Argon blowing is usually to build one or several ladle purging plug at the bottom of the pouring ladle or brick ladle. After tapping, blow argon gas through the breathable bricks to cause agitation of the molten steel in the ladle. Argon blowing can promote the floating of emulsified slag droplets and inclusions in steel, and can partially remove the dissolved gas and uniform components in the steel. In the case of continuous casting, the ladle blowing of argon can play a role in adjusting the temperature of the molten steel. Ladle argon blowing is an important steelmaking process, and breathable bricks are an important functional element of this process.
1.Material and performance of ladle purging plug
The materials of ladle permeable bricks are mainly sintered magnesia, magnesia chromium, high aluminum and corundum. It is a better choice to use corundum as the main crystal phase of the breathable brick.
To realize the argon blowing process, the air-permeable brick must have good high temperature resistance, corrosion resistance, thermal shock resistance, high temperature volume stability and high strength, stable operation, good air permeability, accurate dimensions, and less molten steel penetration. In the actual field use results, it is found that the non-oxide bonded corundum breathable brick has the characteristics of good thermal shock resistance, non-wetting with molten steel, high blow-through rate during use, easy to clean by oxygen blowing, and low corrosion rate. At the same time, the service life has also been significantly improved.
2.The choice of the installation position of the breathable brick
When choosing the position of the blowing element at the bottom of the ladle, it should be determined according to the purpose of ladle processing. The air-permeable bricks are installed at the center of the bottom of the ladle and deviated from the center of the ladle (the blowing point is at the 1/2-1/3 radius from the center of the ladle). The blowing effect on the molten steel is different, and the argon blowing at the bottom of the ladle is beneficial to the ladle slag. The reaction between gold is conducive to the desulfurization reaction of the top slag; and the eccentric bottom blowing of argon is conducive to the mixing and temperature homogenization in the ladle and the floating of inclusions.
3.Technical requirements for the use of breathable bricks
(1)Good air permeability. Air permeability is one of the important parameters to measure the quality of ladle air permeable bricks.
(2)High temperature corrosion resistance.
(3)High temperature wear resistance.
(4)Good thermal shock resistance.
(5)Simple installation, safe and reliable are required.
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More details about Ladle Purging Plug
What are the different types of purging plugs?
What are the different types of purging plugs?
The purging plugs are generally classified into two types. One is porous plug that has characteristic of excellent bubbling reliability. Another is slit plug (alias directional type plug) and it has characteristic of long life. Table 1 shows the comparison between the two types of purging plug.
What is ladle purging plugs?
Ladle purging plugs always come in a steel cone in order to ensure a gas tight connection between plug and purging gas supply. For installation a refractory mortar is put onto the steel cone and subsequently the plug is mounted into the block/ladle bottom.
Why argon is purged at the bottom of the ladle?
During ladle refining process, argon gas is purged into the ladle for stirring the molten steel bath to eliminate thermal and composition gradients and to achieve inclusion flotation. Operating parameters like purging location, porous plug configuration and argon flow rate primarily affect liquid steel refining.
Which gas is used for purging in ladle?
Argon; Dual gas purging is often done in a ladle to accelerate the refining operations in steel industries. The purged gas, mainly argon imparts momentum to the molten metal and establishes a turbulent recirculating flow in the melt, which generates shear stresses on the ladle walls.