A method for adjusting the length of a bloom

Abstract

The present application relates to the technical field of steelmaking continuous casting, and particularly relates to a method for adjusting the length of square billets, which comprises the following steps: defining the hot billet density, the theoretical cross-sectional area of the billet and the theoretical standard weight of the billet; obtaining the actual weight of the billet by weighing; obtaining the actual length of the billet by measuring the hot billet; calculating the adjustment amount of the billet and the weight difference ratio according to the theoretical standard weight of the billet and the actual weight of the billet; and calculating the length of the next billet according to the correction coefficient, the adjustment amount of the billet and the actual length of the previous billet. The present application realizes the purpose of controlling the weight difference of the billet within 3‰.

Description

Technical Field

[0001] This invention relates to the field of steelmaking continuous casting technology, and in particular to a method for adjusting the length of a square billet. Background Technology

[0002] In the continuous casting production of billets, infrared calibration or calculation calibration methods are usually used to cut the hot billets. The cutting length is usually obtained by experience. However, due to the influence of many factors such as casting speed and superheat, there is a certain error in the length of the billet, that is, the actual weight of the billet deviates from the standard weight.

[0003] When using continuously cast billets to produce bars, the billets are cut according to length, but the rolled product is rolled according to weight. Therefore, the stability of the billet weight is crucial to the final product yield. When the billet weight deviates from the standard weight, the rolled product will have short or long sections, which must be recycled as scrap, resulting in waste. However, if the weight difference between the actual billet weight and the standard weight is controlled within 3‰, the short or long sections can be reduced, thereby improving the final product yield. Based on a selling price of 4000-6000 yuan per ton, every 1% increase in yield can reduce the cost per ton of steel by 40-60 yuan, making a significant contribution to cost reduction and efficiency improvement for steel mills.

[0004] Steel mills typically use a flow-by-flow weighing method, adjusting the length of each flow based on the weighing results. We define the billet weight difference ratio as (actual billet weight - standard weight) / standard weight. A ratio within 3‰ indicates the billet weight is within a good weight range, significantly improving the yield of rolled products. However, in reality, steel mill weighing equipment usually has an error range of 5‰. Weighing equipment with an error range of 5‰ is needed to obtain a result with a standard deviation of 3‰. If adjustments are made based solely on the difference between the actual and standard weights, ignoring the weighing error, it usually results in a larger deviation between the actual and standard weights. Summary of the Invention

[0005] To address the shortcomings of existing algorithms, this invention provides a method for adjusting the length of a cast billet, thereby controlling the weight difference of the cast billet to within 3‰.

[0006] The technical solution adopted in this invention is: a method for adjusting the length of a square billet includes the following steps:

[0007] Step 1: Define the hot billet density, theoretical cross-sectional area, and theoretical standard weight of the billet;

[0008] Furthermore, the density of the hot billet is defined as ρ = 7.4-7.9 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0 - 0.4 m². 2The theoretical standard weight of the billet is Mb, and the unit is t. The theoretical standard weight of the billet can be obtained by measuring the weight and length of multiple room temperature billets.

[0009] Step 2: Obtain the actual weight of the cast billet by weighing;

[0010] Weighing equipment with different levels of precision has different prices; the higher the precision, the higher the price. The actual weight of the cast billet is Ms, in tons.

[0011] Step 3: Obtain the actual length of the cast billet by measuring the hot billet;

[0012] The actual length L of the hot billet after cutting s The unit is meters (m). This L s That is, if there is a deviation in the weight of the cast billet given by the system, the given length value needs to be corrected.

[0013] Step 4: Calculate the billet adjustment amount and weight difference ratio based on the theoretical standard weight of the billet and the actual billet weight;

[0014] The further adjustment amount ΔL for the cast billet is given by the formula:

[0015]

[0016] Where Mb is the theoretical standard weight of the billet, and Ms is the actual weight of the billet;

[0017] Furthermore, the weight difference ratio ΔM is calculated using the following formula:

[0018] Step 5: Calculate the length of the next billet based on the correction factor, billet adjustment amount, and the actual length of the previous billet;

[0019] Furthermore, the formula for the next billet length is:

[0020] L′ S =L s +k*ΔL

[0021] Among them, L s ΔL is the actual length of the previous billet, k is the correction coefficient, and ΔL is the billet adjustment amount.

[0022] Furthermore, based on the range of the weight difference ratio, a correction factor is set, according to the following rules:

[0023] If 0 ≤ ΔM < 0.05%, the correction factor is 0 ≤ k < 0.05;

[0024] If 0.05% ≤ ΔM < 0.3%, the correction factor is 0.05 ≤ k < 0.3;

[0025] If 0.3% ≤ ΔM < 0.5%, the correction factor should be 0.3 ≤ k < 0.5.

[0026] If 0.5% ≤ ΔM < 1%, the correction factor should be 0.5 ≤ k < 0.7.

[0027] If 1% ≤ ΔM < 1.5%, the correction factor should be 0.7 ≤ k < 0.9;

[0028] If ΔM ≥ 1.5%, the length of the cast billet needs to be reset to the empirical length or the billet needs to be weighed again.

[0029] Since the weighing equipment has an error of 5‰, the actual weight Ms after weighing will also have a certain error. Therefore, if the adjustment is made exactly according to ΔL, it may result in an incorrect actual length L′ for the next casting. S If the weight is too long or too short, the adjusted weight will deviate significantly from the standard weight. Therefore, it is necessary to adjust the coefficient of ΔL according to the difference between the actual weight Ms and the standard weight Mb.

[0030] The beneficial effects of this invention are:

[0031] 1. Control the error between the corrected billet weight and the weighing within the standard range of 3‰.

[0032] 2. This method is simple, convenient, and easy to operate. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method for adjusting the length of the billet according to the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. The drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0035] After the billet is cast, a length is given based on experience. After a period of stable cutting, the billet is usually weighed. The weight is compared with the standard billet weight. If it is less than the standard weight, the length is increased; if it is greater than the standard weight, the length is decreased. This makes the billet closer to the standard weight, thus reducing the waste of rolled material.

[0036] If the weighing equipment has no error, adjustments can be made according to the direct calculation formula. However, in practice, it is often found that the weight of the cast billet deviates more significantly after adjustment, which is related to the error of the weighing equipment.

[0037] Since the error of typical weighing equipment is within 5‰ and the standard deviation of billet weight is within 3‰, if adjustments are made directly based on the weighing results, the weighing error will cause the adjustment data to be too large, thus making the actual billet weight deviate further from the standard weight. Therefore, it is necessary to correct the billet length adjustment.

[0038] like Figure 1 As shown, a method for adjusting the length of a billet includes the following steps:

[0039] Example 1:

[0040] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0041] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.813t; the actual length L of the hot billet was measured. s =10.17m;

[0042] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0043]

[0044] The weight difference ratio ΔM is defined by the following formula:

[0045] Since 1% ≤ ΔM < 1.5% at this point, the correction factor is k = 0.8;

[0046] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.08m.

[0047] The adjusted billet was weighed again, and its actual weight was 4.774t.

[0048] Example 2:

[0049] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0050] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.805t; the actual length L of the hot billet was measured. s =10.13m;

[0051] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0052]

[0053] The weight difference ratio ΔM is defined by the following formula:

[0054] Since 0.5% ≤ ΔM < 1% at this point, the correction factor is taken as k = 0.6;

[0055] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.07m.

[0056] The adjusted billet was weighed again, and its actual weight was 4.769t.

[0057] Example 3:

[0058] First, define the density of the hot billet as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0059] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.738t; the actual length L of the hot billet was measured. s =10.05m;

[0060] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0061]

[0062] The weight difference ratio ΔM is defined by the following formula:

[0063] Since 0.3% ≤ ΔM < 0.5% at this point, the correction factor is k = 0.3;

[0064] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.06m.

[0065] The adjusted billet was weighed again, and its actual weight was 4.765t.

[0066] Example 4:

[0067] First, define the density of the hot billet as ρ = 7.8 t / m³.3 The theoretical cross-sectional area of ​​the cast billet is S = 0.058 m². 2 ;

[0068] The theoretical standard weight of the cast billet is Mb = 4.55t; the actual weight of the cast billet obtained by weighing is Ms = 4.510t; the actual length L of the hot billet was measured. s =10.00m;

[0069] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0070]

[0071] The weight difference ratio ΔM is defined by the following formula:

[0072] Since 0.5% ≤ ΔM < 1% at this point, the correction factor is k = 0.5;

[0073] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.04m.

[0074] The adjusted billet was weighed again, and its actual weight was 4.540t.

[0075] Example 5:

[0076] First, define the density of the hot billet as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.058 m². 2 ;

[0077] The theoretical standard weight of the cast billet is Mb = 4.55t; the actual weight of the cast billet obtained by weighing is Ms = 4.571t; the actual length L of the hot billet was measured. s =10.08m;

[0078] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0079]

[0080] The weight difference ratio ΔM is defined by the following formula:

[0081] Since 0.3% ≤ ΔM < 0.5% at this point, the correction factor is k = 0.4;

[0082] The adjusted billet length L′ S The following formula exists: L′S =L s +k*ΔL=10.06m.

[0083] The adjusted billet was weighed again, and its actual weight was 4.560t.

[0084] Example 6:

[0085] First, define the density of the hot billet as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.058 m². 2 ;

[0086] The theoretical standard weight of the cast billet is Mb = 4.55t; the actual weight of the cast billet obtained by weighing is Ms = 4.607t; the actual length L of the hot billet was measured. s =10.15m;

[0087] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0088]

[0089] The weight difference ratio ΔM is defined by the following formula:

[0090] Since 1% ≤ ΔM < 1.5% at this point, the correction factor is k = 0.7;

[0091] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.06m.

[0092] The adjusted billet was weighed again, and its actual weight was 4.563t.

[0093] Example 7:

[0094] First, define the density of the hot billet as ρ = 7.835 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0095] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.735t; the actual length L of the hot billet was measured. s =9.99m;

[0096] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0097]

[0098] The weight difference ratio ΔM is defined by the following formula:

[0099] Since 0.5% ≤ ΔM < 1% at this point, the correction factor is taken as k = 0.6;

[0100] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.02m.

[0101] The adjusted billet was weighed again, and its actual weight was 4.748t.

[0102] Example 8:

[0103] First, define the density of the hot billet as ρ = 7.835 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0104] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.779t; the actual length L of the hot billet was measured. s =10.04m;

[0105] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0106]

[0107] The weight difference ratio ΔM is defined by the following formula:

[0108] Since 0.3% ≤ ΔM < 0.5% at this point, the correction factor is k = 0.4;

[0109] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.02m.

[0110] The adjusted billet was weighed again, and its actual weight was 4.750t.

[0111] Example 9:

[0112] First, define the density of the hot billet as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.025 m². 2 ;

[0113] The theoretical standard weight of the cast billet is Mb = 1.99t; the actual weight of the cast billet obtained by weighing is Ms = 1.976t; the actual length L of the hot billet was measured. s =9.98m;

[0114] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0115]

[0116] The weight difference ratio ΔM is defined by the following formula:

[0117] Since 0.5% ≤ ΔM < 1% at this point, the correction factor is taken as k = 0.6;

[0118] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.02m.

[0119] The adjusted billet was weighed again, and its actual weight was 1.988t.

[0120] Example 10:

[0121] First, define the density of the hot billet as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.025 m². 2 ;

[0122] The theoretical standard weight of the cast billet is Mb = 1.99t; the actual weight of the cast billet obtained by weighing is Ms = 1.997t; the actual length L of the hot billet was measured. s =10.04m;

[0123] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0124]

[0125] The weight difference ratio ΔM is defined by the following formula:

[0126] Since 0.3% ≤ ΔM < 0.5% at this point, the correction factor is k = 0.4;

[0127] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.03m.

[0128] The adjusted billet was weighed again, and its actual weight was 1.990t.

[0129] Example 11:

[0130] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0131] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.760t; the actual length L of the hot billet was measured. s =10.07m;

[0132] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0133]

[0134] The weight difference ratio ΔM is defined by the following formula:

[0135] Since 0 ≤ ΔM < 0.05% at this point, the correction factor is k = 0.0;

[0136] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.07m.

[0137] The adjusted billet was weighed again, and its actual weight was 4.760t.

[0138] Example 12:

[0139] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0140] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.762t; the actual length L of the hot billet was measured. s =10.07m;

[0141] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0142]

[0143] The weight difference ratio ΔM is defined by the following formula:

[0144] Since 0 ≤ ΔM < 0.05% at this point, the correction factor is k = 0.045;

[0145] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.07m.

[0146] The adjusted billet was weighed again, and its actual weight was 4.756t.

[0147] Example 13:

[0148] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0149] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.770t; the actual length L of the hot billet was measured. s =10.08m;

[0150] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0151]

[0152] The weight difference ratio ΔM is defined by the following formula:

[0153] Since 0.05% ≤ ΔM < 0.3% at this point, the correction factor is k = 0.05;

[0154] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.08m.

[0155] The adjusted billet was weighed again, and its actual weight was 4.766t.

[0156] Example 14:

[0157] The density of the hot billet is defined as ρ = 7.8 t / m³. 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.061 m². 2 ;

[0158] The theoretical standard weight of the cast billet is Mb = 4.760t; the actual weight of the cast billet obtained by weighing is Ms = 4.828t; the actual length L of the hot billet was measured. s =10.17m;

[0159] Based on the difference between the actual weight Ms and the standard weight Mb, the actual adjustment amount ΔL that needs to be adjusted can be calculated, and the formula is as follows:

[0160]

[0161] The weight difference ratio ΔM is defined by the following formula:

[0162] Since 1% ≤ ΔM < 1.5% at this point, the correction factor is k = 0.88;

[0163] The adjusted billet length L′ S The following formula exists: L′ S =L s +k*ΔL=10.04m.

[0164] The adjusted billet was weighed again, and its actual weight was 4.746t.

[0165] According to the method of the present invention, after the cast billet is cut, its weight is compared with the standard weight. More than 95% of the cast billets weigh within the standard range of 3‰.

[0166] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for adjusting the length of a square billet, characterized in that, Includes the following steps: Step 1: Define the hot billet density of the cast billet. Theoretical cross-sectional area of ​​the cast billet and the theoretical standard weight of the cast billet (Mb); Step 2: Obtain the actual weight Ms of the cast billet by weighing; Step 3: Obtain the actual length of the cast billet by measuring the hot billet; Step 4: Calculate the billet adjustment amount and weight difference ratio based on the theoretical standard weight of the billet and the actual billet weight; The formula for the weight difference ratio is: Step 5: Calculate the length of the next billet based on the correction factor, billet adjustment amount, and the actual length of the previous billet; The formula for calculating the length of the next casting billet is: Among them, L s ΔL is the actual length of the previous billet, k is the correction coefficient, and ΔL is the billet adjustment amount. The relationship between the weight difference ratio and the correction factor is as follows: if The correction factor is taken as: ; if The correction factor is taken as: ; if The correction factor is taken as: ; if The correction factor is taken as: ; if The correction factor is taken as: .

2. The method for adjusting the length of a square billet according to claim 1, characterized in that, The density of the hot billet is ρ = 7.4-7.9 t / m³ 3 The theoretical cross-sectional area of ​​the cast billet is S = 0.025 - 0.4 m². 2 .

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