Tundish Insulation Boards for Continuous Casting

The tundish is the last vessel steel touches before it becomes a strand. It buffers the flow from ladle to mould and keeps the metal at a controlled superheat for the entire casting sequence. If the tundish lining lets heat escape, temperature drifts, and that drift shows up downstream as surface defects, inclusions, and — in the worst case — a breakout. A nano microporous backup layer under the working lining is a direct way to hold that temperature steadier.

The Cost of Tundish Temperature Drift

Continuous casting runs on a narrow superheat window. Too hot and you risk breakouts and centre-line segregation; too cold and the metal starts to skull, clog, or freeze in the nozzles. A tundish that loses heat through its walls forces the shop to tap hotter than necessary, which raises energy use and shortens refractory life. Steadier tundish temperature lets the caster run closer to the ideal superheat with a wider safety margin.

How the Backup Layer Is Installed

Nano microporous boards are laid flat against the tundish shell on the inner wall, then the castable working lining is applied over them. Installation follows the same discipline as a standard tundish reline, with a few points worth noting:

Boards are laid against the clean shell, avoiding box nails and anchor points.
Joints are closed so the layer forms a continuous thermal break.
The castable working lining is then installed over the boards as normal.
Flexible sheet is used on the curved bottom and nose sections where rigid board does not sit flat.

The boards are non-fibrous and cuttable, so they can be trimmed to the tundish profile on site without specialist tooling.

What Changes on the Caster

Reduced heat loss through the tundish walls during the casting sequence.
Steadier metal temperature from start to end of the sequence.
Lower tapping superheat, with the associated energy saving.
Less skull and nozzle clogging, which reduces sequence interruptions.

For shops that already fight temperature drop at sequence changeovers or on the first few metres of each strand, the tundish backup layer is where the improvement shows up fastest.

Board Selection for Tundishes

The backup layer sits behind the castable, so the working temperature it sees is well below the steel temperature. Grade 1000 (1000 °C) is the standard grade for tundish backup; where the design puts the board closer to the hot face, Grade 1100 (1100 °C) is available. Board thickness is typically 3-10 mm and is confirmed by a thermal calculation for the specific tundish geometry.

Property	Value
Grades	Grade 950 (950 °C) / Grade 1000 (1000 °C) / Grade 1100 (1100 °C)
Density	220–280 kg/m³
Thermal conductivity, 400 °C	0.025 W/m·K
Thermal conductivity, 800 °C	0.034 W/m·K
Form	Rigid board, flexible sheet, pre-formed shapes

The same microporous core is available as a flexible sheet with a high-temperature fabric facing, which is useful for the tundish bottom and curved regions where a rigid board would be awkward to fit.

Recommended products for this application: flexible nano microporous sheet for the tundish bottom, steel ladle insulation, and standard boards for the wall sections.

Frequently Asked Questions

Does the board replace the castable working lining?

No. The nano microporous board is a backup insulator installed between the shell and the castable. The castable remains the hot-face wear layer; the board simply slows heat flow through the wall behind it.

How is board thickness decided?

By layer-by-layer thermal calculation. Each layer in the tundish lining is assigned its thermal conductivity and thickness, and the board is sized so the interface temperature it sees stays within its continuous-use rating. This is a standard part of a project-specific design.

Can one board serve multiple tundish relines?

The board is part of the consumable lining and is typically replaced with each reline. Its value is in what it saves over the casting campaign, not in reuse.

Does the board affect tundish preheating?

It can shorten preheat. The microporous layer’s low thermal mass stores less heat than a conventional backing refractory, so the tundish reaches working temperature faster and holds it more steadily when the sequence is interrupted.

Casting quality starts with temperature control. Contact us for a tundish-specific board and thickness recommendation, or review our steel ladle insulation for the upstream vessel. Contact us to get started.