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How to Select the Right Tundish Burner Block Refractory

2026-03-12

1. Core Functions of Tundish Burner Block Refractory
The tundish burner block serves as the "first line of defense" for the burner, with three non-negotiable roles:

Function	Description	Impact
Thermal Insulation	Isolates 1600–1800℃ flame from the tundish steel shell (safe temp ≤150℃).	Prevents shell overheating, deformation, and red-kiln risks.
Flame Guidance	Shapes flame path for uniform heat distribution, maximizing heat recovery.	Reduces local overheating and molten steel temperature fluctuations.
Erosion & Thermal Shock Resistance	Withstands flue gas erosion, steel splash impact, and rapid temperature cycles.	Extends service life; avoids cracking, spalling, and leakage.

2. Key Selection Criteria: 5 Must-Check Factors
Selection is not one-size-fits-all. Prioritize these 5 factors to match your specific tundish design, burner type, and steel grade.
2.1 Operating Temperature & Thermal Load
Temperature Matching: Refractoriness must be 100–200℃ higher than the maximum operating temp (e.g., ≥1770℃ for regenerative burners, ≥1700℃ for direct-fired burners).
Thermal Load: For 8–12 hour continuous cycles, select materials with hot compressive strength ≥35MPa at 1400℃ to maintain structural integrity.
Warning: Using under-specified materials leads to rapid softening and failure.
2.2 Chemical Erosion Resistance
Follow the acid-base matching principle to avoid chemical reactions:
Alkaline Environments (high CaO/MgO): Choose magnesia-alumina spinel or magnesia bricks for superior resistance.
Neutral/Mixed Environments: Opt for corundum-mullite or high-alumina bricks (Al₂O₃ 60–90%).
Low Porosity: Target ≤18% porosity to reduce corrosive media penetration.
2.3 Thermal Shock Resistance
The #1 cause of failure is rapid temperature changes (20℃ → 1600℃ in 1–2 hours). Evaluate:
Water-Cooled Cycles: Minimum 20 cycles (1100℃) for reliable performance; aim for ≥25 cycles for high-cycle applications.
Thermal Expansion: Choose materials with coefficient ≤5.5×10⁻⁶/℃ (e.g., corundum-mullite) to minimize cracking.
2.4 Mechanical Strength & Wear Resistance
Cold Crushing Strength: ≥40MPa (transport/installation).
Wear Resistance: Abrasion index ≤1.5cm³/1000g (critical for high-velocity flue gas zones).
Fit & Clearance: Ensure precise dimensions to avoid gaps (≤3mm joint width) that cause flame leakage.

2.5 Compatibility & Long-Term Value
Burner Type:
Regenerative Burners: Prioritize high heat retention (low thermal conductivity) + thermal shock resistance (e.g., SiMo bricks).
Direct-Fired Burners: Balance cost and performance (e.g., high-alumina bricks).
Total Cost of Ownership (TCO): Avoid cheap, low-quality blocks that need replacement every 1–2 months. A 20–30% higher upfront cost for premium materials can reduce TCO by 40% over time.
3. Material Comparison: Top 5 Options for 2026

Material Type	Key Properties	Ideal Application	Pros	Cons
High-Alumina Bricks (Al₂O₃ 60–80%)	Refractoriness 1750–1850℃; thermal shock cycles ≥15 次	Direct-fired burners (≤1700℃); medium-scale plants	Cost-effective, easy to install	Limited thermal shock for high cycles
Corundum-Mullite Bricks (Al₂O₃ 80–90%)	Refractoriness 1850–1950℃; thermal shock cycles ≥25 次	Regenerative burners; large plants, high-purity steel	Long life (4–6 months), energy-efficient	Higher upfront cost
Magnesia-Alumina Spinel	Refractoriness 1900–2000℃; excellent alkaline resistance	Regenerative burners; large plants, high-purity steel	Eco-friendly (no Cr⁶⁺), durable	Poor acid resistance, higher cost
SiMo Bricks	Low thermal conductivity (0.8–1.2W/m·K); wear-resistant	Low/medium temp burners (≤1650℃); heat recovery systems	Saves 8% fuel, extends life by 3 months	Not for >1700℃ zones
Clay Bricks	Low cost, excellent thermal shock	Insulation layers, low-temp zones	Cheap, easy to process	Low refractoriness, poor erosion resistance

4. Step-by-Step Selection Process
Step 1: Audit Your Tundish’s 工况 (Operating Conditions)
Document zone temperatures, steel grade (cleanliness requirements), burner type, and cycle frequency.
Identify pain points: frequent spalling, red shell, or short service life (<3 months).
Step 2: Define Zone-Specific Requirements
Firing Zone: ≥1700℃ refractoriness, strong alkaline resistance, high hot strength.
Preheating Zone: Excellent thermal shock resistance, cost-effective.
Cooling Zone: Wear resistance, thermal stability.
Step 3: Match to Materials & Suppliers
Align requirements with the material table above. Avoid over-specifying (wastes cost) or under-specifying (risks failure).
Verify suppliers with: ISO certifications, third-party test reports, and case studies in your steel grade/ tundish size.
Step 4: Validate Installation & Maintenance
Ensure the block fits the burner nozzle and tundish structure (customize if needed).
Confirm the supplier provides installation guidelines and after-sales support.