SUPERGARD OBL

From the steel

1. Chemical elements
   Fe, Mn, Si, Al, Ti, Cr…
2. Native inclusions
   Contact with the boundary layer depends on number of casting flow
3. Inclusions formed by cooling
   Formed at the refractory surface
4. Inclusions from reoxidation
   On the refractory surface
5. The healing
   The deoxidizer is trying to take over the slag

From the refactory

1. Permeability (Porosity)
   Path for gases  H₂O, O₂, Air, SiO, CO, N₂
2. Degassing
   Result of refractory composition
   C + SiO₂  → SiO + CO
   C + MgO → Mg + CO
3. Active components
   Silica
   Protective metals Al, Al-Mg
4. Part of everyday process: Gaskets/mortar joint
   Large path for air
   Site of intense reoxidation
   Often result in a breakout

Map of inclusions and impurities in molten steel.

Calcia - CaO

• Very stable oxide

• Violently hygroscopic 

• Reactive with Al2O3 and can form low melting calcium aluminate compounds

• Not a good candidate for most steel making operations

Silica – SiO2

• Low melting point

• Very susceptible to softening at steel temperatures when steel impurities are present

• Can react with metallurgical components in the steel (Al, Ti, Mn) leading to re-oxidation

• Mainly used as backing material behind tundish boards and as a base for older generation pre-shaped boards

Magnesia - MgO

• Stable Oxide

• Melting point of pure MgO is very high allowing a high tolerance for residual compounds (impurities)

• Allows working linings to be made with lower purity.

• MgO compounds, such at Olivine, can lead to the formation of spinel

• Spinel is the “glue” that allows inclusions to increase in size which can lead to SEN clogging and surface defects

• Currently the most popular material of choice for use in Tundish working linings

Alumina – Al2O3

• Chemically pure

• High density and low porosity

• Low reactivity with residual components in steel metallurgy

• Significant reduction in oxygen potential of the Tundish lining system

• Removal of MgO prevents Spinel formation.

• Spinel is the “glue” that allows inclusions to increase in size which can lead to SEN clogging and surface defects.

• Optimized inclusion reduction - Next generation Tundish Working Lining  SUPERGARD

Ingot Casting

→ Evolution →

Continuous Casting

Product types

Bricked Tundish Lining

Pre-shaped Tundish Boards

Trowelable Tundish Lining

Gunnable Tundish Lining

Dry Vibratable Tundish Lining

Sprayable Tundish Lining

Product types have evolved from bricks to spray and dry-vibratable

Materials

Calcia - CaO

Silica – SiO2

Magnesia - MgO

Alumina – Al2O3

Tundish Lining Material technology has evolved from zirconia to alumina

Installation steps:

01.
Apply the first layer
of standard working lining (BASILITE*) 

02.
Apply a 15-20 mm thick layer of SUPERGARD OBL via the same  spray machine over BASILITE spray

03.
Single dry-out cycle
is required.

SUPERGARD OBL installation

Tundish after completion of spray and before dry-out

Tundish after dry-out

Initial success with SUPERGARD OBL application Significant reduction in rejected coils 

6 month utilization of SUPERGARD OBL on entire tundish 

• Over 50% improvement on Lamination/Sliver retreats.

• Over 25% improvement on Lamination/Sliver losses

• 50% reduction in the need for rodding from above the tundish (removing the alumina bridging from wells)

SUPERGARD OBL is an extremely high purity lining barrier for the reduction of re-oxidation in the tundish and SEN clogging with a distinctive impact in steel casting and slab quality.

SUPERGARD readily installed

SUPERGARD OBL
Tundish Working Lining for High Quality Steel