DE102006058917A1 - High strength steel sheets with excellent ductility and method of making same - Google Patents

Abstract

Disclosed is a high strength ferrite martensite steel sheet having an excellent ductility, comprising: 0.05-0.15 wt% C; 0.15 weight percent or less of Si; 0.5-2.7 weight percent Mn; 0.1-0.7 weight percent Al; 0.005-0.03 weight percent P; 0.01-0.3 weight percent Sb; 0.002-0.02% by weight S; at least one member selected from the group consisting of 0.01-0.6 wt% Mo and 0.0005-0.0035 wt% B; and the equalization Fe and identical impurities.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The The present invention relates to a high-strength steel sheet and a Method for producing the same and in particular high-strength steel sheets with excellent ductility and galvanizing ability, which as steel material for an automotive application can be used, and a method of manufacturing the same.

2. Background

numerous Researchers in the automotive industry have dealt with it extensively reduce the weight of a vehicle body to the standards which is required by environmental regulations and overcome problems of natural resource depletion.

For example were done big Efforts to deliver high-strength steel sheets to the exhaust gas too Suppremieren and improve the efficiency of the fuel and to reduce the weight of the vehicle body.

Though become steel materials with a higher strength for the purpose the safety of users preferred, but they have a lower Deformability on. For The products with a complicated shape will deformability very lowered.

This can be easily deduced from the fact that the higher the Strength of the steel sheet is the more the yield stress elevated and the stronger it falls Drawability, which is represented by the r value.

Around to cope with such problems Various attempts have been made to both high strength as well as to achieve a high extensibility of these steel materials. For example, many studies have included multiphase steels high strength and high ductility, which are TRIP steel, which uses a transformation-induced plasticity phenomenon, dual-phase (DP) steel with a martensite ferrite matrix and TWIP steel containing a double phenomenon used.

Under the same applies to the DP steel as a preferred material with respect to Compressibility. In particular, DP steel, which by Continuous annealing followed by a gas jet cooling line (GCL), a low yield stress, high ductility and an outstanding bake hardening (BH) on.

Though have DP steels good ductility, but they have the disadvantage that the r values of these are relatively small, which means that the thermoforming properties thereof are not excellent.

For now is made of high strength steels requires that they have both a high extensibility and an excellent Contraction (i.e., a high r-value). This is true on high-strength steel sheets with a tensile strength of 440 MPa, 490 MPa, 590 MPa or more.

Various attempts have been made to increase the r-values of the DP steels and to improve the contraction property. For example, the Japanese Patent Publication No. 1991-097812 . 1991 to 09781 and 1993-209228 Method for increasing the r-values of cold-rolled steel sheets for deep drawing, which uses two cold rolling methods and two annealing methods.

The in the above mentioned However, patents disclosed methods are not for the high-strength, cold-rolled steel sheets with a tensile strength of more than 440 MPa suitable. Due to the cold rolling and annealing process, respectively performed twice Need to become, In addition, the procedures also have low profitability and require increased Material costs. Consequently, such processes are not mass produced suitable.

The information disclosed in this section of the background of the invention is for Ver In order to better understand the background of the invention, and should not be construed as an affirmative or any form of suggestion that this information constitutes prior art which is already known to one skilled in the art.

SUMMARY OF THE INVENTION

In In one aspect, the present invention provides a high strength DP steel which has excellent ductility and contraction property even with one cycle of a cold rolling and annealing process and can be made by a hot dip galvanizing process. This advantage can be determined by using effective quantities Elements containing Sb can be achieved.

In a preferred embodiment The present invention provides a high strength ferrite martensite sheet steel with an excellent deformability and contraction property, which has: 0.05-0.15 weight percent C; 0.15 Weight percent or less Si; 0.5-2.7 weight percent Mn; 0.1-0.7 weight percent al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element consisting of 0.01-0.6 weight percent Mo and 0,0005-0,0035 Weight percent B existing group is selected; and the compensation Fe (balance Fe) and identical impurities.

Preferably For example, such a steel sheet may be 0.15 wt% or less of at least one element consisting of Ti, Nb and V selected Group according to one Target tensile strength selected becomes.

A adequate γ-fiber orientation ((111) // RD alignment) of the ferrite matrix can be 0.35 volume percent or more and a reasonable die alignment ((100) <001>) can be 0.2 volume percent or less.

In In another aspect, the present invention provides a method for producing a high-strength steel sheet of a dual-phase structure with an excellent deformability and contraction property even with one cycle of the cold rolling and annealing process, which is the step of adding an effective amount of Sb to the development the cube alignment and the rotated cube alignment ((100) <011>) to suppremieren and to increase the development of the (111) // RD alignment.

at such a method the amount of Sb is preferably 0.3% by weight or less and preferably 0.01-0.3 Weight.

In In yet another aspect, the present invention provides Method for producing a high-strength steel sheet with a excellent deformability and excellent contraction property, which comprises the following steps: (a) supplying a slab, which has: 0.05-0.15 Weight percent C; 0.15 weight percent or less of Si; 0.5-2.7 weight percent Mn; 0.1-0.7 weight percent al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element consisting of 0.01-0.6 weight percent Mo and 0,0005-0,0035 Weight percent B existing group is selected; and the compensation Fe and identical foreign substances; (b) reheating the slab at 1050-1250 ° C; (c) hot rolling the slab to a reduction ratio at the last (final) level to be set at 10% or less; (d) winding of the hot rolled steel sheet at 600-750 ° C and then cold rolling of the wound Steel sheet; and (e) recrystallization annealing the cold rolled steel sheet and then quenching the recrystallization annealed steel sheet.

The recrystallization can preferably for 30-180 Seconds at 750-850 ° C are performed. Quenching may also be at a rate preferably of 15-2,000 ° C / s.

Corresponding can 0.15 weight percent or less of at least one element, which consists of the group consisting of Ti, Nb and V according to a Target tensile strength selected is to be added to deliver a slab.

In In another aspect, motor vehicles are delivered which include have described high-strength steel sheet.

It It should be understood that the term "vehicle" or "vehicle" or another similar term is used herein is used, including Motor vehicles in general, such as passenger cars, including off-road vehicles (SUV), buses, trucks, various business cars, watercraft, including a variety of boats and ships, aircraft and the like is. The present high-strength steel sheets are in particular be useful with a wide variety of motor vehicles.

Other Aspects of the invention will be discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The The present invention will be described with reference to certain exemplary embodiments same described in the accompanying drawings are illustrated in which:

1 Fig. 10 is a graph showing volume fractions of γ fiber orientation according to an amount of antimony added in Examples and Comparative Examples;

2 Fig. 12 is a graph showing volume fractions of cube orientation according to an amount of antimony added in Examples and Comparative Examples; and

3 is a graph showing the r values according to an amount of antimony added in Examples and Comparative Examples.

DETAILED DESCRIPTION

hereafter become preferred embodiments of the present invention now with reference to the accompanying drawings be described in detail.

As discussed above In one aspect, the present invention provides a high strength DP steel sheet, which has excellent ductility and contraction property having.

One preferred example of the steel sheet of the present invention is a high strength ferrite martensite sheet steel with an excellent ductility and excellent contraction property, which has: 0.05-0.15 weight percent C; 0.15 Weight percent or less Si; 0.5-2.7 weight percent Mn; 0.1-0.7 weight percent al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element consisting of 0.01-0.6 weight percent Mo and 0,0005-0,0035 Weight percent B existing group is selected; and the compensation Fe and identical foreign substances. Such a steel sheet consists of one Dual-phase structure of ferrite and martensite.

Of the Inventor of the present invention has studied the evolution of the microstructure, Recrystallization and development of phase transformation according to the species the alloying elements in cold rolled steel sheets and the states of the The manufacturing process studied to those with the conventional Technique associated problems to solve. While performing such Investigations confirmed the present inventor that the development of γ-phase alignment ((111 // RD), which has a direct effect on the r value, below the alloy components primarily by the amount of carbon C of the solid solution is impaired.

A certain amount of carbon (C) becomes the martensite which is necessary for obtaining a target tensile strength is. Consequently, the amount of carbon in the solid solution can be the production of carbides by using titanium (Ti), vanadium (V), niobium (Nb), etc. are reduced against the carbons of the solid solution which are not necessary to the formation of such a martensite are.

It is possible to develop a recrystallization texture of the final product, which after the recrystallization annealing process which is a method known in the art. However, the method still has limitations in controlling the texture due to the reduction in the amount of carbon of the solid solution.

Around these restrictive restrictions to manage something, The present inventor has researches on an optimal design the alloy components and a texture control with the Addition of components carried out which no additional Procedures required.

By his intensive investigations have been found by the present inventor That is, a high r value can be obtained when 0.3% by weight or less antimony (Sb) is used. This limited amount at Sb, the developments of α fiber orientation ((110) // RD) and cube orientation ((100) <001>) can suppress and increase the development of the (111) // RD alignment.

moreover it is well known that when adding antimony (Sb) to the steel material, in which l0ppm or less sulfur (S) is present as an impurity is the cube alignment developed and thereby the physical properties of the steel sheet improved.

Based on these facts, the present inventor has found that the developments of the cube alignment and rotated cube alignment (100) <011>) and the development of the (111) // RD alignment may increase if 10 ppm or more sulfur (S) and 0.3% by weight or less Antimony (Sb) are contained in the steel material.

Based On this principle, the present invention provides in another Aspect a method for producing a high strength steel sheet a dual-phase structure which has excellent ductility and excellent contraction property even with one cycle cold rolling and annealing comprising the step of adding an effective amount At Sb, the evolution of cube alignment and twisted cube orientation ((100) <011>) and to increase the development of the (111) // RD alignment.

In a preferred embodiment Thus, the amount of S can be 10ppm or more and the amount of Sb 0.3 weight percent or less. More preferably, the Amount of S 0,002-0,02 Weight percent and the amount of Sb 0.01-0.3 weight percent.

Especially becomes a slab containing the alloying elements as described above was, a hot rolling process with a reduction ratio in Final stage of a hot strip finishing mill, which is set to 10% or less. The hot-rolled sheet becomes one Kastenglühverfahren subjected to 600-750 ° C. The resulting, annealed Sheet is then subjected to a winding process.

The consequently, hot-rolled steel sheet is subjected to a pickling process and subjected to a cold rolling process of 65-75%. Subsequently, will the cold-rolled steel sheet a degreasing process, a recrystallization annealing for 30-180 seconds at 750-850 ° C and one Quenching method based at a speed of 15-2,000 ° C / s subjected to the characteristics of the quenching line.

The Main phase of the cold-rolled DP steel sheet, which is described in the above Process is composed of a ferrite matrix and bainite and martensite structures coexist in a ratio above one certain degree according to a Nominal tensile strength and cooling rate the annealing range.

In a more preferred embodiment For example, a high strength steel sheet can be manufactured in the following manner become. A slab with: 0.05-0.15 Weight percent C; 0.15 weight percent or less of Si; 0.5-2.7 weight percent Mn; 0.1-0.7 Weight percent Al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element, which consists of the 0.01-0.6 Weight percent Mo and 0.0005-0.0035 Weight percent B existing group is selected; and optionally 0.15 Weight percent Ti, Nb or V; and the balancing-Fe and identical Foreign substances, is a reheating process at 1050-1250 ° C and one Hot rolling process at a reduction ratio of 10% or less in the last state of the hot strip finishing mill subject to ribbon flatness and surface control. The Hot rolled steel sheet is wound up at 600-750 ° C. The resulting, hot rolled steel sheet is subjected to a cold rolling process at a reduction ratio of 65-75% in strength subjected to 1.4 mm. The cold rolled steel sheet will last for 30-180 seconds a recrystallization annealing process subjected to 750-850 ° C. Finally, the recrystallization annealed steel sheet is at a speed of 15-2,000 ° C / s quenched.

At the Nachwärmverfahren the slab can be warming at less than 1050 ° C increase the rolling force, which due to the rolling resistance due to the low temperature what is the feasibility of hot rolling through. In contrast, heating can help more than 1250 ° C it complicates the microstructures, volume fractions and texture controls to control the final product due to the micro-deposits which in the quantities through the increased Restoration of the solid solution are included.

The Hot rolling process contains by a front rolling process that the front of the hot strip finishing mill executes the rolling process, and thereby a rear rolling process that the rear of the Hot strip finishing mill performs the rolling process, and both methods affect the development of the texture of the final product out.

In affected both rolling the reduction ratio at the last (end) stand often the Ribbon flatness of the hot-rolled steel sheets, which has a close relationship with productivity having. Consequently, the reduction ratio in the last step of the Hot rolling limited to 10% or less.

As As described above, the hot rolled steel sheet is also added 600-750 ° C rolled up (rolled up). A temperature below 600 ° C can thereby cause a problem that the transformation structure, which during produced by the hot rolling process is not completely recrystallized. In contrast, a temperature over 750 ° C Problem with pickling due to an oxide layer of a dense Cause structure on the surface of a hot-rolled steel sheet is formed.

moreover is desired that the recrystallization annealing process at 750-850 ° C, because it is difficult the relationship to control the martensite phase, which for a certain degree of tensile strength is required when the recrystallization annealing outside of the above Area performed becomes.

moreover is desired that the glow time on 30-180 Seconds limited is. A glow for less than 30 seconds can prevent the cold-rolled structure from being completely annealed and can affect the temperature of the phase transformation. On the other hand, a glow for more reduce the overall profitability as 180 seconds, though it has a can reach ideal temperature.

The cooling method is also at a speed of 15-2,000 ° C / s after the Rekristallungsglühverfahren executed. A cooling speed, which is lower than the above-mentioned range, can Guarantee impede drive energy, which requires martensitic transformation becomes. In contrast, a cooling rate, which higher than the one mentioned above Scope is a achieving a commercially available and practically available result impossible do.

The through the above mentioned Manufactured steel sheet has a matrix structure, which consists of ferrite and martensite, and thus has characteristics on that the γ-fiber orientation ((111 // RD) the ferrite matrix is controlled to 0.35 volume percent or more and the cube orientation ((100) <001> to 0.2 volume percent or less is suppressed.

When next become the reasons for limiting the content of the respective alloying elements to a particular Area are described.

C: 0.05-0.15 weight percent

carbon can affect the ductility of steel. An excessive amount on carbon reduces the ductility.

moreover it moves from the inside of the ferrite to the austenite phase in the temperature range of the phase transformation and thus stabilizes the austenite phase.

There an amount exceeding 0.15% by weight depends on the formation the dual phase and reduces the weldability, it is desired that the carbon content is 0.15% by weight or less.

on the other hand An amount less than 0.05% by weight may not be the necessary Ensure strength.

Si: 0.15 wt% or less

silicon is an element for stabilizing the ferrite, which is the deposit of cementite suppressed and the ferrite break increased to the lengthening to improve, and strength by reinforcing the solid solution elevated.

An excessive amount Si causes a defective surface texture and sets the weldability down. It also reduces paintability due to production of oxides.

consequently 0.15 weight percent or less is preferred.

Mn: 0.5-2.7 weight percent

manganese is an element for stabilizing the austenite, which is the strength with the generation of a phase transformation at a low temperature elevated, such as needle-shaped Ferrite, bainite or martensite.

In spite of the phase transformation caused by the diffusional transformation it also, that a texture memory event by decreasing the ferrite area occurs.

If the amount added is less than 0.5% by weight it is difficult the cooling speed to control the suppression of the formation of ferrite, whereas if it is more than 2.7% by weight, the formation of the segmentation on the sheet during the hot rolling process, the reduction of weldability and causing hydrogen-induced embrittlement.

consequently is desired that the manganese content is 0.5-2.7 Weight percent is maintained.

Al: 0.1-0.7 weight percent

aluminum Like silicon, the deposition of cementite suppresses the conversion process to delay.

It elevated the ferrite break to the extension and does not use the chemical conversion coating property and the galvanizing capability down; however, it provides a cause of embrittlement.

moreover it lowers the effective yield through the solution enhancement along with the silicon, which during is added to the cold rolling process.

consequently is desired the aluminum content is limited to the range of 0.1-0.7 weight percent.

P: 0.005-0.03% by weight

phosphorus elevated the strength of the steel sheet through the solid reinforcement and plays a role of stabilizing the remaining austenite through the increase the carbon of the solid solution, which is caused by the suppression of oxide formation.

If it is added overly, it causes the reduction of weldability and local extensibility due to the grain boundary segregation of P, promotes the development of cube alignment and prevents the development of the (111) // RD alignment.

consequently is desired the phosphorus content is limited to the range of 0.005-0.03% by weight.

Sb: 0.01-0.3 weight percent

antimony promotes the formation of the (111) // RD alignment, which is an advantageous Textile for The r value is and prevents the formation of the cube alignments and rotated Cube orientations. These effects are increased if silicon (S) is contained within a reasonable range.

If it is added overly, it affects steelmaking and hot rolling.

consequently is desired that the antimony content is limited to the range of 0.01-0.3 wt%.

S: 0.002-0.02% by weight

If Sulfur is added in a reasonable range, the effect of the same elevated. If it's overly added but forms coarse MnS on the hot rolled steel sheet, what leads to cracks. Consequently, it is desired that the sulfur content ranges from 0.002-0.02% by weight limited is.

Mo: 0.01-0.6 weight percent

Molybdenum is like Mn an element which phase transition with a low Temperature stabilized. If it is overly added, put it down the ductility. Consequently, it is desired that the molybdenum content to the range of 0.01-0.6 Weight percent limited is.

B: 0.0005-0.0035 weight percent

boron like Mn is an element which has a low phase transition Temperature stabilized. Outside the range of 0.0005-0.0003 By weight, the above-mentioned effect can not be obtained become. If it is added excessively, In particular, it has a bad effect on plating adhesion. Consequently, it is desired the boron content is limited to the range of 0.0005-0.0035% by weight.

Ti, Nb and V: 0.15 weight percent or fewer

titanium (Ti), niobium (Nb) and vanadium (V) are grain refining elements. If overly added, each of these reduces overall profitability. Consequently, it is desired that the content thereof is limited to 0.15% by weight or less.

Subsequently, will the present invention with reference to examples and comparative examples be described in more detail. The following examples are shown to illustrate further various aspects of the present invention, but are not intended to limit the scope of the invention in any aspect.

Examples 1 to 6 and Comparative Examples 1 to 3

steel slabs with the compositions listed in the following Table 1 are were at 1200 ° C heated and then in turn the methods of hot rolling, winding (Rolling up), pickling, cold-rolling and thus pose Steel sheets with a thickness from 1.0 mm ago. Subsequently was a recrystallization annealing process for the Steel sheets under the conditions executed which are listed in Table 2.

The reduction ratio in the last hot rolling step was to 10%, the coiling temperature on 650 ° C, the reduction ratio in the cold rolling step to 65% and the cooling rate after the Rekristallungsglühverfahren to 20 ° C / s set.

The tensile strengths, yield stresses and r values were measured for steel sheets produced by the recrystallization annealing method in Examples 1 to 6 and Comparative Examples 1 to 3. In addition, the (111) // RD orientations and (100) <001> orientations were calculated by volume weight using an EBSD technique. The data are shown in the following Table 2. [Table 1] class Composition (weight percent) C Si Mn P al S sb Not a word B Ti Nb V example 1 Fictitious steel 0,055 0.15 2.1 0,012 0.42 0,003 0,035 0.15 0,002 - - - Example 2 Fictitious steel 0,068 0.13 1.69 0.011 0.95 0.0045 0.045 - 0,002 - - - Example 3 Fictitious steel 0,076 0.04 1.90 0.023 1.2 0,008 0.04 0.08 - - 0.01 - Example 4 Fictitious steel 0.08 0.07 2.0 0.057 1.7 0,007 0.06 0.18 - 0.03 - - Example 5 Fictitious steel 0.08 0.11 1.34 0.01 1.0 0.005 0.05 0.25 0,002 - - - Example 6 Fictitious steel 0.09 0.12 1.56 0.056 0.7 0,003 0.08 0.25 0,002 - - - Comparative Example 1 Compared steel 0.03 0.18 1.42 0,041 0.88 0.001 0,055 0.11 0.001 - 0.01 - Comparative Example 2 Compared steel 0.06 0.18 1.69 0.011 0.94 0.0045 - - 0,002 - - - Comparative Example 3 Compared steel 0.15 0.1 1.54 0,013 1.16 0.009 0.65 0.9 - - 0.01 0.05 [Table 2] class Glühtemp. (° C) Glow time (s) Tensile strength (MPa) Renewal (%) (111) // RD (Vol%) (100) <001> (Vol%) R-value example 1 Fictitious steel 790 60 586 31 0.45 0.1 1.45 Example 2 Fictitious steel 790 60 635 29.4 0.38 0.13 1.33 Example 3 Fictitious steel 790 60 623 30 0,375 0.12 1.31 Example 4 Fictitious steel 820 60 652 28 0.36 0.16 1.3 Example 5 Fictitious steel 820 60 671 27 0.35 0.16 1.3 Example 6 Fictitious steel 820 60 734 26 0.35 0.19 1.28 Comparative Example 1 Compared-it steel 790 60 682 23 0.29 0.23 1.1 Comparative Example 2 Compared-it steel 790 60 630 28 0.34 0.22 1.05 Comparative Example 3 Compared-it steel 850 60 950 18 0.22 0.3 0.75

As shown in Table 2, it was possible high strength steel sheets with high r-values and an excellent Deformability by incorporation of antimony (Sb) in an optimum Produce quantity.

In addition, the 1 and 2 Volume fractions (volume percent) of the (111) // RD orientation and (100) <001> orientation according to the admixture of antimony (Sb) and 3 represents the r values according to the addition of antimony (Sb).

The steel sheets according to the present invention, as in 1 showed the (111) // RD orientation as the orientation distribution of 0.035%. In relation to 2 the alignment density was lowered. In contrast, the orientation density for comparative examples is increased.

In relation to 3 In addition, high r values were obtained when the added amount of antimony is satisfied with the state of the present invention.

As As described above, the present invention can be a high-strength one Dual phase steel sheet for one Hot dip galvanizing, which has a high r-value and excellent Deformability and contraction, by the admixture of Antimony (Sb) in a reasonable range to the alloying elements and methods of hot rolling, coiling, Cold rolling and recrystallization annealing under optimum process conditions.

Especially Is it possible a high-strength dual-phase steel sheet with a high tensile strength to produce with one cycle of cold rolling and annealing and thereby the productivity to increase, reduce manufacturing costs and increase mass production enable.

The present invention has been described in detail with respect to preferred embodiments thereof. However, it will be appreciated by one skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the art The scope of the invention is defined in the appended claims and the equivalents thereof.

Claims (10)

High strength ferrite martensite sheet steel with one excellent deformability and excellent contraction property, which has: 0.05-0.15 weight percent C; 0.15 Weight percent or less Si; 0.5-2.7 weight percent Mn; 0.1-0.7 weight percent al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element consisting of 0.01-0.6 weight percent Mo and 0,0005-0,0035 Weight percent B existing group is selected; and the compensation Fe and identical foreign substances. High strength steel sheet according to claim 1, which also Having: 0.15 weight percent or less of at least an element consisting of the group consisting of Ti, Nb and V. according to a Target tensile strength selected becomes. A high strength steel sheet according to claim 1, wherein said γ-fiber orientation ((111) // RD-orientation) the ferrite matrix is 0.35 volume percent or more and cube orientation ((100) <001>) of the ferrite matrix 0.2 volume percent or less. Method for producing a high-strength steel sheet with an excellent ductility and excellent contraction property, which has the following steps: Delivering a slab, which has: 0.05-0.15 Weight percent C; 0.15 weight percent or less of Si; 0.5-2.7 weight percent Mn; 0.1-0.7 Weight percent Al; 0.005-0.03 Weight percent P; 0.01-0.3 Weight percent Sb; 0.002-0.02 Weight percent S; at least one element consisting of 0.01-0.6 weight percent Mo and 0,0005-0,0035 Weight percent B existing group is selected; and the compensation Fe and identical foreign substances; Reheating the slab at 1050-1250 ° C; hot rolling the slab to a reduction ratio at the last (final) level to be set at 10% or less; Wrap the hot rolled Steel sheet at 600-750 ° C and then Cold rolling the wound steel sheet; and Recrystallization annealing of cold rolled steel sheet and then quenching the recrystallization annealed steel sheet. The method of claim 4, wherein the recrystallization annealing is for 30-180 seconds performed at 750-850 ° C and the quenching is carried out at a speed of 15-2,000 ° C / s. The method of claim 4 wherein 0.15 weight percent or less of at least one element consisting of Ti, Nb and V existing group according to one Nominal tensile strength selected is added to deliver a slab. Method for producing a high-strength steel sheet from a dual phase structure, which has excellent ductility and excellent contraction property even with one cycle cold rolling and annealing comprising the steps of adding an effective amount At Sb, the evolution of cube alignment and twisted cube orientation ((100) <011>) and to increase the development of the (111) // RD alignment. The method of claim 7, wherein the amount of Sb 0.3 weight percent or less. The method of claim 8, wherein the amount of the amount at Sb 0.01-0.3 Weight percent is. Motor vehicle, which is the steel sheet of the claim 1 has.