CN109055864B - High-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates and its production method - Google Patents

High-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates and its production method Download PDF

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CN109055864B
CN109055864B CN201811165252.4A CN201811165252A CN109055864B CN 109055864 B CN109055864 B CN 109055864B CN 201811165252 A CN201811165252 A CN 201811165252A CN 109055864 B CN109055864 B CN 109055864B
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temperature
cooling
wide
continuous casting
bending bends
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CN109055864A (en
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张帅
任毅
王爽
刘文月
高红
应传涛
徐烽
张坤
姚震
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Angang Steel Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • 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
    • 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
    • C21D8/0236—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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

Abstract

The present invention provides a kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates and its production methods, the ingredient of the steel plate is as follows by weight percentage: C:0.055%~0.080%, Si:0.16%~0.30%, Mn:1.76%~1.95%, Nb:0.051%~0.080%, Ti:0.010%~0.025%, V:0.09%~0.13%, Cr:0.25%~0.45%, Mo:0.20%~0.35%, Ni < 0.25%, Cu < 0.25%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N:0.001%~0.004%, wherein (Mo+Ni+Cr+Cu) : 0.6%~1.0%, CEIIWControl is in 0.50%~0.55%, CEPcmControl is 0.19%~0.23%, and surplus is iron and inevitable impurity, and production method includes molten iron pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling, heat treatment；Microstructure of the present invention is bainite+ferritic complex tissue, and performance meets the requirement of production X90 grades of hot-bending bends of low temperature environment ultra-wide heavy wall.

Description

High-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates and its production method
Technical field
The invention belongs to low-carbon low-alloy steel field more particularly to a kind of low temperature environment hot-bending bends thickness >=22mm, Width > 4300mm X90 grade high-strength, high tenacity, low yield strength ratio hot rolling Wide and Heavy Plates and its production method.
Background technique
In order to improve the transfer efficiency of oil-gas pipeline, discharge pressure and pipe diameter are continuously increased；To take into account conduit running Safety, it is desirable that corresponding oil-gas pipeline steel is to high intensity, heavy wall, the development of big plate width direction.Meanwhile as oil-gas pipeline is built If constantly increasing to the particular surroundings steel for pipe demand such as the active area extension of outlying, cold, geology and low temperature yard, oil The technical indicators such as low-temperature flexibility, the anti-plastic degeneration (high-ductility, low yield strength ratio) of feed channel steel are constantly taken seriously, therefore, simultaneous The product of the features such as tool high intensity, high tenacity, low yield strength ratio, generous specification is the important directions of steel for pipe development.
Hot-bending bends are the important feature parts in oil-gas pipeline, play and change duct orientation, buffering strain and torque and mistake The effects of strong matching protection, use condition is increasingly complex compared with main line pipe, and therefore, the wall thickness of usual hot-bending bends is greater than main line Pipe, moreover, having excellent comprehensive performance.Hot-bending bends of the present invention its thickness >=22mm of Wide and Heavy Plates, width > 4300mm.The feature of heavy wall makes to accelerate cooling effect decrease, the refinement of mid-depth tissue around and the Uniform Control more difficult； To finally significantly increase Properties Control difficulty；Meanwhile with the increase of width, in identical implementation condition and capacity of equipment Under, steel plate rolling deformability is seriously restricted, crystal grain refinement and control difficulty multiplication；Therefore, for low temperature environment thickness For the wide steel for hot-bending bends plate of wall, big plate, how to be obtained in the case where deforming and the techniques such as cooling are restricted good Comprehensive performance and steel-plate shape be the invention solves one of critical issue.In addition, since hot-bending bends are in forming process Heat treatment process is undergone, therefore, steel for hot-bending bends also needs to have good heat resistance, guarantees still to have after being heat-treated good Good comprehensive performance.
The technical indicator that the effective Wide and Heavy Plates of X90 grade low-temp ambient heat simmering and bending are generally configured with includes that horizontal and vertical surrender is strong Degree >=625MPa, horizontal and vertical tensile strength >=740MPa, horizontal and vertical elongation percentage >=20%, horizontal and vertical yield tensile ratio ≤ 0.87, -55 DEG C of horizontal V-shape notch Charpy-V impact power >=120J；Meanwhile the size characteristic wide with heavy wall, big plate.
Currently, there are some researchs to oil-gas transportation bend pipe steel plate both at home and abroad, the related patent in part is had found through retrieval And document, but its documented content and technical solution of the present invention and the product category, ingredient, technique and performance etc. There are notable differences, do not influence creativeness and novelty of the invention.
Existing related invention and document are as follows:
Invention " a kind of preparation method of X90 steel-grade bent pipes and pipe fitting " (publication number: CN102161148A) discloses one kind X90 hot-bending bends and pipe fitting are designed on ingredient, low temperature using high C (0.11%~0.25%), high Si (0.30%~0.50%) Toughness is not high and control is difficult, need to be aided with the elements such as a large amount of Ni, Mo, moreover, the yield tensile ratio of product is high.
Invention " high-ductility steel for hot-bending bends rolling mill practice " (publication number: CN107385340A) discloses X80 grades a kind of The rolling mill practice of steel for hot-bending bends, the X80 grades of steel for hot-bending bends width are less than 2600mm, are unable to satisfy manufacture heavy caliber The requirement of hot-bending bends；The more precious alloys such as Ni:0.60%~0.70%, Mo:0.28%~0.32% are used in ingredient, High production cost；Big pass deformation rate and ultra-rapid cooling are used in technique, harsh requirement are proposed to capacity of equipment, no It is suitable for the production of ultra-wide heavy wall steel for hot-bending bends.
It invents " a kind of preparation method of X100 steel-grade bent and pipe fitting " (publication number: CN102127698A).Provide one X100 hot-bending bends and pipe fitting are planted, is equally set using high C (0.12%~0.20%), high Si (0.30%~0.50%) on ingredient Meter, has that low-temperature flexibility deficiency and yield tensile ratio are high.
Invention " a kind of superhigh intensity bend pipe of low-temperature good toughness " (publication number: JP2005350724 (A)) discloses one X100-X120 grades of bend pipes of kind, equally improve performance by precious alloys such as Ni, Mo and yield tensile ratio is high.
Document " influence of whole process heating and local heating to X90 high-strength steel hot-bending bends tissue and performance " (" welded tube " 6 phases of volume 39 in 2016, Guo Youtian, Chen Zhongjun, Chen Xuan etc.), a kind of X90 hot-bending bends and heat treatment work are mainly described in text Influence of the skill to it, the hot-bending bends ingredient are designed using high Mo (> 0.40%), and cost of alloy is high, moreover, low-temperature flexibility is inclined Low, there are the higher problems of yield tensile ratio.
In conclusion the prior art still has not the low temperature environment research of generous intensity steel for hot-bending bends with a high standard Foot.
Summary of the invention
A kind of low temperature environment steel for hot-bending bends plate is provided it is an object of the invention to overcome the above problem and deficiency, is had There are high intensity, low-temperature flexibility, anti-flow, heat treatment performance to stablize, thickness >=22mm, width > 4300mm X90 grade ultra-wide, thickness Wall, high intensity, high tenacity, low yield strength ratio, high-ductility hot-bending bends Wide and Heavy Plates and its production method.
What the object of the invention was realized in:
Thickness >=22mm of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates of the present invention a kind of, width > 4300mm；Ingredient designs based on low C, low Mn, emphasis Mo, Nb, the Ni valuable using V, Cr element portions or replacing whole Equal elements, guarantee the strength of materials and toughness；Crystal grain is refined in deformation and heat treatment process using elements such as V, Nb and is precipitated strong Change effect, promotes structure refinement and homogenization, improves obdurability, heat resistance and welding performance；It is equipped with and targetedly smelts, adds The production technologies such as heat, rolling, cooling and unique heat treatment obtain have ultra-wide, heavy wall, high intensity, low yield strength ratio, high-ductility and The steel for hot-bending bends plate and ideal microstructure morphology of the excellent overall target such as good low-temperature flexibility.
A kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates, the ingredient of the steel plate is by weight percentage such as Under: C:0.055%~0.080%, Si:0.16%~0.30%, Mn:1.76%~1.95%, Nb:0.051%~ 0.080%, Ti:0.010%~0.025%, V:0.09%~0.13%, Cr:0.25%~0.45%, Mo:0.20%~ 0.35%, Ni < 0.25%, Cu < 0.25%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N: 0.001%~0.004%, wherein (Mo+Ni+Cr+Cu): 0.6%~1.0%, CEIIWControl is in 0.50%~0.55%, CEPcm Control is 0.19%~0.23%, and surplus is iron and inevitable impurity, wherein CEIIW=C+Mn/6+ (Cr+Mo)/5+ (Ni+ Cu)/15；
CEPcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B.
Further, the steel plate microstructure be bainite+ferritic complex tissue, grain size reach 11 grades and with On, wherein ferrite percentage is 10%~30%.
Further, high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates thickness >=22mm, width > 4300mm, Horizontal and vertical yield strength >=630MPa, horizontal and vertical tensile strength >=750MPa, horizontal and vertical elongation percentage >=35%, Horizontal and vertical yield tensile ratio≤0.83, -60 DEG C of side knock function mean value >=220J.
It is as follows that present component designs reason:
C is effective intensified element, is capable of forming interstitial solid solution, improves intensity after harden ability and heat treatment；It can be with Tiny carbide is formed with element interactions such as Nb, V, Ti, is precipitated, plays in slab heating, deformation and steel plate heat treatment process Crystal grain is hindered to grow up, the effect of thinning microstructure；Precipitated phase can hinder dislocation mobile simultaneously, effectively improve intensity, therefore, carbon contains Amount is unsuitable too low；But, it is contemplated that the increase of carbon content is unfavorable to weldability and toughness, especially impaired low temperature toughness, so, Carbon content can not be excessively high, it is considered herein that carbon control is more suitable for 0.055%~0.080%.
Si mainly plays solution strengthening effect in the present invention, improves harden ability, to raising controlled rolling and controlled cooling state and heat treatment State intensity has positive effect；But its too high levels can be such that the plasticity of steel and toughness reduces, and easily cause cold short, optimum range is 0.16%~0.30%.
Mn has solution strengthening effect, and harden ability can be improved, advantageous to intensity after guaranteeing heat treatment；Austria can also be increased Family name's body stability reduces austenite transition temperature, and the phase transformation and crystal grain before inhibiting laminar cooling process are grown up, and plays refinement crystal grain Effect；But the excessively high easy induction segregation of manganese content, deteriorate thick steel sheet structural homogenity and mid-depth toughness and is unfavorable for welding It connects, it is considered herein that being more suitable for 1.76%~1.95% by manganese content control.
Nb has apparent solid solution and precipitation strength effect, and the present invention makes full use of Nb in rolling, accelerates at cooling preceding and heat Precipitation pinning ability during reason, effectively refinement crystal grain improve intensity and improve toughness, meanwhile, Nb can inhibit austenite again Crystallization improves recrystallization rolling temperature, thus, roll-force is effectively reduced, to raising ultra-wide of the present invention, heavy wall hot-bending bends With the rolling pass deformation rate of steel plate, reaches expected fine grain effect and play a positive role；In addition, Nb can also reduce thick-walled pipe Line steel when rolling thickness direction temperature difference due to the mixed crystal problem that generates, still, Nb too high levels can make production cost obvious Increase, moreover, precipitate can be promoted to grow up, is unfavorable for playing invigoration effect instead, have an adverse effect to toughness, the present invention recognizes To be more suitable for 0.051%~0.080% by the control of Nb content.
Ti can play nitrogen fixation effect, form the precipitated phase based on TiN, can inhibit the crystal grain of austenite under hot conditions It grows up, is conducive to refine slab and steel plate microstructure, postwelding heat affected area toughness can also be improved；Meanwhile Ti is at high temperature N, C concentration can be reduced by forming precipitated phase, inhibited the precipitations of elements at high temperature such as Nb, V, formed it easily at lower temperatures Tiny precipitated phase, to be more advantageous to raising performance.It is considered herein that more by Ti content control 0.010%~0.025% It is suitable for.
V has solid solution and precipitation effect, and when solid solution can effectively improve intensity；And its Precipitation Temperature is lower than based on Nb, Ti Precipitated phase, tiny precipitation can be formed in conjunction with C, N in rolling, cooling and heat treatment process, especially be heat-treated when have There is post-curing effect, increase resistance to tempering ability, guarantees performance after heat treatment.Emphasis of the present invention uses the both the above characteristic of V It is effectively improved comprehensive performance.But V content is excessively high to will affect steel plate and hot-zone toughness, and therefore, the present invention controls V content 0.09%~0.13%.
Cr can improve stabilization of austenite and harden ability, reduce austenite transition temperature, refine crystal grain, after guaranteeing heat treatment Performance plays good action to improving thick steel sheet intensity and improving thickness direction structural homogenity；There are also solution strengthening works by Cr With advantageous to proof strength；Meanwhile Cr can reduce the diffusivity of C, improve heat-treatability stabilizability, promote Nb, V analysis The refinement of phase out；Moreover, Cr element economy is high, the expensive alloying elements such as Mo, Ni can be partially substituted；The present invention makes full use of The above characteristic of Cr effectively improves the comprehensive performance of product；But Cr too high levels are unfavorable to weldability, and plasticity also has deterioration Trend, so, Cr content control 0.25%~0.45% is advisable.
Mo can increase stabilization of austenite, hence it is evident that improve harden ability, cryo tissue transformation in promotion increases intensity, also The structure property of steel plate and the area HAZ can be optimized, still, the excessively high one side of molybdenum content will increase cost, on the other hand, will increase M/A in tissue etc. hardens phase, therefore its content should be controlled 0.20%~0.35% by reducing toughness.
Ni plays solution strengthening effect, is conducive to improve low-temperature flexibility；Middle temperature transformation can also be promoted to organize the formation of, reduced The limitation of thick steel plates cooling rate；But nickel price is higher, and therefore, its content is controlled to be advisable < 0.25%.
Cu can play solution strengthening effect, meanwhile, it is capable to reduce the diffusivity of C, improve heat-treatability stabilizability, Cu Corrosion resistance can also be improved, but Cu too high levels easily induce crackle, damage weldability, it is considered herein that by copper content control < 0.25% is more suitable for.
Al is deoxidant element, also has stronger combination trend with N, and AlN can improve welding hot-zone toughness；But Al content The excessively high increase that can promote field trash, the present invention control Al 0.010%~0.035%.
P, S is objectionable impurities elements in the present invention, and the lower content the better；Wherein, P has low-temperature flexibility apparent unfavorable It influencing, P control can be promoted the generation of field trash in the increase of≤0.010%, S content and grown up by the present invention, deteriorate performance, because This, S≤0.002%.
N can form precipitate in conjunction with the elements such as Nb, V, Ti, play obvious work to inhibiting when heating of plate blank crystal grain to grow up With, meanwhile, precipitation strength effect can be played in rolling, cooling and heat treatment process, therefore, there are certain N to property in steel Can be advantageous, but too high levels can deteriorate the toughness of base material and welding heat affected zone, and content is controlled 0.001%~0.004% It is advisable.
Mo, Ni, Cr, Cu all have invigoration effect, increase stabilization of austenite, are conducive to after improving harden ability and heat treatment Performance, Mo+Ni+Cr+Cu is too low to be unfavorable for performance and microstructure control, and too high levels influence weldability and economy, therefore, The present invention is by (Mo+Ni+Cr+Cu): 0.6%~1.0%.
CEIIW is controlled and is controlled in 0.50%~0.55%, CEPcm 0.19%~0.23% by the present invention, can both be protected The obdurability of steel plate is demonstrate,proved, and can make steel plate that there is suitable solderability.
The two of technical solution of the present invention are to provide a kind of production of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates Method, including molten iron pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling, heat treatment；
(1) continuous casting: the Argon calmness time is no less than 10min before continuous casting after liquid steel refining, continuous casting billet be poured the degree of superheat 15~ 35 DEG C, continuous casting billet pulling rate 0.6m/min-1.0m/min, thickness of strand/finished steel plate thickness control is in 7-14；Blowing before continuous casting Argon calmness can be improved the uniformity of liquid steel temperature and ingredient, be conducive to the floating removal of field trash；It is poured the degree of superheat and continuous casting The control of base pulling rate can effectively reduce slab quality defect；It is thin that compression ratio from continuous casting billet to finished steel plate is conducive to crystal grain Change.
(2) heat: continuous casting billet shove charge after clearing up is heated, using two stages heating method, wherein high-temperature heating section temperature 1210~1240 DEG C, 1200~1230 DEG C of soaking section temperature, high-temperature heating section+soaking zone time is not less than 150min；Continuous casting billet Cleaning can effectively reduce surface defect, and the design of heating process is allowed to mainly for the solid solution of guarantee alloying element in subsequent life Ideal effect is played in production, meanwhile, effectively control Austenite Grain Growth；Heating time can guarantee that heating effect and temperature are equal Even property.
(3) roll: roughing start rolling temperature is 1120~1170 DEG C, and roughing finishing temperature is 1000~1050 DEG C, using cross Vertical rolling mode, wherein axial rolling start temperature is not higher than 1090 DEG C, and the axial rolling stage guarantees that the passage of at least last 2 passages becomes Form quotient is greater than 15% and road minor tick is no more than 15s；Roughing mill speed 1.2m/s-2.0m/s；The rolling temperature of rough rolling step Recrystallize austenite grain with deformation technique, roughing axial rolling latter end can take into account equipment using big pressure and short spacer process Deformation Overlay is preferably played under the premise of ability, rolling load, is promoted austenite to recrystallize, is reached crystal grain refinement Target, the production of ultra-wide thick steel sheet of the present invention preferably, the control of roughing mill speed can promote rolling deformation to thickness The infiltration at center refines mid-depth crystal grain, is conducive to the core structure for improving big wall thickness pipe line steel.
Intermediate temperature control plate blank thickness 3.1t~5.0t, wherein t is finished steel plate thickness, and finish rolling start rolling temperature is 810~900 DEG C, finish rolling finishing temperature is 720~750 DEG C；It on the one hand can guarantee using big intermediate temperature control plate blank thickness and low final rolling temperature Austenite deformation simultaneously accumulates deformation energy, on the other hand, the induction of the tiny precipitated phase of Nb, V can be promoted to be precipitated, pinning crystal boundary with Dislocation increases nucleation site, refines crystal grain；Furthermore tiny ferrite forming core can also be promoted.
(4) cooling: it rolls rear steel plate and carries out acceleration water cooling, start 710~740 DEG C of cooling by water temperature, final cooling temperature 340~ 460 DEG C, 8~20 DEG C/s of cooling by water speed, the cooling by water time is not less than 15s.Since the elements such as Cr, Mn, Mo, Cu can drop Low austenite transition temperature, it is therefore possible to use lower begin to cool temperature, be conducive to crystal grain refinement and tiny precipitate Formation；Moreover, because alloying element improves harden ability, lower cooling velocity and longer cooling time can be used, To increase the cooling uniformity of thick steel sheet thickness direction, steel plate internal stress is reduced, that is, being able to satisfy performance can reduce again Influence to plate shape.
(5) it is heat-treated: when heat treatment, 840~890 DEG C of hardening heat of control, Quenching Soaking Time 0.5min/mm~ 1.0min/mm, quenching can be had using low-temperature heat technique while obtaining polygonal ferrite+austenite complex tissue Effect inhibits growing up for crystal grain；Cooling velocity >=15 DEG C/s is quenched, is cooled to room temperature, polygonal ferrite+bainite, M/A are obtained Hard phase；350~500 DEG C of tempering temperature, tempering insulation time 1.6min/mm~3.0min/mm, promote precipitation strength and tempering Hardening improves yield strength, reduces residual stress, meanwhile, the excessive precipitation of element and growing up for bainite crystal grain are prevented, is protected Demonstrate,prove intensity.
Microstructure is bainite+ferritic complex tissue after steel plate heat treatment, and grain size reaches 11 grades of grades or more, In, for ferrite percentage 10%~30%, steel plate has ultra-wide, heavy wall, high intensity, low yield strength ratio, high-ductility and good Good low-temperature flexibility, meanwhile, weldability and mouldability meet the requirement for making X90 grades of hot-bending bends of ultra-wide heavy wall.
A kind of production method of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates provided by the invention, is intended to obtain Ideal internal soundness, the crystal grain that reduces harmful element and effectively refine steel plate after controlled rolling and controlled cooling while impurity, control analysis Phase out, thus, tissue and structure after refining and controlling heat treatment by tissue heredity and suitable heat treatment process are protected Performance after card heat treatment.
The beneficial effects of the present invention are:
(1) based on low C, low Mn, emphasis is valuable using V, Cr element portions or replacing whole for present component design The elements such as Mo, Nb, Ni, guarantee the strength of materials and toughness；Crystalline substance is refined in deformation and heat treatment process using elements such as V, Nb Grain and precipitation strength effect, promote structure refinement and homogenization, improve obdurability, heat resistance and welding performance；It is equipped with phase therewith The unique production technology answered makes low temperature environment ultra-wide heavy wall steel for hot-bending bends plate obtain ideal heterogeneous microstructure, tiny Crystal grain, excellent comprehensive performance and good profile.
(2) carbon equivalent ce IIW and CEPcm of the present invention is suitable for guaranteeing that material has good intensity and solderability.
(3) refining of the invention, continuous casting process scheme effectively improve slab quality, to improve final products performance.
(4) present invention using unique low temperature low speed it is short interval roll+roll rear low temperature it is long when uniformly control cold+low temperature quenching and Tempering process gives full play to the effects of alloying element reduces phase transition temperature, improves harden ability, fine grain is precipitated and strengthens and tissue The compound matching effect of heredity, multinomial tissue obtains strong plasticity and toughness and matches good product, meanwhile, it increases cooling uniform Property, internal stress and structural stress are reduced, the plate shape of steel plate is effectively controlled.
(5) thickness >=22mm, width of a kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates of the present invention > 4300mm, horizontal and vertical yield strength >=630MPa, horizontal and vertical tensile strength >=750MPa, horizontal and vertical elongation percentage >=35%, horizontal and vertical yield tensile ratio≤0.83, -60 DEG C of side knock function mean value >=220J, microstructure is bainite+iron element The complex tissue of body, wherein for polygonal ferrite percent by volume 10%~30%, grain size reaches 11 grades or more, meets Make the requirement of X90 grades of hot-bending bends of low temperature environment ultra-wide heavy wall.
Detailed description of the invention
Fig. 1 is the microscopic structure metallographic microscope of the embodiment of the present invention 2.
Specific embodiment
Below by embodiment, the present invention is further illustrated.
The embodiment of the present invention according to the component proportion of technical solution, carry out molten iron pretreatment, converter smelting, external refining, Continuous casting, heating, rolling, cooling, heat treatment.
(1) continuous casting: the Argon calmness time is no less than 10min before continuous casting after liquid steel refining, continuous casting billet be poured the degree of superheat 15~ 35 DEG C, continuous casting billet pulling rate 0.6m/min-1.0m/min, thickness of strand/finished steel plate thickness control is in 7-14；
(2) heat: continuous casting billet shove charge after clearing up is heated, using two stages heating method, wherein high-temperature heating section temperature 1210~1240 DEG C, 1200~1230 DEG C of soaking section temperature, high-temperature heating section+soaking zone time is not less than 150min；
(3) roll: roughing start rolling temperature is 1120~1170 DEG C, and roughing finishing temperature is 1000~1050 DEG C, using cross Vertical rolling mode, wherein axial rolling start temperature is not higher than 1090 DEG C, and the axial rolling stage guarantees that the passage of at least last 2 passages becomes Form quotient is greater than 15% and road minor tick is no more than 15s；Roughing mill speed 1.2m/s-2.0m/s；
Intermediate temperature control plate blank thickness 3.1t~5.0t, wherein t is finished steel plate thickness, and finish rolling start rolling temperature is 810~900 DEG C, finish rolling finishing temperature is 720~750 DEG C；
(4) cooling: it rolls rear steel plate and carries out acceleration water cooling, start 710~740 DEG C of cooling by water temperature, final cooling temperature 340~ 460 DEG C, 8~20 DEG C/s of cooling by water speed, the cooling by water time is not less than 15s；
(5) it is heat-treated: 840~890 DEG C of hardening heat, Quenching Soaking Time 0.5min/mm~1.0min/mm, quenching cold But speed >=15 DEG C/s, is cooled to room temperature；350~500 DEG C of tempering temperature, tempering insulation time 1.6min/mm~3.0min/ mm。
The ingredient of steel of the embodiment of the present invention is shown in Table 1.The smelting continuous casting process and heating of plate blank parameter of steel of the embodiment of the present invention It is shown in Table 2.The roughing technique of steel of the embodiment of the present invention is shown in Table 3.The finish rolling of steel of the embodiment of the present invention and cooling technique are shown in Table 4.This hair Bright embodiment Heat-Treatment of Steel technique is shown in Table 5.The performance table 6 of steel of the embodiment of the present invention.The microstructure of steel of the embodiment of the present invention It is shown in Table 7.
The ingredient (wt%) of 1 steel of the embodiment of the present invention of table
Embodiment 1 2 3 4 5 6
C 0.071 0.065 0.058 0.066 0.056 0.062
Si 0.22 0.26 0.18 0.25 0.27 0.20
Mn 1.79 1.91 1.76 1.82 1.87 1.77
P 0.008 0.007 0.008 0.006 0.005 0.006
S 0.0013 0.0017 0.0014 0.0013 0.0016 0.0014
Nb 0.065 0.076 0.058 0.064 0.073 0.055
Ti 0.017 0.021 0.013 0.015 0.012 0.013
Cr 0.31 0.40 0.38 0.28 0.34 0.42
V 0.09 0.10 0.12 0.09 0.10 0.11
Mo 0.24 0.22 0.31 0.32 0.28 0.22
Ni 0.13 0 0.16 0 0.21 0.12
Cu 0 0 0.14 0.08 0 0.19
Al 0.030 0.021 0.027 0.019 0.033 0.031
N 0.0031 0.0018 0.0025 0.0018 0.0026 0.0036
CEIIW 0.506 0.527 0.533 0.513 0.526 0.528
CEPcm 0.211 0.214 0.213 0.214 0.208 0.215
The smelting continuous casting and heating of plate blank technological parameter of 2 steel of the embodiment of the present invention of table
The roughing technique of 3 steel of the embodiment of the present invention of table
The finish rolling and cooling technique of 4 steel of the embodiment of the present invention of table
5 Heat-Treatment of Steel technique of the embodiment of the present invention of table
Embodiment Hardening heat, DEG C Quenching Soaking Time, min/mm Tempering temperature, DEG C Tempering insulation time, min/mm
1 860 0.8 380 2.9
2 840 0.9 410 2.4
3 880 0.6 440 1.7
4 860 0.8 370 1.9
5 840 0.9 390 1.6
6 860 0.7 360 2.1
The performance of 6 steel of the embodiment of the present invention of table
Note: tensile sample is through thickness rectangular specimen, the wide 38.1mm of parallel testing section plate；Impact specimen is having a size of 10*55* 55mm
The microstructure of 7 steel of the embodiment of the present invention of table
From the foregoing, it will be observed that using high-strength tenacity low yield strength ratio hot-bending bends made from technical solution disclosed by the invention with generous Thickness >=22mm, the width > 4300mm of steel plate, horizontal and vertical yield strength >=630MPa, horizontal and vertical tensile strength >= 750MPa, horizontal and vertical elongation percentage >=35%, horizontal and vertical yield tensile ratio≤0.83, -60 DEG C of side knock function mean values >= 220J, microstructure is based on bainite+ferritic complex tissue, wherein polygonal ferrite percent by volume 10%~ 30%, grain size reaches 11 grades or more, meets the requirement of production X90 grades of hot-bending bends of low temperature environment ultra-wide heavy wall.
In order to state the present invention, explanation appropriately and is being sufficiently carried out to the present invention by embodiment among the above, it is above Embodiment is merely to illustrate the present invention, and not limitation of the present invention, those of ordinary skill in related technical field, not In the case where being detached from the spirit and scope of the present invention, it can also make a variety of changes and modification, made any modification are equally replaced It changes, improve, should all be included in the protection scope of the present invention, scope of patent protection of the invention should be limited by claim It is fixed.

Claims (3)

1. a kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates, which is characterized in that the ingredient of the steel plate by weight hundred Divide as follows than counting: C:0.056%~0.080%, Si:0.16%~0.30%, Mn:1.76%~1.95%, Nb:0.051% ~0.080%, Ti:0.010%~0.025%, V:0.09%~0.13%, Cr:0.25%~0.45%, Mo:0.20%~ 0.35%, Ni < 0.25%, Cu < 0.25%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N: 0.001%~0.004%, wherein (Mo+Ni+Cr+Cu): 0.62%~1.0%, CEIIWControl 0.50%~0.55%, CEPcmControl is 0.19%~0.23%, and surplus is iron and inevitable impurity, wherein CEIIW=C+Mn/6+ (Cr+Mo)/5+ (Ni+Cu)/15；CEPcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B；The high-strength tenacity is low to bend by force The production method of the effective Wide and Heavy Plates of specific heat simmering and bending, including molten iron pretreatment, converter smelting, external refining, continuous casting, heat, roll System, cooling, heat treatment；
(1) continuous casting: the Argon calmness time is no less than 10min before continuous casting after liquid steel refining, and continuous casting billet is poured 15~35 DEG C of the degree of superheat, Continuous casting billet pulling rate 0.6m/min-1.0m/min, thickness of strand/finished steel plate thickness control is in 7-14；
(2) heat: continuous casting billet shove charge after clearing up is heated, using two stages heating method, wherein high-temperature heating section temperature 1210 ~1240 DEG C, 1201~1230 DEG C of soaking section temperature, high-temperature heating section+soaking zone time is not less than 150min；
(3) roll: roughing start rolling temperature is 1120~1170 DEG C, and roughing finishing temperature is 1000~1050 DEG C, is rolled using transverse and longitudinal Mode processed, wherein axial rolling start temperature is not higher than 1090 DEG C, and the axial rolling stage guarantees the pass deformation rate of at least last 2 passages Greater than 15% and road minor tick is no more than 15s；Roughing mill speed 1.2m/s-2.0m/s；
Intermediate temperature control plate blank thickness 3.1t~5.0t, wherein t is finished steel plate thickness, and finish rolling start rolling temperature is 810~900 DEG C, essence Rolling finishing temperature is 720~750 DEG C；
(4) cooling: to roll rear steel plate and carry out acceleration water cooling, start 710~740 DEG C of cooling by water temperature, final cooling temperature 340~460 DEG C, 8~20 DEG C/s of cooling by water speed, the cooling by water time is not less than 15s；
(5) it is heat-treated: 840~890 DEG C of hardening heat, Quenching Soaking Time 0.5min/mm~1.0min/mm, quenching cooling speed >=15 DEG C/s is spent, is cooled to room temperature；350~440 DEG C of tempering temperature, tempering insulation time 1.6min/mm~3.0min/mm.
2. a kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates according to claim 1, which is characterized in that institute Stating steel plate microstructure is bainite+ferritic complex tissue, and grain size reaches 11 grades or more, wherein ferrite Percentage is 10%~30%.
3. a kind of high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates according to claim 1, which is characterized in that institute State high-strength tenacity low yield strength ratio hot-bending bends Wide and Heavy Plates thickness >=22mm, width > 4300mm, horizontal and vertical yield strength >=630MPa, horizontal and vertical tensile strength >=750MPa, horizontal and vertical elongation percentage >=35%, horizontal and vertical yield tensile ratio≤ 0.83, -60 DEG C of side knock function mean value >=220J.
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