CN103757533B - The high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa and manufacture method thereof - Google Patents
The high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa and manufacture method thereof Download PDFInfo
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Abstract
The high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa and manufacture method thereof, it comprises the steps: 1) use double roller continuous casting cast thickness to be the Cast Strip of 1.0 5.0mm, its chemical component weight percentage is: C 0.25 0.40%, Si 0.15 0.40%, Mn 1.3 2.0%, P≤0.015%, S≤0.01%, N≤0.012%, remaining is Fe and inevitable impurity；2) Cast Strip cooling；3) the online hot rolling in Cast Strip；4) hot-rolled strip cooling；5) batch；6) cold rolling；7) blue annealing.The high-strength tie that the present invention is produced by the economy technique carrying out recovery annealing after thin strap continuous casting+cold rolling, tensile strength >=1000MPa, elongation percentage >=12%.
Description
Technical field
The present invention relates to high strength steel tie and manufacture method thereof, particularly relate to a kind of tensile strength
The thin strap continuous casting economy high strength steel tie of >=1000MPa and manufacture method thereof.
Background technology
Steel tie is a kind of thin ribbon shaped deep processed product of steel, be mainly used to tie up steel, non-ferrous metal,
Light textile goods, building materials, paper roll (plate) and wool and other items.In order to ensure safe handling of cargo and fortune
Defeated, it is desirable to tie has higher tensile strength and certain elongation percentage.Further, since tie is long-term
Use in outdoor environment, it is also desirable to have certain corrosion resistance.
Steel tie divides according to intensity, can be divided into low strong, in strong, high-strength and strong four classes of superelevation.Wherein
High-strength tie, be mainly used in tying up in iron and steel enterprise coils of hot-rolled steel, round steel, shaped steel, steel pipe,
The product such as wire rod and pipe line steel, it is in great demand.
With developing rapidly of metallurgy industry, high-quality, the steel products output of high intensity grade are got over
Coming bigger, the coil diameter of coil of strip is also increasing, and monovolume reaches 30 tons, even 40 tons, strong for tie
The requirement of degree improves constantly, and consumption also increases continuous.Therefore, the height that low cost process produces is used
Strength steel tie has boundless market prospects.
But, owing to high strength steel tie requires have higher intensity and elongation percentage simultaneously, therefore give birth to
Produce difficulty bigger.At present, the production technology of high strength steel tie mainly has three kinds:
First, the technique carrying out recovery annealing process after cold rolling.
This technique generally includes following steps: 1) utilize tradition continuous casting+slab reheating+hot continuous rolling
Technique produces hot-rolled strip；2) by cold rolling thickness hot-rolled strip being thinned to required for high-strength tie；3)
Blue annealing process is carried out to cold rolling strap.
Hot rolled strip intensity after cold rolling is largely increased, but elongation percentage falls too low.By replying
After annealing, steel band intensity decreases, but elongation percentage is improved, so that steel band reaches one
Fixed strong plasticity coupling, forms blue layer oxide-film in steel strip surface simultaneously, plays oxidation resistant work
With.The final microscopic structure of steel band is usually cold working recovery annealing ferrite matrix and spreads all over matrix more
Dissipate carbide.This technological operation is simple, with low cost, energy resource consumption is few, environmental pollution is little.
Owing to first tensile strength and the elongation percentage of tie are to be affected by hot rolling material performance, then pass through
Cold rolling power rate and annealing treating process are regulated.Do not produce special in the market for high-strength tie
The hot rolling raw material of design, high-strength tie produces and generally selects the alloy being mainly composed of C, Si, Mn
Structural steel.The organization type of this kind of hot-rolled product of the market supply of material and various composition phase content fluctuate relatively
Greatly, determining that its tensile property changes greatly, so it will ripple to the influence degree of high-strength tie performance
Dynamic bigger.In addition, the thickness specification of this kind of hot-rolled product of the market supply of material compares limitation, if different
The high-strength tie of thickness uses the hot rolled plate of similar thickness to produce, then the change of cold rolling reduction ratio
Scope is just relatively big, and the Hot Rolling Plate Production thickness for example with 2.8mm is respectively 1.0mm and 0.5mm
High-strength tie, cold rolling reduction ratio is respectively 64% and 82%, its performance impact journey to high-strength tie
Degree will fluctuate bigger.Two above fluctuation determines for different hot rolling raw materials, it is necessary to use not
Same annealing process carries out the last adjustment of tie performance, and otherwise tie performance can be very different.?
During annealing process adjusts, tie performance is very sensitive to parameter and annealing, when tie tension is strong
When spending higher, elongation percentage is generally relatively low；And when the elongation percentage of tie is higher, tensile strength is generally relatively
Low, tie to be made has higher intensity and elongation percentage simultaneously, relatively difficult.Above-mentioned reason causes,
Utilize cold rolling after carry out recovery annealing process technique produce steel tie, its tensile strength and elongation percentage are very
Difficult breakthrough 980MPa and 12%.This technique seems simple, must with production tensile strength and extension
Rate has the high-strength tie of more preferably coupling, and difficulty is bigger.
Chinese patent 02109635.X discloses " a kind of high-intensity packing steel belt and Technology for Heating Processing ",
Composition is used to be C0.22-0.29%, Si0.015%, Mn1.30-1.50%, P≤0.015%, S≤
0.010%, Als0.015%, Nb0.012%, the hot rolled plate raw material of balance of Fe, cold rolling after carry out
Electrical heating blue annealing process, annealing furnace temperature is 550-650 DEG C, and steel belt operating speed is
Its speed of 2.5-3.5m/min(is directly proportional to furnace temperature and body of heater length).Utilize the steel that this patent produces
Tie tensile strength reaches 920MPa, and elongation percentage reaches 11%.
Chinese patent 200410031162.8 disclosed " high-intensity packing steel belt and manufacturing process thereof ", adopts
It is C0.25-0.28% with composition, Si0.02-0.06%, Mn1.30-1.50%, P0.01-0.02%, S
0.001-0.012%, Als0.03-0.06%, the hot rolled plate raw material of balance of Fe, hot rolled plate thickness is
1.8-3.75mm, through 68-83% cold rolling after, obtaining thickness is 0.3-1.2mm steel band, utilizes continous way
Heating furnace makes annealing treatment, and steel band heating-up temperature is 450-550 DEG C.Utilize the steel that this patent produces
Tie tensile strength >=930MPa, elongation percentage >=8%.
Chinese patent 201210232927.9 disclosed " production method of high intensity blue steel strip ", uses
C0.19-0.21%, Mn1.62-1.71%, Si0.02-0.028%, P0.014-0.018%, S
0.0042-0.006%, Als0.033-0.05%, the composition design of balance of Fe, through smelting, even
The processing steps such as casting, hot rolling, cold rolling, blue annealing carry out steel tie production.Cold rolling reduction ratio is 70%,
Blue annealing temperature is 580-700 DEG C, and the time of turning blue is 100-160s.Utilize the steel that this patent produces
Tie tensile strength is 950-960MPa, and elongation percentage is 11.5-12%.
2nd, the technique of cold rolling laggard quadrat bath means of isothermal quenching
This technique generally includes following steps: 1) utilize tradition continuous casting+slab reheating+hot continuous rolling
Technique produces hot-rolled strip；2) by cold rolling thickness hot-rolled strip being thinned to required for high-strength tie；3)
Carry out heating austenitizing to the steel band after cold rolling；4) lead patenting.
Pass through lead patenting, it is thus achieved that bainite structure, thus obtain steel band intensity to be wanted and
Plasticity.The greatest problem utilizing this technique to produce is to produce device structure complexity, expensive, equipment
Cost is high；Lead bath cooling capacity is limited, needs time enough to complete austenite to bainite transformation,
Production efficiency is low；Serious environmental pollution can be caused；Production cost is high.Some countries have started to limit
Use.And, although the steel tie intensity utilizing this technique to produce is higher, but elongation percentage is relatively low,
It is susceptible to brittle failure during use.
United States Patent (USP) US6814817 is disclosed " Steel Strap Composition ", is C by composition
The cold-rolled strip of 0.30-0.36%, Mn0.90-1.25%, Si0.75-1.10%, is initially pre-heated to 370-510
DEG C, it is then heated to 815-900 DEG C and carries out Ovshinsky, then carry out at 370-510 DEG C of lead patenting
Reason.Utilize steel tie tensile strength >=1170MPa that this technique produces, elongation percentage >=6.5%.
Chinese patent 200810200449.7 disclosed " heat treatment method of a kind of steel belt for packages ", adopts
It is C0.29-0.35% with composition, Si0.15-0.35%, Mn1.20-1.55%, P0.030%, S
0.030%, the hot rolled plate of balance of Fe, cold rolling after first in lead bath, be preheating to 355-365 DEG C, in advance
Heat time 6.75-9s, is then heated to 860 ± 20 DEG C, and insulation 30-40s carries out austenitizing, then enters
355-365 DEG C of lead patenting process of row, isothermal quenching time is 21-28s.Utilize this technique raw
The steel tie tensile strength >=1350MPa producing, elongation percentage >=6%.
3rd, the technique carrying out two-phase section Quenching Treatment after cold rolling
This technique generally includes following steps: 1) utilize tradition continuous casting+slab reheating+hot continuous rolling
Technique produces hot-rolled strip；2) by cold rolling thickness hot-rolled strip being thinned to required for high-strength tie；3)
Steel band after cold rolling is heated to ferrite and austenite two-phase section；4) rapid quenching.
Quenched by two-phase section, it is thus achieved that microscopic structure be martensite+cold working recovery annealing ferrite
Matrix and the diffusion carbide spreading all over matrix, thus obtain steel band intensity to be wanted and plasticity.Utilize
The steel tie that this technique produces, intensity and elongation percentage are all higher.But this technique Structure of need complexity
Electromagnetic induction rapid-heating device and strength water cooling equipment, equipment cost is high；Production process is more complicated,
Production cost is higher；And thin plate is often not ideal enough in two-phase section quenching back plate shape.
United States Patent (USP) US6635127 is disclosed " Steel strapping and method of making ",
Composition is used to be C≤0.2%, Mn≤2.0%, Si0.2-0.4%, Ti0.025-0.045%, V
0.05-0.07%, Cr≤0.25%, Ni≤0.30%, Mo≤0.10%, Cu≤0.20%, Al≤0.08%,
Nb≤0.005%, N≤0.005%, P≤0.035%, S≤0.02%, the steel billet of balance of Fe is through warm
Roll, cold rolling after, quick sensing is heated to 750 DEG C, is incubated 2s, is then rapidly quenched to room temperature.Utilizing should
The steel tie tensile strength that technique produces is 970-1070MPa, and elongation percentage is 10-14%.
Chinese patent 200910046229.8 " the high-strength binding band steel higher than 1100MPa for the tensile strength and
Its manufacture method ", employing C0.25-0.35%, Mn1.24-2.0%, Si≤0.45%, S≤0.04%,
The composition design of P≤0.04%, through smelting, continuous casting, hot rolling, cold rolling, ferrite+austenite two
The processing steps such as phase region quenching, tempering carry out steel tie production.Hardening heat is 730-790 DEG C, quenches
Spending >=100 DEG C/s at top speed, temperature is 430-530 DEG C.Utilize the steel tie tension that this technique produces
Intensity >=1100MPa, elongation percentage >=10%.
In above-mentioned patent, produce the hot-rolled strip raw material that high-strength tie is used, be all to utilize tradition even
Casting+hot rolling technology flow process produces.Due to the specification of hot-rolled strip raw material own, tissue, the limit of aspect of performance
System, and the restriction of the operation such as follow-up cold rolling, heat treatment itself so that utilize above-mentioned technique to produce
High-strength tie production cost or performance are difficult to obtain and break through.
At present, some emerging technologies, such as CSP, thin strap continuous casting etc., it is also possible to use
Produce hot-rolled strip.Wherein, strip continuous casting technology is metallurgical and a forward position in investigation of materials field
Technology, its steel and iron industry that appears as brings a revolution, and it changes tradition and controls hot rolling in metal working industry
Casting, rolling, even heat treatment etc. continuously are integrated, make production by the production process of steel band
Strip base form thin steel strip through the online hot rolling of a time is just disposable, enormously simplify production work
Sequence, shortens the production cycle.Equipment investment also reduces accordingly, and product cost significantly reduces.
It about the patent of thin strap continuous casting product and manufacturing process thereof, is concentrated mainly on mild steel and low-carbon (LC) is micro-
Alloy steel product and manufacturing process thereof, the aspect such as product surface quality improvement, such as Chinese patent
201080008606.X " hot rolled thin cast steel strip product and manufacture method thereof ", Chinese patent
201080017436.1 " high strength thin cast strip product and preparation method thereof ", Chinese patent
200880109715.3 " thin strip slab that micro-crack is reduced " etc..
The steel band being manufactured by above-mentioned thin strap continuous casting patent, is not to design for high-strength tie produces,
Have not yet to see and the steel band that thin band continuous casting technique produces is used for the precedent that high-strength tie produces.Actual
On, the final performance of high-strength tie is by the specification of hot rolling carrying raw material, and hot-rolled strip tissue and performance shadow
Ring relatively big, during in particular by the first technique of relatively inexpensive high-strength tie production.Therefore,
Want that the steel band using thin band continuous casting technique to produce, as raw material, produces to economy the height of excellent performance
Strong tie, carries out specialized designs and manufacture to thin strap continuous casting steel band, most important.
Content of the invention
The thin strap continuous casting economy that it is an object of the invention to provide a kind of tensile strength >=1000MPa is high
Strong tie and manufacture method thereof, by the design of rational composition design and processes, solve prior art
The problem that environmental pollution is serious, production efficiency is relatively low, production cost is high existing, and utilize existing
The strong plasticity of high-strength tie that economy technology produces mates undesirable problem.
The technology design of the present invention is as follows:
The present invention use cold rolling after carry out the processing technology routine of recovery annealing process to produce high-strength bundle
Band.Taking this process route to produce high-strength tie, its performance design mainly considers three aspects: one is
By the proper property of the produced Cast Strip of thin band continuous casting technique, mainly determined by composition and tissue morphology；
Two is cold rolling working hardening, is mainly determined by cold rolling reduction ratio；Three be recovery annealing soften, mainly by
Annealing process after cold rolling determines.Closely, each side is required in contact between these three aspect
Stability contorting, and the stability contorting of a rear step must obtain the basis of stability contorting at back
Upper just can be achieved, thus realize the ideal coupling of the strong plasticity of high-strength tie, it is achieved the present invention is imitated
Really.
The present invention passes through chemical composition and thin band continuous casting technique design, the microscopic structure type to hot-rolled strip
Carry out fixing quantity, and then the mechanical property of stability contorting hot-rolled strip with composition phase content, and to height
The impact of strong tie mechanical property.Designed by thin band continuous casting technique, the thickness specification of hot-rolled strip is entered
Row accurately control, and then the cold rolling reduction ratio that the production of stability contorting different-thickness high-strength tie is used,
And the impact on high-strength tie mechanical property.And design is suitable for thin strap continuous casting hot-rolled strip microscopic structure
The blue annealing technological parameter of type and cold rolling reduction ratio.Replied by after thin strap continuous casting+cold rolling
The economic production technique of annealing, it is achieved the more excellent coupling of high-strength tie tensile strength and elongation percentage.
The high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa, its chemical component weight hundred
Proportion by subtraction is: C0.25-0.40%, Si0.15-0.40%, Mn1.3-2.0%, P≤0.015%, S≤0.01%,
N≤0.012%, remaining is Fe and inevitable impurity；
In the Design of Chemical Composition of the present invention:
C:C is intensified element most economical, most basic in steel, by solution strengthening and precipitation strength
Improve the intensity of steel.C can be dissolved in ferrite formation interstitial solid solution, but at room temperature it is at iron
Solubility in ferritic is extremely limited, and therefore its solution strengthening effect is restricted.At present invention process
Under the conditions of, C mainly separates out with cementite form, as the part of pearlite.Containing of pearlite
Measuring closely related with C content, when C content increases, content of pearlite in alloy increases, the intensity of steel, hard
Degree improves therewith, and plasticity, toughness reduce accordingly.Therefore C content can not be too high, and the present invention uses
C content scope be 0.25-0.40%.
Preferably, C content scope is 0.28-0.38%, and steel band can obtain more suitably content of pearlite in alloy,
Can have more excellent tensile strength and elongation percentage coupling.
Si:Si plays solution strengthening effect in steel.When Si content is suitable, the intensity of steel is not only made to obtain
Improve, and little on plasticity impact.The Si content range that the present invention uses is 0.15-0.4%.
Preferably, Si content range is 0.25-0.35%, and steel band can have more excellent tensile strength and prolong
Stretch rate coupling.
Mn:Mn is one of generally the least expensive alloying element of price, and it has sizable solid solution in steel
Degree, is improved the intensity of steel by solution strengthening, and when its content is suitable, to the plasticity of steel substantially without
Infringement, is the topmost intensified element of intensity improving steel in the case of reducing C content.The present invention adopts
Mn content range be 1.3-2.0%.
Preferably, Mn content range is 1.5-1.8%, and steel band can have more excellent tensile strength and prolong
Stretch rate coupling.
P:P solubility in α-Fe is very big.Compared with other elements, P is caused in α-Fe
Solid solution strengthening effect is bigger.But when P content is higher, as the intensity of steel improves, its plasticity is obvious
Reduce.In the case of particularly segregation occurs in P in steel, bigger cold brittleness will be caused.In the present invention,
P is to control as impurity element, its content≤0.015%.
Solubility in Fe for the S:S is minimum, and the mostly chemical combination of the S in steel is FeS, its harm be
The red brittleness of steel can be caused when carrying out hot-working, reduce ductility and the toughness of steel, cause when rolling
Crackle.In the present invention, S is to control as impurity element, its content≤0.01%.
N: similar with C element, N element can be improved the intensity of steel by gap solid solution, but, N
Plasticity and toughness to steel for the gap solid solution have bigger harm, therefore N content can not be too high.The present invention
N content≤0.012% using.
The thin strap continuous casting economy high-strength tie manufacture method of the tensile strength >=1000MPa of the present invention,
Comprise the steps:
1) Cast Strip using twin-roll thin strip continuous casting cast thickness to be 1.0-5.0mm, its chemistry becomes
Point percentage by weight is: C0.25-0.40%, Si0.15-0.40%, Mn1.3-2.0%, P
≤ 0.015%, S≤0.01%, N≤0.012%, remaining is Fe and inevitable impurity；
2) cooling down Cast Strip, cooldown rate is 20-80 DEG C/s；
3) online hot rolling, finishing temperature >=900 DEG C, hot rolling reduction ratio≤10%, hot rolling are carried out to Cast Strip
The thickness of rear steel band is 0.9-5.0mm；
4) cooling down hot-rolled strip, cooldown rate is 10-50 DEG C/s；
5) batching hot-rolled strip, coiling temperature is 630-730 DEG C；Hot-rolled strip microscopic structure by
More than 80% pearlite, and a small amount of polygonal ferrite and acicular ferrite composition, and
In pearlite, cemetite lamellae layer thickness is nanometer scale, cemetite lamellae interlamellar spacing be nanometer or
Sub-micrometer scale；
6) carrying out cold rolling to hot-rolled strip, cold rolling reduction ratio is 65-75%, and cold rolling rear thickness of strips is
0.3-1.2mm；
7) carrying out blue annealing to cold rolling strap, annealing temperature is 500-550 DEG C, and annealing time is
120-180s.Microscopic structure after cold rolling strap annealing, is the ferrite matrix of recovery annealing
Upper Dispersed precipitate cementite particle or the cementite stub of a diameter of nanometer scale；High
Tensile strength >=the 1000MPa of strong tie, elongation percentage >=12%.
Further, in described step 1), the content range of C is 0.28-0.38%, with percentage by weight
Meter.
In described step 1), the content range of Mn is 1.5-1.8%, by weight percentage.
In described step 1), the content range of Si is 0.25-0.35%, by weight percentage.
Also, described step 2) in, Cast Strip cooldown rate is 30-60 DEG C/s.
In described step 3), hot rolling reduction ratio is 5-10%.
In described step 4), hot-rolled strip cooldown rate is 10-40 DEG C/s.
In described step 5), the tensile strength of hot-rolled strip is 630-680MPa, elongation percentage >=15%.
In addition, in described manufacture method, step 8) can also be increased as required and steel band is applied
Paint or the subsequent treatment such as zinc-plated.
In the manufacturing process of the present invention:
1) thin strap continuous casting
Molten steel is introduced in a pair and rotates against and that the crystallization roll of internal water cooling and side seal board are formed is molten
Within pond, direct pouring after rapid solidification goes out the Cast Strip that thickness is 1.0-5.0mm.This finger gauge
Lattice pass through high-strength tie finished product thickness, and the online hot rolling reduction ratio of subsequent design and cold rolling strengthening institute
Reduction ratio inverse is needed to obtain.
2) Cast Strip cooling
Cast Strip from crystallization roll continuous casting out after, through confined chamber, cool down in confined chamber.In order to
Inside, control Cast Strip and surface quality, prevent austenite crystal from high temperature growing up too fast simultaneously, control
The cooldown rate of Cast Strip is 20-80 DEG C/s.Preferably, the cooldown rate of Cast Strip is 30-60 DEG C/s.Casting
Band cooling uses air cooling mode, and pressure, the gentle nozzle location of flow of cooling gas can be regulated and control
System.Cooling gas can be the inert gases such as argon gas, nitrogen, helium, or several gas is mixed
And gas.By between the type of control cooling gas, pressure, flow, and nozzle to Cast Strip
Distance etc., it is achieved the control to Cast Strip cooldown rate.
3) the online hot rolling in Cast Strip, cool down and batch
The performance to high-strength tie for the tensile property of hot-rolled strip has a significant impact.Produce same intensity rank
High-strength tie, the performance of hot-rolled strip used should not change too big, otherwise cannot realize to high-strength bundle
Stability contorting with performance.The performance of hot-rolled strip is determined by composition and organization type.Hot-rolled strip to be controlled
Stable performance, its organization type and composition phase content should be stablized as far as possible.Because organization type is cold to steel band
The ability resisting recrystallization after rolling also has considerable influence, and therefore tissue stabilization is also beneficial to cold rolled annealed work
Skill designs.
The control of organization type and tissue phase content is mainly realized by hot rolling reeling process.
The present invention controls temperature >=900 DEG C processed eventually, makes hot rolling carry out in austenitic area.
The present invention controls hot rolling reduction ratio≤10%, it is preferred that hot rolling reduction ratio is 5-10%.After hot rolling
The thickness range of steel band is 0.9-5.0mm.In actual production, the thickness of hot-rolled strip passes through to be produced
High-strength tie thickness specification, and the required reduction ratio of cold rolling processing carries out inverse.For example, thickness is produced
The high-strength tie that degree is 0.5mm, required cold rolling reduction ratio is 65%, then the thickness of hot-rolled strip should
For 1.43mm.Can realize that product thickness specification changes flexibly by adjusting thin band continuous casting technique parameter,
This is a big advantage of strip continuous casting technology.
Controlling hot rolling reduction ratio in such scope, reason has three: first, by a small amount of hot rolling
Inside, Cast Strip and surface quality can be improved further；Second, in order to make austenite not send out after hot rolling
Raw recrystallization, hot rolling drafts can not be too big.Deformation is the basis that recrystallization occurs, and is recrystallization
Driving force deformation stores the source of energy, just can occur after must be over certain driving force
Recrystallization, therefore recrystallization just can occur after only having more than certain deformation quantity.Deformation quantity is bigger, shape
Becoming storage can be bigger, and deformation storage can be bigger, and Recrystallization nucleation and growth rate are all bigger, even if
Also can sufficiently rapidly start at a lower temperature and complete recrystallization.Once austenite is sent out after hot rolling
Raw recrystallization, austenite structure stability is difficult to control, in turn result in by the follow-up cooling of control and
The content of pearlite in alloy generation larger fluctuation that coiling technique parameter is obtained, thus affect steel band tensile property
Stability contorting.3rd, make that hot-rolled strip thickness will not subtract is too thin.Because producing high-strength tie also needs
To ensure certain reduction ratio in follow-up cold rolling step, the control thinking of reduction ratio is as detailed below.
The modes such as aerosol cooling, section cooling or spraying cooling are used to cool down hot-rolled strip.Cold
But the flow of water, flow velocity, and delivery port position etc. can be regulated, thus realize cooling down hot-rolled strip
The control of speed.The cooldown rate that the present invention controls hot-rolled strip is 10-50 DEG C/s, it is preferred that hot-rolled strip
Cooldown rate be 10-40 DEG C/s.The speed of cooldown rate determines last coiling temperature.Technical process
In, different cooldown rates need to be taked according to the difference of thin strap continuous casting steel band pulling rate and tape thickness, will
Oiler temperature control is in desired scope.
The coiling temperature that the present invention controls hot-rolled strip is 630-730 DEG C, in the range of this coiling temperature,
The microscopic structure of hot-rolled strip can be controlled by more than 80% pearlite, and a small amount of polygonal ferrite and
Acicular ferrite is constituted.And cemetite lamellae layer thickness is nanometer scale in pearlite, cemetite lamellae interlayer
Away from for nanometer or sub-micrometer scale.Having the hot-rolled strip of this microscopic structure, its tensile strength is
630-680MPa, elongation percentage >=15%.
4) hot-rolled strip is carried out cold rolling
The cold rolling reduction ratio of hot-rolled strip is very big to the performance impact of high-strength tie, is to improve tie performance
Important parameter, the performance of tie can increase with the increase of cold rolling reduction ratio.Produce same intensity level
Other high-strength tie, cold rolling reduction ratio should not change too big, otherwise cannot realize to high-strength tie
The stability contorting of energy.And the change of cold rolling reduction ratio is too greatly to the ability resisting recrystallization after cold rolling band steel
Also having considerable influence, thus having influence on the selection of parameter and annealing, this also can affect to high-strength tie
The stability contorting of performance.In addition, the design of cold rolling reduction ratio total amount, high-strength tie performance should be met and set
Meter requires, guarantees that material does not ftractures in cold-rolled process again, can not be formed at material internal
Micro-crack.The hot-rolled strip that the present invention obtains, in microscopic structure, more than 80% is pearlite, cemetite lamellae
Layer thickness is nanometer scale, can elongate, the deformation of the form such as bending in cold-rolled process, no
Easily occur broken, thus will not cause defect at material internal.Based on above-mentioned consideration, control of the present invention
It is 65-75% that refrigeration rolls reduction ratio, changes in the range of 10%.
5) cold rolling strap blue annealing
The selection of parameter and annealing is most important.In annealing process, matrix is replied, and causes steel
Band strength reduces, and elongation percentage improves.Temperature can not too high or time can not be long, otherwise can cause steel
Band strength declines too many, and temperature can not be too low or the time is too short, and elongation percentage otherwise can be caused to go up not
Enough.Also to simultaneously take account of, the height of annealing temperature with under hot-rolled strip microscopic structure type and cold rolling
Rate relation is very big.The hot-rolled strip that the present invention obtains, in microscopic structure, more than 80% is pearlite, carburizing
Body lamellar spacing is nanometer scale, and cemetite lamellae interlamellar spacing is nanometer or sub-micrometer scale, makes material exist
Annealing process is relatively strong to Recovery and recrystallization resistivity, therefore can properly increase annealing temperature
And/or annealing time.
In view of above-mentioned, it is 500-550 DEG C that the present invention controls annealing temperature, and annealing time is 120-180s.
Under the conditions of this annealing process, the microscopic structure of steel band is that on the ferrite matrix of recovery annealing, disperse divides
Cementite particle or the cementite stub of a diameter of nanometer scale by cloth.Tie finally obtains and more manages
The tensile strength thought and the coupling of elongation percentage.
6) japanning or the subsequent treatment such as zinc-plated
According to the application target of high-strength tie and use environment etc., the steel band after blue annealing can be entered
Row japanning or the subsequent treatment such as zinc-plated.
The difference of the present invention and prior art and beneficial effect:
1) existing produce high-strength tie cold rolling after carry out the technique of recovery annealing process, not to hot rolling
Composition phase content in raw material microscopic structure and hot rolling raw thickness specification are controlled, and cause steel band
Tensile strength and elongation percentage coupling are undesirable, are difficult to break through 980MPa and 12%.By the present invention's
Thin band continuous casting technique designs, the microscopic structure type of control thin strap continuous casting hot-rolled strip, and fixing quantity shows
Micro-assembly robot mainly comprises the content of phase；According to high-strength tie thickness specification inverse strip to be produced
The thickness of continuous casting hot-rolled strip simultaneously accurately controls, and then the mechanical property of stability contorting hot-rolled strip and cold
Roll the impact on high-strength tie mechanical property for the reduction ratio.Design is suitable for micro-group of thin strap continuous casting hot-rolled strip
Knit the blue annealing technological parameter of type and cold rolling reduction ratio, it is achieved that high-strength tie tensile strength and prolonging
Stretch the more excellent coupling of rate, tensile strength >=1000MPa, elongation percentage >=12%.
2) technique that prior art produces high-strength tie is: tradition continuous casting+slab reheating+heat is even
Roll+cold rolling+recovery annealing or lead patenting or two-phase section quenching.The present invention produces high-strength tie
Technique be: carry out recovery annealing after thin strap continuous casting+online hot rolling+cold rolling, shorten technological process,
Simplify processing step, after the high-strength tie performance being produced is better than utilizing existing tradition continuous casting+cold rolling
Carry out the high-strength tie of recovery annealing technique production, be better than or close to utilizing existing lead patenting
The high-strength tie that technique and two-phase section isothermal quenching technique produce.
3) present invention produces the technology of high-strength tie, flow process is short, technological operation is simple, with low cost,
Energy resource consumption is few, discharge less, environmental pollution little.Solve the environmental pollution that prior art exists serious,
The problem that production efficiency is relatively low, production cost is high, and utilize that existing economy technology produces high-strength
The undesirable problem of tie strong plasticity coupling.
Brief description
Fig. 1 is the microscopic structure of thin strap continuous casting hot-rolled strip in the embodiment of the present invention 1.
Fig. 2 is the cementite of thin strap continuous casting hot-rolled strip microscopic structure medium pearlite in the embodiment of the present invention 1
Lamella.
Fig. 3 is microscopic structure after cold rolling for the thin strap continuous casting hot-rolled strip in the embodiment of the present invention 1
Fig. 4 is the microscopic structure in the embodiment of the present invention 1 after cold rolling strap annealing
Detailed description of the invention
Below in conjunction with embodiment and accompanying drawing, the present invention will be further described.
The molten steel of embodiment of the present invention 1-5 all uses electric furnace smelting to obtain, specific chemical composition such as table 1
Shown in.The Cast Strip thickness obtaining after thin strap continuous casting, Cast Strip cooldown rate, hot rolling finishing temperature, hot rolling
Reduction ratio, hot-rolled strip thickness, hot-rolled strip cooldown rate, coiling temperature, cold rolling reduction ratio, annealing temperature
Degree, the technological parameter such as annealing time is shown in Table 2, and the tensile property of hot-rolled strip and high-strength tie is shown in Table
3。
Fig. 1 show the microscopic structure of thin strap continuous casting hot-rolled strip in embodiment 1, by the pearlite of 92%,
And polygonal ferrite and acicular ferrite are constituted on a small quantity, for after typical hot rolling, recrystallization do not occur
Austenite phase transformation after the microstructure characteristic that obtains.
Fig. 2 is the cementite lamella of thin strap continuous casting hot-rolled strip microscopic structure medium pearlite in embodiment 1,
Cemetite lamellae layer thickness is nanometer scale, and cemetite lamellae interlamellar spacing is sub-micrometer scale.
Fig. 3 is microscopic structure after cold rolling for the hot-rolled strip in embodiment 1, can be at ferrite and pearlite
Observing Zona transformans in crystal grain, crystal grain, along rolling to substantially being elongated, is distributed in threadiness.Pearlite
In cementite also there occurs plastic deformation, be parallel to roll to cementite be elongated, be perpendicular to roll to
Cementite bend.Having no any micro-crack inside cold rolling strap, quality is fine.
Fig. 4 is the microscopic structure in embodiment 1 after cold rolling strap annealing, is the ferrite base of recovery annealing
On body, Dispersed precipitate cementite particle or the cementite stub of a diameter of nanometer scale, so that high
Strong tie has excellent strong plasticity coupling.
From table 3 it can be seen that the tensile strength >=1000MPa of the high-strength tie of the present invention, elongation percentage >=
12%。
Table 1 unit: wt.%
| Embodiment | C | Si | Mn | P | S | N |
| 1 | 0.29 | 0.23 | 1.31 | 0.014 | 0.008 | 0.0057 |
| 2 | 0.33 | 0.35 | 1.44 | 0.015 | 0.002 | 0.0062 |
| 3 | 0.40 | 0.16 | 1.78 | 0.011 | 0.004 | 0.012 |
| 4 | 0.36 | 0.32 | 2.00 | 0.012 | 0.003 | 0.0098 |
| 5 | 0.25 | 0.40 | 1.69 | 0.014 | 0.005 | 0.0076 |
Table 2
Table 3
Claims (13)
1. the high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa, its chemical component weight percentage
Ratio is: C 0.25-0.40%, Si 0.15-0.40%, Mn 1.3-2.0%, P≤0.015%, S≤
0.01%, N≤0.012%, remaining is Fe and inevitable impurity；
The manufacture method of the high-strength tie of described thin strap continuous casting economy comprises the steps:
1) Cast Strip using twin-roll thin strip continuous casting cast thickness to be 1.0-5.0mm, its chemical composition
Percentage by weight is described above；
2) cooling down Cast Strip, cooldown rate is 20-80 DEG C/s；
3) online hot rolling, finishing temperature >=900 DEG C, hot rolling reduction ratio≤10%, hot rolling are carried out to Cast Strip
The thickness of rear steel band is 0.9-5.0mm；
4) cooling down hot-rolled strip, cooldown rate is 10-50 DEG C/s；
5) batching hot-rolled strip, coiling temperature is 630-730 DEG C；Hot-rolled strip microscopic structure is by 80%
Above pearlite, and a small amount of polygonal ferrite and acicular ferrite composition, and pearlite
Middle cemetite lamellae layer thickness is nanometer scale, and cemetite lamellae interlamellar spacing is nanometer or sub-micron amount
Level；
6) carrying out cold rolling to hot-rolled strip, cold rolling reduction ratio is 65-75%, and cold rolling rear thickness of strips is
0.3-1.2mm；
7) carrying out blue annealing to cold rolling strap, annealing temperature is 500-550 DEG C, and annealing time is
120-180s；Microscopic structure after cold rolling strap annealing, is on the ferrite matrix of recovery annealing
Dispersed precipitate cementite particle or the cementite stub of a diameter of nanometer scale；Steel band
Tensile strength >=1000MPa, elongation percentage >=12%.
2. the high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 1,
It is characterized in that: the content range of C is 0.28-0.38%, by weight percentage.
3. the high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 1,
It is characterized in that: the content range of Mn is 1.5-1.8%, by weight percentage.
4. the high-strength tie of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 1,
It is characterized in that: the content range of Si is 0.25-0.35%, by weight percentage.
5. the thin strap continuous casting economy high-strength tie manufacture method of tensile strength >=1000MPa, including walk as follows
Rapid:
1) Cast Strip using twin-roll thin strip continuous casting cast thickness to be 1.0-5.0mm, its chemical composition
Percentage by weight is: C 0.25-0.40%, Si 0.15-0.40%, Mn 1.3-2.0%, P≤
0.015%, S≤0.01%, N≤0.012%, remaining is Fe and inevitable impurity；
2) cooling down Cast Strip, cooldown rate is 20-80 DEG C/s；
3) online hot rolling, finishing temperature >=900 DEG C, hot rolling reduction ratio≤10%, hot rolling are carried out to Cast Strip
The thickness of rear steel band is 0.9-5.0mm；
4) cooling down hot-rolled strip, cooldown rate is 10-50 DEG C/s；
5) batching hot-rolled strip, coiling temperature is 630-730 DEG C；Hot-rolled strip microscopic structure is by 80%
Above pearlite, and a small amount of polygonal ferrite and acicular ferrite composition, and pearlite
Middle cemetite lamellae layer thickness is nanometer scale, and cemetite lamellae interlamellar spacing is nanometer or sub-micron amount
Level；
6) carrying out cold rolling to hot-rolled strip, cold rolling reduction ratio is 65-75%, and cold rolling rear thickness of strips is
0.3-1.2mm；
7) carrying out blue annealing to cold rolling strap, annealing temperature is 500-550 DEG C, and annealing time is
120-180s；Microscopic structure after cold rolling strap annealing, is on the ferrite matrix of recovery annealing
Dispersed precipitate cementite particle or the cementite stub of a diameter of nanometer scale；Steel band
Tensile strength >=1000MPa, elongation percentage >=12%.
6. the high-strength tie system of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 1) in, the content range of C is 0.28-0.38%, with
Percentage by weight meter.
7. the high-strength tie system of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 1) in, the content range of Mn is 1.5-1.8%, with
Percentage by weight meter.
8. the high-strength tie system of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 1) in, the content range of Si is 0.25-0.35%, with
Percentage by weight meter.
9. the high-strength tie system of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 2) in, Cast Strip cooldown rate is 30-60 DEG C/s.
10. the high-strength tie system of thin strap continuous casting economy of tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: state step 3) in, hot rolling reduction ratio is 5-10%.
The high-strength tie system of thin strap continuous casting economy of 11. tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 4) in, hot-rolled strip cooldown rate is 10-40 DEG C/s.
The high-strength tie system of thin strap continuous casting economy of 12. tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: described step 5) in, the tensile strength of hot-rolled strip is 630-680MPa,
Elongation percentage >=15%.
The high-strength tie system of thin strap continuous casting economy of 13. tensile strength >=1000MPa as claimed in claim 5
Make method, it is characterized in that: increase step 8 as required) carry out painting or zinc-plated follow-up to steel band
Process.
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| CN104878178B (en) * | 2015-05-08 | 2017-06-13 | 武汉钢铁江北集团有限公司 | A kind of production method of tensile strength >=1000 MPa ties |
| CN110358976A (en) * | 2019-08-22 | 2019-10-22 | 江苏沙钢集团有限公司 | A kind of high-carbon steel strip and its production method |
| CN113430468A (en) * | 2021-06-24 | 2021-09-24 | 江苏沙钢集团有限公司 | Thin-gauge high-strength steel with yield strength of 800MPa and production method thereof |
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| CN101363078A (en) * | 2008-09-25 | 2009-02-11 | 上海宝钢包装钢带有限公司 | Heat treatment method of steel belt for packages and steel belt for packages |
| CN101781735A (en) * | 2009-01-16 | 2010-07-21 | 宝山钢铁股份有限公司 | Economical high-strength binding strip steel with tensile strength more than or equal to 1,000 MPa, and manufacturing method thereof |
| CN103305753A (en) * | 2012-03-14 | 2013-09-18 | 宝山钢铁股份有限公司 | Manufacturing method of thin-strip continuous casting low-carbon micro-alloy steel strip |
| CN103757531A (en) * | 2014-01-24 | 2014-04-30 | 宝山钢铁股份有限公司 | Thin strip continuous casting economic high-strength binding strip with tensile strength of at least 1000 MPa and manufacturing method thereof |
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| CN101363078A (en) * | 2008-09-25 | 2009-02-11 | 上海宝钢包装钢带有限公司 | Heat treatment method of steel belt for packages and steel belt for packages |
| CN101781735A (en) * | 2009-01-16 | 2010-07-21 | 宝山钢铁股份有限公司 | Economical high-strength binding strip steel with tensile strength more than or equal to 1,000 MPa, and manufacturing method thereof |
| CN103305753A (en) * | 2012-03-14 | 2013-09-18 | 宝山钢铁股份有限公司 | Manufacturing method of thin-strip continuous casting low-carbon micro-alloy steel strip |
| CN103757531A (en) * | 2014-01-24 | 2014-04-30 | 宝山钢铁股份有限公司 | Thin strip continuous casting economic high-strength binding strip with tensile strength of at least 1000 MPa and manufacturing method thereof |
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