CN115369212A - Smelting method of ultra-low phosphorus steel - Google Patents
Smelting method of ultra-low phosphorus steel Download PDFInfo
- Publication number
- CN115369212A CN115369212A CN202210943026.4A CN202210943026A CN115369212A CN 115369212 A CN115369212 A CN 115369212A CN 202210943026 A CN202210943026 A CN 202210943026A CN 115369212 A CN115369212 A CN 115369212A
- Authority
- CN
- China
- Prior art keywords
- slag
- steel
- dephosphorization
- blowing
- converter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 144
- 239000010959 steel Substances 0.000 title claims abstract description 144
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 49
- 239000011574 phosphorus Substances 0.000 title claims abstract description 49
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 45
- 238000003723 Smelting Methods 0.000 title claims abstract description 38
- 239000002893 slag Substances 0.000 claims abstract description 167
- 238000007664 blowing Methods 0.000 claims abstract description 96
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000001301 oxygen Substances 0.000 claims abstract description 52
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 52
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 47
- 238000005261 decarburization Methods 0.000 claims abstract description 28
- 239000000463 material Substances 0.000 claims abstract description 25
- 238000010079 rubber tapping Methods 0.000 claims abstract description 23
- 229910052742 iron Inorganic materials 0.000 claims abstract description 17
- 239000013049 sediment Substances 0.000 claims abstract description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 26
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 26
- 239000004571 lime Substances 0.000 claims description 26
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 13
- 239000011777 magnesium Substances 0.000 claims description 13
- 229910052749 magnesium Inorganic materials 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 10
- 229910000514 dolomite Inorganic materials 0.000 claims description 8
- 239000010459 dolomite Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 238000005262 decarbonization Methods 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 17
- 239000000395 magnesium oxide Substances 0.000 description 15
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 15
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 12
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 229910052786 argon Inorganic materials 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 239000002994 raw material Substances 0.000 description 5
- 239000000956 alloy Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910001720 Åkermanite Inorganic materials 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
- 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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
-
- 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
- C21C7/076—Use of slags or fluxes as treating agents
-
- 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
Abstract
The application provides a smelting method of ultra-low phosphorus steel, which comprises the following steps: s10: adding slag splashing materials into the converter after the steel tapping of the previous furnace is finished, then deslagging, and adding scrap steel and molten iron; s20: adding a first batch of slag charge into the converter after charging, carrying out bottom blowing and top blowing dephosphorization, and pouring all dephosphorization slag after dephosphorization blowing is finished; s30: and adding a second batch of slag charge into the converter after dephosphorization, carrying out bottom blowing and top blowing decarburization, tapping after decarburization blowing is finished to obtain ultra-low phosphorus steel, and reserving final slag in the converter. This application is through improving on the basis of two slag method smelting technology, stays and gets last stove final slag, can improve the slag basicity, improves dephosphorization efficiency, and in the dephosphorization stage, optimize rifle position and oxygen suppliment intensity, improve slagging efficiency, and then improve once and fall the sediment dephosphorization rate, cooperate follow-up decarbonization converting, can reduce in the steel phosphorus content and obtain the ultralow phosphorus steel.
Description
Technical Field
The application relates to the field of ferrous metallurgy, in particular to a smelting method of ultra-low phosphorus steel.
Background
On one hand, the higher phosphorus content in the steel can obviously reduce the low-temperature impact toughness of the steel, improve the ductile-brittle transition temperature of the steel, cause the steel to be cold-brittle and deteriorate the welding performance; on the other hand, with the continuous promotion of the quality benefit strategy of enterprise varieties, the produced steel grades gradually turn to the field of high-variety and high-added-value steel, and the phosphorus content of high-end variety steel in the steel is extremely strict, and particularly, the phosphorus content of low-temperature steel, marine steel, container steel, hydrogen-induced crack resistant steel and the like is required to be less than 0.010 percent or 0.005 percent. Based on the influence of phosphorus on the performance of steel products, the phosphorus content in the steel products must be strictly controlled in order to meet the performance requirements of the products in the aspects of traffic, ocean engineering and energy.
Therefore, how to better reduce the phosphorus content in the steel becomes one of the key problems to be solved urgently in the smelting production of the converter.
Disclosure of Invention
The application provides a smelting method of ultra-low phosphorus steel, which is characterized in that the smelting method is improved on the basis of a double-slag smelting process, and conditions in a dephosphorization blowing stage are controlled, so that the ultra-low phosphorus steel is obtained.
In a first aspect, the application provides a smelting method of ultra-low phosphorus steel, comprising the following steps:
s10: adding slag splashing materials into the converter after the steel tapping of the previous furnace is finished, then deslagging, and adding scrap steel and molten iron;
s20: add first batch slag charge in the converter that finishes to feeding, carry out the bottom blowing dephosphorization of top-blown, pour whole dephosphorization sediment after the dephosphorization converting, wherein the top-blown condition specifically is:
after the top blowing is started, the lance is kept at 1.3-1.7 m for 0.5-1 min for oxygen blowing, and the oxygen supply intensity is 230-250 m 3 /h·t；
Then keeping the lance position at 1.0-1.3 m for 1-2 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
Finally, keeping the lance position at 1.3-1.5 m for 1.5-3 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
S30: and adding a second batch of slag charge into the converter after dephosphorization, carrying out bottom blowing and top blowing decarburization, tapping after decarburization blowing is finished to obtain ultra-low phosphorus steel, and reserving final slag in the converter.
In the technical scheme of this application, through improving on the basis of two slag method smelting process, leave and get last stove final slag, can improve the slag basicity, improve the dephosphorization efficiency, in the dephosphorization stage, improve the gun position earlier stage, follow-up reduction gun position, make the first slag charge of interpolation melt fast, form the active slag of high basicity as early as possible, promote the gun position again at last, and improve oxygen suppliment intensity, be favorable to improving converter stirring strength, improve slagging efficiency, and then improve one-time deslagging dephosphorization rate, cooperate follow-up decarburization blowing, can reduce in the steel phosphorus content and obtain the ultralow phosphorus steel.
In some embodiments of the present application, in the step S10, the slag splashed material is 1.8 to 2.3kg of magnesium balls per ton of steel and 3.5 to 5.0kg of lime per ton of steel.
In some embodiments of the application, in the step S10, the deslagging specifically includes: 1/3-1/2 of the total slag amount is left when the slag is poured.
In some embodiments of the present application, in the step S10, the adding scrap steel and molten iron specifically includes: firstly adding part of the scrap steel, then adding molten iron, and finally adding the rest scrap steel, wherein the scrap steel ratio in the converter is 25-36 percent finally.
In some embodiments of the present application, in the step S20, the first batch of slag is one or more of 9 to 16kg lime per ton of steel, 2 to 3kg magnesium balls per ton of steel, 1.5 to 2.5kg slag formers per ton of steel, or 2.5 to 4kg raw dolomite per ton of steel.
In some embodiments of the present application, in the step S20, caO/SiO in the dephosphorization residues 2 The binary alkalinity R is 1.3 to 2.1;
optionally, the mass percent of MgO in the dephosphorized slag is 6-8%;
optionally, the weight percentage of the total Fe in the dephosphorization slag is 12-20%.
In some embodiments of the present application, in the step S30, the second slag material is one or more of 15 to 30kg lime per ton steel, 4 to 6kg magnesium balls per ton steel, 1 to 3.5kg slag melting agent per ton steel, and 2 to 4kg raw dolomite per ton steel.
In some embodiments of the present application, in the steps S20 and S30, the intensity of the bottom-blowing gas is 0.55-0.85 m 3 /h·t。
In some embodiments of the present application, in step S30, the tapping specifically includes:
after 2-3 kg lime is added into a converter per ton steel, the gas supply intensity of bottom blowing is 0.4-0.7 m 3 Tapping under the condition of/h.t.
In some embodiments of the present application, in step S30, caO/SiO in the final slag is 2 The binary alkalinity R is 2.5 to 3.5;
optionally, the mass percent of MgO in the final slag is 7-9%;
optionally, the mass percentage of the total Fe in the final slag is 15-26%.
Detailed Description
The examples or embodiments are described in a progressive arrangement throughout this specification, each with emphasis on illustrating differences from the other examples.
In the description herein, references to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
With the rapid development of national defense, aviation and aerospace, petroleum, automobile, microelectronic and other industries, the demand for ultra-low phosphorus steel is also increasing. The existing main production method for producing the low-phosphorus steel comprises the following steps: 1) Molten iron pretreatment and a single slag method; 2) A converter duplex method; 3) The double slag method. However, the molten iron temperature is easily reduced by the molten iron pretreatment and the single slag method, the whole production balance is influenced by the long smelting production period of the converter duplex method, the quantity of slag smelted by the duplex method is large, and the metal loss is large during smelting in a dephosphorization furnace and a decarburization furnace, so that the production cost is influenced. Therefore, the inventor optimizes the smelting process of the double slag method to obtain the ultra-low phosphorus steel.
The application provides a smelting method of ultra-low phosphorus steel, which comprises the following steps:
s10: adding slag splashing materials into the converter after the steel tapping of the previous furnace is finished, then deslagging, and adding scrap steel and molten iron;
s20: adding the first batch of slag charge into the converter that finishes to feeding, carrying out bottom blowing top blowing dephosphorization, pouring off whole dephosphorization sediment after dephosphorization converting finishes, wherein the top blowing condition specifically is:
after the top blowing is started, the lance is kept at 1.3-1.7 m for 0.5-1 min for oxygen blowing, and the oxygen supply intensity is 230-250 m 3 /h·t；
Then keeping the lance position at 1.0-1.3 m for 1-2 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
Finally, keeping the lance position at 1.3-1.5 m for 1.5-3 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
S30: and adding a second batch of slag charge into the converter after dephosphorization, carrying out bottom blowing and top blowing decarburization, and tapping after decarburization blowing to obtain the ultra-low phosphorus steel.
In the technical scheme of this application, through improving on the basis of two slag method smelting process, reserve and get last stove final slag, can improve the slag basicity, improve dephosphorization efficiency, in the dephosphorization stage, reduce the gun position after improving the gun position earlier stage, make the first slag charge of interpolation melt fast, form the active slag of high basicity as early as possible, promote the gun position again at last, and improve the blowing oxygen volume, be favorable to improving converter stirring strength, improve slagging efficiency, and then improve the once deslagging dephosphorization rate, cooperate follow-up decarburization blowing, can reduce in the steel phosphorus content and obtain the ultralow phosphorus steel.
In the technical scheme of the application, in the step S10, the slag containing high alkalinity and high oxidizability in the last furnace is reserved for the next furnace, so that the early-stage alkalinity of the converter can be increased, the problem of insufficient alkalinity caused by difficulty in lime melting in the early stage is solved, and meanwhile, higher FeO in the slag can promote the melting of newly added lime, the slag melting efficiency of the slag is improved, and the utilization efficiency of iron can be improved; in addition, the residual slag brings a part of slag quantity, promotes the increase of the total slag quantity, and can play a role in diluting phosphorus pentoxide in the slag.
In the technical scheme of the application, the step S20 is mainly used for controlling blowing conditions in a dephosphorization stage, a top-bottom combined blowing method is adopted in the dephosphorization stage, the stirring efficiency in the converter is improved, molten steel and slag materials are fully reacted, the dephosphorization efficiency is improved, meanwhile, the specific position of a gun position and oxygen blowing amount in the blowing process are further optimized, the gun position is firstly raised at the early stage and then the gun position is raised at the bottom, lime in the slag materials can be rapidly melted, the alkalinity of the converter is improved, the dephosphorization efficiency is improved, the area of a reaction area of the converter is increased and the stirring intensity is increased by improving the gun position and improving the oxygen blowing amount, and the dephosphorization rate is improved; with the rise of the smelting temperature, before the severe decarburization reaction comes on a large scale, blowing in the dephosphorization stage is finished, and the dephosphorization slag with high phosphorus pentoxide content is quickly poured out to prevent the phosphorus return phenomenon.
In the technical scheme of the application, step S30 is mainly a decarburization stage, a second batch of slag is added for decarburization treatment, partial dephosphorization is carried out in the decarburization treatment process, the phosphorus content of the tapped steel is further reduced, in addition, the tapped steel is kept in the furnace for the next furnace after decarburization is finished, feO which cannot be recovered in the slag can be recycled in a hot state, and meanwhile, the high-alkalinity decarburization slag containing a large amount of CaO in the final slag can be reused in the dephosphorization stage of the next furnace, so that the use amount of the slag in the steelmaking process can be reduced, the cost is reduced, and the obvious economic benefit is achieved.
In some embodiments of the present application, the slag splashed in step S10 is 1.8 to 2.3kg magnesium balls per ton steel and 3.5 to 5.0kg lime per ton steel.
In some embodiments, the slag splashing material is used for slag splashing treatment of the final slag in the previous furnace, so that on one hand, the heat in the furnace can be further utilized to prevent splashing, and on the other hand, the slag splashing material is melted to further improve the alkalinity in the converter, thereby improving the dephosphorization rate.
In some embodiments of the present application, in step S10, the deslagging specifically includes: 1/3-1/2 of the total slag amount is left when the slag is poured.
In some embodiments, the amount of the remaining slag affects the dephosphorization of the converter, the amount of the remaining slag is too small, the effect of the remaining slag cannot be fully exerted, the amount of the remaining slag is too large, splashing or slag overflow can be caused, the amount of the slag is too large, the heat loss in the converter can be increased, the fluidity of the slag is deteriorated, and therefore 1/3-1/2 of the total amount of the slag is remained during slag dumping, high dephosphorization distribution ratio is facilitated, and a better dephosphorization effect is achieved.
In some embodiments of the present application, in the step S10, adding the scrap steel and the molten iron specifically includes: firstly adding part of the scrap steel, then adding molten iron, and finally adding the rest scrap steel, wherein the scrap steel ratio in the converter is 25-36%.
In some embodiments, the final steel scrap ratio in the converter is 25% -36%, and the steel scrap ratio in a common smelting method is 10-12%, because the heat of a converter molten pool is low due to the continuous increase of the steel scrap ratio, the early-stage slagging is difficult, the fluidity of the slag is poor, the dephosphorization reaction is carried out all the time, and the dephosphorization is adversely affected; in the embodiment, the smelting method provided by the application can be used for increasing the scrap steel ratio to 25% -36%, still has a good dephosphorization effect, and the addition of a certain amount of scrap steel can improve the steel material, reduce the consumption of raw materials and well achieve the purpose of reducing the smelting cost.
The inventor notices that the main reason influencing the dephosphorization effect of the high scrap ratio is that a large amount of heat required by melting the scrap iron can reduce the temperature of the converter, so that the early-stage slagging is difficult, in the technical scheme of the application, the heat of the final slag of the last furnace is kept, the slag splashing of slag splashing materials is added, part of the scrap steel is added after slag dumping, and further the heat of the final slag is utilized to melt part of the scrap steel, and the part of the scrap steel also serves as a coolant to balance the temperature of the converter, so that the blowing is stably carried out, the splashing is prevented, molten iron and the rest of the scrap steel are added subsequently, and meanwhile, because the final slag has higher alkalinity, the quality of the first batch of slag added in the dephosphorization stage is lower, the required melting heat is lower, and the normal slagging can be ensured under the condition of the high scrap ratio by matching with a specific gun position and the oxygen blowing amount, so that the fluidity of the slag is ensured, and a good dephosphorization effect is achieved.
In some embodiments of the present application, in step S20, the first batch of slag is one or more of 9 to 16kg lime per ton of steel, 2 to 3kg magnesium balls per ton of steel, 1.5 to 2.5kg slag formers per ton of steel, or 2.5 to 4kg raw dolomite per ton of steel.
In some embodiments, the first slag material is one or more of lime, magnesium balls, slagging agents and raw dolomite, which are all slag materials commonly used in the field and can be selected according to raw materials; in the embodiment, the addition amount of the slag is limited and is obviously lower than that of the first batch of slag in the common double-slag method, so that the cost is saved, and the good dephosphorization effect can be still ensured. Because the final slag of the previous furnace contains higher content of CaO and has higher alkalinity, the first batch of slag can achieve good dephosphorization effect without adding too much slag, and in addition, the lower addition amount also ensures that the slagging does not need too much heat, thereby ensuring the heat of a molten pool in the converter and ensuring that the raw material with high scrap ratio can still achieve good dephosphorization effect.
In some embodiments of the present application, in step S20, caO/SiO in the dephosphorization residues 2 The binary alkalinity R is 1.3 to 2.1;
optionally, the mass percent of MgO in the dephosphorized slag is 6-8%;
optionally, the weight percentage of the total Fe in the dephosphorization slag is 12-20%.
In some embodiments, caO/SiO in the dephosphorization residues 2 The binary alkalinity R is within the range of 1.3-2.1, the phosphorus content of the molten steel is reduced along with the increase of the alkalinity, and the dephosphorization rate is increased because the alkalinity is increased, namely the quantity of liquid slag in the furnace is increased, the viscosity of the slag is reduced, the fluidity of the slag is improved, and the mass transfer coefficient of phosphorus pentoxide in the slag is increased, so that the dephosphorization rate is increased; therefore, caO/SiO in the dephosphorized slag 2 The binary basicity R is within the range of 1.3-2.1, and the higher dephosphorization rate of the molten steel in the converter can be ensured.
Furthermore, the mass percent of MgO in the dephosphorized slag is 6-8%, and the dissolution of lime can be promoted by increasing the MgO content in the slag, so that the formation of high-melting-point compact 2 CaO. SiO on the surface of the lime is delayed 2 And a shell layer forms mineral phases with low melting points such as akermanite and the like, so that slagging is facilitated, a proper amount of MgO is beneficial to reducing the viscosity of the slag, excessive MgO can reduce the viscosity and is not beneficial to dephosphorization, and therefore, the mass percentage of MgO in the dephosphorization slag is in a range of 6-8%, and dephosphorization is facilitated.
Furthermore, the mass percent of the total Fe in the dephosphorization slag is within the range of 12-20%, the total Fe in the dephosphorization slag mainly exists in the form of FeO, the FeO content in the dephosphorization slag is increased, namely, the oxidability of the slag is increased, the dissolution of lime can be accelerated, the fluidity of the slag is improved, and good conditions are provided for dephosphorization reaction.
In some embodiments of the present application, in step S30, the second batch of slag is one or more of 15 to 30kg lime per ton steel, 4 to 6kg magnesium balls per ton steel, 1 to 3.5kg slag melting agent per ton steel, and 2 to 4kg raw dolomite per ton steel.
In some of the above embodiments, the kind of the second slag material is not different from that of the first slag material, and the main difference is the addition amount, because the dephosphorizing slag contains higher phosphorus pentoxide, so that in order to avoid the phenomenon of phosphorus return with the rise of temperature, the whole dephosphorizing slag is poured out after the end of the dephosphorizing stage, and the slag material is added again in the subsequent decarbonizing blowing stage, so that the addition amount is higher than that of the first slag material, although most of phosphorus is removed in the dephosphorizing stage, in the decarbonizing stage, the phosphorus content in the molten steel is still further reduced along with the dephosphorizing reaction.
In some embodiments of the present application, the top-blowing conditions in step 30 are specifically:
after the top blowing is started, keeping the lance position at 1.4-1.7 m for 0.5-1.5 min to blow oxygen, wherein the oxygen blowing amount is 260-290 m 3 /h·t；
Then keeping the lance position at 0.9-1.1 m for 2-3 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
Then keeping the lance position at 1.2-1.5 m for 1-2 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
Finally, keeping the lance position at 0.8-1.0 m for 1-2 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t。
In the above embodiment, a good decarburization and dephosphorization effect is ensured by controlling the top blowing condition in the decarburization stage, the lower carbon content in the molten steel is beneficial to improving the dephosphorization efficiency, and because the carbon content in the molten steel at the end point of the converter smelting obviously affects the oxygen potential of the molten steel and the slag, and the higher equilibrium oxygen potential is required to meet the condition of oxidative dephosphorization when the phosphorus content in the molten steel is reduced to the lower content.
In some embodiments of the present application, in steps S20 and S30, the intensity of the bottom blowing air is 0.55-0.85 m 3 /h·t。
In the above embodiment, in steps S20 and S30, the intensity of bottom-blown air is controlled to be 0.55 to 0.85m 3 The method is characterized in that the method adopts bottom blowing and top blowing combined blowing to carry out smelting, the type of bottom blowing is not further limited, any inert gas such as nitrogen or argon can be selected, and the method mainly has the main effects of improving the stirring speed in the converter by matching with top blowing, thereby improving the mass transfer efficiency and ensuring more complete dephosphorization and decarburization.
In some embodiments of the present application, the temperature of the molten steel at the end of the decarburization blowing at step S30 is 1550 to 1650 ℃.
In some embodiments of the present application, in step S30, the tapping specifically includes:
after 2-3 kg lime/ton steel is added into the converter, the air supply intensity by bottom blowing is 0.4-0.7 m 3 Tapping under the condition of/h.t.
In some embodiments, the temperature of the molten steel is higher when decarburization blowing is finished, so lime needs to be added for tapping, the higher the tapping temperature is, the higher the oxygen potential required for achieving the same dephosphorization effect is, and the higher the difficulty of corresponding dephosphorization conditions is, so in order to reduce the phosphorus content in the molten steel, the lime is added for improving the alkalinity of the final slag, so that the balanced oxygen activity required for dephosphorization is reduced, the influence of temperature on dephosphorization is counteracted, meanwhile, the addition of the lime can also reduce the temperature of the molten steel, and in addition, the improvement of the alkalinity of the final slag can be used for smelting in the next furnace, so that the smelting of the next furnace for ultralow phosphorus steel is facilitated.
In the first of this applicationIn some examples, in step S30, caO/SiO in the final slag is 2 The binary alkalinity R is 2.5-3.5;
optionally, the mass percent of MgO in the final slag is 7-9%;
optionally, the mass percent of the total Fe in the final slag is 15-26%.
In some of the above examples, the final slag contains CaO/SiO 2 The binary basicity R is in the range of 2.5-3.5, if the basicity is too low, dephosphorization is not facilitated, if the basicity is too high, the carbon content of the molten steel at the end point is high, so that the slag becomes viscous, the fluidity is poor, and dephosphorization is not facilitated, therefore, the fluidity of the slag is ensured, and meanwhile, the basicity is properly improved, and the dephosphorization of the converter is facilitated.
Furthermore, the mass percentage of MgO in the final slag is in the range of 7-9%, because the excessive MgO content can cause a large amount of undissolved magnesium oxide solid particles in the slag, the viscosity and the melting temperature of the slag are influenced, the excessively sticky slag can slow down the reaction between the slag and metal, the dephosphorization effect is influenced, meanwhile, the effect of the magnesium oxide in the dephosphorization and phosphorus fixation processes is far inferior to that of CaO and FeO which directly participate in the reaction, the increase of the magnesium oxide content can dilute the effect of the CaO and FeO, the dephosphorization effect is deteriorated, and therefore, the mass percentage of the MgO in the final slag is controlled in the range of 7-9%.
Furthermore, the mass percent of the total Fe in the final slag is within the range of 15-26%, because the total Fe in the final slag mainly exists in the form of FeO, and the higher the content of FeO in the final slag is, the higher the corresponding equilibrium oxygen activity is, in order to obtain the ultra-low phosphorus steel, the higher the content of the total Fe in the final slag needs to be ensured, but the waste of Fe element can be found out if the content is too high, so the mass percent of the total Fe in the final slag is controlled within the range of 15-26%.
In some embodiments of the present application, in step S30, when the tapped amount is 1/3 to 1/2 of the total steel amount, the alloy is added to the converter.
In the above examples, the alloy was added to obtain ultra-low phosphorous steel having other special properties when tapping was 1/3 to 1/2 of the total amount of steel.
The method for producing an ultralow phosphorus steel according to the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples at all.
Example 1
Smelting 30CrMo ultra-low phosphorus steel:
a100 t converter is adopted, slag is remained, after the last tapping is finished, 4.8kg of lime and 2.1kg of magnesium balls are added per ton of steel slag splashing, 1/3 of the total slag amount is remained during slag pouring, the converter body is shaken to a charging angle, 5 tons of scattered steel scrap is added, 70.2 tons of molten iron are added, and 28.6 tons of steel scrap are added.
The strength of the bottom blowing argon supply of the converter is set to be 60m before the oxygen lance is blown 3 And h, carrying out bottom blowing stirring in the whole process of dephosphorization decarburization blowing.
Adding 14.4kg lime/ton steel, 2.1kg magnesium ball/ton steel and 3.1kg raw dolomite/ton steel into a converter after charging, keeping the intensity of bottom blowing argon unchanged, and after top blowing, keeping the lance position at 1.5m for 0.5min for blowing oxygen with the oxygen supply intensity of 24000m 3 H; then keeping the lance position at 1.2m for 1.5min for oxygen blowing with oxygen supply intensity of 27500m 3 H; finally keeping the lance position at 1.5m for 2.5min for oxygen blowing with oxygen supply intensity of 27500m 3 H; pouring all dephosphorization residues after dephosphorization blowing is finished;
adding 24.1kg lime/ton steel and 6kg magnesium ball/ton steel into the converter after dephosphorization, keeping the intensity of bottom blowing argon unchanged, and after top blowing, keeping the lance position at 1.55m for 0.5min for blowing oxygen, wherein the oxygen supply intensity is 28500m 3 H; then keeping the lance at 0.95m for 2.5min for oxygen blowing with oxygen supply intensity of 28500m 3 H; then keeping the lance position at 1.25m for 1min for oxygen blowing with oxygen supply intensity of 28500m 3 H; finally keeping the lance position at 0.85m for 1min for oxygen blowing with the oxygen supply intensity of 28500m 3 H; after the decarburization blowing was completed, 2.3kg of lime per ton of steel was added to the converter, and then argon was supplied by bottom blowing at a strength of 45m 3 Tapping under the condition of/h.t, when the tapping is 1/3 of the total steel quantity, adding alloy materials required by 30CrMo steel into the converter, obtaining 30CrMo ultra-low phosphorus steel after tapping, and reserving final slag in the converter.
Example 2
This example differs from example 1 in that: the addition amount and parameters of the materials in each step are different, and the specific addition amount and parameters refer to tables 1-4.
Example 3
The present example differs from example 1 in that: the addition amount and parameters of the materials in each step are different, and the specific addition amount and parameters refer to tables 1-4.
Example 4
This example differs from example 1 in that: the addition amount and parameters of the materials in each step are different, and the specific addition amount and parameters refer to tables 1-4.
TABLE 1 slag splash and Primary feed parameters
TABLE 2 dephosphorization blowing parameters
TABLE 3 decarburization blowing parameters
TABLE 4 bottom blowing argon supply strength parameters and tapping slag-regulating parameters
In examples 1 to 4, the composition of the final slag, the composition of the molten steel at the end of decarburization blowing, and the composition of the obtained 30CrMo ultra low phosphorus steel were measured, and the results are shown in tables 5 to 7.
From the results in Table 5, it is understood that CaO/SiO in the final slag 2 The binary alkalinity R is high, dephosphorization is facilitated, simultaneously, the CaO content in the final slag is high, the final slag is left in a converter to be used as the next furnace for smelting, the use amount of slag charge can be saved, and the problem of insufficient alkalinity of a converter molten pool can be avoided.
From the results in tables 6 and 7, it can be seen that the phosphorus content of molten steel at the decarburization blowing end point is lower than 0.0045%, and meanwhile, the phosphorus content of 30CrMo ultra-low phosphorus steel obtained after alloy addition during tapping is also lower than 0.0055%, which meets the relevant standard of ultra-low phosphorus steel, and indicates that the smelting method provided by the application has good dephosphorization efficiency, can significantly reduce the phosphorus content in steel, and in addition, the scrap steel ratio of the raw materials used in examples 1 to 4 exceeds 30%, which indicates that the smelting method provided by the application can improve the proportion of scrap steel in the raw materials, thereby achieving the purposes of saving resources, reducing waste and reducing production cost.
TABLE 5 Final slag composition and CaO/SiO 2 Binary basicity R
TABLE 6 molten steel composition and temperature at the end of decarburization blowing
| Examples | C，％ | Si，％ | Mn，％ | P，％ | S，％ | Cr，％ | Mo，％ | Temperature, C |
| Example 1 | 0.0586 | 0.0012 | 0.0406 | 0.0042 | 0.0240 | 0.0125 | 0.0029 | 1586 |
| Example 2 | 0.0873 | 0.0024 | 0.0507 | 0.0030 | 0.0201 | 0.0176 | 0.0130 | 1580 |
| Example 3 | 0.0596 | 0.0018 | 0.0439 | 0.0041 | 0.0192 | 0.0108 | 0.0032 | 1564 |
| Example 4 | 0.0522 | 0.0018 | 0.0438 | 0.0041 | 0.0189 | 0.0114 | 0.0035 | 1607 |
TABLE 7 ultra low phosphorus steel composition
| Examples | C，％ | Si，％ | Mn，％ | P，％ | S，％ | Cr，％ | Mo，％ |
| Example 1 | 0.1760 | 0.2896 | 0.4550 | 0.0048 | 0.0241 | 0.5266 | 0.1311 |
| Example 2 | 0.1569 | 0.3516 | 0.3486 | 0.0038 | 0.0367 | 0.4986 | 0.1335 |
| Example 3 | 0.1478 | 0.2110 | 0.3916 | 0.0049 | 0.0187 | 0.4216 | 0.1201 |
| Example 4 | 0.1999 | 0.2047 | 0.5605 | 0.0054 | 0.0214 | 0.7134 | 0.1143 |
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. The smelting method of the ultra-low phosphorus steel is characterized by comprising the following steps:
s10: adding slag splashing materials into the converter after the steel tapping of the previous furnace is finished, then deslagging, and adding scrap steel and molten iron;
s20: add first batch slag charge in the converter that finishes to feeding, carry out the bottom blowing dephosphorization of top-blown, pour whole dephosphorization sediment after the dephosphorization converting, wherein the top-blown condition specifically is:
after the top blowing is started, keeping the lance position at 1.3-1.7 m for 0.5-1 min for oxygen blowing, wherein the oxygen supply intensity is 230-250 m 3 /h·t；
Then keeping the lance position at 1.0-1.3 m for 1-2 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
Finally, keeping the lance position at 1.3-1.5 m for 1.5-3 min for oxygen blowing with the oxygen blowing amount of 260-290 m 3 /h·t；
S30: and adding a second batch of slag charge into the converter after dephosphorization, carrying out bottom blowing and top blowing decarburization, tapping after decarburization blowing is finished to obtain ultra-low phosphorus steel, and reserving final slag in the converter.
2. The smelting method according to claim 1, wherein in the step S10, the slag splashed material is 1.8 to 2.3kg of magnesium balls per ton of steel and 3.5 to 5.0kg of lime per ton of steel.
3. The smelting method according to claim 1 or 2, wherein in the step S10, the deslagging specifically comprises: 1/3-1/2 of the total slag amount is left when the slag is poured.
4. The smelting method according to claim 1, wherein in the step S10, the adding of the scrap steel and the molten iron specifically includes: firstly adding part of the scrap steel, then adding molten iron, and finally adding the rest scrap steel, wherein the scrap steel ratio in the converter is 25-36 percent finally.
5. A smelting process according to claim 3, wherein in step S20, the first slag charge is a mixture of one or more of 9 to 16kg lime per ton steel, 2 to 3kg magnesium balls per ton steel, 1.5 to 2.5kg slag formers per ton steel or 2.5 to 4kg raw dolomite per ton steel.
6. The smelting method according to claim 5, wherein in step S20, caO/SiO in the dephosphorized slag is 2 The binary alkalinity R is 1.3 to 2.1;
optionally, the mass percent of MgO in the dephosphorized slag is 6-8%;
optionally, the weight percentage of the total Fe in the dephosphorization slag is 12-20%.
7. The smelting process according to claim 1, wherein in the step S30, the second batch of slag material is one or more of 15 to 30kg of lime per ton of steel, 4 to 6kg of magnesium balls per ton of steel, 1 to 3.5kg of slag melting agent per ton of steel, and 2 to 4kg of raw dolomite per ton of steel.
8. The smelting method according to claim 1, wherein in the steps S20 and S30, the intensity of bottom-blown gas is 0.55 to 0.85m 3 /h·t。
9. The smelting method according to claim 1, wherein in the step S30, the tapping specifically comprises:
after 2-3 kg lime is added into a converter per ton steel, the gas supply intensity of bottom blowing is 0.4-0.7 m 3 Tapping under the condition of/h.t.
10. The smelting method according to claim 1, wherein in the step S30, caO/SiO in the final slag is 2 The binary alkalinity R is 2.5 to 3.5;
optionally, the mass percent of MgO in the final slag is 7-9%;
optionally, the mass percentage of the total Fe in the final slag is 15-26%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210943026.4A CN115369212B (en) | 2022-08-08 | 2022-08-08 | Smelting method of ultralow-phosphorus steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210943026.4A CN115369212B (en) | 2022-08-08 | 2022-08-08 | Smelting method of ultralow-phosphorus steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115369212A true CN115369212A (en) | 2022-11-22 |
| CN115369212B CN115369212B (en) | 2023-10-27 |
Family
ID=84063005
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210943026.4A Active CN115369212B (en) | 2022-08-08 | 2022-08-08 | Smelting method of ultralow-phosphorus steel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115369212B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102776314A (en) * | 2012-07-24 | 2012-11-14 | 钢铁研究总院 | Smelting method of ultra-low phosphorus steel |
| CN105525055A (en) * | 2014-09-30 | 2016-04-27 | 上海梅山钢铁股份有限公司 | Method for controlling splashing in less slag smelting decarbonization period of converter |
| CN107299181A (en) * | 2017-07-19 | 2017-10-27 | 华北理工大学 | The method of converter gasification dephosphorized slag circulation dephosphorization steel-making |
| JP2019194350A (en) * | 2018-04-27 | 2019-11-07 | 日本製鉄株式会社 | Recycling method of converter slag |
| CN111719032A (en) * | 2019-03-21 | 2020-09-29 | 本钢板材股份有限公司 | Converter less-slag smelting method |
| CN112342334A (en) * | 2020-09-07 | 2021-02-09 | 上海大学 | Method for controlling alkalinity of dephosphorization slag in double-slag converter steelmaking process |
| CN112708717A (en) * | 2020-12-15 | 2021-04-27 | 阳春新钢铁有限责任公司 | Method for smelting low-phosphorus molten steel by single-converter duplex method |
-
2022
- 2022-08-08 CN CN202210943026.4A patent/CN115369212B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102776314A (en) * | 2012-07-24 | 2012-11-14 | 钢铁研究总院 | Smelting method of ultra-low phosphorus steel |
| CN105525055A (en) * | 2014-09-30 | 2016-04-27 | 上海梅山钢铁股份有限公司 | Method for controlling splashing in less slag smelting decarbonization period of converter |
| CN107299181A (en) * | 2017-07-19 | 2017-10-27 | 华北理工大学 | The method of converter gasification dephosphorized slag circulation dephosphorization steel-making |
| JP2019194350A (en) * | 2018-04-27 | 2019-11-07 | 日本製鉄株式会社 | Recycling method of converter slag |
| CN111719032A (en) * | 2019-03-21 | 2020-09-29 | 本钢板材股份有限公司 | Converter less-slag smelting method |
| CN112342334A (en) * | 2020-09-07 | 2021-02-09 | 上海大学 | Method for controlling alkalinity of dephosphorization slag in double-slag converter steelmaking process |
| CN112708717A (en) * | 2020-12-15 | 2021-04-27 | 阳春新钢铁有限责任公司 | Method for smelting low-phosphorus molten steel by single-converter duplex method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115369212B (en) | 2023-10-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102212643B (en) | Converter less-slag smelting process | |
| CN102329921B (en) | Semi-steel making method | |
| CN110129517B (en) | Method for smelting high-silicon iron water based on converter duplex method to improve dephosphorization rate of desiliconization furnace | |
| CN101597664B (en) | Oxygen top-blown converter steelmaking method | |
| CN100500874C (en) | Method of pre-fining molten steel in tapping process | |
| CN101993980A (en) | Method for smelting ultralow-phosphorous steel | |
| CN112126737B (en) | Production method of low-sulfur alloy molten steel | |
| CN110747305B (en) | Converter steelmaking method for producing low-sulfur phosphorus-containing IF steel by using RH single-link process | |
| CN105861775A (en) | Smelting process for ultra-low phosphorus steel with high nickel content | |
| JP3239197B2 (en) | Converter steelmaking method | |
| CN112708717A (en) | Method for smelting low-phosphorus molten steel by single-converter duplex method | |
| CN103627843A (en) | Slagging method in semisteel steelmaking and semisteel steelmaking method | |
| CN107868858A (en) | A kind of production method of low S and low P steel | |
| CN111270041B (en) | Method for reducing phosphorus content in low-phosphorus steel production tapping process of dephosphorization furnace | |
| CN115044741B (en) | Dephosphorization method for low-phosphorus steel double slag in low-silicon high-phosphorus molten iron smelting | |
| CN115369212B (en) | Smelting method of ultralow-phosphorus steel | |
| CN113025781B (en) | Method for producing low-carbon low-silicon ultralow-sulfur steel by adopting LF (ladle furnace) single-link process | |
| CN110982988B (en) | Desulfurization method for promoting contact of steel slag in LF refining furnace and steel-making method | |
| JP2003239009A (en) | Dephosphorization refining method of hot metal | |
| JPH08311519A (en) | Steelmaking method using converter | |
| CN113151633A (en) | Smelting method of ultra-low phosphorus steel | |
| JP3924059B2 (en) | Steelmaking method using multiple converters | |
| CN111926137A (en) | Preparation method for producing ship plate by adopting high-phosphorus, high-arsenic and high-sulfur molten iron | |
| JP3486886B2 (en) | Steelmaking method using two or more converters | |
| CN115369308B (en) | Method for producing high-strength IF steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |