An argon stirring lance is a cylindrical device submerged into molten steel from the top of a ladle to inject argon during secondary refining. As the gas disperses through the melt, it promotes the homogenisation of temperature and chemical composition while supporting the removal of impurities. To perform these functions reliably under demanding ladle furnace conditions, the lance must be designed to withstand high temperatures, thermal shock, and continuous exposure to molten steel and slag.
Daiwa Argon Stirring Lance is engineered for these conditions, featuring a calorized steel shell, a rich alumina refractory coating, and a calorized core steel pipe.
If you are a ladle furnace operator, process engineer, or procurement professional specifying or evaluating top-lance stirring for the first time, this guide is for you. It examines top-entry argon stirring lances in the context of secondary refining, looking at their construction layer by layer, the published dimensions, and the function each design choice serves in operation.
When steel is tapped into a ladle it is not a uniform liquid. It is stratified.
Temperature differs between the top of the bath and the bottom. Alloy additions sit concentrated near where they were added rather than distributed through the volume. Dissolved hydrogen and nitrogen remain in solution. Deoxidation products and entrained slag stay suspended in the steel rather than rising to the slag layer.
None of these conditions correct themselves within the time available. A ladle left to stand loses temperature without becoming more uniform. The mechanism that solves all four problems simultaneously is controlled gas stirring and that is the duty a top lance performs.
It is a lance, not a nozzle. The distinction matters: a nozzle is built into the ladle and stays there, while a lance is a separate item lowered into the ladle, held for the treatment, then withdrawn. That makes it a consumable with a service life rather than a fixture with a refractory campaign.
Argon is used because it is inert. It does not react with the steel, does not add nitrogen or oxygen to the bath, and leaves nothing behind except the effect of its passage.
Most ladles are equipped for stirring through a porous plug set into the floor. Gas enters from below and rises through the full depth of the bath.
A top lance approaches from the opposite direction. It is lowered through the open top of the ladle and submerged into the melt, releasing argon at the required depth. Ladle furnace argon injection through a top lance therefore does not depend on the condition of the bottom plug - which is why emergency stirring in secondary refining appears among its listed applications. When a plug blocks or wears, the lance restores capability without taking the ladle out of service.
Three effects follow, and they occur together rather than in sequence:
Deoxidation and desulfurization are also supported, because both depend on contact between the steel and the slag and circulation is what renews that contact.
The lance is built in three concentric layers. Each protects the one inside it.
The outermost layer is a calorized steel casing. It is the part that meets the ladle environment directly and takes the first exposure during immersion and withdrawal.
Beneath the shell sits a rich alumina refractory coating, specified at Al₂O₃ = 80%. This is the thermal barrier between the ladle environment and the pipe carrying the gas. Alumina-rich refractories are used in ladle service because of how they behave under the thermal and chemical conditions inside a steel ladle.
At the centre is the calorized core steel pipe, which carries argon from the supply connection to the outlet. This is the component whose dimensions determine gas delivery and whose length determines how deep the lance can be immersed.
|
Parameter |
Published value |
|
Core pipe outside diameter |
48.6-60.5 mm |
|
Core pipe wall thickness |
3.6-14.2 mm |
|
Core pipe length |
4,000-6,000 mm |
|
Total lance length |
5,500-7,550 mm |
|
Refractory |
Rich alumina, Al₂O₃ = 80%, properly dried |
|
Shell |
Calorized steel casing |
|
Outlet options |
Straight-Through Exit (Ø19.0 mm), Porous Plug Exit, Tri-Port Exit |
The gap between core pipe length and total lance length - 1,500 mm at the lower end of the range and 1,550 mm at the upper end - accounts for the assembly beyond the pipe itself. When checking whether a lance suits a ladle, total lance length is the figure to work from, not core pipe length.
Refractory materials absorb moisture from the air during storage. When a refractory carrying retained moisture is immersed in molten steel, that moisture converts to steam almost instantly and expands, which can damage the coating from the inside.
This is why drying is treated as a quality checkpoint at manufacture rather than a site procedure, and why storage conditions after delivery matter. A lance stored in a damp warehouse for months is not in the same condition as one stored dry.
Ladle work combines molten steel, compressed gas and overhead handling. Four requirements apply to the lance itself.
Sound construction and verified refractory condition. Inspect the refractory coating before every use. Cracking, spalling or visible damage means the lance does not go into the ladle.
Uniform wall thickness. With a core pipe wall of 3.6-14.2 mm supporting a total assembly up to 7,550 mm long, even wall thickness is what allows the lance to resist bending and breaking while extended over a ladle.
Clean, oil-free and grease-free surface. Lances must arrive clean and be stored so they stay clean and dry. Contamination picked up in the warehouse is carried into the ladle.
Rigorous quality control. Daiwa lance products are manufactured under ISO 9001 quality management and ISO 14001 environmental management, and inspected to JIS.
Handling equipment must be rated for the full assembled length. Immersion depth should be confirmed against ladle depth and freeboard before the lance is lowered, not judged during the operation. Personal protective equipment and adequate ventilation are required for heat and fumes.
Daiwa Lance products are manufactured in Tan Thuan Export Processing Zone, District 7, Ho Chi Minh City, Vietnam, using Japanese manufacturing technology and engineering discipline, backed by JIS. Quality management follows ISO 9001 and environmental management follows ISO 14001.
The company exports to more than 52 countries with full export documentation. For ladle metallurgy consumables - where a lance is specified against a particular ladle rather than bought from a catalogue shelf - documentation that accurately records what was supplied matters for repeat ordering as much as for customs.
The answer to what is an argon stirring lance is a three-layer assembly doing one job: delivering inert gas to a defined depth in a ladle, reliably, for the duration of a treatment. The calorized shell handles the environment, the 80% alumina refractory handles the heat, and the calorized core pipe delivers the gas. Specify against total lance length and ladle depth, confirm the refractory has been properly dried, and inspect it before every use.
Are you evaluating top-entry argon stirring lances for ladle furnaces, or do you need a supplementary stirring solution for instances where bottom porous plugs fail?
Daiwa offers Argon Stirring Lances featuring a three-layer construction and a wide range of diameters, lengths, and tip configurations to suit specific operational conditions.
Contact Daiwa Lance for advice on specifications based on ladle depth, stirring requirements, and refining goals, or to request a quote for your plant's needs.
It injects argon into molten steel during secondary refining. The dispersed gas homogenises temperature and composition, assists removal of dissolved hydrogen and nitrogen, supports deoxidation and desulfurization, and provides emergency stirring capability in secondary refining when bottom stirring is unavailable.
Because it is inert. Argon does not react with the steel and does not add nitrogen or oxygen to the bath. Its function is mechanical and physical - creating circulation, providing bubble surfaces for inclusions to attach to, and giving dissolved gases somewhere to diffuse into - rather than chemical.
Three layers. The outer layer is a calorized steel casing. Beneath it is a rich alumina refractory coating specified at Al₂O₃ = 80%, which requires proper drying. At the centre is a calorized core steel pipe that carries the argon from the supply connection to the outlet.
Core pipe length is 4,000-6,000 mm and refers to the pipe carrying the gas. Total lance length is 5,500-7,550 mm and covers the complete assembly. When checking whether a lance suits a particular ladle, work from total lance length, since that is what determines reach and handling requirements.
No - the two are complementary. A bottom plug stirs from the floor of the ladle; a top lance is lowered in from above and works independently of the plug's condition. That independence is why emergency stirring in secondary refining is listed among the lance's applications. Plants running critical grades commonly maintain both.
Established since 1997, Daiwa Lance has positioned ourselves as a pioneer in thermic cutting and oxygen lancing technology. Based in Ho Chi Minh City, Vietnam, we have been providing quality customer service and products with advanced Japanese technology.
We maintain the highest quality standards with ISO 9001:2015, ISO 14001:2015, and JIS G standards certifications. We have also expanded our reach globally, exporting to over 55 countries worldwide.
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