A runner tip for a runner

Abstract

The utility model discloses a flow nozzle applied to horizontal centrifugal casting field's one kind. The outer circumferential surface spiral winding resistance wire of flow nozzle pipe, this resistance wire is equipped with the ceramic short pipe cover, and its outer layer is wrapped fire -retardant cotton layer, and the fire -retardant cotton layer and the steel pipe inner wall between are casting material layer, and the mounting end welding flange plate of steel pipe, and the end through -hole inserts ceramic pipe, and the resistance wire is connected out flow nozzle with ceramic pipe. The utility model utilizes resistance wire direct heating flow nozzle pipe, does not use combustible gas, and the outer layer is heat -insulated, and flow nozzle pipe heating efficiency is high, especially applicable to small foundry.

Description

Technical Field

[0001] This utility model is applied in the field of centrifugal casting and relates to a horizontal centrifugal molten metal flow channel package, specifically a flow nozzle with electric heating installed on the flow channel package. Background Technology

[0002] In centrifugal casting, steel pipes with large length-to-diameter ratios are typically produced using horizontal centrifugal casting. This requires a ladle to convert the downward pouring flow of molten steel into a horizontal flow, which is then guided into a horizontal mold by a spout, where it is centrifugally formed into a cast steel pipe. To reduce the temperature drop of the molten steel during its flow in the ladle and to ensure the pouring temperature before entering the mold, thus preventing poor forming, the ladle and spout need to be heated to a high temperature, typically red-hot, before pouring. This allows the temperature of the molten steel in the ladle to be set as the pouring temperature. Currently, ladle heating often employs exothermic combustion of combustible gases. After combustion, the flow of these gases releases most of the heat into the surrounding environment, resulting in very low heat utilization efficiency for the ladle and spout. This heating method is suitable for steel mills where combustible gases are inexpensive, but it is not suitable for foundries, especially small foundries, as it actually increases the cost of ladle heating.

[0003] The runner is an indispensable key component of the casting ladle (or tundish, or runner) for centrifugally cast steel pipes. It directly affects the safety of centrifugal casting and the quality of the cast steel pipe, and is a crucial factor to consider in avoiding steel spillage accidents or improving the quality of cast steel pipes. There are not many patent applications related to runners. CN201420487506.5 describes a quick-replacement runner for centrifugally casting small-diameter thin-walled pipe blanks, including a front runner, a rear runner, and a connecting screw. The front and rear runners are connected by the connecting screw. If the front runner burns out, the connecting screw can be removed and the front runner replaced. CN201821007001.9 describes a casting ladle runner, which is used in centrifugal casting under inert gas protection. The nozzle and casting vessel are separate units, employing a conical seal. The nozzle uses two nested steel pipes for sealing, with an inert gas cavity in the middle. This inert gas cavity is connected to an inert gas inlet pipe. The nozzle has an inert gas tube mold outlet and an inert gas baffle outlet. For easy assembly and disassembly, the nozzle and casting vessel are fixedly connected using wedges or quick-change fasteners. None of the above patents address the issue of nozzle heating.

[0004] To save on the baking cost of the nozzle, this invention uses electric heating to heat the nozzle. Utility Model Content

[0005] The technical problem solved by this utility model is to provide a flow nozzle for a flow channel bag, which has a built-in resistance wire and uses electric heating to improve heating efficiency.

[0006] The technical solution adopted in this utility model is as follows: the flow nozzle for the flow channel includes a flow nozzle tube, a resistance wire, a steel pipe, a castable layer, a refractory cotton layer, and a ceramic short tube. The resistance wire is spirally wound around the outer circumference of the flow nozzle tube, and the resistance wire is fitted with a ceramic short tube, which allows for bending and deformation of the resistance wire; the outer layer of the resistance wire is wrapped with a refractory cotton layer; the space between the refractory cotton layer and the inner wall of the steel pipe is a castable layer; a flange is welded to the installation end of the steel pipe.

[0007] Furthermore, the installation end of the steel pipe is machined with a through hole, into which a ceramic tube is inserted, and a resistance wire and a short ceramic tube are installed inside the ceramic tube.

[0008] Furthermore, the resistance wire is wound in a bidirectional spiral or in a combination of unidirectional spiral and straight sections, to facilitate the external lead-out of the resistance wire at one end of the nozzle. The straight section is located within the refractory cotton layer, between the refractory cotton layer and the castable layer, between the castable layer and the inner wall of the steel pipe, or close to the outer wall of the steel pipe.

[0009] Furthermore, the outer circumferential surface of the nozzle is coated with a refractory mud layer to increase the uniformity of the force on the outer circumferential surface of the nozzle.

[0010] Furthermore, the outer surface of the nozzle tube is provided with a spiral groove, which matches the winding of the resistance wire to reduce the workload of nozzle preparation.

[0011] The beneficial effects of this invention are: This invention utilizes resistance wire to directly heat the nozzle tube, with an outer heat-insulating layer, resulting in high heating efficiency. This nozzle tube heating method is particularly suitable for small foundries, solving the problem of low-cost nozzle tube heating, and is easy to operate, effectively reducing the temperature drop during molten steel pouring. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the main structure of Example 1, and also... Figure 2 AA section view; Figure 2 for Figure 1 A schematic diagram of the left-side view structure; Figure 3 for Figure 2 A top-view structural diagram; Figure 4 A schematic diagram of a structure for winding resistance wire; Figure 5 This is a schematic diagram of another structure for winding resistance wire; Figure 6 This is a schematic diagram of the main structure of Example 3; Figure 7 This is a schematic diagram of the main structure of Example 4; Among them: 1-nozzle, 2-resistance wire, 3-flange, 4-steel pipe, 5-castable layer, 6-refractory cotton layer, 7-ceramic short pipe, 8-ceramic pipe, 9-aerogel cotton layer, 10-refractory cotton strip. Detailed Implementation

[0013] The terms "inner" and "outer" refer to their distance from the center line of the spout; "inner" means closer to the center line and "outer" means farther away. Example

[0014] The nozzle structure in this embodiment is shown in the attached figure. Figure 1-3 As shown, it includes a nozzle 1, a resistance wire 2, a flange 3, a steel pipe 4, a castable layer 5, a refractory cotton layer 6, a ceramic short pipe 7, and a ceramic pipe 8.

[0015] The nozzle tube 1 is a finished tube made of purchased refractory material, which is usually used for rapid prototyping of sand mold direct sprues. Its inner hole is used for the flow of molten metal during pouring. This utility model is also used for the flow of molten metal, and the function is the same.

[0016] The outer circumference of the nozzle tube 1 is spirally wound with a resistance wire 2, which is then encased in multiple ceramic short tubes 7. The resistance wire 2 is used for heating when energized, while the ceramic short tubes 7 are used to insulate the resistance wire and accommodate its bending and deformation. In this way, the resistance wire can be bent arbitrarily to meet the requirements for deformation or reversal.

[0017] The outer layer of the resistance wire 2 is wrapped with a fire-resistant cotton layer 6, which is then bound and secured with fire-resistant rope or thin iron wire. The fire-resistant cotton layer 6 serves two purposes: one is heat insulation, preventing the heat generated by the resistance wire from dissipating outwards; the other is to insulate and secure the resistance wire, preventing it from short-circuiting.

[0018] The outer layer of the refractory cotton layer 6 is the castable layer 5, which is a refractory material that provides strength for high-temperature casting of the nozzle.

[0019] The outside of the castable layer 5 is a steel pipe 4, which provides constraint for the casting of the castable layer 5 and also facilitates the welding and fixing of the flange 3, which is used for fastener connection with the outer wall of the flow channel.

[0020] At the installation end of the steel pipe, a through hole is machined, and a ceramic tube 8 is inserted into the through hole. The resistance wire 2 and the short ceramic tube 7 are installed inside the ceramic tube 8. The resistance wire 2 is connected to the outlet nozzle to facilitate the electrical connection of the resistance wire 2.

[0021] To achieve external mounting of the self-flow nozzles at both ends of the resistance wire, the following method can be used: Figure 4 The bidirectional helical winding method can also be adopted. Figure 5The method involves a unidirectional spiral winding combined with a straight section. The straight section should ideally be within the refractory cotton layer 6, or between the refractory cotton layer 6 and the castable layer 5, or between the castable layer 5 and the inner wall of the steel pipe 4. When the nozzle outer diameter is small and the baffle center hole is large, the straight section can also be tightly attached to the outer wall of the steel pipe 4 to provide protection against the adverse effects of steel spillage or high temperatures.

[0022] In this embodiment, during the manufacturing of the nozzle, the resistance wire 2 of the ceramic short tube 7 is evenly wound around the nozzle tube 1, then wrapped with a refractory cotton layer 6, and bound with thin iron wire. This is then inserted into the steel pipe 4 of the welded flange 3. The center of the steel pipe 4 should ideally be aligned with the center of the nozzle tube 1. Next, castable refractory is poured between the refractory cotton layer 6 and the inner wall of the steel pipe 4, and tamped down layer by layer to prevent large displacement of the resistance wire. The castable refractory is then dried and set aside for later use.

[0023] In this embodiment, the nozzle is fixed to the outer wall of the casting box with fasteners. The nozzle tube is connected to the casting channel inside the casting box. Then, the resistance wire is energized and heated, and the heating state is maintained until the casting is ready. The resistance wire voltage is 220V, the power is 1-1.5KW, and the nozzle tube is red-hot in 2-3 hours. Example

[0024] In Example 1, there is a gap between the nozzle tube 1 and the resistance wire and refractory cotton layer, as shown in the attached figure. Figure 1 and attached Figure 3 As shown, the uneven stress on the outer circumference of the nozzle tube can cause cracks or breaks when molten steel flows through it if the nozzle tube 1 has poor resistance to extreme cold and heat. This molten steel can then flow into the gap between the nozzle tube and the refractory cotton layer, damaging the resistance wire or causing a short circuit. To prevent this, a refractory mud layer is applied to the outer circumference of the nozzle tube 1. After the refractory mud layer dries, the resistance wire is then wound around it. The purpose of the refractory mud layer is to ensure relatively uniform stress on the outer circumference of the nozzle tube. Even if cracks or breaks occur in the nozzle tube, the refractory mud layer protects the resistance wire and prevents damage. After pouring, the nozzle is replaced. Example

[0025] Currently, aerogel cotton has the best thermal insulation performance. In this embodiment, aerogel cotton layer 9 is used as the thermal insulation layer, as shown in the attached figure. Figure 6 As shown. The spirally wound resistance wires are separated by fire-resistant cotton strips 10. The fire-resistant cotton strips 10 serve to separate the insulating resistance wires. Other flexible insulating and high-temperature resistant materials can also be used instead. Compared to Example 1, the outer circumferential surface of the nozzle tube 1 is subjected to relatively uniform force in this embodiment, so it is not necessary to coat its outer surface with refractory mud as in Example 2. This not only reduces the workload in nozzle preparation, but also saves the drying time of the refractory mud layer. Example

[0026] The structure of this embodiment is as shown in the attached figure. Figure 7 As shown, the difference from the above embodiment is that the outer surface of the nozzle tube 1 is provided with a spiral groove for winding the resistance wire 2. The spiral groove is preferably matched with the winding of the ceramic short tube 7 and the resistance wire 2. That is to say, the refractory cotton strip part in embodiment 3 is integrated with the nozzle tube, which reduces the workload of nozzle preparation, and the heating of the nozzle tube is relatively uniform. However, it is necessary to specially order a nozzle tube with a spiral groove.

[0027] This invention utilizes resistance wire to directly heat the nozzle tube, with external insulation to prevent heat loss, resulting in high heating efficiency. The power-on and power-off operation is convenient, making it particularly suitable for foundries without excess gas, such as small foundries. It effectively solves the problem of low-cost nozzle tube heating, and the convenient heating operation helps ensure the pouring temperature of molten steel entering the mold.

Claims

1. A flow nozzle for a flow channel package, characterized in that: It includes a nozzle tube (1), a resistance wire (2), a flange (3), a steel pipe (4), a castable layer (5), a refractory cotton layer (6), and a ceramic short tube (7); the outer circumference of the nozzle tube (1) is spirally wound with the resistance wire (2), and the resistance wire (2) is fitted with a ceramic short tube (7); the outer layer of the resistance wire (2) is wrapped with a refractory cotton layer (6); the refractory cotton layer (6) is between the steel pipe (4) and the castable layer (5); the flange (3) is welded to the installation end of the steel pipe (4).

2. The flow nozzle for a flow channel bag according to claim 1, characterized in that: The steel pipe (4) has a through hole at its installation end, into which a ceramic tube (8) is inserted. The ceramic tube (8) contains a resistance wire (2) and a ceramic short tube (7).

3. The flow nozzle for a flow channel bag according to claim 1, characterized in that: The resistance wire (2) is wound in a bidirectional spiral or in a unidirectional spiral combined with a straight section; the straight section is located within the refractory cotton layer (6), or between the refractory cotton layer (6) and the castable layer (5), or between the castable layer (5) and the inner wall of the steel pipe (4), or close to the outer wall of the steel pipe (4).

4. The flow nozzle for a flow channel bag according to claim 1, characterized in that: The outer circumferential surface of the nozzle (1) is coated with a refractory mud layer.

5. A flow nozzle for a flow channel bag according to claim 1, characterized in that: The refractory cotton layer (6) is replaced by aerogel cotton (9), and the resistance wires (2) are separated by refractory cotton strips (10).

6. The flow nozzle for a flow channel bag according to claim 1, characterized in that: The outer surface of the nozzle tube (1) is provided with a spiral groove, which is matched with the winding of the resistance wire (2).

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