Control device for bottom argon blowing of continuous casting ladle rotary table and method for removing inclusions by soft blowing

Abstract

The present application relates to the technical field of continuous casting process in steel metallurgy, in particular to a continuous casting ladle rotary table bottom argon blowing control device and a soft blowing inclusion removal method, which is provided with an argon blowing automatic butt joint mechanism and an argon blowing intelligent control switching device, realizes automatic butt joint of the continuous casting ladle rotary table ladle bottom argon blowing and automatic switching of the rotary arm argon blowing intelligent control mode, uses the existing ladle bottom blowing gas permeable brick to realize small flow static soft blowing in the pouring position of the continuous casting ladle rotary table and small flow dynamic soft blowing in the pouring process, completely replaces the existing technology LF refining later stage ladle soft blowing, overcomes the bottleneck problem of long LF refining time and the restriction of steelmaking production capacity improvement, improves the inclusion removal rate of the ladle bottom blowing gas permeable brick soft blowing, and improves the molten steel quality.

Description

Technical Field

[0001] This invention relates to the field of continuous casting technology in iron and steel metallurgy, specifically to a bottom-blowing argon control device for a continuous casting ladle rotary table and a method for soft blowing to remove inclusions. Background Technology

[0002] In the existing technology, after the ladle is refined at the LF refining position, it is hoisted to the waiting position of the continuous casting ladle turntable and then transferred to the casting position for casting. The existing technology has the following problems or deficiencies: (1) The LF refining time is long, which has become a bottleneck problem restricting the improvement of steelmaking capacity; (2) The soft blowing time in the later stage of LF refining is insufficient, which affects the removal rate of inclusions.

[0003] CN111644584B discloses a bottom-blowing argon control device for a continuous casting ladle turret and a method for soft blowing to remove inclusions. This method transfers part or all of the soft blowing from the LF refining stage to the continuous casting ladle turret. The device allows for manual ventilation and soft blowing while the ladle is stationary at the pouring position. During the pouring process, an automatic soft blowing mode and an automatic plugging mode are selected. Different automatic soft blowing modes are chosen based on the different requirements for controlling inclusions in the steel. The proportion of molten steel poured in the ladle varies depending on the automatic soft blowing mode, and different types of ventilation bricks are used. Problems or shortcomings of this scheme: The gas source outlet 1# and gas source outlet 2# described in this scheme are connected to the bottom blowing permeable brick 1# and permeable brick 2# of the ladle via quick connectors, which is neither safe nor reliable, limiting its industrial application. In addition, the argon blowing time at the waiting position on the continuous casting ladle turret is 2 to 4 minutes, which is too short and seriously affects the removal rate of inclusions in the molten steel in the early stage of continuous casting, thus affecting the quality of the continuous casting billet.

[0004] CN108817337B discloses a method for argon blowing on a ladle turret in continuous casting mode, as well as the ladle turret itself. This method moves the argon blowing process from the ladle to the continuous casting turret, resolving the conflict between argon blowing time and production rhythm. However, this method has some drawbacks: the argon flow rate at the pressing position is 38–42 L / h (equivalent to 0.63–0.7 L / min), which is too low, resulting in poor inclusion removal. Furthermore, the ladle argon blowing turret lacks an automatic docking device, making manual docking unreliable and unsafe, thus hindering its widespread application.

[0005] CN101586177A discloses a method for reducing titanium inclusions in molten steel. This method reduces titanium inclusions in a specific type of cord steel by further performing bottom blowing argon on the ladle and bottom blowing argon during the ladle casting process after completing all refining processes in order to remove titanium inclusions. However, this method is not suitable for all steel types and all inclusions, thus limiting its widespread application. Summary of the Invention

[0006] The purpose of this invention is to provide a bottom-blowing argon control device for a continuous casting ladle turret and a method for removing inclusions by soft blowing. It incorporates an automatic argon blowing docking mechanism and an intelligent argon blowing control switching device, enabling automatic docking of bottom-blowing argon on the continuous casting ladle turret and automatic switching of argon blowing control on the turret arm. Utilizing existing bottom-blowing permeable bricks, it achieves small-flow static soft blowing at the waiting position and small-flow dynamic soft blowing during the pouring process at the pouring position on the continuous casting ladle turret, completely replacing the existing late-stage soft blowing technology in LF refining. This overcomes the bottleneck problem of long LF refining time and its restriction on increasing steelmaking capacity, improves the inclusion removal rate of bottom-blowing permeable brick soft blowing, and enhances the quality of molten steel.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A bottom-blowing argon control device for a continuous casting ladle turret includes a gas path control unit, a continuous casting foundation automation system, a ladle molten steel weighing system, an argon blowing intelligent control switching device, a PLC, a continuous casting ladle turret, an automatic argon blowing docking mechanism, and a ladle. The PLC is communicatively connected to the gas path control unit and the continuous casting foundation automation system, and the ladle molten steel weighing system is communicatively connected to the continuous casting foundation automation system.

[0009] The continuous casting ladle rotary table is equipped with two rotary arms;

[0010] The ladle is equipped with two bottom-blown permeable bricks.

[0011] The argon blowing automatic docking mechanism includes a lower component and an upper component. The lower component is mounted on a rotary arm and includes an inlet pipe. The upper component is mounted at the bottom of the ladle trunnion box and includes an outlet pipe. The outlet pipe is connected to the bottom blowing permeable brick of the ladle. When the ladle is seated on the rotary arm, the lower component docks with the upper component and connects the inlet pipe with the outlet pipe.

[0012] The gas control unit includes two argon gas control lines, and each of the argon gas control lines supplies argon gas to one of the gas inlet pipes on the two rotating arms through an argon blowing intelligent control switching device.

[0013] The PLC acquires the pouring position start signal of the continuous casting ladle rotary table in the continuous casting basic automation system to determine whether the rotary arm is in the waiting position or the pouring position. For the rotary arm in the waiting position, the PLC controls the gas circuit control unit to switch to quantitative control mode, that is, to provide a constant argon flow rate. For the rotary arm in the pouring position, the PLC controls the gas circuit control unit to switch to adaptive control mode, that is, according to the molten steel weighing signal of the molten steel weighing system in the ladle, the argon flow rate during the pouring process decreases linearly as the weight of the molten steel in the ladle decreases.

[0014] Furthermore, the technical solution of the present invention also includes a main gas source circuit and a gas manifold in the gas circuit control unit;

[0015] The upstream end of the main gas supply line is provided with an argon gas inlet, and the downstream end of the main gas supply line is connected to a gas manifold. The main gas supply line is provided with the following components in sequence from upstream to downstream: a first ball valve, a first pressure sensor, a pressure regulator, a first filter, a second filter, and a second pressure sensor.

[0016] The argon control pipeline includes an argon main line, an automatic branch line, a manual bypass line, and a venting branch line. The upstream end of the automatic branch line is connected to a gas manifold, and from upstream to downstream, the automatic branch line is equipped with a first automatic branch ball valve, an automatic branch solenoid valve, a metallurgical quality controller, and a second automatic branch ball valve. The upstream end of the manual bypass line is connected to a gas manifold, and from upstream to downstream, the manual bypass line is equipped with a first manual bypass ball valve, a manual regulating valve, and a second manual bypass ball valve. The downstream ends of both the automatic branch line and the manual bypass line are connected to the upstream end of the argon main line, and from upstream to downstream, the argon main line is equipped with a pressure gauge, an argon main line pressure sensor, and an argon main line ball valve. The downstream ends of both the automatic branch line and the manual bypass line are connected to the upstream end of the venting branch line, and from upstream to downstream, the venting branch line is equipped with a venting branch solenoid valve and an exhaust throttle valve.

[0017] The first pressure sensor of the main gas supply line, the second pressure sensor of the main gas supply line, the automatic branch solenoid valve, the metallurgical quality controller, the argon main gas supply line pressure sensor, and the venting branch solenoid valve are all connected to the PLC.

[0018] Each of the rotary arms is equipped with two lower components. The argon blowing intelligent control switching device has four gas supply branches. From upstream to downstream, each gas supply branch is equipped with a manual ball valve, a solenoid valve, and a filter. The solenoid valve is connected to a PLC. The four gas supply branches are connected to four air inlet pipes respectively. Each argon control pipeline is connected to two gas supply branches. The two gas supply branches connected to each argon control pipeline are connected to the air inlet pipes on two rotary arms respectively.

[0019] The technical solution of the present invention also includes a control cabinet, in which the air circuit control unit and the PLC are both installed. The control cabinet is equipped with a cooling control unit, which includes a cooling pipe. From upstream to downstream, the cooling pipe is provided with a cooling pipe ball valve, a cooling pipe pressure sensor, a cooling pipe filter, and a cooling pipe solenoid valve. The cooling pipe pressure sensor and the cooling pipe solenoid valve are both connected to the PLC. The outlet of the cooling pipe is located between the air circuit control unit and the PLC.

[0020] The technical solution of the present invention also includes an operation box, which is equipped with signal lights, a touch screen, and control buttons. The signal lights, touch screen, and control buttons are all connected to a PLC. The touch screen is used by the user to set the argon blowing time of the ladle at the waiting position and the argon blowing time of the pouring position on the continuous casting ladle rotary table, and to display the actual argon blowing time of the waiting position and the actual argon blowing time of the pouring position in real time.

[0021] Preferably, it also includes a continuous casting ladle turret control box, which is used for human-machine interaction of the continuous casting ladle turret. Both the control box and the continuous casting ladle turret control box are located in the ladle operating room and are operated by the ladle operator.

[0022] Another technical solution of the present invention is that each of the rotary arms is symmetrically provided with two saddle seats, and each of the saddle seats corresponds to an argon blowing automatic docking mechanism; the saddle seats are provided with notches;

[0023] The lower assembly also includes a pressure cap, a lower connector, a disc spring assembly, a sealing ring, a disc-shaped bracket, and a soot blowing cover plate. The pressure cap is installed in a recess by screws. The lower connector is movably disposed inside the pressure cap. The disc spring assembly is disposed between the lower connector and the saddle seat. The sealing ring is embedded in a groove at the top of the lower connector. The air inlet pipe passes through the saddle seat and connects to the lower connector. The air inlet pipe communicates with a through hole located at the center of the lower connector. The disc-shaped bracket is fixedly installed at the upper center of the lower connector. The center of the disc-shaped bracket has an air outlet. The soot blowing cover plate is movably installed in the air outlet and is used to open or close the air outlet.

[0024] The upper component also includes a base plate, an insulation plate, and an upper connector, which are arranged sequentially from top to bottom, and the vent pipe passes through the base plate, the insulation plate, and the upper connector.

[0025] During docking, under the action of the disc spring assembly, the top surface of the lower connector fits against the bottom surface of the upper connector.

[0026] Another aspect of the technical solution of the present invention is that the argon flow rate during the casting process decreases linearly as the weight of molten steel in the ladle decreases. This refers to adaptively controlling the argon flow rate according to the adaptive mode argon blowing control curve created by the initial argon flow rate setting value and the initial molten steel weight setting value, as well as the stop argon flow rate setting value and the stop molten steel weight setting value at the casting position.

[0027] The present invention also provides a method for soft blowing to remove inclusions using the above-mentioned bottom blowing argon control device for the rotary table of a continuous casting ladle.

[0028] The entire soft blowing time of the ladle in the later stage of LF refining was transferred to the continuous casting ladle rotary table, and a constant argon flow rate was used to soft blow the ladle at the pouring position for 8 to 15 minutes.

[0029] During the pouring process at the pouring position, the ladle is soft-blown for 10 to 20 minutes. Based on the weighing signal of the molten steel in the ladle's weighing system, the argon flow rate during the pouring process is linearly reduced as the weight of the molten steel in the ladle decreases.

[0030] The temperature of the steel being fed onto the turret of the continuous casting ladle is calculated using the following formula:

[0031] T = T f +T w ×k1+T p ×k2

[0032] In the above formula, T represents the loading temperature of the steel onto the turret of the continuous casting ladle, in °C; T f T represents the loading temperature of the continuous casting ladle turret in the prior art. f The value range is 1564~1579℃; T w The soft blowing time at the pouring location is in °C; k1 ranges from 0.4 to 0.5, and its unit is °C / min; T p The soft blowing time at the pouring position is in °C; the value of k2 ranges from 0.3 to 0.4, and the unit is °C / min.

[0033] Preferably, for steel grades with low inclusion control requirements, the soft blowing time during the pouring process at the pouring position is 10 minutes; for steel grades with medium inclusion control requirements, the soft blowing time during the pouring process at the pouring position is 15 minutes; and for steel grades with high inclusion control requirements, the soft blowing time during the pouring process at the pouring position is 20 minutes.

[0034] Another aspect of the technical solution of the present invention is that the argon flow rate of the ladle during soft blowing at the casting position is 30-40 NL / min; during the casting process at the casting position, the initial argon flow rate is 25-30 NL / min, and as the amount of molten steel in the ladle decreases, the argon flow rate decreases linearly to 15-20 NL / min.

[0035] Another aspect of the technical solution of this invention is to adjust the soft blowing time or argon flow rate at the pouring position of the continuous casting ladle tundish when the molten steel temperature is too high or too low.

[0036] If the temperature of the continuous casting tundish exceeds the upper limit preset value T u If the temperature is 3-5℃, extend the soft blowing time at the pouring position of the continuous casting ladle turret by 5-10 min or increase the argon flow rate by 5-10 NL / min, where T u =Liquidotherm temperature of steel grade + 28℃;

[0037] If the temperature of the continuous casting tundish is lower than the preset lower limit T dIf the temperature is 3-5℃, shorten the soft blowing time at the pouring position of the continuous casting ladle turret by 5-10 min or reduce the argon flow rate by 5-10 NL / min. Where T d = Liquidus temperature of steel grade + 15℃.

[0038] Another technical solution of the present invention is that when the bottom blow-through permeable brick of the ladle is blocked, the blow-through flow rate is set to 50-100 NL / min for blow-through.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] (1) This invention provides a bottom-blowing argon control device for a continuous casting ladle turret, which is equipped with an automatic argon blowing docking mechanism and an intelligent argon blowing control switching device. It realizes the automatic docking of bottom-blowing argon on the continuous casting ladle turret and the automatic switching of intelligent control of argon blowing on the turret arm. It breaks through the key technical bottlenecks of bottom-blowing argon pipeline docking and intelligent control switching of argon blowing on the turret arm. It solves the problem of unsafe and unreliable industrial application caused by the use of quick connectors to connect the gas source outlet 1# and gas source outlet 2# of the bottom-blowing argon control device for a continuous casting ladle turret to the gas inlet pipes of bottom-blowing permeable brick 1# and permeable brick 2# of the ladle.

[0041] (2) The existing technology of soft blowing in the later stage of LF refining is completely transferred to the continuous casting ladle turret. The existing bottom blowing permeable bricks of the ladle are used to carry out small-flow static soft blowing at the waiting position and small-flow dynamic soft blowing during the pouring process at the pouring position of the continuous casting ladle turret. This breaks through the industry problems of low inclusion removal rate and large temperature drop of molten steel caused by soft blowing of bottom blowing permeable bricks of the ladle. It also overcomes the bottleneck problem of long LF refining time and restricts the improvement of steelmaking capacity. Compared with the bottom blowing argon control device and soft blowing method for removing inclusions of continuous casting ladle turret disclosed in CN111644584B, the flow rate of static argon blowing at the waiting position and dynamic argon blowing during the pouring process at the pouring position of the continuous casting ladle turret is reduced by 40% and 50% respectively compared with the existing technology. The total oxygen content of molten steel in the crystallizer is reduced by more than 12% compared with the same period.

[0042] (3) The present invention installs the lower component of the argon blowing automatic docking mechanism in the middle of the saddle seat of the existing rotary table, which simplifies the installation process of the lower component of the argon blowing automatic docking mechanism and reduces material costs.

[0043] (4) This invention addresses the problem of excessively high or low molten steel temperature in the continuous casting tundish by adjusting the soft blowing time or argon flow rate at the pouring position of the continuous casting ladle turret. This avoids the reduction in casting speed caused by high molten steel temperature and the resulting defects in billet quality, or the problem of molten steel returning to the furnace caused by low molten steel temperature.

[0044] (5) This invention addresses the problem of blockage in bottom-blown permeable bricks in steel ladles by providing a method for blocking bottom-blown permeable bricks in steel ladles. This method solves the problems of billet quality caused by low argon permeability in the early stage of argon blowing or failure to open the bottom blown, or the problem of molten steel being returned to the furnace due to nozzle holes.

[0045] (6) The bottom blowing argon control device for continuous casting ladle rotary table provided by the present invention is equipped with a cooling control unit. When the ambient temperature inside the control cabinet is greater than 40°C, a cooling medium (such as nitrogen) is introduced into the cooling pipe to cool the environment inside the control cabinet, thereby avoiding problems such as poor stability and reduced service life of electrical control components caused by high working environment temperature.

[0046] (7) In the mathematical and physical simulation experiments of removing inclusions by static soft blowing in the ladle and dynamic soft blowing during the casting process, the inventors of this invention unexpectedly discovered that the inclusion removal rate of the existing technology is not the highest when the flow rate of static soft blowing in the ladle is controlled under the condition of slight fluctuation of the molten steel surface. After a large number of simulation studies and production tests, the inclusion removal rate is the highest when the argon flow rate of static soft blowing is maintained at 60% of the argon flow rate of slight fluctuation of the molten steel surface; the inclusion removal rate is the highest when the argon flow rate of dynamic soft blowing during the ladle casting process is maintained at 50% of the argon flow rate of slight fluctuation of the molten steel surface. Existing technologies maintain a static soft blowing argon flow rate of 50-65 NL / min to keep the molten steel surface slightly fluctuating. In contrast, the present invention achieves a static soft blowing argon flow rate of 30-40 NL / min at the pouring position on the continuous casting ladle turret, and an initial argon flow rate of 25-30 NL / min during the pouring process at the pouring position on the continuous casting ladle turret. Furthermore, the argon flow rate decreases linearly to 15-20 NL / min as the amount of molten steel in the ladle decreases. This was achieved by the inventors through extensive simulation research and production trials. CN111644584B discloses a bottom-blowing argon control device for a continuous casting ladle turret and a method for removing inclusions by soft blowing. The static argon flow rate at the waiting position and the initial flow rate of the dynamic soft blowing at the pouring position on the continuous casting ladle turret are determined by measuring the argon flow rate at which the molten steel surface in the ladle experiences slight fluctuations. CN108817337B discloses an argon blowing method and a ladle turret in continuous casting mode. The argon flow rate at the pressing position is 38–42 L / h (equivalent to 0.63–0.7 L / min), which is too low, resulting in poor inclusion removal. CN101586177A discloses a method for reducing titanium inclusions in molten steel, controlling the argon flow rate at the waiting position in the ladle to 0.3 × 10⁻⁶. -3 ~4×10 -3 Nm 3 / min.t (based on the steel output of 130t according to this invention, this is converted to 39-520 Nm) 3 The argon blowing range is too large ( / min), and the maximum argon flow rate during the casting process is 1.5 × 10⁻⁶. -3 Nm 3 / min.t, the argon flow rate variation is based on the ladle casting weight according to Y = (1.5 × 10 -3 ~3×10 -3. X)Nm 3 The decreasing / min.t formula differs from the argon flow rate setting method and setting value described in this invention. This invention reduces the flow rate of static argon blowing at the waiting position and dynamic argon blowing at the pouring position on the continuous casting ladle turret by 40% and 50% respectively compared to existing technologies. This not only improves the soft-blowing inclusion removal rate and reduces argon consumption but also reduces the temperature drop of molten steel, achieving unexpected argon blowing effects. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the control device for bottom blowing argon on the continuous casting ladle rotary table in an embodiment of the present invention;

[0048] Figure 2 For this Figure 1 Enlarged view of part A in the middle;

[0049] Figure 3 This is a schematic diagram of the gas circuit control unit in an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of the cooling control unit in an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram of the process layout of the argon blowing automatic docking mechanism in an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of the saddle seat in an embodiment of the present invention;

[0053] Figure 7 This is a schematic diagram of the lower component of the argon blowing automatic docking mechanism in the soot blowing state in an embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of the adaptive mode argon blowing control curve in an embodiment of the present invention.

[0055] The components are: 1-Gas circuit control unit, 2-Continuous casting foundation automation system, 3-Ladle molten steel weighing system, 4-Argon blowing intelligent control switching device, 5-PLC, 6-Continuous casting ladle rotary table, 7-Ladle, 8-Rotating arm, 9-Inlet pipe, 10-Outlet pipe, 11-Gas manifold, 12-First ball valve of main gas supply line, 13-First pressure sensor of main gas supply line, 14-Pressure regulator, 15-First filter of main gas supply line, 16-Second filter of main gas supply line, 17- 18-Second pressure sensor for main gas supply line; 19-First ball valve for automatic branch line; 20-Solenoid valve for automatic branch line; 21-Metallurgical quality controller; 22-Second ball valve for automatic branch line; 23-First ball valve for manual bypass line; 24-Manual regulating valve; 25-Second ball valve for manual bypass line; 26-Pressure gauge for main argon gas supply line; 27-Ball valve for main argon gas supply line; 28-Solenoid valve for venting branch line; 29-Exhaust throttle valve; 30-Manual ball valve for gas supply branch line; 31-Gas supply branch line... Solenoid valve, 32-Air supply branch filter, 33-Control cabinet, 34-Cooling control unit, 35-Cooling pipeline ball valve, 36-Cooling pipeline pressure sensor, 37-Cooling pipeline filter, 38-Cooling pipeline solenoid valve, 39-Operating box, 40-Touch screen, 41-Saddle seat, 42-Gland cover, 43-Lower connector, 44-Disc spring assembly, 45-Sealing ring, 46-Disc bracket, 47-Soot blowing cover plate, 48-Base plate, 49-Insulation plate, 50-Upper connector Connector, 51-Notch, 52-Bottom-blowing permeable brick of steel ladle, 53-Cooling settling tank, 54-Pressure relief hole, 55-Power light, 56-Alarm light, 57-Light test, 58-Station control button, 59-Start button, 60-Stop button, 61-Rotating arm selector switch, 62-Emergency stop button, 63, 64-Argon blowing flow rate setting, 65, 66-Fine adjustment increase button, 67, 68-Fine adjustment decrease button, 69, 70-Automatic button, 71, 72-Blocking button. Detailed Implementation

[0056] The present invention will be further described below with reference to the accompanying drawings:

[0057] Example 1

[0058] Figures 1 to 8 Embodiment 1 of the present invention is shown.

[0059] This embodiment provides a bottom-blowing argon control device for a continuous casting ladle turret, including a gas circuit control unit 1, a continuous casting foundation automation system 2, a ladle molten steel weighing system 3, an argon blowing intelligent control switching device 4, a PLC 5, a continuous casting ladle turret 6, an automatic argon blowing docking mechanism, a ladle 7, an operation box 39, a continuous casting ladle turret operation box, a cooling control unit 34, and a control cabinet 33.

[0060] like Figure 1As shown, the gas circuit control unit 1, PLC 5, and cooling control unit 34 are arranged from top to bottom in the control cabinet 33, which is located near the argon gas source outside the rotation radius of the continuous casting ladle rotary table 6.

[0061] The PLC5 (Programmable Logic Controller) includes a CPU, a digital processing module, an analog processing module, and a communication module. The PLC5 is communicatively connected to the gas control unit 1, the continuous casting foundation automation system 2, the operation box 39, and the cooling control unit 34. The communication module includes an Ethernet network and a network switch. The molten steel weighing system 3 in the ladle is communicatively connected to the continuous casting foundation automation system 2.

[0062] The continuous casting ladle turret 6 is equipped with two rotating arms 8, and the continuous casting ladle turret operation box is used for human-machine interaction of the continuous casting ladle turret 6.

[0063] The ladle 7 is provided with two bottom-blown permeable bricks 52.

[0064] like Figure 5 As shown, each of the rotary arms 8 is symmetrically provided with two saddle seats 41. Figure 6 As shown, a notch 15 with a width of 320mm is machined in the center of the upper part of the saddle seat 41. Six "T"-shaped holes are evenly machined on an arc with a diameter of 180mm centered on the notch 51. The upper circle has a diameter of 38mm and a height of 30mm, and the lower circle has a diameter of 22mm and a height of 50mm, for mounting the disc spring assembly 44. Four internal screw holes are evenly machined at the four corners of the notch 51, with a spacing of 210mm between adjacent internal screw holes, for fixing the pressure cap 42, specification M20-7H. A through hole with a diameter of 80mm is machined in the center of the notch 51 for mounting the air intake pipe 9.

[0065] Each of the saddle seats 41 corresponds to an argon-blown automatic docking mechanism.

[0066] Specifically, such as Figure 2As shown, the lower assembly includes an air intake pipe 9, a pressure cap 42, a lower connector 43, a disc spring assembly 44, a sealing ring 45, a disc-shaped bracket 46, and a soot blowing cover plate 47. The pressure cap 42 is installed in the recess 51 by screws. The lower connector 43 is movably disposed inside the pressure cap 42. The top surface of the lower connector 43 has a cavity with a trapezoidal longitudinal section and a frustum-shaped cross section in the center. The disc spring assembly 44 is disposed between the lower connector 43 and the saddle seat 41, providing elastic support for the lower connector 43 in the direction of gravity. The sealing ring 45 is embedded in a groove at the top of the lower connector 43. The air intake pipe 9 passes through the saddle seat 41 and connects to the lower connector 43. The air intake pipe 9 communicates with a through hole located at the center of the lower connector 43. The disc-shaped bracket 46 is fixedly installed at the upper center of the lower connector 43. The center of the disc-shaped bracket 46 is provided with an air outlet. The soot blowing cover plate 47 is an umbrella-shaped structure with a cover and a rod. The soot blowing cover plate 47 is installed in the air outlet and can be moved up and down to open or close the air outlet.

[0067] like Figure 7 As shown, when argon gas enters the inlet pipe 9, the argon gas in the inlet pipe 9 pushes the rod and cover of the dust blowing cover 47 upward, and the argon gas is blown out through the outlet hole, blowing away the dust in the cavity on the upper surface of the lower connector head, thus solving the problem of dust clogging the outlet hole. The upper component is installed at the bottom of the trunnion box of the ladle 7, as shown in the figure. Figure 2 As shown, the upper assembly includes an exhaust pipe 10, a base plate 48, an insulation plate 49, and an upper connector 50, arranged sequentially from top to bottom. The exhaust pipe 10 passes through the base plate 48, the insulation plate 49, and the upper connector 50. Two exhaust pipes 10 on each rotating arm 8 are respectively connected to two bottom-blown permeable bricks 52 located in the groove at the bottom of the ladle 7 trunnion box. The insulation plate 49 is used to reduce the temperature impact of heat transfer from the ladle 7 on the upper connector 50, preventing high-temperature deformation of the upper connector 50 and subsequent air leakage at the mating surface.

[0068] After the ladle 7 is seated on the rotating arm 8, under the action of the disc spring assembly 44, the top surface of the lower connector 43 fits against the bottom surface of the upper connector 50, and the sealing ring 45 is used to seal the mating surfaces of the upper connector 50 and the lower connector 43, so that the air inlet pipe 9 and the air outlet pipe 10 are connected.

[0069] A cooling groove 53 is provided between the top surface of the upper connector 50 and the bottom surface of the base plate 48. The cooling groove 53 is connected to the surrounding area, and gas can flow through the gap between the upper connector 50 and the base plate 48 to achieve natural cooling and reduce the working temperature of the upper connector 50 and the sealing ring 45.

[0070] The upper connector 50 and the bottom plate 48 are respectively provided with a through pressure relief hole 54 at both ends, which is used to prevent the sealing ring 45 from being pushed up by the residual high pressure argon gas in the cavity and damaged on the working surface after the argon blowing stops.

[0071] like Figure 2 As shown, the gas circuit control unit includes a main gas source line, an argon gas control line, and a gas manifold 11.

[0072] The upstream end of the main gas supply line is provided with an argon gas inlet, and the downstream end of the main gas supply line is connected to a gas manifold 11. The main gas supply line is provided with the following components in sequence from upstream to downstream: a first ball valve 12, a first pressure sensor 13, a pressure regulator 14, a first filter 15, a second filter 16, and a second pressure sensor 17.

[0073] The argon control pipeline has two sections, including a main argon line, an automatic branch line, a manual bypass line, and a venting branch line. The upstream end of the automatic branch line is connected to the gas manifold 11, and from upstream to downstream, it is equipped with a first automatic branch ball valve 18, an automatic branch solenoid valve 19, a metallurgical quality controller 20, and a second automatic branch ball valve 21. The upstream end of the manual bypass line is also connected to the gas manifold 11, and from upstream to downstream, it is equipped with a first manual bypass ball valve 22, a manual regulating valve 23, and a second manual bypass ball valve 24. The downstream ends of both the automatic branch line and the manual bypass line are connected to the upstream end of the main argon line, and from upstream to downstream, the main argon line is equipped with a pressure gauge 25, an argon line pressure sensor 26, and an argon line ball valve 27. The downstream ends of the automatic branch and the manual bypass are both connected to the upstream end of the venting branch. The venting branch is equipped with a venting branch solenoid valve 28 and an exhaust throttle valve 29 sequentially from upstream to downstream. The venting branch is used for exhausting and depressurizing after argon blowing stops on the bottom-blown permeable brick 52 of the ladle. After the ladle 7 completes pouring, exhausting, and depressurizing at the pouring position on the continuous casting ladle turret 6, it is rotated to the waiting position and the ladle 7 is lifted away.

[0074] The main gas supply line pressure sensor 13, the main gas supply line pressure sensor 17, the automatic branch solenoid valve 19, the metallurgical quality controller 20, the argon main supply line pressure sensor 26, and the venting branch solenoid valve 28 are all connected to the PLC5. The PLC5 obtains the pressure on the corresponding pipeline through each pressure sensor; the PLC5 obtains the argon flow rate on the automatic branch through the metallurgical quality controller 20, and adjusts the argon flow rate of the automatic branch through the metallurgical quality controller 20.

[0075] The argon blowing intelligent control switching device has four gas supply branches. Each gas supply branch, from upstream to downstream, is equipped with a manual ball valve 30, a solenoid valve 31, and a filter 32. The solenoid valve 30 is connected to a PLC 5. Each of the four gas supply branches is connected to one of the four inlet pipes 9. Each argon control pipeline connects to two gas supply branches, and these two gas supply branches are connected to the inlet pipes 9 on the two rotating arms 8. Each gas supply branch passes through the sealing ring and saddle seat 41 of the continuous casting ladle rotary table 6 before connecting to the corresponding inlet pipe 9. Since the two permeable bricks 52 installed on each ladle 7 may be of different types or have different argon blowing flow requirements, and the argon blowing parameters differ for different types of bottom-blown permeable bricks, designing an argon control pipeline for each of the four bottom-blown permeable bricks 52 corresponding to the two rotating arms 8 would be costly. In this embodiment, an intelligent argon blowing control switching device is used. Each argon control pipeline supplies argon to one of the inlet pipes 9 on each of the two rotating arms 8 via the intelligent argon blowing control switching device 4. That is, each argon control pipeline is individually controlled to blow argon to a specific type of steel ladle bottom permeable brick 52, greatly reducing costs. For example, when Figure 1 When the left-side rotary arm 8 is in the pouring position, one argon control pipeline supplies argon to the left ladle bottom permeable brick 11 of the left-side rotary arm 8 through the first gas supply branch from the top, and another argon control pipeline supplies argon to the right ladle bottom permeable brick 11 of the left-side rotary arm 8 through the third gas supply branch from the top. The second gas supply branch from the top and the aforementioned fourth gas supply branch are closed.

[0076] The gas control unit 1 operates in two modes: quantitative control and adaptive control. The PLC 5 acquires the pouring position start signal from the continuous casting ladle rotary table 6 in the continuous casting basic automation system 2 to determine which rotary arm is in the waiting-to-pour position or the pouring position. For the rotary arm in the waiting-to-pour position, the PLC 5 controls the gas control unit 1 to switch to quantitative control mode. Specifically, the PLC 5 sends a flow control command to the metallurgical quality controller 20 to keep the argon flow rate of the automatic branch constant. For the rotary arm in the pouring position, the PLC 5 controls the gas control unit 1 to switch to adaptive control mode. Specifically, the PLC 5 sends a flow control command to the metallurgical quality controller 20 based on the molten steel weighing signal from the ladle 7, causing the argon flow rate of the automatic branch to decrease linearly as the weight of the molten steel in the ladle 7 decreases.

[0077] like Figure 8As shown, the argon flow rate during the pouring process decreases linearly as the weight of molten steel in ladle 7 decreases. This means that the argon flow rate is adaptively controlled according to the adaptive mode argon blowing control curve created by the initial argon flow rate setting value and the initial molten steel weight setting value, as well as the stop argon flow rate setting value and the stop molten steel weight setting value.

[0078] like Figure 4 As shown, the cooling control unit 34 includes a cooling pipe. From upstream to downstream, the cooling pipe is sequentially equipped with a cooling pipe ball valve 35, a cooling pipe pressure sensor 36, a cooling pipe filter 37, and a cooling pipe solenoid valve 38. The cooling pipe pressure sensor 36 and the cooling pipe solenoid valve 38 are both connected to the PLC 5. The outlet of the cooling pipe is located between the gas control unit 1 and the PLC 5. When the ambient temperature inside the control cabinet 33 exceeds 40°C, nitrogen gas is introduced into the cooling pipe to cool the environment inside the control cabinet 33, preventing problems such as poor stability and reduced service life of electrical control components caused by high operating temperatures.

[0079] Both the control box 39 and the control box of the continuous casting ladle rotary table are located in the ladle control room and are operated by the ladle operator.

[0080] The control box 39 is equipped with signal lights, a touch screen 40, and a switch button from top to bottom. The signal lights, touch screen 40, and control buttons are all connected to the PLC 5.

[0081] The indicator lights include a power light 55 (white), an alarm light 56 ​​(red), and a light test 57 (green). When the power light 55 is lit (white), it indicates that the operating box 39 is powered normally. When the alarm light 56 ​​is lit and flashing, it indicates that there is a fault in the soft blowing system. The fault details of the soft blowing system touch screen need to be checked and the fault needs to be dealt with in time. When the light test 57 button is pressed, all the indicator lights on the operating box 39 will light up. If any light is not lit, the button indicator light and button switch need to be repaired and replaced in time.

[0082] The touch screen 40 interface includes a main page and a parameter setting page, which are used by the user to set the argon blowing time of the ladle 7 at the waiting position and the argon blowing time at the pouring position on the continuous casting ladle rotary table 6, and to display the actual argon blowing time of the waiting position and the actual argon blowing time of the pouring position in real time, making the setting, modification and viewing of the argon blowing time simpler and more intuitive.

[0083] The parameter setting page of the touch screen 40 includes manual parameter setting and automatic parameter setting. The manual parameter setting includes parameters such as gas source alarm, gas leakage alarm, blockage alarm, and manual argon blowing flow rate. The automatic parameter setting includes parameters such as upper limit of argon blowing flow rate, lower limit of flow rate, upper limit of pressure, lower limit of pressure, argon blowing flow rate for blockage, fine adjustment step size, and initial argon blowing flow rate, initial molten steel weight, stop argon blowing flow rate, and stop molten steel weight for the dynamic adaptive mode argon blowing control curve of the casting process. The parameter output is displayed on the main page, showing the quantitative control mode or adaptive control mode and its parameter setting values ​​and actual output values. The touch screen 40 also includes a memory for storing data sent by the PLC.

[0084] The switch buttons include a workstation control button 58 (green), a start button 59 (green), a stop button 60 (red), a rotary arm selector switch 61, an emergency stop button 62, and argon flow rate settings (1 / 2 / 3) 63, 64 for the two ladle bottom-blowing permeable bricks 52 respectively, fine-tuning increase buttons 65, 66, fine-tuning decrease buttons 67, 68, an automatic button 69, 70, and blockage removal buttons 71, 72. Detailed descriptions are as follows:

[0085] Workstation control button 58: Pressing this button will turn on the light and select the operating authority for this control box. The bottom blowing system can be operated and controlled from the control box. Operation is invalid before the indicator light is on. Setting up workstation control button 58 avoids start-up accidents caused by misoperation by non-operators.

[0086] Start button 59: Pressing this button puts the device into the start state (green indicator light illuminates); before starting the system, the rotary arm must be selected before starting the soft blowing system;

[0087] Stop button 60: Pressing this button will stop the device (red indicator light will illuminate);

[0088] Rotary arm selector switch 61: The two sides of the selector switch are used to select two rotary arms respectively. After switching the rotary arm selection, check whether the status indicator in the upper right corner of the touch screen 40 is synchronized with the selected arm.

[0089] Emergency stop button 62: There are two emergency stop positions for the ladle soft blowing system. One is installed on the workstation control panel, and the other is installed on the valve station door of the soft blowing system. In case of emergency, the nearest emergency stop button 62 can be pressed to stop the soft blowing system. After the fault is cleared, the emergency stop can be released by rotating the red button clockwise. The design of emergency stop button 62 avoids further escalation after an accident and improves the safety and reliability of the operation and control of the bottom blowing argon control device of the continuous casting ladle rotary table.

[0090] Argon blowing flow rate settings (1 / 2 / 3) 63, 64: Used in manual mode, the switch is turned to 1, 2, 3 to select manual argon blowing flow rate setting value 1, manual argon blowing flow rate setting value 2, and manual argon blowing flow rate setting value 3 respectively;

[0091] Fine-tuning plus buttons 65 and 66 and fine-tuning minus buttons 67 and 68: When you open the output parameter display interface of the touch screen 40 and find that the argon blowing flow output value does not match the set value, you can press the fine-tuning plus buttons 65 and 66 or the fine-tuning minus buttons 67 and 68 to adjust the current flow output value.

[0092] Automatic buttons 69 and 70: In automatic mode, the light is turned on, or after pressing this button, the light turns on and argon is blown in automatic mode.

[0093] Blow-blocking buttons 71 and 72: After pressing this button, its light will illuminate, and the bottom air-permeable brick 11 of the ladle will be blown and blocked according to the set blow-blocking argon flow rate.

[0094] All components in the pneumatic control unit are commercially available. Specifically, the ball valves can be DN20, 63bar304SSG1; the solenoid valves can be DC24V, G1 / 2MS; the supply branch filter 32 and cooling pipe filter 37 can be Y-type filters, 50μm; the main air supply line first filter 15 and main air supply line second filter 16 can be 40μm, 5MPa, and AF60-F10; the pressure sensors can be PT5403, 0-25barG1 / 4; the pressure regulator 14 can be BK201-25; the metallurgical quality controller 20 can be FLOX[on]62, IP65, with a flow rate of 200NL / min; the pressure gauges can be YT40; the manual regulating valves can be PN50; and the exhaust throttle valve 29 can be 3.0MPa G1 / 2.

[0095] All electrical control system components are purchased from the market. The PLC5 is a Siemens S7 series, PLCS7200-Smart, which includes AI, AO, DI, DO and other accessories. The touch screen 40 is a Siemens 7-inch touch screen.

[0096] The lower component and the upper component of the argon blowing automatic docking mechanism, including the disc spring assembly 44, sealing ring 45, screws, insulation plate 49, air inlet pipe 9, and air outlet pipe 10, are all purchased from the market. The disc spring assembly 44 is model CY06, the sealing ring 45 has a median diameter of 180×18, and the air inlet pipe 9 and air outlet pipe 10 are DN15. The other components are machined parts.

[0097] This embodiment also provides a method for removing inclusions using the aforementioned bottom-blowing argon control device on the rotary table of a continuous casting ladle. This method is used for casting large H-beams near-net-shape billets of steel grade Q235B using a 130t LF refining ladle. The requirement for inclusion control in the steel is low. Existing technology uses a soft-blowing time of 8 minutes in the later stages of LF refining. The selected manual parameter settings and specific explanations are as follows:

[0098] Gas source alarm (bar): 2.0 (When the inlet gas source pressure is less than this set value, it will prompt "low gas source pressure" and alarm light 56 ​​will light up).

[0099] Leakage alarm (bar): 0.1 (When the outlet pressure is less than this set value in manual mode, a "leakage fault" message will be displayed and alarm light 56 ​​will illuminate).

[0100] Blockage alarm (bar): 6.5 (When the outlet pressure in manual mode exceeds this setting, a "blockage fault" message will be displayed, and alarm light 56 ​​will illuminate).

[0101] Manual flow setting 1 (NL / min): 30, Manual flow setting 2 (NL / min): 35, Manual flow setting 3 (NL / min): 40 (corresponding to three different flow values ​​in manual mode);

[0102] The automatic parameter setting values ​​are explained in detail, and there are a total of settings:

[0103] Argon blowing flow rate limit (NL / min): 60 (maximum flow rate output in automatic mode);

[0104] Lower limit of flow rate (NL / min): 10 (minimum flow rate output in automatic mode);

[0105] Pressure limit (bar): 8 (maximum outlet pressure in automatic mode);

[0106] Lower pressure limit (bar): 2.5 (minimum outlet pressure in automatic mode);

[0107] Initial molten steel weight (t): 125 (When the molten steel weight is greater than or equal to the initial molten steel weight, argon is blown according to the initial argon blowing flow rate setting; when the molten steel weight is less than the initial molten steel weight, the argon blowing flow rate is adaptively controlled according to the adaptive mode argon blowing control curve).

[0108] Argon blowing stops when the weight of molten steel (t): 65 (Argon blowing stops when the weight of molten steel is less than or equal to the weight of molten steel to be blown).

[0109] Initial argon flow rate (NL / min): 25 (initial argon flow rate value corresponding to the initial argon weight in automatic mode);

[0110] Stop argon blowing flow rate (NL / min): 15 (stop argon blowing flow rate value corresponding to the weight of molten steel when stopping argon blowing in automatic mode);

[0111] Argon flow rate for plugging (NL / min): 60 (Argon flow rate used for plugging when the bottom-blown permeable brick is blocked and an alarm is triggered);

[0112] Fine-tuning step size (mbar): 1 (the step size value for the fine-tuning increase and decrease buttons in automatic mode).

[0113] The method for removing inclusions by soft blowing in this invention is as follows:

[0114] Transfer all existing LF refining late-stage ladle soft blowing time to the continuous casting ladle rotary table 6, and set it on the main page of the touch screen 40. Turn the argon blowing flow rate gear switch (1 / 2 / 3) 9f1 and 9f2 to 1, select the manual argon blowing flow rate setting value 1, and use this constant argon flow rate to soft blow the ladle of the to-be-cast position for 8 minutes.

[0115] During the pouring process at the ladle, soft blowing is performed for 10 minutes. This setting is configured on the main page of the touchscreen 40. Based on the molten steel weighing signal from the ladle's molten steel weighing system, the argon flow rate during pouring is linearly reduced as the weight of the molten steel in the ladle decreases. This is achieved by creating an adaptive argon blowing control curve based on the initial argon flow rate setting y1 and the initial molten steel weight setting x1, and the stop argon flow rate setting y2 and the stop molten steel weight setting x2 (see [link to relevant documentation]). Figure 8 Adaptive control of argon flow rate. For example... Figure 8 In the Cartesian coordinate system where the adaptive mode argon blowing control curve is located, the argon flow rate is the y-axis, the molten steel weight is the x-axis, and (x1,y1) and (x2,y2) are two points on the adaptive mode argon blowing control curve.

[0116] The temperature of the steel being fed onto the turret 6 of the continuous casting ladle is calculated using the following formula:

[0117] T = T f +T w ×k1+T p ×k2

[0118] In the above formula, T represents the loading temperature of the steel onto the turret of the continuous casting ladle, in °C; T f T represents the loading temperature of the continuous casting ladle turret in the prior art. f The value range is 1564~1579℃; T w The soft blowing time at the pouring location is in °C; k1 ranges from 0.4 to 0.5, and its unit is °C / min; T p The soft blowing time at the pouring position is in °C; the value of k2 ranges from 0.3 to 0.4, and the unit is °C / min.

[0119] In this embodiment, T = ((1568-1575) + (8 × 0.4) + (10 × 0.3))℃.

[0120] When the temperature of the molten steel in the continuous casting tundish is too high or too low, the soft blowing time or argon flow rate at the pouring position 6 of the continuous casting ladle turret should be adjusted.

[0121] If the temperature of the continuous casting tundish exceeds the upper limit preset value T u If the temperature is 3℃, extend the soft blowing time at the 6th pouring position of the continuous casting ladle turret by 5 minutes or increase the argon flow rate by 5 NL / min, where T u = Steel grade liquidus temperature +28℃; Modify the soft blowing time on the main page of the touch screen 40 or modify the initial argon blowing flow rate on the parameter setting liquid surface, thereby avoiding the reduction in casting speed caused by high pouring steel temperature and the resulting defects in billet quality.

[0122] If the temperature of the continuous casting tundish is lower than the preset lower limit T d If the temperature is 3℃, shorten the soft blowing time at the 6th pouring position of the continuous casting ladle turret by 5 minutes or reduce the argon flow rate by 5 NL / min, where T d = Steel grade liquidus temperature +15℃; Modify the soft blowing time on the main page of the touch screen 40 or modify the initial argon blowing flow rate on the parameter setting liquid surface, thereby avoiding the problem of molten steel returning to the furnace due to low pouring temperature in the continuous casting machine.

[0123] When the bottom ventilated brick 11 of the ladle becomes clogged, a purging operation is performed, which includes the following steps:

[0124] (1) Set the purging flow rate to 50NL / min on the liquid surface of parameter setting 40 on the touch screen;

[0125] (2) When the main page of the touch screen 40 displays the outlet pressure value of the bottom blown permeable brick 11 of the ladle, and the prompt changes from "normal" to "blockage fault", it is determined that the bottom blown permeable brick 11 of the ladle is blocked.

[0126] (3) Turn on the soft button on / off of the blow-off switch on the touch screen 40 (the background color turns green);

[0127] (4) Open the blow-blocking button 71 or 72 on the operation box 9 and start blowing and blocking the bottom air-permeable brick 11 of the ladle according to the blow-blocking flow rate setting;

[0128] (5) When the main page of the touch screen 40 displays the outlet pressure value of the bottom blown permeable brick 11 of the ladle, and the prompt changes from "blockage fault" to "normal", turn off the blow-block button 71 or 72 to complete the blow-blocking.

[0129] Example 2

[0130] This embodiment provides a method for removing inclusions by soft blowing using the bottom blowing argon control device of the continuous casting ladle rotary table described in Embodiment 1. It is used for casting large H-beams near-net-shape billets of steel grade S275JR in a 130t LF refining ladle. The requirements for controlling inclusions in the steel are moderate. The existing technology has a soft blowing time of 10 minutes in the later stage of LF refining.

[0131] The method for removing inclusions by soft blowing in this invention is as follows:

[0132] Transfer all existing LF refining late-stage ladle soft blowing time to the continuous casting ladle rotary table 6, and set it on the main page of the touch screen 40. Turn the argon blowing flow rate gear switch (1 / 2 / 3) 9f1 and 9f2 to 2, select manual argon blowing flow rate setting value 2, and use this constant argon flow rate to soft blow the ladle of the to-be-cast position for 10 minutes.

[0133] During the pouring process at the ladle, soft blowing is performed for 15 minutes. This setting is configured on the main page of the touchscreen 40. Based on the molten steel weighing signal from the ladle's molten steel weighing system, the argon flow rate during pouring decreases linearly as the weight of the molten steel in the ladle decreases. This is achieved by creating an adaptive argon blowing control curve based on the initial argon flow rate setting, the initial molten steel weight setting, and the stop argon flow rate setting, as well as the stop molten steel weight setting (see...). Figure 8 Adaptive control of argon flow rate.

[0134] The temperature of the steel being fed onto the turret 6 of the continuous casting ladle is calculated using the following formula:

[0135] T = T f +T w ×k1+T p ×k2

[0136] In the above formula, T represents the loading temperature of the steel onto the turret of the continuous casting ladle, in °C; T f T represents the loading temperature of the continuous casting ladle turret in the prior art. f The value range is 1564~1579℃; T w The soft blowing time at the pouring location is in °C; k1 ranges from 0.4 to 0.5, and its unit is °C / min; T p The soft blowing time at the pouring position is in °C; the value of k2 ranges from 0.3 to 0.4, and the unit is °C / min.

[0137] In this embodiment, T = ((1565-1572) + × (10 × 0.45) + (15 × 0.35))℃.

[0138] When the temperature of the molten steel in the continuous casting tundish is too high or too low, the soft blowing time or argon flow rate at the pouring position 6 of the continuous casting ladle turret should be adjusted.

[0139] If the temperature of the continuous casting tundish exceeds the upper limit preset value T u If the temperature is 5℃, extend the soft blowing time at the 6th pouring position of the continuous casting ladle turret by 10 minutes or increase the argon flow rate by 10 NL / min, where T u = Steel grade liquidus temperature +28℃; Modify the soft blowing time on the main page of the touch screen 40 or modify the initial argon blowing flow rate on the parameter setting liquid surface, thereby avoiding the reduction in casting speed caused by high pouring steel temperature and the resulting defects in billet quality.

[0140] If the temperature of the continuous casting tundish is lower than the preset lower limit T d If the temperature is 5℃, shorten the soft blowing time at the 6th pouring position of the continuous casting ladle turret by 10 min or reduce the argon flow rate by 10 NL / min, where T d = Steel grade liquidus temperature +15℃; Modify the soft blowing time on the main page of the touch screen 40 or modify the initial argon blowing flow rate on the parameter setting liquid surface, thereby avoiding the problem of molten steel returning to the furnace due to low pouring temperature in the continuous casting machine.

[0141] Example 3

[0142] This embodiment provides a method for removing inclusions by soft blowing using the bottom blowing argon control device of the rotunda of the continuous casting ladle described in Embodiment 1. It is used for casting large H-beams near-net-shape billets of steel grade SM490YB-1 in a 130t LF refining ladle. The steel has high requirements for inclusion control. In the existing technology, the soft blowing time in the later stage of LF refining is 12 minutes, and the continuous casting adopts stopper rod flow control and continuous casting protection pouring.

[0143] The method for removing inclusions by soft blowing in this invention is as follows:

[0144] All existing LF refining late-stage ladle soft blowing time is transferred to the continuous casting ladle rotary table 6 and set on the main page of the touch screen 40. The argon blowing flow rate gear switch (1 / 2 / 3) 9f1 and 9f2 are turned to 3. Select the manual argon blowing flow rate setting value 3 and use this constant argon flow rate to soft blow the ladle of the to-be-cast position for 12 minutes.

[0145] During the pouring process at the ladle, soft blowing is performed for 20 minutes. This setting is configured on the main page of the touchscreen 40. Based on the molten steel weighing signal from the ladle's molten steel weighing system, the argon flow rate during pouring is linearly reduced as the weight of the molten steel in the ladle decreases. This is achieved by creating an adaptive argon blowing control curve based on the initial argon flow rate setting, the initial molten steel weight setting, and the stop argon flow rate setting, as well as the stop molten steel weight setting (see...). Figure 8 Adaptive control of argon flow rate.

[0146] The temperature of the steel being fed onto the turret 6 of the continuous casting ladle is calculated using the following formula:

[0147] T = Tf +T w ×k1+T p ×k2

[0148] In the above formula, T represents the loading temperature of the steel onto the turret of the continuous casting ladle, in °C; T f T represents the loading temperature of the continuous casting ladle turret in the prior art. f The value range is 1564~1579℃; T w The soft blowing time at the pouring location is in °C; k1 ranges from 0.4 to 0.5, and its unit is °C / min; T p The soft blowing time at the pouring position is in °C; the value of k2 ranges from 0.3 to 0.4, and the unit is °C / min.

[0149] In this embodiment, T = ((1564-1579) + (12 × 0.5) + (20 × 0.4))℃.

[0150] When the bottom ventilated brick 11 of the ladle becomes clogged, a purging operation is performed, which includes the following steps:

[0151] (1) Set the purging flow rate to 100NL / min on the liquid surface of parameter setting 40 on the touch screen;

[0152] (2) When the main page of the touch screen 40 displays the outlet pressure value of the bottom blown permeable brick 11 of the ladle, and the prompt changes from "normal" to "blockage fault", it is determined that the bottom blown permeable brick 11 of the ladle is blocked.

[0153] (3) Turn on the soft button on / off of the blow-off switch on the touch screen 40 (the background color turns green);

[0154] (4) Open the blow-blocking button 71 or 72 on the operation box 9 and start blowing and blocking the bottom air-permeable brick 11 of the ladle according to the blow-blocking flow rate setting;

[0155] (5) When the main page of the touch screen 40 displays the outlet pressure value of the bottom blown permeable brick 11 of the ladle, and the prompt changes from "blockage fault" to "normal", turn off the blow-block button 71 or 72 to complete the blow-blocking.

[0156] Comparative Example 1

[0157] The bottom blowing argon control device and soft blowing method for removing inclusions of the continuous casting ladle rotary table disclosed in Example 1 of CN111644584B were adopted, and the steel grade was replaced with Q235B, a steel grade with low inclusion control requirements for the production of large H-beam near-net-shape billets in continuous casting machines.

[0158] Comparative Example 2

[0159] The bottom blowing argon control device and soft blowing method for removing inclusions of the continuous casting ladle rotary table disclosed in Example 1 of CN111644584B were adopted, and the steel grade was replaced with S275JR, a steel grade with medium inclusion control requirements for the production of large H-beam near-net-shape shaped billets in continuous casting machines.

[0160] Comparative Example 3

[0161] The bottom blowing argon control device and soft blowing method for removing inclusions of the continuous casting ladle rotary table disclosed in Example 1 of CN111644584B were adopted, and the steel grade was replaced with SM490YB-1, a steel grade with high requirements for inclusion control in the production of large H-beam near-net-shape shaped billets.

[0162] Experimental Example

[0163] The application of the technical solutions involved in Examples 1-3 and Comparative Examples 1-3 in the production of steel grades Q235B (low inclusion control requirements), S275JR (medium inclusion control requirements), and SM490YB-1 (high inclusion control requirements) in a near-net-shape billet continuous casting machine for large H-beams in a steel plant was compared. Gas samples of molten steel were taken from the crystallizer during the middle stage of continuous casting, and the total oxygen in the molten steel was detected by a nitrogen-oxygen analyzer. The comparison results are shown in Table 1 below.

[0164] Table 1

[0165]

[0166] By comparing the data in Table 1 above, the application of the bottom-blowing argon control device and soft-blowing method for removing inclusions on the continuous casting ladle turret of the present invention completely transfers the late-stage soft-blowing of LF refining ladle to the continuous casting ladle turret. Compared with the bottom-blowing argon control device and soft-blowing method for removing inclusions on the continuous casting ladle turret disclosed in CN111644584B, the late-stage soft-blowing time of LF refining ladle is reduced by 3-9 minutes, the total oxygen content in the molten steel in the crystallizer is reduced by more than 12%, and the flow rates of dynamic argon blowing during static argon blowing at the waiting position and dynamic argon blowing at the pouring position on the continuous casting ladle turret are reduced by 40% and 50% respectively.

[0167] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table, characterized in that, The bottom-blowing argon control device for the continuous casting ladle rotary table includes: Gas circuit control unit (1), continuous casting foundation automation system (2), ladle molten steel weighing system (3), argon blowing intelligent control switching device (4), PLC (5), continuous casting ladle rotary table (6), argon blowing automatic docking mechanism, ladle (7), the PLC (5) is connected to the gas circuit control unit (1) and the continuous casting foundation automation system (2) respectively, and the ladle molten steel weighing system (3) is connected to the continuous casting foundation automation system (2) in communication. The continuous casting ladle rotary table (6) is equipped with two rotary arms (8). Two bottom-blown permeable bricks (52) are provided on the ladle. The argon blowing automatic docking mechanism includes a lower component and an upper component. Each rotary arm (8) is symmetrically provided with two saddle seats (41), each saddle seat (41) corresponding to one argon blowing automatic docking mechanism. The lower component is mounted on the saddle seat (41), and the saddle seat (41) has a notch (51). The lower component includes an air inlet pipe (9), a pressure cap (42), a lower connector (43), a disc spring assembly (44), a sealing ring (45), and a disc bracket (46). 6) and soot blowing cover plate (47); the pressure cover (42) is installed in the recess (51) by screws, the lower connector (43) is movably disposed inside the pressure cover (42), the disc spring assembly (44) is disposed between the lower connector (43) and the saddle seat (41), the sealing ring (45) is embedded in the groove at the top of the lower connector (43); the air inlet pipe (9) passes through the saddle seat (41) and is connected to the lower connector (43), the air inlet pipe (9) and the lower connector are disposed in the groove at the top of the lower connector (43) (43) The central through hole is connected; the disc-shaped bracket (46) is fixedly installed at the upper center of the lower connector (43), and the center of the disc-shaped bracket (46) is provided with an air outlet. The soot blowing cover plate (47) is installed in the air outlet and is used to open or close the air outlet. The upper component is installed at the bottom of the trunnion box of the ladle (7). The upper component includes an air outlet pipe (10), a bottom plate (48), an insulation plate (49), and an upper connector (50). The bottom plate (48), the insulation plate (49), and the upper connector (50) are connected. Plate (49) and upper connector (50) are arranged sequentially from top to bottom. The air outlet pipe (10) passes through the bottom plate (48), insulation plate (49), upper connector (50) and is connected to the bottom blow permeable brick (52) of the ladle. When the ladle (7) is seated on the rotating arm (8), the lower component docks with the upper component. Under the action of the disc spring assembly (44), the top surface of the lower connector (43) is in contact with the bottom surface of the upper connector (50), and the air inlet pipe (9) is connected to the air outlet pipe (10). The gas control unit (1) includes two argon control pipelines, each of which supplies argon to one of the inlet pipes (9) on the two rotating arms (8) through an argon blowing intelligent control switching device (4); The PLC (5) acquires the pouring position start signal of the continuous casting ladle rotary table (6) in the continuous casting basic automation system (2) to determine the rotary arm in the waiting position and the rotary arm in the pouring position; for the rotary arm in the waiting position, the PLC (5) controls the gas circuit control unit (1) to switch to quantitative control mode, that is, to provide a constant argon flow rate; for the rotary arm in the pouring position, the PLC (5) controls the gas circuit control unit (1) to switch to adaptive control mode, that is, according to the molten steel weighing signal of the molten steel weighing system in the ladle (7), the argon flow rate is adaptively controlled according to the adaptive mode blowing argon control curve created by the initial argon flow rate setting value and the initial molten steel weight setting value and the stop argon flow rate setting value and the stop molten steel weight setting value of the pouring position; The method includes: The entire soft blowing time of the ladle in the later stage of LF refining was transferred to the continuous casting ladle rotary table (6), and a constant argon flow rate was used to soft blow the ladle at the casting position for 8 to 15 minutes. During the pouring process at the pouring position, the ladle is soft-blown for 10-20 minutes. Based on the steel weighing signal of the steel weighing system inside the ladle (7), the argon flow rate during the pouring process decreases linearly as the weight of the steel inside the ladle decreases. The temperature of the steel being fed onto the turret (6) of the continuous casting ladle is calculated using the following formula: T=T f +T w ×k1+T p ×k2 In the above formula, T represents the loading temperature of the steel onto the turret of the continuous casting ladle, in °C; T f T represents the loading temperature of the continuous casting ladle turret in the prior art. f The value range is 1564~1579℃; T w The soft blowing time at the pouring location is in °C; k1 ranges from 0.4 to 0.5, and its unit is °C / min; T p The soft blowing time at the pouring site is expressed in °C; the value of k2 ranges from 0.3 to 0.4, and the unit is °C / min. The argon flow rate of the soft blowing in the ladle (7) at the waiting position is 30~40NL / min; during the pouring process of the ladle (7) at the pouring position, the initial argon flow rate is 25~30NL / min, and as the amount of molten steel in the ladle (7) decreases, the argon flow rate decreases linearly to 15~20NL / min.

2. The method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table according to claim 1, characterized in that, The gas circuit control unit also includes a gas source main circuit and a gas manifold (11). The upstream end of the main gas source line is provided with an argon gas inlet, and the downstream end of the main gas source line is connected to a gas manifold (11). The main gas source line is provided with the following components in sequence from upstream to downstream: a first ball valve (12), a first pressure sensor (13), a pressure regulator (14), a first filter (15), a second filter (16), and a second pressure sensor (17). The argon control pipeline includes an argon main line, an automatic branch line, a manual bypass line, and a venting branch line. The upstream end of the automatic branch line is connected to the gas manifold (11), and the automatic branch line is provided with an automatic branch first ball valve (18), an automatic branch solenoid valve (19), a metallurgical quality controller (20), and an automatic branch second ball valve (21) in sequence from upstream to downstream. The upstream end of the manual bypass line is connected to the gas manifold (11), and the manual bypass line is provided with a manual bypass first ball valve (22), a manual bypass first ball valve (22), and a manual bypass second ball valve (21) in sequence from upstream to downstream. The regulating valve (23) and the manual bypass second ball valve (24) are provided. The downstream end of the automatic branch and the downstream end of the manual bypass are both connected to the upstream end of the argon main line. The argon main line is provided with a pressure gauge (25), an argon main line pressure sensor (26), and an argon main line ball valve (27) in sequence from the upstream end to the downstream end. The downstream end of the automatic branch and the downstream end of the manual bypass are both connected to the upstream end of the venting branch. The venting branch is provided with a venting branch solenoid valve (28) and an exhaust throttle valve (29) in sequence from the upstream end to the downstream end. The first pressure sensor (13) of the main gas source line, the second pressure sensor (17) of the main gas source line, the automatic branch solenoid valve (19), the metallurgical quality controller (20), the argon main gas line pressure sensor (26), and the venting branch solenoid valve (28) are all connected to the PLC (5). Each of the rotary arms (8) is provided with two lower components. The argon blowing intelligent control switching device is provided with four gas supply branches. The gas supply branches are provided with a gas supply branch manual ball valve (30), a gas supply branch solenoid valve (31), and a gas supply branch filter (32) from upstream to downstream. The gas supply branch solenoid valve (30) is connected to the PLC (5). The four gas supply branches are respectively connected to four air inlet pipes (9). Each argon control pipeline is connected to two gas supply branches. The two gas supply branches connected to each argon control pipeline are respectively connected to the air inlet pipes (9) on the two rotary arms (8).

3. The method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table according to claim 1, characterized in that, It also includes a control cabinet (33), in which the air circuit control unit (1) and PLC (5) are both located. The control cabinet (33) is equipped with a cooling control unit (34), which includes a cooling pipe. The cooling pipe is provided with a cooling pipe ball valve (35), a cooling pipe pressure sensor (36), a cooling pipe filter (37), and a cooling pipe solenoid valve (38) in sequence from upstream to downstream. The cooling pipe pressure sensor (36) and the cooling pipe solenoid valve (38) are both connected to the PLC (5). The outlet of the cooling pipe is located between the air circuit control unit (1) and the PLC (5).

4. The method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table according to claim 1, characterized in that, It also includes an operation box (39), which is equipped with a signal light, a touch screen (40), and control buttons. The signal light, touch screen (40), and control buttons are all connected to the PLC (5). The touch screen (40) is used by the user to set the argon blowing time of the ladle (7) at the waiting position and the argon blowing time at the pouring position on the continuous casting ladle rotary table (6), and to display the actual argon blowing time of the waiting position and the actual argon blowing time of the pouring position in real time.

5. The method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table according to claim 1, characterized in that, When the temperature of the molten steel in the continuous casting tundish is too high or too low, the soft blowing time or argon flow rate at the pouring position of the continuous casting ladle turret (6) should be adjusted: If the temperature of the continuous casting tundish exceeds the upper limit preset value T u If the temperature is 3~5℃, extend the soft blowing time of the continuous casting ladle turret (6) pouring position by 5~10 min or increase the argon flow rate by 5~10 NL / min, where T u =Liquidotherm temperature of steel grade +28℃; If the temperature of the continuous casting tundish is lower than the preset lower limit T d If the temperature is 3~5℃, shorten the soft blowing time of the continuous casting ladle turret (6) pouring position by 5~10 min or reduce the argon flow rate by 5~10 NL / min, where T d =Liquidotherm temperature of steel grade +15℃.

6. The method for removing inclusions using a bottom-blowing argon control device on a continuous casting ladle rotary table according to claim 1 or 5, characterized in that, When the bottom blow-through permeable brick (52) of the ladle is blocked, the blow-through flow rate is set to 50~100NL / min for blow-through.

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