Fused Cast AZS Brick
Fused Cast AZS Brick
Fused Cast AZS Brick
Fused Cast AZS Brick
Fused Cast AZS Brick
Fused Cast AZS Brick

Fused Cast AZS Brick

Fused cast AZS bricks are the standard glass-contact refractory for the melting tank. The material is melted in an electric arc furnace at around 2000°C and poured into moulds, so the finished block is a dense, interlocked corundum-zirconia structure with a cold crushing strength of 300 MPa or...

Al2O3:45-51%
ZrO2:32-40%
SiO2:12-15%
Type:AZS-33/AZS-36/AZS-41
Fused Cast AZS Brick

Fused Cast AZS Brick Overview

Fused cast AZS bricks are the standard glass-contact refractory for the melting tank. The material is melted in an electric arc furnace at around 2000°C and poured into moulds, so the finished block is a dense, interlocked corundum-zirconia structure with a cold crushing strength of 300 MPa or more. XZK supplies three grades — 33#, 36# and 41# — which differ in zirconia content, density and the behaviour of the glassy phase.

The three grades are not quality levels of the same product; they are engineered for different positions and different dominant wear mechanisms in the tank, and the number in each name states the nominal zirconia content.

What Is a Fused Cast AZS Brick?

The melt-and-cast route is what gives fused AZS its properties. Alumina and zirconia crystallise together as the block cools, forming an interlocked structure with a dense-part bulk density from 3.75 to 3.95 g/cm3 and a cold crushing strength of at least 300 MPa. What remains between the crystals is a small proportion of glassy phase, measured as glass phase exudation at 1500°C for 16 h and held between 2.0% and 3.0%. Casting method controls how that phase and any shrinkage cavity are distributed: the data table therefore lists density separately for the PT/QX, MS/ZWS and WS casting categories, because the same chemistry poured by different methods gives different soundness at the working face.

The grade number states the zirconia content. XZK-FAZS33 carries at least 32.5% ZrO2, FAZS36 at least 36% and FAZS41 at least 41%. Zirconia is the phase that resists dissolution by the glass melt, so corrosion resistance rises with the number, and so does dense-part bulk density, from 3.75 to 3.95 g/cm3. At the same time the silica content falls from 14.0% to 13.0% and the soda content from 1.5% to 1.3%, both of which reduce the proportion of glassy phase and its tendency to exude.

Grade selection follows the mechanism that destroys the block at a given position. FAZS33 has the highest silica and the largest glassy fraction, which gives it the best tolerance of thermal shock; it suits blocks that see repeated heating and cooling and reversal cycling. FAZS41 is the most corrosion resistant and among the least exudable, and is used where melt flow and chemical attack are most severe. FAZS36 sits between the two and is the general-purpose grade for sidewalls, paving and superstructure. Refractoriness under load is at least 1700°C (T0.5) in all three grades, so the choice is never about heat resistance — only about which attack the block will face.

Key Properties

  • Three zirconia grades — 33#, 36# and 41# with minimum ZrO2 of 32.5%, 36.0% and 41.0% respectively, so corrosion resistance can be matched to the position.
  • Bulk density from 3.75 to 3.95 g/cm3 in the dense part, rising with zirconia content and reported separately for the PT/QX, MS/ZWS and WS casting categories.
  • Cold crushing strength ≥ 300 MPa in all three grades, giving the structural capacity required for sidewall, paving and throat blocks.
  • Refractoriness under load ≥ 1700°C (T0.5) across the range, well above the service temperature of any glass contact position.
  • Controlled glass phase exudation of 2.0–3.0% at 1500°C for 16 h, limiting the exudation that causes stone, cord and blowhole defects in the glass.
  • Declining soda content from 1.5% in 33# to 1.3% in 41#, reducing the glassy phase that carries sodium into the melt.

Technical Specifications

Technical Properties XZK-FAZS33 XZK-FAZS36 XZK-FAZS41
Al₂O₃ (%) ≥ 50.0 ≥ 48.0 ≥ 45.0
ZrO₂ (%) ≥ 32.5 ≥ 36.0 ≥ 41.0
SiO₂ (%) ≤ 14.0 ≤ 14 ≤ 13.0
Na₂O (%) ≤ 1.5 ≤ 1.4 ≤ 1.3
Bulk Density (g/cm³) ≥3.75 ≥3.80 ≥3.95
Bulk Density (PT/QX, g/cm²) 3.4 / /
Bulk Density  (MS/ZWS, g/cm²) 3.6 3.7 3.85
Bulk Density (WS, g/cm²) 3.7 3.75 3.9
Cold Crushing Strength (MPa) ≥300 ≥300 ≥300
Refractoriness Under Load T0.5 (℃) ≥1700 ≥1700 ≥1700
Glass Phase Exudation (%) 1500℃×16h ≤ 2.0 ≤3.0 ≤2.5

Test methods follow GB/T and ISO practice; ASTM equivalents and full certificates of analysis are issued with every shipment.

Available Grades and How to Choose

Zirconia content is the single variable that governs service life at a given position, so grade selection is normally read directly from a zoning drawing rather than chosen per furnace.

  • XZK-FAZS33 (ZrO2 ≥ 32.5%, Al2O3 ≥ 50.0%, SiO2 ≤ 14.0%, Na2O ≤ 1.5%). The thermal-shock-tolerant grade, with the highest silica and glassy fraction and the lowest density. Used in upper sidewall, superstructure and port positions where reversal cycling is the dominant wear mechanism.
  • XZK-FAZS36 (ZrO2 ≥ 36.0%, Al2O3 ≥ 48.0%, SiO2 ≤ 14%, Na2O ≤ 1.4%). The balanced general-purpose grade, dense-part bulk density 3.80 g/cm3. Used for sidewall courses below the flux line, tank bottom paving, throat construction and the port neck.
  • XZK-FAZS41 (ZrO2 ≥ 41.0%, Al2O3 ≥ 45.0%, SiO2 ≤ 13.0%, Na2O ≤ 1.3%). The most corrosion-resistant grade, dense-part bulk density 3.95 g/cm3 and the lowest soda content. Reserved for the flux line, the throat and any block where melt contact severity decides campaign length.

Industry Applications

  1. ‌Glass Industry (Primary Application):‌ The dominant use, essential for glass melting furnaces.

    • ‌Tank Walls:‌ Lining directly contacting molten glass, resisting erosion (using AZS 33#, 36#).
    • ‌Throat:‌ Highest erosion zone (high glass flow, temperature, scour); requires high-zirconia AZS (e.g., AZS 41#).
    • ‌Weir/Dam:‌ Separates melting/refining zones, withstands heavy erosion/scour.
    • ‌Bubbler Blocks:‌ Houses bubbling systems, resistant to molten glass and gas scour.
    • ‌Doghouse (Charging End):‌ Withstands batch material impact and thermal cycling.
    • ‌Forehearth:‌ Channels molten glass to forming equipment; contact surfaces often use AZS.
    • ‌Blowing Cylinders (Tube Glass):‌ Direct contact with molten glass.
  2. ‌Non-Ferrous Metallurgy:‌

    • ‌Aluminum Smelting:‌ Lining for electrolytic cells (sidewalls, cathode blocks), resisting molten cryolite and aluminum.
    • ‌Copper Smelting:‌ Lining slag lines and erosion-prone areas in anode/refining furnaces (molten copper, matte, slag).
  3. ‌Iron and Steel Industry (Specific Applications):‌

    • ‌Ladle Furnaces:‌ Slag line areas, especially with highly basic slags or special steels.
    • ‌AOD/VOD Converters:‌ Critical zones (tuyere areas, slag lines) in stainless steel refining.
    • ‌Reheating/Soaking Furnaces:‌ Skid rails in high-temperature sections.
  4. ‌Waste Incineration & Melting:‌

    • ‌Slag Melting Furnaces:‌ Lining (especially melt bath) resisting highly corrosive molten slag from municipal/industrial waste.
  5. ‌Chemical & Ceramic Industries:‌

    • ‌High-Temperature Reactors/Furnaces:‌ Lining for equipment handling corrosive molten salts, chemicals, or special ceramic glazes.

Where Fused Cast AZS Bricks Are Used in a Glass Furnace

Fused cast AZS occupies the melt-contact positions of the tank, where the combination of high temperature, melt flow and chemical attack is most severe. Grade choice changes with the position rather than with the furnace.

  • Flux line and melting tank sidewall. The flux line is the hardest duty in the furnace: intense chemical corrosion from the melting glass plus continuous mechanical scour from the surface circulation. FAZS41 is specified for the flux-line courses of high-pull furnaces, with FAZS36 below the flux line where attack moderates with depth.
  • Throat. The throat runs the highest melt velocity in the tank together with frequent thermal shock. Dense-cast and void-free blocks in the 36# or 41# grade are used for throat walls and throat covers, where the soundness of the casting matters as much as the chemistry.
  • Tank bottom paving. Paving is exposed to upward drilling by heavy metal contaminants that settle out of the batch. Fused cast AZS is laid above a zircon barrier, and the lowest-porosity casting categories are used where the paving meets the sidewall.
  • Superstructure and breastwall. Blocks above the melt, including breastwall courses and the lower superstructure, face alkali vapour and flame radiation without direct melt contact. Grade 33# is often used here because its better thermal shock tolerance suits the cycling of the upper structure.
  • Burner port neck and port floor. The port region is cycled between flame and cold secondary air, and the block must resist flame scour at temperature; 33# and 36# blocks are used according to the local heat flux.
  • Doghouse and charging end. Charging subjects the blocks to splash, batch dust abrasion and thermal cycling, and fused cast AZS forms the melt-contact face behind the doghouse structure.

Manufacturing and Quality Control

Manufacturing is controlled from raw material through to finished brick. Four automatic batching lines feed 20 CNC presses ranging from 630 to 2000 tonnes, so density is set by press force rather than operator judgement, and firing runs through four 108-metre fully automatic tunnel kilns and five ultra-high-temperature shuttle kilns for a uniform soak.

Every batch is tested for bulk density, apparent porosity, cold crushing strength and refractoriness under load, and ships with a certificate of analysis. XZK Group holds ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certification and operates the Henan Provincial Engineering Technology Research Center for Sintered Refractories for Glass Furnaces.

Related Refractory Products

Fused cast AZS is the melt-contact layer of a complete melting basin system, working with sintered AZS bricks in the doghouse and superstructure, zircon bricks and zircon ramming mass in the sub-layer and bottom, AZS ramming mass at the paving joints and high-alumina insulating bricks beneath the tank. See the AZS bricks range for zoning guidance or browse all refractory products.

Proven Global Projects

Wuliangye Group
Location China
Year 2015.04
Furnace Type Glass Kiln
Supplied Material Zircon Bricks
Wujiang CSG Glass Co., Ltd.
Location China
Year 2022.12
Furnace Type Glass Kiln
Supplied Material Sillimanite Bricks
Zhangzhou Kibing Glass Co., Ltd.
Location China
Year 2015.03
Furnace Type Glass Kiln
Supplied Material Sillimanite bricks

About XZK Group

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Specializing in premium zircon, corundum, sintered AZS, and monolithics. With a $70M+ annual output, we deliver durable linings for global high-temp industries.
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✔ 4 automated microcomputer batching systems.
✔ 4 ultra-high-temp tunnel kilns & 5 shuttle kilns.
✔ 20+ CNC hydraulic presses (630-1500T).
✔ Digitalized workshops with 100,000T annual capacity.
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93 patents, featuring the "Tri-Resist Brick" for glass kilns. Field-proven for superior corrosion and thermal shock resistance.
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Co-authored multiple National Standards for Andalusite, Chrome-Corundum, and Zircon bricks with CBMA.
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Led by Prof. Shi Gan, our 40+ engineers leverage advanced testing centers to drive innovation in green refractory technologies.
Professor Shi Gan
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Key drafter of 5+ national refractory standards.
Inventor of "Tri-Resist Brick", maximizing glass furnace lifespan.
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Zhongke Refractories
Insulating Materials Base: Alumina Bubble, Mullite, High-Alumina & Fireclay bricks.
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Premium Refractories Base: Zircon, Corundum, Sintered AZS, and monolithics.
Zhengzhou Zhongke Refractories Co., Ltd. Zhengzhou Zhongke New Materials Co., Ltd. Zhengzhou Henruida New Materials Co., Ltd.
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Certified by ISO 9001, 14001, 45001, 50001 Management Systems.

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