CN108677084A - A kind of low production method for being mingled with clean steel - Google Patents

A kind of low production method for being mingled with clean steel Download PDF

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CN108677084A
CN108677084A CN201810305245.3A CN201810305245A CN108677084A CN 108677084 A CN108677084 A CN 108677084A CN 201810305245 A CN201810305245 A CN 201810305245A CN 108677084 A CN108677084 A CN 108677084A
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slag
steel
pass
content
rolling temperature
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CN108677084B (en
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张素英
张觉灵
杨海西
曹喜军
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Jingye Steel Co Ltd
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Jingye Steel Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • 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
    • C21C5/28—Manufacture of steel in the converter
    • 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
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/36—Processes yielding slags of special composition
    • 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
    • C21C7/0645—Agents used for dephosphorising or 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
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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  • Heat Treatment Of Steel (AREA)

Abstract

A kind of low production method for being mingled with clean steel, prepares Steel material, and meet the following conditions according to the specified ratio：The Carbonitride Precipitation object of Nb, Ti, Mo in steel, Nb: Ti: Mo atomic ratio is 4: 1: 0.2 in the precipitate, and precipitate grain size is 40 60nm, the bainite that final tissue is 97% or more with area occupation ratio statistics, ferrite, pearlite area occupation ratio are 3% hereinafter, 25 μm of average grain size；Yield strength is 730 810MPa, and tensile strength is 850 930MPa, and 40 DEG C of impact flexibility are 110 130J, and elongation percentage is 17 20%.

Description

A kind of low production method for being mingled with clean steel
Technical field
The invention belongs to technical field of metal material, and in particular to a kind of low production method for being mingled with clean steel.
Background technology
Clean steel production is one of the important directions of steel-smelting technology development the 1990s, and impurity in clean steel to steel There is the content of element very strict requirement, the mass fraction generally requirement of sulphur, phosphorus to be not more than 0.01%.To hydrogen, oxygen and The content of low-melting-point metal also has quite stringent control requirement.To reach requirement, now to clean steel Study on Smelting Process master To include 2 aspects：Reduce the content of impurity element in steel as far as possible by new process；Non- gold in steel is strictly controlled by new technology Belong to the quantity and form of field trash.The former is the top priority of current clean steel research.
In any case, nitrogen in steel element can reduce the performance of steel material.Due to the presence of nitrogen, the tough of steel is reduced Property, welding performance, thermal stress area toughness, cause steel brittleness increase；Another aspect nitrogen can cause casting blank cleavage, thus control steel In nitrogen content be clean steel production necessary condition.Since the ionic radius of nitrogen is bigger than hydrogen, the diffusion coefficient in steel compares hydrogen Small 2 orders of magnitude, vacuum denitrification effect is poor, and the nitride that nitrogen is formed with most of alloying elements will divide at high temperature Solution can not be removed by floating.In addition to this, certain supplementary materials bring nitrogen into, the nitrogen pick-up of LF refining arc region, deoxidation molten steel with it is big Gas, which contacts, inhales nitrogen, and the reasons such as removal of presence obstruction nitrogen of oxygen, sulphur make nitrogen be difficult to control in reduced levels in steel, are given birth to clean steel Production exerts a certain influence.
The production of clean steel be not only need control N, further include to nonmetallic inclusionsin steel (mainly oxide, Sulfide) steel grade that is strictly controlled, it is desirable that total oxygen content is low in steel, and non-metallic inclusion quantity is few, size is small, distribution is equal Even, brittle inclusion is few and suitable field trash shape.External some steels power (such as Japan, the U.S., Germany) is in recent years Relevant research is carried out successively to put into huge fund, has been made great progress.Since the 1980s, China introduces successively The modernization corollary equipment and technology of a collection of production clean steel, have the ability of production clean steel.But it is in general, just clean For net steel production, that there are equipments is low for China's steel, product structure is poor, and quality mind is not strong, technical merit is more low asks Topic.Clean steel production is comprehensive raising China's steel products quality scale, and first with high efficiency continuous casting, newly net forming continuous casting and rolling etc. It is combined into technology, realizes the only way strided forward to steel power and one of the important signs that.
With the continuous improvement of metallurgical technology level, the content of impurity element is effectively controlled in steel, especially oxygen, sulphur Content can reach 0.005%, even lower so that the production of clean steel becomes possible to.Clean steel is widely used in household electrical appliances, vapour Vehicle, acid and alkali-resistance pipeline and other purposes extremely under harsh conditions.The component type of steel inclusion, form, distribution and The factors such as size all to some extent have an impact steel performance, and field trash has become an important finger for weighing steel performance Mark.
Invention content
Technical problem solved by the invention be to provide it is a kind of it is low be mingled with clean steel production method, can produce with high-strength Degree, high tenacity, low yield strength ratio, crack sensitivity are low, inclusion content is low, inclusion size is small, excellent Resistant to HIC it is excellent Point.To achieve the above object, one aspect of the present invention needs to control the ingredient of steel, on the other hand needs the production method for controlling steel.
Technical solution is as follows：
A kind of low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C 0.012-0.015%, Si 0.15-0.18%, Mn 0.85-0.88%, P≤0.005%, S≤0.005%, Nb 0.045-0.055%, Ti 0.010- 0.012%, Al≤0.005%, Cr 1.85-1.95%, Mo 0.65-0.75%, Ni 2.55-2.65%, Cu 0.15- 0.19%, W 0.005-0.008%, Zr 0.0001-0.0004%, Ta 0.0001-0.005%, rare earth La+Y 0.0001- 0.0005%, La: Y mass ratio is 2: 1, B 0.0001-0.0005%, N 0.001-0.005%, N/Al 1.2-1.4, surplus For Fe and inevitable impurity element, the Carbonitride Precipitation object of Nb, Ti, Mo are formd, Nb: Ti: Mo is former in the precipitate For son than being 4: 1: 0.2, precipitate grain size is 40-60nm, the bainite that final tissue is 97% or more with area occupation ratio statistics, iron element Body, pearlite area occupation ratio are 3% hereinafter, 2-5 μm of average grain size；Yield strength is 730-810MPa, and tensile strength is 850-930MPa, -40 DEG C of impact flexibility are 110-130J, elongation percentage 17-20%；
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*t-1, later stage argon flow amount is 0.15-0.2Nm3/min*t-1, carbon content Target≤0.04%, phosphorus content≤0.015%, converter finishing slag basicity are 3.45-3.5, and tapping temperature is 1650-1670 DEG C；It adopts With floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Further：The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C 0.012%, Si 0.15%, Mn 0.85%, P 0.001%, S 0.001%, Nb 0.045%, Ti 0.01%, Al 0.002%, Cr 1.85%, Mo 0.65%, Ni 2.55%, Cu 0.15%, W 0.005%, Zr 0.0001%, Ta 0.0001%, rare earth La+Y 0.0001%, La: Y mass ratio are 2: 1, B 0.0001%, N 0.0025%, and surplus is Fe and inevitable impurity Element.
Further：The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C0.015%, Si 0.18%, Mn 0.88%, P 0.005%, S 0.005%, Nb 0.055%, Ti 0.012%, Al 0.004%, Cr 1.95%, Mo 0.75%, Ni 2.65%, Cu 0.19%, W 0.008%, Zr 0.0004%, Ta 0.005%, rare earth La + Y 0.0005%, La: Y mass ratio are 2: 1, B 0.0005%, N 0.005%, and surplus is Fe and inevitable impurity member Element.
Further：The low production method for being mingled with clean steel, it is characterised in that：Step (2) converter smelting：Select 200t Converter, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), S content≤0.005%, C content in steel scrap≤ 0.07%, oxidizing slag content is 15.5wt% in slag, molten iron: steel scrap: the mass ratio of slag is 15: 1: 1.2, first plus steel scrap, Hot metal charging afterwards finally adds slag, and using double slag operation, bottom-blowing of converter argon gas and nitrogen, early period, nitrogen intensity was 0.08Nm3/ min*t-1, later stage argon flow amount is 0.18Nm3/min*/t-1, carbon content target≤0.04%, phosphorus content≤0.015%, converter Finishing slag basicity is 3.48, and tapping temperature is 1660 DEG C；Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds 5.3kg/t Lime and the fluorite of 1.8kg/t make top slag.
Further：The low production method for being mingled with clean steel, it is characterised in that：Step (3) is first added 0.23kg/t's The lime of aluminium powder, the fluorite of 0.25kg/t, the Fe-30Si powder of 0.25kg/t, 1.5kg/t first controls BOTTOM ARGON BLOWING flow and exists 530L/min is adjusted to 185L/min after lime fusing, stops being powered after the complete white slag of clinker, makes white slag target component： CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow stirs 12min in this case in 830L/min, controls BOTTOM ARGON BLOWING flow later in 130L/min, in this shape 10min is stirred under state, is once again powered up adjustment bath temperature convenient for tapping, soft blow stops Argon, terminates LF refining.
Further：The low production method for being mingled with clean steel, it is characterised in that：Step (5) heats and rolling；By thickness Heating furnace is put into for the slab of 50mm, 1180~1185 DEG C of heating temperature, heating time 50-60min, the first stage is austenite Recrystallization zone rolls, and specifically the first passage start rolling temperature is 1120 DEG C, and the first reduction in pass is 10.5mm, and the second passage is opened It is 1070 DEG C to roll temperature, and the second reduction in pass is 9.5mm, and third passage start rolling temperature is 1030 DEG C, third reduction in pass For 7.5mm, four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5.5mm, and the 5th passage start rolling temperature is 870 DEG C, the 5th reduction in pass is 3.5mm；Second stage rolls for austenite Unhydrated cement, specifically the first passage open rolling temperature Degree is 820 DEG C, and the first reduction in pass is 3mm, and the second passage start rolling temperature is 770 DEG C, and the second reduction in pass is 1.5mm.
Compared with prior art, the technology of the present invention effect includes：
1, the present invention is by accurately controlling finish rolling start rolling temperature, ensure tissue slab transverse direction, longitudinal tissue, performance it is equal Even property, and list rolling pass reduction system.With good weldability while with high intensity, high tenacity.
2, in the present invention, steel is produced in hot continuous rolling production line, by being accurately controlled to alloying element, is avoided to increase Alloy quantity exchanges the raising of performance for, has saved process costs, improves production efficiency.
3, the present invention is by rational Design of Chemical Composition, and takes cooling controlling and rolling controlling process, obtains finally organizing with area Rate statistics is 97% or more bainite, and ferrite, pearlite area occupation ratio are 3% hereinafter, 2-5 μm of average grain size；Surrender Intensity is 730-810MPa, and tensile strength 850-930MPa, -40 DEG C of impact flexibility are 110-130J, elongation percentage 17- 20%.
4, the present invention is stirred by strengthening molten iron pretreatment desulfurizing, top and bottom complex blowing, bottom blown gas, molding casting, is adopted With the oxidisability or oxygen content of the technological means reduction slags such as floating plug, the double slag-stopping tappings of scum rod to reduce the life of field trash At；Reduce the condition of field trash formation by LF refining technique, RH refining controlling air blowings flow, line feeding amount, the selection on opportunity, Positive simultaneously makes inclusion floating exclude.
Then, illustrate the restriction reason of the chemical composition of the present invention.Herein, mean quality % about the % of ingredient.
C is element necessary to target strength, microscopic structure in order to obtain, for improving by accelerating the cooling steel plate manufactured The most effective element of intensity.But cannot ensure enough intensity if C amounts are less than 0.012%, on the other hand, if being more than 0.015% toughness and Resistant to HIC are deteriorated, and the carbide for becoming destruction starting point is largely formed, and degraded toughness is not only resulted in, scene Weldability is also significantly deteriorated.Therefore, the additive amount of C is set as C 0.012-0.015%.
Si has the effect of the precipitation for inhibiting to become the carbide for destroying starting point, although Si adds for deoxidation, Toughness, weldability are deteriorated if Si amounts are more than 0.18%.Therefore Si 0.15-0.18%.
Mn is solution strengthening element, and Mn is intensity in order to improve steel and toughness and adds, if but Mn amounts are less than 0.85% Then its effect is insufficient, and weldability and Resistant to HIC are deteriorated in addition, making austenite region temperature be expanded to if more than 0.88% In cooling after the rolling of low temperature side, has and be easy to get the continuous of one of constitutive requirements as microscopic structure of the present invention The effect of cooling phase-change tissue, so Mn 0.85-0.88%.
P is inevitable impurity element, keeps Resistant to HIC variation more lower more excellent due to making the hardness in center segregation portion rise If choosing is segregated in the central part of continuously casting steel disc containing having more than 0.03%, causes intercrystalline failure, significantly reduces low temperature Toughness, therefore it is set as 0.03% or less.In turn, P to the weldability of tubing and scene due to bringing harmful effect, it is contemplated that arriving When the above problem, preferably 0.005% or less.
S is usually formed the field trash of MnS classes in steel, but can carry out being converted into CaS type impurities by MnS classes by adding Ca Form control.But if the amount of S amounts at most CaS type impurities also increases, become the starting point of crackle in high-strength material. Therefore content is 0.005% or less.Nb, Ti are one of elements important in the present invention.Nb has the following effects that：Its by Towing effect under solid solution condition and/or the pinning effect as carbon nitridation precipitate, inhibit the Ovshinsky in rolling or after rolling The recovery and recrystallization and grain of body are grown, disconnected in the crevasse crack propagation by reducing brittle break by effective crystal particle diameter grain refined Face unit, makes low-temperature flexibility improve.In turn, it is generated in the coiling process as the feature of hot rolled steel plate manufacturing process fine Carbide is conducive to improve intensity because of its precipitation strength.Also, Nb has the following effects that：Make γ/α phase change delays, by making Phase transition temperature reduces, and the microscopic structure after phase transformation is also made steadily to become continuous cooling transformation group under slow cooling velocity It knits.But these effects in order to obtain, it is necessary at least add 0.045% or more.On the other hand, when addition is more than 0.055%, Not only its effect is saturated, but also is difficult to make its solid solution in the heating process before hot rolling, to forming coarse carbonitride As the starting point of destruction, it is possible to low-temperature flexibility, acid resistance be made to be deteriorated.Therefore Nb 0.045-0.055%.
It is used as nitride at a high temperature of Ti is after the strand cast by continuously casting or steel ingot just solidification to start to be precipitated.Contain There is the precipitate of the Ti nitride to stablize at high temperature, also not exclusively solid solution, plays pinning effect in follow-up slab reheating, Microscopic structure miniaturization is improved low-temperature flexibility by the coarsening of the austenite grain in inhibiting slab to reheat.In addition, in γ/α Inhibit to generate ferritic core in phase transformation, has the effect of promoting to generate the continuous cooling transformation tissue as important document of the present invention. Said effect in order to obtain, it is necessary to the Ti of addition at least 0.01% or more.On the other hand, even if addition is more than 0.012%, the effect Fruit is also saturated.Due to imperceptibly crystallizing or being precipitated using these precipitates of fine oxide as core and containing Ti nitride, because This makes the average equivalent circular diameter of the precipitate containing Ti nitride become smaller, and not only inhibits in rolling because of the effect of intensive dispersion Or the recovery and recrystallization of the austenite after rolling, also inhibit the ferritic grain growth after batching, so Ti 0.010- 0.012%.
The microalloy elements such as Nb, Ti are added in steel of the present invention, can be played：Austenite Grain Growth is prevented when heating；It is rolling The crystal grain after recrystallization and recrystallization is inhibited to grow up in the process；Play precipitation strength in middle low temperature.
Al is required for deoxidation.But when more containing quantitative change, then toughness is easy to be deteriorated especially in HAZ.This be because To be easy to form the alumina type inclusion particle of coarse tufted.For this purpose, the content of Al is set as 0.005% or less.It is more excellent Select 0.001~0.005%.
N contributes to the grain refined of tissue because forming nitride, however in the case where adding too much, then it can be because of nitride It agglomerates and toughness is made to deteriorate.So the content of N is set as 0.001~0.005%.By being 1.2-1.4 by the control of N/Al ratios, The harmful effect being precipitated after coarse A1N to toughness is avoided, the Dispersed precipitate of TiN is not interfered with, large-line energy may be implemented HAZ toughness, the especially improvement of connector CTOD characteristics.
Cr is by improving quenching degree to the effective element of the raising of intensity, in order to obtain its content of the effect be 1.85% with On.Cr amounts weldability if more than 1.95% is deteriorated.Therefore, Cr 1.85-1.95%.
Mo has the effect of that hardenability is made to improve, intensity is made to increase, and is the effective element of raising of the improvement and intensity to toughness. In addition, Mo coexists with Nb, austenite structure miniaturization is had and is carried by the strong recrystallization for inhibiting the austenite in controlled rolling The effect of high/low temperature toughness.But even if addition is saturated more than 0.75% if its effect, therefore it is set as 0.75% or less.Separately Outside, when adding 0.65% or more, ductility reduction, it is possible to make weldability reduce, therefore Mo 0.65-0.75%.
Ni is the effective element of raising of the improvement and intensity to toughness, have do not make low-temperature flexibility or site welding be deteriorated and Improve the effect of intensity.Content is more than 2.65%, and effect is also saturated, but weldability starts to reduce, therefore is set as Ni 2.55- 2.65%.
Cu has the effect of improving corrosion resistance, resistance to hydrogen induced cracking characteristic.0.15% or more should be at least added, still, i.e., It is more than 0.19% to make addition, and effect is also saturated, therefore Cu 0.15-0.19%.
W is to form carbide and nitride while improving hardenability to improve the element of intensity.Its effect in order to obtain, Need the W of 0.005% or more addition.But the addition of a large amount of W more than 0.008% makes needed for the intensity of base material increases to More than, and toughness is made to significantly reduce.Therefore, the range of W amounts is defined as 0.005-0.008%
Zr and Nb is again it is have the effect of improving the element of intensity by forming carbide and nitride.But 0.0001% or less when adding, without its effect.In addition, when addition is more than 0.0004% Zr, toughness is caused to reduce.Therefore Zr is defined as 0.0001.-0.0004%.
Ta and Nb is again it is have the effect of improving the element of intensity by forming carbide and nitride.But 0.0001% or less when adding, without its effect.In addition, when addition is more than 0.00050% Ta, toughness is caused to reduce.Cause Ta is defined as 0.0001-0.005% by this.
B has the effect of improving hardenability, is easy to get continuous cooling transformation tissue.In turn, there is B the hardenability for improving Mo to change It is apt to effect while is coexisted with Nb synergistically to increase the effect of hardenability.Therefore, it is necessary to add B 0.0001~0.0005；Cause When to add more than 0.0005%, slab crackle occurs.
It is the element being modified to non-metallic inclusion that RE, which is common, at the same can also crystal grain thinning, improve the pinning effect of oxide Or resistance to lamellar tearing, improve intensity and toughness.But even if without the effect if addition is less than 0.0001%；Addition is more than When 0.0005%, cost can increase.It is 2: 1 that the application rare earth RE, which is La+Y 0.0001-0.0005%, La: Y mass ratio,.
Oxidizing slag content is 15-16wt% in slag, is conducive to the progress that converter takes off P.
Specific implementation mode
It elaborates to technical solution of the present invention below with reference to example embodiment.However, example embodiment can Implement in a variety of forms, and is not understood as limited to embodiment set forth herein；On the contrary, thesing embodiments are provided so that The design of example embodiment more comprehensively and completely, and is comprehensively communicated to those skilled in the art by the present invention.
Embodiment 1
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is that composition of steel is C 0.012%, Si 0.15%, Mn 0.85%, P 0.001%, S 0.001%, Nb 0.045%, Ti 0.01%, Al 0.002%, Cr 1.85%, Mo 0.65%, Ni 2.55%, Cu 0.15%, W 0.005%, Zr 0.0001%, Ta 0.0001%, rare earth La+Y 0.0001%, La: Y mass ratio are 2: 1, B 0.0001%, N 0.0025%, and surplus is Fe and inevitable impurity Element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: the matter of slag in slag It is 15: 1: 1.2 to measure ratio, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen, Early period, nitrogen intensity was 0.06-0.1Nm3/min*t-1, later stage argon flow amount is 0.15-0.2Nm3/min*t-1, carbon content target ≤ 0.04%, phosphorus content≤0.015%, converter finishing slag basicity is 3.45-3.5, and tapping temperature is 1650-1670 DEG C；Using gear The double slag-stopping tappings of slag plug, scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Embodiment 2
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C0.013%, Si 0.16%, Mn 0.86%, P 0.003%, S 0.002%, Nb 0.05%, Ti 0.011%, Al 0.003%, Cr 1.9%, Mo 0.7%, Ni 2.6%, Cu 0.17%, W 0.006%, Zr 0.0002%, Ta 0.002%, rare earth La+Y 0.0002%, La: Y matter For amount than being 2: 1, B 0.0003%, N 0.004%, surplus is Fe and inevitable impurity element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon flow amount is 0.15-0.2Nm3/min*t-1, carbon content Target≤0.04%, phosphorus content≤0.015%, converter finishing slag basicity are 3.45-3.5, and tapping temperature is 1650-1670 DEG C；It adopts With floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Embodiment 3
The low production method for being mingled with clean steel, it is characterised in that：C0.015%, Si 0.18%, Mn 0.88%, P0.005%, S 0.005%, Nb 0.055%, Ti 0.012%, Al 0.004%, Cr 1.95%, Mo 0.75%, Ni 2.65%, Cu 0.19%, W 0.008%, Zr 0.0004%, Ta 0.005%, rare earth La+Y0.0005%, La: Y mass Than being 2: 1, B 0.0005%, N 0.005%, surplus is Fe and inevitable impurity element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon flow amount is 0.15-0.2Nm3/min*/t-1, carbon contains Target≤0.04%, phosphorus content≤0.015% are measured, converter finishing slag basicity is 3.45-3.5, and tapping temperature is 1650-1670 DEG C； Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Comparative example 1
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C 0.01%, Si 0.15%, Mn 0.5%, P 0.001%, S 0.001%, Nb 0.025%, Ti 0.001%, Al 0.002%, Cr 1.85%, Mo 0.65%, Ni 2.55%, Cu 0.15%, W 0.005%, Zr 0.0001%, Ta 0.0001%, rare earth La+Y 0.0001%, La: Y mass ratio is 2: 1, B 0.0001%, N 0.0025%, and surplus is Fe and inevitable impurity element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon flow amount is 0.15-0.2Nm3/min*/t-1, carbon contains Target≤0.04%, phosphorus content≤0.015% are measured, converter finishing slag basicity is 3.45-3.5, and tapping temperature is 1650-1670 DEG C； Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/mm stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Comparative example 2
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C0.013%, Si 0.16%, Mn 0.86%, P 0.003%, S 0.002%, Nb 0.05%, Ti 0.011%, Al 0.003%, Cr 1.2%, Mo 0.2%, Ni 1.6%, Cu 0.1%, W 0.001%, Zr 0.0001%, rare earth La+Y 0.0002%, La: Y mass ratio are 2: 1, B 0.0003%, N 0.004%, surplus are Fe and inevitable impurity element.Process route includes：It is pre- to match stock → molten iron Processing desulfurization → converter smelting → LF refining → RH refinings → continuous casting → are rolled → are batched；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon flow amount is 0.15-0.2Nm3/min*t-1, carbon content Target≤0.04%, phosphorus content≤0.015%, converter finishing slag basicity are 3.45-3.5, and tapping temperature is 1650-1670 DEG C；It adopts With floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Comparative example 3
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C0.015%, Si 0.18%, Mn 0.88%, P 0.005%, S 0.005%, Nb 0.055%, Ti 0.012%, Al 0.004%, Cr 1.95%, Mo 0.75%, Ni 2.65%, Cu 0.19%, W 0.008%, Zr 0.0004%, Ta 0.005%, rare earth La+Y 0.0005%, La: Y mass ratio is 2: 1, B 0.0005%, N 0.002%, and surplus is Fe and inevitable impurity element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures liquid level thickness of slag layer≤15mm, oxygen blow duration 5-10min, oxygen supply intensity For 10000~13000m3/h, molten iron S content≤0.03% before handling, the granular magnesium and add that injection granularity is 1.2-1.5cm Enter pulverized limestone that granularity is 0.5-0.7mm to blast-melted desulfurization, the addition of magnesium is 0.1-0.2kg/t, the addition of pulverized limestone Amount is 7-8kg/t, Sulfur Content in Hot Iron content≤0.001% after processing；(2) converter smelting：Select 200t converters, selecting step (1) The molten iron of preparation and the steel scrap in other sources and slag, S content≤0.005%, C content≤0.07% in steel scrap, oxygen in slag Slugging content is 15-16wt%, molten iron: steel scrap: the mass ratio of slag is 15: 1: 1.2, first plus steel scrap, rear hot metal charging finally add Slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon Throughput is 0.15-0.2Nm3/min*/t-1, carbon content target≤0.04%, phosphorus content≤0.015%, converter finishing slag basicity is 3.45-3.5, tapping temperature are 1650-1670 DEG C；Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds 5-5.5kg/ The lime of t and the fluorite of 1.5-2kg/t make top slag；
(3) LF refining technique：The aluminium powder of 0.1-0.15kg/t, the fluorite of 0.1-0.15kg/t, 0.1-0.15kg/t is first added The lime of Fe-30Si powder, 0.1-0.15kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted after lime fusing in 300-350L/min Whole is 180-190L/min, stops being powered after the complete white slag of clinker, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800- 850L/min stirs 11-13min in this case, controls BOTTOM ARGON BLOWING flow later in 100-150L/min, stirs in this case 9-11min is mixed, is once again powered up adjustment bath temperature convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 680-700NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 30-40L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 10- 12min；4-5min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage open rolling temperature Degree is 770 DEG C, and the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
Comparative example 4
The low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C0.015%, Si 0.18%, Mn 0.88%, P 0.005%, S 0.005%, Nb 0.055%, Ti 0.012%, Al 0.004%, Cr 1.95%, Mo 0.75%, Ni 2.65%, Cu 0.19%, W 0.008%, Zr 0.0004%, Ta 0.005%, rare earth La+Y 0.0005%, La: Y mass ratio is 2: 1, B 0.0005%, N 0.005%, and surplus is Fe and inevitable impurity element.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches；It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: slag in slag Mass ratio is 15: 1: 1.2, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen Gas, early period, nitrogen intensity was 0.06-0.1Nm3/min*/t-1, later stage argon flow amount is 0.15-0.2Nm3/min*/t-1, carbon contains Target≤0.04%, phosphorus content≤0.015% are measured, converter finishing slag basicity is 3.45-3.5, and tapping temperature is 1650-1670 DEG C； Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/min 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1100 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1050 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1000 DEG C, and third reduction in pass is 8-9mm, and four-pass start rolling temperature is 930 DEG C, and four-pass drafts is 6- 7mm；Second stage rolls for austenite Unhydrated cement, and specifically the first passage start rolling temperature is 830 DEG C, the pressure of the first passage Amount is 3-5mm, and the second passage start rolling temperature is 770 DEG C, and the second reduction in pass is 2-3mm；(6) it cools down and batches；Steel plate into Enter section cooling region, is cooled to 530~550 DEG C with the cooling velocity of 10-14 DEG C/s, batches later.
Mechanical properties test, field trash type, size inspection are carried out to the steel plate of the embodiment of the present invention 1~3 and comparative example 1-4 It surveys, inspection result is shown in Table 1-2.
Table 1
Type Yield strength (MPa) Tensile strength (MPa) - 40 DEG C of impact flexibility (J) Elongation percentage (%)
Embodiment 1 ≥730 ≥850 ≥110 ≥20.1
Embodiment 2 ≥780 ≥900 ≥120 ≥18.8
Embodiment 3 ≥810 ≥930 ≥130 ≥17.2
Comparative example 1 ≥525 ≥663 ≥88 ≥13.5
Comparative example 2 ≥580 ≥731 ≥102 ≥12.7
Comparative example 3 ≥601 ≥748 ≥114 ≥14.3
Comparative example 4 ≥630 ≥742 ≥122 ≥11.8
Table 2
Term used herein is explanation and term exemplary, and not restrictive.Since the present invention can be with a variety of Form be embodied without departing from invention spirit or essence, it should therefore be appreciated that above-described embodiment be not limited to it is any above-mentioned Details, and should widely being explained in the spirit and scope defined by appended claims, thus fall into claim or its etc. Whole variations and remodeling in effect range all should be appended claims and covered.

Claims (6)

1. a kind of low production method for being mingled with clean steel, it is characterised in that：Composition of steel is C 0.012-0.015%, Si 0.15- 0.18%, Mn 0.85-0.88%, P≤0.005%, S≤0.005%, Nb 0.045-0.055%, Ti 0.010- 0.012%, Al≤0.005%, Cr 1.85-1.95%, Mo 0.65-0.75%, Ni 2.55-2.65%, Cu 0.15- 0.19%, W 0.005-0.008%, Zr 0.0001-0.0004%, Ta 0.0001-0.005%, rare earth La+Y 0.0001- 0.0005%, La: Y mass ratio is 2: 1, B 0.0001-0.0005%, N 0.001-0.005%, N/Al 1.2-1.4, surplus For Fe and inevitable impurity element, the Carbonitride Precipitation object of Nb, Ti, Mo are formd, Nb: Ti: Mo is former in the precipitate For son than being 4: 1: 0.2, precipitate grain size is 40-60nm, the bainite that final tissue is 97% or more with area occupation ratio statistics, iron element Body, pearlite area occupation ratio are 3% hereinafter, 2-5 μm of average grain size；Yield strength is 730-810MPa, and tensile strength is 850-930MPa, -40 DEG C of impact flexibility are 110-130J, elongation percentage 17-20%.
Process route includes：Proportioning stock → molten iron pretreatment desulfurizing → converter smelting → LF refining → RH refinings → continuous casting → are rolled It makes → batches.It is as follows：
(1) KR molten iron pretreatment desulfurizings：It pulls out slag and ensures that liquid level thickness of slag layer≤15mm, oxygen blow duration are 14~18min, oxygen supply is strong Degree is 10000~13000m3/h, molten iron S content≤0.03% before handling, granular magnesium that injection granularity is 1.2-1.5cm and The pulverized limestone that addition granularity is 0.5-0.7mm is to blast-melted desulfurization, and the addition of magnesium is 0.2-0.3kg/t, and pulverized limestone adds It is 10-11kg/t, Sulfur Content in Hot Iron content≤0.001% after processing to enter amount；
(2) converter smelting：Select 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), steel scrap Middle S content≤0.005%, C content≤0.07%, oxidizing slag content is 15-16wt%, molten iron: steel scrap: the matter of slag in slag It is 15: 1: 1.2 to measure ratio, and first plus steel scrap, rear hot metal charging finally add slag, using double slag operation, bottom-blowing of converter argon gas and nitrogen, Early period, nitrogen intensity was 0.06-0.1Nm3/min*t-1, later stage argon flow amount is 0.15-0.2Nm3/min*t-1, carbon content target ≤ 0.04%, phosphorus content≤0.015%, converter finishing slag basicity is 3.45-3.5, and tapping temperature is 1650-1670 DEG C；Using gear The double slag-stopping tappings of slag plug, scum rod；Tapping process adds the lime of 5-5.5kg/t and the fluorite of 1.5-2kg/t to make top slag；
(3) LF refining technique：The Fe- of the aluminium powder of 0.2-0.25kg/t, the fluorite of 0.2-0.3kg/t, 0.2-0.3kg/t is first added The lime of 30Si powder, 1-2kg/t first controls BOTTOM ARGON BLOWING flow and is adjusted to 180- after lime fusing in 500-550L/mm 190L/min stops after the complete white slag of clinker being powered, makes white slag target component：CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow is in 800-850L/min, in this shape 11-13min is stirred under state, is controlled BOTTOM ARGON BLOWING flow later in 100-150L/min, is stirred 9-11min in this case, again Adjustment bath temperature be powered convenient for tapping, soft blow stops Argon, terminates LF refining；
RH is refined：It is vacuumized under the conditions of not oxygen blown and carries out nature decarburization, promote Ar flow 880-900NL/min, carry out steel Water dehydrogenation ensures depth vacuum processing time >=15min, and the Al-Mg-Mn double deoxidizer removing molten steel of 0.04-0.05kg/t is added In extra oxygen, alloying then is carried out to molten steel with low-carbon ferromanganese, ferrosilicon and ultralow carbon alloy, last batch of alloy has adjusted At later, it is desirable that vacuum processing time 6-7min, during which thermometric, sampling, fine tuning composition；Vacuum terminates to carry out determining hydrogen；Per stove Molten steel feeds SiCa lines, and ensures that Ca contents are between 25~30ppm in molten steel, is adjusted according to calcium content in steel；It is right before bull ladle Molten steel carries out soft blow, and soft blow argon flow amount is controlled in 50-60L/min, and the top of the slag is not blown open, ensures molten steel soft blow time 14- 15min；8-9min is stood after soft blow；
(4) continuous casting process：Whole blowing argon avoids molten steel oxidation, controls casting process nitrogen pick-up；Covering agent avoids in Molten steel is exposed, and secondary cooling water matches aqueous mode according to low-carbon alloy steel, selects low-carbon alloy covering slag, obtains the plate that thickness is 50mm Base；
(5) it heats and rolls；The slab that thickness is 50mm is put into heating furnace, 1180~1185 DEG C of heating temperature, heating time 50-60min, first stage roll for austenite recrystallization area, and specifically the first passage start rolling temperature is 1120 DEG C, the first passage Drafts is 10-11mm, and the second passage start rolling temperature is 1070 DEG C, and the second reduction in pass is 9-10mm, third passage open rolling Temperature is 1030 DEG C, and third reduction in pass is 7-8mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5- 6mm, the 5th passage start rolling temperature are 870 DEG C, and the 5th reduction in pass is 3-4mm；Second stage is austenite Unhydrated cement Rolling, specifically the first passage start rolling temperature are 820 DEG C, and the first reduction in pass is 2.5-3.5mm, the second passage start rolling temperature It it is 770 DEG C, the second reduction in pass is 1-2mm；
(6) it cools down and batches；Steel plate enters section cooling region, and 530~550 are cooled to the cooling velocity of 15~25 DEG C/s DEG C, it batches later.
2. the low production method for being mingled with clean steel as described in claim 1, it is characterised in that：Composition of steel is C 0.012%, Si 0.15%, Mn 0.85%, P 0.001%, S 0.001%, Nb 0.045%, Ti 0.01%, Al 0.002%, Cr 1.85%, Mo 0.65%, Ni 2.55%, Cu 0.15%, W 0.005%, Zr 0.0001%, Ta 0.0001%, rare earth La + Y 0.0001%, La: Y mass ratio are 2: 1, B 0.0001%, N 0.0025%, and surplus is Fe and inevitable impurity member Element.
3. the low production method for being mingled with clean steel as claimed in claim 2, it is characterised in that：Composition of steel is C0.015%, Si 0.18%, Mn 0.88%, P 0.005%, S 0.005%, Nb 0.055%, Ti 0.012%, Al 0.004%, Cr 1.95%, Mo 0.75%, Ni 2.65%, Cu 0.19%, W 0.008%, Zr 0.0004%, Ta 0.005%, rare earth La+ Y 0.0005%, La: Y mass ratio are 2: 1, B 0.0005%, N 0.005%, and surplus is Fe and inevitable impurity element.
4. the low production method for being mingled with clean steel as described in claim 1, it is characterised in that：Step (2) converter smelting：It selects 200t converters, the steel scrap and slag of molten iron and other sources prepared by selecting step (1), S content≤0.005%, C contain in steel scrap ≤ 0.07% is measured, oxidizing slag content is 15.5wt%, molten iron: steel scrap: the mass ratio of slag is 15: 1: 1.2 first plus gives up in slag Steel, rear hot metal charging finally add slag, and using double slag operation, bottom-blowing of converter argon gas and nitrogen, early period, nitrogen intensity was 0.08Nm3/ min*t-1, later stage argon flow amount is 0.18Nm3/min*t-1, carbon content target≤0.04%, phosphorus content≤0.015%, converter Finishing slag basicity is 3.48, and tapping temperature is 1660 DEG C；Using floating plug, the double slag-stopping tappings of scum rod；Tapping process adds 5.3kg/t Lime and the fluorite of 1.8kg/t make top slag.
5. the low production method for being mingled with clean steel as described in claim 1, it is characterised in that：0.23kg/t is first added in step (3) Aluminium powder, the fluorite of 0.25kg/t, the Fe-30Si powder of 0.25kg/t, 1.5kg/t lime, first control BOTTOM ARGON BLOWING flow exist 530L/min is adjusted to 185L/min after lime fusing, stops being powered after the complete white slag of clinker, makes white slag target component： CaO 55%, SiO2 27%, Al2O3 12%, MgO 5%, FeO+Fe2O3+MnO≤1.0%；Stirring desulphurization energetically, control BOTTOM ARGON BLOWING flow stirs 12min in this case in 830L/min, controls BOTTOM ARGON BLOWING flow later in 130L/min, in this shape 10min is stirred under state, is once again powered up adjustment bath temperature convenient for tapping, soft blow stops Argon, terminates LF refining.
6. the low production method for being mingled with clean steel as described in claim 1, it is characterised in that：Step (5) heats and rolling；It will be thick The slab that degree is 50mm puts into heating furnace, and 1180~1185 DEG C of heating temperature, heating time 50-60min, the first stage is Ovshinsky Body recrystallization zone rolls, and specifically the first passage start rolling temperature is 1120 DEG C, and the first reduction in pass is 10.5mm, the second passage Start rolling temperature is 1070 DEG C, and the second reduction in pass is 9.5mm, and third passage start rolling temperature is 1030 DEG C, the pressure of third passage Amount is 7.5mm, and four-pass start rolling temperature is 940 DEG C, and four-pass drafts is 5.5mm, and the 5th passage start rolling temperature is 870 DEG C, the 5th reduction in pass is 3.5mm；Second stage is chamber body Unhydrated cement rolling difficult to understand, specifically the first passage open rolling temperature Degree is 820 DEG C, and the first reduction in pass is 3mm, and the second passage start rolling temperature is 770 DEG C, and the second reduction in pass is 1.5mm.
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CN110982979A (en) * 2019-12-30 2020-04-10 首钢集团有限公司 Production method of ultra-low carbon steel for iron-based alloy
CN112474792A (en) * 2020-10-26 2021-03-12 邯郸钢铁集团有限责任公司 Cogging rolling production method for industrial pure iron
CN114959428A (en) * 2022-05-24 2022-08-30 武汉科技大学 Steel making method of free-cutting non-quenched and tempered steel and non-quenched and tempered steel
CN115667565A (en) * 2020-03-31 2023-01-31 日本制铁株式会社 Steel material

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CN115667565B (en) * 2020-03-31 2023-08-29 日本制铁株式会社 Steel material
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CN114959428B (en) * 2022-05-24 2023-08-11 武汉科技大学 Steelmaking method of free-cutting non-quenched and tempered steel and non-quenched and tempered steel

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