NMJ-5 High-strength Wear-resistant Refractory Castable is a cost-effective, cement-based composite dry mortar specifically engineered for industrial applications with moderate mechanical wear and thermal stress. Manufactured through an automated production process, it combines high-strength aluminate cement, graded mineral admixtures, wear-resistant aggregates, and anti-cracking additives to deliver consistent durability. NMJ-5 is ideal for users seeking an economical solution for general-purpose wear zones without compromising structural integrity under heat.
Technical Specifications
| Parameter | Value |
|---|---|
| Al₂O₃ (%) ≥ | 70 |
| Bulk Density (g/cm³) ≥ | 2.6 |
| Cold Crushing Strength (MPa) ≥ | 110℃ × 24h: 751100℃ × 3h: 90 |
| Modulus of Rupture (MPa) ≥ | 1100℃ × 3h: 16 |
| Permanent Linear Change (1100℃ × 3h, %) | -0.3 ~ 0 |
| Room Temperature Wear Volume (cm³) ≤ | 8 |
Key Features
Economic Grade Performance: Cost-effective choice for areas exposed to moderate mechanical and thermal wear.
Reliable Compressive Strength: Provides solid load-bearing capability up to 90 MPa after high-temperature firing.
Thermal Stability: Maintains structural integrity under repeated thermal cycling.
Good Castability: Easy to install using common casting or vibrating methods.
Shrinkage Control: Stable volume with minimal linear change at service temperatures.
Typical Applications
Secondary or less abrasive zones in circulating fluidized bed (CFB) boilers
Ash hoppers, dust collector inlets, and flue walls
Protective layers in kiln back linings or air ducts
Lower wear parts of industrial furnaces
Backup linings behind premium castables
Production Details
NMJ-5 is manufactured using:
High-strength calcium aluminate cement
Selected refractory aggregates with proper grain gradation
Anti-cracking agents and dispersing additives
Automated mixing and moisture-proof packaging to ensure batch-to-batch consistency
All products undergo rigorous testing for strength, density, and wear resistance prior to shipment.
Packing and Shipping Details
Packaging: 25kg or 50kg kraft paper bags with inner moisture-proof lining
Bulk Packaging: Jumbo bags available for large-volume projects
Palletizing: Shrink-wrapped on heat-treated pallets for sea or land transport
Frequently Asked Questions (FAQ)
Q1: What is the recommended method of installation for these castables?
These castables are best applied using vibrating casting or manual pouring. Ensure the surface is clean and slightly moistened before application. Proper mixing with clean water (typically 5–7% by weight) is crucial to achieving the desired density and strength.
Q2: How long does the castable need to dry before being put into service?
After casting, it should be air-cured for 24 hours, followed by gradual heating (dry-out process) to remove moisture and prevent steam spalling. A controlled heating curve is necessary, especially for thicker sections.
Q3. Can these castables withstand high thermal cycling and abrasion?
Yes, all NMJ series products are engineered to resist both mechanical wear and thermal shock, making them suitable for applications involving fluctuating temperatures and material impact.
Q4: What’s the difference between the NMJ models?
The main differences lie in the alumina content, density, crushing strength, and wear resistance. Higher model numbers like NMJ-1 have greater strength and wear resistance, while lower numbers like NMJ-5 offer cost-effective solutions for less demanding environments.
Q5: Are custom formulations or pre-shaped blocks available?
Yes. Xintai provides customized castable formulations and precast shapes based on your specific operating conditions and installation needs. Please contact us for technical support or tailored solutions.
