Pusher-type reheating furnaces in steel mills: These continuous furnaces are typically used for bringing which product to rolling temperature before the mill?

Introduction / Context:
Reheating furnaces raise semi-finished steel products to a uniform temperature suitable for hot rolling. Pusher-type furnaces advance the stock on skid rails or hearths by periodically pushing the charge forward through preheat, heating, and soaking zones.

Given Data / Assumptions:

• Continuous, longitudinal furnace with zones and flue gas flow.
• Material advanced by mechanical pusher.
• Common steel mill practice.

Concept / Approach:
While walking-beam and walking-hearth designs are widely used today, classic pusher furnaces have long handled slabs and billets. Among the listed forms, slabs are the archetypal feed to pusher furnaces prior to hot strip or plate mills. Coils and sheets are usually heated in batch or bell furnaces; ingots historically used soaking pits or different furnace arrangements.

Step-by-Step Solution:

Verification / Alternative check:
Process flowsheets show slab casters feeding slab yards, then pusher or walking-beam reheating into hot strip mills.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming any steel form can be reheated in any furnace; geometry and handling dictate furnace choice.

Final Answer:
slabs