CN104233067B - Hot-dip galvanized steel sheet with high work hardening index for automobiles - Google Patents
Hot-dip galvanized steel sheet with high work hardening index for automobiles Download PDFInfo
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- CN104233067B CN104233067B CN201410466697.1A CN201410466697A CN104233067B CN 104233067 B CN104233067 B CN 104233067B CN 201410466697 A CN201410466697 A CN 201410466697A CN 104233067 B CN104233067 B CN 104233067B
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Abstract
The invention discloses a hot-dip galvanized steel sheet with a high work hardening index for automobiles. The hot-dip galvanized steel sheet comprises the following chemical components in percentage by mass: not less than 0.003% and not more than 0.005% of C, not more than 0.1% of Mn, not more than 0.01% of Si, not more than 0.02% of P, not less than 2.67 of S/C, not more than 0.015% of S, not less than 0.02% and not more than 0.07% of Alt, not more than 0.004% of N, not less than 0.02% and not more than 0.06% of Ti-4C-1.5S-3.42N, not more than 0.02% of Cu+Cr+Ni, and the balance of Fe and microelements. According to the steel sheet, the sulphur content in the steel-making process is adjusted by composition proportion, production is carried out on the basis of optimization of a hot rolling process, and the hot-dip galvanized steel sheet has relatively high work hardening index n90 value, and can meet the production requirements of drawing and bulging automobile sheets.
Description
Technical field
The application relates to metal material processing field, particularly relates to a kind of high work hardening index hot dip of automobile
Zinc steel plate.
Background technology
Gap-free atom automobile high work hardening index hot-dip galvanizing sheet steel (DX54D+Z), the existing company of employing in a large number
Continuous annealing process produces, and it is used for auto industry, shapes including many drawing-swollen types and (is called for short auxetic
Shape) part, such as: door inner panel, beater or beat-up, floor side member etc., by CB/T 2518-2008 to similar steel
The requirement planted, its chemical composition mass percent is: C≤0.12%, Mn≤0.60%, Si≤0.50%, P
≤ 0.10%, S≤0.045%, Ti≤0.30%, surplus is Fe.It is surrendered by GB CB/T 2518-2008
Requirement of strength 120MPa≤Rel≤220MPa, tensile strength requires 260MPa≤Rm≤350MPa, has no progeny
Percentage elongation requires A80 >=36%, n90 >=0.18, r90 >=1.6.To its composition in Europe superscript EN10346-2009
Requiring to be C≤0.12%, Mn≤0.60%, S≤0.50%, P≤0.10%, Ti≤0.30%, its performance is wanted
Ask as yield strength 120MPa≤Rel≤220MPa, tensile strength 260MPa≤Rm≤350MPa, have no progeny
Percentage elongation requires A80 >=36%, n90 >=0.17, r90 >=1.6.For this steel grade, generally produce acquisition
Rel is in the range of 140-200MPa, and A80 >=41%, n90 is in the range of 0.19-0.23, and r90 is at 2.2-2.7
In the range of, and when auxetic shapes, often require that Rel≤180MPa, and A80 >=43%, n90 >=0.23, r90 >=
2.0.Therefore the work hardening index n90 value of this steel grade is on the low side at present, it is more difficult to meet the requirement that auxetic shapes.
Summary of the invention
The present invention provides a kind of high work hardening index hot-dip galvanizing sheet steel of automobile, it is therefore intended that overcome existing nothing
Interstitial atom automobile is on the low side by high work hardening index hot-dip galvanizing sheet steel work hardening index n90 value, is unfavorable for
The problem carrying out auxetic shaping.
For solving above-mentioned technical problem, the invention provides a kind of high work hardening index hot-galvanized steel of automobile
Plate, described hot-dip galvanizing sheet steel chemical composition mass percent is: 0.003%≤C≤0.005%, Mn≤0.1%,
Si≤0.01%, P≤0.02%, S/C >=2.67, S≤0.015%, 0.02%≤Alt≤0.07%, N≤0.004%,
0.02%≤Ti-4C-1.5S-3.42N≤0.06%, Cu+Cr+Ni≤0.02%, surplus is Fe and trace element.
Preferably, the automobile production method of high work hardening index hot-dip galvanizing sheet steel includes:
Molten iron is obtained slab by smelting；
Being heated by slab, heating-up temperature is 1100 DEG C～1200 DEG C；
Slab after heating obtains hot rolled plate through roughing and finish rolling, and the total reduction of last three passages of finish rolling >=
0.5。
Being cooled down by described hot rolled plate, be curled into hot rolled coil after cooling, coiling temperature is 740 DEG C ± 20 DEG C；
By described hot rolled coil by the chill volume of cold rolling acquisition；
Described chill volume through continuous annealing and zinc-plated is obtained described hot-dip galvanizing sheet steel.
By one or more technical scheme of the present invention, the invention have the advantages that or advantage:
A kind of automobile high work hardening index hot-dip galvanizing sheet steel, the chemical composition percent mass that the present invention provides
Number is: 0.003%≤C≤0.005%, Mn≤0.1%, Si≤0.01%, P≤0.02%, S/C >=2.67,
S≤0.015%, 0.02%≤Alt≤0.07%, N≤0.004%, 0.02%≤Ti-4C-1.5S-3.42N≤0.06%,
Cu+Cr+Ni≤0.02%, surplus is Fe and trace element.This steel plate, mainly by composition proportion, adjusts
The sulfur content of steelmaking process, produces on the basis of being optimized hot rolling technology, has processing hardening
The feature that index n90 value is higher, it is possible to meet the production needs of auxetic shaped automotive plate.
Accompanying drawing explanation
Fig. 1 is the automobile solid solution carbon in high work hardening index hot-dip galvanizing sheet steel related in the embodiment of the present invention
In-fighting peak value figure；
Fig. 2 is the superfluous titanium impact on hot rolled coil crystallite dimension in the embodiment of the present invention；
Fig. 3 is that the automobile TiC in high work hardening index hot-dip galvanizing sheet steel in the embodiment of the present invention is at ferrum element
Solubility product curve chart in body；
Fig. 4 is the precipitate photo recorded by transmission electron microscope in the embodiment of the present invention；
Fig. 5 is the metallographic structure photo in the embodiment of the present invention.
Detailed description of the invention
In order to make the application the technical staff in the technical field be more clearly understood that the application, below in conjunction with
Accompanying drawing, is described in detail technical scheme by specific embodiment.
In general, the automobile work hardening index of high work hardening index hot-dip galvanizing sheet steel depends on its
Precipitate quantity, precipitate kind and crystallite dimension.Granular Second Phase Precipitation thing separates out at intra-die
The most abundant, grain size size is the biggest, and work hardening index value is the biggest.
The present invention mainly introduces the high work hardening index hot-dip galvanizing sheet steel of automobile, by automobile height processing
The optimization design of hardenability value hot-dip galvanizing sheet steel composition, adjusts and optimizes hot-rolled process parameter, successfully producing
Automobile is with high work hardening index hot-dip galvanizing sheet steel.The automobile that the present invention provides is with high work hardening index hot dip
The chemical composition mass percent of zinc steel plate is: 0.003%≤C≤0.005%, Mn≤0.1%, Si≤0.01%,
P≤0.02%, S/C >=2.67, S≤0.015%, 0.02%≤Alt≤0.07%, N≤0.004%, 0.02%
≤ Ti-4C-1.5S-3.42N≤0.06%, Cu+Cr+Ni≤0.02%, surplus is Fe and trace element.
The composition design principle of the present invention is as follows:
C: owing to carbon exists with interstitial atom and cementite form in ferrite, has strong strong in steel
Change effect, is unfavorable for plastic deformation.In order to reduce the automobile surrender with high work hardening index hot-dip galvanizing sheet steel
Intensity and raising elongation percentage, must strictly control carbon content.If but carbon content is the lowest, be then unfavorable for
IF steel is formed Second Phase Precipitation thing TiC and Ti of more disperse4C2S2, it is unfavorable for that improving processing hardening refers to
Number.Therefore the mass percent of C is controlled 0.003%～0.005% by the present invention.Internal Friction Meter is utilized to measure
Solid solution carbon in-fighting peak value as shown in Figure 1.
P, Mn and Si: phosphorus, manganese and silicon are all the intensified elements in steel, are typically solid-solubilized in ferrite, right
Punching performance is unfavorable, and the FeTiP that the highest meeting of P content causes needle-like separates out, and refers to improving processing hardening
Number is unfavorable.Therefore the mass percent of Si is controlled below 0.01% by the present invention, the percent mass numerical control of Mn
System is below 0.1%, and the mass percent of P controls below 0.02%.
S: sulfur is the harmful element in steel, and content is the highest can induce brittle fracture, the most typically requires that it is at steel
In mass percent less than 0.015%.If but S content is the lowest, then cannot be formed in the hot rolling
Enough Ti4C2S2Precipitate, is unfavorable for improving work hardening index, therefore it is required that the atomic ratio of S and C is big
In 1, being converted into mass percent than then is 2.67≤S/C.Solid solution carbon in steel matrix and the stable control of sulfur content
Be made as precipitate stablizes the guarantee that provides the foundation.
Alt: aluminum is the deoxidizer in steel-making, if content is less than 0.02%, cannot completely remove the oxygen in steel
Compound, such as SiO2And MnO, cause processing characteristics to be greatly lowered.If it exceeds 0.07% is substantially saturated.
N: nitrogen is essentially identical with the effect of carbon, has strong invigoration effect, it is therefore desirable to controlled by its content
In the extremely low level that state-of-the art can reach, the present invention requires≤0.004%.
Superfluous titanium Ti-4C-1.5S-3.42N: titanium has important effect in gapless atomic steel, can be in refining
In steel and course of hot rolling, the carbon in steel, nitrogen and sulfur are combined formation second phase particles such as TiC and analyse in crystal grain
Go out, thoroughly eliminate carbon, nitrogen and the sulfur adverse effect to steel plate punched performance, the therefore superfluous titanium of general requirement
(Ti-4C-1.5S-3.42N) can not be the lowest.Meanwhile, superfluous titanium (i.e. Ti-4C-1.5S-3.42N) content is to hot rolling
Crystallite dimension has large effect, as in figure 2 it is shown, and bigger hot rolling crystallite dimension is conducive to improving processing
Hardenability value.Therefore the mass percent of superfluous titanium (Ti-4C-1.5S-3.42N) is controlled by the present invention
0.02%-0.06%.
Ni, Cu, Cr: these three element broadly falls into the impurity element that raw band in steelmaking process enters, typically
Production does not has specific requirement.Generally it is solid-solubilized in ferrite and plays certain invigoration effect.Miscellaneous in order to reduce
Prime element, on the automobile impact of high work hardening index hot-dip galvanizing sheet steel yield strength, needs in raw material
The these three constituent content upper limit makes regulation, requires Cu+Cr+Ni≤0.02% in the present invention.
The automobile the comprising mentioned component producer of high work hardening index hot-dip galvanizing sheet steel that the present invention provides
Method specifically includes following step:
Molten iron is obtained slab by smelting；
Being heated by slab, heating-up temperature is 1100 DEG C～1200 DEG C；
Slab after heating obtains hot rolled plate through roughing and finish rolling, and the total reduction of last three passages of finish rolling >=
0.5。
Then being cooled down by hot rolled plate, be curled into hot rolled coil after cooling, coiling temperature is 740 DEG C ± 20 DEG C；
By hot rolled coil by the chill volume of cold rolling acquisition；
Chill volume through continuous annealing and zinc-plated is obtained the high work hardening index hot-dip galvanizing sheet steel of automobile.
The production method principle of the present invention is as follows:
Slab heating temperature: slab heating temperature is adjusted to 1100 DEG C～1200 DEG C by the present invention, this temperature range
Make Ti4S2C2Precipitate will not dissolve in rough rolling process again, and the precipitation for TiC provides guarantee.
The total reduction of last three passages of finish rolling: the total reduction of last for finish rolling three passages is adjusted to by the present invention
>=0.8, this reduction ratio may insure that and stores enough straiies energy of distortion in the strip steel of finish rolling outlet, can be rear
Continuous coiling process excites the precipitation of TiC particle.
Coiling temperature: coiling temperature is adjusted to 720 DEG C～760 DEG C by the present invention, and this temperature range makes TiC permissible
Fully separate out.TiC solubility product curve in ferrite is as shown in Figure 3.
Utilize the high work hardening index hot-dip galvanizing sheet steel of a kind of automobile that the present invention provides, it is thus achieved that automobile use
High work hardening index hot-dip galvanizing sheet steel work hardening index is more than 0.23.
The present invention, by being optimized to set up meter separately, adjusts and optimizes hot-rolled process parameter, successfully produces automobile and uses
High work hardening index hot-dip galvanizing sheet steel (DX54D+Z), the automobile produced is with high work hardening index hot dip
Zinc steel plate has the feature of high work hardening index, can bring considerable economic benefit.
Embodiment 1:
The high work hardening index hot-dip galvanizing sheet steel of automobile produced according to the method provided in the present invention, its
Chemical composition mass percent is: C:0.005%, Mn:0.1%, Si:0.010%, P:0.02%, S:
0.015%, S/C:3, Alt:0.07%, N:0.004%, Ti-4C-1.5S-3.42N:0.06%, Cu+Cr+Ni:
0.02%, surplus is Fe and trace element.The production technology of this Automobile Plate steel is first to be smelted by molten iron
Obtaining steel billet, then heat slab, slab heating temperature is 1200 DEG C, last three passages of finish rolling total
Reduction ratio is 0.5, and coiling temperature is 720 DEG C, through cold rolled annealed zinc-plated after last obtain specification be 0.5 ×
The automobile of 1000mm is with high work hardening index hot-dip galvanizing sheet steel.Its mechanical property is as shown in table 1.Utilize thoroughly
Radio mirror records the TiC precipitate in the strip steel after annealing as shown in Figure 4.Band crystalline grain of steel such as Fig. 5 after annealing
Shown in.
Table 1
| Re,MPa | Rm, MPa | A80, % | n90 | r90 |
| 154 | 294 | 45 | 0.23 | 2.23 |
| 158 | 299 | 44 | 0.23 | 2.35 |
| 152 | 301 | 43 | 0.23 | 2.54 |
| 149 | 289 | 44 | 0.24 | 2.78 |
Embodiment 2:
The high work hardening index hot-dip galvanizing sheet steel of automobile produced according to the method provided in the present invention, its
Chemical composition mass percent is: C:0.003%, Mn:0.05%, Si:0.007%, P:0.01%, S:
0.008%, S/C:2.67, Alt:0.04%, N:0.002%, Ti-4C-1.5S-3.42N:0.04%, Cu+Cr+Ni:
0.01%, surplus is Fe and trace element.Slab heating temperature is 1100 DEG C, last three passages of finish rolling total
Reduction ratio is 0.7, and coiling temperature is 740 DEG C, through cold rolled annealed zinc-plated after the last specification that obtains be
The automobile of 0.7 × 1200mm is with high work hardening index hot-dip galvanizing sheet steel.Its mechanical property is as shown in table 2.
Table 2
| Re,MPa | Rm, MPa | A80, % | n90 | r90 |
| 143 | 278 | 47 | 0.25 | 2.74 |
| 145 | 277 | 46 | 0.24 | 2.68 |
| 143 | 270 | 45 | 0.24 | 2.59 |
Embodiment 3:
The high work hardening index hot-dip galvanizing sheet steel of automobile produced according to the method provided in the present invention, its
Chemical composition mass percent is: C:0.004%, Mn:0.08%, Si:0.008%, P:0.015%, S:
0.013%, S/C:3.25, Alt:0.05%, N:0.003%, Ti-4C-1.5S-3.42N:0.02%, Cu+Cr+Ni:
0.015%, surplus is Fe and trace element.Slab heating temperature is 1150 DEG C, last three passages of finish rolling total
Reduction ratio is 0.8, and coiling temperature is 760 DEG C, and steel plate specification is 0.8 × 1450mm.Its mechanical property such as table
Shown in 3.
Table 3
| Re,MPa | Rm, MPa | A80, % | n90 | r90 |
| 150 | 284 | 44.5 | 0.23 | 2.45 |
| 153 | 280 | 44 | 0.24 | 2.58 |
| 143 | 276 | 45.5 | 0.25 | 2.34 |
| 145 | 281 | 45 | 0.25 | 2.49 |
By one or more embodiment of the present invention, the invention have the advantages that or advantage:
A kind of automobile high work hardening index hot-dip galvanizing sheet steel, the chemical composition percent mass that the present invention provides
Number is: 0.003%≤C≤0.005%, Mn≤0.1%, Si≤0.01%, P≤0.02%, S/C >=2.67,
S≤0.015%, 0.02%≤Alt≤0.07%, N≤0.004%, 0.02%≤Ti-4C-1.5S-3.42N≤0.06%,
Cu+Cr+Ni≤0.02%, surplus is Fe and trace element.This steel plate, mainly by composition proportion, adjusts
The sulfur content of steelmaking process, produces on the basis of being optimized hot rolling technology, has processing hardening
The feature that index n90 value is higher, it is possible to meet the production needs of auxetic shaped automotive plate.
Although having been described for the preferred embodiment of the application, but one of ordinary skilled in the art once learning
Basic creative concept, then can make other change and amendment to these embodiments.So, appended power
Profit requires to be intended to be construed to include preferred embodiment and fall into all changes and the amendment of the application scope.
Obviously, those skilled in the art can carry out various change and modification without deviating from this Shen to the application
Spirit and scope please.So, if the application these amendment and modification belong to the application claim and
Within the scope of its equivalent technologies, then the application is also intended to comprise these change and modification.
Claims (1)
1. an automobile is with high work hardening index hot-dip galvanizing sheet steel, it is characterised in that described hot-dip galvanizing sheet steel
Chemical composition mass percent is:
0.003%≤C≤0.005%, Mn≤0.1%, Si≤0.01%, P≤0.02%, S/C >=2.67, S
≤ 0.015%, 0.02%≤Alt≤0.07%, N≤0.004%, 0.02%≤Ti-4C-1.5S-3.42N≤0.06%,
Cu+Cr+Ni≤0.02%, surplus is Fe and trace element；
The production method of described hot-dip galvanizing sheet steel includes:
Molten iron is obtained slab by smelting；
Being heated by slab, heating-up temperature is 1100 DEG C～1200 DEG C；
Slab after heating obtains hot rolled plate through roughing and finish rolling, and the total reduction of last three passages of finish rolling >=
0.7；
Being cooled down by described hot rolled plate, be curled into hot rolled coil after cooling, coiling temperature is 740 DEG C ± 20 DEG C；
By described hot rolled coil by the chill volume of cold rolling acquisition；
Described chill volume through continuous annealing and zinc-plated is obtained described hot-dip galvanizing sheet steel.
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| CN201410466697.1A CN104233067B (en) | 2014-09-12 | 2014-09-12 | Hot-dip galvanized steel sheet with high work hardening index for automobiles |
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| CN101608284B (en) * | 2009-07-13 | 2011-09-28 | 山西太钢不锈钢股份有限公司 | Manufacturing method of titanium microalloyed hot rolled strip |
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Address after: 100041 Shijingshan Road, Shijingshan District, Shijingshan District, Beijing Patentee after: Shougang Group Co. Ltd. Address before: 100041 Shijingshan Road, Shijingshan District, Shijingshan District, Beijing Patentee before: Capital Iron & Steel General Company |
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