A method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle

Abstract

The invention discloses a method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle, and belongs to the technical field of steel metallurgy and steelmaking. In the smelting process of a 50-350 ton converter, the wear angle of the oxygen lance is detected every 15-25 furnaces, and a functional relationship between the wear angle, the lance position and the jet velocity is established based on the wear angle of the oxygen lance nozzle. According to different wear angles, the oxygen supply system in different blowing periods is accurately adjusted according to the jet velocity change relationship, ensuring that the jet velocity is the same as the design flow rate when impacting the molten pool, and ensuring that the worn oxygen lance nozzle has the same molten pool stirring effect as the newly designed oxygen lance nozzle.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy and steelmaking, and in particular relates to a method for accurately adjusting an oxygen supply system based on the wear angle of an oxygen lance nozzle. Background Art

[0002] The oxygen lance is a key equipment for converter steelmaking. High-pressure and low-speed oxygen is accelerated through the Raoult oxygen lance nozzle to form a supersonic jet with a Mach number of about 2.0, which impacts the converter molten pool to promote the flow of molten steel, improve the mass transfer and heat transfer efficiency, and complete the steelmaking dephosphorization, decarburization and heating tasks. During the converter blowing process, the oxygen lance is damaged mainly at the bottom end face of the nozzle and the side wall within a range of about 2m from the oxygen lance nozzle. The damage to the bottom end face of the oxygen lance nozzle is mainly caused by the thermal scouring caused by the high-temperature slag and the metal droplets dispersed in the slag. After the oxygen lance nozzle outlet is worn, the jet characteristics and the molten pool stirring effect also change. Therefore, with the increase of lance age, the oxygen lance position and oxygen supply intensity should be appropriately adjusted during the converter smelting process to reduce the impact of oxygen lance nozzle wear on converter blowing. Summary of the invention

[0003] In order to solve the problem of deterioration of jet characteristics and molten pool stirring effect after oxygen lance nozzle wear, the purpose of the present invention is to provide a method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle, so as to ensure that the worn oxygen lance nozzle has the same molten pool stirring effect as the newly designed oxygen lance nozzle.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle includes the following process:

[0006] During the oxygen lance blowing process of the converter, according to the different wear angles of the oxygen lance nozzle, the lance position and oxygen supply intensity of the oxygen lance are adjusted according to the following relationship so that the jet velocity when impacting the molten pool is the same as the designed flow velocity;

[0007] v=315.2+4.8α+120.6H-0.2α 2 -75.3H 2 -2.8αH

[0008] Where: v is the jet velocity, m / s; α is the wear angle of the oxygen lance nozzle; H is the gun position of the oxygen lance, m.

[0009] Preferably, the wear angle of the oxygen lance nozzle is divided into four ranges of 0°<α≤8°, 8°<α≤15°, 15°<α≤22°, and 22°<α. In each wear angle range, the oxygen lance position and oxygen supply intensity are adjusted in each stage of the early blowing, middle blowing, and late blowing.

[0010] Preferably, when the oxygen lance nozzle wear angle is 0°<α≤8°, the oxygen lance position and oxygen supply intensity are adjusted as follows:

[0011] Early blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 0-50mm, and the oxygen supply intensity is 2.5-3.5m 3 / (min·t);

[0012] Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 50-100mm, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t);

[0013] Later stage of blowing: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 100-150mm, and the oxygen supply intensity is 3.2-4.2m 3 / (min·t).

[0014] Preferably, when the oxygen lance nozzle wear angle is 8°<α≤15°, the oxygen lance position and oxygen supply intensity are adjusted as follows:

[0015] Early blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 20-70mm, and the oxygen supply intensity is 2.8-3.8m 3 / (min·t);

[0016] Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 70-130mm, and the oxygen supply intensity is 3.3-4.2m 3 / (min·t);

[0017] In the later stage of blowing: based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 130-190mm, and the oxygen supply intensity is 3.6-4.5m 3 / (min·t).

[0018] Preferably, when the oxygen lance nozzle wear angle is 15°<α≤22°, the oxygen lance position and oxygen supply intensity are adjusted as follows:

[0019] Early blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 40-80mm, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t);

[0020] Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 80-140mm, and the oxygen supply intensity is 3.5-4.4m 3 / (min·t);

[0021] Later stage of blowing: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 150-210mm, and the oxygen supply intensity is 3.7-4.7m 3 / (min·t).

[0022] Preferably, when the oxygen lance nozzle wear angle α is greater than 22°, the oxygen lance is replaced.

[0023] Preferably, during the blowing process of the converter using an oxygen lance, the wear angle of the oxygen lance is detected every 15-25 furnaces.

[0024] Preferably, the converter is a 50-350 ton smelting converter, the oxygen lance nozzle used has 4-6 holes, and the Mach number is 1.8-2.2.

[0025] The present invention has the following beneficial effects:

[0026] The method for adjusting the position of the oxygen lance and oxygen supply after the oxygen lance nozzle is worn is suitable for 50-350 ton converters. According to different wear angles of the oxygen lance nozzle, the lance position and oxygen supply intensity are accurately adjusted to reduce the influence of the wear of the oxygen lance nozzle on the converter blowing. After the present invention is adopted, the P content of the molten steel at the end of blowing, the average carbon-oxygen product and the TFe content in the slag can be reduced by 5%-11%, 6%-15% and 3%-9% respectively, effectively reducing the influence of the wear of the oxygen lance nozzle on the converter blowing effect. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the embodiments.

[0028] The technical solution of the present invention is as follows: During the blowing process of the converter using an oxygen lance, the oxygen lance wear angle is detected once every 15-25 furnaces (the specific frequency is selected according to actual conditions, and the present invention does not make specific limitations), and a functional relationship between the wear angle, the lance position and the jet velocity is established based on the oxygen lance nozzle wear angle as follows:

[0029] v=315.2+4.8α+120.6H-0.2α 2 -75.3H 2 -2.8αH

[0030] Where: v is the jet velocity, m / s; α is the wear angle; H is the gun position, m;

[0031] Based on the degree of wear of the oxygen lance nozzle, the wear angle is divided into four ranges: 0°<α≤8°, 8°<α≤15°, 15°<α≤22°, and 22°<α. The oxygen supply system is accurately adjusted according to the wear angle to ensure that the jet velocity is the same as the design velocity when impacting the molten pool, and to ensure that the worn oxygen lance nozzle has the same molten pool stirring effect as the newly designed oxygen lance nozzle. The oxygen supply system is accurately adjusted according to the jet velocity change relationship according to different wear angles;

[0032] When the oxygen lance wear angle is 0°<α≤8°, the oxygen supply system is as follows:

[0033] (1) Early stage of blowing: On the basis of the newly designed oxygen lance (i.e. brand new oxygen lance) at the same time, the lance position is lowered by 0-50mm, and the oxygen supply intensity is 2.5-3.5m 3 / (min·t);

[0034] (2) Mid-blowing period: The oxygen lance position is lowered by 50-100mm based on the newly designed oxygen lance position at the same time, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t);

[0035] (3) Late blowing: Based on the new design oxygen lance position, the lance position is lowered by 100-150mm, and the oxygen supply intensity is 3.2-4.2m 3 / (min·t);

[0036] When the oxygen lance wear angle is 8°<α≤15°, the oxygen supply system is as follows:

[0037] (1) Early stage of blowing: Based on the new design oxygen lance position at the same time, the lance position is lowered by 20-70mm, and the oxygen supply intensity is 2.8-3.8m 3 / (min·t);

[0038] (2) Mid-blowing period: The oxygen lance position is lowered by 70-130mm based on the newly designed oxygen lance position at the same time, and the oxygen supply intensity is 3.3-4.2m 3 / (min·t);

[0039] (3) Late blowing: The oxygen lance position is lowered by 130-190mm based on the newly designed oxygen lance position at the same time, and the oxygen supply intensity is 3.6-4.5m 3 / (min·t);

[0040] When the oxygen lance wear angle is 15°<α≤22°, the oxygen supply system is as follows:

[0041] (1) Early stage of blowing: based on the new design oxygen lance position at the same time, the lance position is lowered by 40-80mm, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t);

[0042] (2) Mid-blowing period: The oxygen lance position is lowered by 80-140mm based on the newly designed oxygen lance position at the same time, and the oxygen supply intensity is 3.5-4.4m 3 / (min·t);

[0043] (3) Late blowing: The oxygen lance position is lowered by 150-210mm based on the newly designed oxygen lance position at the same time, and the oxygen supply intensity is 3.7-4.7m 3 / (min·t);

[0044] When the wear angle is greater than 22°, the oxygen gun nozzle needs to be replaced.

[0045] The method of the invention is applicable to the smelting process of a 50-350 ton converter, and the oxygen lance nozzle used has 4-6 holes and a Mach number of 1.8-2.2.

[0046] Embodiment 1:

[0047] 50-ton converter steelmaking process

[0048] The initial composition of molten iron in the 50-ton converter smelting process is shown in Table 1. It was found that when the oxygen lance wear angle was 4°, if the present invention was not used, the P content, carbon-oxygen accumulation and TFe content in the slag at the end of converter blowing were 0.032%, 0.027% and 14.58% respectively.

[0049] Table 1

[0050]

[0051] The invention is used when the oxygen lance wear angle is 4°: the oxidation of Si, Ti and Mn is the main process in the early stage of blowing, and the oxidation of C is slow. At this time, the lance position of the newly designed oxygen lance is reduced by 10mm based on the lance position of the same period, and the oxygen supply intensity is 2.6m 3 / (min·t); In the middle of blowing, the oxidation of Si, Ti and Mn has been basically completed. At this time, slag overflow and metal splashing should be prevented to promote the continued dissolution of lime and delay the transformation of CO reaction mechanism. The lance position of the newly designed oxygen lance is reduced by 55mm on the basis of the same period lance position, and the oxygen supply intensity is 3.1m 3 / (min·t); in the later stage of blowing, promote the emulsification of steel and slag, make the reaction of steel slag close to equilibrium, so as to improve the distribution ratio of phosphorus and sulfur, reduce the oxygen content of molten steel at the end and the TFe content in slag. The lance position is reduced by 110mm based on the lance position of the new design at the same time, and the oxygen supply intensity is 3.3m 3 / (min·t). At this time, the P content, carbon-oxygen product and TFe content in the slag at the end of converter blowing are 0.029%, 0.025% and 14.13% respectively. Compared with the case where the invention is not adopted, the P content, carbon-oxygen product and TFe content in the slag at the end of converter blowing are reduced by 9.4%, 7.4% and 3.1% respectively, which effectively reduces the influence of oxygen lance nozzle wear on converter blowing effect.

[0052] Embodiment 2:

[0053] 120 ton converter steelmaking process

[0054] The initial composition of molten iron in the 120-ton converter smelting process is shown in Table 2. It was found that when the oxygen lance wear angle was 10°, if the present invention was not used, the P content, carbon-oxygen accumulation and TFe content in the slag at the end of converter blowing were 0.033%, 0.029 and 14.6% respectively.

[0055] Table 2

[0056]

[0057] The invention is used when the oxygen lance wear angle is 10°: the oxidation of Si, Ti and Mn is the main process in the early stage of blowing, and the oxidation of C is slow. The lance position is reduced by 30mm based on the lance position of the new design at the same time, and the oxygen supply intensity is 2.9m 3 / (min·t); In the middle of blowing, the oxidation of Si, Ti and Mn has been basically completed. At this time, slag overflow and metal splashing should be prevented to promote the continued dissolution of lime and delay the transformation of CO reaction mechanism. The lance position of the newly designed oxygen lance is reduced by 80mm on the basis of the same period lance position, and the oxygen supply intensity is 3.4m 3 / (min·t); in the later stage of blowing, promote the emulsification of steel and slag, make the reaction of steel slag close to equilibrium, so as to improve the distribution ratio of phosphorus and sulfur, reduce the oxygen content of terminal molten steel and TFe content in slag. The lance position is reduced by 140mm based on the lance position of the new design at the same time, and the oxygen supply intensity is 3.7m 3 / (min·t). At this time, the P content, carbon-oxygen product and TFe content in the slag at the end of converter blowing are 0.029%, 0.026% and 14.1% respectively. Compared with the case where the invention is not adopted, the P content, carbon-oxygen product and TFe content in the slag at the end of converter blowing are reduced by 12.1%, 10.3% and 3.4% respectively, effectively reducing the influence of oxygen lance nozzle wear on converter blowing effect.

[0058] Embodiment 3:

[0059] 300-ton converter steelmaking process

[0060] The initial composition of molten iron in the 300-ton converter smelting process is shown in Table 3. It was found that when the oxygen lance wear angle was 20°, if the present invention was not used, the P content, carbon-oxygen accumulation and TFe content in the slag at the end of converter blowing were 0.029%, 0.028% and 14.37% respectively.

[0061] Table 3

[0062]

[0063] The invention is used when the oxygen lance wear angle is 20°: the oxidation of Si, Ti and Mn is the main process in the early stage of blowing, and the oxidation of C is slow. At this time, the lance position of the newly designed oxygen lance is reduced by 70mm based on the lance position of the same period, and the oxygen supply intensity is 3.5m 3 / (min·t); In the middle of blowing, the oxidation of Si, Ti and Mn has been basically completed. At this time, slag overflow and metal splashing should be prevented to promote the continued dissolution of lime and delay the transformation of CO reaction mechanism. The lance position of the newly designed oxygen lance is reduced by 120mm on the basis of the same period lance position, and the oxygen supply intensity is 4.1m 3 / (min·t); in the later stage of blowing, promote the emulsification of steel and slag, make the reaction of steel slag close to equilibrium, so as to improve the distribution ratio of phosphorus and sulfur, reduce the oxygen content of molten steel at the end and the TFe content in slag. The lance position is reduced by 190mm based on the lance position of the new design at the same time, and the oxygen supply intensity is 4.3m 3 / (min·t). At this time, the P content, carbon-oxygen product and TFe content in the slag of the final converter blowing were 0.027%, 0.024% and 13.3% respectively. Compared with the case where the invention was not adopted, the P content, carbon-oxygen product and TFe content in the final converter blowing were reduced by 6.9%, 14.3% and 7.4% respectively, effectively reducing the influence of oxygen lance nozzle wear on the converter blowing effect.

Claims

1. A method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle, characterized in that: The process includes the following: During the oxygen lance blowing process of the converter, according to the different wear angles of the oxygen lance nozzle, the lance position and oxygen supply intensity of the oxygen lance are adjusted according to the following relationship so that the jet velocity when impacting the molten pool is the same as the designed flow velocity; Where: is the jet velocity, m / s; is the wear angle of the oxygen lance nozzle; is the position of the oxygen lance, m; The wear angle of the oxygen lance nozzle is divided into 0°< ≤8°、8°< ≤15°、15°< ≤22°、22°< Four ranges, under each wear angle range, the oxygen lance position and oxygen supply intensity are adjusted in each stage of the early blowing, middle blowing and late blowing; When the oxygen lance nozzle wear angle is 0°< When the temperature is ≤8°, the oxygen gun position and oxygen supply intensity are adjusted as follows: Early blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 0-50mm, and the oxygen supply intensity is 2.5-3.5m 3 / (min·t); Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 50-100mm, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t); Later stage of blowing: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 100-150mm, and the oxygen supply intensity is 3.2-4.2m 3 / (min·t); When the oxygen lance nozzle wear angle is 8°< When the temperature is ≤15°, the oxygen gun position and oxygen supply intensity are adjusted as follows: Early stage of blowing: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 20-70mm, and the oxygen supply intensity is 2.8-3.8m 3 / (min·t); Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 70-130mm, and the oxygen supply intensity is 3.3-4.2m 3 / (min·t); In the later stage of blowing: based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 130-190mm, and the oxygen supply intensity is 3.6-4.5m 3 / (min·t); When the oxygen lance nozzle wear angle is 15°< When the temperature is ≤22°, the oxygen gun position and oxygen supply intensity are adjusted as follows: Early blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 40-80mm, and the oxygen supply intensity is 3.0-4.0m 3 / (min·t); Mid-blowing period: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 80-140mm, and the oxygen supply intensity is 3.5-4.4m 3 / (min·t); Later stage of blowing: Based on the new oxygen lance position at the same time, the oxygen lance position is lowered by 150-210mm, and the oxygen supply intensity is 3.7-4.7m 3 / (min·t).

2. A method for accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle according to claim 1, characterized in that: When the oxygen lance nozzle wear angle When it is greater than 22°, replace the oxygen gun.

3. The method of accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle according to claim 1 is characterized in that: During the oxygen lance blowing process in the converter, the wear angle of the oxygen lance is checked every 15-25 furnaces.

4. The method of accurately adjusting the oxygen supply system based on the wear angle of the oxygen lance nozzle according to claim 1 is characterized in that: The converter is a 50-350 ton smelting converter, the oxygen lance nozzle used has 4-6 holes and the Mach number is 1.8-2.2.

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