Method and system for determining a series of temperature values of a molten metal bath

Abstract

The invention relates to a method and a system for determining a series of at least two temperature values of a molten metal bath with a device comprising a light cladding wire and a detector. It has proven that the method according to the invention is especially suitable for multiple repeated measurements, wherein a final temperature of the molten metal bath shall be reached.

Description

[0001] The present invention relates to a method and system for determining a series of at least two temperature values ​​for a molten metal pool.

[0002] The temperature of the molten metal pool in a metallurgical vessel is a critical parameter during the metalworking process, determining the quality of the resulting product. A possible method for measuring the temperature of the molten metal pool (specifically, the molten metal pool of iron or steel in the melting environment of an electric arc furnace (EAF)) involves immersing an optical fiber encased in a metal tube into the molten metal. Optical fibers encased in a metal tube are often also referred to as optical cored cables.

[0003] Since heating molten metal is an energy-intensive process, it is desirable to avoid overheating the molten metal; that is, heating it above the critical temperature that allows for optimal handling of the melt.

[0004] To measure the temperature of a molten metal pool, an optical fiber cored wire is supplied to a metallurgical vessel. The leading edge of the optical fiber cored wire is immersed in the molten metal pool, encountering first a hot atmosphere, then a layer of molten slag, and finally the molten metal pool itself. Once a portion of the optical fiber cored wire is submerged below the surface of the molten metal pool, the optical fiber transmits the thermal radiation received from the molten metal to a detector, such as a pyrometer. A suitable instrument can be associated with the detector used to determine the temperature of the molten metal pool. During this measurement, the immersed portion of the optical fiber cored wire can be partially or completely consumed by the molten metal pool. Once the temperature measurement is complete, the leading edge of the optical fiber cored wire is retracted from the molten metal pool. The retracted leading edge becomes a new leading edge for the next temperature measurement.

[0005] Therefore, this device is suitable for on-demand and semi-continuous temperature measurement in the form of a series of immersion cycles. The operator can obtain temperature measurement results without any direct intervention in the harsh environment near the metallurgical vessel.

[0006] To provide accurate measurement results, blackbody conditions must be ensured near the immersion tip of the optical fiber when obtaining the results. The fiber must be immersed to a sufficient depth below the surface of the molten metal pool and at a position representing the temperature of the liquid molten metal pool within the container. On the other hand, deep immersion will increase the buoyancy force on the optical core and increase the consumption of the optical core during the measurement sequence.

[0007] Several prior art documents disclose methods for supplying optical fibers for metal coating to improve the data quality of temperature measurements.

[0008] For example, US2018180484A1 discloses a method suitable for multiple measurement cycles without additional equipment. However, the disclosed method does not take into account the final state to be reached at the end of the melting process; that is, the final temperature at which the melting process should end. It also does not consider the constantly changing conditions during the metal-making process, especially the rising temperature of the molten metal. This may result in unnecessary additional measurements during the process or measurements performed at inappropriate points.

[0009] US2014130636A1 discloses a method for controlling a melting process in an electric arc furnace. Process parameters are obtained to determine the state of the process, and the process is adapted based on the obtained parameters according to predetermined values. While optimization of the process itself is disclosed, optimization of the accompanying measurements is not addressed.

[0010] Given the existing technology, there is a need for a measurement method and system that takes into account the accompanying circumstances of the metal manufacturing process, as well as an efficient way to use the method and system.

[0011] Therefore, the object of the present invention is to provide an improved method for determining a series of at least two temperature values ​​for a molten metal pool, which solves at least one of the problems discussed above. In particular, the object of the method according to the invention is to provide a method that accompanies the metal fabrication process until a final temperature value is reached with a minimum number of temperature measurements. More particularly, the object of the invention is to provide a method that avoids overheating of the molten metal pool. Specifically, one object is to provide a method that minimizes the consumption of optically cored wire during a series of measurements.

[0012] Another object of the present invention is to provide an improved system for determining a series of at least two temperature values ​​for a molten metal pool.

[0013] These objectives are achieved through the subject matter defined in the independent claims.

[0014] This invention provides an apparatus for determining a series of at least two temperature values ​​T of a molten metal pool using a device comprising a cored wire and a detector. mes (n) and T mes (n+1) methods, which include:

[0015] (a) A model F(t) is provided to describe the temperature development of the molten metal pool over time;

[0016] (b) Limiting the critical temperature value T cri ;

[0017] (c) Measure the temperature T of the molten metal pool at time point t(n). mes (n);

[0018] (d) Based on model F(t) and critical temperature T cri and the measured temperature value T mes (n) determines the fitted heating rate R heat (n), where R heat (n) is defined as

[0019] R heat (n)=ΔT heat (n) / Δt;

[0020] (e) Based on the critical temperature value T cri With the measured temperature value T mes The temperature difference ΔT(n) between (n) and the fitted heating rate R heat (n) is used to calculate time point t cal (n+1), where

[0021] ΔT(n)=T cri -T mes (n), and

[0022] t cal (n+1)=t(n)+(ΔT(n) / R heat (n));

[0023] (f) at time point t cal (n+1) Measure the temperature T of the molten metal pool. mes (n+1).

[0024] Furthermore, the present invention provides a series of at least two temperature values ​​T for determining the molten metal pool. mes (n) and T mes A system of (n+1) elements, comprising a device and a module adapted to interact with the device, wherein the device includes an optical cored wire and a detector, and wherein the module includes a storage unit, a processing unit, and a control unit, wherein the storage unit includes:

[0025] (a1) A storage element used to supply a model F(t) that describes the temperature development of a molten metal pool over time;

[0026] (a2) is used to define the critical temperature value T. cri Storage elements;

[0027] The processing unit includes:

[0028] (b1) is used for models based on F(t) and critical temperature T. cri and the measured temperature value T mes Determine the fitted heating rate R heat The processing element, wherein Rheat Defined as

[0029] R heat =ΔT heat / Δt;

[0030] (b2) Used for critical temperature values ​​T cri With the measured temperature value T mes The temperature difference ΔT and the fitted heating rate R between them heat To calculate time point t cal The processing element, in which

[0031] ΔT=T cri -T mes ,and

[0032] t cal =t+(ΔT / R) heat );

[0033] And the control unit includes:

[0034] (c1) Used to measure the temperature T of the molten metal pool mes The control element.

[0035] Preferred embodiments are defined in the dependent claims. Preferred embodiments may be implemented individually or in any possible combination.

[0036] The method according to the invention has proven particularly suitable for repeated measurements in which the final temperature of the molten metal pool should be reached. Typically, the temperature of the molten metal increases between measurements due to continuous heating, and overheating, i.e., heating above the desired final temperature, should be avoided. Furthermore, the method has proven to support efficient application of several measurements to direct heat to the final temperature; that is, to ensure that the target temperature is reached at the end of the process. In other words, underheating at the end of the process can also be avoided. Moreover, the method of the invention allows for optimal timing and number of measurements, resulting in optimized and minimal consumption of the optical cored wire. As used herein, the term "consumption" refers to the disintegration of the optical cored wire, such as, for example, the optical cored wire being melted and dissolved into the molten metal pool, the decomposition or burning of the entire optical cored wire or different portions thereof, etc.

[0037] This invention provides a method for determining a series of at least two temperature values ​​T mes (n) and T mes The (n+1) method. This paper uses a series of temperature values ​​to describe determinations that are repeated at least once. This series of temperature values ​​includes at least the temperature value T. mes (n) and T mes (n+1). Except for T mes (n) and T mesIn addition to (n+1), other temperature values ​​can be determined.

[0038] Throughout this application, variables related to temperature or temperature values ​​will be indicated by the uppercase letter T, while variables related to time points, durations, or time will generally be indicated by the lowercase letter t.

[0039] Variables without a specified index (i.e., (n) or (n+1) etc.) will generally be used to define the variable. Variables with a specified index will be used to refer to the variable in a specific context. For example, T mes This refers to the measured temperature value T. mes The general definition of T, and T mes (n) refers to a specific measured temperature value.

[0040] According to the present invention, the temperature value T can be determined by measuring the temperature. mes Temperature measurement can be, for example, single-point or multi-point measurement, and possibly related data processing.

[0041] Measured temperature value T mes (n) is understood as the temperature value obtained through measurement at a specific time point t(n). Therefore, the temperature value T mes (n+1) is the temperature value obtained at a specific time point t(n+1).

[0042] As used herein, the term "molten metal pool" describes a melt in a container. An alternative term known to those skilled in the art is "molten metal." The molten metal in a molten metal pool is not particularly limited. According to a preferred embodiment, the molten metal is molten steel. The term "molten metal pool" does not exclude the presence of any solid or gaseous portion, including, for example, a non-molten portion of the corresponding metal. A molten metal pool may be covered with a layer of slag.

[0043] The temperature of molten metal varies and generally depends on the composition of the metal and the stage of the melting process. According to a preferred embodiment, the temperature of the molten metal pool is in the range of 1500°C to 1800°C, and more preferably in the range of 1500°C to 1700°C.

[0044] The molten metal pool can be contained in a container including an inlet point adapted to supply the optical cored wire through which it passes. This inlet point can be located in a side wall panel or in the top of the container covering the core.

[0045] According to the present invention, at least two temperature values ​​T are determined using a device including optical cored wire. mes (n) and T mes(n+1). Preferably, the optical core is an optical fiber laterally surrounded by a metal tube. Preferably, the optical fiber is a flexible, transparent fiber. Optical fibers are most commonly used as devices for transmitting light (especially light in the IR wavelength range) between the two ends of a fiber. Preferably, the optical fiber is formed of glass or plastic, more preferably quartz glass. Preferably, the optical fiber is selected from graded refractive index fibers and single-mode step refractive index fibers.

[0046] The metal tube surrounding the optical fiber can completely encircle the fiber, or it can be at least partially open so that the shell does not completely encircle the fiber.

[0047] Preferably, the metal tube surrounding the optical fiber is made of iron or steel, and more preferably stainless steel.

[0048] In a preferred embodiment, the linear density of the optical cored wire can be in the range of 25 g / m to 80 g / m, more preferably in the range of 35 g / m to 70 g / m. The linear density is defined by its mass per unit length.

[0049] Preferably, the optical cored wire is laterally surrounded by at least one additional metal tube, i.e., at least two metal tubes laterally surround the optical fiber. More preferably, the optical cored wire is centrally arranged in at least one additional metal tube.

[0050] Preferably, the at least one additional metal tube does not contact the optical cored wire. More preferably, the gap between these at least two metal tubes is at least partially filled with a material selected from gaseous or solid materials or combinations thereof. The solid material is preferably selected from inorganic materials, natural polymers, synthetic polymers, and combinations thereof. The gaseous material is preferably a gas or a mixture of gases. More preferably, the gas is air or an inert gas.

[0051] According to a preferred embodiment, the optical cored wire includes a plurality of separating elements arranged in at least one metal tube, thereby forming at least one compartment between the separating elements. Here, the term "compartment" refers to the volume between the different separating elements in the tube. The term "separating element" refers to a component arranged inside the tube that subdivides the volume within the tube. Preferably, the separating element is a disc-shaped element arranged inside the tube including an opening through which the optical cored wire extends, and the tube at least partially supports the optical cored wire. The material of the separating element is preferably selected from silicone resin (preferably a two-component silicone resin), rubber, leather, cork, metal, and combinations thereof.

[0052] The optically cored wire is optionally surrounded by at least one additional layer. This at least one additional layer may or may not replace the at least one additional metal tube. In a preferred embodiment, the at least one additional layer comprises a plurality of elements; more preferably, the layer comprises fibers.

[0053] In another preferred embodiment, the material of the at least one additional layer has the form of a mesh, reticulated structure, woven or knitted structure.

[0054] Preferably, the at least one additional layer comprises a non-metallic material, and most preferably an organic material.

[0055] It should be understood that optical cored wires may include any combination of the above configurations. For example, it may be advantageous for the optical cored wire to be laterally surrounded by an additional layer and a second metal tube.

[0056] The apparatus for applying the method according to the invention further includes a detector. The detector is coupled to one end of an optical cored wire and receives optical signals transmitted by the optical fiber, particularly optical signals in the IR wavelength range. Preferably, in the context of this invention, the detector is a pyrometer.

[0057] The optical cored wire has an immersion end and a opposite end. The leading tip of the optical cored wire is the tip of the immersion end. Preferably, when applying the method according to the invention, the optical cored wire is consumed in the direction from the immersion end toward the opposite end, and after each measurement sequence, another portion of the optical cored wire will be the immersion end; that is, a new leading tip is generated after each measurement sequence. The opposite end is connected to the detector and will not be consumed during measurement.

[0058] In step (a) of the method according to the invention, a model F(t) is provided to describe the temperature development of the molten metal pool over time.

[0059] The model F(t) describing the temperature development of a molten metal pool over time is a model that defines the relationship between time and temperature; that is, the model F(t) is adapted to predict the temperature at a specific point in time. In a typical melting process, time is directly related to the electrical energy input.

[0060] Since model F(t) describes the temperature development of the molten metal pool over time, the first derivative F'(t) of model F(t) can be interpreted as the change in temperature over time. In other words, and under the condition of increasing temperature development, the first derivative F'(t) of model F(t) preferably represents the heating rate R of the molten metal pool over time, and can be expressed as...

[0061] R = F'(t) = ΔT / Δt,

[0062] Where ΔT represents the temperature change and Δt represents the duration.

[0063] Preferably, the model F(t) describes the maximum temperature at which the temperature of the molten metal pool develops over time; that is, it assumes a maximum heating rate R for each temperature value. In other words, the temperature of the molten metal pool will not rise faster than this maximum heating rate at a given temperature.

[0064] In an exemplary embodiment, the first derivative F'(t) of the model F(t) describing the temperature development of the molten metal pool over time is a linear function.

[0065] Preferably, the model F(t) describing the temperature development of the molten metal pool over time includes mathematical equations, characteristic curves, or other information defining the relationship between time and temperature of the molten metal pool. It may contain descriptions of the physical properties of the molten metal pool, the characteristics of the metallurgical facility, and the relationships between the corresponding model parameters. Preferably, the physical properties of the molten metal pool are considered in the model F(t).

[0066] Preferably, the model F(t) is derived using a method selected from numerical methods, analytical methods, experimental methods, and combinations thereof.

[0067] Preferably, the model F(t) describing the temperature development of the molten metal pool over time is based on recorded measurements, i.e., data obtained during previous melting processes.

[0068] In a preferred embodiment, the estimated or measured temperature value may be the sole input parameter to a model F(t) describing the temperature development of the molten metal pool over time. In other examples, additional input parameters may be used. Preferably, such additional input parameters may be operating parameters. Here, operating parameters are parameters that define the melting process, such as electrical energy input.

[0069] In a preferred embodiment, the model F(t) describing the temperature development of the molten metal pool over time is derived by a method including the following steps:

[0070] (i) Provide a set of data that correlates the characteristics of a molten metal pool with recorded data of a model F(t) for the development of the temperature of the molten metal pool over time;

[0071] (ii) Provides the characteristics of a molten metal pool;

[0072] (iii) Receive a model F(t) describing the temperature development of the molten metal pool over time from a set of data related to the properties provided by the molten metal pool.

[0073] Preferably, the set of data includes data pairs in which a specific value of one type of data is assigned to a specific value of another type of data. More preferably, the set of data may also include data pairs in which a specific value of one type of data is assigned to a model, a sequence of steps, etc.

[0074] In step (b) of the method according to the invention, a critical temperature value T is defined.cri .

[0075] Critical temperature value T cri "This should be understood as a fixed temperature value. Preferably, the critical temperature value T..." cri This is the predetermined temperature of the molten metal pool; above this temperature, further temperature determination is no longer required. This critical temperature could be, for example, the target temperature of the molten metal pool, at which the melting process will terminate. This temperature is also called the target tapping temperature because when the molten metal pool reaches this temperature, the final step of the metal-making process, tapping, is initiated.

[0076] In step (c) of the method according to the invention, the measured temperature T of the molten metal pool is measured at time point t(n). mes (n).

[0077] Temperature value T mes The measurement of (n) determines the temperature T of the molten metal pool at time point t(n). mes (n).

[0078] To measure the temperature value T mes The system records the radiation emitted from the molten metal pool (especially in the IR wavelength range) and transmitted to the detector by the optical cored wire. The intensity and / or spectral information of the radiation can be processed by a processing unit connected to the detector. Preferably, the tip of the optical cored wire is immersed below the surface of the molten metal pool at the point when this temperature is achieved.

[0079] Preferably, the measured temperature value T is determined. mes This includes measuring a single data point or measuring more than one data point; that is, measuring a series of data points.

[0080] Preferably, the measured temperature value T mes It is the mean of a series of data points. More preferably, a specific temperature value is derived based on the application of an algorithm that processes a series of data points.

[0081] Preferably, the measured temperature value T is determined by measuring the distribution MP. mes .

[0082] Preferably, the measured temperature value T is determined by applying the measurement distribution MP(n). mes (n).

[0083] The measurement distribution MP should be understood as a sequence of steps to obtain a value of interest. In the context of this invention, the value of interest is the temperature of the molten metal pool.

[0084] In a preferred embodiment, measuring the distribution MP defines at least one of the following steps.

[0085] (i) The leading tip of the optical cored wire is positioned above the surface of the molten metal pool;

[0086] (ii) During the time period from t0 to t2, at least one supply rate v fed The tip of the bright cored wire is supplied toward and below the surface of the molten metal pool, wherein the tip of the bright cored wire is below the surface of the molten metal pool during the time period from t1 to t2;

[0087] (iii) Obtain temperature information during the measurement time period from t1 to t2;

[0088] (iv) at a speed v ret The leading tip of the optical cored wire is retracted back to a position above the molten metal pool.

[0089] In other words, preferably, the measurement distribution MP defines at least steps (i) and / or (ii) and / or (iii) and / or (iv). Preferably, the measurement distribution MP defines steps (i), (ii), (iii) and (iv).

[0090] It should be understood that t1 and t2 are later than t0, and t2 is later than t1. t1 is the time point when the tip enters the molten metal pool; that is, the time point when the tip is immersed below the surface of the molten metal pool. t2 is the time point after the tip retracts towards its position above the surface of the molten metal pool.

[0091] Preferably, steps (i), (ii), and (iv) are performed in a sequential order.

[0092] Preferably, step (iii) is performed at least in part during step (ii).

[0093] Those skilled in the art will understand that "providing a front tip" and "supplying a front tip" necessarily include providing and supplying optical cored wire, that is, providing optical cored wire with a front tip and moving optical cored wire with its front tip.

[0094] It should be understood that the supply velocity v fed It refers to the average speed of the tip during its orientation toward and below the surface of the molten metal pool.

[0095] The surface of the molten metal pool can be the surface facing the perimeter of the container, or, in the case of a slag layer, the surface facing the slag layer.

[0096] In a preferred embodiment, the supply of the distribution MP in step (ii) includes at least two supply rates v. fed 1 and v fed 2. It should be understood that the supply rate v fed 1 and vfed 2 refers to the average speed of the tip of the optical cored wire.

[0097] Preferably, the feeding of the distribution MP in step (ii) includes a feeding rate v of the feeding tip during the period from t0 to t1. fed 1 and the second supply rate v of the tip during the period from t1 to t2 fed 2.

[0098] According to a preferred embodiment, the measurement distribution MP is further defined within a static time period from t1 to t2, during which the supply of the optical cored wire tip is paused, or the optical cored wire tip is supplied at a low speed. As used herein, "pause the supply of the tip" means not actively moving the tip. Both alternatives, namely pausing the supply or supplying at a low speed, cause the tip's position to shift towards the surface of the molten metal pool due to consumption. However, the tip remains submerged below the surface of the molten metal pool.

[0099] The low speed is preferably below 0.2 m / s, more preferably below 0.1 m / s.

[0100] In step (d) of the method according to the invention, based on model F(t) and critical temperature value T cri and the measured temperature value T mes (n) determines the fitted heating rate R heat (n), where R heat (n) is defined as

[0101] R heat (n)=ΔT heat (n) / Δt.

[0102] Fitted heating rate R heat (n) can be understood as derived from the temperature value T mes (n) The average expected heating rate until the critical temperature is reached. In other words, R heat (n) should be understood as the expected temperature change ΔT over the duration Δt. heat (n).

[0103] It should be understood that the model F(t) can be applied in such a way that it can be determined with respect to the critical temperature T. cri Relevant time point t cri .

[0104] According to the preferred embodiment, the fitted heating rate R is determined based on the linear fitting of the model F(t). heat (n). More preferably, based on time point t cri The fitted heating rate R is determined by linear fitting of the model F(t) with respect to time point t(n).heat (n).

[0105] Preferably, based on time point t cri The fitted heating rate R is determined by the first derivative of the model F(t) at time point t(n). heat (n). More preferably, by targeting time point t cri The fitted heating rate R is determined by averaging the first derivatives of the model F(t) at time point t(n). heat (n).

[0106] According to the preferred embodiment, the fitted heating rate R is determined based on a model of the heating rate R(t) of the molten metal pool. heat (n), the model is based on time point t cri Time point t(n) and measured temperature value T mes The first derivative of the model F(t) of (n).

[0107] In step (e) of the method according to the invention, based on the critical temperature value T cri With the measured temperature value T mes The temperature difference ΔT(n) between (n) and the fitted heating rate R heat (n) is used to calculate time point t cal (n+1), where

[0108] ΔT(n)=T cri -T mes (n)

[0109] and

[0110] t cal (n+1)=t(n)+(ΔT(n) / R heat (n)).

[0111] Step (e) generates future time point t cal The prediction of (n+1) is that the temperature development of the molten metal pool will follow the fitted heating rate R determined in step (d). heat (n), then the critical temperature T will be reached at that future time point. cri .

[0112] Preferably, the fitted heating rate R heat (n) is higher than the actual heating rate of the molten metal pool. Therefore, at a future time point t cal (n+1), the temperature of the molten metal pool will be lower than the critical temperature T. Cri .

[0113] In step (f) of the method according to the invention, the measured temperature T of the molten metal pool is measured at time point t(n+1).mes (n+1).

[0114] Temperature value T mes The measurement of (n+1) determines the temperature T of the molten metal pool at time point t(n+1). mes (n+1).

[0115] Preferably, the measured temperature value T is determined by applying the measurement distribution MP(n+1). mes (n+1).

[0116] Preferably, the measured temperature value T mes The higher (n) is, the higher the supply rate v of the measurement distribution MP(n+1). fed The higher.

[0117] Preferably, the measured temperature value T mes The higher the value of (n), the shorter the duration of the time interval from t1 to t2 for the measurement distribution MP(n+1).

[0118] Preferably, steps (c) to (f) are performed in a sequential order.

[0119] Preferably, step (a) is performed before step (c), more preferably before step (d), and most preferably before step (e).

[0120] Preferably, the method is performed in one of the following orders:

[0121] (a)-(b)-(c)-(d)-(e)-(f),

[0122] (b)-(a)-(c)-(d)-(e)-(f),

[0123] (b)-(c)-(a)-(d)-(e)-(f), or

[0124] (b)-(c)–(d)-(a)-(e)-(f).

[0125] Preferably, step (b) is performed before step (a), more preferably before step (c), and most preferably before step (d).

[0126] Preferably, the method is performed in one of the following orders:

[0127] (b)-(a)-(c)-(d)-(e)-(f),

[0128] (a)-(b)-(c)-(d)-(e)-(f), or

[0129] (a)-(c)-(b)-(d)-(e)-(f).

[0130] Preferably, the method is performed multiple times. More preferably, the method is performed multiple times until the molten metal pool reaches the critical temperature value T. cri .

[0131] Preferably, the method includes steps (g) to (i):

[0132] (g) Based on the model F(t) and the critical temperature value T cri and the measured temperature value T mes (n+1) is used to determine the fitted heating rate R. heat (n+1), where R heat (n+1) is defined as

[0133] R heat (n+1)=ΔT heat (n+1) / Δt;

[0134] (h) Based on the critical temperature value T cri With this temperature value T mes The temperature difference ΔT(n) between (n) and the fitted heating rate R heat (n) is used to calculate time point t cal (n+2), where

[0135] ΔT(n+1)=T cri -T mes (n+1), and

[0136] t cal (n+2)=t(n+1)+(ΔT(n+1) / R heat (n+1));

[0137] (i) at time point t cal (n+2) Measure the temperature T of the molten metal pool. mes (n+2).

[0138] Preferably, the fitted heating rate R heat (n+1) is higher than the fitted heating rate R heat (n); that is, temperature difference ΔT heat (n+1) is greater than the temperature difference ΔT heat (n).

[0139] Preferably, steps (g) to (i) are performed in a sequential order.

[0140] Preferably, steps (g) to (i) are performed after steps (a) to (f).

[0141] Preferably, the method is performed in one of the following orders:

[0142] (a)-(b)-(c)-(d)-(e)-(f)-(g)-(h)-(i),

[0143] (b)-(a)-(c)-(d)-(e)-(f)-(g)-(h)-(i),

[0144] (b)-(c)-(a)-(d)-(e)-(f)-(g)-(h)-(i), or

[0145] (b)-(c)-(d)-(a)-(e)-(f)-(g)-(h)-(i).

[0146] The present invention also provides a series of at least two temperature values ​​T for determining a molten metal pool. mes (n) and T mes A system of (n+1) includes a device and a module, wherein the module is adapted to interact with the device.

[0147] Preferably, the system is configured to perform the method according to the invention, wherein the method includes the following steps:

[0148] (a) A model F(t) is provided to describe the temperature development of the molten metal pool over time;

[0149] (b) Limiting the critical temperature value T cri ;

[0150] (c) Measure the temperature T of the molten metal pool at time point t(n). mes (n);

[0151] (d) Based on model F(t) and critical temperature T cri and the measured temperature value T mes (n) determines the fitted heating rate R heat (n), where R heat (n) is defined as

[0152] R heat (n)=ΔT heat (n) / Δt;

[0153] (e) Based on the critical temperature value T cri The temperature value T mes The temperature difference ΔT(n) between (n) and the fitted heating rate R heat (n) is used to calculate time point t cal (n+1), where

[0154] ΔT(n)=Tcri -T mes (n), and

[0155] t cal (n+1)=t(n)+(ΔT(n) / R heat (n));

[0156] (f) at time point t cal (n+1) Measure the temperature T of the molten metal pool. mes (n+1).

[0157] For preferred embodiments related to the method of the present invention, refer to the preferred embodiments given above.

[0158] The system according to the invention includes an apparatus comprising an optical cored wire and a detector. For a preferred embodiment relating to the optical cored wire and the detector, reference is made to the preferred embodiment given above.

[0159] The system according to the invention includes modules, wherein the modules include a storage unit, a processing unit, and a control unit.

[0160] Preferably, the storage unit, processing unit, and control unit are configured to interact with each other.

[0161] According to the present invention, the storage unit of the module includes:

[0162] (a1) A storage element for supplying a model F(t) describing the temperature development of the molten metal pool over time; and

[0163] (a2) is used to define the critical temperature value T. cri Storage elements.

[0164] According to the present invention, the processing unit of the module includes

[0165] (b1) is used for models based on F(t) and critical temperature T. cri and the measured temperature value T mes Determine the fitted heating rate R heat The processing element, wherein R heat Defined as

[0166] R heat =ΔT heat / Δt;

[0167] (b2) Used for critical temperature values ​​T cri With the measured temperature value T mes The temperature difference ΔT and the fitted heating rate R between them heat To calculate time point t cal The processing element, in which

[0168] ΔT=T cri -T mes ,and

[0169] t cal =t+(ΔT / R) heat ).

[0170] In a preferred embodiment, the processing unit is configured to process information stored in the storage unit.

[0171] According to the present invention, the control unit of the module includes:

[0172] (c1) Used to measure the temperature T of the molten metal pool mes The control element.

[0173] In a preferred embodiment, the control unit is configured as a control device.

[0174] In a preferred embodiment, the system may include a supply device. In the context of this invention, a supply device can be understood as a means that allows the feeding of a bright cored wire into a pool of molten metal. Such a device may be selected from a feeder, supply control, straightener, and guide tube.

[0175] According to a preferred embodiment, the system may further include a coil adapted to the length of the optical cored wire.

[0176] The basic idea of ​​the invention will then be described in more detail with respect to the embodiments shown in the accompanying drawings.

[0177] However, it should be understood that the present invention is not limited to the precise arrangement and tools shown. In this document:

[0178] Figure 1 Schematic cross-sectional views of different designs of optical cored wire are shown.

[0179] Figure 2 A schematic diagram of an exemplary facility 6 with a molten metal pool 7 is shown, the temperature of which should be determined.

[0180] Figure 3 The position-time plot is shown, indicating the immersion of the tip of the optical cored wire during the application of a representative measurement distribution.

[0181] Figure 4 A position-time plot is shown, indicating the immersion of the tip of the optical cored wire during the application of another representative measurement distribution.

[0182] Figure 5 A schematic diagram of a system according to an embodiment of the present invention is shown.

[0183] Figure 6 A schematic diagram of a module according to an embodiment of the present invention is shown.

[0184] Figure 7 A graph illustrating a method according to an exemplary embodiment of the present invention is shown.

[0185] Figure 1 Schematic cross-sectional views of different designs of optical cored wires according to exemplary embodiments of the present invention are shown. Figure 1 A shows an optical cored wire 1', which includes an optical fiber 2' surrounded by a metal tube 3'.

[0186] Figure 1 B shows an optical cored wire 1”, which includes an optical fiber 2 surrounded by a metal tube 3”. A second metal tube 4” further surrounds the metal tube 3”. The gap between the two metal tubes 5” is not filled with solid material; that is, the gap may include gas or a gas mixture.

[0187] Figure 1 C shows an optical cored wire 1”', which includes an optical fiber 2”' surrounded by a metal tube 3”' and a second metal tube 4”'. The gap between the two metal tubes 5”' is filled with a filler material, such as fibers from organic materials or alkali-free glass.

[0188] Figure 2 A schematic diagram of an exemplary facility 6 with a molten metal pool 7 is shown, the temperature of which should be determined.

[0189] Facility 6 includes a bare cored wire 1, which is at least partially located on and at least partially extended from coil 8 to perform measurements. One end of the bare cored wire 9 is connected to a detector 10, which is then connected to a computer system (not shown) to process the data obtained using the bare cored wire 1 and detector 10. A molten metal pool 7 is contained in a container 11, which can be an electric arc furnace, ladle, tundish, or any container known to those skilled in the art of molten metal handling. The bare cored wire 1 is led into the container 11, which has an inlet point 14, via a feeder 12 and a guide tube 13. The configuration shown is for illustrative purposes only; having a corresponding inlet point is not a prerequisite for the invention.

[0190] The configuration shown illustrates an exemplary measurement position for the optical cored wire 1, wherein the leading tip 15 is immersed in the molten metal pool MB. S Below the surface. In the presented embodiment, the optical cored wire 1 is positioned relative to the molten metal pool MB. S The immersion angle of the surface is 90°. However, this angle can vary depending on the structural details of the metallurgical facility.

[0191] The temperature of the portion of the cored wire 1 extending from the coil 8 to the inlet point of the container 14 can be considered low, ranging from room temperature up to 100°C. Once past the inlet point 14 along the direction of the molten metal pool 7, it first encounters a hot atmosphere up to 1700°C or even higher, followed by a slag layer 17, which in turn follows the molten metal pool 7. The inlet point 14 leading to the container may be equipped with an air-blowing nozzle 18 to prevent metal and slag from penetrating into the guide tube 13.

[0192] To obtain temperature measurement results, the optically cored wire 1 is fed towards the molten metal pool 7 to the desired immersion depth using its leading edge at the immersion end 15. For reliable temperature measurement results, it may be desirable to perform measurements at a more or less fixed immersion depth within the molten metal pool. A suitable supply system 12 will accurately control the supply speed of the optically cored wire 1.

[0193] Following the measurement sequence, the portion of the optically cored wire immersed in the molten metal pool 19 is melted and thus consumed. The length of this portion is denoted by L. C Instructions. After the measurement is performed, the portion of the optical cored wire 20 that is in the hot atmosphere and extends through the slag layer can be fed back into the direction of the coil 8 and can be reused for the next measurement.

[0194] Since the temperature of the molten metal pool 7 is a critical process parameter, it is desirable to understand in detail its development during the metal fabrication process, which is accompanied by a series of measurements. In a typical EAF process, the temperature of the molten metal will increase at a slower rate at lower temperatures compared to higher temperatures.

[0195] In the low-temperature range, the molten metal pool will still contain unmelted portions, while in the higher-temperature range, the molten metal pool contains homogeneous molten metal. Therefore, the full energy input is directed to heating the material, rather than being consumed by the melting of the solid parts.

[0196] Temperature measurements are typically taken after the molten pool has reached a flat surface, usually above 1500°C for most steels. The heating rate at this temperature is typically around 10°C / min. Within the typical target tapping temperature range (usually 1650°C), the heating rate can increase to 80°C / min, depending on the energy input.

[0197] Figure 3 A position-time plot is shown, indicating the immersion of the leading tip of the optical cored wire during the application of a representative measurement distribution. The x-axis represents time, while the y-axis indicates the position of the leading tip. The surface of the molten metal pool (MB) is also shown. SThe position is indicated for orientation. Before the measurement begins; that is, before t0, the tip is positioned at the starting point. This can be inside the metallurgical vessel and near the inlet point; that is, near the point where the cored wire enters the vessel. The cored wire is supplied towards the molten metal pool at a feed rate and fed into the molten metal pool during the duration from t0 to t2. This duration is typically in the range of several seconds. The tip of the cored wire enters the molten metal pool at time t1, that is, t1 is the time point when the tip is immersed below the surface of the molten metal pool. In the graph shown, a single feed rate is applied, but the supply may include several phases with different feed rates. Even a phase without supply may be included during the measurement; that is, a pause phase, such as... Figure 4 The graph shown illustrates another preferred embodiment. Temperature measurements are obtained during the measurement period from t1 to t2. The tip must be immersed below the surface of the molten metal pool to obtain a reliable measurement. Temperature values ​​obtained earlier in the supply may not necessarily represent the bulk temperature of the molten metal pool. After t2, the bright cored wire is retracted from the molten metal pool to a position above the surface. Ideally, the bright cored wire is immersed in the surface L of the molten metal pool. C The lower portion is consumed until t2.

[0198] The time required for the immersed portion of the cored wire to be completely consumed to the surface of the molten metal pool depends on the temperature of the molten metal and the characteristics of the cored wire. These characteristics affecting the melting or consumption behavior of the cored wire include its design and the materials used in its manufacture. For example, a metal tube with a higher wall thickness will melt more slowly than a metal tube of the same material with a thinner wall thickness. In any case, the measurement is always related to the consumption of a portion of the cored wire. Therefore, minimizing the number of measurements minimizes the amount of cored wire consumed.

[0199] Figure 5 A schematic diagram of a system 30 according to an embodiment of the present invention is shown, the system being configured to perform the method of the invention. Therefore, system 30 is configured to supply a model describing the temperature development of a molten metal pool over time. System 30 is also configured to define a critical temperature; for example, a target temperature of the molten metal pool. Furthermore, system 30 is configured to determine a heating rate based on an input critical temperature, a measured temperature, and the model describing the time-dependent temperature development of the molten metal pool. System 30 is also adapted to calculate a time point based on a first time point, the determined heating rate, and a temperature difference. Additionally, system 30 is configured to measure temperature values.

[0200] The system includes a device 40, which includes an optical cored wire and a detector. Additionally, the system includes a module 50. Figure 6A more detailed schematic diagram of module 50 is shown. Module 50 includes a storage unit 60, a processing unit 70, and a control unit 80.

[0201] Exemplary conditions for the method according to the present invention will be given below. Example:

[0202] Install the device including the optical fiber cored wire according to Figure 2 In a representative electric arc furnace (EAF) facility, the optically cored wire consists of graded refractive index fibers with a core diameter of 50 μm and a stainless steel tube with an outer diameter of 1.3 mm. The fiber with the metal tube is embedded in a stainless steel tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm.

[0203] EAF loads the scrap metal and initiates the melting process. The target tapping temperature is 1650℃ (T). Cri ). Figure 7 The expected temperature development over time for a specific metallurgical facility with applied process parameters is shown. The basic model is based on the maximum expected temperature rise from previous process records. The first measurement is initiated based on the cumulative power consumed by the EAF, thus determining the temperature value at 1520 °C (in...). Figure 7 The time point T is represented by t(n) mes (n)). Based on the expected temperature difference ΔT(n) from the measured temperature to the critical temperature of 130°C, and the expected time until the tapping temperature of 4 minutes (until t) is reached. Cri Δt(n)), expected average heating rate R heat (n) is 32.5℃ / minute. Therefore, the time point t(n+1) for the next measurement is set to 4 minutes after the first measurement.

[0204] The second measurement determined the temperature value to be 1600℃ (in Figure 7 The time point T in the example is represented by t(n+1). mes (n+1)). Based on a temperature difference of 50°C and an expected time point of 43 seconds after the second measurement, a third measurement is set 43 seconds after the second measurement to achieve the target tapping temperature; that is, the expected heating rate is 70°C / minute.

[0205] List of icon numbers

[0206] 1, 1', 1”, 1”' Optical cored wire

[0207] 2', 2"', 2"' optical fibers

[0208] 3', 3"', 3"' metal tubes

[0209] 4”, 4”' Second metal tube

[0210] 5”, 5”’ in the gap between the metal tubes

[0211] 6 facilities

[0212] 7 Molten metal pool

[0213] 8 coils

[0214] 9. Opposite ends (the ends of the cored wire connected to the detector)

[0215] 10 detectors

[0216] 11. Containers; metallurgical containers

[0217] 12 feeders

[0218] 13 catheters

[0219] 14 entry points

[0220] 15. Tip of the optical cored wire

[0221] MB S Surface of molten metal pool

[0222] 17 Slag Layer

[0223] 18. Air Blowing Gun

[0224] 19. The portion of the cored wire immersed in the molten metal pool

[0225] L C Length of the cored wire immersed in the molten metal pool

[0226] 20. Sections of cored wire subjected to hot atmosphere and molten slag

[0227] 30 System

[0228] 40 devices

[0229] 50 modules

[0230] 60 storage units

[0231] 70 processing units

[0232] 80 Control Unit

Claims

1. A device for determining a series of at least two temperature values ​​T of a molten metal pool using an apparatus comprising a cored wire and a detector. mes (n) and T mes The method comprises (n+1) steps, wherein the method includes: (a) Provide a model F(t) that describes the temperature development of the molten metal pool over time; (b) Limiting the critical temperature value T cri ; (c) Measure the temperature T of the molten metal pool at time point t(n). mes (n); (d) Based on the model F(t) and the critical temperature value T cri and the measured temperature value T mes (n) determines the fitted heating rate R heat (n), where the fitted heating rate R heat (n) refers to the measured temperature value T. mes (n) until the critical temperature T is reached cri The average expected heating rate, and R heat (n) is defined as R heat (n)=ΔT heat (n) / Δt; Where, ΔT heat (n) represents the critical temperature value T. cri With the measured temperature value T mes The temperature change between (n) and Δt represents the critical temperature value T. cri With the measured temperature value T mes The duration between (n); (e) Based on the critical temperature value T cri With the measured temperature value T mes The temperature difference ΔT(n) between (n) and the fitted heating rate R heat (n) is used to calculate time point t cal (n+1), where ΔT(n)=T cri -T mes (n), and t cal (n+1)=t(n)+(ΔT(n) / R heat (n)); (f) at the time point t cal (n+1) Measure the temperature T of the molten metal pool. mes (n+1).

2. The method according to claim 1, wherein the method comprises: (g) Based on the model F(t) and the critical temperature value T cri and the measured temperature value T mes (n+1) is used to determine the fitted heating rate R. heat (n+1), where the fitted heating rate R heat (n+1) refers to the measurement temperature value T. mes (n+1) until the critical temperature T is reached. cri The average expected heating rate, and R heat (n+1) is defined as R heat (n+1)=ΔT heat (n+1) / Δt; Where, ΔT heat (n+1) represents the critical temperature value T. cri With the measured temperature value T mes The temperature change between (n+1) and Δt represents the critical temperature T. cri With the measured temperature value T mes The duration between (n+1), (h) Based on the critical temperature value T cri With the measured temperature value T mes The temperature difference ΔT(n+1) between (n+1) and the fitted heating rate R heat (n+1) is used to calculate time point t cal (n+2), where ΔT(n+1)=T cri -T mes (n+1), and t cal (n+2)=t(n+1)+(ΔT(n+1) / R heat (n+1)); (i) at the time point t cal (n+2) Measure the temperature T of the molten metal pool. mes (n+2).

3. The method according to claim 2, wherein the fitted heating rate R heat (n+1) is higher than the fitted heating rate R heat (n).

4. The method according to any one of claims 1 to 3, wherein the model F(t) describes the maximum temperature at which the temperature of the molten metal pool develops over time.

5. The method according to any one of claims 1 to 3, wherein the first derivative of the model F(t) describing the temperature development of the molten metal pool over time is a linear function.

6. The method according to any one of claims 1 to 3, wherein the model F(t) describing the temperature development of the molten metal pool over time is based on previous measurements.

7. The method according to any one of claims 1 to 3, wherein the model F(t) describing the temperature development of the molten metal pool over time is based on operating parameters.

8. The method according to any one of claims 1 to 3, wherein the fitted heating rate R is determined based on a linear fit of the model F(t). heat (n).

9. The method according to any one of claims 1 to 3, wherein the method is based on the time point t. cri The fitted heating rate R is determined by the first derivative of the model F(t) at the time point t(n). heat (n).

10. The method according to any one of claims 1 to 3, wherein the model F(t) describing the temperature development of the molten metal pool over time is derived by a method comprising the following steps: (i) Provide a set of data that correlates the characteristics of the molten metal pool with recorded data on the temperature development of the molten metal pool over time; (ii) Provide the characteristics of the molten metal pool; (iii) Receive a model F(t) describing the temperature development of the molten metal pool over time from a set of data related to the characteristics provided by the molten metal pool corresponding to the characteristics provided by the molten metal pool.

11. The method according to any one of claims 1 to 3, wherein the measured temperature value T is determined by applying the measurement distribution MP. mes ,in, Measurement distribution (MP) represents a sequence of steps performed to obtain the temperature of the molten metal pool.

12. The method of claim 11, wherein the measurement distribution MP defines the following steps: (i) Providing the optical cored wire, wherein the tip of the optical cored wire is above the surface of the molten metal pool; (ii) During the time period from t0 to t2, at least one supply rate v fed The leading tip of the optically cored wire is supplied toward and below the surface of the molten metal pool, wherein the leading tip of the optically cored wire is below the surface of the molten metal pool during the time period from t1 to t2; (iii) Obtain temperature information during the measurement time period from t1 to t2; (iv) at a speed v ret The optical cored wire is retracted back to a position above the molten metal pool.

13. The method of claim 12, wherein the measurement distribution MP is further defined as a step within a static time period t1 to t2, during which the supply of the tip of the optical cored wire is suspended, or the tip of the optical cored wire is supplied at a low speed.

14. The method of claim 12, wherein the supply step (ii) is performed by at least two supply rates v fed 1 and v fed 2 limited.

15. A series of at least two temperature values ​​T for determining a molten metal pool mes (n) and T mes A (n+1) system, the system comprising a device and a module, wherein the module is adapted to interact with the device, wherein the device comprises an optical cored wire and a detector, wherein the module comprises a storage unit, a processing unit and a control unit, wherein the storage unit comprises: (a1) A storage element for supplying a model F(t) that describes the temperature development of the molten metal pool over time; (a2) is used to define the critical temperature value T. cri Storage elements; The processing unit includes: (b1) is used for models based on F(t) and critical temperature T. cri and the measured temperature value T mes Determine the fitted heating rate R heat The processing element, wherein the fitted heating rate R heat This refers to the measured temperature value T. mes Until the critical temperature value T is reached cri The average expected heating rate, and R heat Defined as R heat =ΔT heat / Δt; Where, ΔT heat Indicates the critical temperature value T cri With the measured temperature value T mes Temperature changes between And Δt represents the critical temperature value T. cri With the measured temperature value T mes The duration between, (b2) is used based on the critical temperature value T. cri With the measured temperature value T mes The temperature difference ΔT and the fitted heating rate R between them heat To calculate time point t cal The processing element, in which ΔT=T cri -T mes ,and t cal =t+(ΔT / R heat ); And the control unit mentioned therein includes: (c1) Used to measure the temperature T of the molten metal pool mes The control element.

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