Refractories Slide Gate Plate

Types and working principles of sliding plates: The sliding nozzle device is composed of upper and lower sliding plates made of refractory materials and a mechanical driving structure, and is installed outside the bottom of the ladle. The upper sliding plate is fixed and the lower sliding plate is movable. According to the action mode of refractories slide gate plates, it can be divided into three categories: 1) Linear reciprocating type: 2) Linear propelling type: 3) Rotary type. By driving the pull rod, the refractories slide gate plate slides back and forth in a straight line. When the casting holes on the upper and lower refractories slide gate plate bricks are staggered, the upper nozzle hole is filled with drainage sand, and the steel ladle can be loaded with steel; when the casting holes overlap, the drainage sand flows out automatically, and then Pouring, and the pouring speed can be controlled by the degree of overlap of the casting holes.

The sliding plate is a key component that determines the function of the sliding nozzle and plays a role in controlling and regulating the flow of molten steel. Due to the repeated contact of the slide plate with high-temperature molten steel (especially the casting hole part), the corrosion is serious and the use conditions are harsh. The refractories slide gate plate is required to have good properties such as high strength, corrosion resistance, and peeling resistance. During the pouring process, it is ensured that molten steel cannot leak between the refractories slide gate plates. The refractories slide gate plate must have the following properties

(1) Sliding surface flatness <0.05mm

(2) High mechanical strength

(3) Strong resistance to erosion by molten steel and molten slag;

(4)Excellent antioxidant properties

(5) Good thermal shock stability.

The sealing protection of the ladle sliding nozzle is mainly at the connection between the upper nozzle and the upper slide plate, and the lower slide plate and the lower nozzle. During the pouring process, generally after pouring one or two furnaces of molten steel, the lower slide plate and drain outlet must be replaced and reassembled. The sealing protection uses fiber or clay sealing pads to ensure the high cleanliness of the molten steel and the uniformity of the internal quality of the cast slab.

burn into refractories slide gate plate

In the fired aluminum carbon sliding plate, not only the organic binder is carbonized and coked during the firing, forming a carbon bond in the brick, but also the additives, such as metallic silicon, can combine with the carbon to form Sic when reduced and fired at <1300°C. , and a ceramic bond is formed within the brick body. Therefore, there is a dual bonding system of ceramic bonding and carbon bonding in the fired aluminum carbon sliding plate. It significantly improves the strength of the refractories slide gate plate, and even after the carbon is burned out during use, it can maintain sufficient residual strength because it is a ceramic bonding system. After the refractories slide gate plate is burned, it is usually soaked in oil. Vertical or horizontal vacuum-pressurized oil immersion devices are generally used in oil immersion. After the slide is preheated, put it into the oil immersion tank, and evacuate it to a vacuum degree of 650mmHg or above, introduce heated tar or asphalt, and pressurize the oil to 8~16kgf/cm2 or higher to make the tar or asphalt Being sucked into the open air holes of the refractories slide gate plate. The cast holes in the refractories slide gate plate can be made during molding, or they can be formed into a whole plate without holes and then drilled later. Most people think that drilling is beneficial to improve the quality of the refractories slide gate plate. In addition, wrapping and hooping the refractories slide gate plate with thin iron sheets is considered an important measure to ensure the safe use of the refractories slide gate plate. It can prevent the refractories slide gate plate from breaking during use, and because this metal hoop is wrapped very tightly, it has limitations. The propagation of cracks in materials, especially the effect of crack opening.

High performance refractories slide gate plate

It is a non-burning aluminum carbon refractories slide gate plate with relatively simple process, low cost and good use effect. The ingredients of this kind of refractories slide gate plate are similar to those of fired refractories slide gate plates. It uses raw materials such as corundum, mullite, corundum, flake graphite, silicon carbide and silicon powder, and adds phenolic resin as a binder. After mixing, molding, heat treatment and mechanical processing That is the finished product. Compared with fired aluminum carbon refractories slide gate plates, unburned refractories slide gate plates do not require firing, oil immersion and retort heat treatment during manufacturing, which simplifies the production process, but the strength is lower and the porosity is slightly higher. Practice has proved that the non-burning sliding plate has good effect when used on the ladles of medium-sized converters and electric furnaces, and some even surpass the burning oil-immersed sliding plate.

How to install and use refractories slide gate plates

The amount and hardness of the fire clay between the slide plate and the nozzle should be appropriate to make the joint uniform and of suitable strength to increase the self-opening rate of the nozzle, avoid oxygen burning and drainage, reduce the oxidation of the slide plate and the hole expansion to prevent the nozzle from "turning" when the molten steel is poured. The occurrence of "slagging" phenomenon should be reduced to reduce the erosion of slag on the sliding plate surface. When controlling the flow of continuous casting steel and closing the operation after pouring, the stroke 1 should be saved by blowing oxygen to remove the residual steel and prevent the residual steel from being improperly operated and causing excessive expansion of the sliding plate.