Why is HEVI chromite sand used as facing sand for steel castings?
Why is HEVI chromite sand used as the surface sand for steel castings?
The main reasons for choosing chromite sand as the surface sand for steel castings include its excellent physical and chemical properties, as well as its specific role in the casting process.
Chromite sand plays a vital role in steel castings, which is mainly reflected in the following aspects:
Preventing sand sticking: HEVI Chromite sand has a stable volume when heated and high thermal conductivity. When in contact with molten metal, it not only has a good effect of resisting alkaline slag, but also has the characteristics of solid phase sintering, which can well prevent the penetration of molten metal and avoid the occurrence of sand sticking defects. Increasing cooling rate: The thermal conductivity is much higher than that of silica sand, which can significantly increase the cooling rate of castings. In practical applications, it can play the role of an external chiller, which helps the castings to solidify quickly and reduce internal defects.
Refractory aggregate: HEVI Chromite sand can be used as a refractory aggregate for casting coatings after grinding, which can significantly improve the refractory performance of the coatings. This is especially important for steel castings that need to withstand high temperature environments.
Prevent thermal deformation: Adding an appropriate amount to the molding sand can be used to configure the surface sand of cast steel and pig iron, which helps to reasonably prevent thermal deformation welding defects and ensure the quality of castings.
Improve casting quality: The excellent physical and chemical properties of HEVI chromite sand enable castings to maintain good shape and dimensional stability during the molding process, reduce deformation and cracks, and thus significantly improve the overall quality of castings.
Chemcial data:
| Cr2O3 | SiO2 | FeO | CaO | MgO | Al2O3 | P | S | Cr/Fe |
| ≥46.0% | ≤1.0% | ≤26.5% | ≤0.30% | ≤10.0% | ≤15.5% | ≤0.003% | ≤0.003% | 1.55:1 |
Physical data:
| Bulk density | Volume density | colour | PH | calcined tempreture | smelting point |
| 2.5-3g/cm³ | 4.0～4.8g/cm3 | black | 7-9 | > 1800°C | 2180°C |
Package：1000kgs/jumb bag
Capacity：8000Tons/year
