Selection Of Corundum Bricks

1. Identify Core Performance Indicators and Prioritize Key Parameters

The performance of corundum bricks directly determines their service life. The following indicators should be carefully checked and confirmed through product testing reports:

Al₂O₃ Content: This is the core indicator of corundum brick grade. Higher content indicates stronger high-temperature resistance and corrosion resistance. Ordinary corundum bricks have an Al₂O₃ content ≥90%, while high-alumina corundum bricks have ≥95%. So choose the appropriate grade based on the application scenario.

Bulk Density: The higher the value, the denser the brick, and the better its resistance to penetration and erosion. Generally, ≥3.6g/cm³ is required; low-porosity products require ≥3.8g/cm³.

Room Temperature Compressive Strength: Reflects the brick’s impact and compressive strength. Typically, ≥200MPa is required, and ≥250MPa is required for high-intensity applications.

Thermal Shock Stability: In high-temperature and rapid-cooling environments, pay attention to the “number of water cooling cycles” indicator. Generally, ≥15 cycles without cracking is required.

2. Observe Appearance and Structure, Eliminate Obvious Defects

By visual inspection and simple touch, the processing precision and internal quality of corundum bricks can be preliminarily judged:

Surface Condition: No obvious cracks, missing corners, or bubbles; uniform color. Black spots or impurities on the surface may indicate insufficient raw material purity or defects in the sintering process.

Dimensional Tolerance: Measure length, width, and height with a tape measure; the error must conform to industry standards (e.g., ±1mm). Because irregular dimensions will lead to excessively large gaps during construction, and then affecting high-temperature resistance.

Cross-sectional Structure: The fracture surface should be dense, without loose pores, and with uniform particle distribution. Obvious layering or large pores on the cross-section indicate insufficient sintering, affecting strength.

3. Match Specific Needs to the Application Scenarios

Different application scenarios have different requirements for corundum bricks, necessitating targeted selection:

High-Temperature Kilns: Prioritize products with high Al₂O₃ content (≥95%) and high thermal shock stability in order to avoid cracking at high temperatures.

Chemical corrosion protection: Select corundum bricks with low porosity (≤1%) and resistance to acid and alkali corrosion in order to prevent media penetration and erosion of the brick body.

Metallurgical industry: High strength (pressure resistance ≥220MPa) and erosion resistance are required to prevent spalling caused by molten steel erosion.