Fused AZS bricks are produced through a high-temperature fusion casting process, where precisely controlled proportions of Al₂O₃ (alumina), ZrO₂ (zirconia), and SiO₂ (silica) are melted and cast into dense refractory blocks.
Unlike sintered refractory bricks, fused AZS bricks feature:
Extremely low porosity
Dense microstructure
Superior resistance to glass penetration
Stable performance at temperatures up to 1550–1600°C
（1）Exceptional corrosion resistance against molten glass, slags, and chemical media
（2）High ZrO₂ content (33-41%) for superior high-temperature stability (up to 1800℃ continuous service)
（3）Dense fused cast structure with low porosity (≤3%) and high bulk density (3.6-3.8 g/cm³)
（4）Strong wear resistance to prolong service life in high-traffic industrial applications
（5）Non-toxic and environmentally friendly, compliant with global refractory safety standards
（1）Glass furnace pool walls, feeder channels, and spout linings
（2）Chemical melting reactor linings and molten salt crucible linings
（3）Metallurgical ladle linings and secondary refining furnace components
（4）Special high-temperature furnace linings (ceramic sintering, electronic component annealing)
（5）Tin bath linings for float glass production lines
（6）Corrosion-resistant linings for acid-alkali high-temperature pipelines and valves
| Item | Fused Cast AZS Brick | AZS33 | AZS36 | AZS41 |
| Chemical Composition (%) | Al₂O₃ | ≥50.00 | ≥49.00 | ≥45.00 |
| ZrO₂ | ≥32.50 | ≥35.50 | ≥40.50 | |
| SiO₂ | ≤15.00 | ≤13.50 | ≤12.50 | |
| Na₂O + K₂O | ≤1.30 | ≤1.35 | ≤1.30 | |
| Volume Density (g/cm³) | ≥3.75 | ≥3.85 | ≥4.00 | |
| Apparent Porosity (%) | ≤1.2 | ≤1.0 | ≤1.2 | |
| Cold Crushing Strength (MPa) | ≥200 | ≥200 | ≥200 | |
| Exudation Temperature of Glass Phase (°C) | ≥1400 | ≥1400 | ≥1410 | |
| Bubble Separation Ratio (1300°C × 10h) | (%) | ≤1.2 | ≤1.0 | ≤1.0 |
| Anti-corrosion Rate of Glass Liquid (1500°C × 36h) | (mm/24h) | ≤1.4 | ≤1.3 | ≤1.2 |
| Bulk Density (g/cm³) | Ordinary Casting PT (RN / RC / N) | ≥3.55 | ≥3.55 | ≥3.70 |
| No Shrinking Casting ZWS (RR / EVF / EC / ENC) | ≥3.65 | ≥3.75 | ≥3.85 | |
| Tilt Casting QX (RO) | ≥3.65 | ≥3.75 | ≥3.90 | |
| No Shrinkage Casting WS (RT / VF / EPIC / FVP / DCL) | ≥3.75 | ≥3.80 | ≥3.95 |
Fused AZS bricks (Alumina-Zirconia-Silica bricks) are premium refractory materials specifically engineered for glass melting furnaces and other high-temperature glass-contact applications. Due to their exceptional resistance to molten glass corrosion, thermal stability, and long service life, fused cast AZS bricks are widely recognized as the most reliable lining material for critical zones in modern glass furnaces.
At Highland Refractory, we manufacture a full range of AZS33, AZS36, and AZS41 fused cast bricks, supplying customized solutions for float glass furnaces, container glass furnaces, fiberglass production, and specialty glass applications worldwide.
Fused AZS bricks are produced through a high-temperature fusion casting process, where precisely controlled proportions of Al₂O₃ (alumina), ZrO₂ (zirconia), and SiO₂ (silica) are melted and cast into dense refractory blocks.
Unlike sintered refractory bricks, fused AZS bricks feature:
Extremely low porosity
Dense microstructure
Superior resistance to glass penetration
Stable performance at temperatures up to 1550–1600°C
These characteristics make fused AZS bricks the industry standard refractory for areas exposed to direct contact with molten glass.
Glass furnaces operate in one of the most aggressive industrial environments. Refractory linings must withstand:
Continuous exposure to molten glass
Chemical corrosion from glass compositions
High thermal loads and temperature fluctuations
Long production campaigns without shutdown
Fused AZS bricks effectively address these challenges through the following advantages:
Outstanding glass corrosion resistance due to high zirconia content
Minimal glass infiltration, reducing structural degradation
Excellent thermal shock resistance, ensuring lining stability
Long service life, lowering maintenance and replacement costs
For these reasons, fused AZS bricks are indispensable in critical furnace zones where failure would result in costly downtime.
The performance of fused AZS bricks is directly linked to their carefully balanced chemical composition:
Al₂O₃ (Alumina): Provides high refractoriness and mechanical strength
ZrO₂ (Zirconia): Enhances resistance to molten glass corrosion
SiO₂ (Silica): Acts as a stabilizing phase in the glassy matrix
The fusion casting process creates a uniform, interlocked crystal structure that significantly limits glass penetration and crack propagation, even under prolonged high-temperature service.
Selecting the correct AZS grade is critical to achieving optimal furnace performance and cost efficiency.
| Grade | Al₂O₃ (%) | ZrO₂ (%) | SiO₂ (%) | Typical Applications | Key Advantage |
| AZS33 | 54–57 | ≥33 | 10–13 | Upper furnace zones, less aggressive glass contact | Cost-effective, good thermal stability |
| AZS36 | 51–54 | ≥36 | 10–13 | Forehearths, sidewalls, moderate corrosion zones | Balanced corrosion resistance |
| AZS41 | 46–49 | ≥41 | 10–13 | Tank bottoms, throats, high-flow glass areas | Maximum glass corrosion resistance |
AZS33 is suitable for zones with moderate chemical attack and lower glass flow velocity.
AZS36 is the most commonly used grade for forehearths and general glass-contact areas.
AZS41 is recommended for the most severe environments, where long campaign life is critical.
Choosing a higher-grade AZS brick in aggressive zones often results in lower total lifecycle cost, even if the initial investment is higher.
Tank bottoms are continuously exposed to molten glass under static pressure. AZS41 fused bricks are preferred due to their superior resistance to glass corrosion and infiltration, significantly extending furnace campaign life.
Sidewalls experience both thermal stress and chemical attack. AZS36 bricks provide an excellent balance between durability and cost for these zones.
Forehearths require stable thermal performance and resistance to flowing molten glass. AZS36 fused AZS bricks are widely used to maintain smooth glass flow and temperature control.
These are among the most aggressive furnace zones. AZS41 bricks ensure maximum protection, preventing premature wear and glass contamination.
A float glass manufacturer replaced traditional sintered refractory bricks with AZS41 fused bricks in the tank bottom area.
Results:
Furnace campaign life extended by over 24 months
Reduced corrosion-related shutdowns
Improved glass quality consistency
Using AZS36 bricks in the forehearth channel resulted in:
Reduced maintenance frequency
Improved resistance to thermal cycling
Stable operation during long production runs
These real-world applications demonstrate how proper AZS brick selection directly impacts operational efficiency and production stability.
Proper installation is essential to maximize the performance of fused AZS bricks.
Inspect bricks for surface damage
Ensure dry storage conditions
Verify dimensional accuracy
Maintain tight joint tolerances
Use compatible refractory mortars
Avoid excessive mechanical stress during placement
Apply controlled heating rates
Avoid rapid temperature increases
Allow sufficient time for thermal stabilization
Correct installation minimizes thermal shock risk and ensures long-term lining stability.
| Problem | Root Cause | Recommended Solution |
| Early corrosion | Incorrect AZS grade | Upgrade to AZS36 or AZS41 |
| Cracking during startup | Rapid heating | Controlled heating schedule |
| Glass infiltration | High porosity materials | Use fused cast AZS bricks |
| Short campaign life | Improper zone selection | Optimize brick layout by furnace zone |
How long do fused AZS bricks last in glass furnaces?
Typically 18 months to over 3 years, depending on grade selection and operating conditions.
Can fused AZS bricks reduce glass contamination?
Yes. Their dense structure minimizes glass penetration, helping maintain glass purity.
Are custom sizes available?
Yes. Highland Refractory offers custom-shaped AZS bricks based on furnace drawings.
Is AZS brick suitable for non-glass applications?
AZS bricks are ideal for glass-contact environments but may also be used in acidic or neutral high-temperature applications.
Full range of AZS33 / AZS36 / AZS41
ISO-certified manufacturing
Stable quality control and batch consistency
Customized solutions for glass furnace linings
Technical support from experienced refractory engineers
Competitive pricing with global delivery
Selecting the right fused AZS brick can significantly improve furnace performance and reduce long-term costs.
Contact Highland Refractory today for:
Free AZS brick selection consultation
Furnace lining optimization suggestions
Technical data sheets and quotations
👉 Contact our refractory experts now
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