Soaking furnaces are typical pit-type metallurgical industrial furnaces used in blooming mills for heating and soaking steel ingots. They mainly raise the temperature of steel ingots and equalize their temperature before breakdown rolling. The furnace chamber temperature can typically reach 1350–1400°C, and the furnace operates through intermittent heating, soaking, and ingot discharging cycles. Because different furnace areas are exposed to significantly different thermal loads, mechanical impact, and corrosive conditions, the lining design of a soaking furnace cannot rely on a single material. Instead, materials must be zoned according to the operating characteristics of each structural area.
Hot-Face Areas of Furnace Walls and Hearth: Mainly High-Strength Dense Refractories
The hot-face furnace walls and hearth are the most demanding areas in a soaking furnace. They are exposed for long periods to high-temperature radiation, steel ingot impact, rapid temperature changes, and slag attack. Therefore, the material requirements are not limited to high refractoriness, but also include good mechanical strength, slag resistance, and thermal stability.
In these areas, the working lining should generally give priority to high-strength dense refractories to ensure structural safety and service life during long-term operation. For soaking furnaces, refractory fibers such as ceramic fibre block are generally not suitable as the direct working lining for hot-face furnace walls or load-bearing hearth areas. They are more suitable for protected insulation layers behind the working lining, helping reduce heat loss and improve overall energy efficiency.
Regenerator Chamber: The Core Area Most Suitable for Fiber Insulation Structures
Unlike the hot-face furnace walls and hearth, the main function of the soaking furnace regenerator chamber is to recover residual heat from the furnace. Its maximum temperature is generally around 950–1100°C. This area has relatively low mechanical load, but requires good insulation performance, heat storage control, and long-term sealing integrity. Therefore, it is usually the most suitable area in a soaking furnace for refractory fiber linings.
For the side walls, end walls, and roof of the regenerator chamber, a composite structure using CCEWOOL® 1400LZ ceramic fiber blanket as the veneering layer + CCEWOOL® 1430HZ S-Fold thermal ceramics modules as the module layer is generally more reasonable. The veneering layer mainly provides auxiliary insulation, leveling, and compensation, while the thermal ceramics modules form the main insulation layer, helping reduce heat loss, lower lining weight, improve installation efficiency, and enhance long-term operating stability.
Compared with traditional heavy insulation structures, this composite fiber lining is more conducive to reducing furnace heat storage, improving thermal response speed, and enhancing the overall sealing and energy-saving performance of the regenerator chamber.
Permanent Cold-Face Insulation Layer: An Important Area for Reducing Shell Temperature and Heat Loss
In the overall lining system of a soaking furnace, the permanent cold-face insulation layer is a very important application position for CCEWOOL® ceramic fibre block. This layer does not directly bear steel ingot impact, nor is it directly exposed to slag attack or flame erosion. However, it plays a clear role in controlling furnace shell temperature rise, reducing outward heat transfer, and improving system energy consumption.
In this structural layer, CCEWOOL® 1260HPS ceramic fiber blanket, board, and CCEWOOL® 1260°C ceramic fibre block can be configured according to design requirements. For projects requiring improved energy-saving performance, lightweight fiber insulation layers with low thermal conductivity are usually more effective than traditional heavy insulation layers in reducing heat loss and lowering the overall furnace load.
Especially in energy-saving renovation projects for soaking furnaces, optimizing the permanent cold-face insulation layer is often one of the easiest measures to implement and one of the most direct ways to demonstrate energy-saving results.
Furnace Cover, Charging Opening, and Edge Sealing Areas: More Suitable for Fiber Compensation and Sealing Structures
Although the furnace cover, charging opening, and edge connection areas may not bear heavy steel ingot loads like the hearth, they are often areas where heat leakage is more obvious during operation. These areas repeatedly experience opening and closing movements, local thermal shock, and slight structural displacement. Therefore, the design must consider not only insulation performance, but also sealing effectiveness and compensation capability.
In these areas, CCEWOOL® 1260°C ceramic fiber rope and tape are more suitable for sealing, compensation, and localized lightweight insulation. Compared with rigid materials, ceramic fiber textiles can better adapt to local displacement changes and maintain contact continuity, thereby reducing heat leakage and improving overall thermal integrity. For areas requiring frequent maintenance or local replacement, fiber structures also offer greater flexibility in installation and maintenance.
Localized High-Stress Areas: Stronger Integral Transition Lining Structures
In soaking furnaces, areas around burners, flue gas turning sections, openings, and local structural connections are usually zones where thermal load and stress are more concentrated. These areas are exposed not only to high temperature, but also potentially to gas flow erosion, local structural restraint, and thermal stress concentration.
For these positions, it is usually more suitable to use products with stronger integrity, such as CCEWOOL® ceramic fiber shapes, or fiber castable structures to form smooth transitions with surrounding fiber layers. This helps reduce local thermal bridges, lower cracking risk, and improve the overall stability of lining nodes. Although these areas are not large, they have a clear impact on the overall lining life and operating reliability of the soaking furnace, so they must be considered separately in the design.
The Key to Soaking Furnace Lining Optimization: Not Full-Furnace Fiberization, but Reasonable Zoned Configuration
A soaking furnace is different from a general continuous heating furnace. During operation, it faces multiple working conditions, including high temperature, impact, thermal shock, and intermittent temperature variation. Therefore, the key to lining optimization is not full-furnace fiberization, but reasonable material allocation based on the operating characteristics of different areas.
A more reasonable configuration usually includes:
Hot-face furnace walls and load-bearing hearth areas: high-strength dense refractories to ensure structural safety and durability
Regenerator chamber side walls, end walls, and roof: a composite structure of CCEWOOL® 1400LZ ceramic fiber blanket as the veneering layer + CCEWOOL® 1430HZ S-Fold thermal ceramics modules
Permanent cold-face insulation layer: CCEWOOL® 1260HPS ceramic fiber blanket, board, and CCEWOOL® 1260°C ceramic fibre block to reduce furnace shell temperature rise and heat loss
Furnace cover, charging opening, and edge sealing areas: CCEWOOL® 1260°C ceramic fiber rope and tape for sealing and compensation to reduce heat loss and improve stability at opening and closing areas
Localized high-stress nodes: CCEWOOL® ceramic fiber shapes or other stronger integral transition lining structures to improve local reliability
This zoned design approach allows different materials to fully perform their respective advantages, helping the soaking furnace achieve a more reasonable balance among energy saving, structural stability, installation efficiency, and maintenance convenience.
For metallurgical industrial furnaces such as soaking furnaces, which operate under high temperature, intermittent temperature variation, and relatively heavy mechanical loads, the core of lining design is not simply pursuing a higher temperature rating, nor simply promoting full-furnace fiberization. Instead, it is about building a more scientific product configuration logic around the actual working conditions of different structural areas.
In high-load hot-face areas, high-strength dense refractories should be maintained. In the regenerator chamber, permanent cold-face insulation layer, and local sealing and compensation areas, the lightweight and efficient insulation advantages of CCEWOOL® ceramic fibre block should be fully utilized. Only a systematic design based on structural zoning can achieve a more reasonable lining configuration, more stable long-term operating performance, and better energy-saving results.
Post time: Apr-28-2026
