Snref China Bottom Argon Blowing Segment Purge Plug for Steel Plant
SNREF purging plug is characterized by their high strength, good erosion resistance and corrosion resistance, high blowing rate and good safety. They are widely used for continuous casting ladles and refining ladles.
Working Principle and Functions of Ladle Porous Plug
The porous plug (also called permeable brick or gas purging plug) at the bottom of a steel ladle is a critical functional component in steelmaking, primarily used for gas stirring and composition homogenization during secondary refining. Below is a detailed explanation of its core working principles and functions:
I. Structure and Working Principle
1. Structural Composition
- Porous refractory material: Typically made of high-alumina, magnesia, or corundum-based refractory with interconnected micropores (pore size: 0.1-0.5 mm).
- Metal casing: Stainless steel or heat-resistant alloy sleeve to prevent steel penetration and ensure fixation.
- Gas supply system: Connected to argon/nitrogen pipelines at the ladle bottom, with adjustable pressure (0.1-0.5 MPa).
2. Operational Process
1. Gas injection: Inert gas (e.g., argon) permeates through the plug's micropores, forming fine bubbles in molten steel.
2. Bubble ascent: Rising bubbles create turbulence, driving steel circulation ("boiling effect").
3. Homogenization: Stirring ensures uniform temperature/chemical distribution and accelerates inclusion flotation into the slag layer.
II. Core Functions
1. Secondary refining (RH/LF processes)
- Degassing: Removes harmful gases (e.g., [H], [O]; hydrogen content ≤2 ppm).
- Alloy homogenization: Enhances dissolution/diffusion of alloying elements (e.g., Si, Mn).
2. Temperature uniformity
- Mitigates thermal stratification (e.g., "cold steel" at ladle bottom during continuous casting).
3. Inclusion removal
- Bubbles transport non-metallic inclusions (e.g., Al2O3) to the slag layer (removal efficiency >60%).
4. Process adaptability
- Adjustable gas flow (0.5-10 Nm³/min) for varied steel grades (e.g., intense stirring for low-carbon steel).
Conclusion
As the "heart" of ladle refining, porous plugs enable efficient purification and homogenization, directly impacting steel quality (e.g., +5-8% nondestructive testing pass rate) and cost efficiency. Advancements in materials and automation will further revolutionize steelmaking.
-Slot Plug(slit plug)
Slot plug is the most common structure in purging plug.
The gas channel could be designed and customized according to actual on-site using conditions, including refining steel grade,
refining workmanship, ladle capacity, temperature, hydrostatic pressure of liquid steel etc.
This can achieve the best blowing effect for purging plugs, ensure the longest service life, safety, stability and best air
permeability.
-Porous plug
Porous plug has better porosity and permeability.
Production technology is adding carbon-containing compound into mixture, since carbon-containing compound can burn out without
residue at low temperature, so we adopt low temperature burning out intermediate materials to get the initial porosity.
In porous type plug, inside distributes interpenetrating gas channels in different sizes.
When blowing stop, the steel and slag from ladle will infiltrate into the deep areas of the plug, to form a secure layer on working surface.
-Segment Plug
The segment plug is preferably made of good anti-stripping materials, the block body is not easy to occur fracture, with longer service life. The cracks between different plates will not expand, so this segment plug design can avoid failure of bottom blowing caused by tranverse brick fracture.
Application characteristics: In order to adapt to more and more strict refining conditions(especially special steel), and to meet the requirements of increasing ladle life, the volume of plug becomes bigger and bigger. However the traditional slit type plug has single material and single structure, easy to cause the phenomenon of tranverse fracture and failure of air blowing. Our researched segment plug has successfully soved the problem of fracture existing in traditional slit plug. Significantly increasing the stability of refining process, ensuring the realization and improvement of quality refined steel.
-Hybrid Plug
Secondary refining technology is the most important part in steelmaking process
It can adjust the steel alloy type and liquid temperature.
Purging plug and block is the key functional component to make this process carried out.
As the ladle tends to develop in larger scale, the melting temperature and time have been improved significantly, which makes the
using environment for refractory materials more and more strict. Therefore, it is necessary to further improve the performance of
purging plugs and blocks to meet the increasing demands in current steelmaking technology
-Overall breathable brick:
This product adopts high purity raw materials, through vibration casting and low temperature heating process workmanship.
Function is blowing argon gas via purge plug to ladle.
With the feature of high strength, good thermal stability, erosion resistance and abrasion resistance.
Widely used in steel plants LF, LF-VD, CAS-OB refining ladle
We manufacture various high-quality ladle refractory according to the clients' needs , and to ensure the stability and accountability of the quality.
Technical data will be customized according to your steel making condition.
| Chemical and Physical Properties |
SNLWB-85 |
SNLWB-90 |
SNLWB-95 |
| Al2O3 +MgO % min |
85 |
90 |
95 |
| Cr2O3 (C) % min |
0 |
2.5 |
2.5 |
| Apparent porosity g/cm3% max |
15 |
13 |
13 |
| Bulk density g/cm3 % min |
3.0 |
3.05 |
2.9 |
| Normal temperature Compressive strength (MPa) min |
80 |
100 |
100 |
| Breaking strength 1500°C×3hmin |
23Mpa |
Well block and segment plug
| Chemical and Physical Properties |
(Well block) |
(purging plug) |
| AL2O3 % |
>=85 |
>=85 |
| MgO% |
3-5 |
1-3 |
| Cr2O3 % |
----- |
>2.4 |
| Bulk density g\cm3 |
>=3.0 |
>=2.9 |
| Apparent Porosity % |
<=16 |
<=18 |
| Cold crushing strength Mpa |
110ºC*24h |
>=60.0 |
>=80.0 |
| 1500ºC*3h |
>=100.0 |
>=80.0 |
| Refractoriness under load : ºC |
>=1680 |
>=1680 |
| Modulus of rupture 1400ºC *1h Mpa Mpa |
>=15.0 |
>=15.0 |
| Linear change 1500ºC*3h % |
±0.2 |
±0.2 |
| air permeability, m3/hour at P=4 bar |
30M3/H |
Product packaging
1- International standard seaworthy exportable packing.
2- Wooden pallet.
3- Wooden / bamboo case (box).
4- Further packing information will be based on customer's requirements.
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