NMJ-4 Castable offers a solid balance of performance and economy. With 75% Al₂O₃, it is suitable for less aggressive thermal zones. Its good strength and thermal shock resistance make it ideal for boilers and furnaces operating at medium temperatures.
Technical Specifications
| Item | Value |
|---|---|
| Al₂O₃ (%) ≥ | 75 |
| SiO₂ (%) ≤ | 19 |
| Bulk Density (g/cm³) ≥ | 2.75 |
| Cold Crushing Strength (MPa) | 80 (110℃×24h), 100 (1100℃×3h) |
| Modulus of Rupture (MPa) | 11 (110℃×24h), 12 (1100℃×3h) |
| Wear Loss at Room Temp (cc) ≤ | 6 |
| Thermal Shock Resistance | ≥ 25 times |
Key Features
Affordable refractory solution
Sufficient thermal stability for medium-temperature zones
Easy on-site installation
Compatible with steel & power industries
Typical Applications
Boilers
Kiln hoods
Lime shaft kilns
Heat exchangers
Production Details
Produced in batches with strict quality control, using medium-purity aggregates and water reducers to ensure smooth pouring and setting.
Packing and Shipping Details
25kg or 50kg moisture-proof bags, shrink-wrapped on pallets
Custom packaging available upon request
Delivery time: 15–30 working days after order confirmation
Frequently Asked Questions (FAQ)
Q1: What is Corundum Refractory Castable and what is it made of?
Corundum Refractory Castable is a high-performance unshaped refractory material primarily composed of α-alumina (Al₂O₃ ≥ 90%). It is formulated with high-purity fused or sintered corundum aggregates, fine powders, high-alumina cement, silica fume, and other additives. It is known for its excellent resistance to high temperatures, chemical corrosion, and thermal shock.
Q2: What is the maximum service temperature of Corundum Castable?
The material has a refractoriness exceeding 1800°C (3272°F) and can be used in working conditions with temperatures up to 1650–1750°C (3002–3182°F), depending on the furnace atmosphere and thermal load.
Q3. What should be considered during the installation of corundum castables?
Key installation points include:
Ensure the surface is clean and dry before casting.
Add water strictly according to the recommended ratio.
Mix thoroughly to a uniform consistency.
Use a vibrator to ensure proper compaction.
After casting, allow 24 hours of curing at room temperature.
Follow with a proper drying and heat-up schedule to remove residual moisture.
Avoid construction in temperatures below 5°C (41°F) or above 35°C (95°F).
Q4: In which industries and equipment is this product commonly used?
Corundum castables are widely used in industries such as:
Metallurgy: ladles, tundishes, steel-making furnaces
Cement and Lime: burner pipes, rotary kilns
Petrochemical: gasifiers, reformers
Glass & Ceramics: kiln roofs, burners
Power Generation: waste incinerators, boiler linings
Q5: Can you provide custom formulations or on-site support?
Yes. We offer customization services to meet specific application requirements. This includes adjusting aggregate sizes, flowability, setting time, and thermal shock resistance. Our technical team can also offer on-site support and guidance for installation and heating procedures.
