Refractory materials for sliding nozzles: nozzle block bricks; upper and lower slide plates; upper nozzles; lower nozzles; drainage sand for nozzles. I shared the skateboard with you in the front, and now I have sorted out the physical and chemical indicators and usage methods of the water inlet and the water outlet, cleaning methods and the factors that affect the water outlet and the water outlet. In addition, there is drainage sand for the nozzle.
Refractory material for sliding nozzle-upper nozzle
The upper nozzle brick is directly installed in the ladle nozzle seat brick. When the molten steel flows through the upper nozzle under high temperature, the chemical erosion and erosion of molten steel and molten slag and the mechanical damage caused during installation make the upper nozzle require long life, resistance to molten steel and slag erosion. , Scouring. Aluminum and carbon are commonly used in domestic water outlet bricks, and their service life is related to factors such as steel grade, amount of steel passing and casting time. There are many CaO-C nozzle bricks used abroad. The bricks are formed by isostatic pressing, and the apparent porosity of CaO sand is required to be <5%. Compared with the original Al2O3-C quality nozzle, the CaO-C quality nozzle is characterized by no blockage, no cracks, and 30% melting loss rate in use, while the Al2O3-C quality nozzle has no cracks but The blockage is more serious, and the melting loss rate is 3.3%.
Advantages of CaO-C upper nozzle
(1) The reactivity of CaO sand and C in a high-temperature vacuum reduction atmosphere is small, maintaining the structural strength of the nozzle and improving the corrosion resistance of the nozzle;
(2) CaO sand reacts with Al2O3 in molten steel to produce CaO·Al2O3 and 3CaO·Al2O3 and other low-melting substances flowing down with molten steel, effectively preventing the clogging of the nozzle;
(3) CaO sand has the function of adsorbing sulfur, phosphorus, oxygen and other non-metallic inclusions in molten steel, and has the function of purifying molten steel.
Clean the water inlet during use
Analysis of the factors affecting the water inlet
- The performance of the water inlet material itself
- Water inlet size and wall thickness
- The user’s judgment and understanding of the safety of the water inlet
- Self-opening rate of drainage sand, maintaining the level of oxygen burning, etc.
- Other factors that affect the life of the ladle, such as slag line, breathable bricks, nozzle block bricks, etc., will also limit the further use of the upper nozzle
Refractory material for sliding nozzle-drain
The drain is mainly used to control the flow and injection rate of molten steel, and it is required to have good erosion resistance at high temperatures, good volume stability at high temperatures, and a certain degree of self-melting. The damage factors of the spout include: corrosion and erosion of molten steel and molten slag; cracking or fracture caused by sudden temperature changes; melting loss caused by oxygen burning. The material requires good corrosion resistance. For example, high-aluminum and fused silica can be used for casting ordinary carbon steel; when casting steel with higher manganese content, aluminum-carbon, magnesia and other drains can be selected. In order to improve the thermal shock resistance of the drain, the drain is installed in the iron sleeve to prevent cracking. Should try to avoid burning oxygen to start pouring. The drain uses high-aluminum, aluminum-carbon and aluminum-zirconium-carbon, and its service life is 1 time and 2~3 times respectively.
Analysis of Factors Affecting the Sewage
- The performance and quality of the drain material itself
- The level of installation and operation of the drain
- Self-opening rate of drainage sand
- Maintain the level of oxygen burning, etc.
- Other factors that affect the life of the ladle, such as ladle slag line, breathable bricks, nozzle block bricks, etc., will also limit the further use of the drain