CN109913763A - The good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties and its manufacturing method - Google Patents
The good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties and its manufacturing method Download PDFInfo
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Abstract
The invention discloses a kind of good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming property and its manufacturing methods, belong to iron and steel smelting technology field.According to mass percent meter, it includes following chemical constituent: C:0.13~0.22, Mn:1.20~1.70, Si:0.20~0.50, Als:0.30~0.80, P≤0.015, S≤0.0010, N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:0.0005~0.0025, T [O]≤0.002, remaining is Fe and inevitable impurity；And 0.50≤Si+Als≤1.00.And it experience steel-making, LF refining, RH refining, continuous casting, hot rolling, cooling, batches, pickling, cold rolling, annealing and flattening process；The application is on the basis of selecting the design of lower alloying element content, in conjunction with rolling and cooling technique, so that the product of preparation is on the basis of having preferable intensity and clod wash, it is of less demanding to production technology producing line.
Description
Technical field
The present invention relates to a kind of cold-rolled biphase steels, belong to iron and steel smelting technology field, more particularly to 1000MPa grades a kind of
The good inexpensive cold-rolled biphase steel of cold-forming property and its manufacturing method.
Background technique
In recent years, in order to reduce the energy consumption in automobile use process, CO is reduced2Discharge, automobile steel is just towards high-strength height
Tough direction is developed, and 1000MPa grades or more of super-high strength steel is one of its main direction of development, and dual phase steel is due to having height
Preliminary work hardening rate and processability, therefore the strong dual phase steel of 1000MPa or more rank superelevation is used widely.
As Chinese invention patent application (application publication number: CN105803321A applies for publication date: 2016-07-27) is open
A kind of 980MPa grades of ultra-fine grain containing vanadium cold-rolled biphase steel and preparation method thereof, is made of following weight percent composition: C:
0.10~0.20%, Si:0.30~1.00%, Mn:1.50~2.50%, Cr:0.20~0.80%, Al:0.01~0.06%,
V:0.05~0.15%, P≤0.020%, S≤0.015%, N≤0.006%；Surplus is Fe and inevitable impurity.The present invention
Come fining ferrite and martensitic crystal grains with trace V, while VC disperse educt plays the effect of precipitation strength, and is substantially reduced life
Cost is produced, cold-rolled biphase steel mechanical property prepared by the present invention, forming property and welding performance are excellent, and cost advantage is obvious, tool
There are significant economic benefit and social benefit.
For another example Chinese invention patent application (application publication number: CN107058869A applies for publication date: 2017-08-18) is public
Ultralow yield tensile ratio 980MPa grades of cold-rolled biphase steels and its manufacturing method are opened, chemical component is in percentage by weight are as follows: C:
0.13~0.18%, Si:0.3~0.6%, Mn:1.7~2.4%, Als:0.03~0.06%, Nb:0~0.05%, Cr:0.3
~0.5%, remaining is Fe and other inevitable impurity.It is considered as in ingredient design based on phase transformation strengthening, in conjunction with solid
Molten reinforcing, refined crystalline strengthening, phase transformation strengthening, precipitation strength complex intensifying mode, which can be used as automobile collision preventing
Part, structural member and interior plate material.The advantage is that DP980 of the invention have ultralow yield tensile ratio, good percentage elongation, higher n value,
The performance characteristics such as Mechanical Fluctuation range is small, work department skill sensibility is low, the rebound after capable of reducing punching press are conducive to subsequent vapour
The deep processing of garage's industry.Above-mentioned 2 applications do not require the performance indicators such as clod wash and hole expansibility, therefore, to some mouldabilities
The more demanding part of energy, these products are not met by requirement.
For another example Chinese invention patent application (application publication number: CN107043888A applies for publication date: 2017-08-15) is public
A kind of 980MPa that cold-bending property is excellent grade dual-phase steel plate and preparation method thereof, chemical component and weight percent are opened
Than are as follows: C:0.10~0.12%；Si:0.45~0.65%；Mn:2.4~2.6%；Cr:0.35~0.45%；Nb:0.05~
0.075%；Ti:0.06~0.10%；Als:0.055~0.075%；P≤0.008%；S≤0.002%；N≤0.003%,
Surplus is Fe and inevitable impurity.Pass through smelting, LF refining and RH refining, hot continuous rolling, pickling and cold-rolling, continuous annealing process
Martensite+ferritic structure dual phase sheet steel is obtained, grain size number has excellent mechanical property up to 12 grades or more
Can, yield strength is 810MPa~850MPa, and tensile strength is in 980MPa or more, 10~20%, 180 ° of clod washes of elongation percentage
Energy≤2a, a are plate thickness, and have the characteristics that advantage of lower cost, products application performance are good.Although in the performance indicator of this application
Including clod wash and hole expansibility etc. indexs, but to some drawings and the higher components of bending property, plasticity and cold-bending property
Still it cannot meet the requirements, and be added to the alloying elements such as higher Si, Mn, Nb, Ti in the design of its ingredient, on the one hand cause
Its cost of alloy is higher, on the other hand in process of production, continuous casting and rolling difficulty it is big, need Special high-strength steel producing line into
Row production.
In short, current techniques using higher carbon content produce 1000MPa grades of dual phase steels when, when using higher carbon content,
Alloying element addition is relatively fewer, and tensile strength can reach 1000MPa or more, but cannot obtain preferable clod wash and reaming simultaneously
The performances such as rate, these products are not able to satisfy the part demand more demanding to processability, and produce using compared with low carbon content
When 1000MPa grades of steel, to make product obtain preferable intensity/elongation percentage and clod wash and hole expansibility etc., need to be added in steel compared with
High alloying element, but on the one hand the addition of alloying element increases cost of alloy, cause cost of alloy higher, on the other hand lead
Production process difficulty is caused to increase, it is difficult to produce in general producing line.
Summary of the invention
In order to solve the above technical problems, the present invention provides a kind of good low cost of 1000MPa grades of cold-forming property is cold
Roll dual phase steel and its manufacturing method.Select lower alloying element content design on the basis of, in conjunction with rolling and cooling technique,
So that the product of preparation is on the basis of having preferable intensity and clod wash, it is of less demanding to production technology producing line.
To achieve the above object, the invention discloses a kind of good inexpensive cold rolling of 1000MPa grades of cold-forming property is double
Xiang Gang, according to mass percent meter, it includes following chemical constituent:
C:0.13~0.22, Mn:1.20~1.70, Si:0.20~0.50, Als:0.30~0.80, P≤0.015, S≤
0.0010, N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:0.0005~0.0025, T [O]≤0.002,
Remaining is Fe and inevitable impurity；
And 0.50≤Si+Als≤1.00.
Further, according to mass percent meter, it includes following chemical constituent:
C:0.15~0.20, Mn:1.20~1.70, Si:0.20~0.50, Als:0.40~0.80,0.005≤P≤
0.015,0.0001≤S≤0.0010,0.001≤N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:
0.0005~0.0025, T [O]≤0.002, remaining is Fe and inevitable impurity；
And 0.50≤Si+Als≤0.80.
Further, according to mass percent meter, it includes following chemical constituent:
C:0.15~0.20, Mn:1.20~1.70, Si:0.20~0.50, Als:0.40~0.80,0.005≤P≤
0.015,0.0001≤S≤0.0010,0.001≤N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:
0.0005~0.0025,0.001≤T [O]≤0.002, remaining is Fe and inevitable impurity；
And 0.60≤Si+Als≤0.80.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.131, Mn:1.50, Si:0.30, Als:0.50, P:0.008, S:0.0008, N:0.003, Cr:0.38, Nb:
0.030, Ca:0.0008, T [O]: 0.0012, remaining is Fe and inevitable impurity；
And Si+Als:0.80.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.18, Mn:1.60, Si:0.30, Als:0.30, P:0.012, S:0.0005, N:0.0035, Cr:0.50, Nb:
0.012, Ca:0.0012, T [O]: 0.0013, remaining is Fe and inevitable impurity；
And Si+Als:0.55.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.14, Mn:1.65, Si:0.45, Als:0.42, P:0.010, S:0.0003, N:0.004, Cr:0.30, Nb:
0.042, Ca:0.0009, T [O]: 0.0015, remaining is Fe and inevitable impurity；
And Si+Als:0.87.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.19, Mn:1.30, Si:0.21, Als:0.70, P:0.008, S:0.0005, N:0.003, Cr:0.35, Nb:
0.016, Ca:0.0015, T [O]: 0.0017, remaining is Fe and inevitable impurity；
And Si+Als:0.91.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.21, Mn:1.55, Si:0.26, Als:0.60, P:0.0056, S:0.0007, N:0.0035, Cr:0.46,
Nb:0.015, Ca:0.0013, T [O]: 0.0010, remaining is Fe and inevitable impurity；
And Si+Als:0.72.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.20, Mn:1.21, Si:0.22, Als:0.78, P:0.006, S:0.0004, N:0.0025, Cr:0.48, Nb:
0.012, Ca:0.0018, T [O]: 0.0016, remaining is Fe and inevitable impurity；
And Si+Als:0.70.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.16, Mn:1.35, Si:0.40, Als:0.35, P:0.013, S:0.0005, N:0.0025, Cr:0.42, Nb:
0.030, Ca:0.0016, T [O]: 0.0018, remaining is Fe and inevitable impurity；
And Si+Als:0.75.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.15, Mn:1.40, Si:0.36, Als:0.64, P:0.008, S:0.0002, N:0.0035, Cr:0.32, Nb:
0.015, Ca:0.0020, T [O]: 0.0014, remaining is Fe and inevitable impurity；
And Si+Als:1.00.
Preferably, according to mass percent meter, it includes following chemical constituent:
C:0.17, Mn:1.45, Si:0.49, Als:0.51, P:0.014, S:0.0003, N:0.0032, Cr:0.36, Nb:
0.030, Ca:0.0002, T [O]: 0.0012, remaining is Fe and inevitable impurity；
And Si+Als:1.00.
Further, the microstructure of the cold-rolled biphase steel is constituted by three layers of upper, middle and lower in a thickness direction, it is described on
In layer and the tissue of lower layer, ferrite accounting >=95%, thickness is respectively 1~50 μm；The middle layer is plain by 40~80% iron
Body and 20~60% martensite constitute.Wherein, ferrite content control is in suitable range, to final cold-bending property
It is more advantageous；
Preferably, the microstructure of the cold-rolled biphase steel is constituted by three layers of upper, middle and lower in a thickness direction, the upper layer
In the tissue of lower layer, 95%≤ferrite accounting≤98%, thickness is respectively 5~35 μm；The middle layer is by 50~70%
Ferrite and 30~50% martensite constitute.
Preferably, the crystallite dimension of the ferritic structure is less than 3um.
Preferably, the crystallite dimension of the ferritic structure is less than 3um, and is greater than 1um.
Further, the cold-rolled biphase steel tensile strength that the present invention obtains reaches 1000MPa or more.
Preferably, the cold-rolled biphase steel tensile strength is more than or equal to 1000MPa, and is less than or equal to 1200MPa.
Further, the cold rolling two-phase yield strength that the present invention obtains is 550~750MPa.
Preferably, the cold rolling two-phase yield strength that the present invention obtains is 550~700MPa.
Further, cold-rolled biphase steel elongation percentage A80 >=16% that the present invention obtains；
Preferably, cold-rolled biphase steel elongation percentage 16.0%≤A80≤25.0% that the present invention obtains.
Further, the cold-rolled biphase steel hole expansibility that the present invention obtains is 20%~70%.
Preferably, the cold-rolled biphase steel hole expansibility that the present invention obtains is 40~50%.
Further, clod wash intensity of the cold-rolled biphase steel that the present invention obtains under 180 ° is 0.3a~1.5a.
Preferably, clod wash intensity of the cold-rolled biphase steel that the present invention obtains under 180 ° is 0.5a.
Preferably, clod wash intensity of the cold-rolled biphase steel that the present invention obtains under 180 ° is 1.0a.
In order to preferably realize technical purpose of the invention, the invention also discloses a kind of above-mentioned 1000MPa grades of cold working
It is of good performance low cost cold-rolled biphase steel preparation method, it include steel-making, LF refining, RH refining, continuous casting, hot rolling, cooling,
It batches, pickling, cold rolling, annealing and flattening process；Wherein, the S content in steel can be effectively reduced using LF refining, reduces in steel
Sulfide content, promote the toughness of product；The harmful elements content such as N, H in steel can be reduced using RH vacuum, reduced in steel
Nitride, gas content improve the toughness of product；
1) hot rolling: including first roughing finish rolling again, roughing temperature >=950 DEG C, roughing reduction ratio >=80%；The finish rolling
Temperature is between 800~900 DEG C, finish rolling reduction ratio >=95%, obtains hot rolling product with a thickness of 1.0~2.5mm；
2) cooling: including slow cooling, etc. mild rapid cooling, and slow cooling cooling rate≤20 DEG C/s, isothermal temperature are 680~750
DEG C, isothermal time is 5~20s, rapid cooling cooling rate >=50 DEG C/s；
3) batch: the coiling temperature is 100~300 DEG C；
4) cold rolling: cold rolling reduction ratio is 30~60%, obtains cold-rolled products with a thickness of 0.5~1.5mm；
5) anneal: including strip heating, soaking, slow cooling, rapid cooling and Wetted constructures, and soaking temperature is 760~830
DEG C, 30~200s of soaking time；Slow cooling final temperature is 620~700 DEG C, slow cooling rate≤15 DEG C/s, rapid cooling rate >=50 DEG C/
s；Overaging temperature is 200~300 DEG C；
6) smooth: to use finishing, the finishing reduction ratio is 0.3~1.0%, controls dew point -20~-50 in annealing furnace
DEG C, hydrogen content is 1~20% in furnace, residual 1~30ppm of oxygen.
Further, in the hot rolling technology, 950 DEG C≤roughing temperature≤1000 DEG C, 80%≤roughing reduction ratio≤
95%；Final rolling temperature is between 830~880 DEG C, 95%≤finish rolling reduction ratio≤98%.
This is because rolling equipment rolling load increases if roughing temperature is too low, steel strip shape quality is deteriorated；With this
Meanwhile roughing reduction ratio can not control too low, be otherwise unfavorable for crystal grain refinement, cause organizational coarseness, reduce the strong of product
Degree and toughness.And if finishing temperature is too low in finishing stands, it is easy to form non-uniform tissue in steel, and upper and lower surface layer
Ferrite content in tissue reduces, unfavorable to final cold-bending property, and hot rolling is difficult, and finishing temperature too Gao Rongyi
Coarse grain structure is formed, and the ferrite content in upper and lower surface layer tissue increases, and is unfavorable for improving the intensity of product,
And finish rolling reduction ratio is too low, is unfavorable for crystal grain refinement, easily forms coarse grain structure, and hot fine rolling reduction ratio is too low, heat
It is too thick to roll product, so that cold rolling reduction ratio increases, cold rolling process rolling is difficult, is not easy to manufacture.Therefore it is preferred that 950 DEG C≤roughing temperature
≤ 1000 DEG C, 80%≤roughing reduction ratio≤95%；Final rolling temperature between 830~880 DEG C, 95%≤finish rolling reduction ratio≤
98%.
Further, in the cooling technique, 10 DEG C/s≤slow cooling cooling rate≤20 DEG C/s, isothermal temperature be 700~
730 DEG C, isothermal time be 8~15s, 50 DEG C/s≤rapid cooling cooling rate≤75 DEG C/s.
The cooling technique using slow cooling, etc. mild three sections of rapid cooling, wherein the temperature setting of slow cooling section and isothermal section can make
A certain amount of ferrite is generated in hot-rolled product tissue, is conducive to the rolling that acid rolls process.The cooling of rapid cooling section can make to keep away in steel
Exempt to generate coarse pearlite, bainite structure, is conducive to refine continuous annealing tissue.Therefore it is preferred that 10 DEG C/s≤slow cooling cooling rate≤
20 DEG C/s, isothermal temperature be 700~730 DEG C, isothermal time be 8~15s, 50 DEG C/s≤rapid cooling cooling rate≤75 DEG C/s.
The coiling technique, coiling temperature too high coarse tissue and carbide easy to form are unfavorable for refining steel
Crystal grain.Coiling temperature is too low, and the tissue of steel cannot be replied, and cause raw material really up to the mark, is unfavorable for acid and rolls rolling.
And during acid rolls, cold rolling reduction ratio is too low, the tissue in steel cannot be sufficiently refined, and cold rolling reduction ratio is too high
Then roll difficulty, and strip is easy to the problems such as generating edge crack, therefore it is preferred that cold rolling reduction ratio is 30~60%, obtain cold rolling production
Product are with a thickness of 0.5~1.5mm.
Further, in the annealing process, soaking temperature is 780~820 DEG C, and slow cooling final temperature is 650~680
DEG C, 10 DEG C/s≤slow cooling rate≤15 DEG C/s, 50 DEG C/s≤rapid cooling rate≤70 DEG C/s.
Soaking temperature of the invention is too high, and ferrite thickness increases in upper and lower layer tissue, reduces the intensity of steel, temperature is too
Low, the ferrite content in upper and lower layer tissue is relatively low, reduces the cold-bending property of material.Therefore it is preferred that soaking temperature is 780~820
℃。
In order to make ferrite in steel product tissue and ratio of martensite meet requirement of the invention, the present invention is preferably slow
Cold final temperature is 650~680 DEG C, 10 DEG C/s≤slow cooling rate≤15 DEG C/s, 50 DEG C/s≤rapid cooling rate≤70 DEG C/s.
Further, in the flattening process, the finishing reduction ratio is 0.5~0.8%, controls dew point-in annealing furnace
20~-40 DEG C, hydrogen content is 5~15% in furnace, residual 1~20ppm of oxygen.
The present invention needs to control in annealing furnace hydrogen content etc. in dew point and furnace, is easy to make because dew point is too high in annealing furnace
It is too thick at upper and lower surface layer ferrite thickness, reduce intensity；And dew point is too low, then the ferrite content in layer tissue is not up and down
Foot, to reduce the hole expansibility and cold-bending property and extension property of product.And hydrogen content is too low, be easy to cause upper and lower surface
Layer ferrite thickness is too thick, reduction intensity, and H2Content is too high, then the ferrite content up and down in layer tissue is insufficient, to drop
The hole expansibility and cold-bending property and extension property of low product.Residual oxygen content is too high, be easy to cause upper and lower surface layer ferrite thick
Too thick, reduction intensity is spent, and residual oxygen content is too low, then the ferrite content up and down in layer tissue is insufficient, to reduce product
Hole expansibility and cold-bending property and extension property.
Each alloying element of the present invention and the choosing principles of content are as follows:
Carbon (C): being to improve the most effective and cheap addition element of steel strength, the tensile strength of the increase steel of carbon content with
Yield strength increases accordingly, but elongation percentage and impact toughness decreased, and corrosion resistance can also decline, and the sweating heat shadow of steel
Ringing area there is also phenomenon of hardening, and lead to the generation of welding cold cracking.Carbon content is too low, for the intensity for guaranteeing steel, needs to increase
Add the alloying elements such as Mn, Si, Cr, Nb, Ti in steel, to increase cost of alloy, carbon content is too high, is easy to make steel surface layer
Martensite content increases, so that surface is hardened, local plastic is reduced, and crizzle is easily generated in clod wash, to reduce
The cold-bending property of steel, therefore, C content of the invention are preferably 0.15~0.20%.
Silicon (Si): may advantageously facilitate steel surface and form ferritic structure, improve the toughness and cold-bending property of steel, and
Si can play the role of reducing S content in steel, reduce the sulphide inculsion in steel, to improve steel clod wash and hole expansibility
Effect, Si can also improve the corrosion resistance of steel, stainless steel, low-alloy steel are often added to, in corrosion resistant alloy, to improve these
The corrosion resistance of alloy, having them, resistance to chloride stress-corrosion cracking, resistance to spot corrosion, resistance to hot concentrated burn into is anti-oxidant, resistance to sea
The performances such as aqueous corrosion.Si can also improve the corrosion resistance of low-alloy steel splash zone in the seawater, but Si content is too high, promotes upper following table
Face ferrite intensity is too high, reduces cold-bending property, therefore, Si content of the invention is preferably 0.20~0.50%.
Manganese (Mn): being important Strengthening and Toughening element, and with the increase of Mn content, the intensity of steel is obviously increased, and impacts and turn
Temperature hardly happens variation, and tensile strength 100MPa about can be improved in the Mn containing 1%, meanwhile, Mn slightly improves the resistance to of steel
Corrosive nature, but Mn content height dramatically increases the cost of alloy of steel, and Mn also promotes to form more hard phase in the layer tissue of surface
The serious segregation of martensite and center leads to cold bend cracking, and Mn is also easy to form the complicated carbide of FeMnCr in steel, to steel
The reaming performance of material has an adverse effect, and Mn content of the invention is preferably 1.20~1.70%.
Phosphorus (P), sulphur (S) are the impurity elements in steel, and P has the corrosion resistance effect that improves, but P is that one kind is easy to
The element of segregation generates macrosegregation in the part of steel, reduces plasticity and toughness, highly unwanted to low-temperature flexibility, S element is in steel
In be easy to be segregated and be enriched with, be the element to corrosion resistance evil, pass through the Si and Al content and steelmaker controlled in steel
Skill can control S 0.001 hereinafter, therefore controlling 0.005≤P≤0.015%, 0.0001%≤S≤0.0010%.
Nitrogen (N): N is the impurity element in steel, is easy to Al, Nb, Ti in steel etc. and forms nitride, on the one hand suitable nitrogen
Intensity just now can be improved in compound, but then, the too high coarse nitride easy to form of nitrogen content, to reduce steel
Hole expansibility and cold-bending property, therefore its content is reduced as far as possible, therefore controls 0.001%≤N≤0.004%.
Als:Al may advantageously facilitate steel surface and form ferritic structure, and Al can play the work for reducing S content in steel
With, the sulphide inculsion in steel is reduced, so that the effect of steel toughness is improved, but Al content is too high, upper and lower surface layer ferrite
Thickness is too thick, and intensity is caused to decline, in addition, Al easily easily forms coarse nitride/sulfide and oxygen with nitrogen, sulphur, the oxygen in steel
The inclusion particles such as compound, the clod wash and reaming performance of steel are reduced, therefore Al content is 0.40~0.80% in the present invention.
Niobium (Nb) is two kinds of strong carbide and nitride forming element, has extremely strong affinity with nitrogen, carbon, can be therewith
Form extremely stable carbonitride.The carbonitride Second Phase Particles of the Nb of Dispersed precipitate, can along the distribution of austenite grain boundary
Original austenite grains Coarsening Temperature is greatly improved, in austenite recrystallization temperature region during the rolling process, the carbon nitrogen of Nb
Changing precipitate can be used as the forming core core of austenite grain, and within the scope of non-recrystallization temperature, the carbon of the Nb of Dispersed precipitate
Nitrogenizing precipitate can prevent austenite grain from further growing up with effectively pin austenite grain boundary, thus fining ferrite grains,
Achieve the purpose that improve intensity and impact flexibility；It therefore, can by the refined crystalline strengthening and precipitation enhancement of Nb microalloy element
So that steel plate obtains excellent obdurability.The present invention controls Nb:0.010~0.050%.
Chromium (Cr): can significantly improve the antioxidation of steel, increase the resistance to corrosion of steel, meanwhile, with chromium content
Increase, the tensile strength and hardness of alloy also can significantly rise, the present invention comprehensively consider the corrosion-resistant of steel, impact flexibility and
Cost of alloy, but Cr content is too high, and Fe, Mn and C in Yi Yugang generate the carbide of complicated FeMnCr, the reaming to steel
Performance has an adverse effect, therefore the present invention controls Cr:0.20~0.50%.
Calcium (Ca): Ca can make the reduction of steel inclusion fusing point, so that field trash be made to remove in the steel-making stage, and be conducive to change
Become the shape of field trash, reduces the pointed formation being mingled with, but Ca content is too high, will increase the amount of steel inclusion, therefore this hair
0.0005~0.0025% in bright.
T [O]: the high oxidation easy to form of content is field trash, therefore should reduce the content of T in steel [O], T [O] in the present invention
≤ 0.002%.
Si+Als:0.50%≤Si+Als≤0.80%, according to test result, Si+Als control is advantageous in the scope of the invention
In the S content reduced in steel and obtain the heterogeneous microstructure of product of the present invention.
The beneficial effects are mainly reflected as follows following aspects:
1, cold-rolled biphase steel tensile strength prepared by the present invention be more than or equal to 1000MPa, yield strength be 550~
750MPa；Meanwhile elongation percentage A80 >=16%, hole expansibility are 20%~70%；Clod wash intensity under 180 ° be 0.3a~
1.5a；Therefore dual phase steel produced by the present invention has preferable mechanical property, plasticity and cold-bending property, meanwhile, product surface quality
Well, welding performance is good.
2, not only alloy content is few for the obtained dual phase steel for having above-mentioned superperformance of the present invention, but also pushes in sour roll process
Lower rate is low, easily fabricated, the producing line for being suitble to rolling equipment ability not high.
Specific embodiment
In order to better explain the present invention, below in conjunction with the specific embodiment main contents that the present invention is furture elucidated, but
The contents of the present invention are not limited solely to following embodiment.
The invention discloses a kind of preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming property,
Wherein, it is smelted using the alloying element that table 1 designs；
1 various embodiments of the present invention of table and comparative example main component list
In above-mentioned table 1,10 and 11 be the ingredient of comparative example, C, Si of comparative example 10, Als, (Si+Als), Mn and T
[O] not in the scope of the invention, Si, Als of comparative example 11, (Si+Als), Mn, Nb, S, Ca and T [O] be not in model of the present invention
It encloses.
Cold-rolled biphase steel of the invention includes steel-making, LF refining, RH refining, continuous casting, hot rolling, cooling, batches, is pickling, cold
It rolls, anneal and flattening process；Wherein main technologic parameters are as shown in table 2 and table 3；
2 technological parameter list (one) of table
In table 2, finish rolling finishing temperature, section cooling isothermal time and the rapid cooling rate and coiling temperature of comparative example 3-2
Not in the scope of the invention, the hot fine rolling reduction ratio of comparative example 3-3 and 3-4, slow cooling rate, section cooling isothermal temperature be not at this
The cold rolling reduction ratio of invention scope, 3-4 is too high.Two comparative examples of 3-3 and 3-4 due to hot rolling and cold-rolling process state modulator not
Rationally cold rolling is caused to be cracked, causes product manufacturing difficult.The fabrication process parameters of other embodiments are in the scope of the invention.
3 technological parameter list (two) of table
In table 3, above-mentioned comparative example and embodiment use continuous annealing, and the continuous annealing soaking temperature of comparative example 1-2 is higher than
The soaking temperature of example of the present invention, comparative example 1-3 is too low, and slow cooling final temperature is relatively low, and the soaking time of comparative example 1-4 is too long, dew
Point and residual oxygen content etc. are higher.
Cold-rolled biphase steel obtained by above-described embodiment and comparative example is tested for the property, list shown in table 4 is obtained.
4 dual phase steel capabilities list of table
By above-mentioned list it is found that comparative example 1-2,1-3 and 1-4 cause since continuous annealing process parameter is not in the scope of the invention
Ratio of ferrite is relatively low in layer tissue above and below product or thickness is partially thick and ferrite crystal grain is coarse, leads to final low strength,
Elongation percentage and hole expansibility are relatively low, and cold-bending property is bad.Comparative example 3-2 does not cause to produce due to hot-rolled process parameter in the scope of the invention
Product ferrite crystal grain is coarse, and product strength, reaming, cold-bending property are relatively low.Comparative example 10 is since the Si+Als in ingredient is lower than this
Invention, and Mn content is higher than the present invention, therefore the ferrite in layer tissue will be lower than the present invention up and down, and due to Si, Al content
Low, the S in ingredient is also higher, causes its hole expansibility and cold-bending property poor, and comparative example 11 causes since its Mn content is higher
Ferrite content in its textura epidermoidea is relatively low, and then has an adverse effect to its cold-bending property, and in addition its S content and T [O] contain
Ca that is higher, and being not added with certain is measured, causes its field trash more, hole expansibility is lower.
Above embodiments are only best citing, rather than a limitation of the embodiments of the present invention.Except above-described embodiment
Outside, there are also other embodiments by the present invention.All technical solutions formed using equivalent substitution or equivalent transformation, all fall within the present invention
It is required that protection scope.
Claims (9)
1. a kind of good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming property, according to mass percent meter, it includes such as
Lower chemical constituent:
C:0.13~0.22, Mn:1.20~1.70, Si:0.20~0.50, Als:0.30~0.80, P≤0.015, S≤
0.0010, N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:0.0005~0.0025, T [O]≤0.002,
Remaining is Fe and inevitable impurity；
And 0.50≤Si+Als≤1.00.
2. the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties according to claim 1, it is characterised in that:
According to mass percent meter, it includes following chemical constituent:
C:0.15~0.20, Mn:1.20~1.70, Si:0.20~0.50, Als:0.40~0.80,0.005≤P≤0.015,
0.0001≤S≤0.0010,0.001≤N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:0.0005~
0.0025, T [O]≤0.002, remaining is Fe and inevitable impurity；
And 0.50≤Si+Als≤0.80.
3. the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming property according to claim 1 or claim 2, feature exist
In: according to mass percent meter, it includes following chemical constituent:
C:0.15~0.20, Mn:1.20~1.70, Si:0.20~0.50, Als:0.40~0.80,0.005≤P≤0.015,
0.0001≤S≤0.0010,0.001≤N≤0.004, Cr:0.20~0.50, Nb:0.010~0.05, Ca:0.0005~
0.0025,0.001≤T [O]≤0.002, remaining is Fe and inevitable impurity；
And 0.60≤Si+Als≤0.80.
4. the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming property according to claim 1 or claim 2, feature exist
In: the microstructure of the cold-rolled biphase steel is constituted by three layers of upper, middle and lower in a thickness direction, the tissue of the upper and lower
In, ferrite accounting >=95%, thickness is respectively 1~50 μm；The middle layer is by 40~80% ferrite and 20~60%
Martensite is constituted.
5. the preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa described in a kind of claim 1 grades of cold-forming property, it
Including steel-making, LF refining, RH refining, continuous casting, hot rolling, cooling, batch, pickling, cold rolling, annealing and flattening process；
1) hot rolling: including first roughing finish rolling again, roughing temperature >=950 DEG C, roughing reduction ratio >=80%；The final rolling temperature
Between 800~900 DEG C, finish rolling reduction ratio >=95% obtains hot rolling product with a thickness of 1.0~2.5mm；
2) cooling: including slow cooling, etc. mild rapid cooling, and slow cooling cooling rate≤20 DEG C/s, isothermal temperature are 680~750 DEG C, etc.
The warm time is 5~20s, rapid cooling cooling rate >=50 DEG C/s；
3) batch: the coiling temperature is 100~300 DEG C；
4) cold rolling: cold rolling reduction ratio is 30~60%, obtains cold-rolled products with a thickness of 0.5~1.5mm；
5) anneal: including strip heating, soaking, slow cooling, rapid cooling and Wetted constructures, and soaking temperature is 760~830 DEG C,
Hot 30~200s of time；Slow cooling final temperature is 620~700 DEG C, slow cooling rate≤15 DEG C/s, rapid cooling rate >=50 DEG C/s；It crosses
Aging temp is 200~300 DEG C；
6) smooth: to use finishing, the finishing reduction ratio is 0.3~1.0%, controls dew point -20~-50 DEG C in annealing furnace, furnace
Interior hydrogen content is 1~20%, residual 1~30ppm of oxygen.
6. the preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties according to claim 5,
It is characterized in that: in the hot rolling technology, 950 DEG C≤roughing temperature≤1000 DEG C, 80%≤roughing reduction ratio≤95%；Finish rolling temperature
Degree is between 830~880 DEG C, 95%≤finish rolling reduction ratio≤98%.
7. the preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties according to claim 5,
Be characterized in that: in the cooling technique, 10 DEG C/s≤slow cooling cooling rate≤20 DEG C/s, isothermal temperature is 700~730 DEG C, etc.
The warm time be 8~15s, 50 DEG C/s≤rapid cooling cooling rate≤75 DEG C/s.
8. the preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties according to claim 5,
Be characterized in that: in the annealing process, soaking temperature is 780~820 DEG C, and slow cooling final temperature is 650~680 DEG C, 10 DEG C/s
≤ slow cooling rate≤15 DEG C/s, 50 DEG C/s≤rapid cooling rate≤70 DEG C/s.
9. the preparation method of the good inexpensive cold-rolled biphase steel of 1000MPa grades of cold-forming properties according to claim 5,
Be characterized in that: in the flattening process, the finishing reduction ratio is 0.5~0.8%, controls dew point -20~-40 in annealing furnace
DEG C, hydrogen content is 5~15% in furnace, residual 1~20ppm of oxygen.
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| CN111500935B (en) * | 2020-06-09 | 2021-10-26 | 首钢集团有限公司 | 1000 MPa-grade high-strength steel and preparation method and application thereof |
| CN112281062A (en) * | 2020-10-22 | 2021-01-29 | 本钢板材股份有限公司 | 1000 MPa-grade low-cost hot-galvanized dual-phase steel and preparation method thereof |
| CN113308649A (en) * | 2021-05-14 | 2021-08-27 | 唐山钢铁集团有限责任公司 | Low-yield-ratio 1000 MPa-grade cold-rolled dual-phase strip steel and production method thereof |
| CN113684427A (en) * | 2021-08-13 | 2021-11-23 | 北京首钢冷轧薄板有限公司 | 800 MPa-grade dual-phase steel with excellent bulging capacity and preparation method thereof |
| CN115522131A (en) * | 2022-10-13 | 2022-12-27 | 武汉科技大学 | 1000 MPa-grade hot-rolled dual-phase steel and preparation method and application thereof |
| CN115522131B (en) * | 2022-10-13 | 2023-12-05 | 武汉科技大学 | 1000 MPa-grade hot-rolled dual-phase steel and preparation method and application thereof |
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