Method for prolonging furnace life

Abstract

The invention discloses a method for prolonging the service life of a furnace, which comprises the following steps: 1) adding molten iron, waste steel and slag charge into a furnace body, and carrying out steelmaking at the steelmaking temperature of 1630-1650 DEG C; (2) after one casting time of continuous casting is finished, a tundish is replaced for 2-3 hours during continuous casting, and the weak part of the converter lining is maintained; the continuous casting period is shortened by 2-3 minutes, and the temperature of a steel ladle is increased by 5-10 DEG C; (3) the pulling speed of a continuous casting machine is increased, the temperature required by a converter for continuous casting is reduced, and the superheat degree of tundish molten steel is controlled to be within 10-20 DEG C; (4) after steelmaking of the converter body is finished, the carbon content of the converter end point is controlled; and after the converter turns down, sampling and temperature measurement are completed, tapping is directly carried out according to different test end point component results. And (5) measuring the thickness of the furnace lining every week by using a thickness measuring instrument, and mastering the change condition of the furnace lining. Through carbon-preserving tapping, unequal-sample tapping and continuous casting optimization processes, the steel casting temperature is reduced, the tapping temperature of a converter is reduced, and furnace lining corrosion is reduced; the scrap steel ratio is increased, and the consumption of molten iron (ore, coke and the like) is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking, and in particular to a method for increasing furnace life. Background Art

[0002] Steelmaking refers to controlling the carbon content (generally less than 2%), eliminating harmful elements such as P, S, O, and N, retaining or increasing beneficial elements such as Si, Mn, Ni, and Cr, and adjusting the ratio between elements to obtain the best performance. Steelmaking pig iron is placed in a steelmaking furnace and smelted according to a certain process to obtain steel. Steel products include steel ingots, continuous casting billets, and various steel castings directly cast. The steel usually refers to steel rolled into various steel products. Steel belongs to ferrous metals, but steel is not completely equal to ferrous metals.

[0003] In the steelmaking process, a converter is needed. Long-term operation of the converter will cause erosion of the converter lining, affecting its service life, thereby increasing production costs. Therefore, a method to increase the life of the furnace is required. Summary of the invention

[0004] The purpose of the present invention is to provide a method for improving the furnace life by tapping steel with carbon preservation, tapping steel with different samples, optimizing the continuous casting process, lowering the steel pouring temperature, lowering the converter tapping temperature, and reducing the erosion of the furnace lining; increasing the scrap steel ratio and reducing the consumption of molten iron (ore, coke, etc.).

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for increasing furnace life, the method comprising the following steps:

[0007] Step 1) adding molten iron, scrap steel and slag into a converter to perform steelmaking at a temperature of 1630-1650° C.;

[0008] Step 2) After a continuous casting is completed, the tundish is replaced for 2-3 hours, and the weak parts of the converter lining are maintained; the continuous casting cycle is shortened by 2-3 minutes, and the ladle temperature is increased by 5-10°C;

[0009] Step 3) The continuous casting machine increases the casting speed, the continuous casting requires the converter temperature to drop, and the superheat of the molten steel in the tundish is controlled within 10-20°C;

[0010] Step 4) During the converter steelmaking process, the carbon content at the converter endpoint is controlled; after the converter downflow sampling and temperature measurement are completed, steel is directly tapped without waiting for the test endpoint composition results to come out.

[0011] Step 5) Use a thickness gauge to measure the thickness of the furnace lining every week to understand the changes in the furnace lining.

[0012] Furthermore: in the step 1), the mass ratio of molten iron, scrap steel and slag is 75-80:15-18:2-10.

[0013] Furthermore: in the step 2), the time of changing pouring is used to carry out brick patching, deduction patching and casting patching.

[0014] Further: in the step 3), the continuous casting requires the converter temperature to be reduced to 1550°C.

[0015] Furthermore: in the step 3), the oxygen content of the molten steel is increased by 80-100 ppm.

[0016] Furthermore: in the step 4), the carbon content at the end point is greater than 0.08%.

[0017] Further: in the step 4), the temperature measured is 1630-1650°C.

[0018] Further: in the step 4), the components detected by different assays are carbon, manganese, phosphorus and sulfur.

[0019] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0020] (1) By tapping steel with different samples, the furnace soaking time is reduced and the smelting cycle is shortened. Tapping steel with different samples, controlling the tapping temperature, using the time of changing pouring, bricking, patching and throwing the converter, and using a thickness gauge to monitor the converter lining; optimizing the pouring temperature of continuous casting from 1560℃ to 1550℃, shortening the casting cycle, fastening the ladle turnover, and reducing the ladle temperature. Optimizing the continuous casting process, reducing the pouring temperature, reducing the tapping temperature of the converter, and reducing the erosion of the furnace lining; increasing the scrap steel ratio and reducing the consumption of molten iron (ore, coke, etc.). Improving the furnace life to meet production needs.

[0021] (2) The blast furnace did not slow down or stop blowing due to the converter condition; the continuous casting did not stop pouring due to the converter condition; energy conservation and consumption reduction were achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the first erosion diagram of the furnace lining in the prior art.

[0023] Figure 2 This is the second erosion diagram of the furnace lining in the prior art.

[0024] Figure 3 This is the third erosion diagram of the furnace lining in the prior art. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Embodiment 1:

[0027] Molten iron, scrap steel and slag are added to the converter for steelmaking. If the temperature is too high (≥1655℃), the oxygen content of the molten steel will increase accordingly, and if the temperature is too low (≤1625℃), steel cannot be produced.

[0028] After a continuous casting is completed, the tundish needs to be replaced and the weak points of the converter lining need to be maintained. The continuous casting cycle is shortened. After the continuous casting process is optimized, the hot operation time of the empty ladle is short and the heat loss of the ladle is reduced.

[0029] Use the time of recasting to carry out brick patching, buckle patching and throw patching; brick patching: use tools to send converter bricks to the weak parts of the lining for maintenance; buckle patching: put the patching material into the scrap steel bucket, use the crane to pour the patching material into the converter for lining maintenance; throw patching: the furnace worker manually puts the patching material (also called hand throwing material) into the converter for lining maintenance. The above measures are all aimed at prolonging the service life of the converter lining.

[0030] The casting speed of the continuous casting machine is increased, from the original casting cycle of 31 minutes to 28 minutes / furnace. The temperature required for the converter for continuous casting is reduced from 1560℃ to 1550℃, and the superheat of the molten steel in the tundish is strictly controlled. The ladle turnover is fast, which reduces the heat loss of the ladle, and the converter tapping temperature is reduced by about 10℃; due to the low tapping temperature and low oxygen content in the molten steel, the erosion of the furnace lining is small, which increases the service life of the converter lining. After the supplementary blowing, the oxygen content of the molten steel increases, the residual manganese in the molten steel increases by 0.03-0.05%, and the silicon-manganese alloy per ton of steel decreases by 0.43-0.71kg. The oxygen content of the molten steel is low, and the FeO in the slag is ≤12%, so the molten steel has little erosion on the furnace lining.

[0031] The converter smelting process controls the carbon content at the converter endpoint; after sampling and temperature measurement of the converter, steel is tapped directly without waiting for the test results of the endpoint components. The test components mainly test carbon, manganese, phosphorus and sulfur, and the tapping temperature is 1635℃. It takes 2 minutes and 30 seconds for the test results to come out, and tapping directly can save 1 minute and 30 seconds, reducing the time for molten steel to soak the furnace lining, reducing the consumption of the furnace lining, and improving the converter operation rate, which is called tapping without waiting for samples.

[0032] The carbon content at the end of the converter is greater than 0.08%. Due to the high carbon content, the molten steel has high purity, low oxygen content, and high residual manganese content, which saves deoxidizing materials and alloy consumption. The low oxygen content has little erosion on the converter lining, which increases the service life of the converter lining and reduces the consumption of furnace repair materials, that is, carbon-preserving steel production. Compared with the end carbon greater than and less than 0.08%, the end manganese content increases by 0.057%, which is equivalent to reducing 120kg of silicon-manganese alloy per furnace and 0.86kg per ton of steel. A total of 21,150 furnaces were produced during the furnace campaign. According to the qualified steel billet volume of 139t, a total of 29.3985 million tons were produced, and 34.1843 tons of silicon-manganese alloy were saved.

[0033] Use thickness gauges to measure the thickness of the furnace lining every week to understand the changes in the furnace lining and to promptly detect when the furnace condition deteriorates. Through operation and furnace repair maintenance, the service life of the converter lining can be extended to prevent leakage accidents. Use thickness gauges to measure the converter lining regularly, repair weak areas with bricks, and reduce the consumption of repair materials by 0.05kg per ton of steel.

[0034] The other examples were all operated according to the preparation method in Example 1. The present invention is further described in detail below in conjunction with the examples, as shown in Table 1.

[0035] Table 1 Process parameters of the embodiment of the present invention

[0036]

[0037] Through the steelmaking of the embodiment, the whole furnace campaign produced 293.985 million tons of qualified steel billets, saving 147 tons of supplementary materials, 3163*147=464961 yuan. The silicon-manganese alloy per ton of steel was reduced by 0.43-0.71kg, 0.51*2939850*5811 / 1000=7687561 yuan.

[0038] The temperature of each furnace of steel is reduced by 5-10℃, 1℃=0.6 yuan, 21150*0.6*7=88830 yuan.

[0039] Total: 464,961+7,687,561+88,830=82,413,520 yuan.

[0040] Although the present invention is described herein with reference to a number of illustrative embodiments of the present invention, it will be appreciated that those skilled in the art may devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, drawings, and claims, a variety of variations and modifications may be made to the components and / or layout of the subject combination layout. In addition to the variations and modifications made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A method for increasing furnace life, characterized in that: The method comprises the following steps: Step 1) After adding molten iron, scrap steel and slag into the converter, steelmaking is carried out at a temperature of 1630-1650°C; Step 2) After a continuous casting is completed, the tundish is replaced for 2-3 hours, and the weak parts of the converter lining are maintained; the continuous casting cycle is shortened by 2-3 minutes, and the ladle temperature is increased by 5-10°C; Step 3) The continuous casting machine increases the casting speed, the continuous casting requires the converter temperature to drop, and the superheat of the molten steel in the tundish is controlled within 10-20°C; Step 4) Control the carbon content at the converter endpoint during the steelmaking process; after sampling and temperature measurement of the converter are completed, steel is directly tapped without waiting for the test results of the endpoint composition. Step 5) Use a thickness gauge to measure the thickness of the furnace lining every week to understand the changes in the furnace lining.

2. A method for increasing furnace life according to claim 1, characterized in that: In the step 1), the mass ratio of molten iron, scrap steel and slag is 75-80:15-18:2-10.

3. A method for increasing furnace life according to claim 1, characterized in that: In the step 2), the time of changing pouring is used to carry out brick patching, deduction patching and casting patching.

4. A method for increasing furnace life according to claim 1, characterized in that: In the step 3), the continuous casting requires the converter temperature to drop to 1555°C.

5. A method for increasing furnace life according to claim 1, characterized in that: In the step 3), the oxygen content of the molten steel increases by 80-100 ppm.

6. A method for increasing furnace life according to claim 1, characterized in that: In the step 4), the carbon content at the end point is greater than 0.08%.

7. A method for increasing furnace life according to claim 1, characterized in that: In the step 4), the temperature measured is 1630-1650°C.

8. A method for increasing furnace life according to claim 1, characterized in that: In the step 4), the components detected by different assays are carbon, manganese, phosphorus and sulfur.

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