Pyrometric Cone Equivalent (PCE): in refractory testing, PCE is used as an index of which fundamental property of the refractory material?

Introduction / Context:
Pyrometric Cone Equivalent (PCE) is a standardized comparative test used to rate refractories by observing the deformation of test cones under heat in the absence of significant external load. PCE numbers correlate with the softening or fusion behavior, enabling engineers to compare materials quickly for service temperature suitability.

Given Data / Assumptions:

• PCE reflects softening without applied mechanical load.
• Higher PCE indicates resistance to deformation at higher temperatures.
• RUL (refractoriness under load) is related but distinct, accounting for applied load.

Concept / Approach:
PCE is essentially a measure of the temperature at which a refractory cone bends to a specified extent under its own weight as temperature rises. It is, therefore, an index of the material’s fusion or softening point under near-zero load. While corrosion resistance, spalling resistance, and gas attack depend on chemistry and microstructure, PCE specifically captures thermal softening behavior.

Step-by-Step Solution:
Identify the test: PCE measures deformation of cones on heating.Interpretation: correlates to softening/fusion temperature without external load.Match to options: “Fusion point (softening behavior without load)” is correct.

Verification / Alternative check:
Handbooks explicitly state that PCE is a softening index and that RUL is typically lower because service load accelerates deformation at a lower temperature than the PCE alone would suggest.

Why Other Options Are Wrong:
Spalling resistance: assessed by thermal-shock tests, not PCE.Slag penetration or CO attack: corrosion/chemical properties, not captured by PCE.Thermal conductivity: a transport property unrelated to cone deformation.

Common Pitfalls:
Interchanging PCE with RUL; they measure different aspects of high-temperature behavior.Reading PCE as an absolute maximum service temperature; design safety margins are required.

Final Answer:
Fusion point (softening behavior without load)