Application mapping: alumina–graphite bricks are typically used for which steel plant components due to their thermal shock resistance and non-wettability by molten steel?

Introduction / Context:
Composite refractories combining alumina with flake graphite are engineered for contact with molten steel. Graphite imparts non-wettability and thermal shock resistance, while alumina provides refractoriness and strength. Knowing where these bricks are deployed is essential for casting and ladle-handling operations.

Given Data / Assumptions:

• High thermal gradients and steel/slag contact occur in slide gates and tundish/continuous casting paths.
• Materials must resist erosion, thermal cycling, and metal penetration.
• We map common components to material properties.

Concept / Approach:
Alumina–graphite bricks exhibit low wettability to molten steel, good thermal shock resistance, and acceptable corrosion resistance when designed properly. These traits are ideal for slide gate plates/nozzles in teeming ladles and for tundish/continuous casting zones exposed to steel flow and intermittent heating. They are less suited to checker bricks in blast furnace stoves, which face different service conditions focused on regenerative heat exchange rather than direct steel contact.

Step-by-Step Solution:
Identify required properties: thermal shock resistance, non-wettability, erosion resistance.Match to components: slide gates and tundish/CC hardware demand exactly these.Exclude stove checkers: different duty profile and material optimization.Select “Both (a) and (b).”

Verification / Alternative check:
Supplier catalogs and plant standards list alumina–graphite for slide gate plates, nozzles, and tundish impact/working linings, corroborating this mapping.

Why Other Options Are Wrong:
Only (a) or only (b): too narrow; both are standard uses.Neither/Only stove checkers: do not reflect common steelmaking practice.

Common Pitfalls:
Assuming high-alumina alone suffices; graphite additions are key to shock resistance and non-wettability in these dynamic casting interfaces.

Final Answer:
Both (a) and (b)