Reheating furnaces in steel plants: Which design is considered an improved, more fuel-efficient successor to the traditional pusher-type reheating furnace for heating slabs/billets prior to rolling?

Introduction / Context:
Pusher-type reheating furnaces were common in older rolling mills, but modern steel plants favor designs that save fuel, reduce scale losses, and deliver tighter temperature uniformity. This question checks whether you can identify the evolved configuration that improves thermal efficiency and product quality while minimizing mechanical contact damage and skid marks.

Given Data / Assumptions:

• The application is reheating steel slabs/billets/blooms before hot rolling.
• Key goals: better heat transfer, lower fuel consumption, reduced oxidation/scale, and smooth handling.
• “Improved and fuel efficient” refers to mainstream industrial practice, not niche or laboratory furnaces.

Concept / Approach:
A walking beam furnace lifts the workpiece off supports and “walks” it forward, alternating between stationary and advancing beams. By reducing continuous sliding, it cuts skid-mark cold spots, promotes more uniform soaking, and enables optimized combustion/recuperation. Higher heat-transfer effectiveness allows lower specific fuel use for the same throughput and exit temperature targets.

Step-by-Step Solution:
Identify drawbacks of pusher type: sliding abrasion, temperature non-uniformity, scale build-up, potential billet sticking.Match improved design: the walking beam mechanism lifts and conveys without dragging, improving temperature uniformity and surface quality.Link to efficiency: better exposure to hot gases and optimized zone control lower fuel per ton.Therefore, the correct choice is “Walking beam furnace”.

Verification / Alternative check:
Process heat texts and OEM catalogs consistently cite walking beam furnaces as the modern standard for high-productivity, fuel-efficient slab/billet reheating with excellent temperature homogeneity.

Why Other Options Are Wrong:
Shaft furnace: used for other materials and chemistries; not the mainstream reheating replacement.Tunnel kiln furnace: common for ceramics; not the standard for steel reheating lines.Rotary hearth furnace: suited for specific processes (e.g., DRI, forging stock), not the universal pusher successor.Walking hearth furnace: improves handling but the widely adopted efficiency upgrade is the walking beam variant.

Common Pitfalls:
Assuming any non-pusher system is the “upgrade.” The signature energy and quality benefits that displaced pushers in major mills are most closely associated with walking beam designs.

Final Answer:
Walking beam furnace