Pouring method for improving purity of steel ingot

Abstract

The invention discloses a pouring method for improving the purity of a steel ingot, which adopts a bottom pouring method for pouring and comprises the following steps of: 1) hoisting a steel ladle to a pouring truck, and vertically centering an upper sliding plate hole of the steel ladle and a middle pouring pipe; (2) an argon protection device is arranged between a steel ladle collector nozzle and a center injection pipe bowl opening; (3) casting powder is placed in the steel ingot mold; and (4) in the pouring operation process, off-line pouring is carried out firstly, and after drainage sand and steel flow are fully discharged, pouring operation is carried out by returning to a pouring station. According to the method, off-line casting is adopted, casting accidents can be reduced, the working efficiency can be improved, the molten steel quality can be optimized, the casting process can be stabilized, the production benefit can be improved, and the steel ingot quality can be guaranteed. According to the method, the centering device and the laser gradienter are matched for centering, centering can be accurately and rapidly achieved, splashing of molten steel is avoided, the problem that cleaning is difficult is solved, the defects of steel ingot scabbing, subsurface bubbles and the like are reduced, the yield of the molten steel is increased, waste is avoided, and cost is saved.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a casting method for improving the purity of steel ingots. Background Technology

[0002] Zhangxuan Technology Special Materials Research and Development Company mainly produces special materials for high-end products. It strictly requires and precisely calculates the alloy composition and process flow of its steel ingots, which greatly improves the quality of green high-end materials.

[0003] Ingot casting is one of the most difficult and technologically advanced products to manufacture among cast products. Ingot casting is a process in which molten metal is poured into a mold through the ladle's drain port to form a steel ingot. Based on the direction of the molten metal being poured into the ingot, it can be divided into two methods: top pouring and bottom pouring. In top pouring, the molten metal is poured from the top of the ingot mold; in bottom pouring, the molten metal flows through a central pouring pipe and channel into the bottom of the ingot mold, and the ingot gradually takes shape as the molten steel level rises inside the mold.

[0004] The pouring method is adopted by Zhangxuan Special Materials Research and Development Company due to its simplicity, high efficiency, and good ingot surface quality. However, the pouring process is long, which can introduce more inclusions into the molten steel, resulting in lower internal purity of the ingot and affecting the final ingot quality. For example, when the ladle cannot be opened automatically for manual assisted pouring, the mixing of molten steel with the pouring sand, combined with the combustion aid of oxygen, and the falling steel slag and reactants from the pouring sand, can affect the normal pouring of molten steel and cause a decrease in its purity. Furthermore, excessive contact between the molten steel and refractory materials and air during the pouring process is also a key factor affecting ingot quality. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a casting method for improving the purity of steel ingots, so as to improve the quality of steel ingots.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is to use the pouring method for casting, including the following steps: 1) hoisting the ladle to the casting car and aligning the upper sliding plate hole of the ladle with the middle pouring pipe vertically; 2) An argon gas protection device is installed between the ladle drain and the center injection pipe bowl; 3) Place protective slag inside the steel ingot mold; 4) The pouring process begins with pouring outside the line. After the drainage sand and steel flow are fully discharged, the pouring operation is carried out at the pouring station.

[0007] Furthermore, in step 4), the off-line casting adopts the following off-line collection device: including a collection container and a transition bridge; the collection container adopts a container structure with an open top; the transition bridge is a plate structure, mounted between the collection container and the top of the ingot mold and located below the ladle movement path.

[0008] Furthermore, in step 1), centering is performed using a centering device and a laser level. The centering device includes a main rod, an upper positioning rod, a lower positioning rod, and a bowl-shaped cover plate. The upper positioning rod is located at the upper part of the front end of the main rod, and the lower positioning rod is located at the rear end of the upper positioning rod and fixed to the lower part of the main rod. The horizontal distance between the upper and lower positioning rods is the travel distance of the upper and lower sliding plates of the ladle sliding nozzle. The center of the bowl-shaped cover plate is fixed at the bottom of the lower positioning rod, and the size of the bowl-shaped cover plate is consistent with the inner diameter of the bowl on the middle injection pipe.

[0009] Furthermore, the centering process is as follows: the main rod of the centering device is kept horizontal, and the upper positioning rod is inserted into the lower slide plate hole of the ladle; then the reference point of the cross laser emitted by the laser level is aligned with the center position of the bowl on the middle injection tube, and the cursor is moved up to the position of the main rod to observe the horizontal distance between it and the lower positioning rod; the ladle position is moved so that the center of the lower positioning rod coincides with the reference point of the cross laser cursor; finally, the bowl cover plate is placed on the bowl on the middle injection tube.

[0010] Furthermore, the structure of the argon protection device in step 2) includes a protective baffle ring, a base plate, a thermal radiation shielding ring, a sintered filter, and an argon blowing ring. The protective baffle ring is cylindrical with an inner diameter sufficient to accommodate the inlet of the injection tube. The base plate is a circular plate with dimensions matching the protective baffle ring, fixed to the bottom of the protective baffle ring, and has a backflow hole at its center, the size of which matches the drain outlet of the ladle. The thermal radiation shielding ring is cylindrical with a diameter and height smaller than the protective baffle ring and is mounted on the base plate. The sintered filter is a flat ring, positioned between the top of the thermal radiation shielding ring and the protective baffle ring, thus forming an argon rectification chamber at the bottom of the sintered filter. The argon blowing ring is a ring-shaped structure with an argon blowing tube coiled within the argon rectification chamber. The top of the argon blowing ring has a ring of argon blowing holes, and one end of the argon blowing ring is connected to a high-pressure argon source.

[0011] Furthermore, in step 4), the flow rate control rod is used to control the flow rate of the molten steel during the pouring operation; the flow rate control device is an integral rod-shaped structure, including a front horizontal section, an inclined adjustment section and an end horizontal section; the front horizontal section and the end horizontal section are designed to be parallel to each other, and the inclined adjustment section is inclined between the front horizontal section and the end horizontal section; an annular protrusion is provided at the front end of the front horizontal section, and the annular protrusion can be inserted into the hole of the rocker arm (51) of the sliding gate mechanism.

[0012] Furthermore, in step 3), a rotating roller device is used to place the protective slag; the rotating roller device has the following structure: including a base, a support, a drum, a crank handle, and a wire rope; there are two supports, which are fixed on both sides of the base respectively; the drum shaft is rotatably connected between the two supports, the crank handle is set on the outside of one support and connected to the center of the drum; the wire rope is wound on the drum.

[0013] Furthermore, the rotating roller device is also equipped with a marking rod, which is connected between two supports; different color marks are used to segment the marking rod, and the length of the wire rope to be deployed is confirmed to correspond to the color mark segment where the wire rope extends.

[0014] Furthermore, the rotating roller device is also provided with a locking pin; one side of the roller is provided with at least one roller positioning hole, and the bracket on this side is provided with at least one bracket positioning hole, the roller positioning hole and the bracket positioning hole are located on the same circumference; the locking pin can be inserted into the bracket positioning hole and the roller positioning hole.

[0015] Furthermore, the protective slag is placed using the following process: the protective slag is tied with hemp rope and the rope ends are connected to the steel wire rope; the protective slag is moved to the placement point on the upper part of the steel ingot mold using the fixed pulleys on the bottom plate of the casting truck; the handle is turned to release the steel wire rope, and the protective slag is lowered into the steel ingot mold; the hemp rope carbonizes and breaks under the heat radiation inside the steel ingot mold, and the protective slag falls downward and covers the surface of the molten steel; the steel wire rope is then retrieved.

[0016] The beneficial effects of adopting the above technical solution are as follows: the present invention adopts off-line casting, which can reduce casting accidents, improve work efficiency, optimize the quality of molten steel, stabilize the casting process, improve production efficiency, and ensure the quality of steel ingots.

[0017] This invention also utilizes an off-line collection device to effectively implement off-line casting, preventing molten steel splashing and facilitating the normal progress of the casting process. The invention employs a centering device and a laser level for accurate and rapid centering, preventing molten steel splashing, solving the problem of difficult cleaning, reducing defects such as ingot scaling and subcutaneous bubbles, improving molten steel yield, avoiding waste, and saving costs. The invention uses an argon gas protection device to provide comprehensive inert gas protection during molten steel casting, effectively reducing secondary oxidation, improving steel purity, promoting an oxidation-free casting production mode, significantly reducing the degree of oxidation, and improving steel quality. The invention uses a rotating roller device to place the protective slag, ensuring stable and reliable addition of the protective slag 42 to the ingot mold. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a schematic diagram of the overhead crane hoisting the steel ladle and making fine adjustments during alignment with the injection pipe in this invention; Figure 2 This is a schematic diagram of the structure of the off-line collection device described in this invention; Figure 3 This is a schematic diagram of the steel flow rate control device inside the ladle according to the present invention; Figure 4 This is a schematic diagram of the structure during off-line casting as described in this invention; Figure 5 This is a schematic diagram of the structure of the return pouring station outside the casting line described in this invention; Figure 6 This is a schematic diagram of the structure of the pouring station described in this invention for carrying out the pouring operation; Figure 7 This is a schematic diagram of the field use of the steel flow rate control device inside the ladle described in this invention; Figure 8 This is a schematic diagram of the centering device described in this invention; Figure 9 This is a schematic diagram of the centering device described in this invention in use; Figure 10 This is a schematic diagram of the ladle sliding gate's upper and lower sliding plates in the pouring state as described in this invention; Figure 11 This is a schematic diagram of the centering device described in this invention in use; Figure 12 This is a top view of the centering device described in this invention in use. Figure 13 This is a partial schematic diagram of the centering device described in this invention in use; Figure 14 This is a schematic diagram of the argon gas protection device described in this invention; Figure 15 This is a schematic diagram of the argon gas protection device described in this invention in use. Figure 16 This is a schematic diagram of the protective slag placement state of the rotating roller device described in this invention; Figure 17 This is a schematic diagram of the structure of the rotating roller device described in this invention; Figure 18 A schematic diagram of the sliding gate structure of the ladle according to the present invention.

[0020] In the diagram: 1. Overhead crane; 2. Gantry hook; 3. Ladle; 4. Casting car; 5. Collection container; 6. Flow rate control rod; 7. Ingot mold; 8. Central injection pipe; 9. Drainage sand; 10. Transition bridge; 11. Support; 12. Steel flow; 13. Sliding nozzle; 14. Upper positioning rod; 15. Bowl-shaped cover plate; 16. Centering device; 17. Upper sliding plate hole; 18. Lower sliding plate hole; 19. Upper bowl-shaped inlet of the central injection pipe; 21. Laser level; 22. Cross laser; 23. Argon blowing ring; 24. Sintering filter; 25. Thermal radiation shielding ring; 26. Base plate; 27. Protective retaining ring. Argon gas rectifier chamber 28; backflow hole 29; argon gas protection device 30; rear support of slide rail 31; front support of slide rail 32; argon gun 33; counterweight 34; drain outlet 35; central injection pipe bowl 36; rotating roller device 37; rear fixed pulley of base plate 38; front fixed pulley of base plate 39; steel wire rope 40; hemp rope 41; protective slag 42; hook 43; crank handle 44; bracket positioning hole 45; locking pin 46; drum 47; base 48; marking rod 49; segmented coating 50; rocker arm 51; sliding plate pull rod 52. Detailed Implementation

[0021] Figure 1-18 As shown, the casting method for improving the purity of steel ingots adopts the bottom casting method and includes the following steps: 1) The steel ladle 3 is transported to the casting car 4, and the upper sliding plate hole 17 of the steel ladle 3 is aligned with the middle injection pipe 8.

[0022] Figures 8-13 As shown, centering is achieved using a centering device 16 and a laser level 21. The centering device 16 includes a main rod, an upper positioning rod 14, a lower positioning rod, and a bowl-shaped cover plate 15. The main rod is horizontally positioned. The upper positioning rod 14 is vertically positioned and fixed to the upper part of the front end of the main rod. The lower positioning rod is located at the rear end of the upper positioning rod 14, vertically positioned and fixed to the lower part of the main rod. The horizontal distance between the upper positioning rod 14 and the lower positioning rod is the travel distance of the upper and lower sliding plates of the ladle's sliding nozzle. The center of the bowl-shaped cover plate 15 is fixed to the bottom of the lower positioning rod, and the center of the bowl-shaped cover plate 15 is located on the center line of the lower positioning rod. The size of the bowl-shaped cover plate 15 is consistent with the inner diameter of the bowl 19 on the middle injection pipe. The length of the main rod should allow the operator on the operating table to insert the upper positioning rod 14 into the lower sliding plate hole 18 of the ladle.

[0023] Figures 8-13As shown, the centering process is as follows: the center of the connection between the upper positioning rod 14 and the main rod is the centering point A, and the center of the connection between the lower positioning rod and the main rod is the centering point B. The main rod of the centering device 16 is kept horizontal, and the upper positioning rod 14 is inserted into the lower slide plate hole 18 of the ladle; then the reference point of the cross laser 22 emitted by the laser level 21 is aligned with the center position of the bowl 19 on the middle injection tube, and the cursor is moved up to the position of the main rod to observe the horizontal distance from the centering point B; the ladle 3 is moved to make the center of the lower positioning rod coincide with the reference point of the cross laser 22 cursor; finally, the bowl cover plate 15 is placed on the bowl 19 on the middle injection tube.

[0024] 2) Figure 14 , 15 As shown, an argon gas protection device 30 is installed between the ladle drain outlet 35 and the inlet of the central injection pipe 36. The argon gas protection device 30 comprises a protective baffle ring 27, a base plate 26, a thermal radiation shielding ring 25, a sintered filter screen 24, and an argon blowing ring 23. The protective baffle ring 27 is cylindrical, with an inner diameter sufficient to accommodate the inlet of the central injection pipe 36. The base plate 26 is circular, with its outer circumference matching the protective baffle ring 27 and fixed to its bottom. A backflow hole 29 is located at the center of the base plate 26, its size matching the ladle drain outlet 35, and facing upwards directly towards the ladle drain outlet 35 during use. The thermal radiation shielding ring 25 is cylindrical, with a diameter and height smaller than the protective baffle ring 27, and is positioned on the upper part of the base plate 26, with the backflow hole 29 located within the thermal radiation shielding ring 25. The sintered filter 24 is annular, with its inner ring size matching the heat radiation shielding ring 25 and its outer ring size matching the inner wall of the protective baffle ring 27. The sintered filter 24 is positioned between the top of the heat radiation shielding ring 25 and the inner wall of the protective baffle ring 27. Thus, the sintered filter 24, the protective baffle ring 27, the base plate 26, and the heat radiation shielding ring 25 form an annular argon gas rectification chamber 28. The argon blowing ring 23 is formed by an argon blowing tube coiled into a ring shape within the argon gas rectification chamber 28. An argon blowing hole is located at the top of the argon blowing ring 23, and one end of the argon blowing ring 23 is connected to a high-pressure argon gas source. For internal analysis and ease of understanding, Figure 14 The presented state is the opposite of the usage state, and the above spatial relationship is based on... Figure 14 The presented state is described. When the argon gas protection device 30 is in use, the protective baffle 27 faces downwards and is directly opposite the center injection pipe bowl 36, and the backflow hole 29 faces upwards and is directly opposite the ladle drain outlet 35.

[0025] 3) Figure 16 , 17As shown, a rotating rolling device 37 is used to place protective slag 42 inside the steel ingot mold 7. The rotating rolling device 37 has the following structure: it includes a base 48, a support, a drum 47, a crank 44, and a steel wire rope 40; there are two supports, which are fixed on both sides of the base. The drum 47 is rotatably connected between the two supports, and the crank 44 is located on the outside of one support and fixed to the center of the drum 47. The steel wire rope 40 is wound on the drum 47. The rotating rolling device 37 is also provided with a marking rod 49, which is connected between the two supports; different color marks are used to segment the marking rod 50, and the length of the steel wire rope 40 corresponding to the color mark segment where the steel wire rope 40 extends is confirmed. The rotating rolling device 37 is also provided with a locking pin 46; one side of the drum 47 has at least one drum positioning hole, and the support on this side has at least one support positioning hole 45, with the drum positioning hole and the support positioning hole 45 located on the same circumference; the locking pin 46 can be inserted into the support positioning hole 45 and the drum positioning hole. The front end of the wire rope 40 is also provided with a hook 43. The drum may also be provided with a rewinding mechanism.

[0026] Figure 16 , 17 As shown, the protective slag 42 is placed using the following process: The protective slag 42 is bound with hemp rope 41, and the hemp rope 41 is connected to the end of the wire rope 40. The wire rope 40 passes through the bottom plate of the casting car 4, where a fixed pulley 38 is located behind the bottom plate and a fixed pulley 39 is located in front of the bottom plate. The protective slag 42 is moved to the placement point on the upper part of the ingot mold 7 via the fixed pulleys 38 and 39. The handle 44 is turned to release the wire rope 40, lowering the protective slag 42 into the ingot mold 7. The hemp rope 41 carbonizes and breaks under the heat radiation inside the ingot mold 7, causing the protective slag 42 to fall downwards and cover the surface of the molten steel. The operator retracts the wire rope 10 by rotating the handle 44 and moves the hook 43 to the position of the fixed pulley 39 in front of the bottom plate. A rewinding mechanism can also be used to rewind the wire rope 40.

[0027] 4) Figure 2 , Figure 4 , 5 As shown in Figure 6, the casting process begins with casting outside the line. After the drainage sand 9 and steel flow 12 are fully discharged, the casting operation is carried out at the casting station.

[0028] The off-line casting process employs an off-line collection device comprising a collection container 5 and a transition bridge 10. The collection container 5 has a top-opening structure and its inner cavity is an inverted frustum-shaped cavity with a larger upper opening and a smaller lower base, preferably an inverted frustum-shaped cavity, to facilitate subsequent scrap steel demolding and prevent scrap steel from sticking. The collection container 5 is equipped with one or two pairs of lifting lugs, symmetrically distributed on both sides, to meet the requirements for supporting the tilting and dumping of scrap steel. The transition bridge 10 is a plate-like structure, mounted between the collection container 5 and the top of the ingot mold 7, and located below the ladle movement path.

[0029] 5) Figure 3 , 7 As shown in Figure 18, a flow rate control rod is used to control the flow rate of molten steel during the casting process. The flow rate control rod has the following structure: the flow rate control device is an integral rod-shaped structure, including a front horizontal section, an inclined adjustment section, and an end horizontal section; the front horizontal section is a straight rod located at the front end of the flow rate control rod; an annular protrusion is provided on the front horizontal section, which can be inserted into the hole of the rocker arm 51 of the sliding gate mechanism. The end horizontal section is a straight rod located at the rear end of the flow rate control rod, serving as an operating handle. The inclined adjustment section is a straight rod located between the front and end horizontal sections; the front and end horizontal sections are designed to be parallel, and the inclined adjustment section is inclined between the front and end horizontal sections; the angle between the inclined adjustment section and the front and end horizontal sections is an obtuse angle, preferably between 135° and 165°.

[0030] The process of using the flow rate control rod is as follows: The operator holds the horizontal end section and inserts the horizontal end section of the flow rate control rod into the rocker arm 51 of the ladle sliding nozzle. By tilting the flow rate control rod up and down, the tilt angle of the rocker arm 51 is changed, thereby driving the stroke of the lower nozzle pull rod 52 connected to the rocker arm 51. This causes the overlapping area of ​​the upper slide plate hole 17 and the lower slide plate hole 18 to change accordingly, thereby adjusting the flow cross section of the molten steel. Example

[0031] 1) Off-line collection device for coordinated off-line pouring: When molten steel is poured, the ladle outlet 35 needs to be opened to release the guide sand and steel slag 9. However, in actual production, it was found that due to the smaller tonnage of the ladle 3 used for special steel grades, the self-opening rate of the ladle outlet 35 is low. Manual oxygen blowing and burn-out are required to assist in the flow and achieve the purpose of pouring. However, during the manual flow-assisted process, the guide sand 9 mixed with molten steel, combined with the combustion aid of oxygen, severely damages the refractory material inside the pouring pipe 8, causing the steel flow 12 to disperse, deepening the secondary oxidation of the molten steel, affecting the quality of the molten steel. Furthermore, the steel slag and reactants from the guide sand 9 that fall during pouring can easily clog the pouring pipe 8, making the pouring operation impossible, or resulting in low purity inside the ingot, affecting the final ingot quality. To prevent ingot quality problems, the pouring operation adopts an off-line pouring method. After the guide sand 9 is discharged and the steel flow 12 is complete, the pouring operation is resumed at the pouring station to ensure the quality of the ingot. The external casting collection device 5 collects the molten steel flowing out during the initial stage of casting. After cooling, it is demolded and recycled, and can be used as scrap steel. It has high practical value and is worth promoting.

[0032] When using the casting method of casting outside the line, if the molten steel and slag inclusions that flow out are not treated in a centralized manner, they will affect the casting of the next heat. Therefore, the following method is adopted to assist in the normal operation of the casting process.

[0033] Technical specifications of the off-line casting collection device 5: 1.1) Main structure of collection container 5: It adopts an integral casting molding process, with a main body size of 1000mm×700mm×700mm (height×width×depth) cube structure, and the four corners adopt a large R230 rounded transition design to effectively avoid stress concentration.

[0034] 1.2) Lifting System: The collection container 5 is equipped with four cylindrical lifting lugs of φ80mm×100mm, symmetrically distributed on both sides, to meet the requirements for supporting the tipping and dumping of scrap steel. 1.3) Features of the collection container 5: The inverted platform-shaped cavity design has an upper diameter of φ500mm, a bottom diameter of φ350mm, an effective depth of 750mm, and a volume of ≈0.12m³, which meets production requirements.

[0035] 1.4) Process optimization of collection container 5: The inner bottom edge adopts R120mm flow guide rounded corner, and the inner surface is treated with Ra3.2 precision machining. The tapered design facilitates subsequent demolding of scrap steel and avoids scrap steel sticking.

[0036] 1.5) Transition Bridge 10: The support plate of Transition Bridge 10 has dimensions of 300mm (W) × 100mm (T) × 350mm (L). Its main function is to support the path of molten steel from the collection container 5 to the ingot mold 7 and prevent molten steel from splashing out.

[0037] 1.6) When in use, use the bracket 11 to support the collection container 5 so that the upper opening of the collection container 5 is not higher than the upper opening of the middle injection tube 8.

[0038] 2) Centering is performed using centering device 16 and laser level 21 in conjunction: 2.1) Structural design and functional description of centering device 16: The centering device 16 uses a high-strength galvanized steel pipe (DN15, L=2000mm) as the main rod, and achieves the integrated design of multi-functional positioning components through precision welding process, ensuring safe operating distance and accurate centering function during the pouring operation.

[0039] At one end of the main rod, a DN15 pipe with a length of 100mm is welded upward along the axial direction to serve as the upper positioning rod 14. The lower center point of the upper positioning rod 14 is defined as the centering point A of the centering device 16. During operation, the upper positioning rod 14 needs to be precisely inserted into the reserved hole 18 of the lower slide plate of the ladle sliding nozzle 13.

[0040] Using centering point A of the centering device 16 as a reference, along the axial direction of the device downwards, a DN15 pipe with a length of 150mm is welded as a lower positioning rod, with a travel distance of 100mm between the upper sliding plate hole 17 and the lower sliding plate hole 18 of the ladle sliding nozzle 13. Using the bottom center of the lower positioning rod as the positioning point, a circular plate with a diameter of 220mm is welded as a bowl-shaped cover plate 15, the size of which is consistent with the inner diameter of the bowl-shaped opening 19 on the middle injection pipe. The upper center point of the lower positioning rod is defined as centering point B. Before the molten steel pouring process, the bowl-shaped cover plate 15 will be tightly embedded in the bowl-shaped opening 19 on the middle injection pipe, achieving rapid and accurate centering of the middle injection pipe 8 through precise geometric positioning.

[0041] This centering device 16 achieves the following through the two-point collaborative positioning principle of centering point A and centering point B: primary positioning, mechanical coupling between the upper positioning rod 14 and the sliding nozzle 13 mechanism; secondary positioning, geometric constraint between the bowl cover plate 15 and the upper bowl 19 of the middle injection pipe; and dynamic calibration, with stroke compensation automatically adapting to the opening and closing displacement of the nozzle.

[0042] 2.2) During the pouring process, the ladle's outlet 35 employs a moving sliding plate mechanism for pouring. The lower sliding plate of the ladle's outlet 35 moves under the action of this mechanism, while the upper sliding plate remains stationary. This ensures that the holes 17 and 18 on the upper and lower sliding plates are aligned, achieving both molten steel flow and closure. If the ladle's outlet 35 is not accurately aligned with the central pouring pipe 8 below after the ladle is set, not only will the high-temperature molten steel erode the refractory material, carrying impurities into the ingot, but it will also cause difficulties in controlling the pouring rate, resulting in inconsistent pouring speeds. The uneven movement of the molten steel leads to inconsistent thickness across the ingot, with thicker areas of the chilled layer shrinking more, creating axial tensile stress in thinner areas. This can cause cracks in the ingot, affecting product quality.

[0043] Therefore, before the pouring operation, the sliding gate 13 of the ladle needs to be aligned with the center of the pouring pipe 8. During the alignment process, the center of the pouring pipe 8 is used as the reference line, and the sliding plate hole 17 of the ladle sliding gate 13 mechanism is vertically aligned with the pouring pipe 8. A laser alignment instrument 21 is used in conjunction with the alignment device 16 for alignment. Specifically, the upper positioning rod 14 of the alignment device 16 is inserted into the lower sliding plate hole 18 of the ladle, and the lower positioning rod is perpendicular to the direction of the bowl 19 on the pouring pipe. After turning on the laser level 21 and adjusting the instrument, the reference point emitting the cross laser 22 is aligned with the center position of the bowl 19 on the pouring pipe. Move the cursor upwards to the main rod and observe the distance to the centering point B. Keep the upper positioning rod 14 within the lower sliding plate hole 18 of the ladle. Move the ladle 3 so that the centering point B coincides with the reference point of the crosshair laser 22 cursor. Place the bowl cover plate 15 on the bowl 19 of the middle pouring pipe. At this point, the upper sliding plate hole 17 of the ladle is aligned with the center of the middle pouring pipe 8. When pouring is required, move the lower sliding plate so that the lower sliding plate hole 18 coincides with the upper sliding plate hole 17. At this point, the molten steel can flow precisely into the center of the middle pouring pipe 8, avoiding molten steel splashing, solving the problem of difficult cleaning, reducing defects such as steel ingot scale and subcutaneous bubbles, improving molten steel yield, avoiding waste, and saving costs.

[0044] 3) An argon gas protection device 30 is installed between the drain outlet 35 of the ladle and the bowl opening 36 of the injection pipe: 3.1) Technical description of the argon gas protection device 30: After adopting the above structure, the argon protection device 30 forms three core components: an argon distribution unit, a thermal protection system, and a gas flow enhancement system. It can provide all-round inert gas protection during the steel pouring process, significantly reduce the degree of steel oxidation, and improve the quality of steel.

[0045] The argon distribution unit, namely the argon blowing ring 23, is made of a high-precision seamless stainless steel ring tube (Φ300mm, 4-point diameter). It is CNC drilled to create a 1.5mm hole array with a spacing of 10mm ± 0.1mm, ensuring uniform laminar argon coverage. It is equipped with a quick-connect argon interface (including a 150mm extension tube), allowing direct connection to a high-pressure gas supply system with a pressure ≥0.5MPa, providing convenience and speed.

[0046] The thermal protection system includes a base plate 26, a thermal radiation shielding ring 25, a protective baffle ring 27, and an argon gas rectifier chamber 28.

[0047] The base plate 26 is made of high-strength steel plate with a diameter of Φ340mm and a thickness of 4mm. A Φ125mm guide hole 29 is pre-set in the center to facilitate the molten steel to pass through the argon-protected casting device 30 from the drain outlet when the ladle is started to pour.

[0048] The heat radiation shielding ring 25 is composed of a high-temperature resistant alloy inner ring with a diameter of 237 mm and a vertical height of 53 mm. It can improve the heat radiation reflection efficiency by 60% and effectively protect the argon blowing ring 23, preventing it from deforming due to heat radiation.

[0049] The argon gas rectifier chamber 28: The outer circumference 150mm high protective baffle 27 and the inner ring form the argon gas rectifier chamber 28, which optimizes airflow and enhances the protection effect.

[0050] The airflow enhancement system: The sintered filter screen adopts a multi-layer stainless steel sintered filter screen 24 with a porosity of ≥85%. This not only makes the protective layer of argon gas blown out by the argon blowing ring 23 denser, but also prevents splashed molten steel from damaging the argon blowing ring 23 and extends the service life of the equipment.

[0051] The technical advantages of the argon gas protection device 30 are: ① Ultra-low oxidation: Argon coverage ≥99.2%, greatly reducing steel oxidation; ② Resistance to thermal deformation: ensuring stable equipment operation; ③ Maintenance-free operation: The unique stainless steel sieve plate design allows for 300 continuous pours without clogging, reducing maintenance costs and improving production efficiency.

[0052] 3.2) With the continuous advancement of metallurgical technology, the oxygen and nitrogen content in molten steel before casting has been reduced to very low levels. Therefore, it is essential to strictly control the steel casting process to prevent oxygen and nitrogen absorption during casting. Currently, our unit uses argon-protected casting, which effectively reduces secondary oxidation during the steel casting process. This improves the purity of molten steel and promotes an oxidation-free casting production model. Secondary oxidation occurs when O2 from the air is continuously supplied to the molten steel. Oxygen reacts with aluminum, manganese, and silicon in the steel until these elements are depleted, resulting in inclusions that are relatively large and contain a high proportion of weak deoxidizing elements, such as inclusions containing SiO2+MnO > 60%, which can be identified as secondary oxides.

[0053] After centering is completed, the argon protection device 30 is adjusted to confirm that there is no leakage in the argon pipe, that the pressure and flow are normal, that the robotic arm and switches are flexible, and that the blowing holes of the blowing ring 23 are not blocked. After confirming that there is no blockage, the argon gun 33 fixed on the casting car 3 is slowly pushed along the slide rail support A point 31 and slide rail support B point 32 to push the argon protection device 30 to the middle between the ladle drain 35 and the middle injection pipe bowl 36. The counterweight 34 behind the argon gun 33 is lowered so that the upper surface of the protective ring 27 is in close contact with the ladle wall of the drain 35. The cover of the middle injection pipe bowl 36 is opened, and the preparation work is completed.

[0054] Before pouring, the argon purity was set to 99.8% and the pressure to 0.4 MPa. The argon control valve was opened, and the gas was piped to the argon protection device 30. The argon was then ejected from the blowing holes of the blowing ring 23, forming a protective gas layer around the molten steel flow. After pouring began, the argon was blown downwards through the blowing holes inside the argon protection device 30 at a flow rate of 80 L / min. During the later stages of pouring, the flow rate was gradually increased to 150 L / min as the pouring flow decreased.

[0055] 4) A protective slag 42 is placed inside the steel ingot mold 7 using a rotating rolling device 37.

[0056] 4.1) Structural technical description of the rotating roller device 37: Crank handle 44: As a power input component, the crank handle 44 is manually turned to provide power for the rotation of the drum 47, thereby realizing the winding and unwinding of the wire rope 40.

[0057] The drum positioning hole and bracket positioning hole 45 are mainly used to lock the drum 47 in a certain rotational position during casting, according to the process of different sized steel ingot molds 7, to prevent it from rotating accidentally. They work in conjunction with the locking pin 46 to lock the drum 47, meeting the needs of different operations for fixing the drum 47.

[0058] Locking pin 46: This pin engages with the positioning hole on the drum and the positioning hole on the bracket 45 to lock the drum 47 in place. A folding locking pin 46 can be used; this folding design reduces the space occupied by the device while ensuring the components are locked in the working position when unfolded for use.

[0059] Drum 47: This is the winding component for the wire rope 40. The operator rotates the crank 44 to achieve the orderly winding and unwinding of the wire rope 40. The dimensions (diameter, length, etc.) of the drum 47 are designed according to actual usage requirements to meet different winding amounts and working stroke requirements of the wire rope 40.

[0060] Wire rope 40: As a working traction component, it connects to the object that needs to be pulled or lifted. It features high strength, good wear resistance, and high temperature resistance, and can withstand large tensile forces, ensuring the reliability and stability of the device during operation.

[0061] Base 48: Welded to the casting car body 3, it supports the entire device and provides a foundation for the installation of other components. Base 48 has a certain weight and structural strength to ensure the stability of the device during operation and prevent shaking or displacement.

[0062] Marker rod 49: Employs segmented color-coded coating 50, with each color corresponding to a specific ingot mold cross-sectional shape and size. Simultaneously, the wire rope 40 is positioned according to the length of the protective slag 42 to be deposited based on the different sizes and shapes of ingot molds. The markings on the marker rod are the same color as those on the wire rope 40. When the colored segment of the wire rope 40 overlaps with the marking rod, the protective slag 42 has reached the designated height within the ingot mold. This provides operators with intuitive working status indicators, facilitating precise control of the device's operation and improving work accuracy and efficiency.

[0063] 4.2) During the casting process, if protective slag 42 covers the surface of the molten steel 7 in the ingot mold, it can not only prevent the O and N in the air from reacting with the alloying elements of the molten steel and reduce porosity, but also dissolve the original inclusions in the molten steel in the protective slag, thus avoiding or reducing the generation of defects on the surface of the steel ingot.

[0064] A combination of suspension and delivery methods is adopted. Precise delivery of the protective slag 42 into the ingot mold 7 is achieved through traction by a steel wire rope 40 and a high-temperature self-release mechanism. This ensures that the protective slag 42 spreads evenly during the ascent of the molten steel, effectively improving the surface quality of the ingot and reducing defects such as inclusions and porosity. Specifically, precise speed control is first achieved through a rotating roller device 37 to ensure stable transport of the protective slag 42. A φ4mm high-temperature resistant galvanized steel wire rope 40 is used to ensure stable operation in high-temperature environments. Slowly, the protective slag (2 / 3 of the amount of protective slag 42 added when using the injection molding process is usually 2.5 kg / t of steel; for a 10-ton ingot, a total of 25 kg of protective slag 42 is required, and the 2 / 3 of the protective slag 42 bound by the hemp rope 41 is 16.7 kg) is guided to the placement termination point after passing the fixed pulley 38 behind the bottom plate and the fixed pulley 39 in front of the bottom plate of the casting car 3. This ensures that the protective slag 42 enters the ingot mold 7 vertically and is suspended in the center of the ingot mold 7, and is then placed at a height of 200 mm from the bottom of the mold. When the high-temperature molten steel enters the mold from the bottom, the heat radiation inside the ingot mold 7 rapidly increases the temperature, causing the hemp rope 41 binding the protective slag 42 to carbonize and break within 3-5 seconds. At this time, the tension of the wire rope 40 drops sharply, and the operator manually rotates the crank handle 44 to use the drum 47 to retract the wire rope 40. After the hook 43 at the front end of the wire rope 40 reaches the front fixed pulley 39, the next casting operation is prepared. The protective slag 42 inside the mold quickly covers the surface of the molten steel. As the molten steel rises inside the mold, the protective slag 42 is gradually consumed. When the molten steel rises to about 1 / 3 of the ingot height, a bright ring of molten steel will be exposed. At this time, the remaining protective slag 42 should be added quickly, in small amounts, multiple times, and continuously.

[0065] After the oxidation products float to the surface of the molten steel, they are carried by the flowing molten steel to the meniscus near the die wall and accumulate there. Because the temperature of the molten steel at the meniscus is lower, while the melting points of oxides are generally higher, the accumulated oxides quickly form a solidified shell and flow between the die wall and the billet shell, where they are squeezed onto the surface of the ingot, forming inclusions and rinds. High-melting-point oxides, especially Al₂O₃, TiO₂, and Cr₂O₃, can combine to form spinels, compounds with very high melting points and hardness, making them more susceptible to rebound and compression onto the billet shell surface, forming inclusions.

[0066] For the above steel grades, without the protective slag 42 covering during the casting process, various oxides formed by the oxidation of the molten steel are more likely to enter the space between the mold wall and the billet shell, becoming inclusions and flaking. During the solidification process of the steel ingot, these inclusions and flaking will cause uneven heat transfer from the ingot to the mold wall, promoting thermal stress concentration and causing longitudinal and transverse cracks on the surface of the steel ingot. At the same time, due to the presence of inclusions on the surface of the steel ingot, they cannot be welded together during forging, resulting in surface cracks.

[0067] At this point, to prevent the surface of the molten steel from absorbing [N], if there is no protective slag 42 covering the surface of the molten steel, the {N2} in the air will dissolve to form 2[N] molten steel. Among them, [N] easily reacts with [Ti] in stainless steel to form [TiN] which floats on the surface of the molten steel. It is then carried by the molten steel to the meniscus to accumulate and form the so-called cold skin aggregate, and is rolled into the space between the mold wall and the billet shell to form a rough surface and form pores and slag inside the pores.

[0068] 5) The flow rate of molten steel is controlled by a flow rate control rod during the pouring process.

[0069] In steel casting, precise control of the molten steel flow rate is a core element in ensuring the quality of steel ingots. The casting rate not only directly affects the internal density and surface finish of the steel ingot, but is also closely related to casting safety and production efficiency.

[0070] 5.1) The crucial role of flow rate control in ingot quality: The synergistic effect of temperature and flow rate: Too low a temperature in molten steel can lead to casting difficulties, causing defects such as short ingots, surface sand inclusions, and rejoining; too high a temperature can easily cause accidents such as burn-through of the slide plate, steel run-out, and welding mold failure, and exacerbate cracks, shrinkage cavities, and compositional segregation. Appropriate control of the flow rate is the key to balancing the temperature effect.

[0071] Defect prevention: By dynamically adjusting the injection rate, problems such as skin peeling and slag roll-up caused by turbulence or flow interruption can be avoided. At the same time, the solidification process of molten steel is optimized to reduce internal porosity and segregation.

[0072] 5.2) Limitations of traditional flow rate control technology: Currently, small-tonnage steel ladles mostly rely on manual operation of the ladle's sliding gate 13, adjusting the flow rate by moving the upper sliding plate hole 17 and the lower sliding plate hole 18 to align them. This method suffers from low operational precision and response lag, making it difficult to meet the high requirements for casting stability of special steels.

[0073] 5.3) Technical advantages of using this flow rate control lever: This flow rate control lever achieves the following through optimized mechanical structure and operating logic: Lightweight operation: Shorten the operating range and maximize the elevation angle to reduce manual labor intensity; Process precision: Improve the response speed of processes such as flow initiation, flow following, and flow enhancement to ensure a stable and controllable pouring process; Improved quality and efficiency: Reduces human error, avoids defects caused by flow rate fluctuations, and shortens the pouring cycle.

[0074] in conclusion: Efficient control of molten steel flow rate is a crucial link connecting smelting and forming processes. The improved device not only solves the pain points of traditional technology but also provides a reliable guarantee for the casting of special steels and high-quality steel grades, representing an important step in the refined development of steel production.

[0075] 5.4) Technical description of the flow rate control lever: 5.4.1) Structure of the flow rate control lever: The flow rate control rod is welded from high-strength steel pipe, and its overall structure is divided into the following functional sections: Front horizontal section: As the input connection part, it precisely connects with the rocker arm 51 of the sliding gate 13 mechanism of the ladle to ensure assembly stability and transmission accuracy.

[0076] Inclined adjustment section: core flow rate control zone. Through optimized design of the elevation angle, the rocker arm 51 of the ladle sliding nozzle 13 is controlled so that the angle of the rocker arm 51 is usually adjustable from 15° to 45°. The displacement of the operating handle is amplified and converted into the precise stroke of the slide bar 52, so as to realize the alignment adjustment of the upper slide hole 17 and the lower slide hole 18, thereby controlling the flow rate of molten steel.

[0077] The horizontal end section serves as an operating handle, reducing operator fatigue.

[0078] 5.4.2) Key Technological Innovations: Stroke amplification mechanism: The tilt adjustment section, with the rocker arm 51 as the fulcrum, is designed based on the lever principle. It converts the short stroke of the operating handle into the large displacement of the sliding plate lever 52, improving the fine adjustment accuracy. It is suitable for high-requirement casting conditions (such as special steel).

[0079] Dynamic flow rate matching: Through elevation angle optimization, a smooth transition is achieved between the stages of "opening the flow - following the flow - increasing or decreasing the flow", avoiding slag entrapment or flow interruption caused by sudden changes in flow rate in traditional operations.

[0080] High-temperature resistant rigid structure: The steel pipe is made of heat-resistant alloy (such as 304 stainless steel) to ensure long-term stable operation in the high-temperature molten steel radiation environment.

[0081] 5.4.3) Working principle: Drive the slide bar 52 to move axially and adjust the overlap area of ​​the upper slide hole 17 and the lower slide hole 18, which is continuously adjustable from 0% to 100%.

[0082] 5.4.4) Technical advantages: Compatibility: It can be adapted to steel ladles of different tonnages, including 5 to 50t. Only the angle of the tilt adjustment section needs to be adjusted to match the nozzle model.

[0083] 5.4.5) Application Effects: Defect rate reduction: Sand inclusions and rejoining defects on the surface of steel ingots are reduced by more than 30%, and the occurrence rate of shrinkage cavities is reduced by 15%.

[0084] Conclusion: This flow rate control lever, through mechanical structural innovation, transforms the control of molten steel flow rate from experience-based to precise and quantifiable operation, providing reliable technical support for the production of high-quality steel grades.

[0085] In practical use, operators adjust the stroke of the ladle's sliding gate pull rod 52 by changing the elevation angle of the tilt adjustment section. This operation directly affects the relative position of the upper sliding plate hole 17 and the lower sliding plate hole 18. When the elevation angle increases, the stroke of the sliding plate pull rod 52 of the ladle's sliding gate 19 changes, and the overlapping area of ​​the upper sliding plate hole 17 and the lower sliding plate hole 18 changes accordingly, thereby adjusting the flow cross-section of the molten steel. The change in the flow cross-section directly affects the flow rate of the molten steel, thus achieving precise control of the molten steel flow rate in the ladle and meeting the specific requirements of different steelmaking process stages for molten steel flow rate.

[0086] 6) Specific operating procedures: Before the pouring operation, the ladle 3 is hoisted onto the pouring car 4 using the gantry hook 2 of the overhead crane 1. The centering device A point 14 of the centering device 16 is inserted into the lower slide plate hole 18 of the ladle's sliding gate 13. The centering device B point 15 is aligned with the centering pipe 8, ensuring it is aligned with the centering pipe gate brick 19. A laser alignment instrument 21 is then used in conjunction with the centering device 16 for alignment, ensuring the crosshairs 22 of the laser level 21 bisect both the centering device B point 15 and the center point of the centering pipe gate brick 19. If misalignment occurs, the ladle 3 is fine-tuned using the gantry hook 2 of the overhead crane 1. After alignment, holes are drilled to secure the outside of the wheels of the pouring car 4. After removing the centering device 16, the pouring car 4 is moved above the off-line pouring device 5.

[0087] After centering is completed, slowly push the argon gas protection device 30 fixed on the casting car 4 along the slide rail support A point 31 and slide rail support B point 32 to the middle of the ladle drain 35 and the middle injection pipe bowl 36. Put down the counterweight 34 behind the argon gun 33 so that the upper surface of the argon gas protection device 30 is in close contact with the ladle wall of the drain 35. Open the middle injection pipe bowl 36. The preparation work is completed.

[0088] Before casting, the protective slag 42 is slowly passed through the bottom plate of the casting car 4 and fixed pulleys 38 and 39 by the rotating roller device 37 using steel wire rope 40 and hemp rope 41, and then placed into the steel ingot mold 7. After the protective slag 42 reaches the designated position where the color of the steel wire rope 40 overlaps with the color of the marker rod 49, the locking pin 46 is inserted into the bracket positioning hole 45 and the drum positioning hole 45 to ensure that the protective slag 42 is locked in the working position. As the molten steel rises in the mold, the protective slag 42 is gradually consumed and melts the hemp rope 41.

[0089] The ladle's molten steel flow rate control device 6 is used to open the ladle's drain outlet 35, allowing the rocker arm 51 inserted into the sliding gate 13 to move the slide plate mechanism, thus vertically aligning the lower slide plate hole 18 with the upper slide plate hole 17. The diversion sand and steel slag 9 are discharged to the off-line collection device 5. After the diversion sand and steel slag 9 are discharged and the steel flow 12 is complete and does not disperse, the casting car 4 is moved and passed through the transition bridge 10 to prevent the molten steel from flowing out. The casting car 4 is driven to the drilling fixed position and returned to the casting position. The steel flow flows into the steel ingot mold 7 through the central injection pipe 8, ensuring that the steel flow 12 enters the center of the central injection pipe 8 vertically. The operator can easily control the process operations such as opening the flow, following the flow, increasing the flow, reducing the flow and filling the casting.

Claims

1. A casting method for improving the purity of steel ingots, characterized in that, The pouring method is adopted, including the following steps: 1) hoist the ladle (3) onto the pouring car (4) and align the upper sliding plate hole (17) of the ladle (3) with the middle pouring pipe (8) vertically; 2) An argon gas protection device (30) is installed between the ladle drain (35) and the inlet of the central injection pipe (36); 3) Place protective slag (42) inside the steel ingot mold (7); 4) The pouring process begins with pouring outside the line. After the drainage sand (9) is discharged and the steel flow is complete, the pouring operation is carried out at the pouring station.

2. The casting method for improving the purity of steel ingots according to claim 1, characterized in that, The following off-line collection device is used for the off-line casting in step 4): including a collection container (5) and a transition bridge (10); the collection container (5) adopts a container structure with an open top; the transition bridge (10) is a plate structure, mounted between the collection container (5) and the top of the ingot mold (7) and located below the moving path of the ladle (3).

3. The casting method for improving the purity of steel ingots according to claim 1, characterized in that: Step 1) uses a centering device and a laser level (21) for centering; the centering device (16) includes a main rod, an upper positioning rod (14), a lower positioning rod and a bowl cover plate (15); the upper positioning rod (14) is located at the upper part of the front end of the main rod, the lower positioning rod is located at the rear end of the upper positioning rod and fixed at the lower part of the main rod, and the horizontal distance between the upper positioning rod (14) and the lower positioning rod is the travel distance of the upper and lower sliding plates of the ladle sliding nozzle; the center of the bowl cover plate (15) is fixed at the bottom of the lower positioning rod, and the size of the bowl cover plate (15) is consistent with the inner diameter of the bowl (19) of the middle injection pipe.

4. The casting method for improving the purity of steel ingots according to claim 3, characterized in that, The centering process is as follows: the main rod of the centering device (16) is kept horizontal, and the upper positioning rod (14) is inserted into the lower slide plate hole (18) of the ladle; then the reference point of the cross laser (22) emitted by the laser level (21) is aligned with the center position of the bowl on the middle injection tube, and the cursor is moved up to the position of the main rod to observe the horizontal distance with the lower positioning rod; the position of the ladle (3) is moved so that the center of the lower positioning rod coincides with the reference point of the cross laser (22) cursor; finally, the bowl cover plate (15) is placed on the bowl (19) of the middle injection tube.

5. The casting method for improving the purity of steel ingots according to claim 1, characterized in that, The structure of the argon protection device (30) in step 2) is as follows: it includes a protective baffle (27), a base plate (26), a thermal radiation shielding ring (25), a sintered filter (24), and an argon blowing ring (23); the protective baffle (27) is cylindrical, and its inner diameter can accommodate the bowl mouth (36) of the injection pipe; the base plate (26) is a circular plate with a size that matches the protective baffle (27), the base plate (26) is fixed to the bottom of the protective baffle (27), and a backflow hole (29) is provided in the center position, the size of the backflow hole (29) matching the drain outlet (35) of the ladle. The heat radiation shielding ring (25) is cylindrical, with a diameter and height smaller than the protective baffle (27), and is set on the base plate (26); the sintered filter (24) is a flat ring, set between the top of the heat radiation shielding ring (25) and the protective baffle (27), thereby forming an argon rectification chamber (28) at the bottom of the sintered filter (24); the argon blowing ring (23) is a ring structure in which the argon blowing tube is coiled in the argon rectification chamber (28); the top of the argon blowing ring (23) is provided with a ring of argon blowing holes, and one end of the argon blowing ring (23) is connected to a high-pressure argon source.

6. The casting method for improving the purity of steel ingots according to claim 1, characterized in that: In step 4), the flow rate control rod (6) is used to control the flow rate of molten steel during the pouring operation. The flow rate control device is an integral rod structure, including a front horizontal section, an inclined adjustment section and an end horizontal section. The front horizontal section and the end horizontal section are designed to be parallel to each other, and the inclined adjustment section is inclined between the front horizontal section and the end horizontal section. An annular protrusion is provided at the front end of the front horizontal section, and the annular protrusion can be inserted into the hole of the rocker arm (51) of the sliding gate mechanism.

7. A casting method for improving the purity of steel ingots according to any one of claims 1-6, characterized in that: In step 3), a rotating roller device (37) is used to place protective slag (42). The rotating roller device (37) has the following structure: it includes a base (48), a bracket, a drum (47), a crank (44), and a steel wire rope (40). There are two brackets, which are fixed on both sides of the base (48). The drum (47) is rotatably connected between the two brackets. The crank (44) is set on the outside of one bracket and connected to the center of the drum (47). The steel wire rope (40) is wound on the drum (47).

8. The casting method for improving the purity of steel ingots according to claim 7, characterized in that: The rotating roller device (37) is also provided with a marking rod (49), which is connected between two supports; different color marks are used to segment paint (50) on the marking rod, and the length of the steel wire rope (40) corresponding to the color mark segment where the steel wire rope (40) extends is confirmed.

9. A casting method for improving the purity of steel ingots according to claim 7, characterized in that: The rotating roller device (37) is also provided with a locking pin (46); at least one roller positioning hole is provided on one side of the roller (47), and at least one bracket positioning hole (45) is provided on the bracket on this side, and the roller positioning hole and the bracket positioning hole (45) are located on the same circumference; the locking pin (46) can be inserted into the bracket positioning hole (45) and the roller positioning hole.

10. A casting method for improving the purity of steel ingots according to claim 7, characterized in that: The protective slag (42) is placed using the following process: the protective slag (42) is tied with a hemp rope (41) and the hemp rope (41) is connected to the end of the wire rope (40); the protective slag (42) is moved to the placement point on the upper part of the ingot mold (7) by fixing the pulley on the bottom plate of the casting car (4); the handle (44) is turned to release the wire rope (40) and the protective slag (42) is lowered into the ingot mold (7); the hemp rope (41) carbonizes and breaks under the heat radiation inside the ingot mold, and the protective slag (42) falls down and covers the surface of the molten steel; the wire rope (40) is then retrieved.

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