Refractory testing — The “panel test” for refractories primarily determines which performance property?

Introduction:
Refractory selection depends not only on composition and refractoriness but also on resistance to thermal shock and spalling. The panel test is one of the standardized ways to evaluate how a refractory endures rapid heating and cooling cycles that cause surface layers to flake off.

Given Data / Assumptions:

• Test type: panel test.
• Objective: determine resistance to damage from thermal shock and cyclic temperature changes.
• Other properties like RUL and fusion point are measured by different tests.

Concept / Approach:
Spalling resistance reflects a material’s ability to withstand abrupt temperature gradients without cracking or delaminating. Panel tests expose a refractory panel to cycles of heating/cooling to simulate service conditions, and the degree of surface damage or cracking is assessed.

Step-by-Step Solution:
Identify what panel test stresses: thermal cycling → spalling behavior.Map other properties to tests: fusion point by pyrometric cones; RUL by load-bearing under temperature; slag penetration by crucible/slag tests.Thus, panel test aligns with spalling resistance.

Verification / Alternative check:
Standards and refractory testing manuals explicitly classify panel/thermal shock tests under spalling resistance evaluations.

Why Other Options Are Wrong:

• Fusion point: measured via cone fusion or high-temperature microscopy.
• Slag penetration: assessed by slag cup/immersion tests.
• RUL: determined under load at temperature in a dedicated apparatus.

Common Pitfalls:
Confusing general “high-temperature tests” with specific performance evaluations; assuming one test covers multiple properties.

Final Answer:
Spalling resistance