CN103215409A - Smelting method for refining steel grains by using magnesium-aluminum modified inclusion - Google Patents
Smelting method for refining steel grains by using magnesium-aluminum modified inclusion Download PDFInfo
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- CN103215409A CN103215409A CN2012103156084A CN201210315608A CN103215409A CN 103215409 A CN103215409 A CN 103215409A CN 2012103156084 A CN2012103156084 A CN 2012103156084A CN 201210315608 A CN201210315608 A CN 201210315608A CN 103215409 A CN103215409 A CN 103215409A
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- 239000010959 steel Substances 0.000 title claims abstract description 183
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 182
- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000003723 Smelting Methods 0.000 title claims abstract description 18
- 238000007670 refining Methods 0.000 title abstract description 9
- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 title abstract 2
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 45
- 239000011777 magnesium Substances 0.000 claims abstract description 43
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000001301 oxygen Substances 0.000 claims abstract description 40
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 34
- 230000004048 modification Effects 0.000 claims abstract description 32
- 238000012986 modification Methods 0.000 claims abstract description 32
- 230000008569 process Effects 0.000 claims abstract description 31
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 27
- 239000011029 spinel Substances 0.000 claims abstract description 23
- 229910052596 spinel Inorganic materials 0.000 claims abstract description 23
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 20
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 18
- QENHCSSJTJWZAL-UHFFFAOYSA-N magnesium sulfide Chemical compound [Mg+2].[S-2] QENHCSSJTJWZAL-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000007711 solidification Methods 0.000 claims abstract description 8
- 230000008023 solidification Effects 0.000 claims abstract description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 49
- 239000000395 magnesium oxide Substances 0.000 claims description 24
- 229910001051 Magnalium Inorganic materials 0.000 claims description 21
- 239000004411 aluminium Substances 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 21
- GANNOFFDYMSBSZ-UHFFFAOYSA-N [AlH3].[Mg] Chemical compound [AlH3].[Mg] GANNOFFDYMSBSZ-UHFFFAOYSA-N 0.000 claims description 19
- 239000005864 Sulphur Substances 0.000 claims description 17
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 11
- 238000002425 crystallisation Methods 0.000 claims description 11
- 230000008025 crystallization Effects 0.000 claims description 11
- 238000002203 pretreatment Methods 0.000 claims description 11
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 6
- MHKWSJBPFXBFMX-UHFFFAOYSA-N iron magnesium Chemical compound [Mg].[Fe] MHKWSJBPFXBFMX-UHFFFAOYSA-N 0.000 claims description 6
- 229910000954 Medium-carbon steel Inorganic materials 0.000 claims description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims 1
- 239000013078 crystal Substances 0.000 abstract description 7
- 229910052717 sulfur Inorganic materials 0.000 abstract description 7
- 239000011593 sulfur Substances 0.000 abstract description 5
- -1 magnesium aluminate Chemical class 0.000 abstract description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 abstract 2
- 239000000126 substance Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 11
- 238000005096 rolling process Methods 0.000 description 8
- 238000009628 steelmaking Methods 0.000 description 8
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- 238000005275 alloying Methods 0.000 description 6
- 238000009749 continuous casting Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000005728 strengthening Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 229910052593 corundum Inorganic materials 0.000 description 4
- 229910001845 yogo sapphire Inorganic materials 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 230000009975 flexible effect Effects 0.000 description 3
- 229910052755 nonmetal Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 230000002787 reinforcement Effects 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- CQBLUJRVOKGWCF-UHFFFAOYSA-N [O].[AlH3] Chemical compound [O].[AlH3] CQBLUJRVOKGWCF-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- HLYCTXRRGDDBOW-UHFFFAOYSA-N 2-methylpiperazine-1-carbodithioic acid Chemical compound CC1CNCCN1C(S)=S HLYCTXRRGDDBOW-UHFFFAOYSA-N 0.000 description 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910019092 Mg-O Inorganic materials 0.000 description 1
- 229910019094 Mg-S Inorganic materials 0.000 description 1
- 229910019395 Mg—O Inorganic materials 0.000 description 1
- 229910019397 Mg—S Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 238000009845 electric arc furnace steelmaking Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000007663 fining method Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 210000001161 mammalian embryo Anatomy 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- NHDHVHZZCFYRSB-UHFFFAOYSA-N pyriproxyfen Chemical compound C=1C=CC=NC=1OC(C)COC(C=C1)=CC=C1OC1=CC=CC=C1 NHDHVHZZCFYRSB-UHFFFAOYSA-N 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 229910000658 steel phase Inorganic materials 0.000 description 1
- 238000012932 thermodynamic analysis Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
A smelting method for refining steel grains by using magnesium-aluminum modified inclusion is used for treating molten steel produced by secondary refining and comprises the following steps: a pretreatment step, adding aluminum into the molten steel to react with oxygen and sulfur in the molten steel until the total oxygen content of the molten steel is reduced to 15-120 ppm and the sulfur content is reduced to 15-150 ppm, and generating aluminum oxide 2O3) So as to obtain cleaner molten steel; and a modification step of adding magnesium into the clean molten steel to make magnesium and residual oxygen, sulfur and aluminum oxide (Al) in the clean molten steel2O3) And reacting until the total oxygen content of the molten steel is 10-60 ppm and the sulfur content is 5-100 ppm, generating fine inclusions such as magnesium aluminate spinel, magnesium sulfide and the like, and taking the precipitated inclusions as crystal nuclei in the subsequent solidification process of the molten steel to generate fine-grained steel.
Description
Technical field
The present invention relates to a kind of iron and steel smelting process, particularly a kind of with the inclusion (inclusion) of magnalium modification (modify) in the molten steel of secondary refining, and then the smelting process of refinement crystalline grain of steel.
Background technology
The molten steel smelted of converter process (Converter Steelmaking), electrical furnace steelmaking process (EAF) now, usually carry out secondary refining through processing procedures such as LF, VD, RH, VOD, VAD, expect thus the content of the phosphorus in the molten steel, sulphur, oxygen, nitrogen, hydrogen is further reduced, the content adjustment of carbon and alloy is reasonable, make the component content in the molten steel of institute's output be adjusted to ideal range, to meet the steel product demand of the various different qualities of modern tool.
Tradition steel-making processing procedure roughly is divided into steps such as electric-arc furnace steelmaking S91 or converter steelmaking S91 ' and secondary concise (Secondary Refining) S93 (with reference to shown in Figure 1), wherein, in converter steelmaking or Electric furnace steel making step S91, S91 ', can carry out carbonization treatment to molten steel by being blown into oxygen, generate gases such as carbon monoxide or carbonic acid gas and discharge; At this moment, the molten steel total oxygen content of output (oxygen in dissolved oxygen and the oxide compound) is higher, inclusion is more, is cast into steel ingot if directly will contain the molten steel of excess of oxygen, then can reduce the quality of steel.By the concise step S92 of various secondary, molten steel is carried out secondary refining (for example: deoxidation, desulfurization, the degassing, carbon drop etc.), and via the molten steel of secondary refining step S92, quality is highly improved, in continuous casting, be cast into the steel embryo, again through steel rolling operation and the output steel work.
Yet, in now scientific and technological flourish under, hard-core technology is very harsh for the specification of quality of steel work, so that at present except being the main developing goal with the peace and quiet Clean Steel of height, more expectation further promotes the performance of Clean Steel, and more high strength and the more steel of high tenacity are provided in development, and will research and develop the improvement that emphasis focuses on molten steel characteristic behind the concise step S92 of secondary, the super-steel (particularly steel plate) that intensity surpasses 1000Mpa is subdued in exploitation, with the demand in response to market.
Therefore, according to the material reinforcement principle, many at present with refined crystalline strengthening (grain refining strengthening), solid molten (solid solution strengthening), precipitation strength (precipitation strengthening), second reinforcement modes such as (secondary strengthening) strengthened, directly improve the grain structure and the arrangement of steel, to improve the strength of materials of steel.Wherein, can pass through an Alloying Treatment step S93, make an addition in the molten steel after secondary is concise, strengthen intensity, toughness and other speciality of steel by solid molten reinforcement, precipitation strength mode to contain alloying element (for example: chromium, manganese, nickel, rare earth etc.); Perhaps, utilize a hot machine treatment step S94(also to claim cooling controlling and rolling controlling process, TCMP) crystal grain thinning, to secondary concise-steel billet of continuous casting, temperature, cooling conditions and the roll speed etc. that in rolling process, heat by the control steel, make steel in course of hot rolling according to the processing procedure circuit phase transformation of setting, forms thinner grain structure (crystal grain 5 ~ 10 μ m usually), reach the lifting hardness of steel, improve the flexible purpose.
The operation of above-mentioned those existing methods not only cost is higher and limited to the performance boost amplitude, with the alloying process is example, need according to other expensive alloying elements auxiliary, could strengthen the performances such as intensity of steel, make the speciality of the obvious limited alloying element of lifting of steel strength itself, and cause operating cost higher, and the amplitude that promotes of steel performance is no more than 20%(usually and subdues intensity and be no more than 600Mpa); In addition, with hot machine treatment process is example, can produce the High Strength Steel of subduing intensity 700 ~ 900Mpa, but must be in the operation process of controlled rolling and controlled cooling, the various conditions of rigorous control steel phase transformation, for example, Heating temperature, roll speed or speed of cooling etc. can accurately be finished the refinement of steel crystal grain, so need to drop into a huge sum of money and carry out the equipment enlarging, and energy consumption cost is huge during operation, so that this hot machine treatment process popularization is restricted.
In view of this, be necessary to develop a kind of crystal fining method that is applicable to through the molten steel of the concise institute of secondary output really,, create conditions for solving aforesaid problem by the interaction between magnalium and molten steel.
Prior art
S91 electric arc furnace step S91 ' oxygen coverter step
The concise step S93 alloying of S92 secondary step
The hot machine treatment step of S94
Summary of the invention
Main purpose of the present invention is improved above-mentioned shortcoming, so that a kind of smelting process with magnalium modification inclusion refinement crystalline grain of steel to be provided, it is the inclusion in the molten steel of the concise back of modification secondary directly, with when improving steel cleanness, utilize the molten steel thermodynamic condition,, improve the quantity of fine crystalline nuclear in the steel by changing composition of fluid inclusions, size, form, distribution, promote the refinement of crystalline grain of steel, and then promote the intensity and the toughness of steel.
Another object of the present invention is, provides a kind of with magnalium modification inclusion, and then the smelting process of refinement crystalline grain of steel, can reduce the required cost that expends of operation process, improves the performance of steel.
For reaching aforementioned goal of the invention, the present invention is with magnalium modification inclusion, and then the smelting process of refinement crystalline grain of steel, in order to handle molten steel, comprise through the concise institute of secondary output: a pre-treatment step, add aluminium in this molten steel, make oxygen, reaction of Salmon-Saxl in aluminium and this molten steel, total oxygen content until this molten steel is reduced to 15 ~ 120ppm, and sulphur content is reduced to 15 ~ 150ppm, and generates aluminium sesquioxide (Al
2O
3), and obtain than clean molten steel; And a modification step, add magnesium in this molten steel, make in magnesium and this molten steel remaining oxygen, sulphur and aluminium sesquioxide (Al
2O
3) reaction, whole oxygen amount until molten steel is 10 ~ 60ppm, sulphur content is 5 ~ 100ppm, and (fusing point is higher than 2000 ℃ to generate magnesium-aluminium spinel, particulate state, the overwhelming majority are of a size of: 0 ~ 3 μ m, most of about 1 μ m), inclusion such as magnesium sulfide (particulate state, high-melting-point, help to purify crystal boundary), these non-metallic inclusions are solid-state and are uniformly distributed in the molten steel, difficult gathering is grown up, in continuous casting and rolling process subsequently, these inclusions of separating out generate fine grained steel as the nuclei of crystallization of this molten steel solidification process.
In this modification procedure, the addition of magnesium is to be added with 0.01 ~ 0.6 kilogram in the molten steel per ton.And, in clean molten steel, feed magnesium-iron alloy line especially, and the Mg content of this magnesium-iron alloy line is 5 ~ 80%.
Wherein, the process temperatures of this pre-treatment step and modification procedure is 1843 ~ 1903K(1873 ± 30K).And, be medium carbon steel or soft steel through the molten steel of the concise output of secondary.
Description of drawings
Fig. 1 is existing steelmaking process synoptic diagram.
Fig. 2 is a schematic flow sheet of the present invention.
Fig. 3 is the thermodynamic(al)equilibrium figure of oxygen-aluminium of the present invention.
Fig. 4 is Mg-Al-magnesium-aluminium spinel of the present invention and MgO-Al
2O
3The thermodynamic(al)equilibrium figure of-magnesium-aluminium spinel.
Fig. 5 is the thermodynamic(al)equilibrium figure of aluminium-magnesium of the present invention.
Fig. 6 is magnesium-oxygen of the present invention and magnesium-Al
2O
3Thermodynamic(al)equilibrium figure.
Fig. 7 generates the phasor of magnesium-aluminium spinel for the present invention.
Description of reference numerals
The present invention
S1 pre-treatment step S2 modification procedure
Embodiment
Purpose for a better understanding of the present invention, feature and advantage are elaborated to preferred embodiment of the present invention below in conjunction with accompanying drawing.
As shown in Figure 2, it is a preferred embodiment of the present invention, and system comprises a pre-treatment step S1 and a modification step S2 with the smelting process of magnalium modification inclusion refinement crystalline grain of steel.Wherein, the present invention is with the smelting process of magnalium modification inclusion refinement crystalline grain of steel, and in order to handle the molten steel through the concise institute of secondary output, when below in detail each step being described in detail, with the molten steel of " molten steel " representative after the concise tapping of secondary, promptly what is called has the molten steel of higher cleaning.
What note is, under the accurate state of Δ G θ index shown in each chemical formula of the following stated through the free energy change of chemical reaction; The activity of each element under the accurate state of a index.
This pre-treatment step S 1 adds aluminium in this molten steel, make oxygen, reaction of Salmon-Saxl in aluminium and this molten steel, and the total oxygen content in this molten steel is reduced to 15 ~ 120ppm, and sulphur content is 15 ~ 150ppm, and generates aluminium sesquioxide (Al
2O
3), and obtain clean molten steel.In detail, aluminium is the common reductor of steel-making processing procedure, because of aluminium has preferable deoxidizing capacity, with the oxygen in the molten steel being reduced to extremely low standard, and learn according to the thermodynamic(al)equilibrium principle, when the aluminium addition in the molten steel increases gradually, can decrease the oxygen level in the molten steel, make aluminium and oxygen effect and generate aluminium sesquioxide Al
2O
3(shown in chemical formula one), and the total oxygen content that reduces simultaneously in the molten steel is preferable to 15 ~ 120ppm, and under aluminium, sulphur influence each other, make the sulphur content in the molten steel be reduced to 15 ~ 150ppm roughly in the lump, and obtain to contain numerous Al
2O
3Molten steel.
(chemical formula one) 2[Al]+3[O]=Al
2O
3 (s)Δ G
1 θ=-1202070+386.28T
Can calculate Al and O equilibrium relationship in the liquid by (chemical formula one) and activity theory:
[%O]
3·[%Al]
2=1.22×10
-12
Obtain Al and O thermodynamic(al)equilibrium relation in (Fig. 3) molten steel in view of the above.
For example, it is that 1843 ~ 1903K carries out this pre-treatment step S1de reactive aluminum that present embodiment is selected in temperature, special under the operative temperature of 1873K, aluminium addition: 0.02 ~ 2kg/ ton (look the total oxygen content in the molten steel that obtains and determine), make the oxygen in aluminium and the molten steel produce reaction, and generation numerous Al 2O3, with this total oxygen content in molten steel is reduced to 15 ~ 120ppm, and the sulphur content that reduces simultaneously in the molten steel is reduced to 15 ~ 150ppm, and then it is extremely low and be rich in the clean molten steel of numerous Al 2O3 to obtain to contain oxygen, sulfur content, to carry out follow-up modification procedure S2.
Has numerous Al 2O3 through what this pre-treatment step S1 obtained than purifying of steel, more easily assemble because of the Al2O3 particle this moment and grow up, so when Al2O3 produces in a large number, derive nozzle clogging and the puzzlement of the interruption that causes casting in follow-up molten steel casting process easily, so that this molten steel turns bane into boon after must entering follow-up modification procedure S2 processing again.
This modification procedure S2 adds magnesium in addition in this clean molten steel, make magnesium with should clean molten steel in remaining oxygen, sulphur and aluminium sesquioxide Al2O3 reaction, total oxygen content in this molten steel is 10 ~ 60ppm, sulphur content is 5 ~ 100ppm, and generation inclusion magnesium-aluminium spinel, magnesium sulfide and magnesium oxide, with the inclusion of separating out the nuclei of crystallization, generate fine grained steel as this molten steel solidification process.Wherein, these non-metallic inclusions (non-metallic inclusions) are solid-state and are uniformly distributed in the molten steel, and difficult gathering is grown up, in continuous casting and rolling process subsequently, just can be used as the nuclei of crystallization of molten steel, and then promote the steel solidification and crystallization, generate and change fine grained steel into.
For guaranteeing the realization of above-mentioned purpose, the spy carries out thermodynamic analysis and calculation, confirms feasibility.
Magnesium and the oxygen, the reaction of Salmon-Saxl that remain in than purifying of steel, and generate magnesium oxide and magnesium sulfide (shown in chemical formula two, three) simultaneously, and when thermodynamical reaction tends to balance gradually, with causing transforming (shown in chemical formula four) between magnesium oxide and the magnesium sulfide mutually, utilize the generation of thermodynamic condition control inclusion, and quantity, size, form etc., and obtain Mg-O; Mg-S mutual restriction and keep the balance of Mg, Al, O, S, magnesium oxide, magnesium sulfide etc.Its thermodynamic(al)equilibrium relation is as follows:
(chemical formula two) Mg(g)+[O]=MgO(s) Δ G2 θ=-614000+208.28T
Can obtain Mg and O thermodynamic(al)equilibrium relation in the molten steel according to activity theory:
a
Mg·a
O=1.31×10
-8
(chemical formula three) Mg
(g)+ [S]=MgS
(s)Δ G
3 θ=-419858.5+174.3T
Can obtain Mg and S thermodynamic(al)equilibrium relation in the molten steel according to activity theory:
a
Mg·a
S=5.79×10
-5
The more important thing is, magnesium not only can be simultaneously and aluminium, oxygen, reaction of Salmon-Saxl, also can react by the magnesium oxide that generates and than the Al2O3 that is rich in the clean molten steel, with the magnesium-aluminium spinel [MgOAl2O3] of same generation micritization (as chemical formula five, shown in six), magnesium-aluminium spinel by micritization, and the magnesium oxide of above-mentioned micritization, magnesium sulfide, just can separate out inclusion in the steel and as the steel crystallization nuclei in should clean molten steel, with in follow-up solidification and crystallization process by using, promote intracrystalline needle-like ferrite (Acicular Ferrite, be called for short AF) forming core, and then change that the steel crystalline generates and with the grain structure of this refinement steel.
(chemical formula four) MgO
(s)+ Al
2O
3 (s)→ MgOAl
2O
3 (s)
ΔG
4 θ=-35600-2.09T
Chemical formula two, tetrad be upright can be pushed away:
(chemical formula five) Mg+4O+2Al → MgOAl
2O
3 (s)
ΔG
5 θ=-1969070+623.87T
Mg, Al equilibrium relationship in the molten steel according to thermodynamic principles, obtain a free energy equation of equilibrium, suc as formula one.
Get
The:
Can obtain Fig. 4 of the present invention by above-mentioned analysis: magnesium-aluminium-magnesium-aluminium spinel and [MgO]-[Al
2O
3The thermodynamic(al)equilibrium figure of]-magnesium-aluminium spinel.
Wherein, when the thermodynamic(al)equilibrium of chemical reaction was assigned in effect when in 1873K, the relation that various inclusions transform mutually was shown in the curve among Fig. 41 and 2.
The critical condition that on behalf of magnesium oxide and magnesium-aluminium spinel, Fig. 4 curve 1 transform, meaning is promptly: after handling molten steel with magnalium, the activity a of each element is brought in the formula after the above-mentioned free energy balance, [%Al]
2/ [%Mg]
3＞2.64x10
9The time, reaction falls within the B interval under the curve 1, and the material that is generated is a magnesium-aluminium spinel; Otherwise, get [%Al]
2/ [%Mg]
3＜2.64 * 10
9The time, reaction then falls within the A interval on the curve 1, so the material that is generated then is magnesium oxide.In addition, the critical condition that on behalf of Al, Mg and magnesium-aluminium spinel, 2 of curves transform, that is: handle molten steel with magnalium after, equally the active a of each element is brought in the formula after the above-mentioned free energy balance, [%Mg]
3/ [%Al]
2＜1.5 * 10
-14The time, reaction system falls within the B interval of curve 2 tops, so the material that is generated is a magnesium-aluminium spinel; Otherwise, get [%Mg]
3/ [%Al]
2＞1.5 * 10
-14The time, reaction then falls within the C interval under the curve 2, so the material that is generated then is Al
2O
3More than, can understand easily according to the thermodynamic(al)equilibrium principle and with reference to Fig. 4 for haveing the knack of this skill person, and can obtain according to this than the appropriate reaction condition, with after magnalium adds, magnesium-aluminium spinel that can the output micritization etc. are preferable as the forming core core.
Therefore, according to thermodynamic principles, when under the 1873K effect, when having magnesium and aluminium simultaneously in the molten steel, Al
2O
3The equilibrium conditions that transforms mutually with magnesium oxide is:
(chemical formula six) 3[Mg]+Al
2O
3(s)=3MgO
(s)+ 2[Al]
ΔG
6 θ=-992130+332.76T
[Mg]
3/[Al]
2=5.1×10
-11
Cooperate with reference to shown in Figure 5, in the molten steel after handling with magnalium [Mg]
3/ [Al]
2＞5.1 * 10
-11The time, with making the Al that exists originally
2O
3Generate magnesium oxide with the Mg reaction, and make Al simultaneously
2O
3Be reduced into aluminium (shown in chemical formula six), to reduce the total oxygen content of handling in the molten steel of back.
, when operating pre-treatment step S1 of the present invention and modification procedure S2, certainly will make on aluminium in the molten steel, the curve 1 that Mg content is maintained at Fig. 5 (i.e. [Mg] to shown in Figure 7 as Fig. 5
3/ [Al]
2＞5.1 * 10
-11), and according to calculation of thermodynamics, the successive reaction after making magnalium add can fall within the B district of Fig. 6, and (curve 1 shown in Figure 6 is represented aluminium-oxygen balance; Curve 2 is represented magnesium-oxygen balance), (promptly refer to Al with the formation condition that satisfies magnesium-aluminium spinel shown in Figure 7
2O
3/ MgO ratio is 20 ~ 29%), can make magnesium, oxygen and magnesium, Al
2O
3Produce reaction simultaneously, separate out inclusion in the steel (comprising the magnesium sulfide that chemical formula two generates) thus with the magnesium oxide that generates micritization and magnesium-aluminium spinel, as the steel crystallization nuclei in this clean molten steel, these non-metallic inclusions are solid-state and are uniformly distributed in the molten steel, difficult gathering is grown up, in continuous casting and rolling process subsequently, just can be used as the nuclei of crystallization of molten steel, to promote the forming core of intracrystalline needle-like ferrite, and then promote the steel solidification and crystallization, reach refinement crystalline grain of steel tissue and promote hardness of steel and flexible purpose.
For example, present embodiment is especially under the operative temperature of 1873K, add 0.01 ~ 0.6 kilogram MAGNESIUM METAL in 1 ton than purifying of steel in, select especially in clean molten steel, to feed magnesium-iron alloy line, and the Mg content of this magnesium-iron alloy line is preferably 5 ~ 80%, magnesium and undissolved oxygen, sulphur react, and then generate magnesium oxide and magnesium sulfide, and are subject to thermodynamic(al)equilibrium principle mutual restriction; Simultaneously, the magnesium oxide of above-mentioned generation more can be further and Al
2O
3Reaction generates magnesium-aluminium spinel, and according to thermodynamic(al)equilibrium principle (as shown in Figure 4), and the generation of restriction micritization magnesium-aluminium spinel so that the total oxygen content in the molten steel is reduced to 10 ~ 60ppm, and reduces sulphur content to the 5 ~ 100ppm in the molten steel simultaneously.So, with can be according to the thermodynamic(al)equilibrium principle, the nonmetal oxide matter such as magnesium oxide, magnesium sulfide and magnesium-aluminium spinel that make above-mentioned generation, be and evenly, do not assemble and dispergated distribution, and make the crystal grain great majority of those nonmetal oxide matter less than below 3 millimeters, as the nuclei of crystallization of this solidification of molten steel, promote the forming core of intracrystalline needle-like ferrite to separate out inclusion, make the crystalline grain of steel refinement; Even, because of the high-angle boundary between the intracrystalline ferrite, and when making the texture of tiny crack in the steel cross over the intracrystalline ferrite easily, promote the refinement of crystalline grain of steel with this deflection, improve the intensity and the toughness of steel thus, subdue the steel that intensity surpasses 1000Mpa and can be used for developing.
In sum, the present invention is with the smelting process principal character of magnalium modification inclusion refinement crystalline grain of steel: add as basic reductor with aluminium, tentatively in pre-treatment step S1 behind the dissolved oxygen, add by the MAGNESIUM METAL among this modification procedure S2 again, effect with remaining oxygen, sulphur in the molten steel of increase and cleaning, force according to thermodynamic principles under felicity condition, generate nonmetal oxides such as magnesium oxide and magnesium sulfide, not only reduce oxygen, sulphur content in the molten steel, reach the effect of preferable deoxidation and desulfurization; Even, the magnesium oxide after the dissolving also can with (Al
2O
3) mutual restriction, to generate the magnesium-aluminium spinel of eutectic kenel, be dispersed evenly to molten steel this moment and endlessly assemble and grow up, magnesium-aluminium spinel, magnesium sulfide and magnesium oxide, in continuous casting and rolling process subsequently, the inclusion of separating out in these molten steel is as the heterogeneous body forming core core of steel, promote the generation of intracrystalline ferrite and change the crystalline form of steel, effectively cutting apart and the grain structure of refinement steel, and then improve the performance of steel, reach effects such as the intensity that improves steel and toughness.
The present invention is with the direct molten steel inclusion of modification secondary after concise of the smelting process of magnalium modification inclusion refinement crystalline grain of steel, with when improving steel cleanness, utilize the molten steel thermodynamic condition to change composition of fluid inclusions, size, form, distribution, improve the quantity of fine crystalline nuclear in the steel, finishing the refinement of crystalline grain of steel, and then reach and promote hardness of steel and flexible effect.
The present invention can reduce the required cost that expends of operation process with the smelting process of magnalium modification inclusion refinement crystalline grain of steel, and can improve the performance of steel thus.
The above just describes the present invention in detail by preferred embodiment; but should not limit the scope of patent working of the present invention with this; one of ordinary skill in the art are not breaking away under the spirit and scope of the present invention; equivalent variations and improvement that described relatively embodiment carries out all should belong to the technical scope that the present invention protects.
Claims (5)
1. the smelting process with magnalium modification inclusion refinement crystalline grain of steel in order to handle the molten steel through the concise institute of secondary output, is characterized in that, comprises:
A pre-treatment step adds aluminium in this molten steel, make oxygen, reaction of Salmon-Saxl in aluminium and this molten steel, is 15 ~ 120ppm until the total oxygen content of this molten steel, and sulphur content is 15 ~ 150ppm, and generates aluminium sesquioxide, and obtains clean molten steel; And
A modification procedure, in this clean molten steel, add magnesium in addition, make magnesium with should clean molten steel in remaining oxygen, sulphur and aluminium sesquioxide reaction, total oxygen content until this molten steel is 10 ~ 60ppm, sulphur content is 5 ~ 100ppm, and generate inclusion magnesium oxide, magnesium sulfide and magnesium-aluminium spinel, with the inclusion of separating out the nuclei of crystallization, and generate fine grained steel as this molten steel solidification process.
2. the smelting process with magnalium modification inclusion refinement crystalline grain of steel according to claim 1 is characterized in that, in this modification procedure, the addition of magnesium is to be added with 0.01 ~ 0.6 kilogram in the molten steel per ton.
3. the smelting process with magnalium modification inclusion refinement crystalline grain of steel according to claim 1 and 2 is characterized in that, in this modification procedure, feed magnesium-iron alloy line in clean molten steel, and the Mg content of this magnesium-iron alloy line is 5 ~ 80%.
4. the smelting process with magnalium modification inclusion refinement crystalline grain of steel according to claim 1 and 2 is characterized in that the process temperatures of this pre-treatment step and modification procedure is 1843 ~ 1903K.
5. the smelting process with magnalium modification inclusion refinement crystalline grain of steel according to claim 1 and 2 is characterized in that, is medium carbon steel or soft steel through the molten steel of the concise output of secondary.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW100147429A TWI464271B (en) | 2011-12-20 | 2011-12-20 | A metallurgical method by adding mg-al to modify the inclusions and grain refinement of steel |
| TW100147429 | 2011-12-20 |
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| Publication Number | Publication Date |
|---|---|
| CN103215409A true CN103215409A (en) | 2013-07-24 |
| CN103215409B CN103215409B (en) | 2015-10-07 |
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|---|---|---|---|
| CN201210315608.4A Expired - Fee Related CN103215409B (en) | 2011-12-20 | 2012-08-30 | Smelting method for refining steel grains by using magnesium-aluminum modified inclusion |
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| Country | Link |
|---|---|
| US (1) | US20130152740A1 (en) |
| JP (1) | JP5526437B2 (en) |
| CN (1) | CN103215409B (en) |
| TW (1) | TWI464271B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108531760A (en) * | 2018-04-17 | 2018-09-14 | 青岛科技大学 | A kind of new application of magnesium aluminate spinel |
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| CN1113660A (en) * | 1993-08-16 | 1995-12-20 | 新日本制铁株式会社 | Steel containing ultrafine oxide inclusions dispersed therein |
| JP2001303191A (en) * | 2000-04-19 | 2001-10-31 | Nippon Steel Corp | Ultrahigh strength steel pipe for line pipe, excellent in haz toughness in weld zone, and its manufacturing method |
| JP2003027180A (en) * | 2001-07-18 | 2003-01-29 | Nippon Steel Corp | Cast slab of high carbon steel with fine solidification structure and pearlite transformation structure |
| CN1631578A (en) * | 1999-04-08 | 2005-06-29 | 新日本制铁株式会社 | Cast steel and steel material with excellent workability, method for processing molten steel therefor and method for manufacturing the cast steel and steel material |
| CN101392308A (en) * | 2007-09-22 | 2009-03-25 | 鞍钢股份有限公司 | Molten steel deoxidation method for refining solidification structure |
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| JP4287974B2 (en) * | 2000-03-27 | 2009-07-01 | 新日本製鐵株式会社 | Method for processing molten steel with finely solidified structure characteristics |
| JP4283434B2 (en) * | 2000-01-31 | 2009-06-24 | 新日本製鐵株式会社 | Treatment method of molten steel with excellent solidification structure characteristics |
| JP4265066B2 (en) * | 2000-02-02 | 2009-05-20 | 三菱電機株式会社 | Multiple power system interchange control means |
| JP3746045B2 (en) * | 2002-03-27 | 2006-02-15 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel slabs and steel plates and methods for producing them |
| JP4430284B2 (en) * | 2002-07-23 | 2010-03-10 | 新日本製鐵株式会社 | Steel material with few alumina clusters |
| JP4022190B2 (en) * | 2003-09-12 | 2007-12-12 | 新日本製鐵株式会社 | Method of adding rare earth elements to molten steel |
| JP2008266706A (en) * | 2007-04-19 | 2008-11-06 | Nisshin Steel Co Ltd | Method for continuously casting ferritic stainless steel slab |
-
2011
- 2011-12-20 TW TW100147429A patent/TWI464271B/en not_active IP Right Cessation
-
2012
- 2012-08-28 JP JP2012187196A patent/JP5526437B2/en not_active Expired - Fee Related
- 2012-08-30 CN CN201210315608.4A patent/CN103215409B/en not_active Expired - Fee Related
- 2012-09-07 US US13/606,500 patent/US20130152740A1/en not_active Abandoned
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1113660A (en) * | 1993-08-16 | 1995-12-20 | 新日本制铁株式会社 | Steel containing ultrafine oxide inclusions dispersed therein |
| CN1631578A (en) * | 1999-04-08 | 2005-06-29 | 新日本制铁株式会社 | Cast steel and steel material with excellent workability, method for processing molten steel therefor and method for manufacturing the cast steel and steel material |
| JP2001303191A (en) * | 2000-04-19 | 2001-10-31 | Nippon Steel Corp | Ultrahigh strength steel pipe for line pipe, excellent in haz toughness in weld zone, and its manufacturing method |
| JP2003027180A (en) * | 2001-07-18 | 2003-01-29 | Nippon Steel Corp | Cast slab of high carbon steel with fine solidification structure and pearlite transformation structure |
| CN101392308A (en) * | 2007-09-22 | 2009-03-25 | 鞍钢股份有限公司 | Molten steel deoxidation method for refining solidification structure |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108531760A (en) * | 2018-04-17 | 2018-09-14 | 青岛科技大学 | A kind of new application of magnesium aluminate spinel |
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| Publication number | Publication date |
|---|---|
| US20130152740A1 (en) | 2013-06-20 |
| JP2013129906A (en) | 2013-07-04 |
| TWI464271B (en) | 2014-12-11 |
| CN103215409B (en) | 2015-10-07 |
| TW201326409A (en) | 2013-07-01 |
| JP5526437B2 (en) | 2014-06-18 |
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