CN108559917A - A kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates and its manufacturing method - Google Patents
A kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates and its manufacturing method Download PDFInfo
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- 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
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- 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
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- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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- 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
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- 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
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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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- 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
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
Abstract
The invention discloses a kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates, are related to field of steel metallurgy, and chemical composition and weight percent are as follows：C：0.15~0.22%, Si：0.10~0.30%, Mn：0.80~1.60%, Cr：0.20~0.70%, Mo：0.10~0.60%, Nb：0.020~0.050%, V：0.020~0.060%, Ti≤0.008%, B：0.0010~0.0030%, Al：0.02~0.06%, P≤0.005%, S≤0.002%, O≤0.0025%, N≤0.0040%, H≤0.00015%, surplus are Fe and inevitable impurity, carbon equivalent Ceq=C+Mn/6+（Cr+Mo+V）/5+Ni/15≤0.55%.Present component economy, it is simple for process, make steel plate that there is excellent comprehensive mechanical property using Grain Refinement Effect, generates good economic benefit and social benefit.
Description
Technical field
The present invention relates to field of steel metallurgy, more particularly to a kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates
And its manufacturing method.
Background technology
In recent years, due to being constrained by environmental issue, energy problem and cost problem, machinery etc. in engineering machinery and mine
Industry develops towards enlargement and light-weighted direction, it is desirable that engineering machinery will not reduce even mitigating the while of conducting oneself with dignity
Improve load-carrying ability, it is therefore desirable to the structural steel and iron of the more higher levels of application.High strength structure plate mainly for the manufacture of rise
The arm of heavy-duty machine, the structural members such as the crossbeam of engineering machinery and the car body of dumper.The annual crane total output in China is 1000
Ten thousand tons or so, and boom weight accounts for the 15-20% of exchange weight, the structural steel and iron consumed every year is at 1,500,000 tons or so.This
Before, domestic each steel mill to produce based on the steel plates of the following ranks of yield strength 960MPa, the structural steel and iron of higher level mainly according to
By import.
High strength structure plate has very strict want due to its harsh use environment and stress condition to steel product quality
It asks.It produces difficult point and is：(1) superhigh intensity obtains good plasticity and toughness simultaneously.Normal conditions, armor plate strength increase, and modeling is tough
Property reduce, how to improve intensity simultaneously and plasticity and toughness be the key point for manufacturing high-tensile structural steel.(2) how Thin Specs to be controlled
The template of steel plate.Due to the superposition of structural stress and thermal stress in quenching process, it is easy that steel plate edge and center portion is made to generate
Wave cannot be satisfied template requirement.(3) effective full hardening deepness of thick steel plates how is improved.Steel plate is thicker, surface and center portion
Quenching effect gap increases, and it is uneven to be easy to cause steel plate thickness direction performance.(4) how to improve steel plate welding performance.Structure
Part improves intensity meeting typically by bending and welding fabrication, and under normal conditions by increasing the content of C and alloying element
It is significant to deteriorate welding sexual function.(5) how to improve steel plate cold bending performance.Under normal conditions, armor plate strength is higher, plastic deformation
Ability is poorer, it is difficult to meet the bending demand of structural member.(6) lower production cost how is obtained.By adding a large amount of close
Gold element can improve intensity and plasticity, but excessively high production cost is that enterprise is unacceptable.Therefore it must be set from tissue
The Strengthening and Toughening requirement of steel plate is realized on meter and technology controlling and process.
Currently, the domestic enterprise that can supply yield strength 1100MPa grade high-strength structural steel and irons in batches not yet, mainly
By import.Chinese patent CN102747303B describes a kind of yield strength 1100MPa grades of high strength steel plates and its manufacturing method,
The invention improves the toughness of steel by the Ni of addition 0.60~2.00%, and the price of Ni is very expensive, increases production cost.
Chinese patent CN104513936A discloses a kind of yield strength 1100MPa grades of quenching and tempering, highs and its production method, equally adds
0.30~1.50% Ni is added, and a certain amount of Ti and Ca of addition tough come the modeling for reducing N and S by controlling Ti/N and Ca/S
Property harm, to realize the obdurability matching of high-strength steel, composition design is more complex.Chinese patent CN100372962C is described
A kind of method of press quenching+tempering produces the ultrahigh-strength steel plates of yield strength 1100MPa or more, by addition 0.20~
1.20% and 0~0.5% Cu improves toughness, in addition, the steel plate of press quenching is without reheating austenitizing, in steel plate
Stress is larger, easy tos produce crackle in follow-up cutting and Cold Bending, there are certain limitations for practical application.Chinese patent
CN106191673A describes a kind of steel plate and preparation method thereof of the cold-bending property excellent yield strength more than 1100MPa, passes through
Straightening process reduces the central defect of steel plate to control template and the dynamic soft-reduction technique of steel plate twice, and complex process pair is set
Standby is more demanding, does not utilize the popularization and application of the technology.
In conclusion the existing manufacturing technology for being related to 1100MPa grades of ultra-high strength steel plates of yield strength at present mainly has：(1)
Improve the toughness of super-high strength steel by adding a large amount of precious metal Ni or Ni+Cu, economy is poor；(2) by adding Ti
With Ca control Ti/N and Ca/S improves plasticity and toughness to reduce N and S, and composition design is complicated；(3) it is returned by press quenching and low temperature
The mode of fire obtains martensite superhigh intensity.(4) super-high strength steel is controlled by the cold strong straightening process twice of temperature correction and strength
Template, technique are loaded to the more demanding of equipment.
Invention content
The present invention in view of the above technical problems, the shortcomings that overcoming the prior art, provide a kind of yield strength 1100MPa grades it is super
Fine grain high strength steel plate reduces the content of alloying element by simple Design of Chemical Composition, so that iron and steel enterprise is easy to implement
Technique, while there is superhigh intensity and good low-temperature toughness and plastic deformation ability.
In order to solve the above technical problems, the present invention provides a kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates,
Chemical composition and weight percent are as follows：C：0.15~0.22%, Si：0.10~0.30%, Mn：0.80~1.60%, Cr：
0.20~0.70%, Mo：0.10~0.60%, Nb：0.020~0.050%, V：0.020~0.060%, Ti≤0.008%,
B：0.0010~0.0030%, Al：0.02~0.06%, P≤0.005%, S≤0.002%, O≤0.0025%, N≤
0.0040%, H≤0.00015%, surplus are Fe and inevitable impurity, and carbon equivalent Ceq=C+Mn/6+ (Cr+Mo+V)/
5+Ni/15≤0.55%.
Technique effect：The present invention reduces a large amount of alloying elements, are not added with the precious metal elements such as Ni, Cu, have saved life
Produce cost；Carbon equivalent Ceq is reduced to 0.55% hereinafter, improving the welding performance of steel plate；The yield strength of steel plate >=
1100MPa has good obdurability and plastic deformation ability, especially under conditions of being not added with Ni, has extraordinary
Low-temperature flexibility.
The technical solution that the present invention further limits is：
Further, the thickness of steel plate is 5~30mm.
Another object of the present invention is to provide a kind of manufacturers of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates
Method includes the following steps：
It smelts：By above-mentioned chemical composition use electric furnace or converter smelting, by LF stoves refine, most afterwards through VD or RH vacuum outgas at
Reason；
Continuous casting：Design liquidus temperature be 1510 DEG C, pouring temperature be 1515~1530 DEG C, strand it is offline after enter holding pit or
Heap, which more than cold 24 hours carries out expanding hydrogen, in capping insulation cover is handled；
Heating：By heating strand to 1150~1200 DEG C, start to keep the temperature after strand center portion temperature to temperature, heat preservation duration 1~
1.5mim/mm；
Rolling：Using two benches controlled rolling process, strand first enters recrystallization zone roughing, roughing after coming out of the stove after high pressure water dephosphorization
1100~1150 DEG C of start rolling temperature, reduction ratio >=20% of three passages after roughing, roughing steel plate wait for that temperature thickness >=2.2H, H are steel
The final rolling thickness of plate；Finish rolling start rolling temperature is 850~950 DEG C, finish rolling stage total reduction >=70%, percentage pass reduction >=
15%, and increase drafts in Unhydrated cement；
It is cooling：Steel plate is air-cooled to room temperature again after being cooled to 600 DEG C with the cooling velocity of 30 DEG C/s or more after rolling；
Quenching：It is 814 DEG C that the austenite of steel, which starts phase transition temperature Ac3, is quickly heated up to the heating speed of 50 DEG C/min or more
840~860 DEG C, a length of 1~1.5min/mm when keeping the temperature after furnace temperature to temperature utilizes the quick water cooling of quenching press heat treatment equipment to room
Temperature；
Tempering：Quenched steel plate is heated to 200~240 DEG C, a length of 2~3min/mm, is air-cooled to when being kept the temperature after furnace temperature to temperature
Room temperature.
A kind of manufacturing method of preceding yield strength 1100MPa grade Ultra-fine Grained high strength steel plates, in casting process, whole process
Using argon for protecting pouring.
A kind of manufacturing method of preceding yield strength 1100MPa grade Ultra-fine Grained high strength steel plates, in casting process, use
Electromagnetic agitation, stirring parameter 320A, 6Hz.
Technique effect：Above-mentioned technique provided by the invention is by rational designing chemical composition and combines rolling, cooling technique
With heat treatment process control measure, develops yield strength and be more than 1100MPa, while there is good plasticity and low-temperature flexibility
Ultra-fine Grained high-strength steel sheet；Crystal grain thinning is uniquely can not only to have improved intensity but also can improve the schedule of reinforcement of plasticity and toughness, this hair
The bright toughness reguirements that steel plate is realized by crystal grain thinning reduces the addition of the alloying elements such as Ni, Mn, Cr, on the one hand drops
The low carbon equivalent of steel plate, improves welding performance, has on the other hand saved cost, improve the competitiveness of product.
Compared with prior art, the beneficial effects of the invention are as follows：
(1) ultrafast cold measure after rolling and roll by two-stage control in the present invention, refines the precipitation particles size of (Nb, V) C
To 10mm hereinafter, its intergranular precipitation is made to be precipitated, its pinning crystal boundary is significantly improved, the effect that prevention crystal grain is grown up；
(2) increase austenite crystal interfacial area, Reducing distortion austenite by increasing non-recrystallization zone rolling reduction in the present invention
Width, it is thin to play to increase the nucleation site and the resistance of austenite grain cross growth that reheat austenite
Change the effect of austenite grain；
(3) steel plate is heated to hardening heat using rapid heating process in the present invention, and according to austenite phase transformation start temperature,
Hardening heat is reduced to 840~860 DEG C, avoids growing up for austenite grain, is less than 10 μm to obtain average grain size
Austenite grain；
(4) 200~240 DEG C of lonneals are used in the present invention, eliminate quenching internal stress, and remain high dislocation density
Lath martensite, to obtain good obdurability；
(5) microscopic structure of Ultra-fine Grained high strength steel plate is the tempering lath martensite of high dislocation density, prior austenite in the present invention
10 μm of body crystallite dimension ＜, micro- grain size number reach 11 grades, and mechanical property of steel plate meets：Tensile strength >=1250MPa, prolongs
Stretch rate >=12%, low temperature Charpy-V impact power >=60J, unevenness≤3mm/m at -40 DEG C, and there is good clod wash and welding
Performance.
Description of the drawings
Fig. 1 is the optics microstructure morphology photo (500 ×) of 1 light plate of embodiment；
Fig. 2 is the scanning electron microscope microstructure morphology photo (500 ×) of 2 light plate of embodiment；
Fig. 3 is that 3 light plate of embodiment rolls the precipitation particles appearance and size after rear ultra-rapid cooling；
Fig. 4 is the micro- crystallite dimension photo (200 ×) of 3 light plate of embodiment；
Fig. 5 is the micro- crystallite dimension photo (200 ×) of 4 light plate of embodiment.
Specific implementation mode
A kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates provided in this embodiment, chemical composition and weight hundred
Divide ratio as follows：C：0.15~0.22%, Si：0.10~0.30%, Mn：0.80~1.60%, Cr：0.20~0.70%, Mo：
0.10~0.60%, Nb：0.020~0.050%, V：0.020~0.060%, Ti≤0.008%, B：0.0010~
0.0030%, Al：0.02~0.06%, P≤0.005%, S≤0.002%, O≤0.0025%, N≤0.0040%, H≤
0.00015%, surplus is Fe and inevitable impurity, and carbon equivalent Ceq=C+Mn/6+ (Cr+Mo+V)/5+Ni/15≤
0.55%.
Design of Chemical Composition principle in the present invention：
C：The content of C directly determines the intensity rank and welding performance of steel plate.C is solid-solution in the octahedron or four of ferrite lattice
In the body space of face, serious lattice distortion is caused, and reciprocation, the strong movement for hindering dislocation, to propose occurs with dislocation
High intensity.But C content is excessively high, lattice distortion degree is bigger, and shear drag increases, and significantly reduces the plasticity and toughness of steel, exists in addition
In welding process, heat affected area easy tos produce cold crack, reduces the performance of welding point, therefore in the present invention, C content is controlled
0.15~0.22%.
Si：The Fe atoms in ferrite crystal lattice are mainly substituted with substitute mode in steel, play the work of solution strengthening
With.In addition, Si can reduce the diffusivity of C atoms, the formation of carbide in drawing process is prevented, to improve steel belt roof bolt
Drag.It but when Si too high levels, can significantly deteriorate the surface quality of steel plate, therefore Si contents are controlled 0.10~0.30%.
Mn：Mn can inhibit diffusion transformation process, improve the quenching degree of steel, can also reduce the harm of steel grade S, this
Outside, moreover it is possible to play solution strengthening effect.But when Mn too high levels, it is be easy to cause the center segregation of strand, deteriorates group inside steel plate
It knits, reduces the toughness and welding performance of steel plate, therefore Mn contents are controlled 0.80~1.60%.
Cr：Solution strengthening element can inhibit the formation of polygonal ferrite and pearlite, promote bainite and martensite
Transformation, to improve intensity.But when Cr too high levels, being easy to be formed the carbide of Cr reduces the toughness of steel plate and is unfavorable for steel
The welding performance of plate, therefore Cr contents are controlled 0.20~0.70%.
Ni：Quenching degree element is improved, and can directly improve the toughness of steel, belongs to precious metal, it is expensive,
It is added without the element in the present invention, reduces production cost, improves the competitiveness of steel grade.
Mo：Quenching degree element is improved, the formation of martensite in quenching process is promoted.In addition, Mo can also play refinement crystalline substance
Grain effect is conducive to the martensitic structure refined, but Mo too high levels can deteriorate the welding performance of steel, therefore the present invention
It is middle to control Mo contents 0.10~0.45%, to obtain the matching of steel plate obdurability and welding performance.
Nb：In the present invention, the effect of Nb is most important.The simple substance atom of Nb and the carbide of Nb can significant pinnings
Austenite grain boundary prevents crystal grain from growing up.In addition, the recrystallization temperature of austenite can be improved in the solute effect of dragging of Nb, be conducive to
The non-recrystallization zone rolling for realizing austenite, improves dislocation density, the reheating austenite grain to be refined provides item
Part.
V：V is carbide, these nano level V (C, N) Dispersed precipitates can play in the matrix of steel
The effect of precipitation strength improves the intensity of steel plate.In addition, during heating austenite grain can be prevented with pinning crystal boundary
It grows up, plays the role of crystal grain thinning.But when V content is excessively high, becoming large-sized for precipitation particles is unfavorable to toughness instead, therefore
The content of V is controlled 0.020~0.060%.
Ti：Ti and C, N have extremely strong affinity.Ti and N is easy to form coarse TiN during solidification of molten steel, and TiN is hard
And it is crisp, be unlikely to deform, cause during rolling deformation with matrix can not cooperative transformation, to generate micro-crack, significantly
The toughness and cold-bending property of steel are reduced, therefore does not allow that Ti elements are added in the present invention.
B：Most effective raising quenching degree element, the martensitic structure for promoting steel plate to be refined in cooling procedure, from
And improve intensity.But when B content is excessively high, it can be enriched in grain boundaries, reduce the combination energy of crystal boundary, to reduce the toughness of steel plate,
Therefore B content is controlled 0.0010~0.0030%.
Al：On the one hand Al plays deoxidation in steel, purify Cleanliness of Molten Steel；On the other hand it is also used in fixed steel
N, avoid the formation of the toughness that coarse TiN deteriorates steel；It can also play the role of protecting B, avoid BN in the precipitation of crystal boundary, from
And ensures B and improve the effect of quenching degree.In addition, tiny AlN may also suppress austenite grain in subsequent cooling procedure
It grows up, plays the role of crystal grain thinning, therefore Al content is controlled 0.02~0.06%.
N：Pernicious gas element forms the toughness that hard crisp TiN significantly deteriorates steel with Ti, and BN is formed in grain boundaries richness with B
Collection, reduce crystal boundary combine can, with Al formed AlN can fining austenite grains, refined crystalline strengthening can be played the role of, therefore by N
Content is controlled≤0.0040%
P：P can reduce the combination energy of crystal boundary in grain boundaries segregation, in the case where impacting outer force effect, be easy to happen intergranular brittle fracture,
It is the main reason for causing one-step temper embrittlement.In the presence of P and Mn are common, steel belt roof bolt brittleness can be aggravated, significantly deteriorate steel
The toughness of plate.In addition, P can also deteriorate the welding performance of steel, therefore content≤0.005% of stringent control P.
S：During solidification of molten steel, segregation can occur for S, form sulphide inculsion, reduce the low-temperature flexibility of steel plate and cold
Curved performance.In welding process, the formation of sulfide is also easy to generate fire check, and S occurs the SO2 gases that oxidation is formed and welding
Stomata is easy tod produce in seam metal, reduces the performance of welding point, therefore content≤0.002% of stringent control S.
O：Pernicious gas element, content is high, and the field trash of generation is more, reduces the moulding of steel plate, toughness and cold-bending property, sternly
Lattice control O content≤0.0025%.
H：Pernicious gas element, H atom are easy fault aggregation in place in steel, cause local H partial pressures excessively high, form fine fisssure
Line is crisp to generate H, reduces steel plate plasticity and toughness, seriously endangers the performance of steel plate.In addition, H content is excessively high or superelevation is strong
Steel plate forms the main reason for cutting delayed crack, therefore content≤0.00015% of stringent control H.
The present invention the technological process of production be：Converter or electric furnace steel making → LF stoves refining → VD or RH Fruit storages →
Continuous casting → strand expands hydrogen processing → heating → rolling → cooling → quenching → tempering.Core of the invention is through fine
Crystal grain realizes obdurability and the plastic deformation ability requirement of unimach, therefore in each stage for rolling and being heat-treated
Run through the measure of crystal grain thinning, concrete technology flow process is as follows：It smelts：150 tons of converters or electric furnace are used by above-mentioned chemical composition
It smelts, is refined by LF stoves, most afterwards through VD or RH Fruit storages.
Continuous casting：The molten steel of smelting is cast into the strand of 150~220mm, the liquidus curve of tapping is calculated according to chemical composition
Temperature is 1510 DEG C, and pouring temperature is that liquidus temperature adds 5~20 DEG C i.e. 1515~1530 DEG C, and casting speed control is in 1~1.35m/
Min, to prevent molten steel oxidation, whole argon for protecting pouring from being used in casting process to mitigate strand center porosity and segregation
Electromagnetic agitation, stirring parameter 320A, 6Hz；Enter cold 24 hours of heap in holding pit or capping insulation cover after strand is offline
It carries out expanding hydrogen processing above.
Heating：Continuous casting billet is fitted into walking beam furnace, is heated to 1150~1200 DEG C, waits for strand center portion temperature to temperature
After start to keep the temperature, keep the temperature 1~1.5mim/mm of duration, so that the chemical composition in austenite is homogenized.
Rolling：Using two benches controlled rolling process, strand first enters recrystallization zone roughing after coming out of the stove after high pressure water dephosphorization,
1100~1150 DEG C of roughing start rolling temperature, reduction ratio >=20% of three passages after roughing make the abundant recrystallization softening of austenite, keep away
Exempt from abnormal coarse crystal grain occur, roughing steel plate waits for that temperature thickness >=2.2H, H are the final rolling thickness of steel plate；Finish rolling start rolling temperature
It is 850~950 DEG C, finish rolling stage total reduction >=70%, percentage pass reduction >=15%, and depressed in Unhydrated cement increase
Amount, makes austenite grain elongate, and fully increases the grain boundary area of austenite, reduces the width of austenite grain.
It is cooling：Online ultra-rapid cooling is carried out to the steel plate after rolling, 600 are cooled to the cooling velocity of 30 DEG C/s or more
Room temperature is air-cooled to after DEG C again, quickly through ferrite transformation region, inhibits precipitations of (the Nb, V) C in high temperature ferrite, makes it
In subsequent cooling procedure in a manner of homogeneous nucleation Precipitation, at this time be precipitated driving force it is big, critical nuclei size is small, analysis
It is slow to go out particle growth speed, size can be obtained in 10mm (Nb, V) C below, notable pinning can be played and reheat austenite border
Boundary, the effect for preventing crystal grain from growing up.
Quenching：It is 814 DEG C to start phase transition temperature Ac3 according to the austenite of plavini measurement steel, and Austria is reheated in order to refine
Family name's body crystal grain will roll steel plate after cooling and quickly heat up to 840~860 DEG C with the heating speed of 50 DEG C/min or more, furnace temperature
A length of 1~1.5min/mm, utilizes the quick water cooling of quenching press heat treatment equipment to room temperature when being kept the temperature after to temperature.
Tempering：Quenched steel plate is heated to 200~240 DEG C, a length of 2~3min/mm, empty when being kept the temperature after furnace temperature to temperature
It is cooled to room temperature, eliminates the quenching internal stress of steel plate.
By chemical composition shown in table 1, the Ultra-fine Grained high-strength steel sheet in 1~embodiment of embodiment 4 is manufactured.It will heat treatment
Steel plate afterwards carries out cross directional stretch, impact of collision experiment.Specific ingredient and technological parameter in 1~embodiment of embodiment 4 are shown in Table 1
The properties of~table 3, steel plate obtained are shown in Table 4.
The chemical composition (wt%) of Ultra-fine Grained high-strength steel sheet in 1 1~embodiment of embodiment 4 of table
The rolling cooling technique control of Ultra-fine Grained high-strength steel sheet in 2 1~embodiment of embodiment 4 of table
The heat treatment process control of Ultra-fine Grained high-strength steel sheet in 3 1~embodiment of embodiment 4 of table
| Embodiment | Thickness/mm | Heating speed DEG C/s | Heating temperature/DEG C | Quenching Soaking Time/min | Temperature/DEG C | Tempering insulation time/DEG C |
| 1 | 6 | 5 | 840 | 10 | 200 | 20 |
| 2 | 8 | 5 | 840 | 15 | 210 | 25 |
| 3 | 20 | 5 | 850 | 25 | 220 | 50 |
| 4 | 30 | 5 | 860 | 30 | 230 | 75 |
The stretching of Ultra-fine Grained high-strength steel sheet, impact property in 4 1~embodiment of embodiment 4 of table
Note：When steel plate thickness is 6mm and 8mm, half impact style is taken by requirements of the national standard.
As shown in Figs. 1-2, the microstructure of steel is tempering lath martensitic structure, and as in Figure 3-5, original austenite is flat
Equal crystallite dimension is less than 10 μm.Mechanical property of steel plate meets：Tensile strength >=1250MPa, elongation percentage >=12%, -40 DEG C of whens, are low
Warm Charpy-V impact power >=60J, unevenness≤3mm/m, and there is good clod wash and welding performance.The present invention is ultra-fine from organizing
The angle of change, by optimizing composition design, controlled rolling and Controlled cooling process and control heat treatment process, eventually by thin
The lath martensite tissue of change ensures plasticity and toughness while realizing armor plate strength.Steel plate produced by the invention has been successfully applied to
On the equipment of Machinery Enterprises, instead of import, good economic benefit and social benefit are produced.
In addition to the implementation, the present invention can also have other embodiment.It is all to use equivalent substitution or equivalent transformation shape
At technical solution, fall within the scope of protection required by the present invention.
Claims (5)
1. a kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates, which is characterized in that its chemical composition and weight percent are such as
Under：C：0.15~0.22%, Si：0.10~0.30%, Mn：0.80~1.60%, Cr：0.20~0.70%, Mo：0.10~
0.60%, Nb：0.020~0.050%, V：0.020~0.060%, Ti≤0.008%, B：0.0010~0.0030%, Al：
0.02~0.06%, P≤0.005%, S≤0.002%, O≤0.0025%, N≤0.0040%, H≤0.00015%, surplus
For Fe and inevitable impurity, and carbon equivalent Ceq=C+Mn/6+（Cr+Mo+V）/5+Ni/15≤0.55%.
2. a kind of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates according to claim 1, it is characterised in that：Steel plate
Thickness be 5~30mm.
3. a kind of manufacturing method of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates as described in claim 1~2, special
Sign is, includes the following steps：
It smelts：By above-mentioned chemical composition use electric furnace or converter smelting, by LF stoves refine, most afterwards through VD or RH vacuum outgas at
Reason；
Continuous casting：Design liquidus temperature be 1510 DEG C, pouring temperature be 1515~1530 DEG C, strand it is offline after enter holding pit or
Heap, which more than cold 24 hours carries out expanding hydrogen, in capping insulation cover is handled；
Heating：By heating strand to 1150~1200 DEG C, start to keep the temperature after strand center portion temperature to temperature, heat preservation duration 1~
1.5mim/mm；
Rolling：Using two benches controlled rolling process, strand first enters recrystallization zone roughing, roughing after coming out of the stove after high pressure water dephosphorization
1100~1150 DEG C of start rolling temperature, reduction ratio >=20% of three passages after roughing, roughing steel plate wait for that temperature thickness >=2.2H, H are steel plate
Final rolling thickness；Finish rolling start rolling temperature is 850~950 DEG C, finish rolling stage total reduction >=70%, percentage pass reduction >=15%,
And increase drafts in Unhydrated cement；
It is cooling：Steel plate is air-cooled to room temperature again after being cooled to 600 DEG C with the cooling velocity of 30 DEG C/s or more after rolling；
Quenching：It is 814 DEG C that the austenite of steel, which starts phase transition temperature Ac3, is quickly heated up to the heating speed of 50 DEG C/min or more
840~860 DEG C, a length of 1~1.5min/mm when keeping the temperature after furnace temperature to temperature utilizes the quick water cooling of quenching press heat treatment equipment to room
Temperature；
Tempering：Quenched steel plate is heated to 200~240 DEG C, a length of 2~3min/mm, is air-cooled to when being kept the temperature after furnace temperature to temperature
Room temperature.
4. a kind of manufacturing method of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates according to claim 3, feature
It is：In the casting process, whole process uses argon for protecting pouring.
5. a kind of manufacturing method of yield strength 1100MPa grades of Ultra-fine Grained high strength steel plates according to claim 3, feature
It is：In the casting process, using electromagnetic agitation, stirring parameter 320A, 6Hz.
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| CN109385570A (en) * | 2018-09-28 | 2019-02-26 | 宝山钢铁股份有限公司 | A kind of high strength steel plate and its manufacturing method |
| CN110578095A (en) * | 2019-10-22 | 2019-12-17 | 马鞍山钢铁股份有限公司 | 1200 MPa-level hot-rolled ultrahigh-strength steel plate and manufacturing method thereof |
| CN110643800A (en) * | 2019-10-22 | 2020-01-03 | 马鞍山钢铁股份有限公司 | 1200 MPa-level hot-rolled high-strength dual-phase steel plate and manufacturing method thereof |
| CN113430454A (en) * | 2021-05-27 | 2021-09-24 | 武汉钢铁有限公司 | Welding steel with yield strength of more than or equal to 1200MPa and production method thereof |
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| CN109385570A (en) * | 2018-09-28 | 2019-02-26 | 宝山钢铁股份有限公司 | A kind of high strength steel plate and its manufacturing method |
| CN109385570B (en) * | 2018-09-28 | 2021-05-14 | 宝山钢铁股份有限公司 | High-strength steel plate and manufacturing method thereof |
| CN110578095A (en) * | 2019-10-22 | 2019-12-17 | 马鞍山钢铁股份有限公司 | 1200 MPa-level hot-rolled ultrahigh-strength steel plate and manufacturing method thereof |
| CN110643800A (en) * | 2019-10-22 | 2020-01-03 | 马鞍山钢铁股份有限公司 | 1200 MPa-level hot-rolled high-strength dual-phase steel plate and manufacturing method thereof |
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| CN113832414B (en) * | 2020-06-23 | 2023-03-14 | 宝山钢铁股份有限公司 | High-performance YP1100 MPa-level steel plate and manufacturing method thereof |
| CN113430454A (en) * | 2021-05-27 | 2021-09-24 | 武汉钢铁有限公司 | Welding steel with yield strength of more than or equal to 1200MPa and production method thereof |
| CN114480970A (en) * | 2022-01-25 | 2022-05-13 | 上海大学 | High-strength high-toughness steel and preparation method and application thereof |
| CN114686762A (en) * | 2022-03-30 | 2022-07-01 | 鞍钢股份有限公司 | Production method of high-strength and high-toughness hot continuous rolling thin steel plate with Brinell hardness of 500HBW |
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Application publication date: 20180921 |