CN114292981A - Method for smelting high-temperature low-manganese steel in later-stage converter campaign - Google Patents
Method for smelting high-temperature low-manganese steel in later-stage converter campaign Download PDFInfo
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- CN114292981A CN114292981A CN202111336965.4A CN202111336965A CN114292981A CN 114292981 A CN114292981 A CN 114292981A CN 202111336965 A CN202111336965 A CN 202111336965A CN 114292981 A CN114292981 A CN 114292981A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000003723 Smelting Methods 0.000 title claims abstract description 28
- 229910000617 Mangalloy Inorganic materials 0.000 title claims abstract description 19
- 239000011572 manganese Substances 0.000 claims abstract description 54
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 51
- 239000010959 steel Substances 0.000 claims abstract description 51
- 238000007664 blowing Methods 0.000 claims abstract description 47
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 41
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 41
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000002893 slag Substances 0.000 claims abstract description 30
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000001301 oxygen Substances 0.000 claims abstract description 22
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 22
- 238000010079 rubber tapping Methods 0.000 claims abstract description 21
- 229910052742 iron Inorganic materials 0.000 claims abstract description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 14
- 238000005070 sampling Methods 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 2
- 238000005187 foaming Methods 0.000 claims description 2
- 238000009749 continuous casting Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 5
- 235000011941 Tilia x europaea Nutrition 0.000 description 5
- 239000010459 dolomite Substances 0.000 description 5
- 229910000514 dolomite Inorganic materials 0.000 description 5
- 239000004571 lime Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 235000019738 Limestone Nutrition 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000006028 limestone Substances 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 238000009489 vacuum treatment Methods 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 2
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- CYUOWZRAOZFACA-UHFFFAOYSA-N aluminum iron Chemical compound [Al].[Fe] CYUOWZRAOZFACA-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention discloses a method for smelting high-temperature low-manganese steel in the later stage of converter campaign, which comprises the following steps: firstly, filling molten iron and scrap steel into a converter, shaking the converter to a converting position, filling slag charge, and starting main converting; step two, measuring the temperature of a molten pool and sampling when the main converting is finished, wherein the target temperature is 1580-1620 ℃; target carbon content [ C ]: 0.10% -0.20%; the content of target manganese [ Mn ] is less than or equal to 0.20 percent; thirdly, the oxygen lance is lowered to start secondary blowing, and when the secondary blowing is finished, the converter is shaken to be inverted to 80-95 degrees towards the feeding side; and fourthly, swinging the converter to a blowing position, feeding an oxygen lance for additional blowing, blowing the temperature and components of molten steel in the converter to a target range of a terminal point, measuring the temperature, oxygen content and carbon content of a molten pool, and tapping steel when the requirements are met. The method effectively solves the problem of 'manganese return' phenomenon when smelting high-temperature low-manganese steel in the later period of converter service by turning down the converter to homogenize the components and temperature of the molten pool in the later period of converter service, and the process is simple to operate and good in popularization.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a method for smelting high-temperature low-manganese steel in the later stage of converter service, which can effectively solve the problem of 'manganese return' in the later stage of converter service for smelting high-temperature low-manganese steel.
Background
With the development of steel-making technology, converter steel-making has become one of the main means of steel-making production in the world today. At present, most steel mills use top-bottom combined blown converters, but in the actual production process, the blast furnace age is generally pursued, and under the effects of long-term slag splashing process, furnace type maintenance measures such as furnace bottom height control and the like, the converter generally does not have the bottom blowing function at the later stage of the campaign of the top-bottom combined blown converter, when the converter blows low-manganese steel, the manganese content is often very low (the manganese can reach below 0.08% by sampling at the blowing end point) when the converter blows low-manganese steel to the end point due to the fact that the carbon content in molten steel is greatly reduced, the stirring of a molten pool in the converter is insufficient, the dead zone of the molten pool is more, and the oxidation process of the manganese at the later stage is severely restricted, but because the molten steel has uneven molten steel water composition and temperature in the molten steel pool of the converter, the manganese content of the molten steel rapidly rises (commonly called as 'manganese recovery'), so as to cause smelting failure; in addition, when a converter-RH smelting process (such as HiB steel) is adopted, after deoxidation alloying of converter tapping, in order to meet the temperature drop of the RH vacuum treatment process, the temperature of converter tapping needs to be high enough, which is contradictory to the demanganization of the converter, because when the temperature is too high during converter smelting, carbon-oxygen reaction is violent, decarburization speed is accelerated, after (FeO) in slag is rapidly reduced, (MnO) can participate in oxidation reaction of carbon, so that MnO is reduced, manganese enters molten steel again, so that the end point manganese is high, and demanganization of the converter fails.
Disclosure of Invention
Based on the technical problems, the invention aims to provide a method for smelting high-temperature low-manganese steel in the later stage of converter service, which effectively solves the problem of 'manganese return' in the later stage of converter service during smelting of high-temperature low-manganese steel by pouring the components and temperature of a molten pool uniformly.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for smelting high-temperature low-manganese steel in the later stage of converter campaign comprises the following steps:
firstly, filling molten iron and scrap steel into a converter, shaking the converter to a converting position, filling slag charge, and starting main converting;
step two, measuring the temperature of a molten pool and sampling when the main converting is finished, wherein the target temperature is 1580-1620 ℃; target carbon content [ C ]: 0.10% -0.20%; the content of target manganese [ Mn ] is less than or equal to 0.20 percent;
thirdly, the oxygen lance is lowered to start secondary blowing, and when the secondary blowing is finished, the converter is shaken to be inverted to 80-95 degrees towards the feeding side;
and fourthly, swinging the converter to a blowing position, feeding an oxygen lance for additional blowing, blowing the temperature and components of molten steel in the converter to a target range of a terminal point, measuring the temperature, oxygen content and carbon content of a molten pool, and tapping steel when the requirements are met.
Further, in the third step of furnace dumping, the redundant furnace slag in the furnace is dumped into the slag pot, the quantity of the furnace slag is properly reduced, the quantity of manganese contacting with molten steel is further reduced, the furnace rocking operation needs to be slow, the furnace slag is prevented from splashing, and the foaming degree of the furnace slag in the furnace is observed.
Furthermore, in the first main converting process, the adding amount of converter slag charge and coolant is adjusted according to the temperature of molten iron, the components of the molten iron and the proportion of the molten iron and scrap steel, the temperature rise speed of a molten pool is properly controlled in the process, the target temperature is ensured to be 1580-1620 ℃ when the main converting process is finished, and the phenomenon that the slag is dried back due to the rapid rise of the temperature of the molten pool, so that a large amount of MnO is reduced by carbon to increase the manganese content of the molten steel is avoided.
Further, the purpose of the third step of secondary blowing is to increase the oxygen content in the molten steel, oxidize excess manganese in the molten steel, and increase the converter bath temperature.
Furthermore, after the third step of secondary blowing is finished, the process of pouring out slag in a converter mainly has two aims, namely, the redundant slag is poured out, and the quantity of manganese in the slag contacting with molten steel is reduced; certainly, the heat can be dissipated to a certain extent in the process of deslagging by shaking the furnace, and the temperature is generally 20-50 ℃; secondly, the furnace is shaken to play a role of activating a molten pool, so that the dead zone range of a slow or stagnation state of partial molten steel chemical reaction in the molten pool of the converter is reduced, and manganese can be promoted to be further removed by oxidation.
And further, the supplementary blowing in the fourth step aims at further blowing oxygen, improving the oxygen content in molten steel in the converter, promoting further oxidation of redundant manganese in a molten pool, and simultaneously carrying out carbon pulling and temperature pulling until the target requirement of end point tapping is met.
Further, the end temperature of the converter in the fourth step is 1670-1720 ℃, and after tapping is carried out by the converter, the manganese content in the molten steel is below 0.10%.
Compared with the prior art, the invention has the beneficial effects that:
the method for smelting the high-temperature low-manganese steel in the later stage of the converter service effectively solves the problem of 'manganese return' in the later stage of the converter service when smelting the high-temperature low-manganese steel by pouring the components and the temperature of the molten pool uniformly, and has the advantages of simple operation and good popularization.
Detailed Description
The technical solutions and effects of the present invention will be further described with reference to specific examples, but the scope of the present invention is not limited thereto.
The molten steel components of the invention are all in weight percentage.
Example 1
In the present example, the manganese content [ Mn ] of the finished product was smelted by a 150t converter which had no bottom blowing condition: the process of 0.09-0.11% of oriented silicon steel HiB illustrates the method for smelting high-temperature low-manganese steel in the later stage of the converter campaign.
HiB steel belongs to low-manganese silicon steel, and generally adopts a converter-RH smelting process, so that the steel tapping of the converter requires low manganese content, and the molten steel is ensured not to return to manganese. When the steel grade is produced in an Angang steel secondary smelting mill, the tundish target temperature is required to be 1510-1530 ℃ during continuous casting and continuous casting. The temperature drop mainly comprises that the temperature drops about 70 ℃ in the process from converter tapping to RH, about 60 ℃ in RH vacuum treatment, and about 45 ℃ in RH vacuum breaking to continuous casting, the end point temperature of the converter can be inferred to be 1695 ℃, namely, the temperature of converter tapping needs to be guaranteed, and low manganese conditions are required.
In the process of smelting in the second furnace of the embodiment, the age of the converter is 7412, and the height of the bottom of the converter needs to be maintained because the shape of the converter is ensured, so that the converter does not have the bottom blowing function.
The smelting process comprises the following steps:
charging steel materials, molten iron: 158.02t, scrap steel 25.51t, molten iron temperature 1353 ℃ before entering the converter, and the content of silicon in the molten iron [ Si ]: 0.39 percent; manganese content [ Mn ]: 0.29 percent; p content [ P ]: 0.091 percent.
After the converter main blowing starts, the total amount of initial slag materials added in small batches is 5521kg of lime and 3185kg of dolomite while blowing by an oxygen lance, and the total amount of the initial slag materials added in three small batches within 4min of blowing is 1948kg, 1877kg and 1696kg respectively; the dolomite is added in three small batches of 1222kg, 1197kg and 766kg respectively.
After the initial slag is blown and formed, two batches of slag materials are added, and the slag amount, the alkalinity and the temperature of a molten pool are continuously increased; 2685kg of lime is added into the two batches of slag materials, and 200 and 400kg of lime are added into each small batch; the total amount of the dolomite is 1301kg, and the addition amount of each small batch is 150-400 kg; a total of 3958kg of limestone was added, and 200-400kg of limestone was added in small batches. Two batches of lime, dolomite and limestone are alternately added, and the temperature of the molten pool is controlled while slagging is carried out.
When converter blowing is started for 12 minutes and 11 seconds, main blowing is finished, and total oxygen blowing amount is 7927m3Measuring the temperature of molten steel in a molten pool by a lower sublance and sampling, wherein the temperature of the molten steel in the molten pool is 1617 ℃, the fixed carbon of the sublance is 0.185%, simultaneously taking the sample I and starting sublevel blowing, and the blowing oxygen amount of the sublevel blowing is 492m3(ii) a After the auxiliary blowing is finished, the oxygen lance is raised, the furnace is slowly shaken to 92 degrees towards the feeding side, the furnace is observed in the furnace shaking process, the furnace slag has certain jumping, when the furnace is shaken to 92 degrees, a small amount of furnace slag (about 2t) overflows from a furnace mouth into a slag pot, the furnace is stayed for 20 seconds to shake the converter to a blowing position, the oxygen lance is lowered again to supplement blowing, the blowing oxygen amount is 948m3Lower sublance temp. measuring 1694 deg.C, oxygen determining [ O ]]: 0.1285 percent, and taking a sample of No. two, shaking the converter to a tapping position, and tapping. During tapping, the components of sample No. 1 and sample No. 2 are respectively transmitted to a converter operating system, and the components are shown in Table 1.
TABLE 1 converter blowing Process sample composition
Adding aluminum iron and ferrosilicon for deoxidation alloying in the tapping process, stirring for 4min in an argon station by soft blowing after tapping, and sampling and detecting that the manganese content is [ Mn ]: 0.089%.
Carrying out RH vacuum treatment, adjusting components and temperature, carrying out continuous casting for pouring, taking a finished product sample in a continuous casting tundish, and detecting the manganese content [ Mn ] of the finished product sample: 0.092 percent.
The smelting of the steel in the converter is finished, from the smelting process, the aim of smelting high-temperature low-manganese steel in the later period of the converter service can be achieved by main converting and auxiliary converting of the converter, deslagging by reversing the converter, homogenizing the components and the temperature, and supplementing converting again, and the manganese return amount of molten steel is less than or equal to 0.02 percent after the converter taps steel.
Comparative example 1
The converter and the smelting steel grade adopted in the comparative example are the same as those in example 1.
The campaign of the converter used in the smelting of this comparative example was 7215, and the converter had no bottom blowing function as in example 1.
Charging steel materials, molten iron: 161.15t, 23.95t of scrap steel, 1344 ℃ of molten iron temperature before entering the converter, and the content of silicon in the molten iron [ Si ]: 0.43 percent; manganese content [ Mn ]: 0.30 percent; p content [ P ]: 0.088 percent.
The modes of main blowing and auxiliary blowing of the converter are the same as the embodiment 1, the total amount of lime added in the main blowing is 8157kg, and the amount of dolomite is 4003 kg; 3857kg of limestone; oxygen blowing amount of 7878m3(ii) a Main blowing end temperature 1619 deg.c, carbon content in molten steel]: 0.158%, manganese content [ Mn ]]: 0.15 percent; oxygen amount blown in secondary converting 1288m3Measuring the temperature of molten steel 1691 deg.C after the secondary blowing, oxygen content [ O ] in the molten steel]: 0.1397%, carbon content in molten steel [ C ]]: 0.030%, manganese content [ Mn ]]: 0.078%; after the secondary blowing, the tapping is carried out by shaking the furnace, the same as the embodiment 1, the ferro-aluminum and the ferro-silicon are added for deoxidation and alloying in the tapping process, the tapping is carried out by soft blowing and stirring for 4min, and the sampling is carried out, the manganese content [ Mn ] in the molten steel]: 0.117 percent, and the manganese content [ Mn ] of the finished product sample is obtained after RH vacuum treatment to continuous casting pouring]：0.12％。
In comparative example 1, the "manganese return" phenomenon appeared during tapping of molten steel, the "manganese return" amount was 0.039%, the fluctuation of manganese content after tapping was large, and it was difficult to ensure the manganese content [ Mn ] of the finished product: 0.09% -0.11% of the total weight of the composition.
Finally, it should be noted that the above-mentioned description is only for illustrating the technical solution of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solution of the present invention by those skilled in the art should be covered in the scope of the claims of the present invention as long as they do not depart from the spirit of the technical solution of the present invention.
Claims (4)
1. A method for smelting high-temperature low-manganese steel in the later stage of converter campaign is characterized by comprising the following steps:
firstly, filling molten iron and scrap steel into a converter, shaking the converter to a converting position, filling slag charge, and starting main converting;
step two, measuring the temperature of a molten pool and sampling when the main converting is finished, wherein the target temperature is 1580-1620 ℃; target carbon content [ C ]: 0.10% -0.20%; the content of target manganese [ Mn ] is less than or equal to 0.20 percent;
thirdly, the oxygen lance is lowered to start secondary blowing, and when the secondary blowing is finished, the converter is shaken to be inverted to 80-95 degrees towards the feeding side;
and fourthly, swinging the converter to a blowing position, feeding an oxygen lance for additional blowing, blowing the temperature and components of molten steel in the converter to a target range of a terminal point, measuring the temperature, oxygen content and carbon content of a molten pool, and tapping steel when the requirements are met.
2. The method for smelting the high-temperature low-manganese steel at the later campaign stage of the converter according to claim 1, wherein the excess slag in the converter is poured into the slag pot in the third step of pouring, so that the amount of the slag is properly reduced, the amount of manganese contacting with the molten steel is further reduced, the operation of shaking the converter is slow, the slag is prevented from splashing, and the degree of foaming of the slag in the converter is observed.
3. The method for smelting high-temperature low-manganese steel according to claim 1, wherein in the first main converting process, the adding amount of converter slag and coolant is adjusted according to the temperature of molten iron, the composition of molten iron, and the ratio of molten iron to scrap, and the temperature rise speed of the molten pool is properly controlled to ensure that the target temperature is 1580 ℃ -1620 ℃ at the end of main converting, so that the phenomenon that a large amount of MnO is reduced by carbon to increase manganese content in molten steel due to rapid rise of the temperature of the molten pool is avoided.
4. The method for smelting the high-temperature low-manganese steel at the later campaign stage of the converter according to claim 1, wherein the end temperature of the converter in the fourth step is 1670 ℃ to 1720 ℃, and the manganese content in the molten steel is below 0.10% after tapping of the converter.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111336965.4A CN114292981A (en) | 2021-11-12 | 2021-11-12 | Method for smelting high-temperature low-manganese steel in later-stage converter campaign |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111336965.4A CN114292981A (en) | 2021-11-12 | 2021-11-12 | Method for smelting high-temperature low-manganese steel in later-stage converter campaign |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1161221A (en) * | 1997-08-22 | 1999-03-05 | Kawasaki Steel Corp | Method for melting low manganese steel |
| CN201660653U (en) * | 2010-02-25 | 2010-12-01 | 鞍钢股份有限公司 | Double-degree-of-freedom converter |
| CN110453032A (en) * | 2019-08-29 | 2019-11-15 | 包头钢铁（集团）有限责任公司 | A method of utilizing the high ultralow manganese steel of manganese molten iron smelting |
| CN113005255A (en) * | 2021-02-23 | 2021-06-22 | 浙江友谊新材料有限公司 | Top-blown smelting device capable of increasing stirring degree |
-
2021
- 2021-11-12 CN CN202111336965.4A patent/CN114292981A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1161221A (en) * | 1997-08-22 | 1999-03-05 | Kawasaki Steel Corp | Method for melting low manganese steel |
| CN201660653U (en) * | 2010-02-25 | 2010-12-01 | 鞍钢股份有限公司 | Double-degree-of-freedom converter |
| CN110453032A (en) * | 2019-08-29 | 2019-11-15 | 包头钢铁（集团）有限责任公司 | A method of utilizing the high ultralow manganese steel of manganese molten iron smelting |
| CN113005255A (en) * | 2021-02-23 | 2021-06-22 | 浙江友谊新材料有限公司 | Top-blown smelting device capable of increasing stirring degree |
Non-Patent Citations (2)
| Title |
|---|
| 于银俊: "安钢150t转炉低锰钢生产实践", 《冶金经济与管理》 * |
| 孙亮: "低锰钢炼钢控锰实践", 《中国冶金》 * |
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Application publication date: 20220408 |