Argon Insert Upper Nozzles for Tundish of Slab Caster

Argon Insert Upper Nozzles are specialized tundish flow-control refractories designed for slab continuous casting.

Installed at the bottom of the tundish and working with the stopper system and downstream nozzle, the upper nozzle provides a controlled passage for molten steel while the argon insert enables controlled argon purging around the nozzle bore.

For slab caster operators, the main concern is not simply whether an upper nozzle can withstand high temperature. The nozzle must also maintain stable steel flow, resist erosion and corrosion, reduce the risk of nozzle clogging, and remain compatible with the tundish and stopper system.

Qingdao Dongye High Temperature Materials Co., Ltd. manufactures argon insert upper nozzles for slab casters according to customer drawings, tundish design, casting conditions, and required dimensions.

What Is an Argon Insert Upper Nozzle?

An argon insert upper nozzle is a refractory upper nozzle installed in the tundish of a continuous casting machine.

The upper nozzle forms part of the molten-steel flow path between the tundish and the downstream nozzle system. In a stopper-controlled tundish, the opening between the stopper and upper nozzle is adjusted to regulate the steel flow rate.

The argon insert adds a gas-purging function to the upper nozzle.

When argon is supplied through the designed gas channel or porous insert, the gas can form a controlled protective/purging zone around the nozzle bore. This can help reduce the adhesion and accumulation of non-metallic inclusions on the inner surface of the nozzle.

This function is particularly important when casting steel grades that are prone to nozzle clogging.

Why Use an Argon Insert Upper Nozzle?

Nozzle clogging is one of the practical problems that can affect continuous casting stability.

During casting, non-metallic inclusions can accumulate on the inner wall of the upper nozzle and gradually restrict the steel flow passage. Argon purging of the upper nozzle is a commonly used approach for reducing alumina buildup, although it does not eliminate clogging under all operating conditions.

For slab casters, an argon insert upper nozzle is therefore designed to address several requirements at the same time:

· Stable molten steel passage

· Controlled argon distribution

· Reduced inclusion buildup

· Lower risk of nozzle clogging

· Resistance to molten-steel erosion

· Resistance to slag and chemical corrosion

· Thermal shock resistance

· Reliable dimensional fit

· Compatibility with the tundish stopper system

How Does Argon Purging Work in the Upper Nozzle?

The basic working principle is straightforward:

Tundish → Argon Insert Upper Nozzle → Downstream Nozzle → Submerged Entry Nozzle → Mold

During casting, molten steel passes through the upper nozzle while argon is introduced through the designed gas-purging structure.

The argon creates a controlled gas environment near the nozzle bore. Depending on the design and operating conditions, this can help reduce the adhesion of inclusions to the refractory surface and improve the stability of the steel flow passage.

Research on argon blowing through tundish upper nozzles has shown that argon flow rate and casting speed can affect liquid-steel flow behavior and argon bubble movement. Therefore, the argon system should be considered together with the actual casting conditions rather than selecting a nozzle independently.

Key Performance Requirements

1. Stable Steel Flow

The upper nozzle is part of the tundish flow-control system.

Its internal bore, working-end geometry, and dimensional accuracy need to remain stable during casting so that the steel flow can be controlled predictably.

The upper nozzle also works together with the stopper. The condition of the contact and flow-control area can directly influence the stability of molten-steel flow.

2. Effective Argon Purging

The argon insert must provide a suitable gas path around the working area.

An appropriate gas distribution design helps maintain controlled argon flow instead of creating uncontrolled leakage or uneven gas distribution.

The required argon configuration should be matched to the customer’s tundish and gas-supply system.

3. Anti-Clogging Performance

One of the main reasons customers select an argon insert upper nozzle is to reduce the risk of nozzle bore blockage caused by non-metallic inclusions.

This is particularly relevant for steel grades where alumina buildup can restrict the nozzle passage.

However, nozzle clogging is affected by many factors, including steel composition, inclusion characteristics, casting temperature, argon flow conditions, nozzle material, and casting practice.

The nozzle should therefore be selected as part of the complete casting process rather than considered as an isolated component.

4. Thermal Shock Resistance

The upper nozzle is exposed to rapid heating when the tundish begins casting.

The refractory structure must therefore withstand the thermal transition between the preheated tundish condition and molten steel service.

Good thermal shock resistance helps reduce the risk of cracking during installation and casting.

5. Erosion and Corrosion Resistance

The internal bore is continuously exposed to flowing molten steel.

The working area may also be affected by slag and other aggressive materials.

For this reason, material selection should consider the customer’s steel grade, casting sequence, temperature, and expected operating conditions.

6. Dimensional Accuracy

The upper nozzle must fit correctly with the tundish, stopper, and downstream nozzle arrangement.

Important dimensions may include:

· Overall height

· Outside diameter

· Bore diameter

· Working-end dimensions

· Stopper contact geometry

· Argon inlet position

· Argon channel configuration

· Installation dimensions

For replacement products, an existing drawing or sample is strongly recommended.

Argon Insert Upper Nozzle Structure

The exact structure can vary according to the customer’s tundish design and casting requirements.

A typical product may include:

· Refractory upper-nozzle body

· High-performance inner working area

· Argon insert or porous gas-permeable section

· Argon gas channel

· Gas inlet connection

· Metal casing or supporting structure where required

· Customized installation geometry

Some upper-nozzle designs also use zirconia-containing working areas to improve resistance to erosion and corrosion. Such material configurations are commonly used in tundish upper nozzles, but the appropriate composition should be determined according to the customer’s actual casting conditions.

Argon Insert Design for Slab Casters

Slab casting places specific requirements on tundish flow-control components.

Compared with simply supplying a standard upper nozzle, the product needs to match:

· Slab caster configuration

· Tundish capacity

· Stopper arrangement

· Casting speed

· Steel grade

· Casting temperature

· Argon supply system

· Downstream nozzle design

· Required casting sequence

The argon insert design should therefore be confirmed together with the complete tundish system.

How to Choose the Right Argon Insert Upper Nozzle

1. Steel Grade

Tell us which steel grades you are casting.

This is important because different steel grades may present different inclusion and nozzle-clogging conditions.

2. Slab Caster Configuration

Please provide the caster type and relevant tundish information.

If available, provide the equipment model, tundish drawing, or existing nozzle drawing.

3. Existing Upper Nozzle Dimensions

For replacement orders, the original product dimensions are particularly useful.

Please provide:

· Outer diameter

· Height

· Bore diameter

· Working-end dimensions

· Installation dimensions

4. Argon System

Please provide information about the existing argon supply and connection arrangement.

This allows the argon insert and gas-channel design to be matched to the actual system.

5. Stopper System

Because the upper nozzle works together with the stopper, the stopper geometry and contact area should be considered when confirming the upper-nozzle design.

6. Casting Problems

If your current nozzle has a specific problem, please tell us.

For example:

· Upper nozzle clogging

· Unstable steel flow

· Excessive erosion

· Cracking during preheating

· Argon leakage

· Uneven argon distribution

· Short casting sequence

· Difficult nozzle replacement

This information is valuable for selecting or modifying the product.

Customized Argon Insert Upper Nozzles

Not every slab caster uses the same tundish design.

Dongye can manufacture argon insert upper nozzles according to confirmed customer requirements, drawings, samples, and equipment dimensions.

Customization can include:

· Overall dimensions

· Bore diameter

· Working-end geometry

· Argon insert position

· Argon channel design

· Gas inlet configuration

· Refractory material selection

· Metal casing configuration

· Packaging requirements

For customers replacing an existing supplier’s upper nozzle, we recommend providing the original drawing or sample so that dimensional compatibility can be checked before production.

Manufacturing and Quality Control

For an argon insert upper nozzle, quality control needs to cover both the refractory component and the argon-purging function.

Our manufacturing and inspection approach focuses on:

· Raw material control

· Controlled mixing and forming

· Thermal processing

· Dimensional inspection

· Working-bore inspection

· Surface inspection

· Argon-channel inspection

· Gas-path integrity where applicable

· Finished-product inspection

· Packaging and transportation protection

The exact inspection requirements can be agreed with the customer according to technical specifications and purchasing standards.

Application in the Slab Continuous Casting Process

The argon insert upper nozzle is one component of a complete continuous casting flow-control system.

A typical arrangement can be understood as:

Ladle → Ladle Shroud → Tundish → Stopper → Argon Insert Upper Nozzle → SEN → Mold

Each component has a different function.

The upper nozzle connects the tundish flow-control system with the downstream nozzle system. Its performance therefore needs to be considered together with the stopper, SEN, tundish condition, and argon supply.

This system-based approach is important when troubleshooting nozzle clogging or unstable steel flow.

Troubleshooting Upper Nozzle Problems

Why does the upper nozzle become clogged?

Clogging can be associated with the accumulation of non-metallic inclusions on the nozzle bore.

The risk can be influenced by steel composition, inclusion characteristics, temperature, refractory material, casting practice, and argon-purging conditions.

Argon purging can help reduce alumina buildup, but the correct argon flow and nozzle design must be matched to the specific casting process.

Why is the steel flow unstable?

Possible causes include:

· Stopper and nozzle wear

· Bore restriction

· Uneven erosion

· Inclusion buildup

· Incorrect nozzle dimensions

· Improper stopper/nozzle matching

· Unstable argon conditions

The complete tundish flow-control system should be inspected rather than replacing the nozzle without identifying the underlying cause.

Why does the upper nozzle crack?

Cracking can be associated with thermal shock, improper preheating, installation stress, mechanical damage, or unsuitable refractory selection.

The actual cause should be evaluated according to the installation and operating conditions.

Can the argon insert prevent all nozzle clogging?

No.

Argon purging is intended to help reduce inclusion adhesion and buildup, but nozzle clogging is affected by multiple metallurgical and operating factors.

The argon insert should be regarded as one part of the overall anti-clogging strategy.

Why Choose Dongye Argon Insert Upper Nozzles?

Continuous Casting Refractory Experience

Dongye focuses on refractory products for continuous casting and related high-temperature metallurgical applications.

Our product range includes tundish upper nozzles, monoblock stoppers, ladle shrouds, submerged entry nozzles, and other flow-control refractories.

Application-Oriented Product Selection

We focus on the customer’s actual casting conditions instead of treating every tundish upper nozzle as a standard product.

Customized Manufacturing

Products can be manufactured according to drawings, samples, dimensions, and confirmed equipment requirements.

Quality-Controlled Production

Dimensional accuracy, refractory quality, and the functional requirements of the argon insert are considered during production and inspection.

International Supply Capability

Dongye serves domestic and overseas customers and can support technical communication, customized manufacturing, packaging, and export shipment requirements.

Request a Customized Argon Insert Upper Nozzle

If you are looking for an argon insert upper nozzle for a slab caster, send us your existing nozzle drawing, product dimensions, tundish information, or casting problems.

Our technical team can evaluate:

· Upper nozzle dimensions

· Argon insert configuration

· Refractory material requirements

· Stopper compatibility

· Casting conditions

· Anti-clogging requirements

We can then confirm the appropriate product specification before production.

Contact Qingdao Dongye High Temperature Materials Co., Ltd. for customized argon insert upper nozzles for slab continuous casting.