The upper slide is fixed and the lower slide is movable. According to the sliding action mode, it can be divided into three categories: 1) linear reciprocating; 2) linear propulsion; 3) rotary. By driving the pull rod, the slide plate is linearly reciprocated. When the casting holes on the upper and lower sliding blocks are staggered, the drainage hole is filled with the drainage sand, the ladle can be loaded with steel,when the casting holes are coincident, the drainage sand automatically flows out. Casting, and the casting speed can be controlled by the extent to which the cast holes partially overlap.
Skateboard is the key component to determine the function of the sliding nozzle, which controls the flow of molten steel. Due to the repeated contact of the skateboard with high-temperature molten steel (especially the part of the cast hole), the erosion is severe and the conditions of use are harsh. The skateboard is required to have good performances such as high strength, erosion resistance and peeling resistance. During the pouring process, the sliding water can not be leaked in the sliding plate, and the sliding plate must have the following properties:
1.The smoothness of the sliding surface is ≤0.05mm.
2.High mechanical strength.
3.Strong resistance to molten steel and slag.
4.Excellent oxidation resistance.
5. Good thermal shock stability.
The sealing protection of the ladle sliding nozzle is mainly at the upper water inlet and the upper sliding plate, the lower sliding plate is connected with the water outlet. During the pouring process, the lower slide and the drain must be replaced and reassembled after each furnace or two furnaces of molten steel. The seal protection uses a fibrous or clay seal to ensure the high cleanliness of the molten steel and the uniformity of the internal quality of the cast.
In the fired aluminum carbon slide, not only the organic binder is carbonized and coked in the firing, carbon is formed in the brick, and the additive, such as metal silicon, can be combined with carbon to form SiC when reduced and fired at <1300 ° C. And forming a ceramic bond in the brick body.
Therefore, there is a dual bonding system of ceramic bonding and carbon bonding in the firing aluminum carbon skateboard. It significantly increases the strength of the skateboard and maintains sufficient residual strength after it has been burned out in use due to its ceramic bond system.
After the skateboard is fired, it is generally necessary to carry out oil immersion. Vertical or horizontal vacuum-pressure oil immersion devices are generally used in oil immersion. After the slide is preheated, put it into the oil-immersed tank, and vacuum it to a vacuum of 650mmHg or more, introduce heated tar or asphalt, and pressurize the oil to a pressure of 8~16kgf/cm2 or higher to make tar or asphalt. It is sucked into the open air hole of the slide. The casting hole in the sliding plate can be made at the time of molding, or can be formed into a non-porous integral plate and then drilled later. Most people think that drilling is good for improving the quality of skateboards.
In addition, wrapping the hoop around the skateboard with thin iron is considered to be an important measure to ensure the safe use of the skateboard. It can prevent the cracking of the skateboard during use, and because the metal hoop is tightly packed, it has limitations. Crack propagation in the material, especially the effect of crack opening.
High performance skateboard is a non-burning aluminum carbon skateboard with simple process, low cost and good effect. The composition of the skateboard is similar to that of the fired skateboard. The raw materials such as sapphire, mullite, corundum, flake graphite, silicon carbide and silicon powder are added, and the phenolic resin is added as a binder. After mixing, forming, heat treatment and mechanical processing. That is the finished product. Compared with the fired aluminum carbon slide, the non-burning slide does not require firing, oil immersion and dry distillation heat treatment in the manufacturing process, which simplifies the production process, but the strength is low and the porosity is slightly higher. It has been proved by practice that the non-burning skateboard is used well on the ladle of the medium-sized converter and the electric furnace, and some even exceed the burning oil-immersed skateboard.
l. The fire mud between the skateboard and the nozzle should have moderate dosage and soft hardness, so that the joint is uniform and the strength is suitable.
2. Increase the self-opening rate of the nozzle, avoid the oxygenation and reduce the oxidation and reaming of the skateboard.
3. Prevent the occurrence of “slag” phenomenon at the nozzle when the molten steel is cast, and reduce the erosion of the slag on the skateboard surface.
4. The stroke should be saved when the continuous casting and pouring steel is controlled and the closing operation is completed.
5.Blowing oxygen to remove residual steel, the residue to prevent improper operation caused by excessive expansion of the slide.
Skateboard Damage Factor
1.Cracks and chipping around the cast hole due to thermal shock. Micro cracks and damage must be produced when the high temperature molten steel is initially in contact with the cold refractory material. Therefore, it is extremely important to improve the thermal shock resistance of the skateboard material.
2.Erosion and erosion of molten steel and slag. The anti-erosion and scouring ability of the skateboard will significantly affect its life. Erosion mainly refers to the reaction of Mn, MnO, FeO, CaO and other components in the molten steel with the sliding material. The SiO2 in the refractory material is easy to react, reducing the SiO2 content is advantageous against erosion. The carbon in the product prevents the intrusion and reaction of corrosive oxides, and the oxidation prevention of carbon is dominant.
3.The wear of the sliding refractory material in the sliding, especially when the sliding plate has certain damage, and the solidified steel causes the sliding of the sliding plate when sliding. Therefore, the strength of the skateboard should be increased. In addition, the material should be kept smooth with a low porosity to reduce penetration and penetration of molten steel, and tar and asphalt impregnation to improve surface lubricity and keep the surface smooth.
