Method for precisely controlling chemical composition and quantity of high alloy steel

Abstract

The present application relates to the present application relates to the field of metallurgy, specifically relates to a kind of method for precisely controlling high alloy steel chemical composition and molten steel quantity.The method for precisely controlling high alloy steel chemical composition and molten steel quantity, first is to obtain molten steel model parameter and alloy grading parameter, alloy is graded using alloy grading parameter, establishes alloy input quantity calculation model, according to the grading result, the alloy input quantity and alloy composition are calculated, finally, the alloy composition and molten steel target weight are verified, and the result is transmitted to alloy feeding system to smelt high alloy steel.The method of the present application can quickly calculate the addition amount of various alloys, and can realize the purpose of precisely controlling the chemical composition and molten steel quantity after smelting.The present application can also greatly reduce the time required for smelting high alloy steel, greatly reduce production cost, simplify smelting process, improve the degree of precise control of molten steel quantity and chemical composition, and improve smelting efficiency.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to a method for precisely controlling the chemical composition and molten steel quantity of high alloy steel. Background Technology

[0002] High-alloy steel is characterized by a composition of Mn≥0.20%, Cr≥1.50%, Ni≥0.10%, and Mo≥0.30%. Its chemical composition may contain W, Co, etc., and the total amount of various alloys added during the smelting process is greater than 5% of the initial molten steel. High-alloy steel also contains two or more of the following elements: Mn, Cr, Ni, Mo, Co, W, Nb, B, N, and V, and at least two of these elements have a content >1.0%.

[0003] In the steelmaking process, due to factors such as application, cost, and technology, there are numerous types of ferroalloys, each with a complex composition. Combined with the limitations on the element content in the original steel grades, this makes the alloying process extremely complex. This not only affects alloying efficiency but also the precise control of molten steel volume, hindering cost control and reducing product competitiveness, thus failing to contribute effectively to the high-quality development of enterprises. For example, ferrochrome includes high-carbon, medium-carbon, low-carbon, and micro-carbon ferrochrome. The main components of these ferrochromes are Cr and Fe, and their carbon content, as well as residual elements such as silicon, aluminum, and phosphorus, varies depending on the grade. The addition of different ferroalloys introduces these residual elements into the molten steel, affecting the content of carbon, silicon, aluminum, and other elements in the steel. Similarly, ferromanganese also comes in different grades: high-carbon ferromanganese, medium-carbon ferromanganese, and metallic manganese, and the alloying process also affects the content of elements such as carbon.

[0004] In the prior art, Chinese patent CN110764412A discloses a method for controlling the amount of alloy input in steelmaking. The specific control method disclosed is as follows: (1) Obtain model parameters according to the steel grade being smelted, including the target composition of molten steel, the initial composition of molten steel, the weight of molten steel, as well as the content of alloy elements, the price of alloy elements, and the yield of alloy elements; (2) Based on the model parameters obtained in step (1), while considering the upper and lower limit constraints of the target alloy elements, relax the middle limit constraint of the target alloy elements, and establish a linear programming model M1 for the amount of alloy input. If the linear programming model M1 has a solution, then by solving the linear programming model M1, the alloy combination and alloy input amount that meet the target composition requirements are obtained, and the process proceeds to step (4); otherwise, no matter how the alloy ratio is carried out, there will be some alloy input. If the content of gold exceeds the upper and lower limits of the target composition of molten steel, proceed to step (3); (3) For alloy elements without a middle limit requirement, relax the upper and lower limit constraints of the target; for alloy elements with a middle limit requirement, relax the middle limit constraint of the target without considering the upper and lower limit constraints of the target. Establish a linear programming model M2 for the amount of alloy input, solve the linear programming model M2, and obtain the alloy combination and alloy input amount that meet the target composition requirements of molten steel; (4) Based on the alloy input amount and the initial state of molten steel, estimate the content of each alloy element in the molten steel at the end of smelting; (5) If the estimated alloy element content meets the requirements of the target composition of molten steel, confirm the alloy ratio and its input amount, and transmit it to the alloy feeding control system to realize the control of the alloy input amount in steelmaking. However, this method does not consider the dilution effect of the alloy added in the same batch on other elements, and the alloy often contains other elements. The influence of other elements in the alloy is not considered in the calculation model, making it difficult to accurately control the content of each alloy element.

[0005] Chinese patent CN103602774A discloses a method for calculating the alloy material list in steelmaking areas. Specifically, it discloses the selection of alloys to be added, estimates the initial addition amount of each alloy, and finally obtains the final alloy ratio and input amount through iterative calculations. This method first determines the alloys to be added and then calculates the alloy addition amount. However, the selected alloys may not all meet the ratio requirements, and it is difficult to simultaneously achieve the target alloy weight. Furthermore, this method does not consider the differences caused by adding multiple alloys simultaneously, nor does it consider the mutual interference between multiple components within a single alloy.

[0006] Neither CN110764412A nor CN103602774A considered cost factors during selection. They did not explicitly base their alloy selection on alloy grade or price, but instead simply chose one alloy to begin the alloy calculations. However, in actual production, the use of alloys places great emphasis on cost-effectiveness, i.e., the principle of low price.

[0007] Therefore, providing a new method for precisely controlling the chemical composition and molten steel quantity of high alloy steel is of great significance. Summary of the Invention

[0008] To overcome the above technical defects, this invention provides a method for precisely controlling the chemical composition and molten steel quantity of high alloy steel. It fully considers the influence of alloy weight on molten steel weight, the dilution effect of alloy on other elements, the mutual influence of the content of multiple elements in an alloy, and the price factor of the alloy. It can quickly calculate the amount of various alloys to be added, thereby achieving the goal of precisely controlling the chemical composition and molten steel quantity, and can also achieve low-cost production.

[0009] A method for precisely controlling the chemical composition and molten steel quantity of high alloy steel, the method being as follows:

[0010] 1) Obtain the steel model parameters based on the steel grade being smelted, including the initial weight of the molten steel X 初 Initial composition of molten steel, target weight of molten steel X 目 ±x and the target composition of molten steel, and the control range of molten steel composition; where X 目 +x represents the upper limit of the target weight of molten steel, X 目 -x indicates the lower limit of the target weight of molten steel;

[0011] 2) Obtain alloy grading parameters based on the target composition and initial composition of the molten steel obtained in step 1), including alloy price, main elements and content of the alloy, and minor elements and content of the alloy.

[0012] 3) Based on the alloy grading parameters obtained in step 2), first consider the main elements of the alloy to group the alloys, then consider the content of minor elements in the alloy to grade the alloys in each group from high to low, and finally consider the price of the alloy to adjust the graded alloys from low to high, and establish an alloy grading model; input the alloy grading parameters into the alloy grading model, and output s grading levels of the alloy according to the alloy grading model, including the first grade alloy, the second grade alloy, ..., the (s-1)th grade alloy, and the sth grade alloy;

[0013] 4) Based on the steel model parameters obtained in step 1), while considering the middle and upper limits of the target content of all main elements, select any element from the secondary elements as the target element, preset the operation space ψ+y of the target element content, and establish the alloy input calculation model α1.

[0014] Input the first-level alloy and element content corresponding to the main element in step 3) into the alloy input amount calculation model α1, and output the input amount of each first-level alloy and the first composition of the molten steel according to the alloy input amount calculation model α1.

[0015] If the calculated content of the target element in the first component is < ψ+y, then there is a solution. Output the alloy input amount of each first-level alloy and proceed to step 7); where ψ represents the middle limit of the target element and ψ+y represents the upper limit of the operating space.

[0016] If the calculated content of the target element is greater than ψ+y, there is no solution. At the same time, output the calculated input of each first-level alloy and the calculation result of the first composition of the molten steel, and proceed to step 5).

[0017] 5) Based on the difference ε between the target element content and the operating space ψ+y in the first composition calculation result of step 4), and the first-level alloy containing the first main element corresponding to the target element, while considering the mid-limit and upper-lower limit constraints of the target content of all main elements, consider the reduction of the first-level alloy corresponding to the difference ε, and the increase of the second-level alloy corresponding to the reduction of the first-level alloy of the first main element, and establish an alloy input calculation model α2; input the calculated input of the first-level alloy, the first composition calculation result, and the second-level alloy and element content corresponding to the first main element into the alloy input calculation model α2, and output the addition amount of each first-level alloy and second-level alloy and the second composition of the molten steel according to the alloy input calculation model α2;

[0018] If the calculated content of the target element in the second component is < ψ+y, then there is a solution. Output the input amounts of the first-level alloy and the second-level alloy, and proceed to step 7).

[0019] If the calculated content of the target element in the second component is greater than ψ+y, there is no solution. An inner loop is established based on the alloy input calculation model α2. If the calculated content of the target element is less than ψ+y after the inner loop increases to the t-th alloy, there is a solution. Output the input of each alloy and the t-th component. Where 2 < t ≤ s.

[0020] If the calculated content of the target element is greater than ψ+y after the inner loop increases to the s-th level alloy containing the first main element, then there is no solution and proceed to step 6);

[0021] 6) Based on the difference ε between the target element and the operating space ψ in the first calculated component in step 4), and the first-level alloy containing the second main element corresponding to the target element, while considering the middle and upper limits of the target main element, we also consider the reduction of the first-level alloy containing the second main element corresponding to the difference ε, and the increase of the second-level alloy containing the second main element corresponding to the reduction of the first-level alloy, and establish the alloy input calculation model α3.

[0022] Input the calculated input amount of the first-level alloy (step 4), the calculation results of the first composition, and the second-level alloy containing the second main element and its element content into the alloy input calculation model α3. Based on the alloy input calculation model α3, output the input amount of each alloy and the calculated composition of the molten steel.

[0023] If the calculated content of the target element in the calculated composition of the molten steel is less than ψ+y, then there is a solution. Output the input amount of each alloy and proceed to step 7).

[0024] If the calculated content of the target element is greater than ψ+y, there is no solution. An inner loop is established for the calculation model α3 based on the alloy input amount. If the content of the target element in the calculated composition of the molten steel is less than ψ+y after the inner loop increases to the u-th alloy level, there is a solution. The input amount of each alloy is output. Where u≤s.

[0025] If, after the inner loop increases to the s-th level alloy containing the second principal element, the content of the target element in the calculated composition of the molten steel is greater than ψ+y, then there is no solution; confirm whether there is still an alloy containing the target element and the nth principal element. If so, establish an alloy input calculation model αn+1 to solve it; if not, consider relaxing the operation space ψ+y and return to step 4); where 2 < n ≤ the number of all principal elements;

[0026] 7) Based on the alloy input amounts in steps 4)-6), and considering the upper and lower limits of the target values ​​for all major and minor elements, establish an alloy composition calculation verification model; combine the alloy input amounts, element contents, and initial weight of molten steel X 初 1. Input the initial composition model parameters of molten steel into the alloy composition calculation and verification model. If the calculated content of all minor elements meets the requirements of the target upper and lower limits, the verification has a solution. Output the total calculated amount of molten steel and proceed to step 7). If the calculated content of any minor element is not within the target upper and lower limits, there is no solution. Locate the minor element, take it as the target element, and return to step 4).

[0027] 8) The total amount of molten steel output in step 7) must satisfy the target weight of molten steel X. 目 If the requirement is ±x, then the initial weight of the molten steel is X. 初 The results of the alloy input amount are transmitted to the alloy feeding system for smelting.

[0028] If the calculated total amount of molten steel J does not meet the target weight X of molten steel 目 If ±x is required, then the total calculated amount of molten steel is compared with the target weight X of the molten steel. 目 weight difference ε 重 According to the initial weight of molten steel X 初 The weight ratio of the molten steel and alloy is adjusted according to the weight of the alloy input, and the corresponding weight of the molten steel and alloy is transmitted to the alloy feeding system for smelting.

[0029] In one specific embodiment of the present invention, step 3), grouping the alloys considering the main elements of the alloy, specifically involves:

[0030] When an alloy contains a main element, the main element is used as the grouping criterion, and alloys containing the main element are selected as a group.

[0031] When an alloy contains two or more main elements, the alloy is classified into groups for each main element.

[0032] In one specific embodiment of the present invention, step 3), classifying the alloys within each group based on the content of minor elements in the alloy from high to low, specifically involves:

[0033] Based on the grouping of each main element, a table of secondary element content is established for each group.

[0034] Based on the minor elements, the content table of each minor element is filtered level by level to obtain the alloy sorting order results corresponding to the content of each minor element from high to low. If the alloy sorting order results of all minor elements are the same, the alloy sorting order results are merged and output. If any two or more alloy sorting order results are the same, the same alloy sorting order results are merged and output, and the sorting order results of other alloys are also output.

[0035] The alloys are classified according to their sorting order, and the classification result parameters are output, including the main element, minor element, alloy classification grade, and alloy price.

[0036] In one specific embodiment of the present invention, classifying alloys within each group based on the content of minor elements in the alloy from high to low further includes verifying the alloys in different groups, the verification including:

[0037] Check if the same alloy exists in all groups. If so, locate the alloy classification level of the same alloy in each group.

[0038] Retain the same alloys in the higher alloy classification group, delete the same alloys in other groups, and re-output the classification result parameters according to the sorting order in each group.

[0039] In one specific embodiment of the present invention, in step 3), the number of the s grade levels is less than or equal to the number of alloys in each group.

[0040] In a specific embodiment of the present invention, in steps 4)-6), in the alloy input calculation model α1~αn+1, the alloy input is calculated based on the difference between the content of major elements in the initial composition of molten steel and the middle limit of the content of major elements in the target composition of molten steel, and the content of minor elements is calculated based on the input of each alloy.

[0041] In one specific embodiment of the present invention, in step 5), if the reduction of the first-level alloy containing the first main element is less than the amount of the first-level alloy added, then the increase of the second-level alloy containing the first main element is calculated according to the amount of the first-level alloy added.

[0042] In one specific embodiment of the present invention, in step 6), if the reduction of the first-level alloy containing the second main element is less than the amount of the first-level alloy added, then the increase of the second-level alloy containing the second main element is calculated according to the amount of the first-level alloy added.

[0043] In one specific embodiment of the present invention, the high alloy steel is a type of steel in which the total amount of alloy added is greater than 5% of the initial molten steel.

[0044] In one specific embodiment of the present invention, step 8), reducing or increasing the corresponding weight of molten steel and alloy, specifically involves:

[0045] When ε 重 When x > 0, reduce the corresponding weight of molten steel and alloy by weight ratio;

[0046] When ε 重 When -x < 0, increase the weight of molten steel and alloy by weight ratio.

[0047] The beneficial effects of this invention are as follows: This invention can quickly calculate the amount of various alloys added, achieving precise control over the chemical composition and steel quantity after smelting; this invention can also significantly reduce the time required for smelting high-alloy steel, greatly reduce production costs, simplify the smelting process, improve the precision control of steel quantity and chemical composition, and improve smelting efficiency; the method of this invention prioritizes the main elements of the target molten steel, and then adjusts the content of secondary elements by adjusting the alloy dosage of the main elements, which can quickly obtain the alloy dosage for smelting high-alloy steel, making it more convenient and faster to control the chemical composition of high-alloy steel, providing a basis for preparing high-alloy steel using multiple alloys, simplifying the complexity of alloy calculation, and at the same time, this invention also considers the total amount of target molten steel, avoiding waste in smelting steel and alloys, and enabling more precise production of high-alloy steel. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0049] A method for precisely controlling the chemical composition and molten steel quantity of high alloy steel, the method being as follows:

[0050] 1) Obtain the steel model parameters based on the steel grade being smelted, including the initial weight of the molten steel X 初 Initial composition of molten steel, target weight of molten steel X 目±x and the target composition of molten steel, and the control range of molten steel composition; where X 目 +x represents the upper limit of the target weight of molten steel, X 目 -x indicates the lower limit of the target weight of molten steel;

[0051] 2) Obtain alloy grading parameters based on the target composition and initial composition of the molten steel obtained in step 1), including alloy price, main elements and content of the alloy, and minor elements and content of the alloy.

[0052] 3) Based on the alloy grading parameters obtained in step 2), first consider the main elements of the alloy to group the alloys, then consider the content of minor elements in the alloy to grade the alloys in each group from high to low, and finally consider the price of the alloy to adjust the graded alloys from low to high, and establish an alloy grading model; input the alloy grading parameters into the alloy grading model, and output s grading levels of the alloy according to the alloy grading model, including the first grade alloy, the second grade alloy, ..., the (s-1)th grade alloy, and the sth grade alloy;

[0053] 4) Based on the steel model parameters obtained in step 1), while considering the middle and upper limits of the target content of all main elements, select any element from the secondary elements as the target element, preset the operation space ψ+y of the target element content, and establish the alloy input calculation model α1.

[0054] Input the first-level alloy and element content corresponding to the main element in step 3) into the alloy input amount calculation model α1, and output the input amount of each first-level alloy and the first composition of the molten steel according to the alloy input amount calculation model α1.

[0055] If the calculated content of the target element in the first component is < ψ+y, then there is a solution. Output the alloy input amount of each first-level alloy and proceed to step 7); where ψ represents the middle limit of the target element and ψ+y represents the upper limit of the operating space.

[0056] If the calculated content of the target element is greater than ψ+y, there is no solution. At the same time, output the calculated input of each first-level alloy and the calculation result of the first composition of the molten steel, and proceed to step 5).

[0057] In step 4), the alloy input calculation model α1 calculates the composition difference of each main element based on the input steel model parameters, especially the initial composition and target composition of the steel. Then, it calculates the addition amount of each first-level alloy based on the composition difference. Based on the addition amount of each first-level alloy, the initial weight and initial composition of the steel, the first composition is calculated. If the target element in the first composition meets the requirements of the operating space, the solution outputs the first composition and its content. Of course, if other minor elements in the first composition do not meet the requirements, the minor elements that do not meet the upper and lower limits of the target composition are used as the target elements. In subsequent steps, the alloy input amount is adjusted or new alloys are added so that all main and minor elements meet the upper and lower limits of the target composition.

[0058] 5) Based on the difference ε between the target element content and the operating space ψ+y in the first composition calculation result of step 4), and the first-level alloy containing the first main element corresponding to the target element, while considering the mid-limit and upper-lower limit constraints of the target content of all main elements, consider the reduction of the first-level alloy corresponding to the difference ε, and the increase of the second-level alloy corresponding to the reduction of the first-level alloy of the first main element, and establish an alloy input calculation model α2; input the calculated input of the first-level alloy, the first composition calculation result, and the second-level alloy and element content corresponding to the first main element into the alloy input calculation model α2, and output the addition amount of each first-level alloy and second-level alloy and the second composition of the molten steel according to the alloy input calculation model α2;

[0059] If the calculated content of the target element in the second component is < ψ+y, then there is a solution. Output the input amounts of the first-level alloy and the second-level alloy, and proceed to step 7).

[0060] If the calculated content of the target element in the second component is greater than ψ+y, there is no solution. An inner loop is established based on the alloy input calculation model α2. If the calculated content of the target element is less than ψ+y after the inner loop increases to the t-th alloy, there is a solution. Output the input of each alloy and the t-th component. Where 2 < t ≤ s.

[0061] If the calculated content of the target element is greater than ψ+y after the inner loop increases to the s-th level alloy containing the first main element, then there is no solution and proceed to step 6);

[0062] 6) Based on the difference ε between the target element and the operating space ψ in the first calculated component in step 4), and the first-level alloy containing the second main element corresponding to the target element, while considering the middle and upper limits of the target main element, we also consider the reduction of the first-level alloy containing the second main element corresponding to the difference ε, and the increase of the second-level alloy containing the second main element corresponding to the reduction of the first-level alloy, and establish the alloy input calculation model α3.

[0063] Input the calculated input amount of the first-level alloy (step 4), the calculation results of the first composition, and the second-level alloy containing the second main element and its element content into the alloy input calculation model α3. Based on the alloy input calculation model α3, output the input amount of each alloy and the calculated composition of the molten steel.

[0064] If the calculated content of the target element in the calculated composition of the molten steel is less than ψ+y, then there is a solution. Output the input amount of each alloy and proceed to step 7).

[0065] If the calculated content of the target element is greater than ψ+y, there is no solution. An inner loop is established for the calculation model α3 based on the alloy input amount. If the content of the target element in the calculated composition of the molten steel is less than ψ+y after the inner loop increases to the u-th alloy level, there is a solution. The input amount of each alloy is output. Where u≤s.

[0066] If, after the inner loop increases to the s-th level alloy containing the second principal element, the content of the target element in the calculated composition of the molten steel is greater than ψ+y, then there is no solution; confirm whether there is still an alloy containing the target element and the nth principal element. If so, establish an alloy input calculation model αn+1 to solve it; if not, consider relaxing the operation space ψ+y and return to step 4); where 2 < n ≤ the number of all principal elements;

[0067] 7) Based on the alloy input amounts in steps 4)-6), and considering the upper and lower limits of the target values ​​for all major and minor elements, establish an alloy composition calculation verification model; combine the alloy input amounts, element contents, and initial weight of molten steel X 初 1. Input the initial composition model parameters of molten steel into the alloy composition calculation and verification model. If the calculated content of all minor elements meets the requirements of the target upper and lower limits, the verification has a solution. Output the total calculated amount of molten steel and proceed to step 7). If the calculated content of any minor element is not within the target upper and lower limits, there is no solution. Locate the minor element, take it as the target element, and return to step 4).

[0068] 8) The total amount of molten steel output in step 7) must satisfy the target weight of molten steel X. 目 If the requirement is ±x, then the initial weight of the molten steel is X. 初 The results of the alloy input amount are transmitted to the alloy feeding system for smelting.

[0069] If the calculated total amount of molten steel J does not meet the target weight X of molten steel 目 If ±x is required, then the total calculated amount of molten steel is compared with the target weight X of the molten steel. 目 weight difference ε 重 According to the initial weight of molten steel X 初 The weight ratio of the molten steel and alloy is adjusted according to the weight of the alloy input, and the corresponding weight of the molten steel and alloy is transmitted to the alloy feeding system for smelting.

[0070] In some instances, step 3), which involves grouping the alloys based on their principal elements, specifically involves:

[0071] When an alloy contains a main element, the main element is used as the grouping criterion, and alloys containing the main element are selected as a group.

[0072] When an alloy contains two or more main elements, the alloy is classified into groups for each main element.

[0073] For example, high-carbon ferrochrome uses chromium as the main element and carbon as the secondary element; alloys in the same group as high-carbon ferrochrome include medium-carbon ferrochrome, low-carbon ferrochrome, and micro-carbon ferrochrome.

[0074] For example, in chromium nitride alloys, each element is considered as a major element, and nitrogen can be either a major or minor element. When it is clear that nitrogen needs to be added to high-alloy steel, nitrogen is taken as the major element, and chromium nitride is grouped into a group based on nitrogen. In the alloy addition calculation model, the amount of chromium nitride added is calculated first, and then the amount of chromium added is determined based on the amount of chromium nitride added. Finally, when calculating the alloy addition amount in the chromium element group, the amount of chromium added by chromium nitride is subtracted to determine the final addition amount of each alloy in each element group. However, when it is clear that nitrogen is not needed in high-alloy steel, chromium nitride is taken as the major element. But since the addition of chromium nitride will introduce nitrogen impurities into the high-alloy steel, when grouping based on chromium, chromium nitride should be ranked as low as possible in the grouping.

[0075] In some instances, step 3), which classifies the alloys within each group based on the content of minor elements from high to low, specifically involves:

[0076] Based on the grouping of each main element, a table of secondary element content is established for each group.

[0077] Based on the minor elements, the content table of each minor element is filtered level by level to obtain the alloy sorting order results corresponding to the content of each minor element from high to low. If the alloy sorting order results of all minor elements are the same, the alloy sorting order results are merged and output. If any two or more alloy sorting order results are the same, the same alloy sorting order results are merged and output, and the sorting order results of other alloys are also output.

[0078] The alloys are classified according to their sorting order, and the classification result parameters are output, including the main element, minor element, and alloy classification level.

[0079] In this invention, the main elements are usually metallic elements such as chromium, manganese, molybdenum, and titanium, while the minor elements are usually non-metallic elements such as carbon, phosphorus, and sulfur. The groups of each alloy are based on the main elements contained in the alloy, and the classification is based on the order of the content of minor elements in the grouped alloys.

[0080] In some instances, classifying alloys within each group based on the content of minor elements from high to low also includes verifying the alloys in different groups, the verification including:

[0081] Check if the same alloy exists in all groups. If so, locate the alloy classification level of the same alloy in each group.

[0082] Retain the same alloys in the higher alloy classification group, delete the same alloys in other groups, and re-output the classification result parameters according to the sorting order in each group.

[0083] In some instances, in step 3), the number of the s grade levels is less than or equal to the number of alloys in each group.

[0084] In some instances, in steps 4)-6), in the alloy input calculation model α1~αn+1, the alloy input is calculated based on the difference between the content of major elements in the initial composition of molten steel and the middle limit of the content of major elements in the target composition of molten steel, and the content of minor elements is calculated based on the input of each alloy.

[0085] In some instances, in step 5), if the reduction in the amount of the first-level alloy containing the first main element is less than the amount of the first-level alloy added, then the increase in the amount of the second-level alloy containing the first main element is calculated based on the amount of the first-level alloy added.

[0086] In some instances, in step 6), if the reduction in the amount of the first-level alloy containing the second main element is less than the amount of the first-level alloy added, then the increase in the amount of the second-level alloy containing the second main element is calculated based on the amount of the first-level alloy added.

[0087] In one specific embodiment of the present invention, the high alloy steel is a type of steel in which the total amount of alloy added is greater than 5% of the initial molten steel.

[0088] The high-alloy steel of the present invention is any one of 25Cr2Ni4MoV, 14Cr10NiMoWVNbN, and 13Cr9Mo2Co3W2NNbB.

[0089] In one specific embodiment of the present invention, step 8), reducing or increasing the corresponding weight of molten steel and alloy, specifically involves:

[0090] When ε 重 When x > 0, reduce the corresponding weight of molten steel and alloy by weight ratio;

[0091] When ε 重 When -x < 0, increase the weight of molten steel and alloy by weight ratio.

[0092] This invention provides a method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel. By classifying the alloy, the method first ensures that the content of the main elements is within the upper and lower limits of the target composition during model calculation. Then, without affecting the content of the main elements, the method introduces the next grade of alloy to adjust the content of minor elements that do not meet the operating space requirements. Ultimately, the content of both main and minor elements in the target composition of the molten steel meets the requirements. This method can achieve the goal of precisely controlling the chemical composition and molten steel quantity of the smelted high-alloy steel, with higher precision and more accurate matching of the smelted product to the requirements of the high-alloy steel composition limit.

[0093] To further demonstrate the effectiveness of the method of the present invention in improving the precise control of molten steel quantity and chemical composition, the following embodiments are provided:

[0094] Example 1

[0095] This embodiment takes refined 25Cr2Ni4MoV high alloy steel as an example. The initial molten steel quantity is 50t, the target molten steel quantity is 53t, the molten steel quantity is retained to one decimal place, and the second decimal place is rounded off. The acceptable error of the target molten steel quantity is ±0.1t. The alloy yield is considered to be 100% in the calculation.

[0096] The chemical composition requirements (mass percentage) for initial molten steel and target molten steel are shown in Table 1.

[0097] Table 1

[0098]

[0099] Note: In Table 1, "-" represents 0.

[0100] The results of the alloy and chemical element content (mass percentage / %) that can be used to smelt this high alloy steel are shown in Table 2.

[0101] Table 2

[0102]

[0103]

[0104] Note: In Table 2, "-" indicates none.

[0105] Using Mn, Cr, Ni, Mo, and V as the main elements, the alloy is classified based on an alloy classification model.

[0106] Carbon (C) from the minor elements is taken as the target element. The operation space for C is reserved, and the carbon increase is adjusted to 0.05%, that is, the carbon content in the target composition of molten steel should be ≤0.18% (0.23-0.05=0.18). High chromium alloy, ferromolybdenum alloy, ferrovanadium alloy, high manganese alloy and nickel plate are determined as the first-level alloys. Based on the alloy input calculation model α1, the calculated first composition is obtained.

[0107] The statistical results of the calculated content of each element in the first component are shown in Table 3.

[0108] Table 3

[0109] Target ingredient ≤0.18 0.06 0.25 1.65 3.35 0.35 0.12 ≤0.05 First component 0.23 0.08 0.25 1.64 3.34 0.35 0.12 0.004

[0110] As shown in Table 3, neither Cr nor Ni met the requirements. Based on the difference between the contents of Mn, Cr, Ni, Mo, and V in the first component and the target component, high-chromium alloy and nickel plate were added, and a second calculation was performed to obtain the second component.

[0111] The statistical results of the calculated content of each element in the second component are shown in Table 4.

[0112] Table 4

[0113] Target ingredient ≤0.18 0.06 0.25 1.65 3.35 0.35 0.12 ≤0.05 Second component 0.23 0.08 0.25 1.65 3.35 0.35 0.12 0.004

[0114] As shown in Table 4, neither C nor Si met the requirements. Based on the difference between the C and Si content in the first component and the target component, the high-chromium alloy was reduced and the medium-chromium alloy was increased. A third calculation was performed to obtain the third component.

[0115] The statistical results of the calculated content of each element in the third component are shown in Table 5.

[0116] Table 5

[0117] Target ingredient ≤0.18 0.06 0.25 1.65 3.35 0.35 0.12 ≤0.05 Third component 0.18 0.066 0.25 1.65 3.35 0.35 0.12 -

[0118] As shown in Table 5, the content of each element in the third component meets the requirements of the target component.

[0119] In the process of calculating the first, second, and third components, the amount of each alloy added and reduced was statistically analyzed.

[0120] The results of the addition (t) and reduction (t) of each alloy are shown in Table 6.

[0121] Table 6

[0122] First component +0.135 +0.073 +1.210 * +0.107 +1.339 52.864 Second component * * +0.009 * * +0.005 52.878 Third component * * -0.440 +0.432 * * 52.856

[0123] Note: In Table 6, "*" indicates 0, meaning neither increase nor decrease; "+" indicates positive, meaning the amount of alloy added; and "-" indicates negative, meaning the amount decreased.

[0124] As shown in Table 6, the total amount of molten steel for the third component is 52.856t, which meets the requirement of 52.9t for molten steel in Table 4 with one decimal place, and satisfies the requirement of <53t. The addition amounts of ferromolybdenum alloy, ferrovanadium alloy, high chromium alloy, and medium chromium alloy obtained from the third calculation are sent to the alloy feeding system to smelt and obtain 25Cr2Ni4MoV high alloy steel.

[0125] Example 2

[0126] This embodiment takes refined 13Cr9Mo2Co3W2NNbB high alloy steel as an example. The initial molten steel volume is 64t, the target molten steel volume is 76t, the molten steel volume is retained to one decimal place, and the second decimal place is rounded off. The acceptable error for the target molten steel volume is ±0.1t. The alloy yield is considered to be 100% in the calculation.

[0127] The chemical composition requirements (mass percentage) for initial molten steel and target molten steel are shown in Table 5.

[0128] Table 7

[0129]

[0130] The alloy was calculated using Mn, Cr, Ni, Mo, V, W, and Co as the main elements.

[0131] Carbon (C) from the minor elements is taken as the target element, with reserved operating space for C. The carbon increase in slag adjustment is 0.06%, and the carbon content of the alloy after adjustment should be ≤0.06% (0.12-0.06=0.06). The types of ferrochrome alloys are determined as low-carbon ferrochrome alloy, ferromolybdenum alloy, ferrovanadium alloy, metallic manganese alloy (process requirements), ferrotungsten alloy, and electrolytic cobalt alloy (according to smelting common sense, high-carbon ferrochrome and medium-carbon ferrochrome are not used in smelting this steel grade), which are taken as the first alloy, and the first composition is calculated.

[0132] The statistical results of the alloy composition used in this embodiment are shown in Table 8.

[0133] Table 8

[0134]

[0135]

[0136] The statistical results of the calculated content of each element in the first component are shown in Table 9.

[0137] Table 9

[0138] Target ingredient 0.12 0.05 0.52 9.00 / 0.45 0.21 ≤0.01 2.10 3.00 First component 0.089 0.094 0.443 7.85 0.05 0.371 0.188 0.006 1.606 2.473

[0139] As shown in Table 8, the main elements Mn, Cr, Ni, Mo, and V did not meet the target lower limit requirements. Based on the difference between the content of the main elements that did not meet the target lower limit and the target middle limit, the second component was obtained by increasing the amount of low-carbon ferrochrome alloy, metallic manganese alloy, ferromolybdenum alloy, ferrovanadium alloy, ferrotungsten alloy, and electrolytic cobalt on the basis of the first component.

[0140] The statistical results of the calculated content of each element in the obtained second component are shown in Table 10.

[0141] Table 10

[0142]

[0143] As shown in Table 10, Mn, Mo, and V did not meet the target middle limit requirements, Cr and W did not meet the target lower limit requirements, and Ni exceeded the target upper limit. Based on the difference between the main elements that did not meet the requirements and the target middle limit, the amounts of low-carbon ferrochrome alloy, metallic manganese, ferromolybdenum alloy, and ferrotungsten alloy were increased to calculate the third component.

[0144] The statistical results of the calculated content of each element in the obtained third component are shown in Table 11.

[0145] Table 11

[0146]

[0147] As shown in Table 11, the main elements Mn, Cr, Ni, Mo, V, W and Co all meet the upper and lower limits of the target molten steel, but there are still differences from the target middle limit. Therefore, based on the third component, the amounts of low carbon ferrochrome, metallic manganese, ferrotungsten and electrolytic cobalt are increased to obtain the fourth component.

[0148] The statistical results of the calculated content of each element in the obtained fourth component are shown in Table 12.

[0149] Table 12

[0150]

[0151]

[0152] As shown in Table 12, Mn, Cr, Ni, Mo, V, W, and Co basically meet the requirements of the target middle limit or are not far from the target middle limit, but C and Si are much higher than the target upper limit. Based on the fourth component, it is necessary to reduce the amount of low carbon ferrochrome alloy and increase the amount of micro carbon ferrochrome to obtain the fifth component.

[0153] The statistical results of the calculated content of each element in the fifth component are shown in Table 13.

[0154] Table 13

[0155] Target ingredient 0.12 0.05 0.52 9.00 / 0.45 0.21 ≤0.01 2.10 3.00 Fifth component 0.062 0.149 0.52 9.00 0.048 0.447 0.21 0.006 2.10 3.00

[0156] As shown in Table 13, C, Mn, Cr, Mo, V, W, and Co all meet the requirements, while Si does not meet the target upper limit. Since the content of Si has other uses, it does not affect the process requirements for smelting and preparing 25Cr2Ni4MoV high alloy steel, so it is ignored here.

[0157] During the calculation process to obtain the first to fifth components, the amount of each alloy added and reduced was statistically analyzed.

[0158] The results of the addition (t) and reduction (t) of each alloy are shown in Table 14.

[0159] Table 14

[0160]

[0161] Note: In Table 14, "*" indicates 0, meaning neither increase nor decrease; "+" indicates positive, meaning the amount of alloy added; and "-" indicates negative, meaning the amount decreased.

[0162] As shown in Table 14, the total amount of molten steel is 80.760t, which is higher than the target amount of molten steel of 76t. It is necessary to reduce the initial amount of molten steel and the total amount of alloy. Since the ratio of the initial amount of molten steel to the total amount of alloy is 16.760:64, based on the target amount of molten steel of 76t, the initial amount of molten steel is reduced by 3.8t and the total amount of alloy is reduced by 0.96t. The corrected amount of the sixth component and each alloy is then recalculated.

[0163] The statistical results of the calculated content of each element in the sixth component are shown in Table 15.

[0164] Table 15

[0165] Target ingredient 0.12 0.05 0.52 9.00 / 0.45 0.21 ≤0.01 2.10 3.00 Sixth component 0.06 0.151 0.52 9.00 0.048 0.45 0.21 0.006 2.10 3.00

[0166] As shown in Table 15, C, Mn, Cr, Mo, V, W, and Co all meet the requirements.

[0167] The results of the corrected dosage of each alloy are shown in Table 16.

[0168] Table 16

[0169]

[0170] The results of Examples 1 and 2 show that by calculating the main elements and presetting the operating space of the target elements, and adjusting the amount of alloys of different grades, the present invention can accurately control the chemical composition content in alloy steel to be the same as the target limit, and can meet the accurate control of the chemical composition and molten steel quantity before smelting of different high alloy steels.

Claims

1. A method for precisely controlling the chemical composition and molten steel quantity of high alloy steel, characterized in that: The method is as follows: 1) Obtain the steel model parameters based on the steel grade being smelted, including the initial weight of the molten steel X 初 Initial composition of molten steel, target weight of molten steel X 目 ±x and the target composition of molten steel, and the control range of molten steel composition; where X 目 +x represents the upper limit of the target weight of molten steel, X 目 -x indicates the lower limit of the target weight of molten steel; 2) Obtain alloy grading parameters based on the target composition and initial composition of the molten steel obtained in step 1), including alloy price, main elements and content of the alloy, and minor elements and content of the alloy; 3) Based on the alloy grading parameters obtained in step 2), first consider the main elements of the alloy to group the alloys, then consider the content of minor elements in the alloy to grade the alloys in each group from high to low, and finally consider the price of the alloy to adjust the graded alloys from low to high, and establish an alloy grading model; input the alloy grading parameters into the alloy grading model, and output s grading levels of the alloy according to the alloy grading model, including the first grade alloy, the second grade alloy, ..., the (s-1)th grade alloy, and the sth grade alloy; 4) Based on the steel model parameters obtained in step 1), while considering the middle and upper limits of the target content of all main elements, select any element from the secondary elements as the target element, preset the operation space ψ+y of the target element content, and establish the alloy input calculation model α1. Input the first-level alloy and element content corresponding to the main element in step 3) into the alloy input amount calculation model α1, and output the input amount of each first-level alloy and the first composition of the molten steel according to the alloy input amount calculation model α1. If the calculated content of the target element in the first component is less than ψ + y, then there is a solution. Output the alloy input amount of each first-level alloy and proceed to step 7). Here, ψ represents the middle limit of the target element and ψ + y represents the upper limit of the operating space. If the calculated content of the target element is greater than ψ+y, then there is no solution. Output the calculated input of each first-level alloy, and output the calculation result of the first composition of the molten steel, then proceed to step 5). 5) Based on the difference ε between the target element content and the operating space ψ+y in the first composition calculation result of step 4), and the first-level alloy containing the first main element corresponding to the target element, while considering the mid-limit and upper-lower limit constraints of the target content of all main elements, consider the reduction of the first-level alloy corresponding to the difference ε, and the increase of the second-level alloy corresponding to the reduction of the first-level alloy of the first main element, and establish an alloy input calculation model α2; input the calculated input of the first-level alloy, the first composition calculation result, and the second-level alloy and element content corresponding to the first main element into the alloy input calculation model α2, and output the addition amount of each first-level alloy and second-level alloy and the second composition of the molten steel according to the alloy input calculation model α2; If the calculated content of the target element in the second component is less than ψ + y, then there is a solution. Output the input amounts of the first-level alloy and the second-level alloy, and proceed to step 7). If the calculated content of the target element in the second component is greater than ψ + y, then there is no solution. An inner loop is established based on the alloy input calculation model α2. If the calculated content of the target element is less than ψ + y after the inner loop increases to the t-th alloy, then there is a solution. Output the input of each alloy and the t-th component. Where 2 < t ≤ s. If, after the inner loop increases to the s-th alloy containing the first major element, the calculated content of the target element is greater than ψ + y, then there is no solution, and proceed to step 6). 6) Based on the difference ε between the target element and the operating space ψ in the first calculated component in step 4), and the first-level alloy containing the second principal element corresponding to the target element, while considering the middle and upper limits of the principal element target, we also consider the reduction of the first-level alloy containing the second principal element corresponding to the difference ε, and the increase of the second-level alloy containing the second principal element corresponding to the reduction of the first-level alloy, and establish the alloy input calculation model α3. Input the calculated input amount of the first-level alloy in step 4), the calculation result of the first component, and the second-level alloy containing the second main element and its element content into the alloy input amount calculation model α3. Output the input amount of each alloy and the calculated composition of the molten steel according to the alloy input amount calculation model α3. If the calculated content of the target element in the calculated composition of the molten steel is less than ψ + y, then there is a solution. Output the input amount of each alloy and proceed to step 7). If the calculated content of the target element is greater than ψ+y, there is no solution. An inner loop is established for the calculation model α3 based on the alloy input amount. If the content of the target element in the calculated composition of the molten steel is less than ψ+y after the inner loop increases to the u-th level alloy, there is a solution. The input amount of each alloy is output. Where u≤s. If, after the inner loop increases to the s-th level alloy containing the second principal element, the content of the target element in the calculated composition of the molten steel is greater than ψ+y, then there is no solution; confirm whether there is still an alloy containing the target element and the nth principal element. If so, establish an alloy input calculation model αn+1 to solve it; if not, consider relaxing the operation space ψ+y and return to step 4). Where 2 < n ≤ the number of all principal elements; 7) Based on the alloy input amounts in steps 4)-6), and considering the upper and lower limits of the target values ​​for all major and minor elements, establish an alloy composition calculation verification model; combine the alloy input amount, element content, and initial weight of molten steel X 初 1) Input the initial composition model parameters of molten steel into the alloy composition calculation and verification model. If the calculated content of all minor elements meets the target upper and lower limits, the verification has a solution, output the calculated total amount of molten steel, and proceed to step 8. 2) If the calculated content of any minor element is not within the target upper and lower limits, there is no solution. Locate the minor element, take it as the target element, and return to step 4. 8) The total amount of molten steel output in step 7) must satisfy the target weight of molten steel X. 目 If the requirement is ±x, then the initial weight of the molten steel is X. 初 The results of the alloy input amount are transmitted to the alloy feeding system for smelting. If the calculated total amount of molten steel J does not meet the target weight X of molten steel 目 If ±x is required, then the total calculated amount of molten steel is compared with the target weight X of the molten steel. 目 weight difference ε 重 According to the initial weight of molten steel X 初 The weight ratio of the molten steel and alloy is adjusted according to the weight of the alloy input, and the corresponding weight of the molten steel and alloy is transmitted to the alloy feeding system for smelting.

2. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Step 3), grouping the alloys based on their main elements, specifically: When an alloy contains a main element, the main element is used as the grouping criterion, and alloys containing the main element are selected as a group. When an alloy contains two or more main elements, the alloy is classified into groups for each main element.

3. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 2, characterized in that: Step 3), classifying the alloys within each group based on the content of minor elements from high to low, specifically: Based on the grouping of each main element, a table of secondary element content is established for each group. Based on the minor elements, the content table of each minor element is filtered level by level to obtain the alloy sorting order results corresponding to the content of each minor element from high to low. If the alloy sorting order results of all minor elements are the same, the alloy sorting order results are merged and output. If any two or more alloy sorting order results are the same, the same alloy sorting order results are merged and output, and the sorting order results of other alloys are also output. The alloys are classified according to their sorting order, and the classification result parameters are output, including the main element, minor element, and alloy classification level.

4. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 3, characterized in that: The classification of alloys within each group based on the content of minor elements from high to low also includes verification of alloys in different groups, the verification including: Check if the same alloy exists in all groups. If so, locate the alloy classification level of the same alloy in each group. Retain the same alloys in the higher alloy classification group, delete the same alloys in other groups, and re-output the classification result parameters according to the sorting order in each group.

5. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Step 3), the number of the s grade levels is less than or equal to the number of alloys in each group.

6. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Steps 4)-6) In the alloy input calculation model α1~αn+1, the alloy input is calculated based on the difference between the content of major elements in the initial composition of molten steel and the middle limit of the content of major elements in the target composition of molten steel. The content of minor elements is calculated based on the input of each alloy.

7. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Step 5): If the reduction of the first-level alloy containing the first main element is less than the amount of the first-level alloy added, then the increase of the second-level alloy containing the first main element is calculated based on the amount of the first-level alloy added.

8. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Step 6): If the reduction of the first-level alloy containing the second main element is less than the amount of the first-level alloy added, then the increase of the second-level alloy containing the second main element is calculated based on the amount of the first-level alloy added.

9. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: The high-alloy steel is a type of steel in which the total amount of alloy added is greater than 5% of the initial molten steel.

10. The method for precisely controlling the chemical composition and molten steel quantity of high-alloy steel according to claim 1, characterized in that: Step 8), specifically reducing or increasing the corresponding weight of molten steel and alloy, involves: When ε 重 When x > 0, reduce the corresponding weight of molten steel and alloy by weight ratio; When ε 重 When -x < 0, increase the weight of molten steel and alloy by weight ratio.

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