What Is A Ladle Furnace ?

Ladle furnace is an out-of-furnace refining technology using arc heating under vacuum conditions.

It is a furnace that places the molten steel initially smelted in a general steelmaking furnace into a special ladle for refining.

The ladle furnace is used to refine the molten steel melted in the primary smelting furnace (electric arc furnace, open hearth, converter),

And it can adjust the temperature of molten steel, process buffering, and meet the important metallurgical equipment of continuous casting and continuous rolling.

Ladle furnace is one of the main equipment for refining outside the furnace.

Main Functions of Ladle Furnace:

1. The function of heating and heat preservation of molten steel.

2. Argon stirring function.

3. Vacuum degassing function.

Design:

Ladle furnace mainly includes ladle, furnace cover, arc heating system, vacuum system and feeding device.

Ladle:

Sitting on a ladle car. 

The optimal ratio between the depth of the molten pool and the diameter of the pool surface, that is, H/D is 1.0 to 1.4, the water-cooled flange ring of the water-cooled furnace cover is installed on the outer edge of the ladle furnace mouth, which is used for sealing, and the bottom is equipped with a slipper for pouring steel. 

The LF moving nozzle is r/2～r/3 away from the furnace wall (r is the radius of the furnace bottom), and there is a permeable brick for argon blowing.

Furnace Cover:

It is used to seal the ladle mouth, maintain a strong reducing atmosphere in the furnace and prevent the molten steel from dissipating heat. 

There is a water-cooled furnace cover on the ladle mouth.

The inner side of the furnace cover is poured with refractory material. The furnace cover is provided with a lifting mechanism according to the process requirements.

Arc Heating:

The molten steel is heated by arc light generated between the graphite electrode and the molten steel.

This heating method has less heat dissipation, reduces heat radiation and erosion of the furnace lining by arc light, and stabilizes the current.

The heating rate of molten steel can reach 4℃/min.

Vacuum System:

It consists of vacuum furnace cover, vacuum pump, vacuum exhaust pipe and dust removal equipment.

An air or nitrogen gas inlet is set on the vacuum exhaust pipe to adjust the vacuum degree in the furnace or to break the vacuum by charging at the end of the refining process.

The top of the vacuum furnace cover is provided with an exhaust port and a peep hole for vacuum evacuation, and a sealed water-cooled yellow filling and a lifting mechanism of the vacuum furnace cover are provided at the junction with the ladle mouth.

Feeding Device:

The furnace cover and the vacuum cover are respectively provided with slag-forming agent and alloy adding ports.

The upper part of the furnace cover or vacuum cover is equipped with a hopper, and the charge weighed by the electronic scale enters the ladle furnace through the chute and the charging port.

In order to smelt ultra-low carbon stainless steel, a hole for raising and lowering the oxygen lance is opened in the vertical center of the vacuum furnace cover to blow oxygen to the molten steel to reduce carbon.

Application Areas:

Ladle furnaces are widely used in industry, steel, metallurgy and other industries.

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saleswn@hanrm.com / inquiry66@hanmetallurgy.com ( Daisy )