CN108315662B - Hot rolled steel plate with yield strength of 900MPa and production process thereof - Google Patents
Hot rolled steel plate with yield strength of 900MPa and production process thereof Download PDFInfo
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- CN108315662B CN108315662B CN201810294415.2A CN201810294415A CN108315662B CN 108315662 B CN108315662 B CN 108315662B CN 201810294415 A CN201810294415 A CN 201810294415A CN 108315662 B CN108315662 B CN 108315662B
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 133
- 239000010959 steel Substances 0.000 title claims abstract description 133
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 238000005096 rolling process Methods 0.000 claims abstract description 40
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 17
- 239000011575 calcium Substances 0.000 claims abstract description 7
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 5
- 238000003723 Smelting Methods 0.000 claims abstract description 5
- 238000005266 casting Methods 0.000 claims abstract description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 230000009467 reduction Effects 0.000 claims description 11
- 238000005516 engineering process Methods 0.000 claims description 9
- 238000002791 soaking Methods 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 238000010583 slow cooling Methods 0.000 claims description 2
- 238000003466 welding Methods 0.000 abstract description 11
- 229910052719 titanium Inorganic materials 0.000 abstract description 10
- 229910052720 vanadium Inorganic materials 0.000 abstract description 9
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 7
- 229910052758 niobium Inorganic materials 0.000 abstract description 6
- 238000005452 bending Methods 0.000 abstract description 4
- 229910052748 manganese Inorganic materials 0.000 abstract description 3
- 229910052717 sulfur Inorganic materials 0.000 abstract description 3
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 2
- 229910052782 aluminium Inorganic materials 0.000 abstract 1
- 229910052804 chromium Inorganic materials 0.000 abstract 1
- 229910052742 iron Inorganic materials 0.000 abstract 1
- 229910052710 silicon Inorganic materials 0.000 abstract 1
- 238000000034 method Methods 0.000 description 26
- 229910001566 austenite Inorganic materials 0.000 description 16
- 230000008569 process Effects 0.000 description 13
- 239000010955 niobium Substances 0.000 description 12
- 230000000694 effects Effects 0.000 description 11
- 238000001556 precipitation Methods 0.000 description 9
- 238000005275 alloying Methods 0.000 description 7
- 239000013078 crystal Substances 0.000 description 6
- 238000005496 tempering Methods 0.000 description 6
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000001953 recrystallisation Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 229910001563 bainite Inorganic materials 0.000 description 3
- 238000006477 desulfuration reaction Methods 0.000 description 3
- 230000023556 desulfurization Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- RMLPZKRPSQVRAB-UHFFFAOYSA-N tris(3-methylphenyl) phosphate Chemical compound CC1=CC=CC(OP(=O)(OC=2C=C(C)C=CC=2)OC=2C=C(C)C=CC=2)=C1 RMLPZKRPSQVRAB-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 241001062472 Stokellia anisodon Species 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910011214 Ti—Mo Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 150000001721 carbon Chemical class 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 230000007786 learning performance Effects 0.000 description 1
- 208000020442 loss of weight Diseases 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000000930 thermomechanical effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing 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
- 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
-
- 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
- C22C38/02—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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
The invention discloses a hot rolled steel plate (coil) with the yield strength of 900MPa and a production process thereof, wherein the mass percentage contents and CEV of C, Si, Mn, P, S, Cr, Mo, V, Ti, Nb and Al of the steel are well controlled. Smelting the pretreated blast furnace desulfurized molten iron in a converter, processing the smelted qualified molten steel by LF + RH + calcium, continuously casting the molten steel into a steel billet, heating the steel billet in a heating furnace to 1150-1300 ℃, rolling the steel billet into a steel plate, wherein the final rolling temperature is 830-890 ℃, ultra-fast cooling the steel plate after the steel billet is subjected to final rolling at a cooling speed of 100-300 ℃/S, and cooling the steel plate to 560-660 ℃ by a 10-25 ℃/S laminar cooling method. And rolling the final-cooled steel plate into a steel coil at 560-660 ℃. The transverse and longitudinal tensile strength of the steel coil (plate) obtained by the production process is more than or equal to 900MPa, the transverse and longitudinal elongation is more than or equal to 15 percent, and the transverse and longitudinal Charpy impact energy AKv (-40 ℃) is more than or equal to 27J. The steel plate is widely used for the carriage and the structural member of the light-weight dumper and has good welding performance and bending performance.
Description
Technical field
The present invention relates to a kind of hot-rolling high-strength steel plate and its production technologies, more particularly to one kind to be applied to commercial vehicle (such as
Body of tipper carriage etc.) yield strength be 900MPa level hot rolled steel plate (volume) and its production technology.
Background technique
High-strength steel sheet is applied to the lightweight of engineering machinery and commercial vehicle, in particular with national standard GB1589-2016's
Formal publication and implementation, propose higher loss of weight demand to material in terms of the lightweight of commercial vehicle.900MPa grades of yield strength
Or more high-strength steel sheet be widely used to the structural member of commercial vehicle.Only to compartment plate gauge in national standard GB/T33963-2017
Surely the intensity of 700Mpa rank has been arrived, intensity is up the abrasion-resistant stee of quenched and tempered state.It is defined in national standard GB/T16270-2009 in the wrong
Take the mechanical property and carbon equivalent standard of 890MPa grades of quenched and tempered state high-strength steel of intensity.Its yield strength >=890MPa, tensile strength
940 ~ 1100MPa and elongation percentage >=11%, meet -40 DEG C of impact of collision function > 34J, and the carbon equivalent ce V satisfaction of steel is less than or equal to
0.72% requirement.
The manufacturing technology of high-strength steel sheet is mainly controlled rolling and controlled cooling (TMCP) and quenched (Q+T).TMCP(Thermo-
Mechanical Control Process) by two-phase control rolling temperature, drafts and the cooling technique of control steel plate, it is formed
Specific microstructure, to obtain good mechanical performance.At present TMCP technique production high-strength steel be mainly 700Mpa and its with
Under, the high-strength steel of 700Mpa or more is produced by hardening and tempering process, and hardening and tempering process is steel plate in heating austenite
Enter rolling mill practice after homogenization, is rolled down to air-cooled after specified thickness.The air-cooled steel plate to after room temperature enters heating furnace, specified
Quenching is cooled to room temperature after temperature austenitizing, and quenched steel plate enters back into tempering furnace and is reheated to assigned temperature, heat preservation
It comes out of the stove after a certain period of time air-cooled.Hardening and tempering process production high-strength steel sheet is by the quenching process refinement after austenitizing, finally
For martensitic structure, carbon is discharged from supersaturated ferrite using tempering process, is formed simultaneously tiny carbide, improves
The internal stress and low-temperature impact toughness of steel plate.Although hardening and tempering process can obtain high intensity and excellent mechanical property, it is given birth to
Long flow path is produced, energy consumption is big, complex process.
Due to the development of the industries such as heavy load truck, engineering machinery, the requirement of load-carrying and mechanical strength to vehicle is constantly mentioned
Height, while also requiring to mitigate self weight, therefore it is required that, intensity rank lower using the cost better superelevation of high and low temperature impact flexibility
Strength steel sheet.
Summary of the invention
The purpose of the present invention is to provide a kind of 900MPa grades of yield strength (Rel) and there are superior weldability energy, elongation percentage
And hot rolled steel plate (volume) and its production technology compared with high-tensile (Rm).
To achieve the above object, the technical solution adopted by the present invention is that: a kind of yield strength 900MPa grades of hot rollings
Steel plate (volume), its Design of Chemical Composition are C=0.08~0.15 (in terms of wt%), Si=0.10~0.40, Mn=1.30~2.0, P
≤ 0.015, S≤0.005, Mo=0.20~0.50, V=0.10~0.20, Ti=0.10~0.20, Nb=0.015~0.050, Al=
0.02~0.07, surplus is Fe and other inevitable impurity, carbon equivalent ce V≤0.55% of steel.
A kind of production technology of yield strength 900MPa level hot rolled steel plate (volume) includes following procedure: through desulfurization
It is pretreated it is blast-melted pour into oxygen top bottom blowing converter and smelted, by qualified smelting molten steel through Argon, vacuum
And steel billet is casting continuously to form by conticaster after Calcium treatment.The steel billet being casting continuously to form is sent into soaking pit or heating furnace and is heated, when steel billet plus
Heat is to soaking time >=15min after 1150~1300 DEG C.
Steel billet after heating is rolled: roughing, 5~7 passage of roughing, the single track of roughing mill are carried out to the steel billet of heating
Secondary reduction ratio >=15%, total reduction of the steel billet on roughing mill are 70~85%.Steel billet becomes intermediate base after roughing.After roughing
Intermediate base enter finishing tandem rolling unit finish rolling, intermediate base entry temperature at finishing control is between 1000~1100 DEG C, finishing tandem rolling unit
Single chassis reduction ratio >=10%, the total reduction of intermediate base is 75~97%.Finishing temperature control of the intermediate base in finishing tandem rolling unit
For system at 820~900 DEG C, steel plate thickness of the intermediate base after finishing tandem rolling unit finish rolling is 1.2~10.0mm, the steel plate after finish rolling with
100~300 DEG C/S of cooling velocity carries out ultra-rapid cooling, and steel plate is cooled to 560 in the method for 10~25 DEG C/s section cooling
~660 DEG C.Steel plate coils into coil of strip under the conditions of 560~660 DEG C.
It is cold or be slowly cooled to room temperature that offline coil of strip is subjected to heap.
A kind of yield strength 900MPa level hot rolled steel plate (volume) and its production technology that are there is provided using technical solution as above and
The prior art is compared, and has the technical effect that 1. a kind of yield strength 900MPa level hot rolled steel plate (volume) provided by the invention is not only
Elongation percentage with higher and tensile strength also have excellent Bending Processing performance and welding performance；What 2. the present invention designed
Integral Thought is to add the component system of V-Ti-Mo and the process system of controlled rolling and controlled cooling using low C, is matched by alloying element
Between optimization, make full use of technique to act on the raising of steel plate obdurability, production has compared with low-carbon-equivalent (CEV≤0.55%)
High strength steel plate；It obtains the disperse on ultra-fine grained ferrite matrix of the crystallite dimension less than 5 μm and issues the left side partial size about 5nm
The microstructure of right microalloy precipitated phase so that steel plate yield strength can reach under the conditions of hot continuous rolling 900Mpa grades with
On, transverse and longitudinal elongation >=15%, transverse and longitudinal Charpy-V impact power AKv (- 40 DEG C) >=27J rolls at rear quenched heat so as to cancel
Reason.Advantage is to simplify Production Flow Chart, reduces energy consumption, reduces steel plate internal stress；3. in addition to good welding performance,
Also there is the buckling performance more excellent than hardened and tempered steel plate, elongation percentage.
Specific embodiment
A specific embodiment of the invention is described in further detail below.
A kind of yield strength 900MPa level hot rolled steel plate (volume) of the present invention chemical component proportion (wt%) be C=
0.08~0.15, Si=0.10~0.40, Mn=1.30~2.0, P≤0.015, S≤0.005, Mo=0.20~0.50, V=0.10
~0.20, Ti=0.10~0.20, Nb=0.015~0.050, Al=0.02~0.07, surplus be Fe and it is other inevitably it is miscellaneous
Matter；Carbon equivalent (CEV)≤0.55%.Wherein the calculation formula of carbon equivalent ce V is CEV(%)=C+Mn/6+ (Mo+Cr+V)/5+ (Ni+
Cu)/15。
The addition principle of chemical element is as follows in the present invention.
C:C content difference has important influence: the higher steel grade of C content in the phase transformation of cooling procedure to steel plate, same
Under the cooling condition of sample, the higher tissue of bainite or martensite equal strength easy to form in cooling procedure；But C content is too high,
It then will form more crisp tissue, reduce the low-temperature impact toughness of steel plate, on the other hand, C content is too low, ferrite easy to form etc.
The lower tissue of intensity.Suitable C and Ti, Nb, Mo form stable MC nanoscale precipitate, can produce strong precipitation strength
The effect of effect and refined crystalline strengthening, increases substantially armor plate strength；To reach yield strength 900Mpa or more and other comprehensive power
The considerations of learning performance and processing performance etc., the present invention control C content within the scope of 0.08~0.15wt%.
Si:Si element solid solution improves the intensity of steel plate in steel.Si too high levels can inhibit the formation of cementite, simultaneously
Higher Si content can deteriorate the welding performance of steel plate.Therefore, the Si content control in the present invention is 0.10~0.40wt%.
Mn:Mn is weak carbide formation element, is usually solid-solubilized in steel, and the effect of solution strengthening is played.Using controlled rolling control
The high-strength steel sheet that cold mode produces, Mn element pass through across diffusion interface dissipation free energy, inhibit the diffusion of sheet phase end face
Control is grown up, and the sheet lath of bainite of refinement is formed, to improve the comprehensive performances such as intensity and the toughness of steel plate.Mn content
It is excessively high to will lead to slab tearing tendency increasing, it is easy the defects of lobe is formed in slab production process, and Mn content is lower then
It is smaller to the contribution of intensity, therefore C element or other expensive alloying elements such as Mo element etc. must be added to guarantee the strong of steel plate
Degree.Addition C element can deteriorate the welding performance of steel plate, and steel plate cost can be improved by adding other noble elements.Therefore, in the present invention
1.30~2.0wt%Mn element is added, makes steel plate that there is good obdurability.
Mo:Mo element is solid-solubilized in steel in austenitizing, in the hot rolling there is certain delay austenite to tie again
Crystalline substance effect, improves the defect density in deformed austeaite, in cooling procedure can be by inhibiting diffusion Interface Motion to realize refinement
Final tissue.The free energy that Mo element dissipates to diffusion interface effect of dragging is approximately 3 times of Mn element, is helped in coiling process
In being precipitated jointly with V, Ti, nanoscale (V, Ti, Mo) C complex precipitates are formed, significant precipitation enhancement is generated.When Mo contains
When amount is lower than 0.20 wt%, above-mentioned effect is smaller, and when more than 0.45wt%, function and effect reach saturation, while Mo element is valuable
The Mo of 0.20~0.45wt% is added to guarantee plate property and cost in alloying element in the present invention.
V:V is ferritisey, strongly diminution austenitic area.The V element that high temperature dissolves in austenite can increase steel
Harden ability.The carbide V4C3 of V element is more stable in steel, can inhibit crystal boundary is mobile to grow up with crystal grain.V element and Cu member
Element has all been precipitation enhancement in steel, but for opposite Cu element, minimal amount of V element only need to be added, that is, can reach
Same precipitation strength effect.In addition, Cu element easily causes grain-boundary crack in steel；It thus must be added at least up to one
The Ni element of half content, ability Crack prevention, and Ni element is equally sufficiently expensive alloying element, therefore, is replaced with V element
The manufacturing cost of steel can be greatly lowered in Cu element.When V content is lower than 0.10wt%, the precipitation strength increment of generation is insufficient
So that the yield strength of steel plate reaches 900Mpa, when V content is more than 0.20wt%, function and effect reach saturation, and cost compared with
It is high.Therefore, the V element of 0.10~0.20wt% is added in the present invention to guarantee to have higher yield strength.
Ti:Ti and N form TiN at high temperature, and when heating of plate blank austenitizing, TiN can inhibit Austenite Grain Growth.Heat
During rolling, Ti and C form nanoscale TiC in lower temperature section, tiny TiC particle have significant precipitation strength and
Refined crystalline strengthening effect is conducive to the intensity and low temperature impact properties that improve steel plate, while Ti and V, Mo are common in coiling process
It is precipitated, forms nanoscale (V, Ti, Mo) C complex precipitates.But works as Ti too high levels, on the one hand then will form coarse rectangular
TiN is precipitated, and steel plate stress in stress is concentrated near TiN particle, and the forming core for becoming micro-crack is grown up source, reduces steel plate
Fatigue behaviour.On the other hand cause Ti during (continuous casting) heating steel billet to be difficult to be dissolved since TiC solubility product is smaller, rise not
To corresponding effect.In summary, the Ti content in the present invention controls within the scope of 0.10~0.20wt%.
Nb: steel plate will form the defects of a large amount of dislocation during the rolling process.Austenite occurs under the action of defect energy
Recrystallization, recrystallization process include the forming core of the new crystal grain of austenite and grow up, and Nb element is by inhibiting Austenite Interfacial to move
Improve the recrystallization temperature of steel plate.A certain amount of Nb, which is added, can realize two-phase control rolling, non-recrystallization zone lower temperature rolling with
Dislocation density inside austenite is improved, forms the tissue of refinement in subsequent cooling procedure.Nb be realize non-recrystallization rolling,
Obtain the most effective element of final fine grained texture.Nb content is higher to form coarseer NbC precipitation in drawing process, from
And reduce the low-temperature impact work of steel plate.Therefore, the present invention in be added 0.015~0.050wt%Nb with control steel plate microstructure and
Mechanical property.
Al:Al element forms tiny AlN at high temperature and is precipitated, and inhibits austenite grain in heating of plate blank austenitizing
It grows up, achievees the purpose that austenite refinement crystal grain, improves the toughness of steel at low temperature.Al content is excessively high to will lead to biggish Al's
Oxide is formed, and the low temperature impact properties and detection capability of steel plate are reduced.Therefore, it is added 0.02~0.07wt%'s in the present invention
Al refines crystal grain, to improve the toughness of steel plate and guarantee its welding performance.
P, S, O, N: the objectionable impurities elements in steel can significantly reduce the plasticity and toughness and welding performance of steel, therefore Ying Jinke
The above-mentioned impurity content of reduction of energy.
It is that optimization C, Mn and other constituent contents, the present invention set the relationship between C+Mn and other elements to guarantee to adopt
Excellent performance is obtained with suitable composition proportion.Alloyingequivalent (AEQ) considers the condition in appropriate carbon equivalent (CEV)
Under, different-alloy element and its influence to interact to obdurability.Constant term before alloying element is with the alloying element to strong
The influence of toughness is related.Alloyingequivalent considers influence of the compound addition of Nb, V, Mo and Ti to mechanical property of steel plate simultaneously.Together
When, alloyingequivalent is too low, can not produce the steel plate for meeting mechanical property requirements, and it is excessively high, it will lead to carbon equivalent raising, welding
Penalty.
Know the present invention carbon content (0.08% to 0.15wt%) more moderate using relatively other patents, this carbon content was both
Be not it is very low nor very high, can both meet the requirement of steel making working procedure, also can guarantee the subsequent requirement to welding performance of steel plate.Add
The Ca and S content entered guarantees Ca/S=0.5~2.0, makes the complete nodularization of sulfide or approximate spindle, improves the lateral punching of steel plate
Hit performance and cold-bending property.When V, Mo, Ti and other alloying elements in steel are added simultaneously, can not simultaneously close to the upper limit or under
Limit, the purpose for the arrangement is that proof strength and carbon equivalent.To the suitable control of element described above, it is therefore intended that with lower conjunction
Golden cost, accurate composition proportion, simple steel-making, rolling and cooling technique obtain steel plate (material) preferable mechanics, welding etc.
Comprehensive performance.
Composition quality percentage composition as described above and its producer for bending the hot rolled steel plate (volume) that limit intensity is 900MPa grades
Method includes following programs.
Smelt: to blast-melted carry out desulfurization pretreatment, it is compound that blast-melted through desulfurization pretreatment is blended into oxygen top bottom
(such as 210t grades) of converter smelting, for smelting molten steel through Argon, vacuum and after adding calcium heat treatment, ladle chemistry is (i.e. qualified
The mass percentage of each metallurgy element in molten steel) it is identical to the chemical component of finished product material, molten steel is after LF+RH+ Calcium treatment
The steel billet that molten steel send conticaster to be casting continuously to form required cross dimensions, steel billet is with a thickness of 230mm.
Steel billet is sent into soaking pit (or heating furnace) heating, after heating steel billet is to 1150 DEG C~1300 DEG C soaking time >=
15min, such heating temperature and soaking time can be such that the austenite structure of steel billet homogenizes, and can also make Nb, V in steel billet
It is sufficiently dissolved with the carbide of Ti etc., and TiN also has part and melts to prevent growing up for original austenite grains.
Steel billet after heating is rolled: roughing, 5~7 passage of roughing, the single track of roughing mill are carried out to the steel billet of heating
Secondary reduction ratio >=15%, the total reduction of roughing steel billet are 70~85%.Steel billet becomes intermediate base, the centre after roughing after roughing
Base enters finishing tandem rolling unit finish rolling, and intermediate base entry temperature at finishing control is between 1000~1100 DEG C, the single machine of finishing tandem rolling unit
Frame reduction ratio >=10%, intermediate base are 75~97% in the total reduction of finishing tandem rolling unit.
In the second stage of rolling its finishing temperature control between 820~900 DEG C, in this operation of rolling, austenite
It does not recrystallize, and forms the austenite elongated, there are a large amount of deformation band, niobium, vanadium and titaniums in the austenite crystal of elongation
Being precipitated Deng solid solution atom due to deformation induced is carbide and carbonitride.After Unhydrated cement finish to gauge, the tissue of steel is
The austenite structure of deformation.Steel plate thickness after finishing tandem rolling unit finish rolling is 1.2~10.0mm.
Steel plate of the steel billet after finish to gauge carries out ultra-rapid cooling with 100~300 DEG C/S of cooling velocity, with 10~25 DEG C/s layers
Steel plate is cooled to 560~660 DEG C by the cooling method of stream.Cold steel plate is rolled into coil of strip with 560~660 DEG C eventually.If final cooling temperature
When lower than 560 DEG C, microalloy element is precipitated slowly, and amount of precipitation is smaller, and precipitation enhancement is smaller, and intensity can be not achieved.Simultaneously
Temperature is too low also to generate a large amount of bainite structure, be unfavorable for the plasticity of steel plate；If final cooling temperature is higher than 660 DEG C, it is precipitated
The size of phase particle can be obvious thicker, and the tissue of ferrite matrix also can be coarse, and intensity can also be not achieved.
Coil of strip after rolling carries out slow cooling, the case where to ensure the disperse educt of carbide and improve plate shape and internal stress.
Steel plate (volume) transverse and longitudinal yield strength >=900MPa obtained through production technology as above, transverse and longitudinal elongation >=15%,
Transverse and longitudinal Charpy-V impact power AKv (- 40 DEG C) >=27J.The steel plate of 1.2~10.0mm thickness is widely used in lightweight body of tipper carriage
And structural member, there is good welding performance and buckling performance.
Claims (1)
1. a kind of production technology of yield strength 900MPa level hot rolled steel plate, the chemical component of steel C in terms of mass percentage:
0.08~0.15, Mo:0.20~0.5, V:0.10~0.20, Ti:0.10~0.20, Si:0.10~0.40, Mn:1.30~
2.00, P≤0.015, S≤0.005, Nb:0.015~0.050, Al:0.02~0.07, surplus be Fe and it is other inevitably
Impurity, carbon equivalent ce V≤0.55 of steel；It is characterized in that: by converter smelting through LF station Argon and RH vacuum and plus Calcium treatment
Qualified molten steel steel billet is casting continuously to form by conticaster, steel billet is with a thickness of 230mm；
Steel billet is sent into heating furnace or soaking pit and is heated, soaking time is more than or equal at 1150~1300 DEG C of heating temperature
15min；
The roughing on roughing mill the steel billet after heating, total reduction of the steel billet on roughing mill are 70~85%, and steel billet is rolled into
Intermediate base；
Intermediate base enters finishing tandem rolling unit finish rolling, and the entry temperature at finishing that intermediate base enters finishing tandem rolling unit is 1000~1100 DEG C, essence
Rolling finishing temperature is 820~900 DEG C；Total reduction of the intermediate base on finishing tandem rolling unit is 75~97%, and intermediate base is through finishing tandem rolling
Steel plate thickness after unit finish rolling is 1.2~10.0mm；
Steel plate after finish rolling carries out ultra-rapid cooling with 100~300 DEG C/s of cooling velocity, thereafter with 10~25 DEG C/s section cooling
Mode steel plate is cooled to 560~600 DEG C, cold steel plate coils into coil of strip, slow cooling with 560~600 DEG C eventually.
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| CN111440991B (en) * | 2020-04-07 | 2021-10-08 | 湖南华菱涟源钢铁有限公司 | Hot rolled steel plate with yield strength of 800MPa and manufacturing method thereof |
| CN113106350B (en) * | 2021-04-18 | 2023-10-20 | 武汉轻工大学 | Hot-rolled titanium-containing high-strength steel and temperature parameter linkage rolling control method thereof |
| CN113789475B (en) * | 2021-09-14 | 2022-09-16 | 鞍钢股份有限公司 | Method for producing low-alloy hot-rolled steel strip with yield strength of 355MPa at low cost |
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| CN103614629A (en) * | 2013-12-12 | 2014-03-05 | 钢铁研究总院 | 900MPa grade hot rolling non-tempering thin steel sheet and preparation method thereof |
| EP2905348B1 (en) * | 2014-02-07 | 2019-09-04 | ThyssenKrupp Steel Europe AG | High strength flat steel product with bainitic-martensitic structure and method for manufacturing such a flat steel product |
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