Alumina carbon refractory material is the kind of carbon composite refractory material which’s raw materials are alumina and carbon and added with pitch, resins or other organic binders. In most cases, other materials such as SiC, Si and so on are added into the raw material to improve the performance. By production craft, alumina carbon refractory materials can be divided into unburned alumina carbon refractory material and burned alumina carbon refractory material.
Unburned alumina carbon refractory material belongs to carbon bonded refractory material, has better anti-oxidation property than magnesia carbon bricks, and has excellent Na2O series slag corrosion resistance, so are widely used in iron liquid pretreatment equipments such as blast furnace, iron ladle and so on. Sintered alumina carbon refractory material belongs to ceramic bonding refractory material, are usually used as sliding gate bricks, ladle shroud, sub-entry nozzle and monoblock stopper of continuous casting sliding nozzle system.
Alumina Carbon Refractory Material Physiochemical Index
Item
Sintered ACSP-A
Sintered ACSP-B
Monoblock stopper
Ladle shroud
Al2O3 % ≥
67
71
60
46
F.C ≥
7
7
28
32
Apparent porosity %≤
8
8
13
16
Bulk densityg/cm3 ≥
2.7
2.8
2.6
2.7
Cold crushing strength Mpa ≥
79
89
25
27
High temperature rupture strength (1400℃, 0.5h) ≥
8
9
—
—
Cold rupture strength Mpa ≥
—
—
8
9.2
Thermal shock resistance (times) ≥
—
—
10
10
1. Alumina Carbon Sliding Plate Bricks
Alumina carbon sliding plate(ASCP) bricks is the functional refractory material for continuous casting, are widely used in sliding nozzle systems of electric furnace, converter, refinery steel ladle and continuous casting tundish, as the switch to control flow rate and flow quantity of steel liquid. Alumina carbon sliding plate bricks should have good high temperature strength, excellent corrosion resistance, scouring resistance and thermal shock resistance, as well as dimensional accuracy.
Alumina carbon bricks properties
Alumina carbon bricks have excellent slag corrosion resistance and thermal shock resistance.
Compared with magnesia carbon refractory material , alumina carbon sliding gate bricks have better alkali(Na2O) corrosion resistance and TiO2 slag corrosion resistance.
Sintered alumina carbon bricks can form silicon carbide by reaction under high temperature, so there are two bonding methods: carbon bonding and ceramic bonding. Therefore, sintered alumina carbon bricks have good mechanical property, not only play the role of traditional refractory material but also structure functional material.
2. Alumina Carbon Ladle Shroud
In most cases, alumina carbon ladle shroud is set on when steel ladle moves above the tundish, without preheating or only has un-sufficient preheating, so ladle shroud should have excellent thermal shock resistance, and carbon content in ladle shroud should relatively high, generally between 20% and 40%.
3. Alumina Carbon Sub-Entry Nozzle
Alumina carbon sub-entry nozzle is the key link of continuous casting, it’s service life determines continuous casting time and steel quality. The carbon content of alumina carbon sub-entry nozzle is about 30%. To avoid crack during using, sub-entry nozzle should be preheated before using. Two lethal factors that affect sub-entry nozzle service life are slag line part corrosion and Al2O3 blockage.
4. Monoblock Stopper
Monoblock stopper has the same using condition and with ladle shroud, but monoblock stopper is preheated with sub-entry nozzle simultaneously, there is no big thermal shock problem. Stopper Head scouring erosion is the main damage reason. So measures such as adding additives, decrease granularity, controlling sintering temperature, adding steel fiber and so on can be took to improve the quality. The carbon and silicon carbide content is about 30%.
