Method for avoiding ladle slagging at low cost for continuous casting of a steel for automotive panels

Abstract

The present application relates to a kind of automobile panel steel continuous casting low-cost method to avoid ladle slag, belong to continuous casting method technical field.The technical scheme of the present application is: install the remaining molten steel weight calculation model of ladle critical slagging moment;The detection weight data of continuous casting ladle rotary table upper weighing device is compared with the sum of the remaining molten steel weight in ladle at ladle critical slagging moment and the remaining molten steel weight correction data at ladle critical slagging moment, when the detection weight data of continuous casting ladle rotary table upper weighing device is less than or equal to the sum of the remaining molten steel weight in ladle at ladle critical slagging moment and the remaining molten steel weight correction data at ladle critical slagging moment, control slide hydraulic cylinder to complete the closing of ladle slide.The beneficial effects of the present application are: without adding slag detection equipment, low cost, can effectively solve the problem of ladle molten steel slag, ensure the cleanliness of molten steel and the quality of subsequent casting blank.

Description

Technical Field

[0001] This invention relates to a low-cost method for continuous casting of steel for automotive panels, avoiding slag runoff from the ladle, and belongs to the technical field of continuous casting methods. Background Technology

[0002] Automotive panels are among the most demanding steel products. Automakers impose "zero defects" requirements on steel companies. This product is also the most technologically advanced steel product and is considered the "jewel" of automotive sheet metal products.

[0003] "Strip-like," "line-like," or "pinhole-like" inclusion defects in automotive panels are a common technical challenge faced by major steel companies in China. Among them, slag discharge from the continuous casting ladle during the production process is one of the causes of these defects. Since the steel used in automotive panels generally adopts the process route of converter-RH refining-continuous casting, the top slag of the ladle is an oxidizing slag system. If slag discharge occurs from the ladle, it will cause secondary oxidation of the molten steel, leading to non-steady-state casting problems such as stopper rod rise, SEN nozzle blockage, and liquid level fluctuation, ultimately affecting product quality.

[0004] Slag formation in molten steel ladle is a natural phenomenon caused by the Coriolis force. During the Earth's rotation, the Coriolis force causes the molten steel to converge towards the centerline of the taphole. The molten steel particles that initially flowed towards the centerline develop tangential and angular velocities, causing their trajectories to increasingly deviate radially and evolve into a rotating flow around the centerline. This leads to the formation of vortices on the surface of the molten steel layer; the height of the liquid surface at this point is generally called the critical swirl height. Influenced by these vortices, the steel-slag interface undergoes mutual motion and begins to emulsify. As the vortices expand into eddies, the slag covering the molten steel surface is entrained and carried into the tundish.

[0005] To avoid leaving residue in large bags, there are three traditional methods:

[0006] One approach is to estimate the amount of steel remaining in the ladle based on human experience. For example, some steel mills require 10 tons of steel remaining in the ladle for automotive panels, while high-end brands even require 30 tons. However, this approach lacks theoretical support and does not fully consider the impact of ladle melting and erosion, continuous casting speed, cross-section, and other factors on the timing of slag removal, resulting in a significant waste of costs.

[0007] Secondly, slag detection instruments, including electromagnetic induction and vibration induction, are used to detect the timing of slag discharge online, automatically closing the slide plate upon detection. For example, the "Prediction Method for Slag Entrainment in the Tundish of a Continuous Casting Machine Based on Slag Discharge Detection" published in Chinese Patent CN 108607968 B uses an electromagnetic induction coil to measure the slag entrainment rate; when the rate exceeds an abnormal value, slag entrainment is determined. While slag detection instruments can determine the timing of slag discharge, research shows that when the slag entrainment rate exceeds an abnormal value, slag has already been discharged from the molten steel. Therefore, this method cannot predict slag discharge in advance or completely avoid it.

[0008] Thirdly, the method of judging slag discharge in the ladle by comparing the amount of steel passed through is used. For example, Chinese patent CN 111250672 A discloses "A method for final pouring of continuous casting ladle based on comparison of steel passing through." This method calculates the theoretical amount of steel passed through the ladle with the slide gate fully open, compares the theoretical and actual amounts, and determines that when the actual amount of steel passed through is less than the theoretical amount, it indicates that vortices have begun to form in the ladle, thus determining the critical height and the corresponding weight of molten steel, ultimately achieving precise slag discharge. However, this method does not fully consider the effects of continuous casting speed, cross-section, steel density, etc., nor does it consider the influence of the weight and viscosity of slag in the ladle on slag discharge, making accurate prediction impossible.

[0009] In summary, traditional methods are inadequate in effectively addressing the slag runoff problem in molten steel ladle castings, failing to meet the precise control requirements of low-cost production environments. Therefore, considering the numerous shortcomings of traditional methods, a new approach is designed: specifically for automotive panel steel, this approach automatically prevents slag runoff in molten steel ladle castings based on changes in external continuous casting process conditions under low-cost operating conditions, ensuring steel cleanliness and subsequent billet quality. This will be of great significance to steelmaking production. Summary of the Invention

[0010] The purpose of this invention is to provide a low-cost method for avoiding slag discharge in continuous casting of automotive panel steel. Through dynamic evaluation and real-time model calculation, the method accurately identifies the remaining steel weight at the critical moment of slag discharge in the ladle. Then, by comparing the weight data actually detected by the weighing device on the ladle turret in real time, the method determines when to close the slide plate and controls its closure, thereby preventing slag discharge. This method eliminates the need for additional slag detection equipment, is low-cost, effectively solves the problem of slag discharge in the ladle, ensures the cleanliness of the molten steel and the quality of subsequent billets, and effectively addresses the aforementioned problems in the background technology.

[0011] The technical solution of this invention is: a low-cost method for continuous casting of automotive panel steel to avoid slag runoff from the ladle, comprising the following steps:

[0012] (1) Set the steel density, steel surplus control weight data and ladle age information;

[0013] (2) Calculation model for the weight of remaining molten steel at the critical moment of slag removal in the ladle;

[0014] (3) After the continuous casting production begins, external process data is collected in real time and model calculations are performed;

[0015] (4) When a new ladle of molten steel begins to be poured on the ladle swirl table of the continuous casting machine, update the current ladle slag setting weight, slag kinetic viscosity, ladle empty ladle setting weight and ladle cover setting weight to obtain the corrected data of the remaining molten steel weight at the current critical slag discharge time of the ladle.

[0016] (5) Real-time data on casting speed of continuous casting machine, width and thickness of billet at crystallizer outlet are collected and transmitted to the calculation model of remaining molten steel weight at critical slag discharge time of ladle. Combined with ladle age results, the weight of remaining molten steel in ladle at critical slag discharge time of ladle is calculated.

[0017] (6) Real-time acquisition of the detection weight data of the weighing device on the trolley of the continuous casting ladle, and comparison of the data with the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight of the remaining molten steel at the critical slag discharge moment. When the detection weight data of the weighing device on the trolley of the continuous casting ladle is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight of the remaining molten steel at the critical slag discharge moment, control the slide plate hydraulic cylinder to close the ladle slide plate, thereby preventing the slag in the ladle from being carried into the tundish.

[0018] (7) After the continuous casting production is completed, the model calculation and slide control of the ladle slag discharge are ended. When the new casting begins, the operations of steps (3) to (6) are repeated.

[0019] In step (2), the calculation model for the remaining molten steel weight at the critical slag discharge moment of the ladle is as follows:

[0020] m laststeel =0.3564πρ(0.000191667wL) τ ν τ ρ+0.0796){[a(0.000191667wL τ ν τ ρ+0.0796)+(r+nb)] 2 +[a(0.000191667wL τ ν τ ρ+0.0796)+(r+nb)](r+nb)+(r+nb) 2}·μ 0.0298

[0021] Where: m laststeel—The weight of the remaining molten steel in the ladle at the critical moment of slag discharge, in tons;

[0022] w—thickness at the crystallizer outlet, in meters;

[0023] L τ — Width of the crystallizer outlet at the current moment, in meters;

[0024] v τ —Current casting speed of the continuous casting machine, m / min;

[0025] ρ — Density of molten steel, ton / m³ 3 It is usually set at 7 tons / m 3 ;

[0026] n — the age of the large bag;

[0027] b — Erosion rate of the refractory material in the bulk pack wall, m / pack;

[0028] r—Inner diameter of the bottom of the large bag, in mm;

[0029] π — Pi (the mathematical constant of a circle).

[0030] μ — kinetic viscosity of steel slag, Pa·s;

[0031] a — a constant for calculation, where:

[0032]

[0033] Where: R—radius of the large bag along its inner lining, in meters;

[0034] H – The vertical height from the lining of the large bag to the bottom of the bag, in meters.

[0035] In step (4), the corrected data m' for the remaining molten steel weight at the critical slag discharge point of the ladle is...

[0036] m′=m0+m slag +m ladle +m cover

[0037] Where: m'——corrected weight of remaining molten steel at critical slag discharge in ladle, ton;

[0038] m0 — Excess weight of molten steel, usually 1 to 2 tons;

[0039] m slag —The weight of the steel slag inside the bulk bag is set in tons;

[0040] m ladle —Set the weight of the empty large package in tons;

[0041] mcover —The weight of the large bag lid is set in tons.

[0042] In step (6), the measured weight data from the weighing device on the ladle turret is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight data of the remaining molten steel at the critical slag discharge moment, i.e.

[0043] m weight ≤m laststeel +m′

[0044] Where: m weigh —Weight data measured by the weighing device on the rotary table of the continuous casting ladle, in tons;

[0045] m′=m0+m slag +m ladle +m cover

[0046] Where: m'——corrected weight of remaining molten steel at critical slag discharge in ladle, ton;

[0047] m0 — The excess weight of molten steel required, usually 1 to 2 tons;

[0048] m slag —The weight of the steel slag inside the bulk bag is set in tons;

[0049] m ladle —Set the weight of the empty large package in tons;

[0050] m cover —The weight of the large bag lid is set in tons.

[0051] The beneficial effects of this invention are: by dynamic evaluation and real-time model calculation, the weight of the remaining steel in the molten steel at the critical slag discharge moment of the ladle can be accurately identified. Then, by comparing the weight data actually detected by the weighing device on the ladle turret in real time, the timing for closing the slide plate can be determined, and the closing of the ladle slide plate can be controlled, thereby avoiding the occurrence of slag discharge in the molten steel. There is no need to add slag discharge detection equipment, which is low-cost and can effectively solve the problem of slag discharge in the ladle, ensuring the cleanliness of the molten steel and the quality of the subsequent billet casting. Detailed Implementation

[0052] To make the purpose, technical solution, and advantages of the invention's embodiments clearer, the technical solution of the invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only a small part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the protection scope of the invention.

[0053] A low-cost method for continuous casting of automotive panel steel to avoid slag runoff from the ladle includes the following steps:

[0054] (1) Set the steel density, steel surplus control weight data and ladle age information;

[0055] (2) Calculation model for the weight of remaining molten steel at the critical moment of slag removal in the ladle;

[0056] (3) After the continuous casting production begins, external process data is collected in real time and model calculations are performed;

[0057] (4) When a new ladle of molten steel begins to be poured on the ladle swirl table of the continuous casting machine, update the current ladle slag setting weight, slag kinetic viscosity, ladle empty ladle setting weight and ladle cover setting weight to obtain the corrected data of the remaining molten steel weight at the current critical slag discharge time of the ladle.

[0058] (5) Real-time data on casting speed of continuous casting machine, width and thickness of billet at crystallizer outlet are collected and transmitted to the calculation model of remaining molten steel weight at critical slag discharge time of ladle. Combined with ladle age results, the weight of remaining molten steel in ladle at critical slag discharge time of ladle is calculated.

[0059] (6) Real-time acquisition of the detection weight data of the weighing device on the trolley of the continuous casting ladle, and comparison of the data with the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight of the remaining molten steel at the critical slag discharge moment. When the detection weight data of the weighing device on the trolley of the continuous casting ladle is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight of the remaining molten steel at the critical slag discharge moment, control the slide plate hydraulic cylinder to close the ladle slide plate, thereby preventing the slag in the ladle from being carried into the tundish.

[0060] (7) After the continuous casting production is completed, the model calculation and slide control of the ladle slag discharge are ended. When the new casting begins, the operations of steps (3) to (6) are repeated.

[0061] In step (2), the calculation model for the remaining molten steel weight at the critical slag discharge moment of the ladle is as follows:

[0062] m laststeel =0.3564πρ(0.000191667wL) τ ν τ ρ+0.0796){[a(0.000191667wL τ ν τ ρ+0.0796)+(r+nb)] 2 +[a(0.000191667wL τ ν τρ+0.0796)+(r+nb)](r+nb)+(r+nb) 2}·μ 0.0298

[0063] Where: m laststeel —The weight of the remaining molten steel in the ladle at the critical moment of slag discharge, in tons;

[0064] w—thickness at the crystallizer outlet, in meters;

[0065] L τ — Width of the crystallizer outlet at the current moment, in meters;

[0066] v τ —Current continuous casting machine speed, m / min;

[0067] ρ — Density of molten steel, ton / m³ 3 It is usually set at 7 tons / m 3 ;

[0068] n — the age of the large bag;

[0069] b—Erosion rate of the refractory material in the bulk pack wall, m / pack;

[0070] r—Inner diameter of the bottom of the large bag, in mm;

[0071] π — Pi (the mathematical constant of a circle).

[0072] μ — kinetic viscosity of steel slag, Pa·s;

[0073] a — a constant for calculation, where:

[0074]

[0075] Where: R—radius of the large bag along its inner lining, in meters;

[0076] H – The vertical height (m) from the bottom edge of the large bag to the lining.

[0077] In step (4), the corrected data m' for the remaining molten steel weight at the critical slag discharge point of the ladle is...

[0078] m′=m0+m slag +m ladle +m cover

[0079] Where: m'——corrected weight of remaining molten steel at critical slag discharge in ladle, ton;

[0080] m0 — Excess weight of molten steel, usually 1 to 2 tons;

[0081] m slag—The weight of the steel slag inside the bulk bag is set in tons;

[0082] m ladle —Set the weight of the empty large package in tons;

[0083] m cover —The weight of the large bag lid is set in tons.

[0084] In step (6), the measured weight data from the weighing device on the ladle turret is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge moment and the corrected weight data of the remaining molten steel at the critical slag discharge moment, i.e.

[0085] m weight ≤m laststeel +m′

[0086] Where: m weigh —Weight data measured by the weighing device on the rotary table of the continuous casting ladle, in tons;

[0087] m′=m0+m slag +m ladle +m cover

[0088] Where: m'——corrected weight of remaining molten steel at critical slag discharge in ladle, ton;

[0089] m0 — The excess weight of molten steel required, usually 1 to 2 tons;

[0090] m slag —The weight of the steel slag inside the bulk bag is set in tons;

[0091] m ladle —Set the weight of the empty large package in tons;

[0092] m cover —The weight of the large bag lid is set in tons.

[0093] In practical applications, this invention utilizes existing equipment at the continuous casting site. Without using electromagnetic or vibratory slag detection equipment, it achieves accurate identification of the remaining steel weight at the critical slag discharge moment in the ladle through dynamic evaluation and real-time model calculation of continuous casting speed, crystallizer outlet width and thickness, molten steel density, ladle age, ladle slag setting weight, slag kinetic viscosity, ladle setting weight, and ladle cover setting weight factor. (The "critical slag discharge moment" refers to the moment when slag is about to be discharged, but before it has been discharged.) After accurately identifying this remaining steel weight, the invention further determines the timing for closing the slide plate by comparing it in real-time with the weight data actually detected by the weighing device on the ladle turret. Then, a signal is sent to the PLC controlling the ladle slide plate to close it, thereby preventing slag discharge and effectively improving the cleanliness of the molten steel, ensuring the quality of the cast billet, and effectively solving the aforementioned problems in the background technology.

[0094] When the machine performs the above-mentioned operations, it first needs to communicate directly with the PLC at the continuous casting site via the Modbus protocol. Then, it collects real-time data from the PLC on the continuous casting speed, crystallizer outlet width and thickness, and weighing results from the weighing device on the ladle turret, and transmits this data, along with other manually entered data, to the model for calculations. Additionally, it sends signals via the Modbus protocol to the PLC controlling the ladle slide, thereby controlling the closing of the ladle slide.

[0095] The relevant models involved in this invention primarily utilize numerical simulation technology to calculate the critical slag discharge height of molten steel in a ladle under different process conditions. This yields the weight of molten steel in the ladle at the critical slag discharge point under various process conditions. Then, through multiple linear regression, a calculation model for the weight of molten steel in the ladle at the critical slag discharge point is obtained. Following this model, a reasonable judgment is made regarding slag discharge, and based on the judgment result, a signal is sent to the PLC controlling the ladle slide to close the slide and prevent slag discharge.

[0096] The sliding plate typically takes 4 seconds to close completely after responding to a PLC signal. To avoid slag dripping during the sliding plate closing phase, a reasonable approach is to adjust the critical slag dripping moment back by 4 seconds based on slag dripping simulation calculations. The weight of molten steel in the ladle at this critical moment is then used as the slag dripping weight at that moment. Combined with relevant process conditions, a corresponding model is developed to ensure that slag dripping does not occur throughout the entire process, from the model sending the sliding plate closing command to the sliding plate receiving the signal to the complete sliding plate closure.

[0097] The following are five examples related to the content of the filed invention patents:

[0098] Case 1:

[0099] Step 1: Before the next continuous casting production, the continuous casting site operators measure the molten steel density to 7 tons / m³. 3 The information of 1 ton of surplus molten steel is input into the computer, and the computer transmits this data to the remaining molten steel weight calculation model at the critical slag discharge moment of the ladle.

[0100] Step 2: Once continuous casting production begins, the operator clicks the "Start Ladle Critical Slag Detection" button on the computer. The computer then begins to collect peripheral process data in real time and performs model calculations.

[0101] Step 3: When the operator observes a new ladle of molten steel being poured on the ladle turret of the continuous casting machine, the following settings are updated in the computer: slag weight of 3 tons, slag kinetic viscosity of 0.1 Pa·s, empty ladle weight of 130 tons, and ladle cover weight of 10 tons. The computer will then obtain the corrected data m' for the remaining molten steel weight at the critical slag discharge point, i.e.:

[0102] m'=1ton+3ton+130ton+10ton=144ton

[0103] Step 4: The computer collects data on the casting speed of the continuous casting machine and the width and thickness of the billet at the crystallizer outlet in real time via the Modbus protocol, and transmits this data to the remaining steel weight calculation model at the critical slag discharge moment in the ladle. The remaining steel weight (m) in the ladle at the critical slag discharge moment is then calculated. laststeel

[0104] When the computer collects the casting speed of the continuous casting machine as 1.1 m / min and the cross-sectional dimensions of the crystallizer as 1800 mm × 247 mm, the computer calculates the current steel flow rate as 7.5 ton / min. Combined with the fact that the ladle age at this time is 0 ladles, that is, the first application after the ladle hot repair, the calculated critical slag weight of the molten steel is 9 tons.

[0105] Step 5: The computer collects the measured weight data from the weighing device on the continuous casting ladle turret in real time via the Modbus protocol, and compares this data with the sum of the remaining molten steel weight in the ladle at the critical slag discharge moment (9 tons) and the corrected data of the remaining molten steel weight at the critical slag discharge moment (144 tons).

[0106] When the weighing device on the continuous casting ladle turret detects that the current weight of the ladle is 153 tons, which is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge point and the corrected weight of the remaining molten steel at the critical slag discharge point, the computer sends a command to the PLC controlling the opening and closing of the ladle slide. Upon receiving the command, the PLC controls the slide hydraulic cylinder to close the ladle slide, thus preventing slag from being carried into the tundish.

[0107] Step 6: After continuous casting production is completed, the on-site operator clicks the "End Ladle Critical Slag Discharge Detection" button on the computer. At this time, the computer will end the ladle slag discharge model calculation and slide control. When a new casting cycle begins, steps 2 to 5 will be executed again.

[0108] Case 2:

[0109] Step 1: Before the next continuous casting production, the continuous casting site operators measure the molten steel density to 7 tons / m³. 3 The information of the surplus molten steel weight of 2 tons is input into the computer, and the computer transmits this data to the remaining molten steel weight calculation model at the critical slag discharge moment of the ladle.

[0110] Step 2: Once continuous casting production begins, the operator clicks the "Start Ladle Critical Slag Detection" button on the computer. The computer then begins to collect peripheral process data in real time and performs model calculations.

[0111] Step 3: When the operator observes a new ladle of molten steel being poured on the ladle turret of the continuous casting machine, the following settings are updated in the computer: slag weight of 3 tons, slag kinetic viscosity of 0.08 Pa·s, empty ladle weight of 124 tons, and ladle cover weight of 10 tons. The computer will then obtain the corrected data m' for the remaining molten steel weight at the critical slag discharge point, i.e.:

[0112] m'=2ton+3ton+124ton+10ton=139ton

[0113] Step 4: The computer collects data on the casting speed of the continuous casting machine and the width and thickness of the billet at the crystallizer outlet in real time via the Modbus protocol, and transmits this data to the remaining steel weight calculation model at the critical slag discharge moment in the ladle. The remaining steel weight (m) in the ladle at the critical slag discharge moment is then calculated. laststeel

[0114] When the computer collects the casting speed of the continuous casting machine as 1.4 m / min and the cross-sectional dimensions of the crystallizer as 1500 mm × 247 mm, the computer calculates the current steel flow rate as 7 tons / min. Combined with the current ladle age of 10 ladles, the calculated critical slag weight of the molten steel is 8 tons.

[0115] Step 5: The computer collects the measured weight data from the weighing device on the continuous casting ladle turret in real time via the Modbus protocol, and compares this data with the sum of the remaining molten steel weight in the ladle at the critical slag discharge moment (8 tons) and the corrected data of the remaining molten steel weight at the critical slag discharge moment (139 tons).

[0116] When the weighing device on the continuous casting ladle turret detects a current ladle weight of 146.5 tons, which is less than or equal to the sum of the remaining molten steel weight at the critical slag discharge point and the corrected weight of the remaining molten steel at the critical slag discharge point, the computer sends a command to the PLC controlling the opening and closing of the ladle slide. Upon receiving the command, the PLC controls the slide hydraulic cylinder to close the ladle slide, thereby preventing slag from being carried into the tundish.

[0117] Step 6: After continuous casting production is completed, the on-site operator clicks the "End Ladle Critical Slag Discharge Detection" button on the computer. At this time, the computer will end the ladle slag discharge model calculation and slide control. When a new casting cycle begins, steps 2 to 5 will be executed again.

[0118] Case 3:

[0119] Step 1: Before the next continuous casting production, the continuous casting site operators measure the molten steel density to 7 tons / m³. 3 The information of 1 ton of surplus molten steel is input into the computer, and the computer transmits this data to the remaining molten steel weight calculation model at the critical slag discharge moment of the ladle.

[0120] Step 2: Once continuous casting production begins, the operator clicks the "Start Ladle Critical Slag Detection" button on the computer. The computer then begins to collect peripheral process data in real time and performs model calculations.

[0121] Step 3: When the operator observes a new ladle of molten steel being poured on the ladle turret of the continuous casting machine, the following settings are updated in the computer: slag weight (4 tons), slag kinetic viscosity (0.15 Pa·s), empty ladle weight (123 tons), and ladle cover weight (15 tons). The computer will then obtain the corrected data m' for the remaining molten steel weight at the critical slag discharge point, i.e.:

[0122] m'=1ton+4ton+123ton+15ton=143ton

[0123] Step 4: The computer collects data on the casting speed of the continuous casting machine and the width and thickness of the billet at the crystallizer outlet in real time via the Modbus protocol, and transmits this data to the remaining steel weight calculation model at the critical slag discharge moment in the ladle. The remaining steel weight (m) in the ladle at the critical slag discharge moment is then calculated. laststeel .

[0124] When the computer collects data showing that the continuous casting machine's casting speed is 1.3 m / min and the crystallizer cross-section is 1600 mm × 247 mm, it calculates the current steel flow rate as 7.2 ton / min. Combined with the current ladle age of 100 ladles, the calculated critical slag weight for molten steel is 9.3 tons.

[0125] Step 5: The computer collects the measured weight data from the weighing device on the ladle turret in real time via the Modbus protocol, and compares this data with the sum of the remaining molten steel weight in the ladle at the critical slag discharge moment (9.3 tons) and the corrected data of the remaining molten steel weight at the critical slag discharge moment (143 tons).

[0126] When the weighing device on the continuous casting ladle turret detects a current ladle weight of 152.3 tons, which is less than or equal to the sum of the remaining molten steel weight at the critical slag discharge point and the corrected weight of the remaining molten steel at the critical slag discharge point, the computer sends a command to the PLC controlling the opening and closing of the ladle slide. Upon receiving the command, the PLC controls the slide hydraulic cylinder to close the ladle slide, thus preventing slag from being carried into the tundish.

[0127] Step 6: After continuous casting production is completed, the on-site operator clicks the "End Ladle Critical Slag Discharge Detection" button on the computer. At this time, the computer will end the ladle slag discharge model calculation and slide control. When a new casting cycle begins, steps 2 to 5 will be executed again.

[0128] Case 4:

[0129] Step 1: Before the next continuous casting production, the continuous casting site operators measure the molten steel density to 7 tons / m³. 3 The information of 1 ton of surplus molten steel is input into the computer, and the computer transmits this data to the remaining molten steel weight calculation model at the critical slag discharge moment of the ladle.

[0130] Step 2: Once continuous casting production begins, the operator clicks the "Start Ladle Critical Slag Detection" button on the computer. The computer then begins to collect peripheral process data in real time and performs model calculations.

[0131] Step 3: When the operator observes a new ladle of molten steel being poured on the ladle turret of the continuous casting machine, the following settings are updated in the computer: slag weight of 3 tons, slag kinetic viscosity of 0.1 Pa·s, empty ladle weight of 127 tons, and ladle cover weight of 10 tons. The computer will then obtain the corrected data m' for the remaining molten steel weight at the critical slag discharge point, i.e.:

[0132] m'=1ton+3ton+127ton+10ton=141ton

[0133] Step 4: The computer collects data on the casting speed of the continuous casting machine and the width and thickness of the billet at the crystallizer outlet in real time via the Modbus protocol, and transmits this data to the remaining steel weight calculation model at the critical slag discharge moment in the ladle. The remaining steel weight (m) in the ladle at the critical slag discharge moment is then calculated. laststeel .

[0134] When the computer collects the casting speed of the continuous casting machine as 1.4 m / min and the cross-sectional dimensions of the crystallizer as 1500 mm × 247 mm, the computer calculates the current steel flow rate as 7.3 ton / min. Combined with the current ladle age of 200 ladles, the calculated critical slag weight of the molten steel is 9.7 tons.

[0135] Step 5: The computer collects the measured weight data from the weighing device on the continuous casting ladle turret in real time via the Modbus protocol, and compares this data with the sum of the remaining molten steel weight in the ladle at the critical slag discharge moment (9.7 tons) and the corrected data of the remaining molten steel weight at the critical slag discharge moment (143 tons).

[0136] When the weighing device on the continuous casting ladle turret detects a current ladle weight of 152.6 tons, which is less than or equal to the sum of the remaining molten steel weight at the critical slag discharge point and the corrected weight of the remaining molten steel at the critical slag discharge point, the computer sends a command to the PLC controlling the opening and closing of the ladle slide. Upon receiving the command, the PLC controls the slide hydraulic cylinder to close the ladle slide, thus preventing slag from being carried into the tundish.

[0137] Step 6: After continuous casting production is completed, the on-site operator clicks the "End Ladle Critical Slag Discharge Detection" button on the computer. At this time, the computer will end the ladle slag discharge model calculation and slide control. When a new casting cycle begins, steps 2 to 5 will be executed again.

[0138] Case 5:

[0139] Step 1: Before the next continuous casting production, the continuous casting site operators measure the molten steel density to 7 tons / m³. 3 The information of the surplus molten steel weight of 2 tons is input into the computer, and the computer transmits this data to the remaining molten steel weight calculation model at the critical slag discharge moment of the ladle.

[0140] Step 2: Once continuous casting production begins, the operator clicks the "Start Ladle Critical Slag Detection" button on the computer. The computer then begins to collect peripheral process data in real time and performs model calculations.

[0141] Step 3: When the operator observes a new ladle of molten steel being poured on the ladle turret of the continuous casting machine, the following settings are updated in the computer: slag weight of 3 tons, slag kinetic viscosity of 0.1 Pa·s, empty ladle weight of 125 tons, and ladle cover weight of 15 tons. The computer will then obtain the corrected data m' for the remaining molten steel weight at the critical slag discharge point, i.e.:

[0142] m'=2ton+3ton+125ton+15ton=145ton

[0143] Step 4: The computer collects data on the casting speed of the continuous casting machine and the width and thickness of the billet at the crystallizer outlet in real time via the Modbus protocol, and transmits this data to the remaining steel weight calculation model at the critical slag discharge moment in the ladle. The remaining steel weight (m) in the ladle at the critical slag discharge moment is then calculated. laststeel .

[0144] When the computer collects the casting speed of the continuous casting machine as 1.35 m / min and the cross-sectional dimensions of the crystallizer as 1700 mm × 247 mm, the computer calculates the current steel flow rate as 8 tons / min. Combined with the current ladle age of 150 ladles, the calculated critical slag weight of the molten steel is 9.9 tons.

[0145] Step 5: The computer collects the measured weight data from the weighing device on the continuous casting ladle turret in real time via the Modbus protocol, and compares this data with the sum of the remaining molten steel weight in the ladle at the critical slag discharge moment (9.9 tons) and the corrected data of the remaining molten steel weight at the critical slag discharge moment (145 tons).

[0146] When the weighing device on the continuous casting ladle turret detects a current ladle weight of 154.8 tons, which is less than or equal to the sum of the remaining molten steel weight at the critical slag discharge point and the corrected weight of the remaining molten steel at the critical slag discharge point, the computer sends a command to the PLC controlling the opening and closing of the ladle slide. Upon receiving the command, the PLC controls the slide hydraulic cylinder to close the ladle slide, thus preventing slag from being carried into the tundish.

[0147] Step 6: After continuous casting production is completed, the on-site operator clicks the "End Ladle Critical Slag Discharge Detection" button on the computer. At this time, the computer will end the ladle slag discharge model calculation and slide control. When a new casting cycle begins, steps 2 to 5 will be executed again.

Claims

1. A low-cost method for continuous casting of automotive panel steel to avoid slag runoff from the ladle, characterized in that... Includes the following steps: (1) Set the data on molten steel density, excess molten steel control weight, and ladle age; (2) Calculation model for the remaining molten steel weight at the critical slag discharge moment of the ladle; The calculation model for the remaining molten steel weight at the critical slag discharge moment of the ladle is as follows: Where: m laststeel —The weight of the remaining molten steel in the ladle at the critical moment of slag discharge, in tons; w—thickness at the crystallizer outlet, in meters; L τ — Width of the crystallizer outlet at the current moment, in meters; v τ —Current casting speed of the continuous casting machine, m / min; ρ — Density of molten steel, ton / m³ 3 Set to 7 tons / m 3 ; n — the age of the large bag; b — Erosion rate of the refractory material in the bulk pack wall, m / pack; r—Inner diameter of the bottom of the large bag, in mm; π — Pi (the mathematical constant of a circle). μ — kinetic viscosity of steel slag, Pa·s; a — a constant for calculation, where: ， Where: R—radius of the large bag along its inner lining, in meters; H – Vertical height from the bottom of the bag to the lining, in meters; (3) After the continuous casting production begins, external process data are collected in real time and model calculations are performed; (4) When a new ladle of molten steel begins to be poured on the ladle turret of the continuous casting machine, update the current ladle slag setting weight, slag kinetic viscosity, ladle empty ladle setting weight and ladle cover setting weight to obtain the corrected data of the remaining molten steel weight at the current critical slag discharge time of the ladle. (5) Real-time data on casting speed of continuous casting machine, width and thickness of billet at crystallizer outlet are collected and transmitted to the calculation model of remaining molten steel weight at critical slag discharge time of ladle. Combined with ladle age results, the weight of remaining molten steel in ladle at critical slag discharge time of ladle is calculated. (6) Real-time acquisition of the detection weight data of the weighing device on the trolley of the continuous casting ladle, and comparison of the data with the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge time and the corrected data of the weight of the remaining molten steel at the critical slag discharge time. When the detection weight data of the weighing device on the trolley of the continuous casting ladle is less than or equal to the sum of the weight of the remaining molten steel in the ladle at the critical slag discharge time and the corrected data of the weight of the remaining molten steel at the critical slag discharge time, control the sliding plate hydraulic cylinder to close the ladle sliding plate, thereby preventing the slag in the ladle from being carried into the tundish. (7) After the continuous casting production is completed, the model calculation and slide control of the ladle slag discharge are ended. When the new casting begins, the operations of steps (3) to (6) are repeated.

2. The method for low-cost continuous casting of automotive panel steel to avoid slag runoff from the ladle, as described in claim 1, is characterized in that: In step (4), the corrected data m for the remaining molten steel weight at the critical slag discharge point of the ladle is... ’ , ， Where: m ’ — Corrected data for the remaining molten steel weight at critical slag discharge in the ladle, in tons; m0 — Excess weight of molten steel, which is 1 to 2 tons; m slag —The weight of the steel slag inside the bulk bag is set in tons; m ladle —Set the weight of the empty large package in tons; m cover —The weight of the large bag lid is set in tons.

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