Difficulty: Easy
Correct Answer: Softening temperature
Explanation:
Introduction / Context:
Seger cones (also spelled Segar) are standardized pyrometric devices that bend at calibrated temperatures during kiln firing. They offer a simple, practical way to judge the heatwork a refractory body has experienced and to estimate softening behavior without complex instrumentation.
Given Data / Assumptions:
Concept / Approach:
When a Seger cone reaches its rated heatwork, it bends or “matures,” signaling that the specimen has attained a softening stage corresponding to the cone number. In refractory practice, this is linked to softening temperature or PCE (pyrometric cone equivalent). While many modern labs use RUL and other tests, cones remain a quick, visual indicator for softening ranges and kiln control, especially in ceramics and traditional refractory shops.
Step-by-Step Solution:
Place cones near the specimen during firing.Observe the cone’s bending at the designated heatwork.Translate the cone number to an equivalent softening temperature range.
Verification / Alternative check:
Standards map cone numbers to equivalent temperatures; comparing cone deformation with thermocouple readings confirms the correlation to softening behavior.
Why Other Options Are Wrong:
Spalling resistance: requires thermal-shock cycling tests, not cones.Electrical conductivity: measured with electrical methods, not heatwork cones.Resistance to slag attack: assessed via corrosion/immersion or cup tests.Apparent porosity: measured by boiling water vacuum or similar methods.
Common Pitfalls:
Treating cone temperature as an exact fixed point; cones indicate heatwork (temperature plus time).Using cones as a substitute for RUL/PCE standards in specification-critical testing.
Final Answer:
Softening temperature
Discussion & Comments