Precast Solutions


Traditionally, reheat furnace linings are built with layers composed of a plastic material, or a castable in the hot face, a different composite behind, and ceramic fiber on the back face. The rammed solution is still available, demonstrating very good performance—particularly regarding thermal shock behavior. However, it requires more time for the installation and dry-out than other solutions. It is not only impossible to work on the roof and hearth at the same time, but the shutdown time of the furnace is quite high as well.

With increasing international competition within the steel industry, the demands of reheat furnaces call for reliable equipment with minimum shut-down. An alternative installation method based on precast blocks can increase their efficiency by at least 300% compared to the cast in situ installation. Additionally, this solution has an inherent advantage of superior quality due to better process controls in the manufacturing plant.

The Calderys CALDE™ BLOCK ROOF is designed to decrease energy consumption in the operating furnace and sustain performance during ramming without the disadvantage of a long installation shutdown.

The main advantages of CALDE™ BLOCK ROOF are:

  • Significant time savings versus a cast in situ roof
  • Possibility to include burners easily within the structure
  • Possibility to use the system in an inclined section of the roof
  • In case of anchor breaking or defect climb the precast piece is self blocked and cannot fall down into the furnace


Research for optimizing the efficiency of preheating, and heating, the stock (billet, blooms, slabs…) has driven Calderys to develop a specific design for the hot face of the block, which maximizes the radiation efficiency. The best way to increase the radiation efficiency consists of maximizing the surface of contact. Compared to a flat roof structure, our CALDE™ BLOCK ROOF DIAMOND product gains 9% more surfaces. This solution also allows for quicker preheating and close to 5% savings in energy (mainly in the preheating zone).

Main advantages of the CALDE™ BLOCK ROOF DIAMOND:

  • Quick installation time: a team of 5 workers can install 6 pieces per hour and a full roof can be installed in 5 days (300 pieces per shift with 4 lifting tables).
  • Time savings in installation: no need for a traditional insulating back layer, these are already part of the precast block.
  • Excellent thermal shock resistance for the materials found in the furnace, which are specifically chosen for this application, including the ceramic anchor
  • Top radiation effect minimizing the shadow from one stock to another
  • Return on investment for the customer for a middle furnace only takes 12 months, due to a 2% reduction in energy (depending on the surface)
Block Roof Diamond
Block Roof Diamond
Roof Diamond
Roof Diamond

This concept can be applied not only to continuous furnaces (like pusher, walking beam, or walking hearth furnaces), but also for Rotary hearths. The CALDE™ BLOCK ROOF DIAMOND product meets the strict demands of the reheat furnaces and has quickly become a real success story at Calderys with high profile references in France, India, Korea, and Russia.

You need a dedicated anti-abrasion solution, contact our experts!

(*)To acquire its final properties, regular castables need to be installed by means of adding the appropriate amount of water. Usually, with the heat up, the castables binder transforms and forms a ceramic bond by combination with part of the water. The water has to be evacuated by means of heating up to steam stage. The speed of evacuation depends on the permeability of the castable. That is why the dry-out of the newly installed refractory is critical to achieve the final desired properties of the lining by slowly evaporating the inside existing water out of the lining without damaging it. Calderys developed a new binder that gives more permeability to the gases, allowing early water evaporation at low temperature.

About Calderys

Our mission is to help you meet your ever increasing production and productivity targets, whilst protecting the safety of your people and the integrity of your equipment. Our focus is to deliver safe, reliable and high performing refractory solutions customized to your needs. Our international production and sales facilities allow us to develop and deliver customized solutions based on monolithic and ready shape monolithic refractory materials worldwide in a fast, efficient, and safe manner.


Reheat Furnace Monolithic Solutions

Case studies 01

Our range of innovative monolithic refractory concepts for Reheat Furnaces are providing cost savings to steelmakers due to benefits including higher energy saving and reduced installation time.

Read more

Skids & Posts Precast Solutions

Case studies 01

The CALDE™ range of precast products for skids and posts for reheat furnaces can lead to significant operational savings on installation time and energy.

Read more

Project Management Testimony

Case studies 01

Blending technical knowledge with practical experience, our dedicated project managers provide the organization and coordination needed to support installation and special projects worldwide.

Read more

JOBS / Careers

Related companies:,,,