CN1193110C - Composite structure type hipe tensile strength steel plate, plated plate of composite structure type high tensile strength steel and method for their production - Google Patents

Abstract

The present invention provides a high-strength dual-phase cold rolled steel sheet having an excellent deep drawability, wherein the steel sheet has a composition comprising C: 0.01-0.08 mass %, Si: not more than 2.0 mass %, Mn: not more than 3.0 mass %, P: not more than 0.10 mass %, S: not more than 0.02 mass %, A1: 0.005-0.20 mass %, N: not more than 0.02 mass % and V: 0.01-0.5 mass %, provided that V and C satisfy a relationship of 0.5xC/12<=V/51<=3xC/12, and the remainder being Fe and inevitable impurities, and has a microstructure consisting of a ferrite phase as a primary phase and a secondary phase including martensite phase at an area ratio of not less than 1% to a whole of the microstructure and a high-strength dual-phase galvanized steel sheet comprising a galvanized coating on the above steel sheet as well as a method of producing the same.

Description

High strength dual phase steel sheet and high strength dual phase are electroplated steel sheet and manufacture method thereof

Technical field

The present invention relates to have excellent deep-draw ductile high strength dual phase steel sheet, be particularly related to have 440MPa or bigger tensile strength and be suitable in the used for vehicle steel sheet, using, have excellent deep-draw ductile two-phase Cold Rolled Sheet Steel and have excellent deep-draw ductile high strength dual phase Enplate, and the method for making them.

Background technology

Recently,, need improve the fuel consumption in the vehicles from keeping the viewpoint of global environment, and from the vehicle collision process viewpoint of personal protection, need improve the security of car body.For this reason, make car body not only light but also firm research just energetically.

To make not only light but also firm of car body in order satisfying simultaneously, to it is said that the starting material of highly enriched constituent part are effectively, and recently, high-strength steel sheet is just energetically as the part of the vehicles.

Most of car body parts form as raw-material steel sheet by punch process.For this reason, employed high-strength steel sheet need have excellent punching formation property.In order to improve punching formation property, as the steel-sheet mechanical property, must have high Lankford value (r value), high ductility (E1) and low yielding stress (YS).

Yet usually along with steel sheet is highly enriched, r value and ductility reduce and the punching formation property variation, thereby yielding stress rising simultaneously makes with the mold forming variation, therefore is easy to occur the resilience problem.

And, according to the position of employed vehicle parts, also needing high erosion resistance, the various surface treated steel sheet that therefore will have excellent anticorrosive at present is as the used for vehicle steel sheet.In the middle of these surface-treated steel sheets, Enplate be in identical service line by carrying out recrystallization annealing and galvanized continuous zinc coating device fabrication, therefore excellent erosion resistance and cheap product be provided is possible.And, except the erosion resistance of excellence, heat-treat the alloy Enplate that obtains by after zinc-plated, also very excellent aspect weldability and punching formation property.Therefore, they are widely used.

In order further to impel not only light but also firm of car body, except exploitation has the high strength cold-rolled steel sheet of excellent punching formation property, also need to develop the high strength Enplate that has excellent anticorrosive by the continuous zinc coating service line.

As the exemplary of high-strength steel sheet, should be mentioned that to have soft ferritic phase and the hard microstructural two-phase steel sheet of martensitic phase two-phase with good punching formation property.Particularly the two-phase steel sheet yielding stress made from the gas jet cooling after continuous annealing is low, and has high ductility and excellent baking hardening capacity.Above-mentioned two-phase steel sheet has good workability usually, but the defective that has is: the workability under the mal-condition is poor, and particularly the r value is low and deep-draw ductility is poor.

And zinc-plated so that excellent anticorrosive to be provided when carrying out, the continuous zinc coating service line generally will assemble annealing device and electroplating device continuously., carrying out under the galvanized situation, the cooling after the annealing is subjected to the restriction of electroplating temperature for this reason, and can not just be reduced to the temperature that is lower than electroplating temperature at once, causes cooling to be interrupted.As a result, average rate of cooling must diminish.Therefore, when in the continuous zinc coating service line, making Enplate, in the steel sheet after zinc-plated, be difficult to be formed on the martensitic phase that produces under the cooling conditions of big rate of cooling.So, be difficult to manufacturing usually by the continuous zinc coating service line and have ferritic phase and the microstructural high strength Enplate of martensitic phase two-phase.

Under this disadvantageous condition, attempt to increase two-phase steel-sheet r-value to improve deep-draw ductility.For example, JP-B-55-10650 discloses a kind of method, and this method is, after cold rolling, from the recrystallization temperature to A _C3Carry out pack annealing in the temperature range of transition point, after this, be heated to the continuous annealing that comprises quenching and tempering after 700-800 ℃, to obtain to mix microstructure.Yet, in this method, owing to during continuous annealing, carry out quenching and tempering, so high yield stress, can not obtain low yield ratio thus.Steel sheet with so high yielding stress is unsuitable for impact briquetting, and its defective is: punching parts bad with mold forming.

A kind of method that reduces high yielding stress is also disclosed in JP-A-55-100934.In this method, at first carry out pack annealing to obtain high r-value, wherein make the temperature of pack annealing arrive the two-phase region of ferrite (α)-austenite (γ), and between soaking period, manganese is enriched to the γ phase mutually from α.Along with the manganese of enrichment during continuous annealing preferentially becomes the γ phase mutually, even the rate of cooling in the gas jet cooling also can obtain the two-phase microstructure, and the further step-down of yielding stress.Yet, in this method, because α-long-time enrichment manganese in γ two-phase region, need under high relatively temperature, carry out pack annealing, therefore in production stage, there are many problems, for example, tempering color occurs, reduce the work-ing life of the inner cover that is used for body of heater etc. by often occurring adhesion between the steel sheet of the coiled material inside that causes of thermal expansion in the annealing.Therefore, up to now, industrial be difficult to stably make have high r-value and hang down the high-strength steel sheet of yielding stress.

In addition, JP-B-1-35900 discloses a kind of method, wherein (composition is: 0.012 weight % carbon-0.32 weight % silicon-0.53 weight % manganese-0.03 weight % phosphorus-0.051 weight % titanium) by cold rolling a kind of steel, be heated to 870 ℃ corresponding to α-γ two-phase region, and cool off with the average rate of cooling of 100 ℃/s subsequently, can make the two-phase Cold Rolled Sheet Steel that has very high r-value and hang down yielding stress, r-value=1.61, YS=224MPa and TS=482MPa.Yet, after cold rolling, the high rate of cooling that is difficult to obtain 100 ℃/s in the gas injection cooling of in continuous annealing service line or continuous zinc coating service line, generally using, this need use water quenching equipment, and problem becomes actual in the surface treatment of water quenching steel-sheet, therefore has problems in production unit and material.

In addition, attempt to make the high strength dual phase Enplate.In the past, the method as making the high strength dual phase Enplate typically uses a kind of like this method, wherein by use add be used to improve hardening capacity in a large number be convenient to form the low-temperature transformation phase such as chromium or the such alloying element of molybdenum.Yet, add a large amount of alloying elements and can cause undesirable production cost to increase.

And, as disclosed among the JP-B-62-40405 etc., advise a kind of like this method, make the high strength dual phase Enplate by the rate of cooling that limits after electroplating in annealing back or the continuous zinc coating service line.Yet because the equipment that is used for the continuous zinc coating service line is limited, this method is unactual, and, it is said that the steel sheet that obtains in this way has inadequate ductility.

Of the present invention open

Therefore, an object of the present invention is to address the above problem and provide to have excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel and have excellent deep-draw ductile high strength dual phase Enplate and their manufacture method.

And, term used herein " Enplate " comprising: by electroplating Enplate acquisition, that also contain aluminium etc. outside dezincifying and electroplating the back and handle the iron of horse Trix ultrahigh-strength thin steel sheet is diffused into the alloy Enplate that obtains in the electrolytic coating by carrying out heat (alloying).

In order to achieve the above object, the contriver has carried out many researchs to alloying element to the influence of microstructure in the steel sheet and recrystallization texture.Found that, before recrystallization annealing, by the carbon in the steel ingot is restricted to lower aq and make content of vanadium and carbon content proportional, carbon in the steel is separated out with the form of vanadium carbide, thereby reduce solid solution C as much as possible, thereby form { 111} recrystallization texture, to obtain high r-value, subsequently by being heated to α-γ two-phase region dissolving vanadium carbide, with enrichment carbon in austenite, in process of cooling subsequently, easily generate martensite, can stably make thus and have high r-value and excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel and high strength dual phase Enplate.

To set forth the result of the basic experiment that the contriver does below.

In this case, the high strength dual phase Cold Rolled Sheet Steel of TS:590MPa grade and the high strength dual phase Cold Rolled Sheet Steel of TS:780MPa grade are experimentized.

High strength dual phase Cold Rolled Sheet Steel to the TS:590MPa grade under the condition at first, below carries out fundamental test.The steel disc that each is different (has following basal component: carbon: 0.03 weight %, silicon: 0.02 weight %, manganese: 1.7 weight %, phosphorus: 0.01 weight %, sulphur: 0.005 weight %, aluminium: 0.04 weight %, nitrogen: the content of vanadium that 0.002 weight % and 0.03-0.55 weight % do not wait) all be heated to 1250 ℃ and soaking, carrying out three passages rolling (three-pass rolling) then under 900 ℃ finishing mill delivery temperature is 4.0 millimeters hot rolled steel sheet to obtain thickness.

In addition, carry out processing same as described above for various steel discs with following basal component, carbon: 0.03 weight %, silicon: 0.02 weight %, manganese: 1.7 weight %, phosphorus: 0.01 weight %, sulphur: 0.005 weight %, aluminium: 0.04 weight % and nitrogen: 0.002 weight % and by adding 0.03-0.04 weight % respectively, 0.01-0.18 the vanadium of weight % and 0.01-0.18 weight %, niobium and titanium and have (2 * Nb[weight %]/93+2 * Ti[weight %]/48)/different value of (V[weight %]/51), to satisfy 0.5 * C[weight %]/12≤(V[weight %]/51+2 * Nb[weight %]/93+2 * Ti[weight %]/48)≤3 * C[weight %]/12 relation.

And the hot rolled steel sheet after the finish rolling is the same with web process, and the insulation of carrying out 650 ℃ * 1 hour is handled.Subsequently, the rolling rate of compression with 70% is carried out cold rolling to steel sheet, is 1.2 millimeters Cold Rolled Sheet Steel with acquisition thickness.Then, Cold Rolled Sheet Steel carried out recrystallization annealing 60 seconds and cooled off with the rate of cooling of 30 ℃/s under 850 ℃.

On the other hand, the high strength dual phase Cold Rolled Sheet Steel that carries out the TS:780MPa grade under the condition below carries out fundamental test.

Various steel discs, its basal component is carbon: 0.04 weight %, silicon: 0.70 weight %, manganese: 2.6 weight %, phosphorus: 0.04 weight %, sulphur: 0.005 weight %, aluminium: 0.04 weight % and nitrogen: 0.002 weight % and by adding 0.02-0.06 weight % respectively, 0.01-0.12 the vanadium of weight % and 0.01-0.12 weight %, niobium and titanium and have (the different value of 2 * Nb/93+2 * Ti/48)/(V/51), to satisfy 0.5 * C[weight %]/12≤(V[weight %]/51+2 * Nb[weight %]/93+2 * Ti[weight %]/48)≤3 * C[weight %]/12 relation, these various steel discs are heated to 1250 ℃ and soaking, it is rolling to carry out three mill traines then under 900 ℃ finishing mill delivery temperature, is the hot rolled steel sheet of 4.0mm to obtain thickness.And the hot rolled steel sheet after the finish rolling is the same with web process, and the insulation degree that carried out 650 ℃ * 1 hour is handled.Subsequently, the rolling rate of compression with 70% is carried out cold rolling to steel sheet, is 1.2 millimeters Cold Rolled Sheet Steel with acquisition thickness.Then, Cold Rolled Sheet Steel is carried out recrystallization annealing 60 seconds under 850 ℃, and cool off with the rate of cooling of 30 ℃/s.

Cold Rolled Sheet Steel for such acquisition carries out tension test, with the research tensile properties.Use JIS No.5 tensile test specimen to carry out tension test.The r-value is defined as rolling direction (r _L), with respect to the tilt directions (rD) of 45 degree and of rolling direction perpendicular to the direction (r of (90 °) rolling direction _C) average r-value {=(r _L+ r _C+ 2 * r _D)/4}.

Fig. 1 a and 1b explanation use contain vanadium but do not contain niobium and the Cold Rolled Sheet Steel of the TS:590MPa grade that the steel ingot of titanium, vanadium is made in, the content of vanadium in the steel ingot is to the influence of the r-value and the yield ratio (YR=yielding stress (YS)/tensile strength (TS) * 100 (%)) of Cold Rolled Sheet Steel.And the X-coordinate among Fig. 1 a and the 1b is the atomic ratio ((V/51)/(C/12)) of content of vanadium and carbon content, and among Fig. 1 a, ordinate is the r-value, and among Fig. 1 b, ordinate is yield ratio (YR).

The same as what from Fig. 1 a and 1b, seen, be restricted to 0.5-3.0 by atomic ratio with content of vanadium in the steel ingot and carbon content, can obtain high r-value and low yield ratio, and might make and have excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel.

In steel sheet of the present invention, the contriver finds: because solid solution carbon and nitrogen are less, and formed in a large number before recrystallization annealing that { the 111} recrystallization texture is so can obtain high r-value.The contriver also finds: by dissolving vanadium carbide in α-γ two-phase region annealing, and solid solution carbon be enriched in a large number austenite mutually in, austenite can easily be transformed into martensite in process of cooling subsequently, thereby obtains ferrite and martensitic two-phase microstructure.

Although mainly as carbide forming element, the contriver notices: with regard to obtain solid solution carbon effectively by annealing at higher warm area for, vanadium has higher carbide solubleness than titanium and niobium for past titanium and niobium.That is, find: because when at high temperature annealing, vanadium carbide is compared easier dissolving with titanium carbide with niobium carbide, so by can obtain in α-γ two-phase region annealing q.s be used for austenitic transformation is become martensitic solid solution carbon.In addition, clearly, add vanadium and can form this phenomenon the most significantly, but adding niobium together also can obtain similar result with titanium.

The present invention is based on above-mentioned knowledge, can realize another invention and obtain following knowledge.

The contriver has compared by the r-value in the high strength dual phase Cold Rolled Sheet Steel of the TS:590MPa grade of using the steel ingot manufacturing that also contains niobium and titanium except containing vanadium and TS:780MPa and has illustrated as follows.Fig. 2 a and 2b explanation: contain in the Cold Rolled Sheet Steel of TS:590MPa grade that the steel ingot of vanadium, niobium and titanium makes and TS:780MPa grade in use, the content of vanadium, niobium and titanium is to the tensile strength (TS) of Cold Rolled Sheet Steel and the influence of Lankford value (r-value) in the steel ingot.And the X-coordinate among Fig. 2 a and the 2b is that (2 * Nb/93+2 * Ti/48)/(V/51), ordinate is tensile strength (TS) among Fig. 2 a, and ordinate is the r-value among Fig. 2 b for the atomic ratio of niobium and titanium content and content of vanadium.

According to The above results, in the TS:780MPa grade, attempt to carry out highly enriched by a large amount of solution strengthening elements, so that compare, make the r-value lower by increasing dissolved carbon content etc. with the TS:590Mpa grade.Yet, in the TS:780MPa grade, when (when the value of 2 * Nb/93+2 * Ti/48)/(V/51) was not less than 1.5, the r-value obviously improved.When (value of 2 * Nb/93+2 * Ti/48)/(V/51) significantly improves the r-value when being not less than 1.5, this feature in the TS:780MPa grade is found in the TS:590MPa grade.

Although cause the details of The above results not clear, but it is believed that, as in the TS:780MPa grade, in the system that contains the element that causes reducing the r-value in a large number such as solid solution carbon etc., compare with vanadium, the easier form with compound of niobium and titanium is separated out solid solution carbon and nitrogen, and the content of solid solution carbon and nitrogen reduces after hot rolling, thereby has improved the r-value.And, when (when the value of 2 * Nb/93+2 * Ti/48)/(V/51) surpassed 15, TS significantly descended, and this is unfavorable for obtaining the high strength dual phase Cold Rolled Sheet Steel of TS:780MPa grade.This is considered to because the following fact: compare with vanadium carbide, niobium carbide and titanium carbide dissolve hardly, if the add-on of niobium and titanium content is greater than the add-on of content of vanadium, then in α-γ two-phase region annealing, the austenite carbon content of middle enrichment mutually greatly reduces, and the martensitic phase that the cooling back forms is a remollescent.

Based on above-mentioned knowledge, realize the present invention by further check.The present invention is summarized as follows.

(1) a kind of have an excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, it is characterized in that the steel-sheet composition comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is that vanadium and carbon satisfy the relation by following formula (i) expression:

0.5 remaining is iron and unavoidable impurities for * C/12≤V/51≤3 * C/12 (i), it has by as the ferritic phase of primary phase with comprise and the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase.

(2) a kind of according to the excellent deep-draw ductile of (1) have high strength dual phase Cold Rolled Sheet Steel, wherein the steel-sheet composition further comprises niobium: greater than 0 weight % but be not more than 0.3 weight %, and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, and condition is that vanadium, niobium, titanium and carbon satisfy by following formula (ii) rather than the relation of formula (i) expression:

0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48)≤(ii) remaining is iron and unavoidable impurities to 3 * C/12.

And niobium preferably: 0.001-0.3 weight % and titanium: a kind of among the 0.001-0.3 weight % or two kinds amount to and are no more than 0.3 weight %.

(3) a kind of according to the excellent deep-draw ductility of (2) have high strength dual phase Cold Rolled Sheet Steel, wherein steel sheet comprises carbon: 0.03-0.08 weight %, silicon: 0.1-2.0 weight %, manganese: 1.0-3.0 weight %, phosphorus: be no more than 0.05 weight % and S: be no more than 0.01 weight %, and vanadium, niobium and titanium satisfy 1.5≤(relation of 2 * Nb/93+2 * Ti/48)/(V/51)≤15.

(4) a kind of according to (1) in (3) any one have an excellent deep-draw ductility high strength dual phase Cold Rolled Sheet Steel, wherein steel sheet further comprises in organizing one group or two groups of following A group and B:

A group: a kind of in chromium and the molybdenum or two kinds amount to and are no more than 2.0 weight %;

B group: a kind of in the copper and mickel or two kinds amount to and are no more than 2.0 weight %.

(5) a kind of manufacturing has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, and it comprises hot-rolled steel ingot, and pickling is cold rolling, then at A _C1Transition point is to A _C3The temperature range of transition point is carried out continuous annealing, described steel ingot comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is that vanadium and carbon satisfy the relation of (iii) being represented by following formula:

0.5 (iii) remaining is iron and unavoidable impurities to * C/12≤V/51≤3 * C/12.

(6) a kind of manufacturing according to (5) has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, wherein the steel-sheet composition further comprises niobium: greater than 0 weight % but be not more than 0.3 weight % and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, and condition is that vanadium, niobium, titanium and carbon satisfy by following formula (iv) rather than the relation (iii) represented of formula:

0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48)≤(iv) remaining is iron and unavoidable impurities to 3 * C/12.

And niobium preferably: 0.001-0.3 weight % and titanium: one or both of 0.001-0.3 weight % amount to and are no more than 0.3 weight %.

(7) a kind of manufacturing according to (6) has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, wherein steel ingot comprises carbon: 0.03-0.08 weight %, silicon: 0.1-2.0 weight %, manganese: 1.0-3.0 weight %, phosphorus: be no more than 0.05 weight % and sulphur: be no more than 0.01 weight %, and vanadium, niobium and titanium satisfy 1.5≤(relation of 2 * Nb/93+2 * Ti/48)/(V/51)≤15.

(8) a kind of have the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel according to any one manufacturing in (5)-(7), and wherein steel ingot further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

(9) a kind of have an excellent deep-draw ductile high strength dual phase Enplate, and it is included in (1)-(4) the zinc coating on the disclosed steel sheet in any one.

(10) a kind of manufacturing has the method for excellent deep-draw ductile high strength dual phase Enplate, wherein after continuous annealing, at A _C1Transition point is to A _C3In the temperature range of transition point, carry out zinc-plated according to the manufacture method of describing in (5)-(7) any one.

(11) a kind of have the method for excellent deep-draw ductile high strength dual phase Enplate according to (10) manufacturing, wherein further is included in from A _C1Transition point is to A _C3In the temperature range of transition point, the continuous annealing step between cold rolling step and continuous annealing step.

(12) a kind of basis (10)-(11) are made and are had the method for excellent deep-draw ductile high strength dual phase Enplate, and wherein steel ingot further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

Cold Rolled Sheet Steel of the present invention and Enplate are that tensile strength (TS) is not less than 440Mpa and has excellent deep-draw ductile high strength dual phase steel sheet.

At first, the reason with the composition in restriction Cold Rolled Sheet Steel of the present invention and the Enplate is explained as follows.And weight % is expressed as " % " simply.

Carbon: 0.01-0.08%

Carbon is to be used to increase steel-sheet intensity and further to promote form ferrite and the microstructural element of martensitic two-phase, from forming the microstructural viewpoint of two-phase in the present invention, must contain and be no less than 0.01%, preferably is no less than 0.015% carbon.And TS is not less than 540MPa and TS is not less than 780MPa if plan intensity increased to, and preferably carbon content is no less than 0.015% and be no less than 0.03% respectively.On the other hand, when carbon content surpasses 0.08%, can hinder the formation of 111} recrystallization texture, thereby deep-draw ductility is worsened.Gu this, the present invention is restricted to 0.01-0.08% with carbon content.When special when need increasing steel-sheet intensity, 0.03-0.08% preferably.And, from deep-draw ductile viewpoint, preferably be no more than 0.05%.

Silicon: be no more than 2.0%

Although silicon is can increase steel sheet intensity and the useful strengthening element that significantly do not reduce steel sheet ductility,, can causes that not only deep-draw ductility worsens, and surface property is worsened if content surpasses 2.0%.Therefore, silicon is restricted to is no more than 2.0%.And, be not less than 780MPa if plan that intensity is increased to TS, preferably be no less than 0.1% to guarantee required intensity.And preferably be no less than 0.01% and be not less than 440Mpa so that intensity is increased to TS, this is a main purpose of the present invention.

Manganese: be no more than 3.0%

Manganese has the effect of strengthening steel, further also has the critical cooling rate of reducing to obtain (obtention) ferrite and martensitic two-phase microstructure, thereby promote the effect that ferrite and martensite two-phase microstructure form, therefore preferably comprise content according to the rate of cooling after the annealing.And manganese still prevents because sulphur forms the effective element of fire crack, therefore preferably suitably determines content according to sulphur content.Yet, when manganese content surpasses 3.0%, deep-draw ductility and weldability are worsened.Therefore, in the present invention, manganese content is restricted to is no more than 3.0%.And in order significantly to bring into play above-mentioned effect, preferably manganese content is no less than 0.5%, is not less than 780MPa for intensity is increased to TS, particularly preferably is to be no less than 1.0%.And, for being increased to TS, intensity is not less than 440MPa, preferably be not less than 0.1%, and this is a main purpose of the present invention.

Phosphorus: be no more than 0.10%

Phosphorus has the effect of strengthening steel, can determine required phosphorus amount according to desirable strength.When phosphorus content surpasses 0.10%, can reduce punching formation property.Therefore, phosphorus content is restricted to is no more than 0.10%.And, more excellent if desired punching formation property, preferably phosphorus content is no more than 0.08%.And, when containing a large amount of carbon, manganese etc. in order to guarantee TS to be not less than 780MPa, reduce in order to prevent weldability, preferably phosphorus content is no more than 0.05%.In addition, be not less than 440MPa, preferably be no less than 0.001% if plan that intensity is increased to TS.

Sulphur: be no more than 0.02%

Sulphur exists as impurity in steel sheet, and sulphur is to cause steel-sheet ductility and formability, particularly make the element of crimping (stretch-flanging) mis-behave outward.Therefore, preferably reduce as much as possible, when it being reduced to when being no more than 0.02%, sulphur does not produce bad influence, and therefore in the present invention, S content is the upper limit with 0.02%.And, when the more excellent stretching, extension of needs-flanging performance, or when containing a large amount of carbon, manganese etc. in order to guarantee TS to be not less than 780MPa, You Yi weldability if desired, sulphur content preferably is no more than 0.01%, more preferably is no more than 0.005%.On the other hand, consider the cost of removing sulphur in the steelmaking process, sulphur content preferably is no less than 0.0001%.

Aluminium: 0.005-0.20%

Aluminium adds in the steel as deoxidant element, and aluminium is the useful element that improves the cleanliness factor of steel, but less than 0.005% o'clock, can not obtain additive effect.On the other hand, when it surpasses 0.20%, can not obtain bigger desoxydatoin, deep-draw ductility is worsened.Therefore, aluminium content is restricted to 0.005-0.20%.And the present invention does not repel the method for making steel that is undertaken by the desoxydatoin beyond the aluminium deoxidation.For example, can carry out titanium deoxidation or silicon deoxidation.Steel sheet with these method of deoxidation manufacturings is also included within the scope of the present invention.In this case,, do not hinder steel-sheet characteristic of the present invention yet, therefore comprise that the steel sheet of calcium, REM etc. is also included within the scope of the present invention naturally even in molten steel, add calcium, REM etc.

Nitrogen: be no more than 0.02%

Nitrogen is the element that increases steel sheet intensity by solution hardening and strain aging sclerosis, but when nitrogen content surpassed 0.02%, nitride increased in the steel sheet, thereby steel-sheet deep-draw ductility is obviously worsened.Therefore, nitrogen content is restricted to is no more than 0.02%.And, needing punching formation property to have under the situation of bigger improvement, nitrogen content preferably is no more than 0.01%, more preferably is no more than 0.004%.In this case, consider the cost of denitrogenation in the steelmaking process, preferably nitrogen content is no less than 0.0001%.

Vanadium: 0.01-0.5% and 0.5 * C/12≤V/51≤3 * C/12

In the present invention, vanadium is a kind of most important element.Before recrystallize, solid solution C separates out with the form of vanadium carbide and is fixing, thereby form the 111} recrystallization texture, thereby can obtain high r-value.And, in α-γ two-phase region annealing, vanadium dissolving vanadium carbide and austenite mutually in a large amount of solid solution carbon of enrichment, in process of cooling subsequently, austenite is transformed into martensite mutually easily, thereby can obtain to have ferrite and the microstructural two-phase steel sheet of martensite two-phase.When content of vanadium is no less than 0.01%, more preferably be no less than 0.02%, and when satisfying 0.5 * C/12≤V/51 with the relation of carbon content, it is remarkable that this effect becomes.On the other hand, when content of vanadium surpasses 0.5% or when the pass with carbon content was V/51＞3 * C/12, the vanadium carbide that is positioned at α-γ two-phase region dissolved hardly, and almost can not get ferrite and martensitic two-phase microstructure.Therefore, content of vanadium is restricted to 0.01-0.5% and 0.5 * C/12≤V/51≤3 * C/12.And in order to obtain ferrite and martensite two-phase microstructure, V/51≤2 * C/12 is preferred.

Except that mentioned component, more preferably comprise niobium: greater than 0% but be no more than 0.3 (weight) % and Ti: greater than 0% but be no more than in 0.3% one or both, total is no more than 0.3 (weight) %, and the satisfied 0.5 * C/12 of the relation of vanadium, niobium, titanium content and carbon content≤(V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12 rather than vanadium and the satisfied 0.5 * C/12 of carbon content≤V/51≤3 * C/12.

Niobium: greater than 0% but be not more than 0.3% and Ti: greater than 0% but one or both totals that are not more than in 0.3% are not more than 0.3%, and vanadium, niobium, titanium and carbon satisfy 0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12

Niobium is the same with vanadium with titanium to be carbide forming element, and has the effect identical with above-mentioned vanadium.That is to say, by before recrystallize, separating out and fixing solid solution carbon with the form of niobium carbide and titanium carbide, thereby form { 111} recrystallization texture, can obtain high r-value, and by dissolving niobium carbide and titanium carbide in α-γ two-phase region annealing, austenite mutually in a large amount of solid solution carbon of enrichment and in process of cooling subsequently, be transformed into martensite, can obtain to have the microstructural two-phase steel sheet of ferrite and martensite two-phase.And, quite little because the effect of above-mentioned niobium and titanium is compared with the effect of vanadium, so when not adding vanadium, can not fully improve the deep-draw ductility of target of the present invention when only in steel ingot, adding niobium and titanium.

Therefore, preferably add niobium and titanium greater than 0%.More preferably each content of niobium and titanium all is no less than 0.001%.In this case, in order to produce above-mentioned effect, preferably satisfy 0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48) with the relation of carbon and content of vanadium.On the other hand, when niobium and titanium each content or they are when totalling over 0.3%, perhaps satisfy (during V/51+2 * Nb/93+2 * Ti/48)＞3 * C/12 when the relation of niobium and titanium content and carbon and content of vanadium, in α-γ two-phase region the dissolving of carbide taking place hardly, therefore almost can not obtain ferrite and martensitic two-phase microstructure.Therefore, preferably during a kind of in only adding niobium or titanium, each of content of niobium and titanium content is all greater than 0% but be not more than in 0.3% the scope, when adding niobium and titanium together, niobium and titanium content amount to and are not more than 0.3% and satisfy 0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12 with the relation of vanadium and carbon content.

On the other hand, be not less than 780MPa if plan that intensity is increased to TS, add a large amount of solid solutions and strengthen element, for example carbon, manganese etc. are easy to make deep-draw ductility to worsen.In this case, vanadium, niobium and titanium content are better is 1.5≤(2 * Nb/93+2 * Ti/48)/(V/51)≤15.Will (2 * Nb/93+2 * Ti/48)/(V/51) be restricted to be not less than 1.5 reason due to: though the details of reason is not clear, but compare with vanadium, by adding a large amount of niobiums and titanium, reduce solid solution thereby can promote hot rolling to form carbide afterwards, therefore form { 111} recrystallization texture easily.And, in order to ensure the intensity that TS is not less than 780MPa, wish (2 * Nb/93+2 * Ti/48)/(V/51) be not more than 15.

And, except that above-mentioned composition of steel, preferably, further comprise in organizing one group or two groups of following A-group and B-according to steel of the present invention:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0%;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0%.

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0%

For ferrite and martensitic two-phase microstructure are provided, the chromium in the A-group is the same with manganese with molybdenum all to have the reduction critical cooling rate to promote the effect of ferrite and martensitic two-phase microstructure formation, if necessary also can comprise them.In order to obtain above-mentioned effect, the following chromium that is limited to of chromium content and molybdenum content: 0.05%, manganese: 0.05%.Yet when in chromium and the molybdenum one or both totalled over 2.0%, deep-draw ductility worsened.For this reason, preferably the chromium in the A-group and in the molybdenum one or both are restricted to amount to and are not more than 2.0%.

The B-group: one or both in the copper and mickel amount to and are no more than 2.0%

Copper and mickel in the B-group has the effect of strengthening steel, and can contain the aequum of with good grounds desirable strength.Yet,, be easy to make deep-draw ductility to worsen when the content of the copper and mickel that adds separately or when totalling over 2.0%.For this reason, one or both in the copper and mickel preferably amount to and are not more than 2.0%.And in order to obtain above-mentioned effect, the lower limit of copper and mickel is respectively a copper: 0.05% and nickel: 0.05%.

In the present invention the element except that above-mentioned element is not particularly limited, even comprise that the interior boron of ordinary steel composition range, calcium, zirconium, REM etc. are also no problem.

In this case, boron is the element with the hardening capacity effect that improves steel, if necessary, also can comprise boron.Yet when boron content surpassed 0.003%, above-mentioned effect was saturated, so boron content preferably is not more than 0.003%.And better scope is 0.001-0.002%.Calcium and REM have the effect that the control sulfide impurities forms, and also have the effect that improves extension-flanging character.When one or both in being selected from calcium and REM totalled over 0.01%, this effect was saturated.For this reason, the content of one or both among calcium and the REM preferably amounts to and is not more than 0.01%.And preferred scope is 0.001-0.005%.

Except above-mentioned element, remaining is iron and unavoidable impurities.The unavoidable impurities of being mentioned is for example antimony, tin, zinc, cobalt etc.The acceptable scope of its content is an antimony: be not more than 0.01%, tin: be not more than 0.1%, zinc: be not more than 0.01% and cobalt: be not more than 0.1%.

Then, will set forth steel-sheet microstructure of the present invention.

Cold Rolled Sheet Steel of the present invention has by as the ferritic phase of primary phase with comprise with respect to the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase.

Have low yielding stress (YS) in order to provide, high ductibility (E1) and excellent deep-draw ductile Cold Rolled Sheet Steel, steel-sheet microstructure of the present invention is become by as the ferritic phase of primary phase with comprise the two-phase microstructure of the secondary phase composite of martensitic phase.Preferably the area ratio as the ferritic phase of primary phase is not less than 80%, because of this time looks is not more than 20%.When the area of ferritic phase than less than 80% the time, be difficult to guarantee high ductibility, and punching formation property is tending towards also descending.And when the needs good ductility, preferably the area of ferritic phase ratio is not less than 85%, because of this time looks is not more than 15%.And, in order to utilize the microstructural advantage of two-phase, need ferritic phase to be not more than 99%.

In the present invention, require time looks to comprise with respect to whole microstructural area than the martensitic phase that is not less than 1%.When martensitic area than less than 1% the time, can not satisfy low yielding stress (YS) and high ductility (E1) simultaneously.More preferably the area of martensitic phase ratio is not less than 3% but be not more than 20%.Under the situation of the good ductility of needs, preferably the area of martensitic phase ratio is not more than 15%.And, inferior looks may only be made up of than the martensitic phase that is not less than 1% area, or by area than be not less than 1% martensitic phase with as the perlite of additional phase mutually, bainite mutually and any composition the in the mixed phase of residual austenite, this does not do special restriction.In a kind of in the back situation, in order more effectively to bring into play the effect of martensitic phase, preferably the area of perlite phase, bainite phase and residual austenite is not more than 50% than amounting to respect to inferior looks microstructure.

Having above-mentioned microstructural Cold Rolled Sheet Steel and Enplate is to have low-stress, high ductibility and excellent deep-draw ductile steel sheet.

Below, will set forth the method for making Cold Rolled Sheet Steel of the present invention and Enplate.

The composition of the steel ingot that uses in the production method of the present invention is identical with the composition of above-mentioned Cold Rolled Sheet Steel and Enplate, so be omitted for the explanation of steel ingot restriction reason.

Cold Rolled Sheet Steel of the present invention is to make like this, uses the steel ingot with above-mentioned scope composition as starting material, and in succession these starting material are carried out following steps: hot rolling obtains the hot-rolled step of hot rolled steel sheet; The acid pickling step of pickling hot rolled steel sheet; Hot rolled steel sheet is carried out the cold rolling step of cold rolling acquisition Cold Rolled Sheet Steel; With Cold Rolled Sheet Steel is carried out recrystallization annealing and obtains cold rolled annealed steel-sheet recrystallization annealing step.

And Enplate of the present invention can also be made like this, uses the steel ingot with above-mentioned scope composition as starting material, and in succession these starting material are carried out following steps: hot rolling is to obtain the hot-rolled step of hot rolled steel sheet; The acid pickling step of this hot rolled steel sheet of pickling; Hot rolled steel sheet is carried out the cold rolling step of cold rolling acquisition Cold Rolled Sheet Steel; With the continuous zinc coating step of Cold Rolled Sheet Steel being carried out recrystallization annealing and zinc-plated acquisition Enplate.And, if necessary, can by before the continuous zinc coating step to Cold Rolled Sheet Steel anneal and acid pickling step make Enplate.

For fear of the macrosegregation of forming,, but also can make employed steel ingot by ingot casting method or thin plate teeming practice preferably by the employed steel ingot of continuous casting manufactured.And, except after making steel ingot and reheat, just being cooled to the ordinary method of room temperature, also can use method for saving energy and without a doubt, for example hot steel ingot is inserted process furnace and refrigerative method not, directly send to rolling a little after the insulation or directly rolling immediately method etc. after the insulation a little.

Above-mentioned starting material (steel ingot) are formed the hot-rolled step of hot rolled steel sheet by heating and hot rolling.In hot-rolled step, as long as can make hot rolled steel sheet, even use the common rolling condition problem that also has nothing special with desired thickness.And the preferred hot-rolled condition of below touching upon is for reference.

Ingot Heating temperature: be not less than 900 ℃

For { the 1111} recrystallization texture improves deep-draw ductility, wishes the ingot Heating temperature is reduced as much as possible to form by making the precipitate alligatoring.Yet when the ingot Heating temperature was lower than 900 ℃, rolling load increased, and bothersome dangerous increase in hot rolling.For this reason, the ingot Heating temperature preferably is not less than 900 ℃.And owing to follow the increase of oxide weight, oxide skin (scale) loss increases, and causes productive rate to descend more preferably 1300 ℃ of the upper limits of ingot Heating temperature.And, produce the viewpoint that bothers the hot rolling from reducing the ingot Heating temperature and preventing, using the stalloy well heater of so-called heating stalloy in hot rolling is effective means, this is self-evident.

Finishing mill delivery temperature: be not less than 700 ℃

In order to obtain uniform hot rolling motherboard microstructure so that excellent deep-draw ductility to be provided after cold rolling and recrystallization annealing, preferably finishing mill delivery temperature (FDT) is not less than 700 ℃.That is to say that when the finish rolling texturing temperature was lower than 700 ℃, not only the microstructure of hot rolling motherboard became inhomogeneous, and the rolling load in the hot rolling becomes higher, and bothersome danger has increased also in hot rolling.

Coiling temperature: be not higher than 800 ℃

The coiling temperature preferably is not higher than 800 ℃.That is, when the coiling temperature surpassed 800 ℃, oxide skin increased, and owing to the loss of oxide skin causes productive rate to descend.And when the coiling temperature was lower than 200 ℃, the steel-sheet shape was obviously bad, and caused that in actual applications the danger of problem increases, so more preferably 200 ℃ of the lower limits of coiling temperature.

As mentioned above, in hot-rolled step of the present invention, preferably steel ingot is heated to more than 900 ℃, carries out hot rolling being not less than under 700 ℃ the finish rolling texturing temperature, and reel not being higher than under 800 ℃ the coiling temperature.

And, in hot-rolled step of the present invention,, can between a part of finish rolling or its passage, be lubricated rolling in order to reduce the rolling load in the hot rolling.In addition, from the viewpoint that steel sheet shape homogenizing and material are homogenized, it is effective using lubrication and rolling.And the frictional coefficient in the lubrication and rolling is 0.10-0.25 preferably.

More preferably continuous rolling processing of hot-rolled step, the lath before and after wherein being positioned at is connected with each other, and is subjected to finish rolling continuously.The viewpoint of run stability from hot rolling, using continuous rolling processing is ideal.

Then, hot rolled steel sheet is carried out pickling to remove oxide skin.It is just enough to carry out acid pickling step according to usual manner, preferably uses such treatment soln such as for example hydrochloric acid, sulfuric acid etc. as Acidwash solution.

And, by hot rolled steel sheet being carried out cold rolling formation Cold Rolled Sheet Steel.Cold rolling condition is had no particular limits, as long as can obtain to have the Cold Rolled Sheet Steel of required sizes and shape, but the rolling rate of compression in preferably cold rolling is not less than 40%.When rolling rate of compression less than 40% the time, can not form { 111} recrystallization texture, and can not obtain excellent deep-draw ductility.

In recrystallization annealing step subsequently, Cold Rolled Sheet Steel of the present invention is carried out recrystallization annealing, to obtain cold rolled annealed steel sheet.In the continuous annealing service line, carry out recrystallization annealing.On the other hand, after cold rolling, by Cold Rolled Sheet Steel being carried out recrystallization annealing and in the continuous zinc coating service line, carrying out zinc-plated manufacturing Enplate of the present invention.In this case, requiring annealing temperature in the recrystallization annealing is (under the two-phase region of α+γ), from A _C1Transition point is to A _C3Carry out in the temperature range of transformation point.The fact that this is so due to, (α+γ) anneals the two-phase region with the carbide of dissolving vanadium, titanium and niobium, thus to austenite mutually in an amount of being enough to of distribution austenitic transformation is become martensitic carbon.When annealing temperature is lower than A _C1During transition point, it is single-phase and can not produce martensite that microstructure becomes ferrite, and be higher than A when annealing temperature _C3During transition point, grain coarsening, microstructure becomes austenite one phase and can not form { 111} recrystallization texture, so deep-draw ductility obviously worsens.

In Cold Rolled Sheet Steel of the present invention, thereby obtain ferrite and martensitic two-phase microstructure, preferably carry out the cooling of recrystallization annealing with the rate of cooling that is not less than 5 ℃/s in order to form martensitic phase.

On the other hand, in Enplate of the present invention, preferably after above-mentioned recrystallization annealing, be quenched to 380-530 ℃.When quench stop temperature and be lower than 380 ℃ the time, occur defective plating easily, and when stopping temperature and surpass 530 ℃, appearance is inhomogeneous easily on coating surface.And, thereby obtain ferrite and martensitic two-phase microstructure in order to produce martensitic phase, preferably rate of cooling is not less than 5 ℃/s.After above-mentioned quenching, undertaken zinc-plated by dipping in plating tank.In this case, the 0.12-0.145 weight % preferably of the aluminum concentration in the plating tank.When the aluminum concentration in the zinc bath during less than 0.12 weight %, alloying is excessively carried out, and coating adhesion (anti-efflorescence) aggravates, and when aluminum concentration surpasses 0.145 weight %, occurs defective coating easily.

After zinc-plated, also coating is carried out Alloying Treatment.And, preferably carry out Alloying Treatment so that the iron level in the coating is 9-12%.

As Alloying Treatment, preferably carry out the alloying of zinc coating to 450-550 ℃ temperature range by reheat.After the Alloying Treatment, preferably be cooled to 300 ℃ with the rate of cooling that is not less than 5 ℃/s.At high temperature carry out Alloying Treatment and be difficult to form martensitic phase, and might cause that steel sheet ductility worsens, and when the alloying temperature was lower than 450 ℃, the slower development of alloying and productivity were tending towards descending.And, when the rate of cooling after the Alloying Treatment is minimum, forms martensite and become difficult.For this reason, preferably be not less than 5 ℃/s from the rate of cooling temperature range to 300 ℃ after the Alloying Treatment.

And, if require further to improve plating performance, after preferably cold rolling and before carrying out continuous zinc coating, in the continuous annealing service line, anneal independently, subsequently, remove the composition enriched layer in the steel that forms on the surface of thin steel sheet by pickling, after this in the continuous zinc coating service line, carry out above-mentioned processing.In this case, can be in pickling line or be arranged in the pickling tub in the continuous zinc coating service line and carry out pickling.And for fear of forming oxide skin, the atmosphere in the continuous annealing service line is used the H that contains some per-cents usually preferably with respect to the steel-sheet reducing atmosphere ₂Nitrogen just enough.Preferably anneal under the condition below, the temperature that steel sheet reaches in the continuous annealing service line is not less than the A that depends on composition of steel _C1Transition point.Because need by in the continuous annealing service line, form the two-phase microstructure impel on the surface of thin steel sheet the alloying element enrichment and in inferior looks the enrichment alloying element.In the steel sheet after in the continuous annealing service line, annealing, a kind of like this trend is arranged, thereby the phosphorous diffusion in the steel constituent is separated out on surface of thin steel sheet, and silicon, manganese, chromium etc. are with the form enrichment of oxide compound, so preferably remove the enriched layer that forms by pickling on surface of thin steel sheet.Then, in the continuous zinc coating service line, carry out annealing same as described above.In order to form, preferably in that (two-phase region of α+γ) is at A as the microstructural feature of two-phase _C1Transition point is to A _C3In the temperature range of transition point, in the continuous zinc coating service line, anneal.In this case, in continuous annealing service line and continuous zinc coating service line, all be not less than A _C1Carry out the annealed reason under the transition point and form the microstructural fact of aforesaid two-phase due to.In case by form the enrichment of element position that forms conduct time looks as final microstructural two-phase microstructure in the continuous annealing service line, the enrichment alloying element is possible to a certain degree extremely on this position so.It is desirable to is enough to obtain and two-phase microstructure identical in cooled the finished product, so near enrichment alloying element grain circle ternary point (point of crossing on grain formation grain circle by three) more preferably.After this, when in the continuous zinc coating service line, when annealing in the two-phase region, further enrichment alloying element in inferior looks or γ-mutually, therefore during cooling process, γ-be transformed into easily mutually martensitic phase.And term used herein " alloying element " refers to for example such substitutional alloy element such as manganese, molybdenum, and this has caused and has occurred the situation of diffusion hardly, and in order to reduce yield ratio, occurs enrichment easily under the temperature of annealing steps.

And, can also to after Cold Rolled Sheet Steel after the recrystallization annealing processing and the zinc-plated processing or the Enplate after the Alloying Treatment to carry out surface tempering rolling to be not more than 10% rolling rate of compression, to revise shape and to adjust surface roughness etc.And Cold Rolled Sheet Steel of the present invention not only can be with the Cold Rolled Sheet Steel that acts on processing, but also can be with the surface treated steel-sheet blank that acts on processing.Except above-mentioned Enplate (comprising the alloy steel sheet), be Tinplate, porcelain system enamel etc. as the surface treatment steel sheet that is used to process.Even it is also no problem with for example resin or lipid layer, various coating, plating etc. they to be handled.And, in order to improve chemical transformation performance, weldability, punching formation property, erosion resistance etc., after zinc-plated, can carry out special processing to Enplate of the present invention.

The accompanying drawing summary

Fig. 1 a is the figure that vanadium and carbon content influence Lankford value (r-value) in the explanation steel.

Fig. 1 b be in the explanation steel vanadium and carbon content to the figure of yield ratio (YR=yielding stress (YS)/tensile stress (TS) * 100 (%)) influence.

Fig. 2 a illustrates that in the high strength dual phase Cold Rolled Sheet Steel of TS:590MPa grade and TS:780Mpa grade, the relation between niobium, titanium and the content of vanadium is to the figure of tensile strength (TS) influence.

Fig. 2 b illustrates that in the high strength dual phase Cold Rolled Sheet Steel of TS:590MPa grade and TS:780Mpa grade, the relation between niobium, titanium and the content of vanadium is to the figure of Lankford value (TS) influence.

Implement best mode of the present invention

Manufacturing has each molten steel of forming shown in the table 1-4 in converter, and they is carried out continuous casting handle to obtain steel ingot.In this case, in order to carry out the test to Cold Rolled Sheet Steel, preparation has every kind of steel sheet forming shown in table 1 and 2, and in order to carry out the test to Enplate, preparation has every kind of steel sheet forming shown in table 3 and 4.Particularly in order to obtain TS respectively: be not less than Cold Rolled Sheet Steel and the Enplate of 780MPa, the steel ingot shown in the preparation table 2 and 4.Then, steel ingot is heated to 1150 ℃ and in the finish rolling texturing temperature in hot-rolled step: 900 ℃ and coiling temperature: carrying out hot rolling under 650 ℃ the condition, is 4.0 millimeters hot rolled strip thereby obtain thickness.Subsequently, the pickling hot rolled strip, and in cold rolling step, carry out cold rollingly with 70% rolling rate of compression, be 1.2 millimeters cold rolled strip or Cold Rolled Sheet Steel thereby obtain thickness.Then, in the continuous annealing service line, under the annealing temperature shown in table 5 and 6, each Cold Rolled Sheet Steel in the his-and-hers watches 1 and 2 carries out recrystallization annealing.Under 0.8% rolling rate of compression, the Cold Rolled Sheet Steel of such acquisition is further carried out temper rolling.With respect to Enplate, under the annealing temperature shown in table 7 and 8, each Cold Rolled Sheet Steel in the his-and-hers watches 3 and 4 carries out recrystallization annealing, and in the continuous zinc coating service line, carries out zinc-plated in aluminum concentration is 0.13% plating tank.And, with respect to a part of steel sheet (the 52nd, 68,69 and No. 70 steel sheet in the table 7), in the continuous annealing service line, under 830 ℃ the steel sheet after cold rolling is being annealed, in the continuous zinc coating service line, carry out pickling and annealing again, and aluminum concentration is under 0.13% the condition, to carry out zinc-plated in plating tank under 480 ℃ plating tank temperature, further with 0.8% rolling rate of compression, the steel band (Enplate) of such acquisition is carried out temper rolling.With respect to 75 and No. 77 steel sheets in the table 7, after zinc-plated, under 520 ℃ alloying temperature, they are carried out Alloying Treatment.

Cut away a testpieces from the steel band that obtains, by using opticmicroscope or scanning electronic microscope, microstructure perpendicular to the cross section (cross section C) of rolling direction is carried out imaging, use image analysis apparatus to measure as the texture ratio of the ferritic phase of primary phase and the kind and the texture ratio of time looks.In this case, carry out the class mirror polish to being used to observe microstructural sample, and with containing 2%HNO ₃Ethanolic soln carry out etching, be used for then observation.And, also cut away the tension test part of JIS No.5, and carry out tension test according to the definition of JIS Z 2241 from steel band, measure yielding stress (YS), tensile strength (TS), unit elongation (E1), yield ratio (YR) and Lankford value (r-value).These the results are shown among the table 5-8.

Table 1 (a)

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																					C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
	1-A	0.030	0.02	1.55	0.01	0.004	0.032	0.002	0.132	-	-	-	-	-				-	1.04																		-	-	725	860	Acceptable embodiment
1-B															0.028	0.02	1.48			0.01	0.001	0.032	0.002	0.105	0.042	-	-	0.15	-	-	-	1.27	0.44	705	855	Acceptable embodiment
	1-C	0.032	0.03	1.72	0.01	0.005	0.028	0.002	0.085	0.035	0.035	0.05	-	-				-	-																		1.45	1.33	710	850	Acceptable embodiment
1-D															0.020	0.02	1.63			0.01	0.005	0.033	0.002	0.065	-	-	-	-	0.12	0.08	0.76	-	-	715	855	Acceptable embodiment
	1-E	0.031	0.02	1.56	0.01	0.006	0.033	0.002	0.122	0.045	-	-	0.18	-				-	-																		1.30	0.40	705	855	Acceptable embodiment
1-F															0.029	0.02	1.48			0.01	0.003	0.032	0.002	0.210	0.115	0.125	-	-	-	-	-	4.88	1.26	725	855	Comparative Examples
	1-G	0.032	0.02	1.65	0.01	0.004	0.032	0.002	0.045	-	-	-	-	-				-	0.33																		-	-	715	850	Comparative Examples
1-H															0.020	0.22	2.02			0.06	0.004	0.032	0.002	0.132	-	-	-	-	-	-	1.55	-	-	725	860	Acceptable embodiment
	1-I	0.022	0.52	1.85	0.03	0.001	0.032	0.002	0.105	0.042	-	-	0.15	-				-	-																		1.62	0.44	705	865	Acceptable embodiment
1-J															0.028	0.33	1.72			0.01	0.005	0.028	0.002	0.085	0.035	0.035	0.05	-	-	-	-	1.66	1.33	710	860	Acceptable embodiment
	1-K	0.011	0.21	1.53	0.01	0.003	0.028	0.002	0.032	0.030	-	-	-	-				-	-																		1.39	1.03	710	860	Acceptable embodiment
1-L															0.022	0.52	1.52			0.01	0.002	0.033	0.002	0.125	-	0.022	-	-	-	-	-	1.84	0.37	715	865	Acceptable embodiment
	1-M	0.019	0.53	1.43	0.05	0.001	0.032	0.002	0.105	-	-	0.05	0.15	-				-	1.30																		-	-	710	850	Acceptable embodiment

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 1 (b)

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																						C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
1-N	0.021	0.33	1.72	0.06	0.003	0.030	0.002	0.115	-	-	0.05	0.15	0.15	0.15				1.29	-																			-	705	855	Acceptable embodiment
															1-O	0.020	0.41			2.02	0.02	0.002	0.029	0.002	0.072	0.042	0.010	0.05	0.15	0.10	0.10	-	1.64	0.93	715	850	Acceptable embodiment
1-P	0.007	0.35	1.76	0.01	0.005	0.029	0.002	0.073	-	-	-	-	-	-				2.45	-																			-	714	882	Comparative Examples
															1-Q	0.112	0.33			1.74	0.01	0.003	0.028	0.002	0.352	-	-	-	-	-	-	0.74	-	-	714	859	Comparative Examples
1-R	0.021	0.52	1.52	0.01	0.002	0.033	0.002	0.008	-	-	-	-	-	-				0.09	-																			-	722	879	Comparative Examples
															1-S	0.023	0.53			1.43	0.05	0.001	0.032	0.002	0.622	-	-	-	-	-	-	6.36	-	-	723	972	Comparative Examples
1-T	0.021	0.33	1.72	0.06	0.003	0.030	0.002	0.049	0.0005	-	-	-	-	-				-	0.56																			0.01	714	910	Acceptable embodiment
															I-U	0.025	0.41			1.75	0.04	0.002	0.029	0.002	0.041	0.325	-	-	-	-	-	-	3.74	8.69	716	891	Comparative Examples
1-V	0.019	0.35	1.76	0.05	0.001	0.032	0.002	0.052	-	0.0005	-	-	-	-				-	0.66																			0.02	714	906	Acceptable embodiment
															1-W	0.023	0.33			1.72	0.06	0.003	0.030	0.002	0.033	-	0.306	-	-	-	-	-	6.99	19.7	714	1033	Comparative Examples
1-X	0.018	0.02	1.48	0.01	0.003	0.032	0.002	0.030	0.001	0.001	-	-	-	-				-	0.43																			0.07	708	863	Comparative Examples
															1-Y	0.021	0.02			1.65	0.01	0.004	0.032	0.002	0.329	-	-	-	-	-	-	3.69	-	-	706	886	Comparative Examples

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 2

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																					C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
	2-A	0.039	0.50	2.85	0.01	0.005	0.031	0.002	0.151	-	-	-	-	-				-	0.91																		-	-	707	842	Acceptable embodiment
2-B															0.038	0.75	2.52			0.01	0.001	0.035	0.002	0.088	0.121	-	-	0.29	-	-	-	1.37	1.51	718	868	Acceptable embodiment
	2-C	0.042	0.74	2.53	0.01	0.006	0.033	0.002	0.092	0.110	0.152	0.09	-	-				-	-																		3.00	4.82	719	915	Acceptable embodiment
2-D															0.041	0.70	2.55			0.01	0.008	0.032	0.002	0.087	-	0.064	-	-	0.08	0.1	-	1.28	1.56	715	875	Acceptable embodiment
	2-E	0.048	0.72	2.52	0.01	0.005	0.034	0.002	0.153	0.202	0.005	-	0.31	-				-	-																		1.89	1.52	717	870	Acceptable embodiment
2-F															0.040	0.77	2.55			0.01	0.007	0.036	0.002	0.524	0.193	0.262	-	-	-	-	-	7.60	1.47	718	972	Comparative Examples
	2-G	0.038	0.73	2.56	0.01	0.006	0.033	0.002	0.040	0.011	0.009	-	-	-				-	-																		0.44	0.78	717	851	Comparative Examples
2-H															0.043	0.95	2.95			0.05	0.005	0.032	0.002	0.095	0.002	0.119	-	0.27	-	-	-	1.92	2.68	717	931	Acceptable embodiment
	2-I	0.042	0.82	2.78	0.04	0.009	0.035	0.002	0.141	0.045	0.053	-	-	-				-	-																		1.70	1.15	717	900	Acceptable embodiment
2-J															0.048	0.91	2.73			0.04	0.006	0.036	0.002	0.033	0.185	0.155	0.13	0.13	0.12	0.11	-	2.77	16.13	722	932	Acceptable embodiment
	2-K	0.042	0.82	2.78	0.04	0.009	0.035	0.002	0.008	-	-	-	-	-				-	0.04																		-	-	717	866	Comparative Examples
2-L															0.038	0.91	2.73			0.04	0.006	0.036	0.002	0.522	-	-	-	-	-	-	3.23	-	-	720	923	Comparative Examples
	2-M	0.038	0.76	2.57	0.03	0.001	0.034	0.002	0.087	0.0005	-	-	-	-				-	-																		0.54	0.01	718	868	Acceptable embodiment
2-N															0.039	0.76	2.55			0.03	0.001	0.035	0.002	0.032	0.056	-	-	-	-	-	-	0.56	1.92	718	868	Acceptable embodiment
	2-O	0.042	0.73	2.49	0.03	0.001	0.036	0.002	0.092	0.382	-	-	-	-				-	-																		2.86	4.55	718	868	Acceptable embodiment
2-P															0.043	0.75	2.52			0.03	0.001	0.035	0.002	0.088	0.453	-	-	-	-	-	-	3.20	5.65	718	868	Comparative Examples
	2-Q	0.041	0.70	2.55	0.03	0.002	0.032	0.002	0.098	-	0.0005	-	-	-				-	-																		0.57	0.01	715	875	Acceptable embodiment
2-R															0.038	0.71	2.58			0.03	0.002	0.030	0.002	0.025	-	0.037	-	-	-	-	-	0.64	3.15	715	875	Acceptable embodiment
	2-S	0.039	0.74	2.57	0.04	0.002	0.030	0.002	0.079	-	0.186	-	-	-				-	-																		2.86	5.00	715	875	Acceptable embodiment
2-T															0.042	0.71	2.51			0.02	0.002	0.029	0.002	0.089	-	0.356	-	-	-	-	-	4.74	8.50	715	875	Comparative Examples

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 3 (a)

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																					C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
	3-A	0.028	0.02	1.55	0.01	0.003	0.034	0.002	0.121	-	-	-	-	-				-	1.02																		-	-	725	860	Acceptable embodiment
3-B															0.030	0.02	1.46			0.01	0.002	0.035	0.002	0.108	0.041	-	-	0.16	-	-	-	1.20	0.42	705	855	Acceptable embodiment
	3-C	0.031	0.03	1.70	0.01	0.005	0.028	0.002	0.086	0.036	0.033	0.06	-	-				-	-																		1.48	1.27	710	850	Acceptable embodiment
3-D															0.021	0.02	1.65			0.01	0.005	0.034	0.002	0.068	-	-	-	-	0.14	0.07	0.76	-	-	715	855	Acceptable embodiment
	3-E	0.032	0.02	1.52	0.01	0.004	0.033	0.002	0.124	0.044	-	-	0.15	-				-	-																		1.27	0.39	705	855	Acceptable embodiment
3-F															0.026	0.02	1.52			0.01	0.003	0.035	0.002	0.122	0.112	0.122	-	-	-	-	-	4.56	3.13	725	855	Comparative Examples
	3-G	0.032	0.02	1.62	0.01	0.005	0.032	0.002	0.042	-	-	-	-	-				-	0.31																		-	-	715	850	Comparative Examples
3-H															0.021	0.21	2.02			0.06	0.003	0.030	0.002	0.130	-	-	-	-	-	-	1.46	-	-	725	860	Acceptable embodiment
	3-I	0.024	0.52	1.88	0.04	0.001	0.032	0.002	0.105	0.033	-	-	0.16	-				-	-																		1.38	0.34	705	860	Acceptable embodiment
3-J															0.026	0.32	1.72			0.01	0.004	0.026	0.002	0.088	0.035	0.032	0.08	-	-	-	-	1.76	1.21	710	860	Acceptable embodiment
	3-K	0.020	0.70	1.55	0.01	0.003	0.028	0.002	0.073	0.045	-	-	-	-				-	-																		1.44	0.68	715	870	Acceptable embodiment
3-L															0.012	0.21	1.51			0.01	0.002	0.033	0.002	0.055	-	0.018	-	-	-	-	-	1.83	0.70	710	865	Acceptable embodiment
	3-M	0.018	0.50	1.56	0.03	0.004	0.035	0.002	0.108	-	-	0.05	0.15	-				-	1.41																		-	-	710	860	Acceptable embodiment

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 3 (b)

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																						C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
3-N	0.020	0.39	1.73	0.05	0.001	0.031	0.002	0.110	-	-	0.05	0.15	0.15	0.15				1.29	-																			-	705	865	Acceptable embodiment
															3-O	0.021	0.28			1.95	0.02	0.005	0.029	0.002	0.075	0.038	0.01	0.05	0.15	0.10	0.10	-	1.55	0.84	715	865	Acceptable embodiment
3-P	0.008	0.32	1.75	0.01	0.005	0.032	0.002	0.075	-	-	-	-	-	-				2.21	-																			-	714	881	Comparative Examples
															3-Q	0.095	0.34			1.73	0.01	0.003	0.029	0.002	0.361	-	-	-	-	-	-	0.89	-	-	714	872	Comparative Examples
3-R	0.023	0.49	1.54	0.01	0.002	0.030	0.002	0.007	-	-	-	-	-	-				0.07	-																			-	722	874	Comparative Examples
															3-S	0.024	0.51			1.47	0.03	0.001	0.031	0.002	0.597	-	-	-	-	-	-	5.85	-	-	721	949	Comparative Examples
3-T	0.022	0.35	1.75	0.05	0.003	0.029	0.002	0.109	0.0005	-	-	-	-	-				-	1.17																			0.01	714	906	Acceptable embodiment
															3-U	0.023	0.44			1.78	0.04	0.003	0.027	0.002	0.065	0.319	-	-	-	-	-	-	4.24	5.38	717	891	Comparative Examples
3-V	0.021	0.35	1.73	0.05	0.001	0.034	0.002	0.099	-	0.0005	-	-	-	-				-	1.12																			0.01	715	913	Acceptable embodiment
															3-W	0.025	0.36			1.77	0.05	0.002	0.032	0.002	0.132	-	0.321	-	-	-	-	-	7.66	5.17	715	1031	Comparative Examples
3-X	0.020	0.02	1.51	0.01	0.003	0.033	0.002	0.035	0.001	0.001	-	-	-	-				-	0.45																			0.09	707	866	Comparative Examples
															3-Y	0.023	0.02			1.66	0.01	0.003	0.035	0.002	0.308	-	-	-	-	-	-	3.15	-	-	707	882	Comparative Examples

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 4

Grade of steel	Chemical ingredients (weight %)														X *1	Y *2	Z *3	Transition point (℃)		Remarks
																					C	Si	Mn	P	S	Al	N	V	Nb	Ti	Cr	Mo	Cu	Ni	A C1	A C3
	4-A	0.038	0.48	2.88	0.01	0.004	0.033	0.002	0.158	-	-	-	-	-				-	0.98																		-	-	706	842	Acceptable embodiment
4-B															0.041	0.77	2.51			0.01	0.001	0.035	0.002	0.056	0.171	-	-	0.31	-	-	-	1.40	3.35	719	865	Acceptable embodiment
	4-C	0.040	0.76	2.49	0.01	0.007	0.034	0.002	0.068	0.120	0.125	0.09	-	-				-	-																		2.74	5.84	720	905	Acceptable embodiment
4-D															0.038	0.72	2.54			0.01	0.009	0.033	0.002	0.085	-	0.058	-	-	0.08	0.07	-	1.29	1.45	716	876	Acceptable embodiment
	4-E	0.049	0.74	2.53	0.01	0.006	0.036	0.002	0.039	0.075	0.005	-	0.31	-				-	-																		0.63	2.38	717	859	Acceptable embodiment
4-F															0.039	0.75	2.55			0.01	0.007	0.035	0.002	0.183	0.191	0.260	-	-	-	-	-	5.70	4.16	718	971	Comparative Examples
	4-G	0.046	0.73	2.57	0.01	0.007	0.038	0.002	0.011	0.013	0.015	-	-	-				-	-																		0.29	4.19	717	851	Comparative Examples
4-H															0.039	0.93	2.95			0.05	0.004	0.039	0.002	0.016	0.003	0.108	-	0.27	-	-	-	1.50	14.55	717	922	Acceptable embodiment
	4-I	0.041	0.80	2.80	0.05	0.009	0.033	0.002	0.138	0.042	0.065	-	-	-																							1.85	1.33	716	909	Acceptable embodiment
4-J															0.047	0.92	2.78			0.04	0.006	0.034	0.002	0.025	0.175	0.143	0.15	-	-	-	-	2.61	19.83	723	923	Acceptable embodiment
	4-K	0.043	0.84	2.76	0.04	0.007	0.034	0.002	0.007	-	-	-	-	-				-	0.04																		-	-	718	867	Comparative Examples
4-L															0.038	0.93	2.75			0.04	0.006	0.035	0.002	0.553	-	-	-	-	-	-	3.42	-	-	721	924	Comparative Examples
	4-M	0.042	0.80	2.65	0.02	0.003	0.031	0.002	0.096	0.0005	-	-	-	-				-	-																		0.54	0.01	719	865	Acceptable embodiment
4-N															0.041	0.81	2.68			0.02	0.003	0.030	0.002	0.029	0.065	-	-	-	-	-	-	0.58	2.46	719	865	Acceptable embodiment
	4-O	0.043	0.78	2.67	0.03	0.003	0.029	0.002	0.087	0.295	-	-	-	-				-	-																		2.25	3.72	719	865	Acceptable embodiment
4-P															0.041	0.77	2.69			0.02	0.002	0.030	0.002	0.079	0.521	-	-	-	-	-	-	3.73	7.23	719	865	Comparative Examples
	4-Q	0.039	0.76	2.74	0.03	0.003	0.031	0.002	0.105	-	0.0005	-	-	-				-	-																		0.64	0.01	716	876	Acceptable embodiment
4-R															0.043	0.79	2.74			0.02	0.004	0.033	0.002	0.035	-	0.042	-	-	-	-	-	0.68	2.55	716	876	Acceptable embodiment
	4-S	0.040	0.80	2.75	0.03	0.002	0.032	0.002	0.087	-	0.182	-	-	-				-	-																		2.79	4.45	716	876	Acceptable embodiment
4-T															0.038	0.81	2.77			0.02	0.003	0.032	0.002	0.089	-	0.290	-	-	-	-	-	4.37	6.92	716	876	Comparative Examples

(notes) ^*1:X=(V/51)/(C/12)

^*2：Y＝(V/51+2×Nb/93+2×Ti/48)/(C/12)

^*3：Z＝(2×Nb/93+2×Ti/48)/(V/51)

Table 5 (a)

Cold rolling

Steel plate number	Grade of steel	Annealing temperature in the continuous annealing service line (℃)	Microstructure				The mechanical property of Cold Rolled Sheet Steel					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													1	1-A	830	92	M	8	8	330	600	31	55	1.8	Inventive embodiments
2	1-B	830	90	M	10	10	330	610	30	54	1.8	Inventive embodiments
													3	1-B	980	0	P，B，M	15	100	650	720	22	90	0.9	Comparative Examples
4	1-B	680	100	-	0	0	450	530	29	85	0.8	Comparative Examples
													5	1-C	830	92	M	8	8	340	600	31	57	1.8	Inventive embodiments
6	1-D	830	90	M	10	10	330	610	30	54	1.4	Inventive embodiments
													7	1-E	830	92	M	8	8	310	570	33	54	1.7	Inventive embodiments
8	1-F	830	100	-	0	0	510	600	27	85	1.8	Comparative Examples
													9	1-G	830	93	M	7	7	330	610	31	54	0.8	Comparative Examples
10	1-H	850	92	M	8	8	350	630	29	56	1.9	Inventive embodiments
													11	1-I	850	93	M	7	7	330	620	30	53	1.9	Inventive embodiments
12	1-J	850	92	M	8	8	330	610	33	54	1.8	Inventive embodiments
													13	1-K	830	92	M	8	8	245	450	38	54	1.9	Inventive embodiments
14	1-L	830	93	M	7	7	330	605	30	55	1.8	Inventive embodiments

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 5 (b)

Cold rolling

Steel plate number	Grade of steel	Annealing temperature in the continuous annealing service line (℃)	Microstructure				The mechanical property of Cold Rolled Sheet Steel					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													15	1-M	830	92	M	8	8	340	620	30	55	1.7	Inventive embodiments
16	1-N	830	93	M	7	7	320	600	31	53	1.7	Inventive embodiments
													17	1-O	830	92	M，B	6	8	340	625	29	54	1.8	Comparative Examples
18	1-P	830	100	-	0	0	425	520	34	82	1.9	Comparative Examples
													19	1-Q	830	65	M	35	35	395	670	29	59	0.8	Comparative Examples
20	1-R	850	69	M	31	31	370	620	30	60	0.8	Comparative Examples
													21	1-S	850	100	-	0	0	495	615	30	80	1.7	Comparative Examples
22	1-T	850	92	M	8	8	355	575	32	62	1.7	Inventive embodiments
													23	1-U	850	100	-	0	0	470	580	31	81	1.8	Comparative Examples
24	1-V	830	91	M	9	9	350	570	32	61	1.7	Inventive embodiments
													25	1-W	850	100	-	0	0	480	595	31	81	1.8	Comparative Examples
26	1-X	830	72	M	28	28	350	560	31	63	0.8	Comparative Examples
													27	1-Y	830	100	-	0	0	475	590	30	81	1.7	Comparative Examples

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 6 (a)

Cold rolling

Steel plate number	Grade of steel	Annealing temperature in the continuous annealing service line (℃)	Microstructure				The mechanical property of Cold Rolled Sheet Steel					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													28	2-A	780	90	M	10	10	560	825	19	68	1.1	Inventive embodiments
29	2-B	780	87	M	13	13	550	810	19	68	1.3	Inventive embodiments
													30	2-B	950	0	P，B，M	19	100	740	860	16	86	0.7	Comparative Examples
31	2-B	680	100	-	0	0	625	770	22	81	0.8	Comparative Examples
													32	2-C	750	88	M	12	12	540	805	20	67	1.3	Inventive embodiments
33	2-D	760	88	M	12	12	545	810	19	67	1.2	Inventive embodiments
													34	2-E	770	87	M	13	13	550	820	20	67	1.3	Inventive embodiments
35	2-F	780	100	-	0	0	660	830	19	80	1.4	Comparative Examples
													36	2-G	780	69	M	31	31	540	820	20	66	0.7	Comparative Examples
37	2-H	760	81	M	19	19	620	930	15	67	1.3	Inventive embodiments
													38	2-I	780	83	M	17	17	590	860	17	69	1.1	Inventive embodiments

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 6 (b)

Cold rolling

Steel plate number	Grade of steel	Annealing temperature in the continuous annealing service line (℃)	Microstructure				The mechanical property of Cold Rolled Sheet Steel					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													39	2-J	780	87	M	13	13	445	660	27	67	1.4	Inventive embodiments
40	2-K	760	68	M	32	32	570	850	18	67	0.8	Comparative Examples
													41	2-L	780	100	-	0	0	690	835	19	83	1.3	Comparative Examples
42	2-M	780	85	M	15	15	525	805	20	65	1.1	Inventive embodiments
													43	2-N	760	88	M	12	12	530	800	20	66	1.3	Inventive embodiments
44	2-O	780	90	M	10	10	525	790	21	66	1.3	Inventive embodiments
													45	2-P	780	100	-	0	0	650	795	21	82	1.3	Comparative Examples
46	2-Q	760	87	M	13	13	540	81 0	19	67	1.1	Inventive embodiments
													47	2-R	760	88	M	12	12	545	815	15	67	1.3	Inventive embodiments
48	2-S	780	90	M	10	10	540	810	19	67	1.3	Inventive embodiments
													49	2-T	780	100	-	0	0	665	785	20	85	1.4	Comparative Examples

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 7 (a)

Zinc-plated

Steel plate number	Grade of steel	Annealing temperature in the continuous zinc coating service line (℃)	Microstructure				The mechanical property of Enplate					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													50	3-A	830	92	M	8	8	330	610	31	54	1.7	Inventive embodiments
51	3-B	830	90	M	10	10	330	620	30	53	1.7	Inventive embodiments
													52	3-B	830	92	M	8	8	350	630	30	56	1.6	Inventive embodiments
53	3-B	980	0	P，B，M	12	100	660	720	22	92	0.9	Comparative Examples
													54	3-B	680	100	-	0	0	460	540	28	85	0.8	Comparative Examples
55	3-C	830	90	M	10	10	340	610	31	56	1.7	Inventive embodiments
													56	3-D	830	92	M	8	8	340	620	30	55	1.4	Inventive embodiments
57	3-E	830	94	M	6	6	320	580	32	55	1.6	Inventive embodiments
													58	3-F	830	100	-	0	0	510	600	27	85	1.7	Comparative Examples
59	3-G	830	92	M	8	8	330	610	30	54	0.8	Comparative Examples
													60	3-H	850	93	M	7	7	340	630	30	54	1.8	Inventive embodiments
61	3-I	850	92	M	8	8	340	620	31	55	1.8	Inventive embodiments
													62	3-J	850	92	M	8	8	320	610	31	52	1.7	Inventive embodiments
63	3-K	830	92	M，B	6	8	330	610	30	54	1.6	Inventive embodiments
													64	3-L	830	92	M	8	8	248	450	37	55	1.7	Inventive embodiments
65	3-M	830	93	M	7	7	340	620	30	55	1.6	Inventive embodiments

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 7 (b)

Zinc-plated

Steel plate number	Grade of steel	Annealing temperature in the continuous zinc coating service line (℃)	Microstructure				The mechanical property of Enplate					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													66	3-N	830	92	M	8	8	320	600	31	53	1.6	Inventive embodiments
67	3-O	830	93	M	7	7	340	625	29	54	1.7	Inventive embodiments
													68	3-H	830	92	M	8	8	340	620	30	55	1.8	Inventive embodiments
69	3-K	830	93	M	7	7	320	600	31	53	1.6	Inventive embodiments
													70	3-M	830	92	M	8	8	320	610	31	52	1.6	Inventive embodiments
71	3-P	830	100	-	0	0	420	510	34	82	1.8	Comparative Examples
													72	3-Q	830	66	M	34	34	390	670	27	58	0.8	Comparative Examples
73	3-R	850	68	M	32	32	385	615	30	63	0.8	Comparative Examples
													74	3-S	850	100	-	0	0	500	605	31	83	1.6	Comparative Examples
75	3-T	850	91	M	9	9	350	580	31	60	1.7	Inventive embodiments
													76	3-U	850	100	-	0	0	480	575	32	83	1.6	Comparative Examples
77	3-V	830	91	M	9	9	340	580	31	59	1.7	Inventive embodiments
													78	3-W	850	100	-	0	0	490	600	30	82	1.7	Comparative Examples
79	3-X	830	70	M	30	30	340	565	32	60	0.8	Comparative Examples
													80	3-Y	830	100	-	0	0	490	600	30	82	1.7	Comparative Examples

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 8 (a)

Zinc-plated

Steel plate number	Grade of steel	Annealing temperature in the continuous zinc coating service line (℃)	Microstructure				The mechanical property of Enplate					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													81	4-A	780	91	M	9	9	560	815	19	69	1.1	Inventive embodiments
82	4-B	780	89	M	11	11	555	805	19	69	1.4	Inventive embodiments
													83	4-B	950	0	P，B，M	21	100	735	850	16	86	0.8	Comparative Examples
84	4-B	680	100	-	0	0	620	760	22	82	0.8	Comparative Examples
													85	4-C	4	89	M	11	11	545	800	20	68	1.3	Inventive embodiments
86	4-D	760	88	M	12	12	550	805	19	68	1.4	Inventive embodiments
													87	4-E	770	90	M	10	10	550	810	20	68	1.3	Inventive embodiments
88	4-F	780	100	-	0	0	675	815	19	83	1.5	Comparative Examples
													89	4-G	780	92	M	8	8	550	810	20	68	0.8	Comparative Examples
90	4-H	760	83	M	17	17	635	935	15	68	1.3	Inventive embodiments
													91	4-I	780	85	M	15	15	590	855	17	69	1.1	Inventive embodiments

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

Table 8 (b)

Zinc-plated

Steel plate number	Grade of steel	Annealing temperature in the continuous zinc coating service line (℃)	Microstructure				The mechanical property of Enplate					Remarks
													The ferrite phase	Inferior looks			Tensile properties
			Area is than (%)	Kind *1	Martensitic area is than (%)	The area of inferior looks is than (%)	YS (MPa)	TS (MPa)	E1 (％)	YR (％)	The r-value
													92	4-J	780	85	M	15	15	440	665	25	68	1.4	Inventive embodiments
93	4-K	760	67	M	33	33	560	860	18	65	0.8	Comparative Examples
													94	4-L	780	100	-	0	0	695	840	19	83	1.4	Comparative Examples
95	4-M	780	86	M	14	14	510	810	20	63	1.1	Inventive embodiments
													96	4-N	760	89	M	11	11	525	800	20	66	1.3	Inventive embodiments
97	4-O	780	89	M	11	11	525	795	20	66	1.3	Inventive embodiments
													98	4-P	780	100	-	0	0	660	805	20	82	1.4	Comparative Examples
99	4-Q	760	87	M	13	13	525	810	19	65	1.1	Inventive embodiments
													100	4-R	760	86	M	14	14	530	810	19	65	1.2	Inventive embodiments
101	4-S	780	89	M	11	11	540	820	18	66	1.3	Inventive embodiments
													102	4-T	780	100	-	0	0	660	790	20	84	1.3	Comparative Examples

(notes) ^*1:F is the abbreviation of ferrite phase, and M is the abbreviation of martensitic phase,

P is the abbreviation of perlite phase, and B is the abbreviation of bainite phase.

From the result shown in table 5 and 6 as can be seen, Cold Rolled Sheet Steel among all embodiment of the present invention all has low yielding stress (YS), high unit elongation and low yield ratio (YR), further also show high r-value and excellent deep-draw ductility, and had the tensile strength (TS) that is not less than 440MPa.On the contrary, in the Comparative Examples outside the scope of the invention, yielding stress (YS) height, (E1) is low for unit elongation, or the r-value is low.Particularly, be not less than in the high-strength steel sheet of 780MPa at the TS shown in the table 6, observe be accompanied by highly enriched, the r-value has reduction slightly, for example uses No. 28 steel sheet containing vanadium but not contain that the 2-A steel of niobium and titanium makes and use to contain vanadium, niobium and titanium and satisfies that 0.5 * C/12≤(relational expression of V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12 also satisfies (No. 38 steel sheet that the 2-I steel of the relational expression of 2 * Nb/93+2 * Ti/48)/(V/51)≤0.5 is made.On the other hand, contain vanadium, niobium and titanium and satisfy simultaneously that 0.5 * C/12≤(V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12 and 1.5≤(in the 29th, 32,33 and No. 34 steel sheet that 2-B, 2-C, 2-D and the 2-E steel of the relational expression of 2 * Nb/93+2 * Ti/48)/(V/51)≤15 made, r-is worth to improve in use.

And, for the results are shown in table 7 and 8 that Enplate obtains.Even in these Enplates, also obtain to be similar to the result of above-mentioned Cold Rolled Sheet Steel.

In steel sheet of the present invention, even carry out the zinc-plated excellent performance that also can obtain by production process.

Industrial applicibility

The present invention has produced significant effect industrial, namely can stably make high strength cold-rolled sheet metal and the galvanized sheet metal with excellent deep-draw ductility. When cold-reduced sheet of the present invention and galvanized sheet metal are used for vehicle parts, easily stamping effect are arranged, and go far towards to reduce the weight of car body.

Claims (27)

1. has excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, it is characterized in that this steel-sheet composition comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is the relation that vanadium and carbon satisfy 0.5 * C/12≤V/51≤3 * C/12, all the other are iron and unavoidable impurities, and have by as the ferritic phase of primary phase with comprise and the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase.

2. has excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, it is characterized in that: this steel-sheet is formed and is comprised carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, further also comprise niobium: greater than 0 weight % but be not more than 0.3 weight % and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, condition is a vanadium, niobium, titanium and carbon satisfy the relation of 0.5 * C/12≤V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12, all the other are iron and unavoidable impurities, and have by as the ferritic phase of primary phase with comprise and the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase.

3. according to the excellent deep-draw ductile of having of claim 2 high strength dual phase Cold Rolled Sheet Steel, wherein steel sheet comprises niobium: 0.001-0.3 weight % and titanium: one or both among the 0.001-0.3 weight % amount to and are no more than 0.3 weight %.

4. according to the excellent deep-draw ductile of having of claim 2 high strength dual phase Cold Rolled Sheet Steel, wherein steel sheet comprises carbon: 0.03-0.08 weight %, silicon: 0.1-2.0 weight %, manganese: 1.0-3.0 weight %, phosphorus: be no more than 0.05 weight % and sulphur: be no more than 0.01 weight %, condition is that vanadium, niobium and titanium satisfy 1.5≤(relation of 2 * Nb/93+2 * Ti/48)/(V/51)≤15.

5. has excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, it is characterized in that this steel-sheet composition comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is the relation that vanadium and carbon satisfy 0.5 * C/12≤V/51≤3 * C/12, all the other are iron and unavoidable impurities, and have by as the ferritic phase of primary phase with comprise and the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase, wherein steel sheet further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

6. has excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, it is characterized in that: this steel-sheet is formed and is comprised carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 amount amount %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, further also comprise niobium: greater than 0 weight % but be not more than 0.3 weight % and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, condition is a vanadium, niobium, titanium and carbon satisfy the relation of 0.5 * C/12≤V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12, all the other are iron and unavoidable impurities, and have by as the ferritic phase of primary phase with comprise and the microstructure of whole microstructural area than the secondary phase composite that is not less than 1% martensitic phase, wherein steel sheet further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

7. a manufacturing has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, and it comprises hot-rolled steel ingot, pickling, cold rolling, then at A _C1Transition point is to A _C3Carry out continuous annealing in the temperature range of transition point; Described steel ingot comprises C:0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is the relation that vanadium and carbon satisfy 0.5 * C/12≤V/51≤3 * C/12, and all the other are iron and unavoidable impurities.

8. a manufacturing has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, and it comprises hot-rolled steel ingot, pickling, cold rolling, then at A _C1Transition point is to A _C3Carry out continuous annealing in the temperature range of transition point; Described steel ingot comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, and further comprise niobium: greater than 0 weight % but be not more than 0.3 weight % and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, condition is a vanadium, niobium, titanium and carbon satisfy that 0.5 * C/12≤(relation of V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12, all the other are iron and unavoidable impurities.

9. manufacturing according to Claim 8 has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, and wherein steel ingot comprises niobium: 0.001-0.3 weight % and titanium: one or both among the 0.001-0.3 weight % amount to and are no more than 0.3 weight %.

10. manufacturing according to Claim 8 has the method for excellent deep-draw ductile high strength dual phase Cold Rolled Sheet Steel, wherein steel ingot comprises carbon: 0.03-0.08 weight %, silicon: 0.1-2.0 weight %, manganese: 1.0-3.0 weight %, phosphorus: be no more than 0.05 weight % and sulphur: be no more than 0.01 weight %, condition is that vanadium, niobium and titanium satisfy 1.5≤(relation of 2 * Nb/93+2 * Ti/48)/(V/51)≤15.

11. a manufacturing has the method for excellent deep-draw ductility high strength dual phase Cold Rolled Sheet Steel, it comprises hot-rolled steel ingot, pickling, cold rolling, then at A _C1Transition point is to A _C3Carry out continuous annealing in the temperature range of transition point; Described steel ingot comprises C:0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, condition is the relation that vanadium and carbon satisfy 0.5 * C/12≤V/51≤3 * C/12, all the other are iron and unavoidable impurities, and wherein steel ingot further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

12. a manufacturing has the method for excellent deep-draw ductility high strength dual phase Cold Rolled Sheet Steel, it comprises hot-rolled steel ingot, pickling, cold rolling, then at A _C1Transition point is to A _C3Carry out continuous annealing in the temperature range of transition point; Described steel ingot comprises carbon: 0.01-0.08 weight %, silicon: be no more than 2.0 weight %, manganese: be no more than 3.0 weight %, phosphorus: be no more than 0.10 weight %, sulphur: be no more than 0.02 weight %, aluminium: 0.005-0.20 weight %, nitrogen: be no more than 0.02 weight % and vanadium: 0.01-0.5 weight %, and further comprise niobium: greater than 0 weight % but be not more than 0.3 weight % and titanium: greater than 0 weight % but be not more than among the 0.3 weight % one or both, total is no more than 0.3 weight %, condition is a vanadium, niobium, titanium and carbon satisfy 0.5 * C/12≤(relation of V/51+2 * Nb/93+2 * Ti/48)≤3 * C/12, all the other are iron and unavoidable impurities, and wherein steel ingot further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

13. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 1.

14. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 2.

15. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 3.

16. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 4.

17. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 5.

18. have excellent deep-draw ductile high strength dual phase steel plate galvanized, comprise as the electrolytic coating on the steel sheet claimed in the claim 6.

19. a manufacturing has the method for excellent deep-draw ductile high strength dual phase steel plate galvanized, it is characterized in that in the method claimed in claim 7 at A _C1Transition point is to A _C3Carry out zinc-plated after the temperature range continuous annealing of transition point.

20. have the method for excellent deep-draw ductile high strength dual phase steel plate galvanized according to the manufacturing of claim 19, it is characterized in that at cold rolling step with at A _C1Transition point is to A _C3Further comprise a continuous annealing step between the continuous annealing step of transition point temperature scope.

21. a manufacturing has the method for excellent deep-draw ductile high strength dual phase steel plate galvanized, it is characterized in that in the method claimed in claim 8 at A _C1Transition point is to A _C3Carry out zinc-plated after the continuous annealing of transition point temperature scope.

22. have the method for excellent deep-draw ductile high strength dual phase steel plate galvanized according to the manufacturing of claim 21, it is characterized in that at cold rolling step with at A _C1Transition point is to A _C3Further comprise a continuous annealing step between the continuous annealing step of transition point temperature scope.

23. a manufacturing has the method for excellent deep-draw ductile high strength dual phase steel plate galvanized, it is characterized in that in the method claimed in claim 9 at A _C1Transition point is to A _C3Carry out zinc-plated after the continuous annealing of transition point temperature scope.

24. have the method for excellent deep-draw ductile high strength dual phase steel plate galvanized according to the manufacturing of claim 23, it is characterized in that at cold rolling step with at A _C1Transition point is to A _C3Further comprise a continuous annealing step between the continuous annealing step of transition point temperature scope.

25. a manufacturing has the method for excellent deep-draw ductile high strength dual phase steel plate galvanized, it is characterized in that in the method claimed in claim 10 at A _C1Transition point is to A _C3Carry out zinc-plated after the continuous annealing of transition point temperature scope.

26. have the method for excellent deep-draw ductile high strength dual phase steel plate galvanized according to the manufacturing of claim 25, it is characterized in that at cold rolling step with at A _C1Transition point is to A _C3Further comprise a continuous annealing step between the continuous annealing step of transition point temperature scope.

27. have the method for excellent deep-draw ductility high strength dual phase steel plate galvanized according to any one manufacturing among the claim 19-26, wherein steel ingot further comprises in organizing one group or two groups of following A-group and B-:

The A-group: one or both in chromium and the molybdenum amount to and are no more than 2.0 weight %;

The B-group: one or both in the copper and mickel amount to and are no more than 2.0 weight %.

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