CN107460413A - A kind of preparation method and application of 550MPa levels Ultra-fine Grained high-strength weathering steel - Google Patents
A kind of preparation method and application of 550MPa levels Ultra-fine Grained high-strength weathering steel Download PDFInfo
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- CN107460413A CN107460413A CN201710703326.4A CN201710703326A CN107460413A CN 107460413 A CN107460413 A CN 107460413A CN 201710703326 A CN201710703326 A CN 201710703326A CN 107460413 A CN107460413 A CN 107460413A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- 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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—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
Abstract
The present invention relates to a kind of preparation method and application of 550MPa levels Ultra-fine Grained high-strength weathering steel, the preparation method is directly entered M frame roughing mills including continuous casting billet under high pulling rate, (50%~60%) roughing is continuously depressed greatly by M passages, austenite crystal significantly refines, after roughing, middle base quickly heats up to temperature needed for finish rolling entrance by induction heater, form reverse temperature field simultaneously, then in turn through finish rolling group, section cooling, coiling machine, the tissue signature of surface and core relatively slightly, thinner at 1/4 thickness is ultimately formed.Finish rolling and roughing are full endless rolling in production process.The present invention can obtain Ultra-fine Grained high-strength weathering hot rolled strip of the weatherability equivalent to corten A, realize " with Bao Daihou " and " with hot Dai Leng " effect, while making Vehicle mass reduction, improve Automobile Plate service life, production efficiency is improved, reduces production cost, while reduce energy consumption, discharge is reduced, realizes resource-conserving, environmentally friendly production.Belong to metallurgical technology field.
Description
Technical field
The invention belongs to metallurgical technology field.More particularly to a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel
And application.
Background technology
Weathering steel is by adding a kind of low-alloy steel, major alloy made of a certain amount of alloying element in ordinary steel
Composition is the elements such as Cu, P, Cr, Ni.Tough, modeling with high-quality steel are prolonged, are molded, welding, abrasion, high temperature, the spy such as antifatigue
Property；Weatherability is 2~8 times of straight carbon steel, and coating is 1.5~10 times of straight carbon steel.Meanwhile it has antirust, resist component
The features such as corrosion is lengthened the life, consumption reduction is thinned, and saving of labor saves.Compared to other lightweighting materials such as aluminium alloy, plastics, although high-strength steel
Have the advantages that cost is low, intensity is high, impact resistance is good, but its atmospheric corrosion resistance is relatively poor.In recent years, with China
The fast development of national economy, it is increasing to the demand of the railway high-strength weathering steel of passenger and freight, in order to improve transport
Efficiency, mitigate carriage weight, save cost of transportation and extend compartment service life, it is desirable to manufacture the intensity of compartment weathering steel
Rank and corrosion resisting property improve constantly.Therefore, considering cost, processing mode, recoverable etc., exploitation it is high-strength,
The combination property such as ultra-thin, weather-proof is trend of the times in the high-strength steel of one.
High-strength weathering steel refers to Rel (yield strength) >=400MPa weathering steel, and this kind of steel is in special container and goods
Had broad application prospects in the manufacture of car railway carriage.Because high-strength weathering steel is requiring high corrosion proof while is requiring high
Intensity rank and preferable forming property and welding performance, therefore to metallurgical technology process and equipment controlled level requirement very
The superhigh intensity weather-resistant steel plate of height, especially yield strength 550MPa, only very few country can produce at present.Japanese, Germany,
South Korea, Sweden etc. have produced high-strength weathering steel more than yield strength 400MPa using traditional process, for railcar
With the production of boxcar.By contrast, China starts to walk in light weight material in automobile, especially high-strength weathering steel research and development with application
Later, such as in the market using more box semitrailer carriage steel based on Q235 and Q345, not only low intensity, weather-proof
Performance is also poor.But, with the continuous intensification that some domestic iron and steel enterprises are recognized automobile high-strength weathering steel, had started in recent years
Set about the exploitation and popularization of high-strength weathering Automobile Plate, the research and development of the weather-proof sheet billet of yield strength 550MPa grade high-strengths become respectively
Big steel mill and associated vehicle manufacturer focus of attention.
At present, the industrial production of the high-strength hot-strip of yield strength 550MPa levels is more using the rolling of sheet billet list base or half nothing
Head rolling mill practice, traditional mode of production process are：→ acid is batched in continuous casting → strand reheating → roughing → finish rolling → section cooling →
Wash → cold rolling → annealing.Using the rolling bottom formula stove or induction heater pair of 200-280m length as this rolling mill practice is previous in roughing
Continuous casting billet is heated, and carries out cocurrent using rolling bottom formula.
Traditional rolling mill practice has the increase of production line length, equipment composition complexity, Operation and Maintenance cost height, energy consumption height etc.
Shortcoming.And because production line is long (more than 400m), essence is pricked inlet temperature and can not accurately controlled, and causes the final structure property of product
It is unstable.In addition, under the hot rolling surface quality and product specification of this single base rolling of tradition or semi-endless rolled production do not reach
Swim user and require that the hot rolled plate after pickling generally requires could supply by follow-up cold rolling, annealing process so that production process is numerous
Miscellaneous, production efficiency reduces, production cost increase.
The content of the invention
To solve the above problems, the present invention provides a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel, it has
Have the advantages that to shorten technological process, fining austenite grains and the mechanical property for improving product.In addition, this method can give birth in ESP
Applied in producing line.
The present invention is achieved by the following technical solutions：
A kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel, the preparation method include continuous casting step, roughing
Step, finish rolling step, section cooling step and batch step；
The preparation method is successively by continuous casting step, roughing step, finish rolling step, section cooling step by initial feed
It is rapid and after batching step, obtain final finished sheet billet；
The roughing step includes：It is thick that the continuous casting billet that the continuous casting step obtains under high pulling rate is directly over M frames
Milling train group carries out the big pressure of M passages, obtains middle base；
The roughing step and finish rolling step are full endless rolling.
Further, the high pulling rate is 3-7m/min.
Further, the M is positive integer, and M is not less than 3.
Further, the drafts of the big pressure of single pass of the big pressure of M passages is 50%-60%.
Further, the continuous casting billet that the continuous casting step obtains directly carries out roughing to it, without thick in traditional handicraft
To the reheating link of strand before rolling, technological process is shortened, higher single machine yield is obtained while energy consumption is reduced.
Further, drafts big at high temperature in the roughing step causes original austenite grain significantly to refine,
Organization foundation is provided for final uniform tiny ferritic structure.
Further, the preparation method also includes middle base processing step；
The middle base processing step is after the roughing step；
The middle base processing step includes：The middle base that the roughing step is obtained is placed in induction heater and quickly added
Heat is to temperature T1, the middle base after being handled.
Further, the middle base processing step also includes：The middle base that the roughing step is obtained passes through successively
Rocking shears, push away useless roller-way, after rotating hub is cut, then carry out sensing heating.
Further, the temperature T1For the entry temperature at finishing of the middle base after the processing.
Further, the temperature T1For 1100-1200 DEG C.
Further, the middle base processing step accurately controls middle base essence and pricks inlet temperature T1, meet to prick temperature eventually
Degree requires；Meanwhile middle base surface temperature is high after sensing heating, core temperature is low, and this reverse temperature field is slab thickness side
Temperature basis is provided to special tissue signature's (surface and core are thicker, thinner at 1/4 thickness).
Further, the thickness of strand is 80-100mm.
Further, pulling rate is 3-7m/min in the continuous casting step.
Further, the molten steel flow in the continuous casting step into casting machine is 4-6.5t/min.
Further, the finish rolling step includes：N is carried out to the middle base after the processing using N frames mm finishing mill unit
Passage is depressed, and obtains sheet billet.
Further, the N is positive integer, and N is not less than 5.
Further, the thickness specification of the sheet billet be 1.2-1.4mm, width specifications 1500mm.
Further, finishing temperature is 800-850 DEG C in the finish rolling step.
Further, the drafts of the single pass pressure of the N passages pressure is 30%-40%, and it can make austenite
Crystal grain further refines, in addition, finishing temperature is relatively low to ensure that austenite is not rolling in crystal region, increases dislocation density, increases
Large deformation energy storage, improve the forming core speed of deformation induced ferrite and deformation-induced precipitation in follow-up cooling procedure.
Further, the section cooling step includes：The sheet billet that the finish rolling step is obtained, by equipped with a high position
The laminar cooling system of water tank, takes the intensive type of cooling of leading portion, and the sheet billet is cooled into coiling temperature T2, cooled down
Sheet billet.
Further, the coiling temperature T2For 620-660 DEG C.
Further, in the section cooling step, cooling velocity is more than 50%.
Further, the section cooling step uses the intensive type of cooling of leading portion, and cooling velocity is more than 50%；This
Kind of leading portion is intensive and the faster type of cooling, can make build up, and then improve the mechanical property of the final finished sheet billet.
Further, the step of batching includes：The cooling sheet billet that the section cooling step is obtained carries out bundling
Coiling process afterwards, coiling temperature T when batching2, room temperature is air-cooled to after batching, obtains the final finished sheet billet.
Further, the bundling process carries out bundling using high-speed flying shear.
Further, the coiling process is batched using coiling machine.
Further, the preparation method also includes dephosphorization step, and the dephosphorization step is placed in before the finish rolling step.
Further, the dephosphorization step includes：After the processing obtained using high pressure dephosphorization case to middle base processing step
Middle base carry out dephosphorization.
A kind of application of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel on ESP production lines.
Further, the ESP production lines total length is 180-210m.
Further, the ESP production lines total length is 190m.
Further, each portion of ESP production lines is directly connected to by strip.
Further, the production process of the ESP production lines does not have threading and throws steel.
Further, the ESP production lines continuous casting step is 6-10min to the time used in step is batched.
Further, the ESP production lines continuous casting step is 7min to the time used in step is batched.
Further, the ESP production lines can low cost, low energy consumption, it is compact, efficiently produce the high property of dimensional accuracy
The excellent hot rolled thin strip coil of strip of energy.
A kind of application of the preparation method of described 550MPa levels Ultra-fine Grained high-strength weathering steel on ESP production lines, is started
The big Reduction Technology of roughing and middle base induction heating technique are employed to property, produces grain size number up to 13.0~13.5 grades
Ultra-fine Grained high-strength weathering steel.
Further, the chemical composition of the initial feed includes：Carbon, silicon, aluminium, manganese, copper, titanium, niobium, nickel, chromium, phosphorus, sulphur,
Nitrogen and iron；
The mass fraction of each chemical composition of initial feed is：0.02-0.06% carbon, 0.1-0.4% silicon, 1.0-
1.7% manganese, 0.01-0.05% aluminium, 0.1-0.4% copper, titanium 0.04-0.08%, niobium 0.02-0.05%, nickel 0.1-0.3%, chromium
0.3-0.7%, phosphorus≤0.015%, sulphur≤0.003%, nitrogen≤0.004%, surplus are iron.
Further, the thickness specification of the final finished sheet billet be 1.2-1.4mm, width specifications 1500mm, group
Single-phase ferrite is woven to, mean grain size reaches 13.0-13.5 levels, and shows surface and core crystal grain is thicker, crystal grain at 1/4 thickness
Thinner tissue characteristic.At room temperature, precipitate mainly includes TiC, NbC and a small amount of (Ti, Nb) N, and size is 500~200nm
Between.In atmospheric environment, the weather-proof steel surface forms double-deck corrosion products film, and internal layer is mainly Cr, Ni oxide, outside
Layer is mainly Fe oxide and CuS.
The mass fraction selection 0.02-0.06% of carbon (C) in the initial feed, it is therefore an objective to make casting process avoid peritectoid
Reaction, prevents that continuous casting billet solidification processing amount of contraction is big, and crackle even bleed-out is formed in follow-up roughing.Meanwhile too high C content
The plasticity of steel can also declined, seriously affects the cold formability energy and weldability of steel.
The mass fraction selection 0.1-0.4% of silicon (Si) in the initial feed, it is played as ferrite former
The effect of solution strengthening, in addition, low silicon is designed with beneficial to weldability, cold formability and the antifatigue toughness for improving steel.
The mass fraction selection 1.0-1.7% of manganese (Mn) in the initial feed, on the one hand, manganese can pass through solution strengthening
Act on the intensity of steel during ensureing low-carbon design；On the other hand, manganese can expand γ areas, reduce γ → α phase transition temperatures, promote former material
Material obtains low-temperature transformation tissue in quasi-polygonal ferrite or acicular ferrite structure etc., so as to improve matrix strength.But mistake
High Mn contents can influence cold stamping and the welding performance of steel, while cause rolling load to increase.
The mass fraction of titanium (Ti) and niobium (Nb) selects 0.04-0.08% and 0.02- respectively in the initial feed
0.05%, micro titanium (Ti), niobium (Nb) are added mainly using the precipitation strength of carbonitride particle, to ensure the strong of steel
Degree.
In CSP process, too high Ti contents, which easily cause strand and side occur in the operation of rolling, to be split and makes
It is unstable to obtain mechanical property, and too high Nb contents easily cause mixed crystal.Due to the content of C, N in steel relatively low, too high Ti, Nb
Content can not play enough invigoration effects, can increase the cost of steel on the contrary.Can in addition, adding micro Ti, Nb element in steel
Improve the recrystallization temperature of steel so that steel can be completed to obtain the deformation for storing large deformation energy while rolling at a higher temperature
Austenite structure, and then tiny phase-change organization is obtained, the intensity of steel is improved by refined crystalline strengthening.
Chromium (Cr), nickel (Ni), the mass fraction of copper (Cu) select 0.3-0.7%, 0.1- respectively in the initial feed
0.3%th, 0.1-0.4%, chromium (Cr) and nickel (Ni) are primarily used to form the internal layer corrosion products film of densification, and passivation is produced to matrix
Effect, copper (Cu) plug the hole in dimple shape rusty scale, prevented mainly with CuS formal distribution in outer layer corrosion products film
The infiltration of etchant gas inner layer.Passivation and outer layer to matrix form corrosion products film and prevent etchant gas inner layer
Both synergies of infiltration improve the weatherability of steel to reduce the corrosion rate of matrix.
The mass fraction selection≤0.015% of phosphorus (P) in the initial feed, phosphorus (P) easily forms serious segregated zone, just
The addition of phosphorus (P) can greatly improve the rank of banded structure in beginning raw material.
The mass fraction selection≤0.003% of sulphur (S) in the initial feed, due to initial feed from high Mn into setting up separately
Meter, S form MnS field trashes easily in steel, segregation phenomena occur.
The mass fraction selection≤0.004% of nitrogen (N) in the initial feed, nitrogen (N) are easily thick in high-temperature region generation with Ti
Big liquation TiN, makes the Ti in steel lose precipitating reinforcing effect.
Therefore, the P, S controlled in weathering steel, the N content of should trying one's best are in relatively low scope.
The finished sheet base of obtained cooling after the section cooling is by bundling and batches, and is slowly cooled to after batching
Room temperature.Coordinate the mode of slow cooling after high temperature coiling, Ti, Nb nano-sized carbonitride can be made fully to separate out, pass through strong analysis
Go out the mechanical property that invigoration effect further improves steel.
In atmospheric environment, the surface of the weathering steel forms double-deck corrosion products film；The internal layer of the weathering steel is main
For Cr, Ni oxide, both form the corrosion products film of densification, generate passivation to matrix, improve the anti-corrosion of matrix
Performance；The outer layer of the weathering steel is mainly Fe oxide and CuS, wherein hole of the CuS integrated distributions in dimple shape rusty scale
In, outer layer corrosion products film is plugged, prevents the infiltration of air inner layer, so as to reduce the corrosion rate of matrix.Therefore,
This anti-corrosion mechanism of bilayer that weathering steel has so that the average corrosion rate in atmospheric environment of the weather-proof steel grade is less than
0.08g/(m2·h)。
Application of the preparation method on the ESP production lines, the mechanics for the final finished sheet billet that the present invention obtains
Performance is：Yield strength >=550MPa, tensile strength >=680MPa, elongation ＞ 10.0%, yield tensile ratio ＜ 0.94,180 ° of clod wash
Performance is qualified.Weatherability is equivalent to corten-A.
The corten-A is to examine the one kind for stepping on steel, is the representative steel grade of U.S.'s Cu-P Series Steels, belongs to low-alloy high-strength
Structural steel resisting atmosphere corrosion, the country are called weathering steel.
The ESP production lines are the sheet billet endless rollings of new generation of Italian Giovanni Arvedi companies invention
Production line, it has the major techniques such as higher casting rate, stable casting phase technology controlling and process, extensive automatic technology special
Point.
The reverse temperature field refers to that strand has the characteristics of surface and core temperature are higher, and temperature is relatively low at 1/4 thickness.
A kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel of the present invention has following advantageous effects：
(1) preparation method of the invention by build up and precipitation strength, can improve the power of final finished sheet billet
Learn performance.
(2) application of the preparation method of a kind of 550MPa levels Ultra-fine Grained high-strength weathering steel of the invention on ESP production lines,
The big Reduction Technology of roughing and middle base induction heating technique are employed in a creative way, produce grain size number up to 13.0~13.5
Ultra-fine Grained high-strength weathering steel.
(3) weathering steel that preparation method of the invention obtains has that surface and core crystal grain are thicker, and crystal grain is thinner at 1/4 thickness
Tissue signature so that sheet billet has good cold forming capability, good atmospheric corrosion resistance, improves weathering steel
Service life.
(4) preparation method of compact, efficient endless rolling of the invention, can either meet Thin Specs high-strength weathering automobile
The production technology demand of Strip, realization " with Bao Daihou " effect, make Vehicle mass reduction, so that effective load of automobile
Quality increase, fuel consumption reduce and conevying efficiency improves；And can is enough on the premise of production procedure is shortened, and improves weathering steel
Surface quality, reduce the thickness specification of weathering steel, realize and " with hot Dai Leng " technique effect, improve the production effect of weathering steel
Rate, weathering steel production cost is reduced, while reduces energy consumption, reduce discharge, reach resources conservation, environmentally friendly production
Effect.
(5) continuous casting billet that method of the invention obtains by continuous casting step directly carries out roughing to it, without traditional work
Technological process is shortened to the reheating link of strand before roughing in skill, higher unit production is obtained while reducing energy consumption
Amount.
(6) drafts big under method roughing step high temperature of the invention causes original austenite grain significantly to refine,
Organization foundation is provided for final uniform tiny ferritic structure.
(7) in method of the invention, middle base processing step accurately controls middle base essence and pricks inlet temperature, meets to prick eventually
Temperature requirement；Meanwhile middle base surface temperature is high after sensing heating, core temperature is low, and this reverse temperature field is slab thickness
The special tissue signature in direction (surface and core are thicker, thinner at 1/4 thickness) provides temperature basis.
(8) single pass rolling reduction of finish rolling step is 30%-40% in method of the invention, can enter austenite crystal
Step refining, in addition, finishing temperature is relatively low to ensure that austenite rolls in Unhydrated cement, increase dislocation density, increase deformation
Energy storage, improve the forming core speed of deformation induced ferrite and deformation-induced precipitation in follow-up cooling procedure.
(9) laminar flow cooling step use the intensive type of cooling of leading portion in method of the invention, and cooling velocity for 50% with
On；This leading portion is intensive and the faster type of cooling, can make build up, and then improve the mechanical property of final products.
(10) preparation method of the invention is applied on ESP production lines, have low cost, low energy consumption, it is compact, efficiently give birth to
The characteristics of output dimensional accuracy high-performance excellent hot rolled thin strip coil of strip.
Brief description of the drawings
Fig. 1 is the schematic diagram of application of the preparation method of the present invention on ESP production lines.
Fig. 2 is the SEM patterns of the ferrite crystal grain at the thickness of weather-resistant steel plate 1/4 in the embodiment of the present invention 1.
Fig. 3 is the precipitate SEM patterns that nanoscale even dispersion is distributed in the embodiment of the present invention 1.
Fig. 4 is the section SEM patterns of the corrosion products film that slab is formed in atmospheric environment in the embodiment of the present invention 1.
Description of reference numerals：The straight circular-arc type continuous casting machine of 1- tundish, 2-, 3- roughing mills, 4- rocking shears, 5- push away useless roller-way, 6-
Rotating hub is cut, 7- induction heaters, 8- high pressure dephosphorization case, 9- finishing mills, 10- laminar cooling systems, 11- high-speed flying shears, 12- undergrounds
Coiling machine.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is explained in further detail.It should be appreciated that specific embodiment described herein is used only for explaining the present invention, and
It is not used in the restriction present invention.
On the contrary, the present invention covers any replacement done in the spirit and scope of the present invention being defined by the claims, repaiied
Change, equivalent method and scheme.Further, in order that the public has a better understanding to the present invention, below to the thin of the present invention
It is detailed to describe some specific detail sections in section description.Part without these details for a person skilled in the art
Description can also understand the present invention completely.
Embodiment 1
The present embodiment provides a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel, as Figure 1-Figure 4.Its work
Skill flow is as follows：
Middle Baogang's water is prepared first：Initial feed is melted to pass through BOF converter refinings, LF stoves essence successively after obtaining molten iron
Refining, the refining of RH refining furnaces, obtain middle Baogang's water.
Then middle Baogang's water is put into ESP production lines as shown in Figure 1.
Pass through continuous casting step → roughing step → middle base processing step → finish rolling step → section cooling in ESP production lines
Step → batch step obtains finished sheet base.
Middle Baogang's water forms the continuous casting billet that thickness is 80mm by straight circular-arc type continuous casting machine 2.
The continuous casting billet is directly entered 3 frame roughing mills 3 under 3-7m/min high pulling rate and carries out roughing；
The drafts of the big pressure of the single pass of single roughing mill is 50%-60% in the roughing step.The roughing enters
Mouth temperature is 1163 DEG C.
The middle base processing step includes：The middle base successively by rocking shears 4, push away useless roller-way 5, after rotating hub cuts 6,
Temperature T is quickly heated up into induction heater 71, the middle base after being handled；
The temperature T1Entry temperature at finishing as the middle base.
The temperature T1For 1160 DEG C.
The finish rolling step includes：Middle base temperature after the treatment uses 5 frame mm finishing mill units 9 when being 1160 DEG C
5 passage pressures are carried out, obtain finished sheet base.
The thickness specification of the sheet billet is 1.4mm, width specifications 1500mm.
The finishing temperature of the finish rolling step is 825 DEG C.
The drafts of the single pass pressure of the single finishing mill of the finish rolling step is 30%-40%.
The section cooling step includes：The finished sheet base that the finish rolling step is obtained, by equipped with elevated tank
Laminar cooling system, take the intensive type of cooling of leading portion, the finished sheet base cooled down, is cooled to coiling temperature
T2, the finished sheet base that is cooled down.
The temperature T2For 620 DEG C.
In the section cooling step, cooling velocity is more than 50%.
The step of batching includes：Batch, roll up after the finished sheet base that the section cooling step obtains is carried out into bundling
Take temperature T2, it is slowly cooled to room temperature after batching.
The bundling process carries out bundling using high-speed flying shear 11.
The coiling process is batched using downcoiler 12.
The preparation method also includes dephosphorization step, and the dephosphorization step is placed in the middle base processing step and the essence
Roll between step.
The dephosphorization step includes：Middle base after the processing obtained using high pressure dephosphorization case 8 to middle base processing step
Carry out dephosphorization.
The chemical composition of the initial feed technological parameter related in preparation method is as shown in following table 1-1.
The chemical compositions of the table 1-1 initial feeds technological parameter related in preparation method
According in the chemical composition and preparation method of preparation method of the present invention and the present embodiment selection initial feed
Application of the related technological parameter on ESP production lines, the 550MPa level Ultra-fine Graineds high-strength weathering steel being prepared is (hereinafter referred to as
Weathering steel) product specification, mean grain size and mechanical property as shown in following table 1-2.
Product specification, mean grain size and the mechanical property of table 1-2 550MPa level Ultra-fine Grained high-strength weathering steels
The weathering steel obtained to the present embodiment by the preparation method of the present invention is analyzed as follows：
Fig. 2 is the SEM patterns of the ferrite crystal grain at the thickness of weather-resistant steel plate 1/4, straight through measurement, the average crystal grain of weathering steel
Footpath is 3.73 μm, and grain size number is 13.0 grades.As seen from the figure, section cooling step is intensive using leading portion and faster cooling side
Formula, the mechanical property of final products can be improved by build up.
Fig. 3 is the precipitate SEM patterns of nanoscale even dispersion distribution.As seen from the figure, Ti, Nb, V, Mo nano-scale carbon
Nitride is fully separated out, and the mechanical property of weathering steel can be further improved by strong precipitation strength effect.
Fig. 4 is the section SEM patterns for the corrosion products film that weathering steel is formed in atmospheric environment.As seen from the figure, weathering steel
In atmospheric environment, the surface of weathering steel forms double-deck corrosion products film；The internal layer of weathering steel is mainly Cr, Ni oxide,
Fine and close corrosion products film is formed, passivation is generated to matrix, improves the corrosion resisting property of matrix；The outer layer master of weathering steel
To be Fe oxide and CuS, wherein CuS integrated distributions plug outer layer corrosion products film in the hole of dimple shape rusty scale,
The infiltration of air inner layer is prevented, so as to reduce the corrosion rate of matrix.Therefore, this bilayer that weathering steel has is anti-corrosion
Mechanism so that average corrosion rate of the weathering steel in atmospheric environment is less than 0.08g/ (m2·h)。
Embodiment 2
The present embodiment use method it is substantially the same manner as Example 1, unlike the initial feed chemical composition and
The product specification of related technological parameter and the 550MPa level Ultra-fine Grained high-strength weathering steels being prepared, average crystalline substance in preparation method
Granularity and mechanical property.
The chemical composition of the initial feed technological parameter related in preparation method is as shown in following table 2-1.It is described
Product specification, mean grain size and the mechanical property of 550MPa level Ultra-fine Grained high-strength weathering steels are as shown in following table 2-2.
The chemical compositions of the table 2-1 initial feeds technological parameter related in preparation method
It is related in preparation method according to the chemical composition of preparation method of the present invention and the present embodiment initial feed
Technological parameter, product specification, mean grain size and the mechanical property of the 550MPa level Ultra-fine Grained high-strength weathering steels being prepared
Can be as shown in following table 1-2.
Product specification, mean grain size and the mechanical property of table 2-2 550MPa level Ultra-fine Grained high-strength weathering steels
Claims (10)
1. a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel, it is characterised in that the preparation method includes continuous casting
Step, roughing step, finish rolling step, section cooling step and batch step；
The preparation method be by initial feed successively by continuous casting step, roughing step, finish rolling step, section cooling step and
After batching step, final finished sheet billet is obtained；
The roughing step includes：The continuous casting billet that the continuous casting step obtains is directly over M frame roughing mills under high pulling rate
Group carries out the big pressure of M passages, obtains middle base；The M is positive integer；
The roughing step and finish rolling step are full endless rolling.
A kind of 2. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 1, it is characterised in that institute
Stating preparation method also includes middle base processing step；
The middle base processing step is after the roughing step；
The middle base processing step includes：The middle base that the roughing step is obtained is placed in induction heater and quickly heated up to
Temperature T1, the middle base after being handled；
The temperature T1For 1100-1200 DEG C.
A kind of 3. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 2, it is characterised in that institute
Stating finish rolling step includes：N passage pressures are carried out to the middle base after the processing using N frames mm finishing mill unit, obtain sheet billet；
The N is positive integer；
The section cooling step includes：The sheet billet is passed through into the laminar cooling system equipped with elevated tank, takes leading portion
The intensive type of cooling, the sheet billet is cooled to coiling temperature T2, obtain cooling down sheet billet；
The step of batching includes：By coiling process after the cooling sheet billet progress bundling, coiling temperature T when batching2, batch
After be air-cooled to room temperature, obtain final finished sheet billet；
The coiling temperature T2For 620-660 DEG C.
A kind of 4. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 1, it is characterised in that institute
M is stated not less than 3.
A kind of 5. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 1, it is characterised in that institute
It is 3-7m/min to state high pulling rate.
A kind of 6. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 3, it is characterised in that institute
N is stated not less than 5.
A kind of 7. preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 1, it is characterised in that institute
Stating preparation method also includes dephosphorization step, and the dephosphorization step is placed in before the finish rolling step.
8. a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim any one of 1-7, it is special
Sign is that the chemical composition of the initial feed includes：Carbon, silicon, aluminium, manganese, copper, titanium, niobium, nickel, chromium, phosphorus, sulphur, nitrogen and iron；
The mass fraction of each chemical composition of initial feed is：0.02-0.06% carbon, 0.1-0.4% silicon, 1.0-1.7% manganese,
0.01-0.05% aluminium, 0.1-0.4% copper, titanium 0.04-0.08%, niobium 0.02-0.05%, nickel 0.1-0.3%, chromium 0.3-
0.7%th, phosphorus≤0.015%, sulphur≤0.003%, nitrogen≤0.004%, surplus are iron.
9. a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim any one of 1-7 is in ESP
Application on production line.
10. a kind of preparation method of 550MPa levels Ultra-fine Grained high-strength weathering steel according to claim 9 is on ESP production lines
Application, it is characterised in that the ESP production lines total length is 180-210m.
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Cited By (7)
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| CN108486466A (en) * | 2018-04-23 | 2018-09-04 | 马钢(集团)控股有限公司 | A kind of yield strength 550MPa grade high ductility weather-resistant steel plates and preparation method thereof |
| CN109266960A (en) * | 2018-09-26 | 2019-01-25 | 武汉钢铁有限公司 | Using the tensile strength >=800MPa thin gauge weathering steel and method of short route production |
| CN109338212A (en) * | 2018-09-26 | 2019-02-15 | 武汉钢铁有限公司 | Using the yield strength >=550MPa thin gauge weathering steel and method of short route production |
| CN109881091A (en) * | 2019-02-21 | 2019-06-14 | 江苏沙钢集团有限公司 | A kind of high-strength weathering steel strip and its production method |
| CN111101071A (en) * | 2020-02-25 | 2020-05-05 | 湖南华菱涟源钢铁有限公司 | High-strength weathering steel and production method thereof |
| CN111702010A (en) * | 2020-06-23 | 2020-09-25 | 中冶赛迪工程技术股份有限公司 | Production process of thin strip by continuous casting and rolling |
| CN112176259A (en) * | 2020-10-14 | 2021-01-05 | 邯郸钢铁集团有限责任公司 | 550 Mpa-grade high-strength weathering steel and production method thereof |
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| CN106367686A (en) * | 2016-08-30 | 2017-02-01 | 日照宝华新材料有限公司 | Method of producing weathering steel by thin slab casting and rolling process based on ESP |
| CN106702283A (en) * | 2016-12-30 | 2017-05-24 | 日照宝华新材料有限公司 | Method for producing thin-gauge S355J0W steel based on ESP sheet billet continuous casting and rolling process |
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| CN106367686A (en) * | 2016-08-30 | 2017-02-01 | 日照宝华新材料有限公司 | Method of producing weathering steel by thin slab casting and rolling process based on ESP |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108486466A (en) * | 2018-04-23 | 2018-09-04 | 马钢(集团)控股有限公司 | A kind of yield strength 550MPa grade high ductility weather-resistant steel plates and preparation method thereof |
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| CN109338212A (en) * | 2018-09-26 | 2019-02-15 | 武汉钢铁有限公司 | Using the yield strength >=550MPa thin gauge weathering steel and method of short route production |
| CN109881091A (en) * | 2019-02-21 | 2019-06-14 | 江苏沙钢集团有限公司 | A kind of high-strength weathering steel strip and its production method |
| CN109881091B (en) * | 2019-02-21 | 2021-06-15 | 江苏沙钢集团有限公司 | High-strength weather-resistant steel thin strip and production method thereof |
| CN111101071A (en) * | 2020-02-25 | 2020-05-05 | 湖南华菱涟源钢铁有限公司 | High-strength weathering steel and production method thereof |
| CN111702010A (en) * | 2020-06-23 | 2020-09-25 | 中冶赛迪工程技术股份有限公司 | Production process of thin strip by continuous casting and rolling |
| CN111702010B (en) * | 2020-06-23 | 2022-03-11 | 中冶赛迪工程技术股份有限公司 | Production process of thin strip by continuous casting and rolling |
| CN112176259A (en) * | 2020-10-14 | 2021-01-05 | 邯郸钢铁集团有限责任公司 | 550 Mpa-grade high-strength weathering steel and production method thereof |
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