Summary of the invention
Present invention aim to provide a kind of high molding high durable Ultra-thin hot rolled steel plate and CSP thereof to produce work
Skill, this thin specification steel plate not only intensity is high, and mouldability and weather resistance are excellent, and this technique reduces CSP production line and produces
Continuous casting bleed-out rate during high-strength Thin Specs steel.
For achieving the above object, the technical solution used in the present invention is: a kind of high molding high durable Ultra-thin hot-rolled steel
Plate, chemical composition and the weight percent content thereof of this steel plate are as follows: C:0.035～0.065%, Si:0.15～0.3%, Mn:
1.3～1.6%, Cu:0.12～0.2%, Cr:0.2～0.6%, Ni:0.1～0.2%, Ti:0.1～0.13%, Mo:0.1～
0.2%, Als:0.025～0.045%, following control of element exists: P:0～0.018%, S:0～0.005%, N:0～
0.006%, remaining is Fe and inevitable impurity.
Further, chemical composition and the weight percent content thereof of this steel plate are as follows: C:0.035～0.065%, Si:
0.2～0.3%, Mn:1.3～1.6%, Cu:0.12～0.2%, Cr:0.3～0.5%, Ni:0.1～0.2%, Ti:0.1～
0.13%, Mo:0.1～0.2%, Als:0.025～0.045%, following control of element exists: P:0～0.018%, S:0～
0.005%, N:0～0.006%, remaining is Fe and inevitable impurity.
Further, chemical composition and the weight percent content thereof of this steel plate are as follows: C:0.035～0.05%, Si:
0.2～0.3%, Mn:1.3～1.5%, Cu:0.12～0.2%, Cr:0.3～0.4%, Ni:0.15～0.2%, Ti:0.1～
0.13%, Mo:0.1～0.2%, Als:0.03～0.045%, following control of element exists: P:0～0.01%, S:0～
0.005%, N:0～0.005%, remaining is Fe and inevitable impurity.
Further, described steel plate thickness is 1.2～2.0mm.
The production method of a kind of above-mentioned high molding high durable Ultra-thin hot-rolled steel, including converter smelting, external refining, company
Casting, soaking, roll and control cold step, described converter smelting, the weight percent content of the P that taps after controlling to smelt be 0～
0.012%；Described continuous casting, it is 2.45～2.55mw/m that crystallizer hot-fluid controls2, it is 1.77 that the specific water of continuous casting secondary cooling water controls
～1.83L/Kg, opening and watering thickness of strand is 65～75mm, depresses to 55～60mm through repeatedly wick-containing；Described soaking, controls casting
Base tapping temperature is 1230～1250 DEG C；Described rolling, controlling finishing temperature is 880～920 DEG C；Described control is cold, cold through laminar flow
Batch the most afterwards, use the head ladder type of cooling, batch after rolling off the production line with the cooling rate of≤10 DEG C/S slowly cool to 280～
After 320 DEG C, more quickly cool down.
Further, described casting process, controlling covering slag basicity is 1.0～1.15, and viscosity is 1.42～1.65Pa.s,
Fusing point is 1030～1100 DEG C.
Further, described control is cold, and controlling Strip Steel Coiling Temperature before head 0.8～1.2m is 650～670 DEG C, head
Controlling coiling temperature after 0.8～1.2m is 610～630 DEG C.
Further, described control is cold, batches after slowly cooling to 295～305 DEG C with the cooling rate of 5～8 DEG C/S after rolling off the production line,
The most quickly cool down.
Chemical composition with regard to the present invention is analyzed illustrating below:
C: CSP is produced for line, C content 0.07～0.17% scope belong to peritectic steel, and CSP produces line continuous casting funnel
Type crystallizer, causes bleed-out and crackle risk to be greatly increased when casting peritectic steel because of peritectic reaction, must keep away for this CSP flow process
Opening peritectic steel scope, C content must be at C≤0.07%, or C >=0.17%；C is relatively big to improving intensity effect, but C content is relatively
Gao Shi, the welding performance of steel is deteriorated, it is desirable to the strip steel of welding, phosphorus content is usually no more than 0.2%；It addition, C dramatically increases steel
Cold brittleness and aging sensitivity, therefore the present invention considers high durable and the high-mouldability energy of high-strength steel, and producing line feature in conjunction with CSP will
C content controls 0.035～0.065%.
Mn: manganese can improve band hardness of steel by solution strengthening, under certain content, moreover it is possible to improves the toughness of steel and wear-resisting
Property, but when Mn content is more than 1.3%, continuous casting billet solidification processing forms segregation, cause the formation of pearlite band, in steel
Mn content is the highest, and banded structure is the most obvious, binding tests result, and Mn content is controlled 1.3～1.6% by the present invention.
Si: can be dissolved in ferrite and austenite, increases intensity and the hardness of steel, but the Si of too high amount is easily at oxygen
Changing iron sheet and the interface segregation of matrix, affect the control of surface quality, therefore, Si content controls 0.15～0.3%.
P: in the ordinary course of things, phosphorus is harmful element in steel, increases the cold brittleness of steel, makes welding performance degenerate, and reduction is moulded
Property, making cold-bending property degenerate, therefore usually require that in steel, phosphorus content is less than 0.045%, high-quality steel requires some more low, in the present invention
Finding during request test, P is also easily and Ti element forms the titanium iron phosphide of fragility at crystal boundary, weakens crystal boundary toughness, it is easy to lead
Causing intergranular crack etc., therefore, the present invention, in view of the high-mouldability energy of high-strength steel, controls P≤0.018%.
S: sulfur is the most also harmful element, makes steel produce red brittleness, reduces ductility and the toughness of steel, in forging
Causing crackle when making and roll, sulfur is the most unfavorable to welding performance, reduces corrosion resistance, so usually requiring that sulfur content is less than
0.055%, high-quality steel requires less than 0.040%；In addition to above-mentioned impact, in steel of the present invention, S Yu Ti is during casting blank solidification
Forming Ti4C2S2 large inclusions, reduce the precipitation strength effect of Ti, meanwhile, S is easily formed Containing Sulfur with Mo on crystal boundary
The low melting point eutectic product of molybdenum, causes crystal boundary fragility, and this can reduce mechanical property and the serviceability of steel further, it is contemplated that
CSP produces line feature and the high-mouldability energy requirement of high-strength steel, and the present invention controls S≤0.005%.
Ti:Ti is a kind of very important microalloy element, adds a certain amount of Ti content in steel, on the one hand can subtract
While few C equivalent, by crystal grain refinement and precipitation strength effect, significantly improve the intensity of steel, on the other hand, can by O in steel,
The foreign bodys such as N, S are fixed up, and improve the weldability of steel, and reducing N affects the aging sensitivity of steel, Ti 0.02～
During 0.15% scope, its content increases the effect to precipitation strength and refined crystalline strengthening clearly；And in the present invention, Ti is except right
Outside intensity has an impact, it also has a prior effect, and because Mo can promote the formation of M/A island constituent element, and M/A island is with martensite
It is main hard phase constitution, forms micro-crack when deformation at Yi M/A island/basal body interface, and crackle is also easy to along M-A island/base
Body interface extends, thus the plasticity and toughness to steel plate has a negative impact, and Ti microalloying can suppress M/A constituent element effectively
Formation, Ti with Mo is combined simultaneously, also advantageously improves the resistant to hydrogen erosiveness of strip steel, and for these reasons, the present invention controls
Ti controls 0.10～0.13% scope.
Mo: the crystal grain of steel can be made to refine, improves the quenching degree of steel, and in the present patent application, the effect of Mo is mainly: 1) pass through
The quenching degree of Mo, in conjunction with cooling controlling and rolling controlling process, increases carbon diffusion activation energy in austenite, reduces Carbon diffusion coefficient, from
And strongly hinder precipitation and the growth process of pro-eutectoid ferrite, promote the shape of the acicular ferrite of high density dislocation substructure
Becoming, especially under deformation condition, the interpolation of Mo can effectively facilitate acicular ferrite and be formed, and to improving, obdurability is highly effective,
Acicular ferrite is had preferable high intensity and high tenacity coordinates, and has higher compatibility of deformation ability, is conducive to improving into
Type performance；2) molybdenum can also improve the effect that the resistant to hydrogen of steel corrodes, and is allowed to not produce spot corrosion, so that strip steel is through acid cleaning process
After, reduce the generation of defect, it is to avoid the appearance of formation of crack；3) when Mo content is more than 0.2%, because of the quenching degree that it is strong, cause
Finished strip tissue occurring, M/A island is greatly increased, increases the fragility of steel, cause being greatly increased of cracking during bending probability, in conjunction with
Forming requirements, Mo content is controlled the scope in 0.10～0.2% by the present invention.
Cu: by forming the protective rust of densification on the surface of steel, hence it is evident that improve the corrosion resisting property of steel, work collaborative with Cr
With, corrosion resisting property is improved further, and it is more universal that weathering steel adds these two kinds of elements, but, Cu Yu Cr increases the deformation of steel and resists
Power, when Cu content is higher simultaneously, easily produces copper brittleness phenomenon, makes the surface of steel produce be full of cracks, and the fragility and the surface that increase steel are opened
Split probability；Meanwhile, copper bearing steel produces the most viscous iron scale in stove, affects the surface quality of steel, and the present invention considers
Above-mentioned impact, requires and correlation test result in conjunction with corrosion resisting property, and controlling Cu content is 0.12～0.2% scope.
Cr: chromium can significantly improve the intensity of steel, hardness, wearability and quenching degree, but reduce plasticity and the toughness of steel simultaneously.
Cr Yu Cu synergism substantially increases the corrosion resisting property of steel, considers that Cr (increases high-strength steel to roll on the impact of steel resistance of deformation simultaneously
Load processed is obvious), binding tests result, controlling Cr content range is 0.2～0.6%.
Ni: nickel not only can improve intensity and the corrosion resisting property of steel, also can keep good plasticity and toughness, in the present invention
In, Ni, in addition to being improved anti-corrosion effect, also helps reduction copper brittleness phenomenon.Copper bearing steel in soaking pit high-temperature oxidation process,
Because rich Cu liquid phase is to the osmosis of matrix, the degree of depth of formation reaches the surface fine fisssure caused by oxide on surface of 10～15 μm
Stricture of vagina, causes high-strength steel to produce cracking phenomena in follow-up clod wash loading process.And add 0.1～0.2% Ni element after, carry
The fusing point of high copper-rich phase, weakens the infiltration that soaking pit high-temperature oxidation process liquid Cu is inside, reduces the generation of crizzle,
The surface quality of final products and processability will not be produced impact.
Als: have deoxidation, crystal grain thinning in steel, improves toughness and prevents the effect of timeliness, but Als too high levels shadow
Ringing the surface quality of steel, also increase cost, accordingly, it is 0.025～0.045% scope that the present invention controls Als content.
N: form thick TiN in steel with Ti during casting blank solidification, on the one hand reduces the precipitation strength effect of Ti
Really；On the other hand, the existence that TiN is mingled with bulky grain in steel, affect the processability of steel, significantly reduce the plasticity of steel；With
Time, there is timeliness effect in N, makes the hardness of steel and intensity raise, and solderability and cold brittleness increase, and belong to harmful unit in the present invention
Element, produces line traffic control level in conjunction with CSP, it is desirable to N≤0.006%.
Compared with prior art, the invention have the advantages that
One, the present invention passes through appropriate design steel grades so that it is finished product is organized as acicular ferrite+polygon ferrum element
Body, then coordinate low P, low S and low N to control, not only make high-strength steel sheet have high tenacity concurrently, and metallographic structure crystal grain is thin and equal
Even, steel excellent surface quality, it is thus achieved that excellent compatibility of deformation ability, thus improve the processability of steel plate.
Its two, the present invention plays the advantage of CSP abbreviated system, makes full use of the precipitation of Ti+Mo element
Strengthening and build up effect, it is ensured that mechanical property and processability, in conjunction with the addition of Cu+Cr+Ni weathering element, produce thickness
＜ 2.0mm is thick, the high molding high weather resistance steel of yield strength 700MPa rank；Utilize simultaneously and produce the spy that line temperature control precision is high
Point, it is to avoid containing the fluctuation on Ti Steel Properties, can meet complexity while the high intensity and high-weatherability of stable acquisition steel plate
Forming requirements, this high-strength thin material is the high value added product of function admirable, can be widely applied to " with hot Dai Leng " and " with thin generation
Thick " high-strength thinning application, such as: can be used for container, railcar, passenger vehicle and vehicle with high-strength thinning field.
Its three, present invention process, production process controls stable, and continuous casting bleed-out rate is reduced to less than 1%, solves restriction
CSP produces line and produces a big technical bottleneck of high-strength thin material.