The ladle is an important equipment in the casting process, used to load and transport high-temperature molten iron. However, due to the particularity of its working environment, the ladle often faces severe wear and high-temperature corrosion, resulting in a short life. Therefore, how to improve the life of the lining refractory castable of the ladle has important practical significance.
1. Ladle medium
The ladle consists of a shell and a lining. The shell is riveted and welded by steel plates, and the lining consists of a working layer + a coating layer. The working layer is cast and formed with high-temperature resistant castables, the working lining thickness is 100~150mm, and the coating layer thickness is 10~15mm.
2. Product status and problems
When the molten iron is transported in the ladle, the lining is subjected to high temperature, thermal shock, mechanical wear and chemical erosion of slag and iron; when pouring out the molten iron, the molten iron impact surface is more corroded. At the same time, the ladle works under high and low temperature alternation. The longer the interval period, the more serious the damage to the lining. Therefore, the lining of the ladle should generally be made of refractory materials that are resistant to corrosion, high in strength, and resistant to thermal shock.
During the inoculation treatment in the ladle, the molten iron moves violently, which aggravates the erosion of the lining. The slag on the surface of the molten iron is aggregated and bonded by a casting slag remover. During the slag removal process, the slag becomes sticky and easily hangs on the lining wall, making it difficult to clean. In addition, the scouring of the stirred molten iron and the temperature fluctuations caused by intermittent operation aggravate the damage of the refractory castable in the lining of the ladle, especially in the slag line.
3. Optimization and selection of refractory material castables and other materials for the lining of the ladle
(1) The working layer of the ladle is cast with a low-moisture, low-cement alumina-based material, which has the following advantages and characteristics: ① Excellent anti-stripping ability ② Excellent cold and hot strength ③ Thermal shock resistance
(2) The repair material of the working layer of the ladle uses phosphoric acid as a binder and an alumina-based repair refractory material. This product has high plasticity and is more suitable for repairing thinner layers. It also contains organic fibers, which makes it easier to dry. It has the following advantages and characteristics. ① Thermal shock resistance ② Abrasion resistance and corrosion resistance ③ Suitable for ferrous and non-ferrous metals
(3) The coating layer of the ladle uses carbon-containing repair refractory castable. This material has good adhesion and can be used for thin layer repairs of molten iron contact parts such as ladles in the foundry industry. It can also be used as a coating material for the ladle to effectively improve the slag sticking of the ladle. It has the following advantages and characteristics: ① Direct use, easy construction ② Good adhesion ③ Excellent anti-slag sticking performance.
4. Ladle repair method
(1) Ladle repair method:
The ladle to be repaired should be cooled for 4 hours first, then the sticky slag around the ladle slag line should be cleaned, and repair phosphoric acid should be used as a binder for 4 hours. After the repair is completed, the surface is coated with carbon-containing repair refractory mud and baked for 2 hours. It can be put online for standby.
(2) Ladle unpacking process: Unpack the ladle that needs to replace the lining castable. First, cool the ladle in water for 8 hours. After the ladle is completely cooled, unpack it. After cleaning, you can use the ladle castable to pour the ladle. After pouring, dry it in the shade for 48 hours to ensure that the water in the ladle is completely evaporated. After drying in the shade, apply carbon-containing repair refractory mud on the surface, and finally bake it for 72 hours before putting it online for use.
