Spheroidizing inoculation device for centrifugally casting molten iron of nodular cast iron pipe

Abstract

A spheroidizing inoculation device for centrifugal casting of molten iron of a nodular cast iron pipe comprises a sprue cup, a throat pipe, a runner and a molten iron casting device, the bottom of the sprue cup is connected with the throat pipe, an outlet of the throat pipe is connected with the runner, and a wire feeding device and the molten iron casting device are arranged above the sprue cup; the molten iron pouring device comprises a molten iron ladle and a molten iron pouring mechanism, and the molten iron ladle is connected with the molten iron pouring mechanism. In the centrifugal casting process of the nodular cast iron pipe, a nodulizing inoculant is fed into the throat pipe through a core-spun yarn, molten iron is continuously fed into the core-spun yarn when entering the throat pipe, a nodulizing agent enters the throat pipe along with the molten iron, and the molten iron carries the nodulizing agent to absorb the nodulizing inoculant in the process of flowing through the throat pipe to achieve nodulizing inoculation. The nodulizing inoculant is absorbed in the throat pipe in the process of flowing along with iron liquid in a cored wire mode, nodulizing inoculation along with flow is achieved, the absorptivity of the nodulizing inoculant is improved, the nodulizing technological process is shortened to the maximum extent, and nodulizing decline is avoided.

Description

Technical Field

[0001] This utility model relates to a device for spheroidizing and inoculating molten iron during the centrifugal casting process of ductile iron pipes, and belongs to the field of ductile iron pipe production technology. Background Technology

[0002] In the current ductile iron pipe production process, the spheroidization and inoculation treatment of molten iron is completed through a specially set up spheroidization treatment station, and the following process technologies are generally adopted.

[0003] 1. Pouring Method: Suitable for processing large quantities of molten iron, typically exceeding 3 tons per batch. Applicable to alloy spheroidizing agents with a magnesium content <15%. Uses a pit or dam-type spheroidizing ladle. For molten iron volumes of 0.5–3 tons and temperatures between 1400–1430℃, the spheroidizing agent particle size should be 10–30 mm, with a powder mass fraction not exceeding 10%. First, place the spheroidizing agent at the bottom of the ladle, then cover it with an inoculant. Pour in 1 / 2–2 / 3 of the molten iron initially. When boiling is nearly complete, add more molten iron and skim off the slag.

[0004] 2. Cover ladle method, suitable for alloy spheroidizing agents with magnesium content <15%. A cover ladle is installed on the pouring ladle to receive molten iron, and the flow rate of molten iron injected into the ladle is controlled by the diameter of the bottom gate of the ladle.

[0005] 3. Subcontracting method, suitable for pure magnesium or magnesium coke spheroidizing agent with 43% magnesium content. The reaction chamber is made of graphite clay; it can treat molten iron with sulfur content of 0.3% at a processing temperature of 1400-1500℃.

[0006] 4. Wire feeding spheroidizing method: Suitable spheroidizing agents contain 20%-45% magnesium, 0-6% rare earth elements, 1.0%-3.0% calcium, and 40%-70% silicon, with the remainder being iron. An automatic wire feeder evenly feeds the cored wire (containing the spheroidizing agent) into the molten iron. The cored wire is a thin iron tube with a thickness of 0.2-0.4 mm, filled with the spheroidizing agent. 25-30 m of cored wire is needed to spheroidize 1 ton of molten iron, with a Mg absorption rate of 40%-50%.

[0007] The problems with the above-mentioned spheroidizing technology are: high consumption of spheroidizing inoculant; absorption rate of spheroidizing agent is less than 50% during the process; fumes are generated, requiring large-volume fans and dust collectors; and the long turnover time of molten iron makes it prone to spheroidization degradation.

[0008] If spheroidization and inoculation could be completed during the casting process of ductile iron pipes, it would greatly simplify the molten iron handling process, reduce the consumption and discharge of spheroidizing agents, shorten the pipe casting production process, improve production efficiency, and reduce production costs. However, such a technology is currently lacking. Utility Model Content

[0009] To address the problems existing in the current spheroidizing inoculation technology for molten iron, this utility model provides a spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes, which features a short process, low spheroidizing agent consumption, and high production efficiency.

[0010] The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes in this utility model adopts the following technical solution:

[0011] The device includes a pouring cup, a throat, a flow channel, and a molten iron pouring apparatus. The bottom of the pouring cup is connected to the throat, and the outlet of the throat is connected to the flow channel. A wire feeding device (wire feeder) and a molten iron pouring apparatus are installed above the pouring cup. The inner diameter of the throat is adapted to the molten iron pouring flow rate required for casting pipe forming.

[0012] The molten iron pouring device includes a molten iron ladle and a molten iron pouring mechanism, with the ladle connected to the pouring mechanism. The molten iron ladle is fan-shaped. The molten iron ladle and the pouring mechanism are mounted on a mobile carriage, which has drive wheels at its bottom. The drive wheels are placed on a travel track, and the mobile carriage moves back and forth along a predetermined route on the travel track. The mobile carriage is equipped with a sliding rail, on which the molten iron ladle is placed and hinged to the mobile carriage via a hinge pin.

[0013] The molten iron pouring mechanism employs a gear transmission mechanism, including a motor, gears, and a gear ring. The motor is mounted on a mobile vehicle, the gear is mounted on the motor's shaft, and the gear ring is positioned on the outside of the molten iron ladle, meshing with it. The motor drives the molten iron ladle to rotate through the meshing of the gear and gear ring, causing it to tilt and pour out the molten iron. The tilt angle of the molten iron ladle is controlled by adjusting the motor's speed and rotation time, thus achieving the pouring out of the molten iron.

[0014] The mobile vehicle is equipped with the wire feeding device and the pouring cup. The wire feeding device (wire feeder) allows the cored wire to be inserted into the throat tube.

[0015] The flow channel extends into the mold, which rotates under the drive of a rotating device. A cored wire is inserted into the throat tube via a wire feeding device. Molten iron from the ladle is poured into the pouring cup, while the wire feeding device continuously feeds and mixes the cored wire with the molten iron. The outer layer of the cored wire melts, and the spheroidizing inoculant is absorbed as it flows with the molten iron in the throat tube, thus achieving in-flow spheroidizing inoculation. The magnesium sulfide particles generated during this process (produced by the spheroidizing inoculant) float to the inner wall of the cast tube during high-speed centrifugal casting, without affecting the quality of the tube.

[0016] The pouring speed of the ladle is determined by maintaining a certain liquid level in the pouring cup; the feed speed of the core wire is matched with the rotation speed of the molten iron ladle, and the calculation is based on the proportion of spheroidizing inoculant added to the molten iron.

[0017] This invention utilizes a cored wire method to allow the spheroidizing inoculant to be absorbed as it flows with the molten iron in the throat, achieving in-flow spheroidizing inoculation. This improves the absorption rate of the spheroidizing inoculant, minimizes the spheroidizing process flow, avoids spheroidizing degradation, reduces the amount of spheroidizing inoculant required, and increases production efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to this utility model.

[0019] Among them: 1. Cored wire, 2. Wire feeder, 3. Pour cup, 4. Throat, 5. Top opening, 6. Hinge, 7. Molten iron, 8. Molten iron ladle, 9. Gear, 10. Moving car, 11. Sliding rail, 12. Moving table, 13. Flow channel, 14. Rail, 15. Tube mold, 16. Rotating device. Detailed Implementation

[0020] like Figure 1 As shown, this utility model discloses a spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes, comprising a pouring cup 3, a throat 4, a flow channel 13, and a molten iron pouring device. The bottom of the pouring cup 3 is connected to the throat 4, and the outlet of the throat 4 is connected to the flow channel 13. A wire feeder 2 and the molten iron pouring device are arranged above the pouring cup 3. The flow channel 13 is an open-topped channel. The inner diameter of the throat 4 is adapted to the molten iron pouring flow rate required for pipe forming. The inner diameter and length of the throat are matched with the molten iron pouring efficiency to ensure that the cored wire and molten iron achieve spheroidizing inoculation within the throat. The wire feeder 2 is existing technology.

[0021] The molten iron pouring device includes a molten iron ladle 8 and a molten iron pouring mechanism. The molten iron ladle 8 is connected to the molten iron pouring mechanism, and both are mounted on a moving carriage 10. A sliding rail 11 is provided on the moving carriage 10. The molten iron ladle 8 is placed on the sliding rail 11 and hinged to the moving carriage 10 via a hinge shaft 6. The molten iron ladle 8 is connected to the molten iron pouring mechanism. The molten iron pouring mechanism drives the molten iron ladle 8 to rotate around the hinge shaft 6, realizing the pouring of molten iron. The sliding rail 11 guides the movement of the molten iron ladle 8. The molten iron ladle 8 is fan-shaped, enabling quantitative pouring. The moving carriage 10 is mounted on a moving platform 12 via drive wheels at its bottom. A steel rail 14 (travel track) is provided on the moving platform 12, and the moving carriage 10 reciprocates along the steel rail 14 on the moving platform 12.

[0022] The molten iron pouring mechanism employs a gear transmission mechanism, including a motor (not shown in the figure), gear 9, and a gear ring. The motor is mounted on the moving carriage 10, gear 9 is mounted on the motor's rotating shaft, and the gear ring is positioned on the outer arc of the molten iron ladle 8, meshing with the gear ring. The motor is a servo motor, driving gear 9 to rotate. Through the meshing of gear 9 and gear ring, the molten iron ladle 8 is driven to rotate, causing it to tilt and pour out the molten iron.

[0023] The wire feeder 2 and the pouring cup 3 can also be mounted on the mobile carriage 10.

[0024] The operation process of the above-mentioned molten iron spheroidizing inoculation device is as follows.

[0025] The spheroidizing agent cored wire 1 is placed on the wire feeder 2, and the wire feeder 2 causes the cored wire 1 to extend into the throat 4 of the pouring cup 3. Before the molten iron 7 enters the throat 4 (before the pouring begins), the cored wire 1 fed into the throat 4 is the same length as the throat 4 to ensure the initial spheroidizing and inoculation effect of the molten iron.

[0026] The mobile carriage 10 travels along the rail 14 on the moving platform 12 to the molten iron melting furnace and pours the molten iron 7 into the molten iron ladle 8. The mobile carriage 10 moves toward the tube mold 15, so that the flow channel 13 extends into the tube mold 15, and the tube mold 15 rotates under the drive of the rotating device 16.

[0027] The motor in the molten iron pouring mechanism is started, driving the molten iron ladle 8 to rotate upwards via gear transmission, causing the molten iron 7 to pour into the pouring cup 13 from the upper opening 5. Simultaneously, the wire feeder 2 continuously feeds the cored wire 1 into the throat tube 4, where it mixes with the molten iron. The outer layer of the cored wire melts, and the spheroidizing inoculant is absorbed as the molten iron passes through the throat tube 4, thus achieving in-flow spheroidizing inoculation. The magnesium sulfide particles generated during this process (produced by the spheroidizing inoculant) float to the inner wall of the cast pipe during high-speed centrifugal casting, without affecting the quality of the pipe body.

[0028] The tilting speed of the molten iron ladle 8 is based on maintaining the predetermined liquid level height of the pouring cup 3, and the feeding speed of the wire feeder 2 conveying the cored wire 1 is calculated according to the molten iron flow rate and the proportion of spheroidizing inoculant added.

[0029] The particulate matter can be precipitated before solidification by appropriately increasing the temperature of the molten iron and increasing the rotation speed of the mold 14.

Claims

1. A spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes, characterized in that: It includes a pouring cup, a throat, a trough, and a molten iron pouring device. The bottom of the pouring cup is connected to the throat, the outlet of the throat is connected to the trough, and a wire feeding device and a molten iron pouring device are installed above the pouring cup.

2. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 1, characterized in that: The molten iron pouring device includes a molten iron ladle and a molten iron pouring mechanism, with the molten iron ladle connected to the molten iron pouring mechanism.

3. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 2, characterized in that: The molten iron ladle is fan-shaped.

4. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 2, characterized in that: The molten iron ladle and molten iron pouring mechanism are mounted on a mobile vehicle, and the bottom of the mobile vehicle is equipped with drive wheels, which are placed on a travel track.

5. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 4, characterized in that: The mobile vehicle is equipped with a sliding rail, and the molten iron ladle is placed on the sliding rail and hinged to the mobile vehicle via a hinge shaft.

6. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 2, characterized in that: The molten iron pouring mechanism adopts a gear transmission mechanism, including a motor, a gear and a gear ring. The motor is mounted on a mobile vehicle, the gear is mounted on the motor shaft, and the gear ring is located on the outside of the molten iron ladle, with the gear meshing with the gear ring.

7. The spheroidizing inoculation device for centrifugally casting molten iron into ductile iron pipes according to claim 4, characterized in that: The wire feeding device and the pouring cup are installed on the mobile vehicle.

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