覆膜砂用铬矿砂AFS70-80 Chromite sand 70-140#
覆膜砂用铬矿砂AFS70-80 Chromite sand 70-140#适合做铸造制芯的芯砂材料。铬矿砂是一种烧结温度高、化学惰性、热传导性能优异、遇热膨胀小的耐火材料和铸造材料。铬矿砂AFS 70-80主要用于铸钢件和高锰钢铸件易粘砂部分的芯砂、浇注温度高的铸钢件合金铸钢件的覆膜砂等方面。
Chromite sand AFS70-80 is suitable as a core sand material for casting core making. Chromite sand is a refractory and casting material with high sintering temperature, chemical inertness, excellent thermal conductivity, and low thermal expansion. Foundry chromite sand AFS 70-80 is mainly used for core sand in the sand prone parts of steel castings and high manganese steel castings, as well as for coating sand in alloy steel castings with high pouring temperatures.
覆膜砂用铬矿砂AFS70-80 Chromite sand 70-140#的性能特点：
- 高熔点,烧结温度高
- 优异的热稳定性和化学稳定性
- 高密度，比重大
- 中等莫氏硬度5.5
- 热传导能力强
- 热膨胀系数低
The characteristics of Chromite sand AFS70-80:
1. High melting point, high sintering temperature2. Excellent thermal and chemical stability
3. High density, high density -
4. Medium Mohs hardness 5.5
5. Strong thermal conductivity
6. Low coefficient of thermal expansion
覆膜砂用铬矿砂AFS70-80 Chromite sand 70-140#的技术参数：
-
化学成分
| 化学成分 | 标准值 | 实测值 |
| Cr2O3 （三氧化二铬） | ≥ 46% | 46.43% |
| SiO2（二氧化硅） | ≤ 1.0% | 0.62 |
| FeO（氧化铁） | ≤ 26.5% | 25.62% |
| Cr：Fe （铬铁比） | ≥1.5：1 | 1.58 |
| MgO（氧化镁） | ≤ 10% | 9.56% |
| CaO（氧化钙） | ≤ 0.3% | 0.2% |
| Al2O3（三氧化二铝） | ≤ 15.5% | 15.26% |
| MnO（氧化锰） | ≤ 0.5% | 0.21% |
| TiO2（氧化钛） | ≤ 1.0% | 0.62% |
| P（磷） | ≤30 ppm | ≤30 ppm |
| S（硫） | ≤30 ppm | ≤30 ppm |
| L.O.I（灼减） | ≤0.5% | / |
2.物理性能：
| 成分Formula | (Fe,Mg) Cr2O4 |
| CAS号 | 1308-38-9 (for Cr2O3) |
| EINECS-No. | 2151609 (for Cr2O3) |
| 莫氏硬度（Mohs Hardness） | 5.5-6 |
| 熔点（Melting Point） | 2180 ℃ |
| 烧结温度（Sintering Point） | ＞1800℃ |
| 比重（Specific Gravity） | 4.0-4.8 g/cm3 |
| 堆积密度 (Bulk Density LPD) | 2.5-3 g/cm3 |
| 颜色（Color） | 亮黑色（Shiny black） |
| PH值（PH Value） | 7-9 |
| 导热系数（Thermal conductivity） | 0.63 W/M·K |
| 热膨胀率（Thermal Expansion Rate）（1000℃） | 0.6% |
| 酸耗值（Acid Demand Value ADV） | ≤ 5ML |
| 浑浊度（turbidity）(JTU) | ≤ 110 |
| 含泥量（Soil content） | ≤ 0.1% |
| 含水量（Moisture） | ≤ 0.1% |
铸造级铬矿砂的应用范围：
1. 大型厚壁型铸件铸造：铬矿砂配合砂型铸造、呋喃树脂自硬砂、水玻璃自硬砂等工艺，用于体积重量大的铸铁件和铸钢件，可以使铸件按既定的顺序进行冷却，有利于提高铸件内部的紧密度，增强铸件的强度。此外，对于使用硅砂的工艺，可在容易出现气孔、脉纹的关键部位，使用铬矿砂作为面砂代替硅砂，可以有效防止裂纹、气孔等铸造缺陷。2. 消失模铸造。在消失模铸造中，选用铬矿砂，可以防止石英砂铸造造成的夹砂、粘砂等缺陷。用于制造高铬铸钢、高锰钢材质的阀门、叶轮等铸件。
3. 壳型铸造：铬矿砂可用于壳型铸造中复杂部件的芯砂材料，制作砂芯。用于生产高精度、表面光滑的304，316不锈钢铸件和碳钢精密铸件等，可以有效防止铸件内腔的粘砂问题。
4. 砂型铸造：铬砂还可以用于砂型铸造，如型砂铸造、水玻璃自硬砂砂型铸造等，用于生产各种大中小型零件，如泵体、管道、阀门等。
5. 覆膜砂：细号的铬铁矿砂可以作为砂芯的材料用于树脂覆膜砂铸造。
Application：
1. Large scale thick walled casting: Chromite sand combined with sand casting, furan resin self hardening sand, water glass self hardening sand and other processes are used for large volume and weight cast iron and steel castings. It can cool the castings in a predetermined order, which is conducive to improving the internal tightness of the castings and enhancing their strength. In addition, for the process of using silica sand, chrome ore sand can be used as surface sand instead of silica sand in key areas where porosity and veins are prone to occur, which can effectively prevent casting defects such as cracks and porosity.2. Lost foam casting. In lost foam casting, using chrome sand can prevent defects such as sand inclusion and sticking caused by quartz sand casting. Used for manufacturing castings such as valves and impellers made of high chromium cast steel and high manganese steel materials.
3. Shell casting: Chromite sand can be used as a core sand material for complex components in shell casting, making sand cores. Used for producing high-precision, smooth surface 304316 stainless steel castings and carbon steel precision castings. It can effectively prevent the problem of sand sticking in the inner cavity of castings.
4. Sand casting: Chromite sand can also be used for sand casting, such as sand casting, water glass self hardening sand casting, etc., to produce various large, medium, and small parts, such as pump bodies, pipelines, valves, etc.
5. Resin Coated sand: Fine grained chromite sand can be used as the material for sand cores in resin coated sand casting.
覆膜砂用铬矿砂AFS70-80 Chromite sand 70-140#的粒度分布如下：
| 目数 | 占比 |
| +50mesh(300um) | 1.19% |
| +70mesh(212um) | 32.60% |
| +100mesh(150um) | 45.60% |
| +140mesh(106um) | 15.10% |
| +200mesh(75um) | 4.10% |
| +270mesh(53um) | 1.41% |
| 细度 | AFS 72.36 |
铬矿砂Chrome ore sand的其他型号：
| 目数 | AFS细度 | 颗粒范围 |
| 20-40目 | AFS25-30 | 0.4-0.8mm |
| 20-50目 | AFS30-35 | 0.3-0.8mm |
| 20-60目，20-70目，30-70目 | AFS35-40 | 0.2-0.6mm，0.25-0.65mm, 0.2-0.8mm，0.2-0.9mm |
| 40-70目 | AFS40-45 | 0.2-0.4mm |
| 50-100目 | AFS45-50,AFS45-55,AFS50-55 | 0.15-0.3mm，0.2-0.3mm |
| 70-140目 | AFS65-70,AFS70-75 | 0.1-0.2mm |
| 100-200目 | AFS80-90 | 0.075-0.15mm |
铬矿砂AFS细度目数对照表：
铸造级铬矿砂的生产和包装：
