.
4. Casting ceramic sand is suitable for the entire casting line with Alkaline phenolic resin sand process, Furan resin sand process, modified sodium silicate sand process, Bonnie resin sand process, etc.
5. Water glass sand process for large steel castings.
6. Lost foam casting process as filling sand.
7. Filling sand for V-method casting.
8. Ladle drainage sand-filling materials.
9. 3D printing processes.
10. Ceramic casting sand with fine grit for casting coatings and lost foam coatings