CN107338395B - 450MPa grades of hot rolling low yield strength ratio paper-thin strips and its manufacturing method - Google Patents
450MPa grades of hot rolling low yield strength ratio paper-thin strips and its manufacturing method Download PDFInfo
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- CN107338395B CN107338395B CN201710571164.3A CN201710571164A CN107338395B CN 107338395 B CN107338395 B CN 107338395B CN 201710571164 A CN201710571164 A CN 201710571164A CN 107338395 B CN107338395 B CN 107338395B
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- 238000005098 hot rolling Methods 0.000 title claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 title claims description 38
- 238000001816 cooling Methods 0.000 claims abstract description 60
- 238000005096 rolling process Methods 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 49
- 239000010959 steel Substances 0.000 claims description 49
- 238000010438 heat treatment Methods 0.000 claims description 25
- 238000009749 continuous casting Methods 0.000 claims description 15
- 230000009467 reduction Effects 0.000 claims description 8
- 229910000734 martensite Inorganic materials 0.000 claims description 7
- 238000007670 refining Methods 0.000 claims description 7
- 238000003723 Smelting Methods 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 description 10
- 238000005728 strengthening Methods 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- 229910001566 austenite Inorganic materials 0.000 description 7
- 239000013078 crystal Substances 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 239000004615 ingredient Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 238000005097 cold rolling Methods 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 229910000885 Dual-phase steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
The present invention provides a kind of 450MPa grades of hot rolling low yield strength ratio paper-thin strips, its chemical component is by mass percentage are as follows: C:0.01~0.05%, Si≤0.05%, Mn:0.8%~1.5%, Cr:0.05%~0.6%, Als:0.015%~0.10%, P≤0.010%, S≤0.006%, N≤0.006%, Ti≤0.010%, surplus are Fe and inevitable impurity.The process that the present invention is heated by the way that intermediate base is arranged among roughing and finish rolling, and the cooling condition for controlling section cooling, produces paper-thin strip using hot rolling technology, and not only thickness is minimum can achieve 0.8mm, and yield tensile ratio 0.5 hereinafter, have very strong practicability.
Description
Technical field
The present invention relates to the manufacturing fields of paper-thin strip, in particular to a kind of 450MPa grades of hot rolling low yield strength ratio paper-thin strip
And its manufacturing method.
Background technique
Paper-thin strip is generally referred to as thickness in 2.0mm thin gauge strip below, in practical applications not only to its thickness
Degree proposes thinner requirement, and paper-thin strip is needed to have preferable toughness, lower yield tensile ratio.
The thin gauge low yield strength ratio strip of traditional 450MPa grade utilizes long process hot rolling line, and passes through cold rolling, moves back
Fire process production, cold-strip steel is most thin to can reach 1.0mm.But cold-rolling process and product have production procedure length, low efficiency, cost
High feature.And the production of 2.5mm or less thin slab product is difficult to realize only with conventional hot rolling line and hot rolling technology,
Therefore the thickness of 450~500MPa low yield strength ratio dual phase steel hot-rolled product in the prior art is substantially in 3.0mm or more.
And sheet billet continuous casting and rolling production line is because have the advantages that short route, high efficiency, low energy consumption, and can realize and criticize
The production of thin slab product is measured, product cost is low, and therefore, sheet billet continuous casting and rolling production line can economically produce thin rule
Lattice low yield strength ratio belt steel product realizes " with the hot Dai Leng " of portioned product, but the belt steel product of thin slab continuous casting and rolling production by
It is thinner in the belt steel product of the more conventional hot rolling line production of its crystal grain, therefore the intensity in the wrong of product is higher, leads to yield tensile ratio
It is higher, particularly with the strip of the lower intensity rank of 450MPa, in rolling 2.0mm thin slab product below, production
Difficulty is bigger, is also difficult to realize the production of the low yield strength ratio thin gauge strip below of yield tensile ratio 0.6 at present.
Summary of the invention
The object of the present invention is to provide a kind of 450MPa grades of hot rolling low yield strength ratio paper-thin strips, it not only can be in 450MPa
Grade realizes very thin thickness, and yield tensile ratio is low.
To achieve the above object, the present invention provides a kind of 450MPa grades of hot rolling low yield strength ratio paper-thin strip, it is characterised in that:
Its chemical component is by mass percentage are as follows: C:0.01~0.05%, Si≤0.05%, Mn:0.8%~1.5%, Cr:
0.05%~0.6%, Als:0.015%~0.10%, P≤0.010%, S≤0.006%, N≤0.006%, Ti≤
0.010%, surplus is Fe and inevitable impurity.
Preferably, the metallographic structure of the paper-thin strip is ferritic structure+martensitic structure, wherein ferritic structure
Volume fraction >=90%.
The effect and mechanism of each element and main technique in the present invention:
C: carbon plays solution strengthening in steel, improves the intensity of steel, and carbon also functions to the effect of stable austenite.But carbon content
Its excessively high solution strengthening effect is obvious, and is easy to form pearlite in steel, increases the yield strength of steel, causes steel to be bent strong
Than excessively high, processability is caused to decline, therefore the C content in steel is selected as 0.01%~0.05%.
Mn:Mn plays solution strengthening and stable austenite in steel, it is ensured that forms a certain amount of austenite.Mn contains
Measure too low, the effect of stable austenite is unobvious.Mn too high levels are easy to cause martensite content in steel to increase, and increase in steel
Banded structure declines the toughness of steel, therefore Mn content of the present invention is 0.80~1.50%.
Si:Si solution strengthening effect in steel is significant, and Si too high levels cause the yield strength of steel excessively high, to bend
Strong ratio increases, but pursuing too low Si content causes production cost to rise, therefore Si content of the present invention is≤0.05%.
Cr: playing the role of solution strengthening in steel and improves steel hardenability, but Cr too high levels, leads to yield strength
Increase significantly, therefore Cr content 0.05~0.60% of the present invention.
Al:Al plays the role of deoxidation in steel, and inclusion content of steel is effectively reduced, in addition, Al is dissolved in ferrite, rises
It to the effect of solution strengthening, is affected to yield strength, is easy to form AlN with the N in steel, plays the work of refinement crystal grain
With, therefore Al content 0.015%~0.10% in the present invention.
P:P solution strengthening effect in steel is significant, therefore should reduce its content, P≤0.010% of the present invention as far as possible.
S:S is the impurity element in steel, easily generates segregation in crystal boundary, and form the FeS of low melting point with the Fe in steel, reduces
The toughness of steel should control within 0.006%.
N:N is the impurity element in steel, and solution strengthening effect is significant, and be easy to the Al in steel and Ti etc. and formed AlN and
TiN, and the toughness of steel is reduced, therefore reduce its content as far as possible, it should control within 0.006%.
Ti:Ti is dissolved in ferrite, plays solution strengthening effect, is formed TiC or TiN in conjunction with C and N in steel, is played
Precipitation strength effect, increases the yield strength of steel, causes yield tensile ratio higher, therefore Ti≤0.010% in the present invention.
It is a further object to provide the manufacturing methods of above-mentioned 450MPa grades of hot rolling low yield strength ratio paper-thin strip, should
Method and step is simple, at low cost, is suitable for industrialized production.
To achieve the above object, the present invention provides a kind of side for manufacturing above-mentioned 450MPa grades of hot rolling low yield strength ratio paper-thin strip
Method, it is successively the following steps are included: converter smelting, LF refining, RH application of vacuum, continuous casting, roughing, intermediate base heating, finish rolling, layer
Stream is cooling, batches, in which: the temperature after the intermediate base heating is 1000~1300 DEG C, more preferably 1100~1250 DEG C.
Preferably, the continuous casting, roughing, the heating of intermediate base, finish rolling first three rack process temperature be 900~1300 DEG C.
Preferably, in the continuous casting process, thickness of strand is 70~150mm.
Preferably, the rough rolling process uses 2~3 rack roughing, roughing outlet temperature >=950 DEG C, and roughing exports steel
With a thickness of 6~15mm.It is furthermore preferred that roughing mouth temperature >=1000 DEG C.
Preferably, in the intermediate base heating process, heating time is 5~300s.
Preferably, the finishing stands use 3~5 rack finish rolling, and finish rolling finishing temperature is 900~960 DEG C, finishing rolling mill
The sum of F4, F5 reduction ratio≤10%.
Preferably, the laminar cooling process uses three-stage section cooling, wherein third section cooling rate >=first segment
Cooling rate >=second segment cooling rate, cooling end temperature >=700 DEG C of first segment, three-stage cooling start temperature >=650 DEG C,
Three-stage cooling terminates temperature≤400 DEG C.
It is furthermore preferred that cooling rate≤20 DEG C/s that the second segment is cooling, cooling rate >=50 DEG C of three-stage cooling/
s。
Preferably, the temperature of the coiling process is 100~350 DEG C.
It is using the reasons why above-mentioned technique:
When traditional sheet billet process production 2.0mm very thin hot-rolled product below, slab thickness before finish rolling >=
50mm, thus need to finish rolling Jing Guo 6~7 racks, but in finishing stands, the temperature of steel band is lower, and finishing temperature generally exists
880 DEG C hereinafter, cause austenite grain excessively to refine, and processing hardening phenomenon is obvious, greatly increase its yield strength, cause steel
The yield tensile ratio of material increases.For these reasons, the present invention avoids the excessive refinement and processing hardening of crystal grain using above-mentioned technology, real
The production of existing low yield strength ratio Ultra-thin product.
Continuous casting, roughing, heating, the finishing stands temperature the high more is conducive to occur completely to recrystallize, and softens steel, but
Temperature Tai Gaoyi keeps excessive grain coarse, unfavorable to the toughness of steel.Therefore temperature range of the invention is 900~1300 DEG C.
Thickness of strand is too thin, and the compression ratio of product is too small, steel nonuniform organization, and is easy to cause banded structure, into
And the plasticity and intensity of steel are reduced, and slab thickness is too thick, then needs using powerful rolling equipment, to increase production
Difficulty is unfavorable for cost-effective production this product.Therefore its slab thickness of the invention is 70~150mm.Roughing passage is very little,
Coarse as-cast structure in slab is difficult to refine, to reduce toughness, but roughing passage is too many, roughing outlet temperature is difficult to control
At 950 DEG C or more, it is unfavorable for steel and adequately recrystallization occurs, to keep the yield strength of steel higher.
6~15mm of workpiece thickness behind roughing outlet, workpiece thickness is too thin, and roughing outlet temperature is difficult to control
950 DEG C or more, excessive grain is caused to refine, and then yield tensile ratio is caused to increase.Workpiece thickness is too thick, roughing compression ratio (continuous casting
Base thickness/roughing exit thickness) too small, readily available non-uniform recrystallized structure and the toughness for reducing steel.
Intermediate base heating temperature is too low and heating time is too short, then intermediate base cannot occur sufficiently to soften and crystal grain is grown up,
Cause excessive grain tiny, yield tensile ratio is caused to increase, and heating temperature is excessively high and heating time is too long, is easy to make austenite grain
It excessively grows up, is unfavorable for toughness raising.Therefore heating temperature is 1000~1300 DEG C.
When being rolled using 3~5 racks, it is ensured that finishing temperature is at 900 DEG C or more, to make austenite grain that can fill
The recrystallization divided, and crystal grain is made to obtain a degree of roughening, to reduce the yield strength and yield tensile ratio of steel, but finish to gauge temperature
Degree cannot be too high, too high that excessive grain is caused to be roughened, to reduce the performances such as its toughness.
Finish rolling the 4th and the 5th rack are last two passage of rolling, and when reduction ratio is larger, the processing hardening of steel band is obvious,
Cause yield tensile ratio to increase, therefore uses small reduction ratio.
Section cooling uses three-stage cooling and low-temperature coiling processes, is mainly conducive to obtain the two-phase steel organization of F+M and keep away
The precipitation for exempting from tiny TiC reaches intensity, yield tensile ratio and corresponding elongation percentage of the invention.
The beneficial effects of the present invention are:
The present invention controls the cooling of section cooling by the way that the process of intermediate base heating is arranged among roughing and finish rolling
Condition produces paper-thin strip using hot rolling technology, and not only thickness is minimum can achieve 0.8mm, and yield tensile ratio 0.5 with
Under.Paper-thin strip manufacturing method of the invention compared with traditional cold-rolling process, have process is short, high production efficiency, manufacture at
This low advantage；And compared with traditional hot rolling technology, paper-thin strip manufacturing method of the invention can obtain the thinner band of specification
Steel, and manufacturing process is shorter, manufacturing cost is lower.Paper-thin strip yield tensile ratio of the invention is minimum to can reach 0.5 hereinafter, tension
450~520MPa of intensity, elongation percentage reach 25% or more, and punch forming performance is good, and manufacturing approach craft is simple, cost
It is low, there is very strong practicability.
Specific embodiment
Below by way of specific embodiment to 450MPa grade hot rolling low yield strength ratio paper-thin strip of the invention and its manufacturing method
It is further described:
Embodiment 1
Using converter, LF refining, RH vacuum metling, control steel product ingredient is 0.04%C, 0.02%Si, 1.06%Mn,
This slab is carried out continuous casting, slab by 0.1%Cr, 0.023%Als, 0.008%P, 0.002%S, 0.003%N, 0.005%Ti
This slab, is carried out three passage roughing, obtains the intermediate base of 12mm, intermediate base temperature by thickness 80mm by 1150 DEG C of slab temperature
1000 DEG C, this intermediate base is heated, 1150 DEG C of temperature after heating, then carries out three passage finish rolling, finish rolling finishing temperature 950
DEG C, product thickness 1.5mm carries out section cooling after finish rolling, 25 DEG C/s of first segment cooling rate cools down 720 DEG C of temperature of end, the
15 DEG C/s of two-step cooling rate, 660 DEG C of three-stage cooling start temperature, 100 DEG C/s of cooling rate, cooling terminates 300 DEG C of temperature,
Then it batches, 260 DEG C of coiling temperature, obtains 450MPa grade hot rolling low yield strength ratio paper-thin strip 1 of the invention.Examine microstructure
And mechanical property, ferrite volume fraction 94%, remaining is martensite, yield strength 235MPa, tensile strength 470MPa, Qu Qiang
Than 0.50, elongation percentage 35%, punching performance is good.
Embodiment 2
Using converter, LF refining, RH vacuum metling, control steel product ingredient is 0.035%C, 0.03%Si, 1.16%Mn,
This slab is carried out continuous casting, casting by 0.4%Cr, 0.030%Als, 0.0078%P, 0.001%S, 0.002%N, 0.004%Ti
This slab, is carried out three passage roughing, obtains the intermediate base of 10mm, intermediate base temperature by base thickness 90mm by 1200 DEG C of slab temperature
960 DEG C, this intermediate base is heated, 1100 DEG C of temperature after heating, then carries out four-pass finish rolling, the pressure of the 4th rack of finish rolling
Rate 5%, carries out section cooling by 930 DEG C of finish rolling finishing temperature, product thickness 1.2mm after finish rolling, and 35 DEG C of first segment cooling rate/
S, cooling to terminate 730 DEG C of temperature, second segment cooling rate 18 DEG C/s, 650 DEG C of three-stage cooling start temperature, cooling rate 80
DEG C/s, and it is cooling to terminate 260 DEG C of temperature, it then batches, 200 DEG C of coiling temperature, it is low in the wrong strong to obtain 450MPa grade hot rolling of the invention
Than paper-thin strip 2.Microstructure and mechanical property are examined, ferrite volume fraction 91%, remaining is martensite, yield strength
275MPa, tensile strength 500MPa, yield tensile ratio 0.55, elongation percentage 28%, punching performance is good.
Embodiment 3
Using converter, LF refining, RH vacuum metling, control steel product ingredient is 0.020%C, 0.01%Si, 0.90%Mn,
This slab is carried out continuous casting, casting by 0.55%Cr, 0.050%Als, 0.009%P, 0.001%S, 0.003%N, 0.003%Ti
This slab, is carried out three passage roughing, obtains the intermediate base of 8mm, intermediate base temperature by base thickness 85mm by 1200 DEG C of slab temperature
1020 DEG C, this intermediate base is subjected to heating 15s, 1200 DEG C of temperature after heating, then carries out five passage finish rolling, the 4th rack of finish rolling
Reduction ratio 2%, the 5th rack reduction ratio 8% of finish rolling, 910 DEG C of finish rolling finishing temperature, product thickness 0.8mm carries out layer after finish rolling
Stream cooling, 55 DEG C/s of first segment cooling rate is cooling to terminate 750 DEG C of temperature, 20 DEG C/s of second segment cooling rate, three-stage cooling
It is 660 DEG C of start temperature, 100 DEG C/s of cooling rate, cooling to terminate 230 DEG C of temperature, it then batches, 180 DEG C of coiling temperature, obtains this
The 450MPa grade hot rolling low yield strength ratio paper-thin strip 3 of invention.Examine microstructure and mechanical property, ferrite volume fraction
95%, remaining is martensite, yield strength 230MPa, tensile strength 490MPa, yield tensile ratio 0.47, elongation percentage 30%, stampability
It can be good.
Embodiment 4
Using converter, LF refining, RH vacuum metling, control steel product ingredient is 0.01%C, 0.05%Si, 1.5%Mn,
This slab is carried out continuous casting, casting by 0.10%Cr, 0.060%Als, 0.009%P, 0.002%S, 0.004%N, 0.005%Ti
This slab, is carried out three passage roughing, obtains the intermediate base of 15mm, intermediate base temperature by base thickness 110mm by 1200 DEG C of slab temperature
1050 DEG C, this intermediate base is subjected to heating 30s, 1200 DEG C of temperature after heating, then carries out four-pass finish rolling, the 4th rack of finish rolling
Reduction ratio 0%, the 5th rack reduction ratio 6% of finish rolling, 960 DEG C of finish rolling finishing temperature, product thickness 1.8mm carries out layer after finish rolling
Stream cooling, 25 DEG C/s of first segment cooling rate is cooling to terminate 760 DEG C of temperature, 10 DEG C/s of second segment cooling rate, three-stage cooling
It is 680 DEG C of start temperature, 60 DEG C/s of cooling rate, cooling to terminate 300 DEG C of temperature, it then batches, 260 DEG C of coiling temperature, obtains this
The 450MPa grade hot rolling low yield strength ratio paper-thin strip 4 of invention.Examine microstructure and mechanical property, ferrite volume fraction
96%, remaining is martensite, yield strength 240MPa, tensile strength 510MPa, yield tensile ratio 0.47, elongation percentage 26%, stampability
It can be good.
The scientific research personnel of technical field can according to the above-mentioned change for making content and form unsubstantiality without departing from
Institute's essential scope of the present invention, therefore, the present invention is not limited to above-mentioned specific embodiment.
Claims (10)
1. a kind of 450MPa grades of hot rolling low yield strength ratio paper-thin strip, it is characterised in that: its chemical component is by mass percentage
Are as follows: C:0.01~0.05%, Si≤0.05%, Mn:0.8%~1.5%, Cr:0.05%~0.6%, Als:0.015%~
0.10%, P≤0.010%, S≤0.006%, N≤0.006%, Ti≤0.010%, surplus are Fe and inevitable impurity；
The 450MPa grades of hot rolling low yield strength ratio paper-thin strip manufactures by the following method to be obtained, it successively includes following step
Rapid: converter smelting, RH application of vacuum, continuous casting, roughing, intermediate base heating, finish rolling, section cooling, batches at LF refining, in which: institute
Temperature after stating intermediate base heating is 1000~1300 DEG C.
2. 450MPa grades of hot rolling low yield strength ratio paper-thin strip according to claim 1, it is characterised in that: the paper-thin strip
Metallographic structure be ferritic structure+martensitic structure, wherein volume fraction >=90% of ferritic structure.
3. the method for 450MPa grades of hot rolling low yield strength ratio paper-thin strips described in a kind of any one of manufacturing claims 1 or 2, special
Sign is: it is successively the following steps are included: converter smelting, LF refining, RH application of vacuum, continuous casting, roughing, intermediate base heating, essence
It rolls, section cooling, batch, in which: the temperature after the intermediate base heating is 1000~1300 DEG C.
4. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: described
In continuous casting process, thickness of strand is 70~150mm.
5. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: described
Rough rolling process uses 2~3 rack roughing, roughing outlet temperature >=950 DEG C, and it is 6~15mm that roughing, which exports thickness of steel product,.
6. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: described
In intermediate base heating process, in the intermediate base heating process, heating time is 5~300s.
7. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: described
Finishing stands use 3~5 rack finish rolling, and finish rolling finishing temperature is 900~960 DEG C, and the sum of finishing rolling mill F4, F5 reduction ratio≤
10%.
8. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: described
Laminar cooling process uses three-stage section cooling, and wherein third section cooling rate >=first segment cooling rate >=second segment is cooling
Rate, first segment is cooling to terminate temperature >=700 DEG C, three-stage cooling start temperature >=650 DEG C, three-stage cooling terminate temperature≤
400℃。
9. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 8, it is characterised in that: described
Second segment cooling cooling rate≤20 DEG C/s, cooling rate >=50 DEG C/s of three-stage cooling.
10. the manufacturing method of 450MPa grades of hot rolling low yield strength ratio paper-thin strips according to claim 3, it is characterised in that: institute
The temperature for stating coiling process is 100~350 DEG C.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101279330A (en) * | 2008-01-25 | 2008-10-08 | 北京科技大学 | Method for producing hot rolling two-phase steel plate at 700MPa level of tensile strength |
| CN101717886A (en) * | 2009-11-20 | 2010-06-02 | 江苏省沙钢钢铁研究院有限公司 | Hot-rolled dual-phase steel plate with 650 MPa-level tensile strength and manufacturing method thereof |
| CN102703815A (en) * | 2012-06-19 | 2012-10-03 | 东北大学 | 600 MPa-grade hot-rolled dual-phase steel and preparation method thereof |
| CN102912235A (en) * | 2012-10-29 | 2013-02-06 | 武汉钢铁(集团)公司 | Hot-rolled dual-phase steel in 590MPa tensile strength grade and method for manufacturing hot-rolled dual-phase steel |
| CN103305762A (en) * | 2013-06-21 | 2013-09-18 | 安徽工业大学 | Cold-rolled dual-phase sheet steel with 400MPa-level tensile strength and preparation method thereof |
| CN104357744A (en) * | 2014-11-17 | 2015-02-18 | 武汉钢铁(集团)公司 | Tensile strength more than or equal to 780MPa grade hot-rolled dual phase steel and production method thereof |
| CN105316579A (en) * | 2014-07-29 | 2016-02-10 | 上海梅山钢铁股份有限公司 | Thin hot rolled pickled steel plate and fabrication method thereof for water heater enamel liner |
-
2017
- 2017-07-13 CN CN201710571164.3A patent/CN107338395B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101279330A (en) * | 2008-01-25 | 2008-10-08 | 北京科技大学 | Method for producing hot rolling two-phase steel plate at 700MPa level of tensile strength |
| CN101717886A (en) * | 2009-11-20 | 2010-06-02 | 江苏省沙钢钢铁研究院有限公司 | Hot-rolled dual-phase steel plate with 650 MPa-level tensile strength and manufacturing method thereof |
| CN102703815A (en) * | 2012-06-19 | 2012-10-03 | 东北大学 | 600 MPa-grade hot-rolled dual-phase steel and preparation method thereof |
| CN102912235A (en) * | 2012-10-29 | 2013-02-06 | 武汉钢铁(集团)公司 | Hot-rolled dual-phase steel in 590MPa tensile strength grade and method for manufacturing hot-rolled dual-phase steel |
| CN103305762A (en) * | 2013-06-21 | 2013-09-18 | 安徽工业大学 | Cold-rolled dual-phase sheet steel with 400MPa-level tensile strength and preparation method thereof |
| CN105316579A (en) * | 2014-07-29 | 2016-02-10 | 上海梅山钢铁股份有限公司 | Thin hot rolled pickled steel plate and fabrication method thereof for water heater enamel liner |
| CN104357744A (en) * | 2014-11-17 | 2015-02-18 | 武汉钢铁(集团)公司 | Tensile strength more than or equal to 780MPa grade hot-rolled dual phase steel and production method thereof |
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