CN117604366A - Preparation method of steel plate casting blank - Google Patents
Preparation method of steel plate casting blank Download PDFInfo
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- CN117604366A CN117604366A CN202311534256.6A CN202311534256A CN117604366A CN 117604366 A CN117604366 A CN 117604366A CN 202311534256 A CN202311534256 A CN 202311534256A CN 117604366 A CN117604366 A CN 117604366A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 105
- 239000010959 steel Substances 0.000 title claims abstract description 105
- 238000005266 casting Methods 0.000 title claims abstract description 73
- 238000002360 preparation method Methods 0.000 title abstract description 8
- 239000002893 slag Substances 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 32
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000009749 continuous casting Methods 0.000 claims abstract description 19
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052786 argon Inorganic materials 0.000 claims abstract description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000001301 oxygen Substances 0.000 claims abstract description 14
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 14
- 238000007664 blowing Methods 0.000 claims abstract description 13
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 238000007670 refining Methods 0.000 claims abstract description 11
- 238000003723 Smelting Methods 0.000 claims abstract description 8
- 229910052742 iron Inorganic materials 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 230000004907 flux Effects 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 14
- 230000008018 melting Effects 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 8
- 230000007547 defect Effects 0.000 abstract description 20
- 238000009628 steelmaking Methods 0.000 abstract description 2
- 230000008092 positive effect Effects 0.000 description 10
- 230000008569 process Effects 0.000 description 9
- 239000010410 layer Substances 0.000 description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000010079 rubber tapping Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 229910052596 spinel Inorganic materials 0.000 description 2
- 239000011029 spinel Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000009957 hemming Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000011158 quantitative evaluation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000007920 subcutaneous administration Methods 0.000 description 1
- 238000009489 vacuum treatment Methods 0.000 description 1
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
- B22D11/181—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
- B22D11/182—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level by measuring temperature
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The application relates to the field of steelmaking production, in particular to a preparation method of a steel plate casting blank. The method comprises the following steps: carrying out converter smelting on molten iron, and controlling the TFe content in ladle top slag to obtain first molten steel; RH vacuum refining is carried out on the first molten steel, and target molten steel is obtained; wherein, controlling the weight ratio of Als to Alt in the target molten steel; obtaining ladle molten steel through the target molten steel, and controlling total oxygen content of the ladle molten steel, als loss amount of the ladle molten steel and weight ratio of Als to Alt of the ladle molten steel to perform continuous casting pouring to obtain a first casting blank; wherein, the technological parameters of continuous casting pouring comprise: the superheat degree of the tundish, the argon blowing flow and the usage amount of the protecting slag; and heating the first casting blank in a furnace, and controlling the surface temperature and the furnace time of the first casting blank when the first casting blank is fed into the furnace to obtain the steel plate casting blank. The method reduces the surface defects of the casting blank and can realize the cleaning-free casting blank.
Description
Technical Field
The application relates to the field of steelmaking production, in particular to a preparation method of a steel plate casting blank.
Background
The high-grade alloyed galvanized sheet has severe requirements on surface defects and inclusion distribution, and a casting blank flame cleaning mode is generally adopted in industrial production to remove more than 3mm of surface so as to reduce the surface defects of a final product. But the bloom flame cleaning increases cost-effectiveness and increases the probability of surface defects from the flame cleaning.
Therefore, there is a need to produce a steel sheet ingot having high surface quality.
Disclosure of Invention
The application provides a preparation method of a steel plate casting blank, which aims to solve the technical problem that the surface defects of the existing high-grade steel plate casting blank are serious.
In a first aspect, the present application provides a method for preparing a steel sheet casting blank, the method comprising:
carrying out converter smelting on molten iron, and controlling the TFe content in ladle top slag to obtain first molten steel;
RH vacuum refining is carried out on the first molten steel, and target molten steel is obtained; wherein, controlling the weight ratio of Als to Alt in the target molten steel;
obtaining ladle molten steel through the target molten steel, and controlling total oxygen content of the ladle molten steel, als loss amount of the ladle molten steel and weight ratio of Als to Alt of the ladle molten steel to perform continuous casting pouring to obtain a first casting blank; wherein, the technological parameters of continuous casting pouring comprise: the superheat degree of the tundish, the argon blowing flow and the usage amount of the protecting slag;
and heating the first casting blank in a furnace, and controlling the surface temperature and the furnace time of the first casting blank when the first casting blank is fed into the furnace to obtain the steel plate casting blank.
Optionally, the weight content of TFe in the ladle top slag is 2% -4%.
Optionally, the weight ratio of Als to Alt in the target molten steel is more than or equal to 90%.
Optionally, the total oxygen content of the tundish molten steel is less than or equal to 15ppm.
Optionally, the Als loss of the ladle molten steel is less than or equal to 80ppm, and the weight ratio of Als to Alt of the ladle molten steel is more than or equal to 90%.
Optionally, the superheat degree of the tundish is more than or equal to 30 ℃.
Optionally, the argon blowing flow is less than or equal to 3L/min.
Optionally, the usage amount of the mold flux includes: the thickness of the slag layer at the 1/4 position in the width direction under the condition that the fluctuation of the liquid level of the crystallizer is +/-5 mm is more than or equal to 10mm.
Optionally, the physical characteristics of the mold flux include: the melting point is 1150-1210 ℃ and the viscosity is 0.35-0.50 Pa.s.
Optionally, the surface temperature of the first casting blank is more than or equal to 600 ℃ when the first casting blank is fed into the furnace, and the furnace time is more than or equal to 160min.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the preparation method of the steel plate casting blank, the TFe in the steel slag and the total oxygen content in the steel are controlled, so that the high cleanliness of molten steel is ensured; through quantitative evaluation of Als/Alt in molten steel and process aluminum loss, the adequate floating of inclusions in the steel is ensured; through high overheat pouring, low flow argon blowing and full liquid slag protection, the stable and controllable size and subcutaneous depth of inclusion on the surface layer of the casting blank are realized; the stable control of the iron sheet burning loss is realized by the two steps of the temperature of the high-temperature casting blank entering the furnace and the residence time of the high-temperature casting blank in the heating furnace, and the inclusion of the shallow surface layer of the casting blank is eliminated. The method has the advantages that the surface defects of the casting blank are reduced by comprehensively controlling the smelting and continuous casting processes, the product surface defects caused by the quality problem of the casting blank are effectively reduced, the cleaning-free casting blank can be realized, and the production cost is saved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic flow chart of a method for preparing a steel plate casting blank according to an embodiment of the present application.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
Various embodiments of the present application may exist in a range format; it should be understood that the description in a range format is merely for convenience and brevity and should not be interpreted as a rigid limitation on the scope of the application. It is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In this application, unless otherwise indicated, terms of orientation such as "upper" and "lower" are used specifically to refer to the orientation of the drawing in the figures. In addition, in the description of the present application, the terms "include", "comprise", "comprising" and the like mean "including but not limited to". Relational terms such as "first" and "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Herein, "and/or" describing an association relationship of an association object means that there may be three relationships, for example, a and/or B, may mean: a alone, a and B together, and B alone. Wherein A, B may be singular or plural. Herein, "at least one" means one or more, and "a plurality" means two or more. "at least one", "at least one" or the like refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
Unless specifically indicated otherwise, the various raw materials, reagents, instruments, equipment, and the like used in this application are commercially available or may be prepared by existing methods.
In a first aspect, the present application provides a method for preparing a steel sheet casting blank, referring to fig. 1, the method includes:
s1, carrying out converter smelting on molten iron, and controlling the TFe content in ladle top slag to obtain first molten steel;
in some embodiments, the weight content of TFe in the ladle top is 2% -4%.
In the embodiment of the application, the aluminum-containing slag modifier is added near the end of converter tapping, the adding amount is determined according to the estimated slag discharging amount of the converter and the target of 2% -4% of TFe content in the modified slag, and the adding time is the finishing of the adding of the modifier after the converter tapping. The positive effect of controlling the weight content of TFe in the ladle top slag to be 2% -4%: can effectively reduce the oxidizing property of slag and does not lead to magnesia-alumina spinel in steel. If the TFe content is too much, steel slag oxidizing molten steel can be aggravated to a certain extent, aluminum oxide inclusion in the steel is increased, and if the TFe content is too little, the production cost of the steel can be increased to a certain extent, magnesia-alumina spinel inclusion is generated in the steel, and a water inlet is blocked during continuous casting. Specifically, the weight content of TFe in the ladle top slag may be 2%, 3%, 4%, etc.
S2, carrying out RH vacuum refining on the first molten steel to obtain target molten steel; wherein, controlling the weight ratio of Als to Alt in the target molten steel;
in the embodiment of the application, the RH technology is adopted for refining, aluminum deoxidation and alloying are completed by adding aluminum once, and the pure circulation time of the last batch is 4-6min.
In some embodiments, the weight ratio of Als to Alt in the target molten steel is ≡90%.
In the embodiment of the application, sampling analysis is performed near the refining end, the ratio of Als/Alt is more than or equal to 90%, otherwise, vacuum treatment is continued. The positive effect of controlling the weight ratio of Als to Alt in the molten steel after refining to be more than or equal to 90 percent is that: so that the aluminum oxide inclusion in the molten steel is reduced. If the weight ratio of Als to Alt is too small, inclusions of aluminum oxide in molten steel are increased to some extent, and clogging of a submerged nozzle occurs during continuous casting. Specifically, the weight ratio of Als to Alt in the target molten steel may be 90%, 92%, 94%, 96%, 98%, etc.
S3, obtaining ladle molten steel through the target molten steel, and controlling total oxygen content of the ladle molten steel, als loss amount of the ladle molten steel and weight ratio of Als to Alt of the ladle molten steel to perform continuous casting pouring to obtain a first casting blank; wherein, the technological parameters of continuous casting pouring comprise: the superheat degree of the tundish, the argon blowing flow and the usage amount of the protecting slag;
in the embodiment of the application, the continuous casting adopts full-protection pouring
In some embodiments, the total oxygen content (TO) of the tundish molten steel is 15ppm or less.
In the embodiment of the application, the positive effect of controlling the total oxygen content of the ladle molten steel to be less than or equal to 15ppm is as follows: the mass percentage of free oxygen and oxygen-containing inclusions in the steel is reduced. If the total oxygen content is too high, the method characterizes that the number density of various oxide inclusions in the steel is high to a certain extent, and the water mouth is easy to be blocked during continuous casting. Specifically, the total oxygen content of the tundish molten steel may be 15ppm, 14ppm, 13ppm, 12ppm, 11ppm, 10ppm, etc.
In some embodiments, the amount of Als lost in the ladle of molten steel is 80ppm or less, and the weight ratio of Als to Alt in the ladle of molten steel is 90% or more.
In the embodiment of the application, the positive effect of controlling the Als loss of the ladle molten steel to be less than or equal to 80ppm is as follows: oxidation of molten steel from refining to continuous casting is stable and controllable. If the Als loss is too large, the serious secondary oxidization of the molten steel is represented to a certain extent, and oxide inclusion in the molten steel is in an abnormal rising process. Specifically, the Als loss amount of the ladle molten steel may be 80ppm, 75ppm, 70ppm, etc.
In some embodiments, the superheat of the tundish is ≡30 ℃.
In the embodiment of the application, the refining temperature is controlled by the superheat degree of the continuous casting process being more than or equal to 30 ℃. The positive effect of controlling the superheat degree of the tundish to be more than or equal to 30 ℃ is that: the inclusion in the molten steel has better floating condition, and a shorter solidification hook is arranged when the crystallizer is cooled, so that the positive effect is achieved on the melting of the casting powder and the uniform spreading of the liquid slag. If the superheat is too low, slag defects on the surface of the coil are increased to some extent. Specifically, the superheat degree of the tundish may be 30 ℃, 34 ℃, 38 ℃, 40 ℃, or the like.
In some embodiments, the argon blowing flow is ∈3L/min.
In the embodiment of the application, the positive effect of controlling the argon blowing flow to be less than or equal to 3L/min is that: the argon amount and the size of bubbles blown into the crystallizer can be reduced, and the stopper rod and the water inlet are limited by low-flow argon blowing; if the argon blowing flow is too high, the flow of molten steel of the crystallizer can be excessively disturbed to a certain extent, and the slag at the top of the crystallizer is seriously emulsified, so that the slag rolling defect on the surface of the coiled plate is greatly increased. Specifically, the argon blowing flow may be 3L/min, 2.8L/min, 2.5L/min, 2.3L/min, 2L/min, etc.
In some embodiments, the amount of the mold flux includes: the thickness of the slag layer at the 1/4 position in the width direction under the condition that the fluctuation of the liquid level of the crystallizer is +/-5 mm is more than or equal to 10mm.
In the embodiment of the application, the thickness of the slag layer at 1/4 position in the width direction under the condition that the fluctuation of the liquid level of the crystallizer is within +/-5 mm is set
Not less than 10mm, its purpose is: when the fluctuation of the liquid level of the crystallizer is in a normal range, the process of converting molten steel into an initial setting billet shell is in effective liquid slag protection. Specifically, the thickness of the slag layer at the 1/4 position in the width direction under the condition that the fluctuation of the liquid level of the crystallizer is within + -5 mm can be 10mm, 12mm, 14mm, 16mm and the like.
In some embodiments, the physical characteristics of the mold flux include: the melting point is 1150-1210 ℃ and the viscosity is 0.35-0.50 Pa.s.
In the embodiment of the application, the positive effect of controlling the melting point of the covering slag to 1150-1210 ℃ is that: ensuring good molten state of the mold flux. If the melting point of the mold flux is too high, the mold flux is difficult to melt to a certain extent, and the mold flux liquid slag layer in the crystallizer is thin; if the melting point of the mold flux is too low, the fluidity of the slag is increased to some extent, so that the liquid slag drops are easily involved in the molten steel. Specifically, the melting point of the mold flux may be 1150 ℃, 1170 ℃, 1180 ℃, 1200 ℃, 1210 ℃, or the like.
Positive effect of controlling the viscosity of the mold flux to be 0.35pa.s-0.50 pa.s: ensures that the casting powder can effectively lubricate the casting blank and the crystallizer copper plate, and controls the reasonable thickness of the liquid slag layer. If the viscosity of the casting powder is too high, lubrication between the casting blank and the copper plate of the crystallizer can be deteriorated to a certain extent, so that the casting blank and the copper plate are bonded; if the viscosity of the mold flux is too low, the consumption of the liquid slag is increased to a certain extent, so that the thickness of the liquid slag layer of the crystallizer is greatly reduced, and the slag coiling defect is increased. Specifically, the viscosity of the mold flux may be 0.35pa.s, 0.40pa.s, 0.45pa.s, 0.50pa.s, etc.
And S4, heating the first casting blank in a furnace, and controlling the surface temperature and the furnace time of the first casting blank when the first casting blank is fed into the furnace to obtain the steel plate casting blank.
In some embodiments, the surface temperature of the first strand at the time of charging is no less than 600 ℃, and the charging time is no less than 160 minutes.
In the embodiment of the application, the surface temperature of the first casting blank is controlled to be more than or equal to 600 ℃ when the first casting blank is fed into the furnace: the fluctuation of the burning loss of the iron sheet of the casting blank is reduced, and the casting blank is required to be heated in a Wen Zhuangru heating furnace; if the surface temperature of the casting blank is too low, the burning loss of the casting blank in the heating furnace can be reduced to a certain extent. Specifically, the surface temperature of the first cast slab at the time of the charging may be 600 ℃, 620 ℃, 640 ℃, 650 ℃, 680 ℃, 700 ℃, or the like.
The positive effect of controlling the furnace time to be more than or equal to 160min is that: stabilizing the burning loss of the casting blank in the heating furnace, wherein the casting blank has higher heat; if the furnace time is too short, the burning loss of the cast slab in the heating furnace is reduced to some extent, so that the surface inclusion defects are increased, and the fine line defects are generated at the plate hemming portion due to the increase of the temperature drop of the corner portion of the cast slab. Specifically, the in-furnace time may be 160 ℃, 165 ℃, 170 ℃, 180 ℃, or the like. In addition, the tapping temperature heated in the furnace is more than or equal to 1180 ℃.
By the method, the depth fluctuation condition of the inclusion on the surface layer of the casting blank is effectively controlled and identified, the iron sheet falling off and burning loss of the casting blank are controlled, the surface defects of the casting blank are reduced, the surface defects of products caused by the quality problem of the casting blank are effectively reduced, and the cleaning-free casting blank can be realized. And carrying out subsequent rolling, galvanization and other processes on the steel plate casting blank, so that the high-grade alloyed galvanized plate with good surface quality can be obtained.
The present application is further illustrated below in conjunction with specific examples. It should be understood that these examples are illustrative only of the present application and are not intended to limit the scope of the present application. The experimental procedures, which are not specified in the following examples, are generally determined according to national standards. If the corresponding national standard does not exist, the method is carried out according to the general international standard, the conventional condition or the condition recommended by the manufacturer.
The embodiment of the application provides a preparation method of a steel plate casting blank, which comprises the following steps:
s11, carrying out converter smelting on molten iron, and controlling the TFe content in ladle top slag to obtain first molten steel;
s21, carrying out RH vacuum refining on the first molten steel to obtain target molten steel; wherein, controlling the weight ratio of Als to Alt in the target molten steel;
s31, obtaining ladle molten steel through the target molten steel, and controlling total oxygen content of the ladle molten steel, als loss amount of the ladle molten steel and weight ratio of Als to Alt of the ladle molten steel to perform continuous casting pouring to obtain a first casting blank; wherein, the technological parameters of continuous casting pouring comprise: the superheat degree of the tundish, the argon blowing flow and the usage amount of the protecting slag;
and S41, heating the first casting blank in a furnace, and controlling the surface temperature and the furnace time of the first casting blank when the first casting blank is fed into the furnace to obtain the steel plate casting blank. For specific process parameters, see tables 1-2.
TABLE 1 Process parameters for converter smelting, RH refining and continuous casting
TABLE 2 Process parameters for heating billets
| Sequence number | Surface temperature of casting blank when entering furnace | Total heating time min | Tapping temperature (DEG C) |
| Example 1 | 600 | 160 | 1180 |
| Example 2 | 700 | 170 | 1182 |
| Example 3 | 650 | 165 | 1185 |
| Comparative example 1 | 350 | 145 | 1180 |
The cast slabs prepared in examples 1 to 3 and comparative example 1 were subjected to the evaluation of surface defects of the cast slabs, and the results are shown in Table 3.
TABLE 3 evaluation results of surface defects of cast slabs
| Sequence number | Defect rate% |
| Example 1 | 5.10 |
| Example 2 | 6.12 |
| Example 3 | 3.39 |
| Comparative example 1 | 13.67 |
According to the analysis of the table 1-table 3, the preparation method of the steel plate casting blank provided by the application is comprehensively controlled in smelting and continuous casting procedures, so that the surface defects of the casting blank are reduced, the product surface defects caused by the quality problem of the casting blank are effectively reduced, and the cleaning-free of the casting blank can be realized; in comparative example 1, the defect rate of the cast slab was high without using the method of the present example.
The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for producing a steel sheet ingot, comprising:
carrying out converter smelting on molten iron, and controlling the TFe content in ladle top slag to obtain first molten steel;
RH vacuum refining is carried out on the first molten steel, and target molten steel is obtained; wherein, controlling the weight ratio of Als to Alt in the target molten steel;
obtaining ladle molten steel through the target molten steel, and controlling total oxygen content of the ladle molten steel, als loss amount of the ladle molten steel and weight ratio of Als to Alt of the ladle molten steel to perform continuous casting pouring to obtain a first casting blank; wherein, the technological parameters of continuous casting pouring comprise: the superheat degree of the tundish, the argon blowing flow and the usage amount of the protecting slag;
and heating the first casting blank in a furnace, and controlling the surface temperature and the furnace time of the first casting blank when the first casting blank is fed into the furnace to obtain the steel plate casting blank.
2. The method of claim 1, wherein the ladle top slag has a TFe content of 2% -4% by weight.
3. The method of claim 1, wherein the weight ratio of Als to Alt in the target molten steel is equal to or greater than 90%.
4. The method of claim 1, wherein the tundish molten steel has a total oxygen content of
≤15ppm。
5. The method according to claim 1 or 4, wherein the Als loss of the ladle molten steel is not more than 80ppm, and the weight ratio of Als to Alt of the ladle molten steel is not less than 90%.
6. The method of claim 1, wherein the tundish superheat is greater than or equal to 30 ℃.
7. The method of claim 1, wherein the argon blowing flow is 3L/min or less.
8. The method according to claim 1, wherein the amount of the mold flux includes: the thickness of the slag layer at the 1/4 position in the width direction under the condition that the fluctuation of the liquid level of the crystallizer is +/-5 mm is more than or equal to 10mm.
9. The method according to claim 1 or 8, wherein the physical characteristics of the mold flux include:
the melting point is 1150-1210 ℃ and the viscosity is 0.35-0.50 Pa.s.
10. The method according to claim 1, wherein the surface temperature of the first cast slab at the time of charging is not less than 600 ℃, and the charging time is not less than 160 minutes.
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