CN106498307A - The good high-strength and high ductility lightweight steel of 780MPa level cold-forming properties and its manufacture method - Google Patents
The good high-strength and high ductility lightweight steel of 780MPa level cold-forming properties and its manufacture method Download PDFInfo
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- 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
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Abstract
The invention discloses good high-strength and high ductility lightweight steel of a kind of 780MPa levels cold-forming property and preparation method thereof, the ladle includes following component and its percentage by weight：C：0.15～0.60%, Si：0.01～0.70%, Mn：1.00～6.00%, Al：3.0～6.0%, Cr：0.10～2.0%；P≤0.015%, S≤0.010%, N≤0.008%, remaining are Fe and inevitable impurity, and the weight of Cr, Al and Si meets following relation：0.05≤Cr/(Al+Si)≤0.40.The product of the present invention possesses the tensile strength of more than 780MPa, more than 30% elongation percentage, the existing advanced high-strength steel of density ratio reduces by more than 5%, can improve the stability and the uniformity of thickness direction structure property of austenite in steel tissue effectively by surface-carburized layer control below 10 microns.
Description
Technical field
The present invention relates to automobile steel production technology, in particular to a kind of good high-strength height of 780MPa levels cold-forming property
Tough lightweight steel and its manufacture method.
Background technology
In order to reduce fuel consumption, it is one of effective ways to improve fuel efficiency by mitigation vehicle weight.Mitigate vapour
The weight of car parts mainly has two methods, and a kind of realized using the method for intensity and then thickness thinning is improved, another
It is then on the basis of equality strength is ensured to plant, and realizes the loss of weight of part by the density of reduction steel.By reducing steel
Material density is realized in the prior art of loss of weight, as Al has low-density feature, therefore main by steel in prior art
The middle Al for adding different content（3.0～10.0wt%）To realize that the automobile of each intensity rank (tensile strength highest 1000MPa) is used
Steel is developed, and density can be reduced to 6800Kg/m3, such as：Chinese patent application CN104928569A discloses a kind of 800MPa Gao Yan
The low density steel of malleability and its manufacture method, disclose a kind of ferrite low-density high in Chinese patent application CN104928568A
Strong steel and its manufacture method.But these prior arts are suffered from the drawback that：Due to adding substantial amounts of Al, steel surface decarburization in steel
Seriously, unstable austenite or martensite is formed, in steel, separates out thick carbide, reduce the steel forming property of material,
In hot rolling and cold-rolling process the problems such as easily cracking and broken belt, lumber recovery and production efficiency is caused to be greatly reduced.
Content of the invention
Present invention aim to provide a kind of good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property and its
Manufacture method, the lightweight steel density are low, and intensity is high and formability is good.
For achieving the above object, the technical solution used in the present invention is：A kind of good height of 780MPa levels cold-forming property
Strong high-ductility lightweight steel, it is characterised in that：The ladle includes following chemical composition and its percentage by weight：C：0.15～0.60%, Si：
0.01～0.70%, Mn：1.00～6.00%, Al：3.0～6.0%, Cr：0.10～2.0%；P≤0.015%, S≤0.010%, N≤
0.008%, remaining is Fe and inevitable impurity, and the weight of Cr, Al and Si meets following relation：0.05≤Cr/(Al+
Si)≤0.40.
Further, the chemical composition of the steel also includes one or more element in V, Ti, Mo, Nb and Zr.
Further, the steel also includes following chemical composition and its percentage by weight：V：0.01～0.20%, Ti：0.03
～0.30%, Mo：0.10～0.50%, Nb：0.02～0.20%, Zr：0.001～0.10%, and Cr, V, Ti, Mo, Nb, Zr, Al and
The weight of Si meets following relation：0.05≤(Cr+V+Ti+Mo+Nb+Zr)/(Al+Si)≤0.40.
Further, the steel also includes following chemical composition and its percentage by weight：Ni：0.01～1.00%, Cu：
0.01～2.0%, Ca：0.0001～0.10%.
Further, the weight of Cr, Al and Si meets following relation：0.05≤Cr/(Al+Si)≤0.25.
Further, Cr, the weight of V, Ti, Mo, Nb, Zr, Al and Si meet following relation：0.05≤(Cr+V+Ti+Mo+
Nb+Zr)/(Al+Si)≤0.25.
A kind of manufacture method of the good high-strength and high ductility lightweight steel of above-mentioned 780MPa levels cold-forming property, including smelting, even
Casting, heating, hot rolling, cooling are batched, and pickling is cold rolling, are annealed and coating step, it is characterised in that：In the continuous casting step, pour
Al in the covering slag that casting is adopted2O3And SiO2Mass ratio Al2O3/SiO2≥1.0；In the heating stepses, slab heating rate
For 5～50 DEG C/min, slab tapping temperature is 1050～1200 DEG C, and the heat time is 10～200min；In the hot-rolled step,
850～950 DEG C of hot rolling finishing temperature；In the cold rolling step, cold rolling reduction is 40～85%；In the annealing steps, adopt
Continuous annealing, continuous annealing soaking temperature are Tmin～900 DEG C, Tmin=（721-36*C-20*Mn+20*Al+23*Si+50*Cr）
DEG C, soaking time is 20～300s, and after soaking, rapid cooling section begins to cool down temperature >=680 DEG C, cooldown rate >=5 DEG C/s.
Further, in the continuous casting step, using sheet blank continuous casting or slab CC machine, during using sheet blank continuous casting,
Slab charging temperature >=700 DEG C, during using slab CC machine, carry out slow cooling, cooling speed using stay-warm case in slab cooling procedure
Rate≤50 DEG C/min, and slab charging temperature >=200 DEG C.
Further, in the cooling step, quickly cooled down using leading portion, cooldown rate >=5 DEG C/s；Described batch step
In, coiling temperature is 550～650 DEG C.
Further, in the annealing steps, dew point of atmosphere temperature≤- 20 DEG C, H are controlled2Volumetric concentration >=5%.
Further, in the annealing steps, dew point of atmosphere temperature≤- 40 DEG C, H are controlled2Volumetric concentration >=8%.
Further, in the coating step, during hot-dip, stabilization temperature is 400～500 DEG C, and the stabilisation time is
10～300s, during tempering, temperature is 150～400 DEG C, and tempering time is 10～300s.
Further, in the hot-rolled step, after hot rolling, the tissue of steel includes ferrite and K carbide, its volume hundred
Divide ratio >=95%, K carbide lamellar spacing≤0.5 micron also includes retained austenite or the martensite of percent by volume≤5%；
In the cold rolling step, the tissue of cold rolling rear steel includes ferrite, austenite or ferrite, bainite and austenite structure, and
Austenite volume fraction >=15%.
In annealing and coating step, when carrying out hot-dip, 400～500 DEG C of stabilization temperature, stabilize time 10～
300s；When being tempered, 150～400 DEG C of temperature, time are 10～300s.
Reason is selected to be analyzed as follows each element content in the present invention：
C：Carbon can play solution strengthening effect in steel, or with steel in Ti, the carbide former shape such as Nb, V, Zr, Mo
Into MC fine particles, play a part of precipitation strength and crystal grain thinning, improve the intensity of steel.Carbon may also function as stable austenite
Effect, improve the C in steel, can improve the content and stability of retained austenite in steel, increase the plasticity of steel.But carbon contains
The too high welding performance that decarburization in steel can be caused serious, and can affect steel of amount, therefore in steel of the present invention, the percentage by weight of C contains
Amount is chosen as 0.15～0.60%, preferably 0.15～0.45%.
Mn：Mn plays solution strengthening and stable austenite in steel, and content is too low, and invigoration effect is too little, it is impossible to shape
Into a certain amount of austenite, the toughness needed for steel is not reached.Mn too high levels easily form serious inclined in strip mid-depth
Analysis, reduces toughness of products, is easily caused cracking in forming process, therefore the weight percent content of Mn of the present invention for 1.0～
6.0%.
Si：Si plays solution strengthening effect in steel, and Si contents are too low, and solid solution strengthening effect is not obvious, but Si also improves steel
The activity of middle C, promotes the skin decarburization of steel, and in addition Si too high levels also have a negative impact to surface quality of steel, therefore
The weight percent content of Si of the present invention is 0.01～0.70%, preferably 0.01～0.30%.
Al：Al is lightweight element, as its atomic mass is little and bigger than iron atom radius, can effectively reduce the close of steel
Degree, is therefore main adding elements in lightweight steel, and Al may also function as solution strengthening effect, but Al constituent contents are too high can be formed
Compound between FeAl, reduces steel toughness, and substantial amounts of Al promotes steel surface decarburization, causes steel surface tissue and central. set
Knit inequality, it is impossible to obtain the microstructure for requiring, therefore the weight percent content of Al is 3.0～6.0% in the present invention, preferably
3.5～5.5%.
Cr：Cr is solution strengthening element, can improve the intensity of steel, in addition, Cr can improve the activation energy of C atoms in steel,
Reduce the activity of C, the excessive carbide of the too high easy formation of the effectively decarburization of mitigation steel, but Cr contents simultaneously causes C diffusions slow
Slowly, phase transformation is adversely affected, therefore in the present invention, the weight percent content of Cr is 0.10～2.0%.
In the present invention Cr, Al, Si, V, Ti, Nb, Mo, Zr constituent content need to meet 0.05≤Cr/ (Al+Si)≤0.40 or
0.05≤(Cr+V+Ti+Mo+Nb+Zr)/(Al+Si)≤0.40.As Cr/ (Al+Si) >=0.05 or (Cr+V+Ti+Mo+Nb+
Zr)/(Al+Si) >=0.05 when, skin decarburization caused by high level Al, Si in steel can be avoided, even tissue is made, steel plate is improved
The compatibility of deformation ability at surface and center, and the stability of retained austenite will also be improved, so as to avoid the defects such as face crack
Generation, if but when Cr/ (Al+Si) >=0.40 or (Cr+V+Ti+Mo+Nb+Zr)/(Al+Si) >=0.40, exist in steel and separate out
The risk of excessive thick carbide, so as to reduce the forming property of steel, and Cr etc. constituent content is higher is unfavorable for continuous annealing isothermal
Process C is redistributed.It is preferred that 0.05≤Cr/ (Al+Si)≤0.25 or 0.05≤(Cr+V+Ti+Mo+Nb+Zr)/(Al+Si)
≤0.25.
P：P is the impurity element in steel, it is easy in Grain Boundary Segregation, affect the toughness of product, therefore its content is more low better.
According to actual control level, its weight percent content should be controlled below 0.015%.
S：S be steel in impurity element, easily crystal boundary produce segregation, and with steel in Fe formed low melting point FeS, reduce
The toughness of steel, fully should remove during steel-making, and its weight percent content should be controlled below 0.010%.
N：N is the impurity element in steel, reduces the toughness of steel, and in easy and steel, Al, Ti form AlN and TiN, content mistake
Height, easily forms thick AlN and TiN, therefore reduces its content as far as possible, should control below 0.008%.
Ti：Ti plays solution strengthening effect in steel, and Ti combines to form TiC and TiN with C, the N in steel, plays precipitation strong
The effect of change, Ti also reduce the activity of C in steel, so as to reduce the tendency of steel decarburization.But Ti too high levels bring cost to increase,
Therefore in the present invention, the weight percent content of Ti is 0.03～0.30%.
Nb：Nb plays C, the N in solution strengthening effect, with steel in steel and combines to form TiC and TiN, plays precipitation strength
Effect, but Nb too high levels can increase the manufacturing cost of steel, and therefore in the present invention, the weight percent content of Nb is 0.02
～0.20%.
V：V plays C, the N in solution strengthening effect, with steel in steel and combines to form VC and VN, plays the work of precipitation strength
With, but the too high manufacturing cost that can increase steel of V content, therefore in the present invention weight percent content of V be 0.01～
0.20%.
Mo：The C that Mo is played in solution strengthening effect, with steel in steel combines to form MoC, plays a part of precipitation strength,
But Mo too high levels can increase the manufacturing cost of steel, therefore in the present invention, the weight percent content of Mo is 0.10～0.50%.
Zr：The C that Zr is played in solution strengthening effect, with steel in steel combines to form ZrC, plays a part of precipitation strength,
But Zr too high levels can increase the manufacturing cost of steel, therefore the present invention in Zr weight percent content be 0.001～
0.10%.
Ni：Ni is among the austenite stabilizing elements, and improves the low-temperature flexibility of steel, but Ni is expensive, therefore in the present invention
The weight percent content of Ni is 0.01～1.00%.
Cu：Cu is among the austenite stabilizing elements, and plays a part of solution strengthening and precipitation strength in steel, but Cu is too high right
Surface quality has a negative impact, and due to expensive, therefore in the present invention weight percent content of Cu be 0.01～
2.0%.
Ca：The calcium of certain content can improve the state of steel inclusion, so as to be conducive to the toughness for improving steel, therefore this
The weight percent content of bright middle Ca is 0.0001～0.10%.
Main technique reason in the present invention is analyzed as follows：
As in steel, Al content is high, Al easily with SiO in covering slag2React, table occur so as to cause continuous casting high-aluminum steel
Face quality problems, therefore, present invention control Al2O3/SiO2≥1.0.
Due to adding substantial amounts of Al to improve the thermal coefficient of expansion of steel in steel, add speed too high, easily cause continuous casting
Base produces cracking because internal stress is excessive, and addition speed is too low, and the heat time is long, causes skin decarburization serious, crystal grain in steel
Thick, reduce the toughness of steel.Therefore, the rate of heat addition of the present invention is 5～50 DEG C/min.
Element of the slab tapping temperature at 1050～1200 DEG C, when being because that heating-up temperature is low, in steel is controlled in the present invention
It is difficult to spread, uniformity is poor in steel, and the too low slab plasticity of temperature reduces, resistance of deformation increases, and easily produces side and splits problem,
And temperature is too high easily causes that decarburization is serious and coarse grains.
The heat time of the present invention is 10～200min, and the heat time is too short, the poor temperature uniformity of slab, alloying element
Diffusion is insufficient, and the heat time is oversize, easily causes steel slab surface decarburization serious.Therefore the present invention controls the heat time for 10
～200min.
The finishing temperature of the present invention is 850～950 DEG C, and finishing temperature is too high, and band crystalline grain of steel fully can not be refined, and
Decarburization can be increased, finishing temperature is too low, resistance of deformation increases, and easily separates out thick carbide (FeMn)3AlC（K carbide）,
Board rolling is caused to ftracture.
After hot rolling of the present invention, strip cooldown rate >=5 DEG C/s, 550 DEG C～650 DEG C of coiling temperature.Strip cooldown rate mistake
Low, thick K carbide is separated out in steel, is reduced the plasticity during cold rolling of strip steel, is caused rolling crack.Coiling temperature is too high,
In steel, thick K carbide is easily separated out, reduce the deformability of steel, ftractureed in follow-up cold-rolled process, coiling temperature
Too low, easily in steel, martensite is formed, also result in deformability reduction, roll easy to crack.
In the present invention, cold rolling reduction is 40～85%, the cold roller and deformed tiny K carbonizations for crushing formation in coiling process
Thing, improves the dislocation in strip, is to provide substantial amounts of forming core point, fining ferrite and austenite crystal in annealing, but deforms
Amount is excessive, causes plasticity to reduce, and resistance of deformation increases, and easily causes steel edge portion cracking and broken belt.
In the present invention, continuous annealing soaking temperature is Tmin～900 DEG C, 20～300s of soaking time, and Tmin=721-36*C-
The factors such as the C in 20*Mn+20*Al+23*Si+50*Cr, the carbide dissolution temperature in steel and steel, Mn, Al, Si, Cr are related,
Soaking temperature is too low, easily separates out K carbide and promote K carbide to grow up in steel, and soaking time is too short, and K carbide can not be weighed
Austenite is entered in new solid solution, it is impossible to forms a certain amount of stable austenite and reaches required tissue.Soaking temperature is too high and equal
Hot overlong time, causes austenite crystal thick and carbide is thick, so as to increase the content of martensite in final products tissue,
Same reduction forming property.
In the present invention, rapid cooling started temperature >=680 DEG C after soaking, rapid cooling started temperature are too low, have the wind to form K carbide
Danger.Rapid cooling section cooldown rate >=5 DEG C/s, can effectively reduce K Carbide Precipitations risk in steel, improve the stability of austenite, from
And improve the crystallized ability of steel.
In the present invention, it is tempered or stabilization of austenite at 150～500 DEG C after rapid cooling, is tempered or stabilization of austenite
10～300s of time, when temperature is less than 150 DEG C and when the time is shorter than 10s, it is impossible to eliminate residual stress, do not reach bating effect,
When temperature is longer than 300s higher than 500 DEG C with the time, there is the risk of martensite decomposition and carbide precipitate, and then reduce material
Deformability.For coating process, 400～500 DEG C are conducive to the formation of coated layer and stablize.
In the present invention, in continuous annealing furnace, dew point of atmosphere controls, below -20 DEG C, to be preferably controlled in less than -40 DEG C, H2Dense
Degree >=5%, preferably H2Concentration >=8%, advantageously reduces surface oxidation and decarburization.
Compared with prior art, there is advantages below in the present invention：
First, the present invention provides a kind of good 780MPa grade high strength and high toughness lightweight steel of processing characteristics and its manufacture method,
The product of the present invention possesses the tensile strength of more than 780MPa, and more than 30% elongation percentage, properties of product have met or exceeded often
The performance of advanced high-strength steel is advised, the existing advanced high-strength steel of density ratio reduces by more than 5%, possesses good loss of weight potentiality, especially suitable
Manufacture in automobile structure and reinforcement.
Second, the product of the present invention is overcome in prior art due to C, Al content is high and the skin decarburization problem brought,
The stability and thickness direction group of austenite in steel tissue can be improve effectively by surface-carburized layer control below 10 microns
The uniformity of performance, and then the deformability of raising product is knitted, side in production process is substantially reduced and is split occurrence risk, improve life
Lumber recovery and production efficiency during product.
Third, the tissue of the hot-rolled product of the present invention predominantly ferrite+tiny K carbide, K carbide lamellar spacings≤
0.5 micron, percent by volume≤5% of retained austenite or martensite；Cold-rolled products of the present invention are organized as ferrite+Ovshinsky
Body or ferrite+bainite+austenite structure, and austenite volume fraction >=15%.
Fourth, the manufacture method of steel of the present invention is based on existing production system and equipment condition, solve the hot rolling of lightweight steel and
The problem easily cracked in cold-rolled process, further increases production efficiency and lumber recovery.
Specific embodiment
With reference to specific embodiment, the present invention is described in further detail, is easy to more clearly understand the present invention,
But they do not constitute to the present invention and limit.
Embodiment 1～11
Various embodiments of the present invention follow the steps below production（Smelting, continuous casting → heating or soaking → rolling → laminar flow
Cool down → batch → pickling → cold rolling → continuous annealing → finished product）：
1）Smelting, continuous casting：Slab can adopt thin-belt casting rolling, the mode such as sheet blank continuous casting or conventional slab CC machine to produce,
And Al in adopted covering slag of casting2O3And SiO2Mass percent Al2O3/SiO2≥1.0.
2）Above-mentioned continuous casting steel billet is heated：5～50 DEG C/min of heating of plate blank speed, slab tapping temperature 1050～
1200 DEG C, 10～200min of heat time.When using sheet blank continuous casting, slab charging temperature answers >=700 DEG C；When adopting slab
During base continuous casting, in slab cooling procedure, slow cooling, cooldown rate≤50 DEG C/min, and slab charging temperature should be carried out using stay-warm case
≥200℃.
3）Hot rolling：850～950 DEG C of hot rolling finishing temperature.
4）Steel band after by hot rolling is cooled down and is batched：Strip cooling is quickly cooled down using leading portion, cooldown rate >=5
DEG C/s, 550 DEG C～650 DEG C of coiling temperature.Include leading portion cooling and two sections of coolings, preferably leading portion cooling in the type of cooling.
5）Pickling.
6）Cold rolling：Cold rolling reduction 40-85%.
7）Annealing and coating：Using continuous annealing, continuous annealing soaking temperature is Tmin～900 DEG C, Tmin=（721-36*C-
20*Mn+20*Al+23*Si+50*Cr）DEG C, the element in foregoing relationships refers to the percentage composition of the element in steel, soaking time
20～300s, after soaking, rapid cooling section begins to cool down temperature >=680 DEG C, and cooldown rate >=5 DEG C/s are entered at 150～500 DEG C after rapid cooling
Row tempering is stabilized, and tempering stabilizes 10～300s of time, and then slow cooling is to room temperature.In continuous annealing, dew point of atmosphere control
System is preferably controlled in less than -40 DEG C, H below -20 DEG C2Volumetric concentration >=5%, preferably H2Volumetric concentration >=8%；Carry out hot-dip
When, 400～500 DEG C of stabilization temperature stabilizes 10～300s of time, when being tempered, 150～400 DEG C of temperature, and the time
10～300s.
The specific chemical composition of embodiment 1～11 and comparative example 1～3 see the table below 1（wt%）；Embodiment 1～11 and comparative example
1～3 hot rolling and the major parameter such as cold rolling control and effect see the table below 2；Embodiment 1～11 and comparative example 1～3 cold rolling and move back
Ignition technique state modulator see the table below 3；The implementation result of embodiment 1～11 and comparative example 1～3 see the table below 4.
Table 1
Table 2
From Table 2, it can be seen that steel surface quality is good obtained in embodiment 1～11, not cracking phenomenon.And comparative example
1 and comparative example 3 due to being unsatisfactory for the condition of 0.05≤Cr/ (Al+Si)≤0.40 in steel, thus occur in that in the operation of rolling tight
The thick carbide of the skin decarburization of weight and precipitation, cracking in cold-rolled process so as to cause；Due to adding in the steel of comparative example 2
Having added excessive Cr, having caused thick carbide and martensitic structure to be occurred in that in hot-rolled product tissue, therefore deformability is poor,
Cause to ftracture.
Table 3
Above-described embodiment and comparative example adopt continuous annealing, continuous annealing soaking temperature Tmin～900 DEG C, soaking time 20
～300s, after soaking, rapid cooling section begins to cool down temperature >=680 DEG C, and cooldown rate >=5 DEG C/s are carried out at 150～500 DEG C after rapid cooling
Tempering is stabilized, and tempering stabilizes 10～300s of time, and then slow cooling is to room temperature, to embodiment and the mechanical property of comparative example
Can test, as a result see the table below 4.
Table 4
From table 4, it can be seen that the product tensile strength of the embodiment of the present invention 1～11 is up to more than 816MPa, in embodiment 5
Even up to 901MPa；Elongation percentage reaches 41% up to more than 30% in embodiment 9, properties of product have met or exceeded existing elder generation
Enter the performance of high-strength steel, and the existing advanced high-strength steel of its density ratio reduces by more than 5%；In addition, the final surface-carburized layer thickness of product
Within 2 microns, surface quality is extremely excellent for control.And comparative example 1 and 3 product surface decarburized layer of comparative example are blocked up, comparative example 1
, below 25%, mouldability is poor for～3 elongation percentage.
Claims (10)
1. the good high-strength and high ductility lightweight steel of a kind of 780MPa levels cold-forming property, it is characterised in that：The ladle includes following chemistry
Composition and its percentage by weight：C：0.15～0.60%, Si：0.01～0.70%, Mn：1.00～6.00%, Al：3.0～
6.0%, Cr：0.10～2.0%；P≤0.015%, S≤0.010%, N≤0.008%, remaining are Fe and inevitably miscellaneous
Matter, and the weight of Cr, Al and Si meets following relation：0.05≤Cr/(Al+Si)≤0.40.
2. the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to claim 1, it is characterised in that：Described
The chemical composition of steel also includes one or more element in V, Ti, Mo, Nb and Zr.
3. the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to claim 2, it is characterised in that：Described
Steel also includes following chemical composition and its percentage by weight：V：0.01～0.20%, Ti：0.03～0.30%, Mo：0.10～
0.50%, Nb：0.02～0.20%, Zr：0.001～0.10%, and the weight satisfaction of Cr, V, Ti, Mo, Nb, Zr, Al and Si is such as
Lower relation：0.05≤(Cr+V+Ti+Mo+Nb+Zr)/(Al+Si)≤0.40.
4. the good high-strength and high ductility lightweight steel of 780MPa level cold-forming properties according to claim 1 or 2 or 3, its feature exist
In：The steel also includes following chemical composition and its percentage by weight：Ni：0.01～1.00%, Cu：0.01～2.0%, Ca：
0.0001～0.10%.
5. the good high-strength and high ductility lightweight steel of 780MPa level cold-forming properties according to claim 1 or 2 or 3, its feature exist
In：The weight of Cr, Al and Si meets following relation：0.05≤Cr/(Al+Si)≤0.25.
6. the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to Claims 2 or 3, it is characterised in that：
The weight of Cr, V, Ti, Mo, Nb, Zr, Al and Si meets following relation：0.05≤(Cr+V+Ti+Mo+Nb+Zr)/(Al+Si)≤
0.25.
7. the manufacture method of the good high-strength and high ductility lightweight steel of a kind of 780MPa levels cold-forming property, including smelting, continuous casting, plus
Heat, hot rolling, cooling are batched, and pickling is cold rolling, are annealed and coating step, it is characterised in that：In the continuous casting step, casting is adopted
Covering slag in Al2O3And SiO2Mass ratio Al2O3/SiO2≥1.0；In the heating stepses, slab heating rate is 5～50
DEG C/min, slab tapping temperature is 1050～1200 DEG C, and the heat time is 10～200min；In the hot-rolled step, hot rolling end
Roll 850～950 DEG C of temperature；In the cold rolling step, cold rolling reduction is 40～85%；In the annealing steps, using continuous
Annealing, continuous annealing soaking temperature are Tmin～900 DEG C, Tmin=(721-36*C-20*Mn+20*Al+23*Si+50*Cr) DEG C,
Soaking time is 20～300s, and after soaking, rapid cooling section begins to cool down temperature >=680 DEG C, cooldown rate >=5 DEG C/s.
8. the manufacture method of the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to claim 7, which is special
Levy and be：In the continuous casting step, using sheet blank continuous casting or slab CC machine, during using sheet blank continuous casting, slab enters furnace temperature
>=700 DEG C of degree, during using slab CC machine, carries out slow cooling using stay-warm case in slab cooling procedure, and cooldown rate≤50 DEG C/
Min, and slab charging temperature >=200 DEG C.
9. the manufacture method of the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to claim 7 or 8, its
It is characterised by：In the cooling step, quickly cooled down using leading portion, cooldown rate >=5 DEG C/s；Described batch in step, batch
Temperature is 550～650 DEG C.
10. the manufacture method of the good high-strength and high ductility lightweight steel of 780MPa levels cold-forming property according to claim 7 or 8,
It is characterized in that：In the annealing steps, dew point of atmosphere temperature≤- 20 DEG C, H is controlled2Volumetric concentration >=5%.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107326276A (en) * | 2017-06-19 | 2017-11-07 | 武汉钢铁有限公司 | A kind of 500 ~ 600MPa of tensile strength grades of hot rolling high-strength light dual phase steels and its manufacture method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101591751A (en) * | 2008-05-27 | 2009-12-02 | Posco公司 | Low-gravity high tensile steel plate and manufacture method thereof with good anti-wrinkling property |
| CN102409235A (en) * | 2010-09-21 | 2012-04-11 | 鞍钢股份有限公司 | High-strength cold-rolled phase-change induced plasticity steel plate and preparation method thereof |
| CN102912219A (en) * | 2012-10-23 | 2013-02-06 | 鞍钢股份有限公司 | TRIP steel plate with high product of strength and elongation and preparation method thereof |
| CN104928569A (en) * | 2015-06-30 | 2015-09-23 | 宝山钢铁股份有限公司 | 800MPa grade high-ductility low-density steel and manufacturing method thereof |
| CN105063311A (en) * | 2015-09-18 | 2015-11-18 | 东北大学 | Processing method for improving surface quality of TRIP steel |
| CN105960480A (en) * | 2014-02-03 | 2016-09-21 | 杰富意钢铁株式会社 | Alloyed hot-dip galvanized steel sheet and method for producing same |
-
2016
- 2016-10-26 CN CN201610949403.XA patent/CN106498307B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101591751A (en) * | 2008-05-27 | 2009-12-02 | Posco公司 | Low-gravity high tensile steel plate and manufacture method thereof with good anti-wrinkling property |
| CN102409235A (en) * | 2010-09-21 | 2012-04-11 | 鞍钢股份有限公司 | High-strength cold-rolled phase-change induced plasticity steel plate and preparation method thereof |
| CN102912219A (en) * | 2012-10-23 | 2013-02-06 | 鞍钢股份有限公司 | TRIP steel plate with high product of strength and elongation and preparation method thereof |
| CN105960480A (en) * | 2014-02-03 | 2016-09-21 | 杰富意钢铁株式会社 | Alloyed hot-dip galvanized steel sheet and method for producing same |
| CN104928569A (en) * | 2015-06-30 | 2015-09-23 | 宝山钢铁股份有限公司 | 800MPa grade high-ductility low-density steel and manufacturing method thereof |
| CN105063311A (en) * | 2015-09-18 | 2015-11-18 | 东北大学 | Processing method for improving surface quality of TRIP steel |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107326276A (en) * | 2017-06-19 | 2017-11-07 | 武汉钢铁有限公司 | A kind of 500 ~ 600MPa of tensile strength grades of hot rolling high-strength light dual phase steels and its manufacture method |
| CN107326276B (en) * | 2017-06-19 | 2019-06-07 | 武汉钢铁有限公司 | A kind of 500~600MPa of tensile strength grades of hot rolling high-strength light dual phase steels and its manufacturing method |
| CN107326282A (en) * | 2017-07-13 | 2017-11-07 | 武汉钢铁有限公司 | 600MPa grades of high-yield-ratio hot rolling high-strength light steel and its manufacture method |
| CN107326282B (en) * | 2017-07-13 | 2018-09-14 | 武汉钢铁有限公司 | 600MPa grades of high-yield-ratio hot rolling high-strength light steel and its manufacturing method |
| CN109929982A (en) * | 2019-03-19 | 2019-06-25 | 首钢集团有限公司 | Production method of high-strength steel |
| CN111020367A (en) * | 2019-10-28 | 2020-04-17 | 鞍钢股份有限公司 | Cold-rolled high-strength light steel and preparation method thereof |
| CN111020367B (en) * | 2019-10-28 | 2021-04-27 | 鞍钢股份有限公司 | Cold-rolled high-strength light steel and preparation method thereof |
| CN113355590A (en) * | 2020-03-06 | 2021-09-07 | 宝山钢铁股份有限公司 | Three-layer composite structure high-strength steel plate and manufacturing method thereof |
| CN114807755A (en) * | 2022-04-15 | 2022-07-29 | 马鞍山钢铁股份有限公司 | High-strength and high-toughness pre-coated steel plate with good coating quality, preparation method of high-strength and high-toughness pre-coated steel plate, steel member and application of steel member |
| CN114807755B (en) * | 2022-04-15 | 2024-03-26 | 马鞍山钢铁股份有限公司 | High-strength and high-toughness pre-coated steel plate with good coating quality, preparation method thereof, steel member and application thereof |
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