CN115572790B - Method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by vacuum induction furnace - Google Patents
Method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by vacuum induction furnace Download PDFInfo
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 120
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 67
- 238000000034 method Methods 0.000 title claims abstract description 39
- 238000003723 Smelting Methods 0.000 title claims abstract description 28
- 230000006698 induction Effects 0.000 title claims abstract description 22
- 239000010935 stainless steel Substances 0.000 title claims abstract description 17
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 17
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 95
- 239000010959 steel Substances 0.000 claims abstract description 95
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 35
- 239000000956 alloy Substances 0.000 claims abstract description 35
- RRZKHZBOZDIQJG-UHFFFAOYSA-N azane;manganese Chemical compound N.[Mn] RRZKHZBOZDIQJG-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 24
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 24
- 238000010079 rubber tapping Methods 0.000 claims abstract description 24
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000007670 refining Methods 0.000 claims abstract description 21
- 238000005275 alloying Methods 0.000 claims abstract description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052786 argon Inorganic materials 0.000 claims abstract description 11
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 9
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 8
- 230000023556 desulfurization Effects 0.000 claims abstract description 8
- 238000009826 distribution Methods 0.000 claims abstract description 7
- 238000003892 spreading Methods 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims description 15
- 230000008018 melting Effects 0.000 claims description 15
- 229920006395 saturated elastomer Polymers 0.000 claims description 10
- 238000005121 nitriding Methods 0.000 claims description 4
- 238000007792 addition Methods 0.000 description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 239000000203 mixture Substances 0.000 description 10
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 239000007791 liquid phase Substances 0.000 description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 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 4
- 239000000463 material Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- 229910001199 N alloy Inorganic materials 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 229910001309 Ferromolybdenum Inorganic materials 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/005—Manufacture of stainless steel
-
- 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
- C21C7/0006—Adding metallic additives
-
- 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
- C21C7/0025—Adding carbon material
-
- 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
-
- 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
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- 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
- Y02P10/25—Process efficiency
Abstract
The invention discloses a method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by a vacuum induction furnace, which comprises the processes of charging, vacuum heating, refining and deoxidizing, alloying and nitrogen-controlling tapping; the charging process comprises the following steps: calculating carbon distribution amount according to the C content requirement in steel, and spreading carbon powder at the bottom of a crucible during charging; the refining deoxidizing process comprises the following steps: adding rare earth after refining is finished to carry out deep deoxidation and desulfurization; the alloying process comprises the following steps: during alloying, argon is filled into the furnace; the nitrogen control tapping process comprises the following steps: adding manganese nitride alloy in the nitrogen-control tapping process, wherein the adding amount of the manganese nitride alloy is calculated according to the nitrogen increasing amount of molten steel, and the yield of the manganese nitride alloy is calculated according to the formula (I). The method not only ensures the stability of the components of the low-nitrogen stainless steel product, but also can accurately control the nitrogen content in the steel, fully plays the characteristics of the vacuum induction furnace, can accurately calculate the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of the molten steel, and controls the deviation within 5% of the target nitrogen content.
Description
Technical Field
The invention relates to a vacuum induction smelting method, in particular to a method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by a vacuum induction furnace.
Background
In recent years, nitrogen has become an important alloying element of nickel-chromium austenitic stainless steel, and alloying of nitrogen can greatly improve alloy strength without damaging plasticity and toughness, so that high-strength and high-toughness stainless steel can be developed. Microalloying stainless steel with nitrogen is becoming more and more important.
The vacuum induction furnace is used as the most common smelting equipment for steel grade development, and the nitrogen increasing process of smelting the nitrogen-containing stainless steel is operated under a certain vacuum condition, so that the nitrogen partial pressure is small, the nitrogen increasing is difficult, and the nitrogen content is difficult to accurately control. The contents of O and S in the molten steel are too high, which is not beneficial to increasing nitrogen in the molten steel and reducing the nitrogen alloying rate, so that the molten steel must be subjected to deep deoxidation and desulfurization before the nitrogen is increased in vacuum. C acts as a strong deoxidizing element in vacuum, and deoxidized products are removed in gaseous form, being the most "clean" deoxidizer under vacuum conditions.
When low-nitrogen stainless steel is smelted in vacuum, the nitrogen increasing amount of molten steel is difficult to accurately control under the condition of nitrogen atmosphere, and the deviation is larger.
Disclosure of Invention
The invention aims to provide a method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by a vacuum induction furnace.
In order to solve the technical problems, the invention adopts the following technical scheme: the method comprises the processes of charging, vacuum heating, refining deoxidization, alloying and nitrogen control tapping;
the charging process comprises the following steps: calculating carbon distribution amount according to the C content requirement in steel, and spreading carbon powder at the bottom of a crucible during charging;
the refining deoxidizing process comprises the following steps: adding rare earth after refining is finished to carry out deep deoxidation and desulfurization;
the alloying process comprises the following steps: during alloying, argon is filled into the furnace;
the nitrogen control tapping process comprises the following steps: adding manganese nitride alloy in the nitrogen-controlling tapping process, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of molten steel, calculating the yield of the manganese nitride alloy according to the following formula (I),
in formula (I): f is alloy yield,%; p (P) L The nitriding pressure is P which is less than or equal to 0.05Mpa L ≤0.075Mpa；P K Is at normal pressure and MPa; n (N) m Saturated solubility of molten steel under non-vacuum condition,%; n (N) i Nitrogen content is increased for molten steel,%.
In the vacuum heating process, the melting time is controlled within 3 hours.
In the refining deoxidation process, the addition amount of rare earth is controlled to be 0.006-0.01 wt%.
The height of the molten steel surface in the crucible and the inner diameter ratio of the crucible satisfy 0.6-h Molten steel /d Crucible pot ≤0.9。
The nitrogen content of the smelting steel grade is 60-300 ppm.
The beneficial effects of adopting above-mentioned technical scheme to produce lie in: the invention not only ensures the stability of the components of the low-nitrogen stainless steel product, but also can accurately control the nitrogen content in the steel, and fully plays the characteristics of the vacuum induction furnace; the carbon deoxidation process and the rare earth deoxidation and desulfurization process after refining are adopted, so that the oxygen and sulfur contents in the steel are maintained at a lower level to the greatest extent, and the nitrogen increasing process of the molten steel is facilitated. The invention is obtained through long-time experience groping, test result analysis and creative labor, the adding amount of the manganese nitride alloy can be accurately calculated according to the nitrogen increasing amount of molten steel, the end-point nitrogen content of the low-nitrogen stainless steel product can be accurately controlled by a formed empirical formula, and the deviation is controlled within 5% of the target nitrogen content.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
The method for smelting low-nitrogen stainless steel by using the vacuum induction furnace is suitable for smelting steel with the nitrogen content of 60-300 ppm, and sequentially comprises the processes of charging, vacuum heating, refining deoxidation, alloying and nitrogen control tapping; the process steps are as follows:
(1) Charging: a vacuum induction furnace with the weight of 50kg to 1.5T is adopted; calculating carbon distribution amount according to the C content requirement in steel, spreading carbon powder at the bottom of a crucible during charging, so as to fully utilize the carbon deoxidization capability under the vacuum condition; then, loading the non-oxidizable volatile alloy such as pure iron, metallic chromium and the like into a crucible of a vacuum induction furnace, and loading the oxidizable volatile alloy such as industrial silicon, aluminum, titanium sponge and electrolytic manganese and the like into a material distributing bin;
(2) Vacuum heating: the melting speed is controlled in the melting period, and the melting time is controlled to be 3 hours or less, so that the molten steel is prevented from overturning and bridging while the deoxidizing time is ensured; after melting, the ratio of the height of the molten steel surface in the crucible to the inner diameter (diameter) of the crucible is more than or equal to 0.6 and less than or equal to h Molten steel /d Crucible pot ≤0.9；
(3) Refining and deoxidizing: after the molten steel is completely melted, maintaining the refining temperature of the molten steel for a certain time, and then finishing refining, adding rare earth for further deoxidizing and desulfurizing, wherein the addition amount of the rare earth is controlled to be 0.006-0.01 wt% of the molten steel;
(4) Alloying: after rare earth is added, the temperature is lowered by power failure, argon with certain pressure is filled into the furnace, and the pressure of the argon is controlled to be 0.05-0.075 Mpa; after the molten steel is formed into a film, adding aluminum particles, electrolytic manganese, sponge titanium and other volatile alloys into the molten steel;
(5) Nitrogen control tapping: raising the temperature of the molten steel to at least 80 ℃ above the liquidus line, preferably 80-90 ℃, adding manganese nitride alloy, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of the molten steel, calculating the yield of the manganese nitride alloy according to the following formula (I),
in formula (I): f is alloy yield,%; p (P) L The nitriding pressure is P which is less than or equal to 0.05Mpa L ≤0.075Mpa；P K Is at normal pressure and MPa; n (N) m Saturated solubility of molten steel under non-vacuum condition,%; n (N) i Nitrogen increasing amount of molten steel,%;
the saturated solubility N of molten steel under the non-vacuum condition m Calculated according to the following formula (II),
in formula (II): [ N ]]Solubility of nitrogen in steel,%; PN (Positive-negative) network 2 Is the partial pressure of nitrogen, atm; t is the temperature of molten steel, K; [ j ]]Is the content of alloy elements in molten steel,%.
After the nitriding alloy is completely melted and no bubble exists on the surface of the molten steel, controlling the temperature of the molten steel to 40-60 ℃ on a liquidus line, and tapping at a constant speed in an electrified way.
Examples 1-3: the method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by using the vacuum induction furnace is specifically as follows.
The equipment adopts a 500kg vacuum induction furnace, the component range requirements of the smelting test steel type 1 are shown in table 2, and the smelting weight is 500kg, h Molten steel /d Crucible pot ＝0.9。
(1) Charging: calculating the carbon distribution amount according to the C content requirement in steel, spreading carbon powder at the bottom of a crucible during charging, and then charging pure iron, metallic chromium, ferromolybdenum and nickel plates into the crucible of a vacuum induction furnace, and charging industrial silicon and electrolytic manganese into a material distributing bin;
(2) Vacuum heating: the melting speed is controlled in the melting period, and the melting time of the examples 1-3 is respectively controlled to be 2h42min, 2h28min and 3h;
(3) Refining and deoxidizing: after the molten steel is completely melted, maintaining the refining temperature of the molten steel for a certain time, adding rare earth for further deoxidization and desulfurization; examples 1-3 rare earth additions are shown in Table 1;
(4) Alloying: after rare earth is added, the temperature is lowered by power failure, and argon is filled into the furnace; examples 1-3 argon charges are shown in table 1; after the molten steel is formed into a film, adding aluminum particles, electrolytic manganese, sponge titanium and other volatile alloys into the molten steel;
(5) Nitrogen control tapping: raising the temperature of molten steel, respectively raising the temperature of the molten steel to 80 ℃, 85 ℃ and 90 ℃ on a liquid phase line in examples 1-3, adding manganese nitride alloy, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of the molten steel, calculating the yield of the manganese nitride alloy according to the formula (I) in examples 1-3, calculating the saturated solubility of the molten steel under non-vacuum condition according to the formula (II), and after the nitrogen alloy is completely melted, controlling the temperature of the molten steel to 40-60 ℃ on the liquid phase line after no bubbles exist on the surface of the molten steel, and tapping at a constant speed in an electrified mode. The smelting endpoint ingredients for examples 1-3 are shown in Table 2.
Taking example 1 as an example, the saturated solubility of molten steel under non-vacuum conditions can be calculated according to the formula (II) based on the composition of molten steel:
solving to obtain [ N ] = 0.2446%;
obtained according to formula (I):
table 1: examples 1 to 3 rare earth addition amount, tapping superheat degree, manganese nitride yield control
| Examples | Rare earth addition/% | Steel tapping superheat degree/DEGC | Inflation pressure/MPa | Manganese nitride yield/% |
| 1 | 0.006 | 40 | 0.05 | 39.3 |
| 2 | 0.008 | 50 | 0.065 | 54.0 |
| 3 | 0.01 | 60 | 0.075 | 63.9 |
Table 2:1-3 examples test Steel 1 composition Range and smelting end point composition (wt%)
In table 2, the balance of the components was Fe and unavoidable impurities.
Examples 4-6: the method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by using the vacuum induction furnace is specifically as follows.
The equipment adopts a 50kg vacuum induction furnace, the component range requirements of the smelting test steel type 2 are shown in Table 4, and the smelting weight is 45kg, h Molten steel /d Crucible pot ＝0.6。
(1) Charging: calculating carbon distribution amount according to the C content requirement in steel, spreading carbon powder at the bottom of a crucible during charging, then charging pure iron and metallic chromium into the crucible of a vacuum induction furnace, and charging industrial silicon and electrolytic manganese into a material distributing bin;
(2) Vacuum heating: the melting speed is controlled in the melting period, and the melting time of the examples 4-6 is respectively controlled to be 2h35min, 3h and 2h50min;
(3) Refining and deoxidizing: after the molten steel is completely melted, maintaining the refining temperature of the molten steel for a certain time, adding rare earth for further deoxidization and desulfurization; examples 4-6 rare earth additions are shown in Table 3;
(4) Alloying: after rare earth is added, the temperature is lowered by power failure, and argon is filled into the furnace; examples 4-6 argon charges are shown in table 3; after the molten steel is formed into a film, adding aluminum particles, electrolytic manganese, sponge titanium and other volatile alloys into the molten steel;
(5) Nitrogen control tapping: raising the temperature of molten steel, respectively raising the temperature of the molten steel to 80 ℃, 85 ℃ and 90 ℃ on a liquid phase line in examples 4-6, adding manganese nitride alloy, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of the molten steel, calculating the yield of the manganese nitride alloy according to the formula (I) in examples 4-6, calculating the saturated solubility of the molten steel under non-vacuum condition according to the formula (II), and after the nitrogen alloy is completely melted, controlling the temperature of the molten steel to 40-60 ℃ on the liquid phase line after no bubbles exist on the surface of the molten steel, and tapping at a constant speed in an electrified mode. The smelting endpoint ingredients for examples 4-6 are shown in Table 4.
Taking example 4 as an example, the saturated solubility of molten steel under non-vacuum conditions can be calculated according to formula (II) from the molten steel composition:
solving to obtain [ N ] =0.0310%;
obtained according to formula (I):
table 3: examples 4 to 6 rare earth addition amount, tapping superheat degree, manganese nitride yield and addition amount control
| Examples | Rare earth addition/% | Steel tapping superheat degree/DEGC | Inflation pressure/MPa | Yield of manganese nitride/％ |
| 4 | 0.006 | 40 | 0.05 | 37.5 |
| 5 | 0.008 | 50 | 0.065 | 51.5 |
| 6 | 0.01 | 60 | 0.075 | 60.9 |
Table 4:4-6 example test Steel 2 composition Range and smelting endpoint composition (wt%)
In table 4, the balance of the components was Fe and unavoidable impurities.
Examples 7 to 9: the method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by using the vacuum induction furnace is specifically as follows.
The equipment adopts a 1.5T vacuum induction furnace, the composition range requirements of the smelting test steel grade 3 are shown in Table 6, and the smelting weight is 1.5T and h Molten steel /d Crucible pot ＝0.8。
(1) Charging: calculating carbon distribution amount according to the C content requirement in steel, spreading carbon powder kg at the bottom of a crucible during charging, and then charging pure iron kg and metal chromium kg into the crucible of a vacuum induction furnace, and charging industrial silicon kg, aluminum kg, titanium sponge kg and electrolytic manganese kg into a material distributing bin;
(2) Vacuum heating: the melting speed is controlled in the melting period, and the melting time of examples 7-9 is respectively controlled to be 2h32min, 2h48min and 3h;
(3) Refining and deoxidizing: after the molten steel is completely melted, maintaining the refining temperature of the molten steel for a certain time, adding rare earth for further deoxidization and desulfurization; examples 7-9 rare earth additions are shown in Table 5;
(4) Alloying: after rare earth is added, the temperature is lowered by power failure, and argon is filled into the furnace; examples 7-9 argon charges are shown in table 5; after the molten steel is formed into a film, adding aluminum particles, electrolytic manganese, sponge titanium and other volatile alloys into the molten steel;
(5) Nitrogen control tapping: raising the temperature of molten steel, respectively raising the temperature of examples 7-9 to 90 ℃, 85 ℃ and 80 ℃ on a liquid phase line, adding manganese nitride alloy, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of the molten steel, calculating the yield of the manganese nitride alloy according to the formula (I) in examples 7-9, calculating the saturated solubility of the molten steel under non-vacuum condition according to the formula (II), and after the nitrogen alloy is completely melted, controlling the temperature of the molten steel to 40-60 ℃ on the liquid phase line after no bubbles exist on the surface of the molten steel, and tapping at a constant speed in an electrified mode. The smelting endpoint ingredients for examples 7-9 are shown in Table 6.
Taking example 7 as an example, the saturated solubility of molten steel under non-vacuum conditions can be calculated according to formula (II) from the molten steel composition:
solving to obtain [ N ] = 0.0382%;
obtained according to formula (I):
table 5: examples 7 to 9 control of rare earth addition amount, tapping superheat degree, manganese nitride yield and addition amount
| Examples | Rare earth addition/% | Steel tapping superheat degree/DEGC | Inflation pressure/MPa | Manganese nitride yield/% |
| 7 | 0.006 | 40 | 0.05 | 18.3 |
| 8 | 0.008 | 50 | 0.065 | 25.1 |
| 9 | 0.01 | 60 | 0.075 | 29.7 |
Table 6:7-9 example test Steel 3 composition Range and smelting endpoint composition (wt%)
In table 6, the balance of the components was Fe and unavoidable impurities.
Claims (1)
1. A method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by a vacuum induction furnace is characterized by comprising the following steps of: the method comprises the processes of charging, vacuum heating, refining deoxidization, alloying and nitrogen control tapping;
the charging process comprises the following steps: calculating carbon distribution amount according to the C content requirement in steel, and spreading carbon powder at the bottom of a crucible during charging;
the refining deoxidizing process comprises the following steps: adding rare earth for deep deoxidation and desulfurization after refining, wherein the addition amount of the rare earth is controlled to be 0.006-0.01 wt%;
the alloying process comprises the following steps: during alloying, argon is filled into the furnace;
the nitrogen control tapping process comprises the following steps: adding manganese nitride alloy in the nitrogen-controlling tapping process, calculating the adding amount of the manganese nitride alloy according to the nitrogen increasing amount of molten steel, calculating the yield of the manganese nitride alloy according to the following formula (I),
in formula (I): f is alloy yield,%; p (P) L The nitriding pressure is P which is less than or equal to 0.05Mpa L ≤0.075Mpa；P K Is at normal pressure and MPa; n (N) m Saturated solubility of molten steel under non-vacuum condition,%; n (N) i Nitrogen increasing amount of molten steel,%;
the vacuum heating process is carried out, and the melting time is controlled within 3 hours; the ratio of the height of the molten steel surface in the crucible to the inner diameter of the crucible is more than or equal to 0.6 and less than or equal to h Molten steel /d Crucible pot ≤0.9；
The nitrogen content of the smelting steel is 60-300 ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202211210503.2A CN115572790B (en) | 2022-09-30 | 2022-09-30 | Method for precisely controlling nitrogen in smelting low-nitrogen stainless steel by vacuum induction furnace |
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| CN101372721A (en) * | 2008-09-19 | 2009-02-25 | 山西太钢不锈钢股份有限公司 | High vacuum induction furnace nitrogen-containing steel smelting nitrogen pickup method |
| CN103741006A (en) * | 2014-01-09 | 2014-04-23 | 张家港浦项不锈钢有限公司 | Preparation method of Ti-containing low-nitrogen stainless steel |
| JP2015030868A (en) * | 2013-08-01 | 2015-02-16 | Ｊｆｅスチール株式会社 | Method for refining extra-low nitrogen pure iron |
| CN105970074A (en) * | 2016-05-30 | 2016-09-28 | 河北钢铁股份有限公司 | Method for quickly smelting low-nitrogen stainless steel through vacuum induction furnace |
| CN111334702A (en) * | 2020-03-20 | 2020-06-26 | 浙江天马轴承集团有限公司 | Preparation method of high-strength high-nitrogen rare earth stainless bearing steel |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101372721A (en) * | 2008-09-19 | 2009-02-25 | 山西太钢不锈钢股份有限公司 | High vacuum induction furnace nitrogen-containing steel smelting nitrogen pickup method |
| JP2015030868A (en) * | 2013-08-01 | 2015-02-16 | Ｊｆｅスチール株式会社 | Method for refining extra-low nitrogen pure iron |
| CN103741006A (en) * | 2014-01-09 | 2014-04-23 | 张家港浦项不锈钢有限公司 | Preparation method of Ti-containing low-nitrogen stainless steel |
| CN105970074A (en) * | 2016-05-30 | 2016-09-28 | 河北钢铁股份有限公司 | Method for quickly smelting low-nitrogen stainless steel through vacuum induction furnace |
| CN111334702A (en) * | 2020-03-20 | 2020-06-26 | 浙江天马轴承集团有限公司 | Preparation method of high-strength high-nitrogen rare earth stainless bearing steel |
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