CN117625887A - Production method for improving inclusion of vacuum refined aluminum-containing steel - Google Patents
Production method for improving inclusion of vacuum refined aluminum-containing steel Download PDFInfo
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- CN117625887A CN117625887A CN202311318634.7A CN202311318634A CN117625887A CN 117625887 A CN117625887 A CN 117625887A CN 202311318634 A CN202311318634 A CN 202311318634A CN 117625887 A CN117625887 A CN 117625887A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 85
- 239000010959 steel Substances 0.000 title claims abstract description 85
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 39
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 238000004519 manufacturing process Methods 0.000 title description 6
- 238000007670 refining Methods 0.000 claims abstract description 60
- 239000002893 slag Substances 0.000 claims abstract description 60
- 238000000034 method Methods 0.000 claims abstract description 53
- 238000005266 casting Methods 0.000 claims abstract description 16
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 15
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 15
- 238000009749 continuous casting Methods 0.000 claims abstract description 15
- 239000004571 lime Substances 0.000 claims abstract description 15
- 238000003723 Smelting Methods 0.000 claims abstract description 13
- 239000011575 calcium Substances 0.000 claims abstract description 12
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 10
- 239000005997 Calcium carbide Substances 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims abstract description 8
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 claims abstract description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910001570 bauxite Inorganic materials 0.000 claims abstract description 7
- 239000007787 solid Substances 0.000 claims abstract description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims abstract description 6
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 6
- 239000006004 Quartz sand Substances 0.000 claims abstract description 3
- 238000007664 blowing Methods 0.000 claims description 20
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 12
- 239000000956 alloy Substances 0.000 claims description 8
- 229910045601 alloy Inorganic materials 0.000 claims description 8
- 238000010079 rubber tapping Methods 0.000 claims description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 238000009489 vacuum treatment Methods 0.000 claims description 7
- 229910052786 argon Inorganic materials 0.000 claims description 6
- 238000007872 degassing Methods 0.000 claims description 6
- 238000003825 pressing Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 3
- 238000005275 alloying Methods 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- 239000002436 steel type Substances 0.000 abstract description 4
- 230000003749 cleanliness Effects 0.000 abstract description 2
- 238000010924 continuous production Methods 0.000 abstract description 2
- 230000000754 repressing effect Effects 0.000 description 9
- 239000010453 quartz Substances 0.000 description 4
- 239000004411 aluminium Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000004925 denaturation Methods 0.000 description 1
- 230000036425 denaturation Effects 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a method for improving inclusion of vacuum refining aluminum-containing steel, which comprises the working procedures of converter/electric furnace smelting, LF refining, RH refining and continuous casting; the LF refining procedure uses lime, bauxite and quartz sand as slag materials, and the adding amount of the slag materials is controlled to be 3-5 kg/ton of steel; calcium carbide and aluminum particles are used as deoxidizing agents, and the LF refining slag is controlled to comprise the following components: caO 45-65%, siO 2 10～20%，Al 2 O 3 15-30%, feO+MnO < 1.0%, R2.5-5.0; and after the LF refining process is finished, feeding 0.1-0.4 kg of solid pure calcium cored wire per ton of steel. The method of the invention can greatly improve the control level of inclusions in the vacuum refined aluminum-containing steel, does not affect the casting performance of steel types, and meets the requirements of high cleanliness and continuous production of the vacuum refined aluminum-containing steel.
Description
Technical Field
The invention belongs to the field of ferrous metallurgy, and relates to a method for improving inclusion in vacuum refining aluminum-containing steel.
Background
The vacuum refined aluminium-containing steel is mainly aluminium-containing steel with strict requirements for inclusions and gas, and is commonly known as high-end cold heading steel series, and can be used for producing 10.9-grade and 12.9-grade high-strength fasteners, and is mainly used for high-end parts for engines and safety systems.
Because the high-end cold heading steel has extremely strict requirements on nonmetallic inclusion, in order to improve the control level of the inclusion of the steel type, the improvement capability of the process on the inclusion is limited by optimizing conventional process parameters, including means of prolonging white slag time, prolonging RH vacuum treatment time, prolonging soft blowing time, protecting casting and the like; the other type adopts a calcium-free treatment process to reduce the inclusion of the composite calcium aluminate, so that the inclusion control level can be obviously improved, but the calcium-free treatment process has severe requirements on refining slag systems and material resistance and poor casting stability, so that continuous casting cannot be performed and the popularization is poor.
Disclosure of Invention
The invention aims to provide a method for improving inclusion of vacuum refining aluminum-containing steel, which can greatly improve the control level of inclusion of vacuum refining aluminum-containing steel, does not influence the casting performance of steel types, and meets the requirements of high cleanliness and continuous production of vacuum refining aluminum-containing steel.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
a method for improving vacuum refining aluminum-containing steel inclusions comprises the working procedures of converter/electric furnace smelting, LF refining, RH refining and continuous casting; the LF refining procedure uses lime, bauxite and quartz sand as slag materials, and the adding amount of the slag materials is controlled to be 3-5 kg/ton of steel; calcium carbide and aluminum particles are used as deoxidizing agents, and the LF refining slag is controlled to comprise the following components: caO 45-65%, siO 2 10～20%，Al 2 O 3 15～30%，FeO+MnO＜1.0%，R 2.5～5.0。
Further, the LF refining process is finished, and 0.1-0.4 kg of solid pure calcium cored wire is fed to each ton of steel.
Further, after the RH refining process is started and the vacuum degree is less than or equal to 3.0kPa, lime is added into the vacuum chamber from the vacuum hopper, and the addition amount is controlled to be 0.5-2.0 kg/t per ton of steel; maintaining the pressure of the vacuum chamber to be less than or equal to 0.13kPa, and controlling the flow rate of the circulating argon to be between 0.9 and 1.0Nm per ton of steel 3 And (h) carrying out re-pressing operation for more than or equal to 15min after pure degassing, and opening to a soft blowing position for soft blowing after re-pressing, wherein the soft blowing process keeps the steelThe slag surface fluctuates but the molten steel is not exposed, and the soft blowing time is controlled to be more than or equal to 15 minutes.
Further, in the converter/electric furnace smelting process, the oxygen content of the end point is controlled to be less than or equal to 500ppm, deoxidization alloying is started when tapping is carried out 1/10, deoxidizing agent, alloy and top slag are sequentially added, molten steel is fully precipitated and deoxidized by utilizing the impact stirring effect of tapping steel flow, and meanwhile, the alloy and the top slag are fully melted; the adding amount of top slag is controlled to be 4-6 kg/ton steel.
Furthermore, the continuous casting process adopts a conventional protection casting process, so that the whole casting process is protected, and oxygen inhalation and secondary oxidation are avoided; meanwhile, a high-quality refractory material is preferable, so that foreign inclusions are reduced and no entanglement is caused.
The technical scheme of the invention is as follows:
(1) And (3) advancing the calcium treatment in the conventional process of vacuum refining aluminum-containing steel to an LF furnace process. The LF furnace adopts the conventional slag materials and deoxidizing agents such as calcium carbide, aluminum particles and the like to produce white slag, ensures the quality of the white slag, controls the alkalinity R to be 2.5-5.0, ensures FeO+MnO in the slag to be less than or equal to 1.0 percent, and feeds 0.1-0.4 kg of calcium wire into each ton of steel to carry out inclusion denaturation treatment (form low-melting-point 7 Al) 2 O 3 12 CaO) while ensuring that there is some free Ca in the steel when the LF leaves the station.
(2) When the ladle of the RH furnace is lifted, a small amount of refining slag enters the vacuum chamber along with the insertion of the dip pipe into molten steel, and the slag circulation process of the slag entering the vacuum chamber does not return to the ladle but forms a partial slag layer at the upper part of the vacuum chamber because the slag density is smaller than that of the molten steel. When the pressure of the vacuum chamber of the RH furnace is less than or equal to 3.0kPa, lime is added into the vacuum chamber by a vacuum hopper, and the lime is melted and fully and uniformly mixed with slag in the vacuum chamber to form high-alkalinity slag. The inclusion in the molten steel is captured and removed by the high-alkalinity slag in the RH circulation process, and meanwhile, free Ca in the molten steel can ensure the Al oxidized with Als in the molten steel 2 O 3 Bonding forms low melting inclusions. Because the vacuum treatment and the repressing are not carried out any more, the inclusion caused by steel slag entrainment and secondary oxidation of the molten steel due to the violent rising of the molten steel in the calcium treatment process is eliminated, and the product inclusion is greatly reduced.
The technical scheme of the invention has the following beneficial technical effects:
(1) The vacuum refined aluminum-containing steel inclusion produced by the method can reach the calcium-free treatment process level, is stable in casting, and can realize continuous casting and popularization.
(2) The vacuum refined aluminum-containing steel inclusion produced by the method can reach the following level: the class A fine system is less than or equal to 1.0, and the class A coarse system is less than or equal to 0.5; the B-class fine system is less than or equal to 1.0, and the coarse system is less than or equal to 0.5; class C fine/coarse system 0; class D fine/coarse system is less than or equal to 1.0; ds is less than or equal to 1.0.
Description of the embodiments
The technical scheme of the invention is further described in detail through examples. The Xing Ganggao end cold heading steel QSCM435-C steel type is taken as an example in each embodiment.
Example 1
The production method of the vacuum refining aluminum-containing steel QSCM435-C comprises the working procedures of converter smelting, LF refining, RH refining and continuous casting; the method comprises the following steps:
(1) Smelting in a converter: the oxygen content at the end point is 366ppm, deoxidizer, alloy and top slag are added in sequence when tapping 1/10, and the top slag is added with refined synthetic slag XGYRZ-04, and the addition amount is 4 kg/ton of steel.
(2) LF refining: after the LF furnace starts to process, slag lime, quartz and bauxite are added in batches, and the total addition amount is 5kg/t; the calcium carbide and aluminum particles are used for making white slag for full deoxidation, and the LF refining final slag comprises the following components: caO:50%, siO 2 ：10%，Al 2 O 3 :30%, feO+MnO:0.86%, r=5.0; finished product S:0.003 percent, and 0.13kg of solid pure calcium cored wire per ton of steel is fed after the treatment is finished.
(3) RH refining: after the RH furnace vacuum treatment is started, when the vacuum degree is 2.4kPa, 1.23kg of lime ton steel per ton steel is added into a vacuum chamber through a vacuum hopper; the pressure of the vacuum chamber is less than or equal to 0.13kPa, and the circulating argon flow is 0.92Nm per ton of steel 3 And (3) carrying out pure degassing for 21min, carrying out repressing, opening to a soft blowing position for soft blowing after repressing, carrying out soft blowing, carrying out slag surface fluctuation through Cheng Gang without exposing molten steel, and leaving the station after 18 min.
(4) Continuous casting: and the whole casting process is protected, and the casting process is stable.
The results of the vacuum refining of the aluminum-containing steel QSCM435-C rolled wire rods of this example were rated for nonmetallic inclusion according to GB/T10561-2005 and are shown in Table 1.
Example 2
The production method of the vacuum refining aluminum-containing steel QSCM435-C comprises the working procedures of converter smelting, LF refining, RH refining and continuous casting; the method comprises the following steps:
(1) Smelting in a converter: the oxygen content at the end point is 439ppm, deoxidizer, alloy and top slag are added in sequence when tapping 1/10, and the top slag is added with refined synthetic slag XGYRZ-04, and the addition amount is 6 kg/ton of steel.
(2) LF refining: after the LF furnace starts to process, slag lime, quartz and bauxite are added in batches, and the total addition amount is 3kg/t; the calcium carbide and aluminum particles are used for making white slag for full deoxidation, and the LF refining final slag comprises the following components: caO:65%, siO 2 ：16%，Al 2 O 3 :15%, feO+MnO:0.55%, r=4.0; finished product S:0.002%, and 0.4 kg/ton steel of solid pure calcium cored wire is fed after the treatment.
(3) RH refining: after the RH furnace vacuum treatment is started, 0.5kg of lime ton steel per ton steel is added into the vacuum chamber through the vacuum hopper when the vacuum degree is 2.9 kPa; the pressure of the vacuum chamber is less than or equal to 0.13kPa, and the circulating argon flow is 1.0Nm per ton of steel 3 And (3) carrying out pure degassing for 19min for repressing, opening to a soft blowing position for soft blowing after repressing, and leaving the station after 20min after soft blowing is carried out and Cheng Gang slag surface fluctuation is carried out without exposing molten steel.
(4) Continuous casting: and the whole casting process is protected, and the casting process is stable.
In this example, nonmetallic inclusion was rated according to GB/T10561-2005 after vacuum refining of aluminum-containing steel QSCM435-C rolled wire rods, and the results are shown in Table 1.
Example 3
The production method of the vacuum refining aluminum-containing steel QSCM435-C comprises the working procedures of converter smelting, LF refining, RH refining and continuous casting; the method comprises the following steps:
(1) Smelting in a converter: the oxygen content at the end point is 390ppm, deoxidizer, alloy and top slag are added in sequence when tapping 1/10, and the top slag is added with refined synthetic slag XGYRZ-04, and the addition amount is 5 kg/ton of steel.
(2) LF refining: after the LF furnace starts to process, slag lime, quartz and bauxite are added in batches, and the total addition amount is 3.2kg/t; the calcium carbide and aluminum particles are used for making white slag for full deoxidation, and the LF refining final slag comprises the following components: caO:45%, siO 2 ：18%，Al 2 O 3 :24%, feO+MnO:0.98%, r=2.5; finished product S:0.004%, and 0.10 kg/ton of solid pure calcium cored wire is fed after the treatment.
(3) RH refining: after the RH furnace vacuum treatment is started, when the vacuum degree is 2.9kPa, 2.0kg of lime ton steel per ton steel is added into a vacuum chamber through a vacuum hopper; the pressure of the vacuum chamber is less than or equal to 0.13kPa, and the circulating argon flow is 0.9Nm per ton of steel 3 And (3) carrying out pure degassing for 15min, carrying out repressing, opening to a soft blowing position for soft blowing after repressing, carrying out soft blowing, carrying out slag surface fluctuation through Cheng Gang without exposing molten steel, and leaving the station after 23 min.
(4) Continuous casting: and the whole casting process is protected, and the casting process is stable.
The results of the vacuum refining of the aluminum-containing steel QSCM435-C rolled wire rods of this example were rated for nonmetallic inclusion according to GB/T10561-2005 and are shown in Table 1.
Example 4
The production method of the vacuum refining aluminum-containing steel QSCM435-C comprises the working procedures of converter smelting, LF refining, RH refining and continuous casting; the method comprises the following steps:
(1) Smelting in a converter: the oxygen content at the end point is 424ppm, deoxidizer, alloy and top slag are added in sequence when tapping 1/10, and the top slag is added with refined synthetic slag XGYRZ-04, the adding amount is 3.8 kg/ton steel.
(2) LF refining: after the LF furnace starts to process, slag lime, quartz and bauxite are added in batches, and the total addition amount is 3.9kg/t; the calcium carbide and aluminum particles are used for making white slag for full deoxidation, and the LF refining final slag comprises the following components: caO:56%, siO2:20%, al 2 O 3 :18%, feO+MnO:0.75%, r=2.8; finished product S:0.003 percent, and 0.2kg of solid pure calcium cored wire per ton of steel is fed after the treatment is finished.
(3) RH refining: after the RH furnace vacuum treatment is started, when the vacuum degree is 2.9kPa, lime 1 kg/ton of steel is added into a vacuum chamber through a vacuum hopper; the pressure of the vacuum chamber is less than or equal to 0.13kPa, and the circulating argon flow is 0.95Nm per ton of steel 3 And (3) carrying out pure degassing for 20min, carrying out repressing, opening to a soft blowing position after repressing, carrying out soft blowing, carrying out fluctuation on the slag surface of Cheng Gang without exposing molten steel, and leaving the station after 15min.
(4) Continuous casting: and the whole casting process is protected, and the casting process is stable.
The nonmetallic inclusion rating after vacuum refining of the aluminum-containing steel QSCM435-C rolled wire rods in this example was in accordance with GB/T10561-2005, and the results are shown in Table 1.
Table 1 results of grading inclusions in vacuum refined aluminum-containing steel for various examples
。
Claims (6)
1. A method for improving vacuum refining aluminum-containing steel inclusions comprises the working procedures of converter/electric furnace smelting, LF refining, RH refining and continuous casting, and is characterized in that: the LF refining procedure uses lime, bauxite and quartz sand as slag materials, and the adding amount of the slag materials is controlled to be 3-5 kg/ton of steel; calcium carbide and aluminum particles are used as deoxidizing agents, and the LF refining slag is controlled to comprise the following components: caO 45-65%, siO 2 10～20%，Al 2 O 3 15～30%，FeO+MnO＜1.0%，R 2.5～5.0。
2. The method for improving inclusion of aluminum-containing steel by vacuum refining according to claim 1, wherein the end of the LF refining procedure is fed with solid pure calcium cored wire 0.1-0.4 kg/ton steel.
3. The method for improving inclusion in aluminum-containing steel by vacuum refining according to claim 1, wherein after the RH refining process is started and vacuum treatment is performed, lime is added into a vacuum chamber from a vacuum hopper when vacuum degree is less than or equal to 3.0kPa, and the addition amount is controlled to be 0.5-2.0 kg/t per ton of steel; maintaining the pressure of the vacuum chamber to be less than or equal to 0.13kPa, and controlling the flow rate of the circulating argon to be between 0.9 and 1.0Nm per ton of steel 3 And (3) carrying out re-pressing operation on the pure degassing for more than or equal to 15min, opening to a soft blowing position for soft blowing after re-pressing, wherein the soft blowing process keeps the fluctuation of the slag surface of the steel but does not expose molten steel, and the soft blowing time is controlled to be more than or equal to 15min.
4. The method for improving the inclusion of the vacuum refined aluminum-containing steel according to claim 1, wherein the converter/electric furnace smelting process is characterized in that the oxygen content of a terminal point is controlled to be less than or equal to 500ppm, deoxidization alloying is started when tapping is carried out 1/10, deoxidizing agent, alloy and top slag are sequentially added, molten steel is fully precipitated and deoxidized by utilizing the impact stirring effect of a tapping steel flow, and meanwhile, the alloy and the top slag are fully melted; the adding amount of top slag is controlled to be 4-6 kg/ton steel.
5. The method for improving vacuum refining aluminum-containing steel inclusions according to claim 1, wherein the continuous casting process protects casting throughout.
6. A method for improving vacuum refining aluminum-containing steel inclusions as claimed in claim 1, wherein the vacuum refining aluminum-containing steel inclusion levels produced by the method are as follows: the class A fine system is less than or equal to 1.0, and the class A coarse system is less than or equal to 0.5; the B-class fine system is less than or equal to 1.0, and the coarse system is less than or equal to 0.5; class C fine/coarse system 0; class D fine/coarse system is less than or equal to 1.0; ds is less than or equal to 1.0.
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