Tundish Nozzles and Gaskets
Tundish Porous Nozzles for Casting Clean Steel
Alumina accumulation in the casting channel has been a limitation in the continuous casting industry for several decades. The problem has a major impact on the steel quality and the economics of the process. Finding a solution has mobilized major efforts everywhere in the industry.
The tundish nozzle is seen as the most critical component of the channel since it cannot be replaced during casting. VESUVIUS is a leader in the development of casting channel refractories, capable of reducing clogging. Beyond our available products, several new designs and materials are in the development stage, creating the future generation of advanced clogging reduction nozzles.
VESUVIUS offers a wide variety of extruded (VAPEX®) or isostatically pressed (VISO™) tundish nozzles for slide gate or stopper rod applications. Our development and engineering work has yielded designs that are unique in the industry. Each nozzle is engineered for particular customer needs, keeping in mind the quest for cleaner steel. The refinement of our porous compositions applied in our cutting edge engineering designs allows our customers to reach over 30 heats or 25 hours of Aluminium killed slab casting. Similar performance is being reached in long product casting.
The Design
VESUVIUS has developed the best nozzles that can be offered to the casting operator. Their performance is due to the careful combination of 5 major components.
- Optimum refractory pore size
- Patented system of argon distribution channels
- Argon containment within the nozzle
- Leak free argon connector options
- Proprietary sealant materials and process
Installation and Operation
Installation in the tundish is one of the most critical steps in the performance of a nozzle. VESUVIUS has developed standard recommendations for the setting of the porous tundish nozzles. Included are guidelines on the correct tools to be used as well as for the ancillary refractories. When needed, we will tailor this recommendation to suit particular needs.
The Porous Refractory
Different steel grades have different interactions with the refractories, which are influenced by the flow control system. To satisfy this wide range of customer needs, we have developed porous materials for even the most demanding operations. We offer a wide range of compositions that include Magnesia, Alumina, Alumina-Carbon and Zirconia.
The Tundish Nozzle and the Subentry Shroud are designed to perform all the functions of a Subentry Nozzle when the application of a one-piece tube is not possible or where more flexibility is necessary in the casting operation.
The Tundish Nozzle, in conjunction with the Stopper, controls and protects the steel stream before it exits the tundish. The full range of VESUVIUS materials are available to provide erosion resistant seat areas and anti-clogging properties in the casting channel.
The connection between the refractory components needs to be tight to ensure that there is no air ingress resulting in steel re-oxidation and nitrogen pick-up with consequent steel downgrading. This phenomenon is emphasized by the Venturi effect due to the steel flow and by the negative pressure inside the refractory components.
VESUVIUS provides a wide range of gasket types to ensure the best possible joint sealing. The gasket materials and dimensions are custom designed to suit customers' operating conditions.
The benefits from incorporating airtight VESUVIUS Gaskets are:
- Reduce nitrogen pick-up.
- Improved steel cleanliness by preventing the formation of inclusions due to re-oxidation.
- Reduced incidences of nozzle blockage due to re-oxidation and alumina formation.
- Reduce damage to collector nozzles.
- Better sealing of re-used ladle shrouds, due to the flexibility of the gasket.
- Easy application and removal after use.
Air Tight Gasket Types
- Ceramic Fibre
- Cut Fibre
- Vacuum Formed
- Impregnated for superior performance
- VG SEALBIND™ ceramic gasket (with or without anti-stick graphite)
- Tempseal compressible refractory seals
- VG Graphite high temperature seals
Metal Tight Gaskets
VESUVIUS SEALBIND™ Metal Tight mortar gaskets are used primarily in the joint between slide gate top plates and inner nozzles. This pre-packaged mortar gasket provides an easy to use, safe, reliable gasket which is always " fresh from the packet ". There is no wastage and the joint is always the correct thickness. The gasket is made to exacting tolerances to suit the customers' gate system.