A method for calculating the RH-terminated molten steel temperature based on casting temperature requirements

Abstract

This invention discloses a method for calculating the RH end temperature of molten steel based on casting temperature requirements, belonging to the field of iron and steel smelting technology. This method uses model calculations to comprehensively consider the influence of process factors such as the target temperature of the tundish for the steel grade, the liquidus temperature, the time from the end of RH to the start of casting, the process path, the casting cycle, the ladle condition, and wire feeding on temperature, in order to accurately calculate the target RH end temperature of molten steel. This invention uses the calculation of the most suitable end target temperature as the main optimization objective, and can predict the molten steel temperature in the RH refining furnace in real time and accurately during the process, thereby improving the temperature accuracy at the end of the refining process and reducing the number of temperature measurements.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a method for calculating the RH-terminated molten steel temperature based on pouring temperature requirements. Background Technology

[0002] Temperature control during continuous casting is crucial for ensuring the quality, performance, and final process quality of metals or alloys.

[0003] During continuous casting, the tundish temperature must be controlled within a certain range, not falling below the lower limit to ensure that inclusions in the molten steel can float smoothly and improve casting quality. Simultaneously, the tundish temperature must not exceed the upper limit to ensure stable casting speed. However, continuous casting itself does not have the function of adjusting the molten steel temperature; whether the target temperature in the tundish is achieved depends on the accuracy of the molten steel temperature control after refining.

[0004] Currently, the RH end temperature needs to be calculated by the main operator, and the target temperature of the tundish for steel grade casting needs to be manually queried to estimate the waiting time before pouring. Then, the temperature needs to be corrected according to the condition of the ladle to finally obtain the target molten steel temperature at the end of RH.

[0005] However, the current RH end temperature is obtained through manual calculation. Manual calculation is limited by computational power; different operators calculate different temperatures, standards vary, and the calculated temperature deviation is significant. For example, the waiting time before casting begins is only a rough estimate, not accurate to the minute. Furthermore, manual calculations do not adequately consider factors such as the casting cycle, process path, and wire feeding, which affect the temperature drop.

[0006] Invention patent CN03151436.7 discloses a method for real-time prediction of molten steel temperature in an RH refining furnace. This method provides a way to predict the temperature during the RH treatment process, which can replace temperature measurement. The purpose of this patent is to calculate the most suitable final target temperature and to accurately predict the molten steel temperature in the RH refining furnace in real time during the process, thereby improving the temperature accuracy at the end of the refining process and reducing the number of temperature measurements. Summary of the Invention

[0007] This invention aims to provide a new method for calculating the target molten steel temperature at the end of the RH cycle. By using model calculations to improve calculation accuracy and capability, it comprehensively considers the influence of process factors such as the target temperature of the tundish for the steel grade, the liquidus temperature, the time from the end of RH cycle to the start of casting, the process path, the casting cycle, the ladle condition, and wire feeding on the temperature, thereby achieving accurate calculation of the target molten steel temperature at the end of the RH cycle.

[0008] To achieve the above objectives, the present invention mainly adopts the following technical solutions:

[0009] 1. Determine the target molten steel temperature and liquidus temperature in the tundish for each steel grade;

[0010] 2. Determine the time from the end of RH to the start of casting, the continuous casting cycle, the refining path, the ladle condition, and the wire feeding length;

[0011] 3. Calculate the temperature drop from the end of RH to the start of molten steel pouring. The calculation method is shown in Table 1 below:

[0012] Table 1. Calculation of Temperature Drop from the End of RH to the Beginning of Steel Pouring

[0013]

[0014] 4. Determine the condition of the ladle and perform temperature correction based on the condition of the ladle. The temperature correction standards are shown in Tables 2 and 3.

[0015] Table 2 Correction Standards for End Target Temperature of Non-LF Treated Steel Grades

[0016]

[0017] Table 3 Correction Standards for Target Temperature at the End of LF Treatment for Steel Grades

[0018]

[0019]

[0020] 5. Calculate the target molten steel temperature at the end of RH. The target molten steel temperature at the end of RH = the target molten steel temperature in the tundish + the temperature drop of molten steel from the end of RH to the start of pouring + the temperature correction for the ladle condition.

[0021] The beneficial effects of this invention are:

[0022] This invention addresses the shortcomings of existing casting temperature calculations by providing a method for calculating the RH-end molten steel temperature based on casting temperature requirements. This algorithm improves calculation accuracy and capability through model calculation, and comprehensively considers the influence of process factors such as the target temperature of the tundish for the steel grade, the liquidus temperature, the time from the end of RH to the start of casting, the process path, the casting cycle, the ladle condition, and wire feeding on the temperature, thereby achieving accurate calculation of the target RH-end molten steel temperature.

[0023] In this invention, the calculation of the most suitable final target temperature is taken as the main optimization objective. During the process, the temperature of the molten steel in the RH refining furnace can be predicted in real time and accurately, thereby improving the temperature hit rate at the end of the refining process and reducing the number of temperature measurements.

[0024] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0025] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the embodiments. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0027] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, wholes, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] This invention provides a method for calculating the final RH-refining steel temperature based on casting temperature requirements. The algorithm improves calculation accuracy and capability through model calculation, comprehensively considering the influence of process factors such as the target temperature of the tundish for the steel grade, the liquidus temperature, the time from the end of RH refining to the start of casting, the process path, the casting cycle, the ladle condition, and wire feeding on temperature, thus achieving accurate calculation of the target RH-refining steel temperature. This invention uses calculating the most suitable final target temperature as the main optimization objective, and can accurately predict the molten steel temperature in the RH refining furnace in real time during the process, thereby improving the temperature accuracy at the end of the refining process and reducing the number of temperature measurements.

[0029] The following, in conjunction with embodiments, provides a further detailed description of the method for calculating the RH-terminal molten steel temperature required for casting disclosed in this invention.

[0030] The specific calculation process for the target molten steel temperature at the end of the RH cycle in this invention is as follows:

[0031] The model reads the target molten steel temperature and liquidus temperature of the tundish for the steel grade from the L3 system using the tapping mark.

[0032] The model reads the RH treatment time and wire feeding length of the steel grade from the L3 system through the steel tapping mark.

[0033] The model reads the arrival time of the ladle at RH, the planned start time of continuous casting, the planned casting cycle, the ladle status, and the process path of the heat from the L2 system using the heat manufacturing command number.

[0034] The calculation method for the time from the end of RH to the start of continuous casting is as follows: Time from the end of RH to the start of continuous casting = Start of continuous casting - Time when the ladle arrives at RH - 6 min - RH processing time.

[0035] The calculation formulas for the temperature drop from the end of the RH cycle to the start of molten steel pouring are shown in Table 1. The selection criteria for the formulas are as follows:

[0036] If the wire feeding length is 0 and the process path identifier is not LF, use formula number 1.

[0037] If the wire feeding length is greater than 0 and the process path identifier is not LF, use formula number 2.

[0038] For wire feeding length > 0 and process path identifier LF processing, use formula number 3.

[0039] For steel grades with a wire feed length of 0 and process path identification LF, use formula number 4.

[0040] Based on the process path and ladle condition standards, determine the ladle condition temperature correction values ​​according to Tables 2 and 3. For process path identified as non-LF treatment heats, the standards in Table 2 are adopted; for process path identified as LF treatment heats, the standards in Table 3 are adopted.

[0041] RH end target molten steel temperature = tundish target molten steel temperature + RH end to pouring molten steel temperature drop + ladle condition temperature correction.

[0042] Example

[0043] Manufacturing order number 23154483, steel tapping mark DT0145D1.

[0044] L3 system steel grade manufacturing standards: tundish target molten steel temperature 1563℃, liquidus temperature 1536℃, wire feed length 0, RH treatment time 22min.

[0045] L2 system: RH arrival time 16:45:35, continuous casting planned start time 17:36:00, continuous casting cycle 50min, ladle condition 21A, process path R1.

[0046] Time from RH end to continuous casting start = Continuous casting start time - Ladle arrival time at RH - 6 min - RH processing time. = 17:36:00 - 16:45:35 - 6 min - 22 min = 22 min.

[0047] With a wire feeding length of 0 and a process path of R1, use Formula 1 to calculate the temperature.

[0048] Temperature drop from the end of RH to the start of casting = 22.3 + 0.33 * time from the end of RH to the start of continuous casting - 0.0116 * liquidus temperature + 0.312 * continuous casting cycle = 22.3 + 0.33 * 22.5 - 0.0116 * 1536 + 0.312 * 50 = 27.5℃.

[0049] The ladle status is marked 21A, the process path is R1 (non-LF processing), and the ladle temperature correction is 0℃.

[0050] The calculated target molten steel temperature at the end of the RH (Reverse Flow Rate) was 1563 + 27 + 0 = 1590℃. The actual measured molten steel temperature at the end of the RH was 1588℃, and the measured temperature in the continuous casting tundish was 1561℃. The required tundish temperature range for the steel grade is 1556-1571℃, with a target of 1563℃. The measured molten steel temperature met the target.

[0051] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for calculating the RH-terminated molten steel temperature based on casting temperature requirements, characterized in that: The temperature algorithm includes: (1) Determine the target molten steel temperature and liquidus temperature in the tundish for the steel grade; (2) Determine the time from the end of RH to the start of casting, the continuous casting cycle, the refining path, the ladle condition and the wire feeding length; (3) Calculate the temperature drop of molten steel from the end of RH to the start of pouring. The calculation method is shown in Table 1: Table 1. Calculation of Temperature Drop from the End of RH to the Beginning of Steel Pouring (4) Determine the ladle condition and perform temperature correction based on the ladle condition. The temperature correction standards are shown in Tables 2 and 3. Table 2 Correction Standards for End Target Temperature of Non-LF Treated Steel Grades Table 3 Correction Standards for Target Temperature at the End of LF Treatment for Steel Grades (5) Calculate the target molten steel temperature at the end of RH. The target molten steel temperature at the end of RH = the target molten steel temperature in the tundish + the temperature drop of molten steel from the end of RH to the start of pouring + the temperature correction for the ladle condition.

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