Accurate control method for steel converter tapping alloying of rail steel

Abstract

The invention discloses an accurate control method for steel converter tapping alloying of rail steel, alloys are added for alloying in the converter smelting tapping process, and the addition amount of each alloy is calculated according to the absorptivity of the element E in the alloy calculated by the following formula (I). According to the method, the absorptivity of the elements is accurately calculated by creatively analyzing the influence factors of the alloy elements, so that the alloying accurate control capability in the converter tapping process is fundamentally improved, and a basis is provided for subsequent smelting. The method can achieve the purpose of improving the internal cleanliness of the steel rail, can be applied to the steelmaking process on a large scale, and is easy and convenient to operate and stable in effect. Compared with a traditional steelmaking process, the method can effectively consider converter smelting alloying cost and quality control, and the product quality and social and economic benefits are improved.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, in particular to an accurate control method for alloying of rail steel converter tapping. Background Art

[0002] In recent years, with the implementation of the national railway power strategy, high speed and heavy load are becoming two trends in the development of the railway industry. As rails are responsible for facilitating people's travel and cargo transportation, the quality requirements for them are not too stringent. As the main load-bearing component of the train, the quality will directly affect the safe operation of the train. In the actual production process of rails, in addition to high quality requirements, companies also need to take into account production costs. In the smelting process, the importance of the converter as the leader of steelmaking production cost and quality control is self-evident. Converter steel alloying is the first step in the production of high-quality rails, and is also closely related to cost control. Therefore, how to achieve low cost and high quality of converter steel alloying is a common technical problem in the industry.

[0003] In the prior art, patent application CN202410613377.8 provides a method for calculating alloy ingredients in converter blowing, which includes: collecting various data of converter smelting, and then calculating the amount of alloy added according to the target steel grade; but this method does not involve the problem of accurately calculating the absorption rate. Patent application CN202410341698.7 provides a multi-mode charging method for the converter steelmaking process based on the ferroalloy grading system. This method is mainly based on the "differential" idea in mathematics, and classifies alloy ferroalloys with large composition fluctuations to reduce alloy costs, but it also does not involve the problem of accurately calculating the alloy absorption rate. The above two methods are both aimed at alloying in the converter steelmaking process, and are achieved by optimizing or strengthening certain process parameters, but neither has made a substantial breakthrough. On the whole, the above two methods are not the best choices. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an accurate control method for alloying of rail steel converter tapping, so as to achieve optimization of alloy ratio and cost control.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: alloys are added to the converter during steelmaking for alloying, and the amount of each alloy added is calculated according to the absorption rate of element E in the alloy calculated by the following formula (I);

[0006]

[0007] Among them, C loss – Loss of C element during converter steelmaking, %; C conv – Carbon content of converter steel, %; – Corrected value of carbon content, %; – Balance parameters; – Balance parameters related to carbon and oxygen content in molten steel; – Maximum absorption rate of element E in the alloy, %; Y E –Absorption rate of element E in the alloy, %.

[0008] Furthermore, the The following (II) is used for calculation;

[0009]

[0010] in, – The influence coefficient of bottom blowing and stirring on the absorption rate of element E; – is the general influence coefficient of bottom blowing stirring alloy, which can be taken as 0.7 to 1.0 according to the bottom blowing intensity; –The effect coefficient of decarburization on the absorption rate of element E.

[0011] Furthermore, the element E is C, Si or Mn.

[0012] Furthermore, when the element E is C, The value is 0.011. The value is -15. The value is 0.005. The value is -0.5; the maximum absorption rate of element C Calculated at 78% to 80%;

[0013] When the element E is Mn, The value is 0.013. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Mn Calculated at 93% to 95%;

[0014] When the element E is Si, The value is 0.018. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Si Calculated based on 90% to 92%.

[0015] Furthermore, the C element loss amount C during the converter steel tapping process is loss The value is determined according to the different C content at the end point: When the C content at the converter end point is ≤0.10%, C loss Take 0.025%; when the C content at the converter end point is between 0.10% and 0.20%, C lossTake 0.035%; when the C content of the converter end point is ≥ 0.20%, C loss Take 0.042%.

[0016] The beneficial effect of adopting the above technical scheme is that compared with the traditional process of estimating the absorption rate of rail smelting alloy, the present invention takes a unique approach and creatively analyzes the influencing factors of alloy elements to accurately calculate the absorption rate of elements, fundamentally improving the ability to accurately control alloying in the converter steelmaking process and providing a basis for subsequent smelting.

[0017] The present invention can achieve the purpose of improving the internal cleanliness of the rail, can be applied in the steelmaking process on a large scale, is easy to operate and has a stable effect. Compared with the traditional steelmaking process, the present invention can effectively take into account the converter smelting alloying cost and quality control, and improve the quality of the product and the social and economic benefits. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with specific implementation modes.

[0019] The steelmaking process of the rail steel converter is relatively complicated. In the actual production process, the absorption rate of each element of the alloy fluctuates greatly during the steelmaking process, affected by factors such as the final carbon content, oxygen content, bottom blowing intensity and steel production. In traditional smelting, empirical methods or ex post remedial methods are used for control, but the effect is relatively poor. On the one hand, the deviation in composition control affects the stability of the production efficiency of the subsequent processes. On the other hand, the deviation in composition control may lead to the generation of scrap and cause a large quality loss.

[0020] In order to further improve the internal cleanliness of the rails, the project team of this method conducted a large number of experimental studies. By comparing and analyzing the shortcomings of traditional smelting processes, they pioneered a new method for calculating the absorption rate of alloy elements and achieved precise control of alloying.

[0021] The traditional process is as follows: Rail steel is silicon-manganese deoxidized steel. During the steelmaking process in the converter, the absorption rate of a certain element E is Y E , traditional smelting is calculated by the following formula (A) and formula (B);

[0022]

[0023] Among them, Y E – Absorption rate of a certain element E during converter steelmaking, %; W bath – weight of molten steel in the ladle, i.e., the amount of steel tapped from the converter, t; ΔE – increase in element E (including loss during tapping), %; W E – the amount of an element E added during the converter steelmaking process, t; –Mass percentage of E element in the alloy, %; –The amount of alloy added to the ladle, that is, the amount of a certain alloy added to the ladle, t.

[0024] According to the above-mentioned traditional process for calculating the absorption rate of the E element in the alloy, the amount of alloy added needs to be known in advance, which obviously cannot be accurately predicted before steelmaking. In the traditional steelmaking process, the amount of alloy added is estimated more based on the operator's experience data, or the empirical value of the absorption rate of a certain element in the alloy. The result of this is that after the final alloying, the actual value of each element in the molten steel deviates greatly from the target value. When the actual value exceeds the target value, it may cause the finished product composition to exceed the standard, and then the corresponding ingot will be scrapped or returned to the furnace; when the actual value is lower than the target value, it will cause great pressure on the subsequent refining process. Therefore, how to accurately predict the absorption rate of each element in the alloy, and then accurately calculate the amount of alloy added to achieve precise control of the molten steel composition, is a common technical problem in the industry.

[0025] The accurate control method of the alloying of the steel rail steel converter tapping is based on a large number of production site test data. Through theoretical analysis and combined with the actual site, the relevant process parameters such as oxygen content, carbon content change, bottom blowing and stirring, which are closely related to the element absorption rate in the alloy, are used. According to the influence and change law of different elements, the following process is innovatively designed: alloys are added during the converter smelting and tapping process for alloying, and the addition amount of each alloy is calculated according to the absorption rate of the element E in the alloy calculated by the following formula (Ⅰ);

[0026]

[0027] Among them, C loss – Loss of C element during converter steelmaking, wt%; C conv – Carbon content of molten steel before alloying in converter, wt%; – Corrected value of carbon content, wt%; – Balance parameters; – Balance parameters related to carbon and oxygen content in molten steel; – Maximum absorption rate of element E in the alloy, %; Y E – Absorption rate of element E in the alloy, %;

[0028] Said The following (II) is used for calculation;

[0029]

[0030] in, – The influence coefficient of bottom blowing and stirring on the absorption rate of element E; – is the general influence coefficient of bottom blowing stirring alloy, which can be taken as 0.7 to 1.0 according to the bottom blowing intensity; –The effect coefficient of decarburization on the absorption rate of element E.

[0031] During the steel-making process, the absorption rate of the elements in the alloy is closely related to the oxygen content in the molten steel. The above formula is applicable to C, Si, Mn and Al elements with high affinity to oxygen. However, rail steel is deoxidized by silicon manganese, and aluminum is not allowed to be added during steel-making or refining and slag-making. Therefore, for rail steel, only the absorption rates of C, Si and Mn are calculated:

[0032] When the element E is C, The value is 0.011. The value is -15. The value is 0.005. The value is -0.5; the maximum absorption rate of element C Calculated at 78% to 80%;

[0033] When the element E is Mn, The value is 0.013. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Mn Calculated at 93% to 95%;

[0034] When the element E is Si, The value is 0.018. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Si Calculated based on 90% to 92%.

[0035] The amount of C element loss during the converter steel tapping process C loss C is the carbon content of molten steel in converter conv Carbon content C of molten steel in ladle ladle The difference, C loss =C conv -C ladle ; According to the end point C content, the C element loss C loss Different values ​​are: When the C content at the converter end is ≤0.10wt%, C loss Take 0.025wt%; when the C content at the converter end is 0.10wt% to 0.20wt%, C loss Take 0.035wt%; when the C content at the converter end is ≥0.20wt%, C loss Take 0.042wt%.

[0036] Embodiment 1:

[0037] (1) In a top and bottom combined blowing converter, the steel grade smelted is U71Mn rail steel, the C content at the converter end point is 0.10%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.025%, the maximum absorption rate of the C element is calculated as 78%, the maximum absorption rate of the Mn element is calculated as 93%, and the maximum absorption rate of the Si element is calculated as 90%. According to formulas (Ⅰ) and (Ⅱ), the absorption rates of the C element, Mn element and Si element in the final alloying process are 72.79%, 87.63% and 82.81%, respectively. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 1; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 2;

[0038] Table 1: Calculation process parameters

[0039]

[0040] In Table 1, the corresponding relationship between each parameter and the symbols in formula (Ⅰ) and (Ⅱ): the alloy absorption rate is The maximum absorption rate is C conv -C o e is PCOe is CC e BS e The general effect of bottom blowing is PDCe Carbon loss is C loss .

[0041] Table 2: Actual absorption rate of each element

[0042]

[0043] In Table 2, the unit of dosage (added amount) is kg.

[0044] (2) After alloying, the composition of the ladle is C 0.70%, Si 0.40%, Mn 0.95%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 135 tons, the amount of carbon powder alloy added is 1135kg, the C content in the carbon powder is 98.5%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.60%; the amount of ferrosilicon alloy added is 895kg, the Si content in ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.40%; the amount of ferromanganese alloy added is 1990kg, the Mn content in ferromanganese is 69.8%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.90%; the calculation results show that the absorption rate of C element is 72.45%, the absorption rate of Mn element is 87.47%, and the absorption rate of Si element is 82.65%.

[0045] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0046] Embodiment 2:

[0047] (1) In a top and bottom combined blowing converter, the steel grade smelted is U75V rail steel, the C content at the converter end point is 0.15%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.035%, the maximum absorption rate of the C element is calculated as 79%, the maximum absorption rate of the Mn element is calculated as 94%, and the maximum absorption rate of the Si element is calculated as 91%. According to formulas (Ⅰ) and (Ⅱ), the absorption rates of the C element, the Mn element, and the Si element in the final alloying process are 75.94%, 91.16%, and 87.01%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 3; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 4;

[0048] Table 3: Calculation process parameters

[0049]

[0050] Table 4: Actual absorption rate of each element

[0051]

[0052] In Table 4, the unit of dosage (amount added) is kg.

[0053] (2) After alloying, the composition of the ladle is C 0.70%, Si 0.60%, Mn 0.87%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapped is 132 tons, the amount of carbon powder alloy added is 975kg, the C content in the carbon powder is 98.1%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.55%; the amount of ferrosilicon alloy added is 1240kg, the Si content in the ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.60%; the amount of ferromanganese alloy added is 1655kg, the Mn content in the ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.80%; the calculation results show that the absorption rate of C element is 75.9%, the absorption rate of Mn element is 91.8%, and the absorption rate of Si element is 87.26%.

[0054] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0055] Embodiment 3:

[0056] (1) In a top and bottom combined blowing converter, the steel grade smelted is U71Mn rail steel, the C content at the converter end point is 0.25%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.042%, the maximum absorption rate of the C element is calculated as 80%, the maximum absorption rate of the Mn element is calculated as 95%, and the maximum absorption rate of the Si element is calculated as 92%. According to formulas (Ⅰ) and (Ⅱ), the absorption rates of the C element, the Mn element, and the Si element in the final alloying process are 78.73%, 94.32%, and 90.80%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 5; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 6;

[0057] Table 5: Calculation process parameters

[0058]

[0059] Table 6: Actual absorption rate of each element

[0060]

[0061] In Table 6, the unit of dosage (amount added) is kg.

[0062] (2) After alloying, the composition of the ladle is C 0.70%, Si 0.38%, Mn 0.99%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 132 tons, the amount of carbon powder alloy added is 770kg, the C content in the carbon powder is 98.1%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.45%; the amount of ferrosilicon alloy added is 760kg, the Si content in ferrosilicon is 72.6%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.38%; the amount of ferromanganese alloy added is 1850kg, the Mn content in ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.92%; the calculation results show that: the absorption rate of C element is 78.63%, the absorption rate of Mn element is 94.45%, and the absorption rate of Si element is 90.91%.

[0063] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0064] Embodiment 4:

[0065] (1) In a top and bottom combined blowing converter, the steel grade smelted is U71Mn rail steel, the C content at the converter end point is 0.06%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.025%, the maximum absorption rate of the C element is calculated as 78%, the maximum absorption rate of the Mn element is calculated as 93%, and the maximum absorption rate of the Si element is calculated as 90%. According to formulas (Ⅰ) and (Ⅱ), the absorption rate of the C element in the final alloying process is 69.26%, the absorption rate of the Mn element is 84.12%, and the absorption rate of the Si element is 78.4%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 7; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 8;

[0066] Table 7: Calculation process parameters

[0067]

[0068] Table 8: Actual absorption rate of each element

[0069]

[0070] In Table 8, the unit of dosage (amount added) is kg.

[0071] (2) After alloying, the composition of the ladle is C 0.71%, Si 0.42%, Mn 0.98%, according to formula (A) and (B) to calculate the actual absorption rate of each element, wherein the amount of molten steel tapping is 131 tons, the amount of carbon powder alloy added is 1250kg, the C content in the carbon powder is 98.3%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.65%; the amount of ferrosilicon alloy added is 960kg, the Si content in ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.42%; the amount of ferromanganese alloy added is 2060kg, the Mn content in ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.92%; the calculation results show that: the absorption rate of C element is 69.29%, the absorption rate of Mn element is 84.18%, and the absorption rate of Si element is 78.51%.

[0072] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0073] Embodiment 5:

[0074] (1) In a top and bottom combined blowing converter, the steel grade smelted is U75V rail steel, the C content at the converter end point is 0.18%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.035%, the maximum absorption rate of the C element is calculated as 79%, the maximum absorption rate of the Mn element is calculated as 94%, and the maximum absorption rate of the Si element is calculated as 91%. According to formulas (Ⅰ) and (Ⅱ), the absorption rate of the C element in the final alloying process is 76.52%, the absorption rate of the Mn element is 91.73%, and the absorption rate of the Si element is 87.75%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 9; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 10;

[0075] Table 9: Calculation process parameters

[0076]

[0077] Table 10: Actual absorption rate of each element

[0078]

[0079] In Table 10, the unit of dosage (added amount) is kg.

[0080] (2) After alloying, the composition of the ladle is C 0.70%, Si 0.58%, Mn 0.85%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 132 tons, the amount of carbon powder alloy added is 915kg, the C content in the carbon powder is 98.3%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.52%; the amount of ferrosilicon alloy added is 1195kg, the Si content in ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.58%; the amount of ferromanganese alloy added is 1620kg, the Mn content in ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.78%; the calculation results show that: the absorption rate of C element is 76.31%, the absorption rate of Mn element is 91.45%, and the absorption rate of Si element is 87.52%.

[0081] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0082] Embodiment 6:

[0083] (1) In a top and bottom combined blowing converter, the steel grade smelted is U71Mn rail steel, the C content at the converter end point is 0.22%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.042%, the maximum absorption rate of the C element is calculated as 80%, the maximum absorption rate of the Mn element is calculated as 95%, and the maximum absorption rate of the Si element is calculated as 92%. According to formulas (Ⅰ) and (Ⅱ), the absorption rates of the C element, the Mn element, and the Si element in the final alloying process are 78.49%, 94.12%, and 90.54%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 11; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 12;

[0084] Table 11: Calculation process parameters

[0085]

[0086] Table 12: Actual absorption rate of each element

[0087]

[0088] In Table 12, the unit of dosage (amount added) is kg.

[0089] (2) After alloying, the composition of the ladle is C 0.68%, Si 0.38%, Mn 0.90%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 130 tons, the amount of carbon powder alloy added is 770kg, the C content in the carbon powder is 98.6%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.46%; the amount of ferrosilicon alloy added is 755kg, the Si content in ferrosilicon is 2.6%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.38%; the amount of ferromanganese alloy added is 1690kg, the Mn content in ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.85%; the calculation results show that the absorption rate of C element is 78.76%, the absorption rate of Mn element is 94.08%, and the absorption rate of Si element is 90.12%.

[0090] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0091] Embodiment 7:

[0092] (1) In a top and bottom combined blowing converter, the steel grade smelted is U75V rail steel, the C content at the converter end point is 0.05%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.025%, the maximum absorption rate of the C element is calculated as 78%, the maximum absorption rate of the Mn element is calculated as 93%, and the maximum absorption rate of the Si element is calculated as 90%. According to formulas (Ⅰ) and (Ⅱ), the absorption rate of the C element in the final alloying process is 68.25%, the absorption rate of the Mn element is 83.83%, and the absorption rate of the Si element is 78.17%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 13; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 14;

[0093] Table 13: Calculation process parameters

[0094]

[0095] Table 14: Actual absorption rate of each element

[0096]

[0097]

[0098] In Table 14, the unit of dosage (amount added) is kg.

[0099] (2) After alloying, the composition of the ladle is C 0.70%, Si 0.61%, Mn 0.90%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 131 tons, the amount of carbon powder alloy added is 1260kg, the C content in the carbon powder is 98.5%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.65%; the amount of ferrosilicon alloy added is 1398kg, the Si content in the ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.61%; the amount of ferromanganese alloy added is 1850kg, the Mn content in the ferromanganese is 69.5%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.82%; the calculation results show that: the absorption rate of C element is 68.61%, the absorption rate of Mn element is 83.55%, and the absorption rate of Si element is 78.09%.

[0100] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

[0101] Embodiment 8:

[0102] (1) In a top and bottom combined blowing converter, the steel grade smelted is U71Mn rail steel, the C content at the converter end point is 0.20%, and carbon powder, silicon manganese and ferromanganese are added during the steel tapping process for alloying. The C loss during the steel tapping process is calculated as 0.042%, the maximum absorption rate of the C element is calculated as 80%, the maximum absorption rate of the Mn element is calculated as 95%, and the maximum absorption rate of the Si element is calculated as 92%. According to formulas (Ⅰ) and (Ⅱ), the absorption rate of the C element in the final alloying process is 78.29%, the absorption rate of the Mn element is 93.96%, and the absorption rate of the Si element is 90.32%. The calculation process parameters and calculated absorption rates using formulas (Ⅰ) and (Ⅱ) are shown in Table 15; the actual parameters and actual absorption rates of each element during the smelting process are shown in Table 16;

[0103] Table 15: Calculation process parameters

[0104]

[0105] Table 16: Actual absorption rate of each element

[0106]

[0107]

[0108] In Table 16, the unit of dosage (amount added) is kg.

[0109] (2) After alloying, the composition of the ladle is C 0.80%, Si 0.40%, Mn 0.98%, the actual absorption rate of each element is calculated according to formula (A) and (B), wherein the amount of molten steel tapping is 135 tons, the amount of carbon powder alloy added is 1050kg, the C content in the carbon powder is 98.5%, and the difference between the C content of the molten steel in the ladle and the C content in the converter after alloying is 0.60%; the amount of ferrosilicon alloy added is 820kg, the Si content in ferrosilicon is 73%, and the difference between the Si content in the molten steel in the ladle and the Si content in the converter after alloying is 0.40%; the amount of ferromanganese alloy added is 1860kg, the Mn content in ferromanganese is 69.8%, and the difference between the Mn content in the molten steel in the ladle and the Mn content in the converter after alloying is 0.90%; the calculation results show that: the absorption rate of C element is 78.32%, the absorption rate of Mn element is 93.58%, and the absorption rate of Si element is 90.21%.

[0110] From the above results, it can be seen that the actual absorption rate of each element in the alloying process is basically consistent with the calculated value of this method. The alloying process has achieved the established goals and laid a good foundation for the next smelting process.

Claims

1. An accurate control method for alloying rail steel converter tapping, characterized in that: In the converter steelmaking process, alloys are added for alloying, and the amount of each alloy added is calculated according to the absorption rate of element E in the alloy calculated by the following formula (I); Among them, C loss – Loss of C element during converter steelmaking, %; C conv – Carbon content of converter steel, %; – Corrected value of carbon content, %; – Balance parameters; – Balance parameters related to carbon and oxygen content in molten steel; – Maximum absorption rate of element E in the alloy, %; Y E –Absorption rate of element E in the alloy, %.

2. The accurate control method for alloying rail steel converter tapping according to claim 1, characterized in that: Said The following (II) is used for calculation; in, – The influence coefficient of bottom blowing and stirring on the absorption rate of element E; – is the general influence coefficient of bottom blowing stirring alloy, which can be taken as 0.7 to 1.0 according to the bottom blowing intensity; –The influence coefficient of decarburization on the absorption rate of element E.

3. The accurate control method for alloying rail steel converter tapping according to claim 2, characterized in that: The element E is C, Si or Mn.

4. The accurate control method for alloying rail steel converter tapping according to claim 3 is characterized by: When the element E is C, The value is 0.

011. The value is -15. The value is 0.

005. The value is -0.5; the maximum absorption rate of element C Calculated at 78% to 80%; When the element E is Mn, The value is 0.

013. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Mn Calculated at 93% to 95%; When the element E is Si, The value is 0.

018. The value is -20. The value is 0. The value is -0.7; the maximum absorption rate of element Si Calculated based on 90% to 92%.

5. The accurate control method for alloying rail steel converter tapping according to any one of claims 1 to 4, characterized in that: The amount of C element loss during the converter steel tapping process C loss The value is determined according to the different C content at the end point: When the C content at the converter end point is ≤0.10%, C loss Take 0.025%; when the C content at the converter end point is between 0.10% and 0.20%, C loss Take 0.035%; when the C content of the converter end point is ≥ 0.20%, C loss Take 0.042%.

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