CN110306123A - A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production method - Google Patents

A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production method Download PDF

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Publication number
CN110306123A
CN110306123A CN201910680367.5A CN201910680367A CN110306123A CN 110306123 A CN110306123 A CN 110306123A CN 201910680367 A CN201910680367 A CN 201910680367A CN 110306123 A CN110306123 A CN 110306123A
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tensile strength
hot forming
steel
1800mpa
rolling
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晋家春
詹华
崔磊
肖洋洋
谷海容
刘永刚
冷德平
马二清
董标
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Maanshan Iron and Steel Co Ltd
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Maanshan Iron and Steel Co Ltd
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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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0405—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing of ferrous alloys
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0436—Cold 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

The invention discloses a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production methods, belong to metallurgical technology field.Tensile strength >=1800MPa grade high ductility hot forming steel each component mass percent are as follows: C0.29~0.35%, Si≤0.5%, Mn0.5~1.5%, P≤0.020%, S≤0.010%, Cr≤0.50%, Al0.01~0.06%, Nb0.01~0.06%, V0.01~0.06%, Mo≤0.5%, remaining is Fe and inevitable impurity, it is produced by following technique, one, melting；Two, slab；Three, hot rolling；Four, cold rolling；Five, it anneals；Six, thermoforming.The present invention is added by special component alloying element, cooperates specific production technology, manufactures steel tensile strength >=1800MPa and has high tenacity and high cold-bending property.

Description

A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production method
Technical field
The invention belongs to metallurgical technology fields, more specifically to a kind of tensile strength >=1800MPa grades of high tenacity Hot forming steel and its production method.
Background technique
Automotive light weight technology technology is to adapt to one of Hyundai Motor safety, key technology of energy-saving and environmental protection trend, more next at present More automobile body parts uses hot forming techniques (such as: bumper, collision prevention girders, A column, B column, car door anti-collision thick stick Deng).Hot forming techniques are will to shape and strengthen a kind of new process for being divided into two step production superhigh intensity auto parts and components, raw The part of production has many advantages, such as superhigh intensity, formed precision height, without rebound.
Widely used hot forming steel is 1500MPa intensity rank currently on the market, with automobile energy consumption and security performance Laws and regulations it is more and more harsh and people deepen continuously to the research of automotive light weight technology, the higher hot forming of intensity rank Steel becomes research hotspot, and not requiring nothing more than thermoformed parts under complicated load-up condition has high intensity, while being also required to good Good plasticity and toughness.However, the usual intensity of hot forming steel is very high, but toughness is insufficient, intensity up to 1800MPa or more, and Elongation percentage only has 4% or so, and three-point bending angle is generally at 50 degree or less, it is difficult to reach using standard.
Find that China Patent Publication No.: publication date: CN106811689A on June 9th, 2017, discloses one kind through retrieval The preparation method of tensile strength >=2000MPa hot forming steel, the composition quality percentage composition of this steel are C:0.3~0.5%, Si:1.2~1.7%, Mn:1.4~2.0%, B:0.001~0.01%, Ti:0.05~0.1%, P :≤0.008%, S :≤ 0.005%, Cr:0.6~1.2%, Al:0.01~0.07%, Nb:0.01~0.08%, remaining for Fe and inevitably it is miscellaneous Prime element, raw material yield strength are 424MPa~588MPa, and tensile strength is 616MPa~760MPa, and elongation percentage A50 is 17.3%~20.4%；Yield strength is 1000MPa~1200MPa after hot forming, and tensile strength is >=2000MPa, elongation percentage The Mn of A50=8%~9%, main C, 1.2~1.7% Si, 1.4~2.0% by addition 0.3~0.5% is strong to improve Degree improves harden ability by the B of the Cr and 0.001~0.01% of addition 0.6~1.2%, and by addition 0.01~ 0.08% Nb improves elongation percentage；Make raw material strength reduction additionally by bell-type annealing, cutting before being conducive to hot forming Cut processing.However in the invention addition 1.4~2.0% Mn, banded structure is easy to produce, to the cold-bending property of part after forming It is unfavorable；The Si of addition 1.2~1.7%, it is unfavorable to quality control on the surface in practical hot rolling and cold-rolling process；Addition 0.6~ 1.2% Cr increases the risk of casting blank cleavage in continuous casting production process.
China Patent Publication No.: publication date: CN106811681A discloses a kind of no B hot forming steel on June 9th, 2017 Preparation method, the ingredient percent of steel is C:0.25~0.5% in the invention, Si:0.7~1.2%, Mn:0.5~ 1.3%, Al:0.01~0.08%, P :≤0.015%, S :≤0.008%, Cr:1.0~3.0%, Ti:0.02~0.09%, Mo:0.05~0.25%, Nb:0.02~0.09%, remaining is Fe and inevitable impurity element.The production technology of the invention It is 1200 DEG C of heating temperature, keeps the temperature 1h, finishing temperature: 870 DEG C, coiling temperature: 660 DEG C, is then heated to 900 DEG C, heat preservation Then 3min is quickly cooled to 260 DEG C, is then air-cooled to room temperature, obtain complete martensitic structure.The material that the invention obtains Although at low cost, the Si of addition 0.7~1.2% is unfavorable to quality control on the surface in practical hot rolling and cold-rolling process；Add The Cr for adding 1.0~3.0% increases the risk of casting blank cleavage in continuous casting production process；And the Ti of addition 0.02~0.09%, it is real The TiN of bulky grain can be precipitated in the production process of border, when application easily forms stress concentration point, unfavorable to the collision performance of part；Separately On the one hand, it batching using 660 DEG C, banded structure is obvious in finished-product material, and it is unfavorable to the cold-bending property of part, and high temperature coiling is not The abundant Dispersed precipitate of the precipitate of sharp Nb is precipitated, therefore is unfavorable for refining the effect of crystal grain in heat forming processes.
China Patent Publication No.: publication date: CN106119693A is disclosed and a kind of is used sheet billet on November 16th, 2016 The thin hot forming steel of Direct Rolling tensile strength >=2100MPa and production method, the composition quality percentage composition of this steel are C:0.41 ~0.50%, Si:0.45~0.65%, Mn:1.6~2.0%, B:0.004~0.005%, P :≤0.006%, S :≤ 0.004%, Cr:0.50~0.65%, Als:0.015~0.060%, Ti:0.046~0.060% or Nb:0.046~ 0.060%, Mo:0.36~0.60%, Ni:0.21~0.35%, N :≤0.004%, remaining is Fe and inevitable impurity Element.The invention the preparation method comprises the following steps: electric furnace or converter smelting, refining, continuous casting, 1230~1250 DEG C of heating temperature, finish to gauge temperature 880~920 DEG C, 585~615 DEG C of coiling temperature of degree.Material yield strength >=1450MPa of preparation, tensile strength >= 2100MPa, elongation A80 >=5%, the patent of invention be mainly short route preparation hot forming Steel material, compared to tradition steel-making~ Hot rolling~cold rolling~annealing process has the advantage of low cost.But the C of patent addition 0.41~0.50%, increases quenching The hardness of martensite, but actually it is unfavorable for the plasticity and toughness of part after forming；The Mn of addition 1.6~2.0%, is easy to produce band-like group It knits, it is unfavorable to the cold-bending property of part after forming；And the Ni of addition 0.21~0.35%, increase the cost of alloy of product；And Hot-rolled finished product raw material can have decarburized layer, and decarburized layer can be further aggravated after hot forming, and the type after part ball blast is made in influence Face size and surface quality.
Summary of the invention
1, it to solve the problems, such as
For the low problem of tensile strength >=1800MPa grades in the prior art of hot forming steel toughness, cold-bending property, originally Invention provides a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production method, passes through special component alloy The addition of element, cooperates specific manufacturing process, and tensile strength >=1800MPa grades of hot forming steel of manufacture have high tenacity High cold-bending property.
2, technical solution
To solve the above problems, the present invention adopts the following technical scheme that.
A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel, each component mass percent are as follows: C 0.29~ 0.35%, Si≤0.5%, Mn 0.5~1.5%, P≤0.020%, S≤0.010%, Cr≤0.50%, Al 0.01~ 0.06%, Nb 0.01~0.06%, V 0.01~0.06%, Mo≤0.5%, remaining is Fe and inevitable impurity.
The hot forming steel that usual tensile strength reaches 1800MPa or more has that intensity is very high but toughness is insufficient, Elongation only has 4% or so, and clod wash angle is generally also at 45 ° or less, it is difficult to meet performance requirement when auto parts and components use, This programme makes it while tensile strength reaches 1800Mpa or more by the improvement to hot forming composition of steel, toughness, clod wash Performance is able to satisfy the requirement of auto parts and components.
Further, each component mass percent are as follows: C 0.29~0.35%, Si 0.25~0.50%, Mn 1.02~ 1.5%, P 0.01%, S 0.003%, Cr 0.18~0.45%, Al 0.043~0.060%, Nb 0.031~0.040%, V 0.032~0.035%, Mo 0.15~0.20%, remaining is Fe and inevitable impurity.
C 0.29~0.35%, C play key effect to the formation of martensite in steel, can significantly improve the hardness of material Intensity, but with the raising of carbon content, the plasticity and toughness of material can be reduced, while will affect welding performance, carbon content mistake It is low and be difficult to meet the requirement of intensity, therefore this programme controls phosphorus content 0.29~0.35%, meets hot forming steel to tough The high demand of property, while its intensity is improved as far as possible.
Si 0.25~0.50%, Si plays the role of solution strengthening, can effectively facilitate C and spread to austenite, right Ferrite has significant catharsis, improves ferrite degree of purity in steel, and the Si of stable austenite tissue, too high levels can be reduced Toughness and welding performance, while being unfavorable in subsequent hot rolled, cold-rolled process the control of surface quality, therefore this programme will be siliceous Amount control is 0.25~0.50%.
The stability of austenite can be improved in Mn 1.02~1.5%, Mn, improves the harden ability of material, while increasing material Hardness, the too low steel that cannot get required intensity of Mn content, a large amount of Mn can reduce the welding performance and low-temperature flexibility of material, The addition of Mn influences whether the clod wash of part after final molding so that steel are easy to produce banded structure in continuous casting process simultaneously Performance, therefore this programme controls manganese content 1.02~1.5%.
P 0.01%, S 0.003%, P, S are the harmful elements during steel are smelted, P and S can reduce crystal boundary surface can and Crystal boundary cohesive force is reduced, increase steel brittle fracture tendency, has an adverse effect to steel plasticity toughness, while vulcanizing in steel Object is very big on the influence of steel cold-bending property, therefore it is 0.003% that this programme control P content, which is 0.01%, S content,.
Cr 0.18~0.45%, Cr can significantly improve the intensity, hardness and wearability of steel, but can reduce plasticity And toughness, while Cr content is more than the risk of casting blank cleavage in continuous casting production process to be increased after 0.45%, therefore this programme will Chrome content is controlled 0.18~0.45%.
Al 0.043~0.060%, when smelting, Al element is added in alloy material as deoxidier, a small amount of aluminium member Element can refine crystal grain, improve impact flexibility, aluminium element addition excessively will affect the welding performance of material, therefore this programme will contain Aluminum amount is controlled 0.043~0.060%.
Nb0.031~0.040%, Nb play the role of refining crystal grain and precipitation strength, Nb can be formed in steel NbC or The gaps such as NbN interphase to anchoring of dislocation and prevents the migration of sub boundary in recrystallization process because of NbC, NbN The effects of, to considerably increase the time of recrystallization, and then achieve the purpose that fining austenite grains, the additive amount of Nb is too small When, it is unobvious to the invigoration effect of performance, it is also no longer obvious to the contribution of Strengthening and Toughening when its adding too much, therefore we The content that case controls niobium is 0.031~0.040%.
V 0.032~0.035%, V mainly plays solution strengthening, can fix the N element in steel, reduces in steel certainly By the content of nitrogen, reduce the harm of N element in steel, avoid the generation of aging phenomenon, but when V content is excessive can accelerate pearlite It is formed, therefore this programme control V content is 0.032~0.035%.
Mo 0.15~0.20%, Mo can refine crystal grain and improve the intensity and hardness of steel, and can improve quenching for steel Permeability and thermostrength, it is unobvious to the improvement result of performance when Mo content is lower, when content is high, it is easy to produce ferrite δ phase Or other brittlement phases and reduce toughness, therefore this programme control Mo content be 0.15~0.20%.
Further, there are following relationships between constituent mass:
6.8≤Mn/Mo≤7.5；
And 0.97≤Nb/V≤1.14.
The intensity needed in order to obtain, the application joined the intensity that Mn member usually improves steel, but the steel containing Mn, It is easy to produce banded structure in continuous casting process, influences the cold-bending property of final finished, applicants have found that, special component Mo and Mn element cooperation addition after the structural constituent in slab can be made to be more evenly distributed, to mitigate generation banded structure Risk, while in steel generate brittlement phase probability be greatly reduced, when there are reachable when following relationship for the addition of Mn and Mo To this effect: 6.8≤Mn/Mo≤7.5；Nb, V kind element be individually added into or not proportional addition when, plate property is promoted equal There are limitation, the complete solid solubility temperature of Nb is higher, therefore when soaking temperature is not high, though the addition of Nb element can refine crystalline substance Grain, but the intensity of steel plate can not be effectively improved, the solid solubility temperature of V is low, can rise in the not high temperature range of soaking temperature To precipitation enhancement, the adding proportion that this programme controls Nb and V is 0.97≤Nb/V≤1.14, in this range, when being in When different soaking temperature, there is element and playing solution strengthening or refinement crystal grain, in steel plate subsequent thermal processing process In, under different temperature fluctuations, can it is effective in inhibit the Deformation recrystallization of austenite and prevent growing up for its crystal grain, simultaneously The effect of stable performance precipitation strength, be easy to get the steel plate to match to high-intensitive and high tenacity, achievees the effect that complex intensifying.
Further, each component mass percent are as follows: C 0.31%, Si 0.26%, Mn 1.20%, P 0.01%, S 0.003%, Cr 0.18%, Al 0.045%, Nb 0.036%, V 0.035%, Mo 0.18%, remaining is Fe and can not keep away The impurity exempted from.There is most preferred intensity and tough at being grouped as manufactured steel plate after lower melting resulting alloy treatment processing at this The cooperation of property performance, and its clod wash degree highest.
A kind of production method of tensile strength >=1800MPa grades of high-toughness hot forming steel, process flow are as follows:
One, melting；
Two, slab；
Three, hot rolling: to slab carry out hot rolling, wherein tapping temperature be 1000~1250 DEG C, finishing temperature be 850~ 900℃；
Four, cold rolling: cold continuous rolling is carried out to product after hot rolling, wherein cold roling reduction >=50%；
Five, it anneals: continuous annealing being carried out to product after cold rolling, annealing temperature is 700~820 DEG C；
Six, thermoforming: product carries out heat stamping and shaping after annealing, and heating temperature is 800~1000 DEG C, heating time 3 ~10min, dwell time are 4~10s, quench cooling velocity >=25 DEG C/s.
The high cold-bending property automobile steel of the application by slab after the element melting by special component, then to slab into Row hot rolling, it is 1000~1250 DEG C that this programme, which controls hot rolling tapping temperature, and finishing temperature is 850~900 DEG C, can be in certain journey It is austenite homogenization on degree, reduces the segregation of C；Product after hot rolling carries out cold continuous rolling, controls cold roling reduction >=50%, Shen It asks someone to affect plate property studies have shown that the crystal grain in steel becomes thick when cold roling reduction < 50%；Production after cold rolling Object makes deformed grains be re-converted to uniform equi-axed crystal, eliminates simultaneously in (700~820 DEG C) progress continuous annealings of two-phase section Processing hardening and residual internal stress；Heat stamping and shaping processing is carried out after annealing, heating temperature is 800~1000 DEG C in this programme, Heating time is 3~10min, and with the raising of heating temperature, yield strength and tensile strength are increased, and elongation percentage is gradually Heating time control can be increased the harden ability of steel plate by decline in 3~10min, further, by controlling the dwell time In 4~10s, cooling velocity >=25 DEG C/s is quenched, the uniformity organized in steel plate can be improved, further refine crystal grain.
Further, coiling temperature is 500~600 DEG C in the hot rolling technology.It is added in steel plate in the application 0.031~0.040% Nb is batched in this temperature range, and the abundant Dispersed precipitate of precipitate for being conducive to Nb is precipitated, favorably In refining crystal grain in heat forming processes, further, the steel plate in the application uses low Si, low Mn, low Cr, no Ti, no B, Add the ingredient of Mo to design, cooperates with the coiling technique and continuous annealing process of this programme, tensile strength >=1800MPa grades of acquisition For steel without banded structure, ingredient is uniform, and toughness is high, while improving production efficiency.In addition, your gold is the design of the application ingredient be free of Belong to the elements such as Ni, steel product cost is lower, and melting, processing technology are easier to control, while that there is no raw material skin decarburizations etc. is negative Problem advantageously ensures that the molding surface size and surface quality of thermoformed parts.
Further, before cold-rolling process, pickling operation is carried out to product after hot rolling.By pickling operation, remove hot rolled The iron scale generated in journey is further ensured that the quality of final finished.
3, beneficial effect
Compared with the prior art, the invention has the benefit that
(1) a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, by its constitution element at The improvement divided makes the product strength being finally made reach 1800MPa or more, and have under the premise of guaranteeing reasonable manufacturing cost There are high tenacity, ductility, while there has also been large increases for cold-bending property；
(2) a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, 6.8≤Mn/Mo≤7.5 are special The structural constituent in slab can be made to be more evenly distributed after determining Mo and Mn element the cooperation addition of ingredient, to mitigate generation band The risk of shape tissue, while the probability that brittlement phase is generated in steel is greatly reduced, and further improves the toughness of final finished And cold-bending property；
(3) a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, passes through two kinds of element spies of Nb, V Determine cooperation addition in range, reciprocation between each element, to the effect of complex intensifying；
(4) production method of a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, excessively to heat It rolls, cold rolling, annealing, the control of each parameter of thermoforming, homogenizes product austenite, further refine crystal grain, it is equal to improve tissue Even property has obtained tensile strength, yield strength, elongation percentage high performance products up to standard；
(5) production method of a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, using suitable Coiling temperature, the abundant Dispersed precipitate of precipitate for being conducive to Nb is precipitated, is conducive to refine crystal grain in heat forming processes；
(6) production method of a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, steel plate use Low Si, low Mn, low Cr, no Ti, no B add the ingredient of Mo to design, and cooperate with the coiling technique and continuous annealing process of this programme, For tensile strength >=1800MPa grades of steel of acquisition without banded structure, ingredient is uniform, and toughness is high, while improving production efficiency.
Detailed description of the invention
Fig. 1 is the rolled microscopic structure obtained after embodiment 1 is batched；
Fig. 2 is the rolled microscopic structure obtained after embodiment 3 is batched；
Fig. 3 is the microscopic structure of 1 annealed state of embodiment；
Fig. 4 is the microscopic structure of 3 annealed state of embodiment；
Fig. 5 is the microscopic structure before 1 hot forming of embodiment quenching；
Fig. 6 is the microscopic structure before 3 hot forming of embodiment quenching；
Fig. 7 is the microscopic structure of 2 hot forming quenching state of embodiment.
Specific embodiment
The present invention is further described below with attached drawing combined with specific embodiments below.
Embodiment 1
A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel of the invention, each component mass percent are as follows: C 0.29~0.35%, Si≤0.5%, Mn 0.5~1.5%, P≤0.020%, S≤0.010%, Cr≤0.50%, Al 0.01 ~0.06%, Nb 0.01~0.06%, V 0.01~0.06%, Mo≤0.5%, remaining is Fe and inevitable impurity.
It is produced using following process flow:
One, melting；
Two, slab；
Three, hot rolling: to slab carry out hot rolling, wherein tapping temperature be 1000~1250 DEG C, finishing temperature be 850~ 900 DEG C, coiling temperature is 500~600 DEG C；
Four, cold rolling: pickling is carried out to product after hot rolling, then cold continuous rolling, wherein cold roling reduction >=50%；
Five, it anneals: continuous annealing being carried out to product after cold rolling, annealing temperature is 700~820 DEG C；
Six, thermoforming: product carries out heat stamping and shaping after annealing, and heating temperature is 800~1000 DEG C, heating time 3 ~10min, dwell time are 4~10s, quench cooling velocity >=25 DEG C/s.
As shown in table 1, Examples 1 to 6 selects the element of 6 groups of heterogeneities to carry out melting respectively, respectively by each embodiment After different elemental constituent meltings, by the technological parameter of table 2 carry out slab, hot rolling, cold rolling, after annealing, obtained properties of product As shown in table 3.
1 steel chemical component of table, wt%
Embodiment C Si Mn P S Al Cr Nb Mo N V
1 0.29 0.25 1.50 0.01 0.003 0.045 0.45 0.040 0.20 0.0040 0.032
2 0.31 0.26 1.20 0.01 0.003 0.045 0.18 0.036 0.18 0.0025 0.035
3 0.33 0.25 1.02 0.01 0.003 0.045 0.18 0.038 0.17 0.0035 0.032
4 0.35 0.25 1.45 0.01 0.003 0.043 0.20 0.031 0.15 0.0050 0.033
5 0.29 0.25 0.50 0.01 0.003 0.010 0.18 0.010 0.15 0.0025 0.010
6 0.35 0.50 1.50 0.02 0.010 0.060 0.50 0.060 0.50 0.0050 0.060
2 steel manufacturing process parameter of table
Embodiment Tapping temperature DEG C Finishing temperature DEG C Coiling temperature DEG C Annealing temperature DEG C
1 1236 891 550 782
2 1235 890 551 782
3 1240 886 652 781
4 1235 888 649 782
5 800 850 500 700
6 1250 900 600 820
Properties of product before 3 heat forming technology of table
Embodiment Yield strength Mpa Tensile strength Mpa Elongation percentage %
1 505 782 21
2 511 778 20.5
3 451 611 23
4 436 604 23
5 413 746 22
6 477 633 21
By carrying out microstructure observation's discovery to the steel before hot forming, obtained after being batched as shown in Figure 1 for embodiment 1 Rolled microscopic structure, wherein banded structure is unobvious, and it is micro- to be illustrated in figure 2 the rolled obtained after embodiment 3 is batched Tissue, banded structure is obvious, comparison diagram 1 and Fig. 2, and lower coiling temperature improves significantly work to the banded structure of raw material With the improvement of banded structure is conducive to the cold-bending property of part after raising hot forming, and Fig. 3 is micro- group of 1 annealed state of embodiment It knits, Fig. 4 is the microscopic structure of 3 annealed state of embodiment, and the performance of product finds different before comparison diagram 3 and Fig. 4 and heat forming technology Coiling temperature is on final annealing state end properties almost without influence.
Hot forming is carried out to the steel obtained by table 1,2 parameter of table according to technological parameter as shown in table 4, obtains product It can be as shown in table 5.
4 heat forming technology parameter of table
Embodiment Thermoforming heating temperature DEG C Thermoforming heating time min Dwell time s Quench cooling velocity DEG C/s
1 930 5 5 32
2 930 5 7 35
3 930 5 4 33
4 930 5 6 32
5 800 3 3 25
6 1000 10 10 35
Performance after 5 hot forming of table
Embodiment Yield strength Mpa Tensile strength Mpa Elongation percentage % Cold-bending property °
1 1204 1815 5.6 52
2 1266 1878 5.6 55
3 1279 1910 5.8 45
4 1317 1902 5.4 43
5 1211 1810 5.2 53
6 1193 1825 5.7 47
It is illustrated in figure 5 microscopic structure of the embodiment 1 before hot forming quenching, Fig. 6 is embodiment 3 before hot forming quenching Microscopic structure, Fig. 7 be 2 hot forming quenching state of embodiment microscopic structure, from microscopic structure as can be seen that after heat forming technology It obtains being complete quenching state martensitic structure, shows that final products have high intensity, 2 parameter of embodiment is obtained final Its clod wash angle that product carries out cold-bending property test is 55 °, shows that final products have high-ductility, to sum up, what embodiment 2 obtained Product has the comprehensive performance of the high cold-bending property of high-intensity and high-tenacity.
Pass through the properties discovery of final products under comparison each component and parameter, each component mass percent are as follows: C 0.31%, Si0.26%, Mn 1.20%, P 0.01%, S 0.003%, Cr 0.18%, Al 0.045%, Nb 0.036%, V 0.035%, Mo0.18%, remaining is Fe and inevitable impurity, the steel of the ingredient, through each work in embodiment 2 The product obtained after skill parameter processing, yield strength, tensile strength, elongation percentage and microhardness can reach required high standard Standard, intensity is high, and toughness is high, and clod wash angle is maximum, and cold-bending property is best, is the most preferred embodiment.
Example of the present invention is only that preferred embodiments of the present invention will be described, not to present inventive concept and Range is defined, and under the premise of not departing from design philosophy of the present invention, this field engineers and technicians are to technology of the invention The various changes and improvements that scheme is made should all fall into protection scope of the present invention.

Claims (7)

1. a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel, which is characterized in that each component mass percent are as follows: C 0.29~0.35%, Si≤0.5%, Mn 0.5~1.5%, P≤0.020%, S≤0.010%, Cr≤0.50%, Al 0.01 ~0.06%, Nb 0.01~0.06%, V 0.01~0.06%, Mo≤0.5%, remaining is Fe and inevitable impurity.
2. a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel according to claim 1, which is characterized in that Each component mass percent are as follows: C 0.29~0.35%, Si 0.25~0.50%, Mn 1.02~1.5%, P 0.01%, S 0.003%, Cr 0.18~0.45%, Al 0.043~0.060%, Nb 0.031~0.040%, V 0.032~0.035%, Mo 0.15~0.20%, remaining is Fe and inevitable impurity.
3. a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel according to claim 2, which is characterized in that There are following relationships between its constituent mass:
6.8≤Mn/Mo≤7.5；
And 0.97≤Nb/V≤1.14.
4. a kind of tensile strength >=1800MPa grades of high-toughness hot forming steel according to claim 3, which is characterized in that Each component mass percent are as follows: C 0.31%, Si 0.26%, Mn 1.20%, P 0.01%, S 0.003%, Cr 0.18%, Al 0.045%, Nb 0.036%, V 0.035%, Mo 0.18%, remaining is Fe and inevitable impurity.
5. a kind of production method of tensile strength >=1800MPa grades of high-toughness hot forming steel, which is characterized in that process flow is such as Under:
One, melting；
Two, slab；
Three, hot rolling: carrying out hot rolling to slab, and wherein tapping temperature is 1000~1250 DEG C, and finishing temperature is 850~900 DEG C；
Four, cold rolling: cold continuous rolling is carried out to product after hot rolling, wherein cold roling reduction >=50%；
Five, it anneals: continuous annealing being carried out to product after cold rolling, annealing temperature is 700~820 DEG C；
Six, thermoforming: after annealing product carry out heat stamping and shaping, heating temperature be 800~1000 DEG C, heating time be 3~ 10min, dwell time are 4~10s, quench cooling velocity >=25 DEG C/s.
6. a kind of production method of tensile strength >=1800MPa grades of high-toughness hot forming steel according to claim 5, Be characterized in that: coiling temperature is 500~600 DEG C in the hot rolling technology.
7. a kind of production method of tensile strength >=1800MPa grades of high-toughness hot forming steel according to claim 5, It is characterized in that: before cold-rolling process, pickling operation being carried out to product after hot rolling.
CN201910680367.5A 2019-07-26 2019-07-26 A kind of tensile strength >=1800MPa grades of high-toughness hot forming steel and its production method Pending CN110306123A (en)

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CN111041382A (en) * 2019-12-03 2020-04-21 马鞍山钢铁股份有限公司 1800 MPa-grade non-coating hot forming steel with low high-temperature friction coefficient and preparation method thereof
CN111235483A (en) * 2020-03-12 2020-06-05 中国汽车工程研究院股份有限公司 Niobium-vanadium composite microalloyed hot forming steel and production and hot stamping forming method thereof
CN112210724A (en) * 2020-08-10 2021-01-12 唐山钢铁集团有限责任公司 ESP (electronic stability program) production-based high-strength hot forming steel and method
CN112226690A (en) * 2020-09-30 2021-01-15 鞍钢股份有限公司 Pickled steel plate for 1800 MPa-level hot stamping wheel rim and manufacturing method thereof
CN112251669A (en) * 2020-09-30 2021-01-22 鞍钢股份有限公司 Hot rolled steel plate for 2000 MPa-level hot stamping wheel spoke and manufacturing method thereof
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CN113106338A (en) * 2021-03-22 2021-07-13 北京科技大学 Preparation method of ultrahigh-strength high-plasticity hot stamping formed steel
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CN111235483A (en) * 2020-03-12 2020-06-05 中国汽车工程研究院股份有限公司 Niobium-vanadium composite microalloyed hot forming steel and production and hot stamping forming method thereof
CN112210724A (en) * 2020-08-10 2021-01-12 唐山钢铁集团有限责任公司 ESP (electronic stability program) production-based high-strength hot forming steel and method
CN112210724B (en) * 2020-08-10 2022-02-18 唐山钢铁集团有限责任公司 ESP (electronic stability program) production-based high-strength hot forming steel and method
CN112267067B (en) * 2020-09-30 2022-02-18 鞍钢股份有限公司 Hot rolled steel plate for 2000 MPa-level hot stamping wheel rim and manufacturing method thereof
CN112226690A (en) * 2020-09-30 2021-01-15 鞍钢股份有限公司 Pickled steel plate for 1800 MPa-level hot stamping wheel rim and manufacturing method thereof
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CN112251669A (en) * 2020-09-30 2021-01-22 鞍钢股份有限公司 Hot rolled steel plate for 2000 MPa-level hot stamping wheel spoke and manufacturing method thereof
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CN113957350A (en) * 2021-10-26 2022-01-21 江苏沙钢集团有限公司 2000 MPa-grade hot forming steel and production method thereof
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Application publication date: 20191008