CN106103763A

CN106103763A - Formability and the aluminium alloy plate of baking application hardening excellence

Info

Publication number: CN106103763A
Application number: CN201580012219.6A
Authority: CN
Inventors: 穴户久郎; 松本克史; 有贺康博
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2014-03-31
Filing date: 2015-03-23
Publication date: 2016-11-09
Also published as: US20190010581A1; US20170175231A1; WO2015151907A1; KR20160127112A; KR101850234B1; MX2016012707A; CA2941988A1

Abstract

It is an object of the invention to provide 6000 line aluminium alloy plates of the BH after having long-term room-temperature timeliness concurrently and formability.In one embodiment, 6000 line aluminium alloy plates of the specific composition containing Sn can suppress to be helpless to the less Mg Si cluster of intensity, and the bigger Mg Si cluster contributing to intensity can be increased as much as possible, thus give full play to capture and the releasing effect of the atomic vacancy of Sn, suppress long-term room-temperature aging to improve crimping processability, and BH also improves.In another embodiment, the solid solution capacity of Mg+Si is guaranteed containing Sn in 6000 line aluminium alloy plates of specific composition, and make yield tensile ratio as little as less than 0.50, the distribution of sizes of measured atom set body is controlled hence with three-dimensional atom probe field ion microscope, and limit the ratio of atom set body meeting certain condition, thus take into account high BHization and low yield strength ratio.

Description

Formability and the aluminium alloy plate of baking application hardening excellence

Technical field

The present invention relates to Al-Mg-Si-type aluminum alloy plate.Aluminium alloy plate described in the present invention is hot rolled plate and cold-reduced sheet Deng milled sheet, its refer to implement solution treatment and Quenching Treatment etc. quenched after and be coated with carrying out stamping or baking Aluminium alloy plate before dress cure process.It addition, also aluminum is referred to as Al in following record.

Background technology

In recent years, it is contemplated that earth environment etc., the light-weighted social desirability of the vehicles such as automobile is more and more higher.In order to tackle This requirement, as the material of the large car dignity panel structure (outer panels, wainscot) of automobile, except ferrous materials such as steel plates In addition, the application of the aluminium alloy material of formability and baking application hardening excellence and more light weight increases.

In the large car dignity panel structure of this automobile, have studied at hood, mud guard, car door, roof, luggage case AA or even JIS 6000 also using Al-Mg-Si system in the outer panels (outside plate) of lid etc. is (following, the most referred to as 6000 are) Aluminium alloy plate is as thin-walled and high-strength aluminium alloy plate.

This 6000 line aluminium alloy plate must contain Si, Mg, particularly 6000 line aluminium alloys of excess Si type, and it has Si/ Mg mass ratio is the composition of more than 1, has the age hardening capability of excellence.Therefore, the above-mentioned outer panels of automobile is being rushed When pressing formation, bending machining, utilize low yield strength to guarantee formability.And, dried by the application of the panel after shaping Heating when roasting process etc., relatively low temperature artificial aging (hardening) processes carries out age-hardening, thus yield strength improves, And there is baking application hardening (below, the also referred to as bake hard=BH that may insure that the desirable strength as panel Property, baking hardenability).

On the other hand, it is well known that the above-mentioned outer panels of automobile by aluminium alloy plate is combined carry out stamping swollen Go out when shaping, the forming of bending forming etc. makes.Such as, in the large-scale outer panels of hood and car door etc., logical Cross the stamping of expansion etc., form the formed products shape as outer panels, then, by the flat crimping of this outer panels periphery Deng crimping (hemming) processing, carry out the joint with wainscot, and become panel structure.

Here, 6000 line aluminium alloys have the advantage of the BH possessing excellence, and on the other hand, it has room-temperature aging Property, the room temperature after utilizing solution hardening to process keeps and age-hardening occurs, and makes intensity increase, thus there is the shaping of counter plate Property, the problem that particularly bendability reduces.Such as, when 6000 line aluminium alloy plates are used for car panel purposes, at aluminum Maker, after solution hardening processes (after manufacture), generally at room temperature to be placed before being formed into panel by automobile factory About 1 month (room temperature placement), can occur suitable age-hardening (room-temperature aging) therebetween.Particularly facing harsh bending In the outer panels of processing, even if can form without problems after just manufacturing, add also having crimping after 1 month The problems such as man-hour cracks.Therefore, in 6000 line aluminium alloy plates of car panel use, particularly outer panels, suppression is needed Up to the longer room-temperature aging of about 1 month.

And then, also can produce problems with: in the case of this kind of room-temperature aging is big, BH reduces, and utilizes above-mentioned one-tenth The heating when artificial aging (hardening) of the relatively low temperature of the coating baking process etc. of the panel after shape processes, yield strength is still difficult to Bring up to as the intensity required for panel.

All the time, from the tissue of 6000 line aluminium alloy plates, formed especially with element compound (crystal, Precipitate) from the viewpoint of, the characteristic of the suppression etc. just realizing formability and the raising of BH or room-temperature aging improves and proposes Various technical schemes.Recently, it is also proposed that directly measure BH and the room-temperature aging product especially to 6000 line aluminium alloy plates The trial (patent documentation 1～3) that the cluster (atom set body) of raw impact is controlled.

Wherein, in patent documentation 1, the transmission electron that with this state, the tissue of plate is directly utilized 1,000,000 times is micro- The cluster (atom set body) that BH and room-temperature aging produce impact analyzed by mirror, at viewed cluster (atom set Body) in, the average number density of the cluster of the scope that equivalent diameter is 1～5nm is defined as certain limit, makes BH excellent And inhibit the aluminium alloy plate of room-temperature aging.

To this, in patent documentation 2,3, as patent documentation 1, not directly observe cluster (atom set body), but Utilize three-dimensional atom probe field ion microscope by the position of the atom of the plate of ionizing (electric field evaporation) temporary transient under high electric field Information specifies atom set body defined in the atomic structure by resolving the plate built again.More specifically, under controlling to meet The atom set body of the condition stated: comprise any one in the Mg atom of more than 10 altogether or Si atom or both, and no matter Arbitrary atom in the Mg atom contained using it or Si atom is as benchmark, and it is former with adjacent other to become the atom of this benchmark Monatomic mutual distance of appointing in son is below 0.75nm.I.e., it is stipulated that the average of the atom set body meeting this condition is close Degree, the distribution of size or ratio.

It addition, as to the Sn of the present invention add relevant existing patent, it was also proposed that in a large number at 6000 line aluminium alloys Plate adds Sn energetically and suppresses room-temperature aging, the method improving BH (baking application hardening).Such as, at patent documentation Propose in 4 and have suppression and the BH of room-temperature aging concurrently by adding appropriate Sn and implement preliminary aging after solution treatment The method of property.It addition, propose in patent documentation 5 by add Sn and improve formability Cu and improve formability, BH, The method of corrosion resistance.

Prior art literature

Patent documentation

Patent documentation 1: Japanese Unexamined Patent Publication 2009-242904 publication

Patent documentation 2: Japanese Unexamined Patent Publication 2012-193399 publication

Patent documentation 3: Japanese Unexamined Patent Publication 2013-60627 publication

Patent documentation 4: Japanese Unexamined Patent Publication 09-249950 publication

Patent documentation 5: Japanese Unexamined Patent Publication 10-226894 publication

Summary of the invention

The problem that invention is to be solved

But, even these conventional Al-Mg-Si-type aluminum alloy plates, after taking into account long room-temperature aging Good formability and high BH, still there is room for improvement.

At the aspect of design, the above-mentioned various outer panels of automobile need to realize strainless curved surface attractive in appearance and constitute and special Levy line.Along with being difficult to the employing of the former material of high-strength aluminium alloy plate shaped for lightweight, this kind of requirement becomes tight the most year by year Severe.Therefore, the aluminium alloy plate that formability is more excellent is required the most all the more.But, utilize above-mentioned conventional organizational controls without Method tackles this kind of requirement.

Such as, the reason being difficult to apply high-strength aluminium alloy plate in panel outside as this kind, there is outer panels only The problem of special shape.Utensil or the component such as panel mounting knob seat, lamp socket, license (car plate) seat or partly set outside Put the recess (expanding section, embossed portion) of prescribed depth as describing wheel arch.

This kind of recess is carried out together with the continuous print curved surface around this recess shapes stamping in the case of, easily produce Dough strains, it is difficult to realizes above-mentioned strainless curved surface attractive in appearance and constitutes and feature.Therefore, when the shaping of former material plate must on State the generation that outer panels suppresses this face to strain.

Being explained, the problem of this kind of face strain is not only the problem of above-mentioned recess (expanding section) but also is car door The saddle of outer panels, the longitudinal wall part of front mudguard, the wind corner of rear mudguard, luggage-boot lid or the feature outside hood Disappearance portion, the local such as base portion of installing of rear mud guarding sheet-pile have car panel as the recess (expanding section) that can produce face strain Common problem.

For above-mentioned conventional problem, in order to improve the formability of the generation of above-mentioned of suppression strain, it is desirable to make to strike out 0.2% yield strength of (being room-temperature aging after fabrication) plate during shape is as little as less than 110MPa.But, if so make shaping Time yield strength reduce, then after being difficult to make baking application hardening, the 0.2% of (following, after also referred to as bake hard, after BH) bends Taking intensity is more than 200MPa, and is difficult to make 0.2% yield strength increments based on baking application hardening be more than 100MPa. Above-mentioned conventional organizational controls based on DSC is utilized to be difficult to solve above-mentioned problem.

1st embodiment of the present invention is the embodiment for solving above-mentioned conventional problem, its object is to provide 0.2% yield strength as little as below 110MPa when car panel can be made to shape and 0.2% yield strength after BH can be made Having formability concurrently and toasting the indurative aluminium alloy plate of application (following, the also referred to as the 1st purpose) for more than 200MPa.

It addition, for above-mentioned conventional problem, in order to improve the formability of the generation of above-mentioned of suppression strain, it is desirable to make punching 0.2% yield strength as little as below the 110MPa of (after fabrication for room-temperature aging) plate during pressing formation and make hot strength with Ratio (0.2% yield strength/hot strength) the i.e. yield tensile ratio of yield strength reduces.But, if so make surrender during shaping Intensity reduces, then be difficult to 0.2% yield strength after making baking application hardening (following, also referred to as bake hard, BH) and be More than 190MPa, and be difficult to make 0.2% yield strength increments based on baking application hardening be more than 100MPa.

2nd embodiment of the present invention is the embodiment for solving above-mentioned conventional problem, its object is to provide 0.2% yield strength as little as below 110MPa when car panel can be made to shape and can make yield tensile ratio as little as less than 0.50, And can make 0.2% yield strength after BH is having formability and baking application hardening concurrently and taking into account of more than 190MPa The aluminium alloy plate (following, the also referred to as the 2nd purpose) of high BHization and low yield strength ratio.

For solving the means of problem

Formability and baking application hardening for reaching above-mentioned 1st purpose, the present invention the 1st embodiment are excellent The purport of aluminium alloy plate be: it is not comprise Mg:0.2～2.0%, Si:0.3～2.0%, Sn with the score of quality %: 0.005～0.3% and surplus by Al and Al-Mg-Si-type aluminum alloy plate that inevitably impurity is constituted, at above-mentioned aluminium alloy In the differential scanning calorimeter curve of plate, as being equivalent to the endothermic peak that Mg-Si cluster melts, the temperature model of 150～230 DEG C The peak heights of the endothermic peak enclosed is 8 below μ W/mg (but, including 0 μ W/mg), on the other hand, as being equivalent to Mg-Si cluster The exothermic peak generated, the peak heights of the exothermic peak of the temperature range of 240～255 DEG C is 20 more than μ W/mg.

But, in the differential thermal analysis of each measurement site of above-mentioned aluminium alloy plate, at assay device: Seiko Instruments DSC220G, standard substance: aluminum, sample container: aluminum, Elevated Temperature Conditions: 15 DEG C/min, atmosphere: argon (50ml/min), sample weight: carry out respectively under the identical conditions of 24.5～26.5mg, by the curve of the differential thermal analysis of gained After (μ W) is standardized (μ W/mg) divided by sample weight, in the interval of 0～100 DEG C of above-mentioned differential thermal analysis plots, will The curve of differential thermal analysis is in the region of level and is set to the datum-plane of 0, and measures heat release peak height based on this datum-plane Degree.

It addition, in order to reach above-mentioned 2nd purpose, the formability of the 2nd embodiment of the present invention and baking application hardening The purport of excellent aluminium alloy plate is: its be with the score of quality % do not comprise Mg:0.3～1.0%, Si:0.5～1.5%, Sn:0.005～0.3% and surplus by Al and Al-Mg-Si-type aluminum alloy plate that inevitably impurity is constituted, utilize based on The solid solution capacity of the Mg+Si in the isolated solution of residue extraction of hot phenol is below more than 1.0 mass % and 2.0 mass %,

Further, as the atom set body utilizing three-dimensional atom probe field ion microscope to measure, this atom set body is full Foot is stated: any one or both in the Mg atom comprising more than 10 altogether or Si atom, and the most former with its contained Mg Arbitrary atom in son or Si atom as benchmark, becomes times monatomic with other adjacent atoms of the atom of this benchmark Mutual distance is below 0.75nm, as the cumulative volume of these atom set bodies, according to being distinguished by each atom set body It is considered as discipline Buddhist nun's leaf (Guinier) radius r during ball_GVolume Vi (=4/3 π r of each atom set body calculated_G ³) add and obtain Cumulative volume Σ Vi at the volume V of the above-mentioned aluminium alloy plate utilizing above-mentioned three-dimensional atom probe field ion microscope to measure_AlMiddle institute Average body integration rate (the Σ Vi/V accounted for_Al) × 100 are the scope of 0.3～1.5%, and

In the cumulative volume Σ Vi of above-mentioned atom set body, above-mentioned discipline Buddhist nun leaf radius r_GAtom set for more than 1.5nm The volume V of body_{More than 1.5}The cumulative volume Σ Vi added and obtain_{More than 1.5}Shared average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × 100 be 20～70%.

Invention effect

About above-mentioned 1st embodiment, Sn has the effect that by the tissue of Al-Mg-Si-type aluminum alloy plate Capture atomic vacancy (seizure, trap) in room temperature, thus suppression is in the diffusion of Mg or Si of room temperature, suppress the intensity in room temperature to increase Add, improve the press formabilities such as crimping processability, deep-draw processing, expansion processing when plate is configured to panel (following, also with this punching Pressing formation is referred to as crimping processability for representative).It is additionally, since when the artificial aging such as coating baking process of panel processes Captured hole can be discharged, promote the diffusion of Mg or Si the most on the contrary, BH can be improved.

But, according to the opinion of the present inventor etc., can produce when the interpolation of this kind of Sn and be brought by the distinctive characteristic of Sn New problem.That is, in the case of adding Sn and utilizing conventional method to manufacture plate, according to this manufacturing condition, the interpolation of Sn on the contrary can The Mg-Si cluster contributing to intensity is made to reduce.Therefore, by the interpolation of Sn, and produce and separate out after baking application cure process The amount of precipitate not enough and cannot obtain above-mentioned as the intensity needed for car panel.

Speculate that its reason is as follows, but and uncertain, i.e. the capture of the atomic vacancy of above-mentioned Sn or releasing effect and Sn exist Solid solution capacity in base material is few, and (in conventional method, even if the addition of Sn is suppressed to below theoretical solid solution capacity, it is most of Also not solid solution and with the form crystallization of compound or precipitation) relevant.

In any case, as long as do not solve the side effect that also referred to as this kind Sn add, the Mg-Si group that contributes to intensity Bunch minimizing, the problem such as the precipitate amount that separates out after baking application cure process is not enough, it is likely that make interpolation Sn itself become Nonsensical.

Therefore, in the present embodiment, on the basis of the manufacture method also again examining plate closely, as described later, cause The manufacturing condition of power preliminary aging treatment (reheating process) etc. after solution hardening processes, in order to even if adding Sn, the most not The Mg-Si cluster that can make to contribute to intensity reduces, and will not make the precipitate amount that separates out after baking application cure process not Foot.

And, also know that: though as add Sn also can prevent from contributing to intensity Mg-Si cluster reduce and increase or Guarantee the benchmark of the tissue of the precipitate amount separated out after baking application cure process, the DSC (differential scanning of this plate can be applied Thermal analysis curve).I.e., in the present embodiment, this DSC is utilized to limit the less Mg-Si cluster being equivalent to be helpless to intensity The endothermic peak of fusing, on the other hand, improves and is equivalent to contribute to the exothermic peak that the bigger Mg-Si cluster of intensity generates.Thus, Suppression is helpless to the Mg-Si cluster of intensity, and makes the Mg-Si cluster contributing to intensity increase, thus obtains required BH.

Its result is: according to present embodiment, it is provided that car panel can be made on the basis of with the addition of Sn to shape Time 0.2% yield strength as little as below 110MPa and 0.2% yield strength after BH can be made be having concurrently of more than 200MPa Formability and the baking indurative aluminium alloy plate of application.

It addition, in above-mentioned 2nd embodiment, first, in order to ensure Al-Mg-Si-type aluminum alloy plate in above-mentioned outside Formability on plate (following, the also referred to as crimping processability with this press formability as representative), and when seeking to make this shaping 0.2% yield strength as little as below the 110MPa of plate, and make yield tensile ratio as little as less than 0.50.

Therefore, in the present embodiment, while controlling the alloy composition of Mg, Si etc., also control the solid solution of Mg and Si Amount.It addition, by adding Sn, thus both guaranteed above-mentioned formability, BH is provided again.As described later, Sn has the most important Effect: even if increasing the solid solution capacity of Mg+Si, also will not reduce the volume fraction of the atom set body hindering low yield strength ratio, from And take into account high BHization and low yield strength ratio.

It addition, in the present embodiment, in order to yield tensile ratio when making the shaping of plate further is the most not enough 0.50, in addition to this kind of means, also specify the chi of the atom set body utilizing three-dimensional atom probe field ion microscope to measure Very little distribution is as the control of Mg-Si atom set body.

Here, the atom set body utilizing three-dimensional atom probe field ion microscope to measure described in present embodiment is The known atom set body including the assay method described in above-mentioned patent documentation 2,3, the most as described in Patent Document 1 Utilize powerful TEM with atom collection obtained by the size in the tissue of the direct access panel of state of the tissue of plate, existing forms Fit (cluster).In other words, the details of assay method as shown in the above, as above-mentioned patent documentation 2,3, for utilizing three Dimension atom-probe field ion microscopy to be temporarily ionized under high electric field the plate after (electric field evaporation) atom, by flying Time and location resolution and atom set body under the 3-dimensional atomic structure (Three-dimensional atom mapping) that builds again.And be this three Dimension atomic structure defines (be considered atom set as the atom set body meeting the certain condition of regulation in scheme 1 Body) atom set body.

In the present embodiment, in order to make yield tensile ratio as little as less than 0.50, show as utilizing three-dimensional atom probe field ion The distribution of sizes of atom set body that micro mirror measures, and by above-mentioned meet comprise Mg atom or Si atom and the mutual distance of atom Ratio for the atom set body of the condition of below 0.75nm is limited in certain scope in terms of volume fraction.And, also will Discipline Buddhist nun leaf radius r in these atom set bodies, above-mentioned_GFor the ratio of relatively thick atom aggregation of more than 1.5nm with volume integral Rate meter increases in certain scope.

Its result is: according to present embodiment, it is provided that car panel can be made on the basis of with the addition of Sn to shape Time 0.2% yield strength as little as below 110MPa and can make yield tensile ratio as little as less than 0.50 and after BH 0.2% surrender Intensity is having formability concurrently and toasting the indurative aluminium alloy plate of application of more than 190MPa.

Accompanying drawing explanation

Fig. 1 is the explanatory diagram of the DSC of each example in the embodiment representing the 1st embodiment.

Detailed description of the invention

(the 1st embodiment)

Hereinafter, the 1st embodiment for the present invention is specifically described according to important document.

(chemical composition composition)

First, the chemical composition group to the Al-Mg-Si system of present embodiment (following also referred to as 6000 are) aluminium alloy plate Become to illustrate as follows.To the 6000 line aluminium alloy plates as object of present embodiment owing to requiring as above-mentioned vapour The plates of the outside plate of car etc. and each characteristics such as the formability of excellence, BH, intensity, weldability, corrosion resistance, therefore from composition Aspect is set out these requirements to be met.And, in the present embodiment, by suppressing the room temperature of the plate after manufacturing containing Sn Timeliness, makes 0.2% yield strength as little as below 110MPa during panel forming, improve the panel structure to automobile, especially It it is the formability of the face strain debatable car panel of structure etc..Meanwhile, from the aspect of composition, it is possible to make baking application 0.2% yield strength after hardening is more than 200MPa.

In order to meet this kind of requirement, consisting of of the aluminium alloy plate of present embodiment does not comprise Mg:0.2 with the score of quality % ～2.0%, Si:0.3～2.0%, Sn:0.005～0.3% and surplus are by forming that Al and inevitable impurity are constituted.Give With explanation, the % statement of the content of each element refers to gross mass %.It addition, in the description, the percentage rate on the basis of quality (quality %) is identical with the percentage rate (weight %) on the basis of weight.It addition, about the content of each chemical composition, sometimes will " below X% (but, do not include 0%) " is expressed as " more than 0% and for below X% ".

In the present embodiment, other elements in addition to these Mg, Si, Sn are the element that impurity maybe can comprise, and are Content (allowance) according to each element level of AA or even JIS standard etc..

That is, from the viewpoint of resource reutilization, in the present embodiment, as the melting raw material of alloy, not only can make With high-purity Al ingot, but also can use in a large number and comprise a large amount of other elements in addition to Mg and Si as addition element (alloy Element) 6000 be alloy, other aluminium alloy scraps, low-purity Al ingot etc., now, will necessarily with real mass be mixed into following shown in Other elements.And, the refine itself that have to reduce these elements can make cost increase, needs to allow containing a certain degree of Amount.Even if it addition, contain these elements with real mass, there is also will not hinder the object of the invention and effect containing scope.

Therefore, in the present embodiment, it is allowed to respectively with the upper limit amount of AA or even the JIS standard etc. according to following provisions with Under scope contain this kind of following element.

Specifically, above-mentioned aluminium alloy plate can also comprise choosing with this scope on the basis of above-mentioned basic composition further From below Fe:1.0% (but, do not include 0%), below Mn:1.0% (but, do not include 0%), below Cr:0.3% (but Not include 0%), below Zr:0.3% (but, do not include 0%), below V:0.3% (but, do not include 0%), Ti: Less than 0.1% (but, do not include 0%), below Cu:1.0% (but, do not include 0%), below Ag:0.2% (but, do not wrap Include 0%) and below Zn:1.0% (but, do not include 0%) in one kind or two or more.

It is explained, in the case of containing these elements, if Cu content is many, the most easily makes corrosion resistance be deteriorated, therefore The content of Cu is preferably less than 0.7%, more preferably less than 0.3%.If it addition, the content of Mn, Fe, Cr, Zr, V is many, the most easily Generate thicker compound, and easily make the crimping processability (crimping bendability) becoming problem in present embodiment become Difference.Therefore, Mn content is preferably less than 0.6%, more preferably less than 0.3%, Cr, Zr, V content be respectively preferably 0.2% with Under, more preferably less than 0.1%.

Hereinafter, for each element in above-mentioned 6000 line aluminium alloys containing scope and meaning, or allowance illustrates.

Si:0.3～2.0%

Si be help to when the artificial aging of coating baking process etc. processes together with Si with Mg to improve intensity time Imitate precipitate and play age hardening capability and be used for obtaining as unit necessary to car panel desirable strength (yield strength) Element.If Si addition is very few, then the amount of precipitation after artificial aging becomes very few, causes toasting intensity increments mistake during application Low.On the other hand, if Si content is too much, then form thick crystal with impurity F e etc., make the formabilities such as bendability show Write and reduce.If it addition, Mg content is too much, the intensity after the most just manufacture of plate uprises, and the room-temperature aging amount after manufacturing Also uprise, the intensity before shaping become too high and cause the panel structure to automobile, particularly face strain structure debatable The formability of car panel etc. reduces.Therefore, the content of Si is the scope of 0.3～2.0%.

The timeliness playing excellence for after being configured to panel, more low temperature, coating baking in the short time in processing is hard Change ability, preferably Si/Mg mass ratio is more than 1.0, makes more excessively to contain in Mg compared with general described excessive Si type It is made up of 6000 line aluminium alloys of Si.

Mg:0.2～2.0%

Mg is also similarly with Si for forming the important element of the above-mentioned cluster of regulation in present embodiment, and it is in application The above-mentioned artificial aging such as baking process helps to when processing improve the precipitation of intensity and play timeliness together with Si Hardening capacity and for obtaining as element necessary to the required yield strength of panel.If Mg content is very few, then artificial aging After amount of precipitation become very few, cause toasting the intensity after application too low.On the other hand, if Mg content is too much, then cause with miscellaneous Matter Fe etc. form thick crystal, make the formabilities such as bendability significantly reduce.If it addition, Mg too high levels, the most not only Intensity after the just manufacture of plate uprises, and the room-temperature aging amount after manufacturing also uprises, and the intensity before shaping becomes too high and leads Cause to the panel structure of automobile, the particularly formability of the face strain debatable car panel of structure etc. reduces.Therefore, Mg Content is the scope of 0.2～2.0%.

Sn:0.005～0.3%

Sn has the effect that by capturing atomic vacancy (catch, trap) in room temperature, thus suppression room temperature Mg or The diffusion of Si, suppresses the intensity in room temperature to increase, and when plate is configured to panel, raising crimping processability, deep-draw processing, expansion add The press formabilities such as work (following, the also referred to as crimping processability with this press formability as representative).It is additionally, since at panel The artificial agings such as coating baking process can discharge captured hole when processing, and promotes the diffusion of Mg or Si the most on the contrary, permissible Improve BH.If Sn content is less than 0.005%, then fully cannot capture hole and this effect cannot be played.On the other hand, if Sn Content is more than 0.3%, then, during Sn segregates to crystal boundary, easily become the reason forming grain-boundary crack.It is explained, Sn content excellent The lower limit of choosing is 0.01%.The preferred higher limit of Sn content is 0.2%, is preferably 0.1%, is more preferably 0.06%.

(tissue)

On the basis of above-described composition, in the present embodiment, for the tissue of 6000 line aluminium alloy plates, make For in order to ensure to ensure the amount of the precipitate of precipitation after baking application cure process as the high intensity of car panel etc. Benchmark, control in the DSC of this plate with increase baking application before intensity and baking application time intensity especially relevant, The endothermic peak of specific range of temperatures and exothermic peak.In other words, even if also will not make to contribute to the Mg-Si of intensity to add Sn Cluster reduces and the precipitate amount separated out after baking application cure process will not be made not enough, and uses DSC pair of this plate and increase Intensity when adding the intensity before baking application and baking application especially relevant, in the endothermic peak of specific temperature range and heat release Peak is controlled.

More specifically, in the present embodiment, this DSC is utilized to limit the less Mg-Si being equivalent to be helpless to intensity The endothermic peak of cluster fusing, on the other hand, improves and is equivalent to contribute to the exothermic peak that the bigger Mg-Si cluster of intensity generates.By This, suppression is helpless to the Mg-Si cluster of intensity, and makes the Mg-Si cluster contributing to intensity increase, thus obtains required BH Property.

Here, differential scanning calorimeter curve (DSC) refers to: the fusion processes to the aluminium alloy plate after above-mentioned modifier treatment In thermal change utilize differential thermal analysis based on aftermentioned condition to measure the heating curves from solid phase that obtains.

Specifically, in the differential thermal analysis of each measurement site of above-mentioned aluminium alloy plate, at assay device: Seiko Instruments DSC220G, standard substance: aluminum, sample container: aluminum, Elevated Temperature Conditions: 15 DEG C/min, atmosphere: argon (50ml/min), sample weight: carry out respectively under the identical conditions of 24.5～26.5mg, by the curve of the differential thermal analysis of gained After (μ W) is standardized (μ W/mg) divided by sample weight, in the interval of 0～100 DEG C of above-mentioned differential thermal analysis plots, will The curve of differential thermal analysis is in the region of level and is set to the datum-plane of 0, and measures heat release peak height based on this datum-plane Degree.

In the present embodiment, first, suppression be identified as being helpless to the Mg-Si cluster of intensity, size less and The quantity (number density) of the Mg-Si cluster easily melted in the temperature-rise period of DSC.In BH, if this kind is in the intensification of DSC In journey, easily the quantity of the Mg-Si cluster of fusing increases, even if then carrying out artificial age-hardening's process, is identified as contributing to by force The quantity (number density) of the Mg-Si cluster that degree, size relatively greatly and are difficult to fusing in the temperature-rise period of DSC also can reduce, BH After intensity will not uprise.Specifically, although depend on BH condition, but increase with 0.2% yield strength of more than 100MPa Dosage cannot obtain intensity (0.2% yield strength) after the BH of more than 200MPa.

Therefore, in the present embodiment, as be equivalent to be helpless to intensity, easily melt in the temperature-rise period of DSC The endothermic peak of Mg-Si cluster fusing, suppress to be 8 μ W/mg by the peak heights of endothermic peak A of the temperature ranges of 150～230 DEG C Below (but, including 0 μ W/mg) (low and little).Therefore, the peak heights of the endothermic peak of this temperature range of 150～230 DEG C is 8 μ W/mg represents that the Mg-Si cluster that the size for being helpless to intensity is less is can allow for for the harmful effect of intensity The number density of boundary.From the point of view of the boundary of the manufacture of plate, it is helpless to, there is not this kind, the Mg-Si group that the size of intensity is less Bunch situation (this number density is the situation of 0) under, although be difficult to manufacture, but be included in present embodiment.Therefore, above-mentioned The peak heights of endothermic peak A be 8 below μ W/mg regulation in comprise and there is not this kind and be helpless to the Mg-Si that the size of intensity is less The situation of 0 μ W/mg of cluster.

On the other hand, in the present embodiment, a large amount of generate that to contribute to intensity, size relatively big and in the intensification of DSC Journey is difficult to the Mg-Si cluster of fusing, thus improves BH.Therefore, be equivalent to contribute to what the Mg-Si cluster of intensity generated The peak heights higher (bigger) of exothermic peak B of the temperature range of 240～255 DEG C and be 20 more than μ W/mg.Therefore, this 240～ The peak heights of the exothermic peak of the temperature range of 255 DEG C is that 20 μ W/mg refer to: although depending on BH condition, but, in order to obtain The BH sought in present embodiment improves (the 0.2% yield strength increments of more than 100MPa and the BH of more than 200MPa After 0.2% yield strength), and close shown with the number needed for the bottom line of the larger-size Mg-Si cluster helping intensity Degree.Therefore, this number density is The more the better, and the peak heights the biggest (high) of the exothermic peak of this temperature range of 240～255 DEG C is more Good, if from the point of view of the boundary of the manufacture of plate, its upper limit is 80 μ about W/mg.

In FIG, as embodiment described later, comparative example 25 in example 8 in table 2, comparative example 9, table 33 Plant the DSC of aluminium alloy plate, represent example 8 with thicker solid line, be represented by dotted lines comparative example 9, represent with single dotted broken line and compare Example 25.

In this Fig. 1, in the DSC of comparative example 9, shown in table 2 as be described hereinafter, the heat absorption of the temperature range of 150～230 DEG C The peak heights higher (bigger) of peak A and more than 8 μ W/mg, be helpless to the number density mistake of the less Mg-Si cluster of the size of intensity Many.On the other hand, the peak heights of exothermic peak B of the temperature range of 240～255 DEG C the highest (bigger) and be 20 μ W/mg with On, the number density of the larger-size Mg-Si cluster contributing to intensity is the most.But, due to the above-mentioned size being helpless to intensity The number density of less Mg-Si cluster is too much, and therefore this harmful effect is too strong, it is impossible to obtain target BH (more than 100MPa's 0.2% yield strength after the BH of 0.2% yield strength increments and more than 200MPa).

It addition, in the DSC of the comparative example 25 of Fig. 1, shown in table 2 as be described hereinafter, the suction of the temperature range of 150～230 DEG C The peak heights relatively low (less) of thermal spike A and be 8 below μ W/mg, the number being helpless to the less Mg-Si cluster of the size of intensity is close Spend relatively low.But, on the other hand, the peak heights relatively low (less) of exothermic peak B of the temperature range of 240～255 DEG C and not enough 20 μ W/mg, the number density of the larger-size Mg-Si cluster contributing to intensity is the most very few.Therefore, target cannot still be obtained BH (0.2% yield strength after the 0.2% yield strength increments of more than 100MPa and the BH of more than 200MPa).

On the other hand, in the DSC of the example 8 of Fig. 1, shown in table 2 as be described hereinafter, the temperature range of 150～230 DEG C The peak heights relatively low (less) of endothermic peak A and be 8 below μ W/mg, be helpless to the number of the less Mg-Si cluster of the size of intensity Density is relatively low.And, on the other hand, the peak heights the highest (bigger) of exothermic peak B of the temperature range of 240～255 DEG C and be 20 more than μ W/mg, the number density of the larger-size Mg-Si cluster contributing to intensity is more.Therefore, it is impossible to obtain target BH Property (0.2% yield strength after the 0.2% yield strength increments of more than 100MPa and the BH of more than 200MPa).

(manufacture method)

Then, the manufacture method of the aluminium alloy plate of present embodiment is carried out as follows explanation.The aluminium alloy of present embodiment The manufacturing process of plate itself is conventional method or known method, by closing the aluminum of above-mentioned 6000 set member compositions after casting Gold ingot bar is carried out homogenizing heat treatment, implements hot rolling, cold rolling and become the thickness of slab of regulation, then implements the quenched place of solution hardening etc. Reason manufactures.

But, in these manufacturing processes, in order to obtain the tissue of regulation in the DSC of present embodiment, and as be described hereinafter that Sample, the preliminary aging treatment bar after also making Quenching Treatment on the basis of the average cooling rate of the Quenching Treatment after controlling solid solution Part is preferred scope.It is explained, other operations also have the tissue of regulation in the DSC for obtain present embodiment And preferred condition.If not this kind of preferred condition, then it is difficult to the tissue obtaining specifying in the DSC of present embodiment.

(melting, casting cooling speed)

First, in melting, casting process, suitably select continuous casting process, semi-continuous casting method (DC casting) etc. logical Normal melting and casting method casts and is smelted the molten aluminium alloy being adjusted in above-mentioned 6000 set member compositing ranges.Here, it is excellent Choosing make average cooling rate during casting strengthen as far as possible from liquidus temperature to solidus temperature (quickening) to 30 DEG C/min with On.

If the temperature (rate of cooling) not carrying out such high-temperature area when casting controls, then this high-temperature area Rate of cooling is inevitable slack-off.When the average cooling rate of high-temperature area is slack-off like this, thick in the temperature range of this high-temperature area The quantitative change of the crystal that the earth generates is many, and the plate width direction of ingot bar, the size of crystal of thickness direction and the deviation of amount also become Greatly.Its result is that the basic engineering properties such as the intensity of 6000 line aluminium alloy plates needed for making as premise, percentage elongation reduces.

(homogenize heat treatment)

Then, implemented to homogenize heat treatment before to the aluminium alloy ingot bar hot rolling after above-mentioned casting.At this homogenizing heat-transformation Reason (equal heat treatment) homogenizes with tissue, for the purpose of i.e. eliminating the segregation in the crystal grain in ingot bar tissue.As long as reach this The condition of purpose, then be not particularly limited, and generally can take once or one section of process.

The heat treatment temperature that homogenizes suitably selects less than the scope of fusing point from 500 DEG C, and the time that homogenizes is from 4 Scope more than hour suitably selects.If this homogenization temperature is low, then can not fully eliminate the segregation in crystal grain, its conduct The starting point ruptured works, and therefore stretch flange, bendability reduce.Thereafter, immediately begin to hot rolling or cooling keeps extremely Hot rolling is started again after suitable temperature.

Can also be after carrying out this heat treatment that homogenizes, the coldest with 20～100 DEG C/hr between 300 DEG C～500 DEG C But speed is cooled to room temperature, then, is again heated to 350 DEG C～450 DEG C with the average heating rate of 20～100 DEG C/hr, and This temperature province starts hot rolling.

If deviateing the average cooling rate after this heat treatment that homogenizes and the condition of reheating speed afterwards, then formed thick The probability of big Mg-Si compound uprises, before the effect playing Sn, as 6000 line aluminium alloy plates needed for premise The basic engineering properties such as intensity, percentage elongation is the most decreased.

(hot rolling)

About hot rolling, according to the thickness of slab of rolling, roughing operation and finish to gauge operation by ingot bar (slab) are constituted.Thick at these Roll in operation and finish to gauge operation, suitably use the milling train of reversible or tandem etc..

At this moment, under conditions of hot rolling (roughing) beginning temperature exceedes solidus temperature, it may occur that burning, therefore hot rolling is originally Body is difficult to.It addition, when hot rolling starts temperature less than 350 DEG C, load during hot rolling is too high, and hot rolling is difficult to itself. Therefore, hot rolling starts temperature and is preferably 350 DEG C～solidus temperature, more preferably 400 DEG C～the scope of solidus temperature.

(annealing of hot rolled plate)

The cold rolling front annealing (black annealing) of this hot rolled plate is not necessarily required to, but in order to charge-coupled by the miniaturization of crystal grain and collection Suitableization knitted and the characteristic making formability etc. improves further, it is also possible to implement.

(cold rolling)

In cold rolling, roll above-mentioned hot rolled plate, be fabricated to the cold-reduced sheet (also including coiled material) of desired final thickness of slab.But It is, in order to make the further miniaturization of crystal grain, it is desirable to no matter why road number of times makes total cold rolling rate is more than 60%.

(solid solution and Quenching Treatment)

Solution treatment is carried out and ensuing until the Quenching Treatment of room temperature after cold rolling.About this solution treatment, Ke Yiyou Common continuous heat-treatment lines carries out heating, cooling down, and is not particularly limited.But, owing to expectation obtains the sufficient of each element Solid solution capacity and make crystal grain finer as described above, it is desirable to be heated to 520 DEG C with the firing rate of more than 5 DEG C/sec Solid solution temperature above and below melt temperature is carried out under conditions of keeping 0.1～10 second.

It addition, from the viewpoint of the thick crystal boundary compound formation that suppression makes formability and crimping processability reduce, Preferably the average cooling rate from the quenching stopping temperature of solid solubility temperature to room temperature is 3 DEG C/more than s.If straight after solution treatment Less to the rate of cooling of Quenching Treatment of room temperature, then cause in cooling, generate thick Mg-Si and simple substance Si, and cause Formability is deteriorated.It addition, the solid solution capacity after solutionizing reduces, BH is caused to reduce.In order to ensure this rate of cooling, until room temperature Quenching Treatment select to use the air of fan etc. to cool down respectively, spray, spray water, the magnetism servo-electric motor water-cooling of impregnating and condition.

(preliminary aging treatment: reheating processes)

After carrying out Quenching Treatment after this kind of solution treatment and being cooled to room temperature, within 1 hour, cold-reduced sheet is carried out pre- Standby Ageing Treatment (reheating process).If until the Quenching Treatment of room temperature terminates afterwards and preliminary aging treatment starts (heating starts) Room temperature i time before is long, then cause generating the above-mentioned less Mg-Si cluster of intensity that is helpless in a large number as because of room temperature Timeliness and the cluster that easily melts, it is difficult to the peak heights of the endothermic peak of the temperature ranges of 150～230 DEG C is suppressed 8 μ W/mg with Under.Therefore, this room temperature i time is the shortest more good, solid solution and Quenching Treatment and reheating process can also take almost without The mode of time difference is carried out continuously, and the time of lower limit sets the most especially.

In this preliminary aging treatment, control until the programming rate of preliminary aging temperature and in preliminary aging temperature range Retention time.Wherein, in order to suppress the generation of the above-mentioned less Mg-Si cluster being helpless to intensity, programming rate preferably sets It it is the biggest (fast) programming rate of 1 DEG C/more than s, preferably 5 DEG C/more than s.If programming rate is less than 1 DEG C/s, then lead Cause Mg-Si cluster that a large amount of generation is helpless to intensity, that easily melt in the temperature-rise period of DSC, it is difficult to by 150～230 DEG C Temperature range endothermic peak peak heights suppress at 8 below μ W/mg.

It addition, the temperature of preliminary aging treatment and retention time are temperature range holding more than the 10hr at 60～120 DEG C And below 40hr.At this point it is possible to by these 60～120 DEG C temperature keep being set to keep certain temperature in this temperature range Or the heat treatment of temperature is changed successively by intensification, slow cool down.In a word, temperature is carried out continuously even with slow cool down or intensification etc. Degree change, as long as the temperature province at 60～120 DEG C keeps above-mentioned more than 10hr and below 40hr.

If preliminary aging temperature is less than 60 DEG C or the retention time is less than 10hr, then the generation separating out core is insufficient, at DSC In, the peak temperature of the exothermic peak in the range of exothermic peak B of the temperature range of 240～255 DEG C easily becomes higher than 255 DEG C Temperature.This means that the larger-size Mg-Si cluster contributing to intensity reduces, it is impossible to make the temperature model of 240～255 DEG C The peak heights higher (bigger) of exothermic peak B enclosed and be 20 more than μ W/mg.Its result makes BH reduce.

On the other hand, if more than 120 DEG C or the retention time is more than 40hr, then in this preliminary aging treatment for preliminary aging temperature In separate out core growing amount excessively increase.Therefore, the larger-size Mg-Si cluster contributing to intensity is made to reduce on the contrary, nothing Method makes the peak heights of exothermic peak B of the temperature range of 240～255 DEG C in DSC be up to (arriving greatly) 20 more than μ W/mg, and BH is still Can reduce.And, intensity during shaping also becomes too high.

That is, if not making preliminary aging treatment be in these preferred condition and ranges, then when being difficult to make car panel shape 0.2% yield strength as little as below 110MPa, and to be difficult to 0.2% yield strength after making BH be more than 200MPa.

Hereinafter, the 2nd embodiment for the present invention is specifically described according to important document.

(chemical composition composition)

First, the chemical composition group to the Al-Mg-Si system of present embodiment (following also referred to as 6000 are) aluminium alloy plate Become to illustrate as follows.The 6000 line aluminium alloy plates as object of present embodiment are required as above-mentioned automobile The plates of outside plate etc. and each characteristics such as the formability of excellence, BH, intensity, weldability, corrosion resistance, therefore in terms of composition Set out these requirements to be met.And, in the present embodiment, during by suppressing the room temperature of plate after manufacturing containing Sn Effect, makes 0.2% yield strength as little as below 110MPa during panel forming, and makes yield tensile ratio as little as less than 0.50, thus carry The high panel structure to automobile, the particularly face strain debatable car panel of structure etc. formability.Meanwhile, from group The aspect become is set out, it is possible to making 0.2% yield strength after baking application hardening is more than 190MPa.

In order to meet this kind of requirement, consisting of of the aluminium alloy plate of present embodiment does not comprise Mg:0.3 with the score of quality % ～1.0%, Si:0.5～1.5%, Sn:0.005～0.3% and surplus are by forming that Al and inevitable impurity are constituted.Give With explanation, the statement % of the content of each element refers to gross mass %.It addition, in the description, the percentage rate on the basis of quality (quality %) is identical with the percentage rate (weight %) on the basis of weight.It addition, about the content of each chemical composition, sometimes will " below X% (but, do not include 0%) " is expressed as " more than 0% and for below X% ".

That is, according to the reason as above-mentioned 1st embodiment, in the present embodiment, it is allowed to respectively with according to following Scope below the upper limit amount of AA or even the JIS standard etc. of regulation contains this kind of other elements as described below.

Specifically, above-mentioned aluminium alloy plate can also comprise choosing with this scope on the basis of above-mentioned basic composition further From below Fe:1.0% (but, do not include 0%), below Mn:0.4% (but, do not include 0%), below Cr:0.3% (but Not include 0%), below Zr:0.3% (but, do not include 0%), below V:0.3% (but, do not include 0%), Ti: Less than 0.1% (but, do not include 0%), below Cu:0.4% (but, do not include 0%), below Ag:0.2% (but, do not wrap Include 0%) and below Zn:1.0% (but, do not include 0%) in one kind or two or more.

It is explained, in the case of containing these elements, if Cu content is many, the most easily makes corrosion resistance be deteriorated, therefore The content of Cu is preferably less than 0.3%.If it addition, the content of Mn, Fe, Cr, Zr, V is many, then easily generate thicker chemical combination Thing, and easily make the crimping processability (crimping bendability) becoming problem in present embodiment be deteriorated.Therefore, Mn content is preferred Being less than 0.35%, Cr, Zr, V content are respectively preferably less than 0.2%, more preferably less than 0.1%.

Si:0.5～1.5%

Si be help to when the artificial aging of coating baking process etc. processes together with Si with Mg to improve intensity time Imitate precipitate and play age hardening capability and be used for obtaining as unit necessary to car panel desirable strength (yield strength) Element.It addition, solid solution Si is the element improving work hardening capacity, it has makes hot strength strong with surrender by carrying out solid solution Ratio (0.2% yield strength/hot strength) the i.e. yield tensile ratio of degree is reduced to the effect less than 0.50.

If Si content is very few, then the precipitate quantitative change after artificial age-hardening processes obtains very few, intensity during baking application Increments step-down, and solid solution Si amount also tail off, cause yield tensile ratio become excessive and more than 0.50.On the other hand, if Si content Too much, then form thick crystal with impurity F e etc., make the formabilities such as bendability significantly reduce.If it addition, Mg content Too much, the intensity after the most just manufacture of plate uprises, and the room-temperature aging amount after manufacturing also uprises, and the intensity before shaping becomes Too high and cause the formability fall panel structure to automobile, the particularly face strain debatable car panel of structure etc. Low.Therefore, the content of Si is the scope of 0.5～1.5%.

Mg:0.3～1.0%

Mg is also similarly with Si for forming the important element of the above-mentioned atom set body of regulation in present embodiment, and it is Help to together with Si when the above-mentioned artificial agings such as coating baking process process improve the precipitation of intensity and send out Wave age hardening capability and for obtaining as element necessary to the required yield strength of panel.It addition, as Si, Gu Molten Mg is the element improving work hardening capacity, and it has makes the ratio of hot strength and yield strength by carrying out solid solution (0.2% yield strength/hot strength) i.e. yield tensile ratio is reduced to the effect less than 0.50.

If Mg content is very few, then the precipitate quantitative change after artificial age-hardening processes obtains very few, intensity during baking application Increments step-down, and solid solution Mg amount also tail off, cause yield tensile ratio become excessive and more than 0.50.On the other hand, if Mg content Too much, then cause forming thick crystal with impurity F e etc., make the formabilities such as bendability significantly reduce.If it addition, Mg Too high levels, the most not only the intensity after just the manufacturing of plate uprises, and the room-temperature aging amount after manufacturing also uprises, strong before shaping Degree becomes too high and causes the formability panel structure to automobile, the particularly face strain debatable car panel of structure etc. Reduce.Therefore, the content of Mg is the scope of 0.3～1.0%.

Sn:0.005～0.3%

Sn has following important result: even if increasing the solid solution capacity of Mg+Si described later, also can reduce when making panel forming The volume fraction of the atom set body that 0.2% yield strength increases, thus have high BHization and low yield strength ratio concurrently.General and Speech, in order to increase the solid solution capacity of Mg+Si, effectively makes Mg or Si contained in plate increase.But, if increasing these Mg or Si Content in plate, then make 0.2% yield strength during panel forming increase, and causes the atom set hindering low yield strength ratio The volume fraction of body also increases, and is difficult to take into account high BHization, low yield strength and low hence with conventional composition and preparation method Yield tensile ratio.On the other hand, present embodiment is by containing Sn with above-mentioned scope, thus increases the solid solution capacity of Mg+Si and improve BH, nonetheless, also can suppress to hinder the atom set body of low yield strength ratio, it is possible to take into account high BHization, low yield strength Change and low yield strength ratio.

It addition, Sn has the effect that by capturing atomic vacancy (seizure, trap) in room temperature, thus suppression is in room temperature The diffusion of Mg or Si, suppress the intensity in room temperature to increase (room-temperature aging hardening), when plate is configured to panel, raising crimping adds The press formabilities such as work, deep-draw processing, expansion processing (following, the also referred to as crimping processing with this press formability as representative Property).It is additionally, since and can discharge captured hole, the most on the contrary when the artificial aging such as coating baking process of panel processes Promote the diffusion of Mg or Si, BH can be improved.

If Sn content is less than 0.005%, even if then increasing the solid solution capacity of above-mentioned Mg+Si, obstruction also can be reduced low in the wrong strong The volume fraction of the atom set body of ratioization, it is impossible to play and take into account high BHization and the effect of low yield strength ratio, above-mentioned room temperature The inhibition of age-hardening.On the other hand, if Sn content is more than 0.3%, then during Sn segregates to crystal boundary, easily become formation crystalline substance The reason of limiting fissure stricture of vagina.Being explained, the preferred lower limit of Sn content is 0.01%.The preferred higher limit of Sn content is 0.2%, 0.1%, more preferably 0.06% it is preferably.

(solid solution capacity of Mg+Si)

On the basis of above-described composition, in the present embodiment, in order to improve BH, and plate institute is increased further Total solid solution capacity (solid solution capacity of Mg+Si) of Mg and Si contained, and make it guarantee more than 1.0 mass % and 2.0 mass % with Under certain scope in.If the solid solution capacity of Mg+Si is less than 1.0 mass %, even if being then above-mentioned composition, BH also cannot be guaranteed Property.The solid solution capacity of this Mg+Si is the most, and BH more improves, but Mg, Si, content and solid solution capacity are also by above-mentioned composition and system The restriction made, and, if solid solution capacity is too much, then there is also the volume fraction increase of above-mentioned atom set body, panel forming Time yield strength and yield tensile ratio become big problem, therefore the upper limit is 2.0 mass %.

About the mensuration of solid solution capacity of the Mg+Si of plate, utilize residue extraction based on hot phenol to become and measure object The sample fusing of plate, utilizes the filter making net be 0.1 μm that solid-liquid carries out filtering separation, and the Mg in the solution that will be separated With the solid solution capacity that the total content of Si is considered as Mg+Si.

Residue extraction based on hot phenol is carried out the most in such a way.First, in decomposing flask, add phenol to enter After row heating, using respectively moving in this decomposition flask for test plate (panel) sample as measure object, carry out heat resolve.Then, add After benzylalcohol, utilize above-mentioned filter to carry out suction strainer, carry out solid-liquid filtering separation, and to Mg's and Si in the solution separated Total content carries out quantitative analysis.Atomic absorption analysis method (AAS), inductively coupled plasma is suitably used in this quantitative analysis Luminescence analysis (ICPOES) etc..Using net (trapping particle diameter) as described above in above-mentioned suction strainer is 0.1 μm and φ 47mm Membrane filter.About this mensuration and calculating, to 1 position of central part from the plate width for test plate (panel) with from this central part 3 each samples extracted at 3 positions that amount at 2 positions, both ends of plate width are carried out, and by the Mg+Si of this each sample Solid solution capacity (quality %) equalization.

(atom set body)

On the basis of above-described composition, tissue, in the present embodiment, for the group of 6000 line aluminium alloy plates Knit, in order to make yield tensile ratio as little as less than 0.50 and also ensure BH, micro-to utilizing three-dimensional atom probe field ion further The distribution of sizes of the atom set body of Mg and Si that mirror measures is controlled.Thus, not only there is the effect of above-mentioned Sn, and High BHization and low yield strength ratio is also taken into account by the atom set body (cluster) in the tissue of panel.

(definition of atom set body)

But, as shown in the record on effect one hurdle, in the present embodiment, will utilize based on three-dimensional atom probe field ion Mensuration and the parsing of microscopical principle and meet the atom set body of several conditions (important document) of defined and be defined as atom collection Fit.That is, utilizing three-dimensional atom probe field ion microscope to the plate of ionizing (electric field evaporation) temporary transient under high electric field Atom, carried out resolving by flight time and position and in the 3-dimensional atomic structure (Three-dimensional atom reflection) that builds again, by satisfied basis In embodiment, the atom set body of several conditions (important document) of regulation is defined as atom set body.

Therefore, as described in Patent Document 1, the atom set body specified in the present embodiment non-used high magnification TEM (infiltration type ultramicroscope) plate is organized the reality in the 6000 line aluminium alloy plates directly observed with this state and measure The atom set body (cluster) that border exists.But, and in the 6000 line aluminium alloy plates utilizing above-mentioned powerful TEM directly to observe The existence of in esse atom set body (cluster) closely related.Accordingly, with respect to the atom collection in present embodiment Fit mensuration, even if also producing low yield strength ratio or high BHization with in so-called indirect measures or simulation measures The existing forms of these the in esse atom set bodies (cluster) significantly affected is closely related, becomes from tissue (atom collection Fit) aspect set out guarantee low yield strength ratio and the benchmark of high BHization.

Here, the plate becoming mensuration object is to implement the quenched rear of solution treatment and Quenching Treatment etc. and carry out stamping Or 6000 line aluminium alloy plates before baking application cure process, and utilize three-dimensional atom probe field ion microscope to this plate The arbitrarily tissue of thickness of slab central part is measured.

(condition that should meet as atom set body)

Hereinafter the condition (precondition) being defined as (being considered as) atom set body in present embodiment is illustrated.

The condition that should meet as the atom set body in present embodiment is identical with above-mentioned patent documentation 2,3.First, for Comprise any one in the Mg atom of more than 10 altogether or Si atom or both atom set bodies.It is explained, this atom Mg atom, the upper limit of the number of Si atom not specially provided for contained in aggregation, but, if from the point of view of manufacturing boundary, then Mg atom contained in this atom set body or the upper limit substantially about 10000 of the number of Si atom.

And, also by no matter using contained Mg atom in these atom set bodies or any one atom in Si atom as Benchmark and become the atom of this benchmark and equal below the 0.75nm's of mutual distance of any one atom in other adjacent atoms Atom set body is set to atom set body.The art-recognized meanings of this mutual distance 0.75nm is the clearest and the most definite, may be Mg or Si Mutual interatomic distance close to and low yield strength ratio and high BHization are produced the atom set of the size significantly affected Body or specify this volume fraction well for repeatability and the value that experimentally determines.

For the atom set body of regulation in present embodiment, although comprise the situation of Mg atom and Si atom Many, but also include comprising Mg atom but do not comprise the situation of Si atom, comprise Si atom but do not comprise the situation of Mg atom.Separately Outward, it is not limited to only by Mg atom, Si atomic building, it is also possible on this basis with the highest probability packet atom Han Al.

And then, be grouped into according to the one-tenth of aluminium alloy plate, the Fe that comprises as alloying element or impurity, Mn, Cu, Cr, Zr, The atoms such as V, Ti, Zn or Ag are included in atom set body, necessarily lead to utilize 3DAP to analyze and count these other atoms The situation of number.But, these other atoms (from alloying element, impurity) even if being included in atom set body, if former with Mg It is also little level that son is compared with the sum of Si atom.Therefore, even if comprising other atoms in atom set body at this kind In the case of, meet the atom set body of above-mentioned regulation (condition) also can play as the atom set body of present embodiment with Only by the function that the atom set body of Mg atom, Si atomic building is same.Therefore, the atom set body of regulation in present embodiment As long as meeting above-mentioned regulation, then can also comprise other arbitrary atoms.

It addition, present embodiment " no matter using the arbitrary atom in its contained Mg atom or Si atom as benchmark Become the atom of this benchmark and be below 0.75nm with the monatomic mutual distance of appointing in other adjacent atoms " refer to: former It is below 0.75nm's that whole Mg atoms present in subset zoarium, Si atom at least have 1 in the most mutual distance Mg atom, Si atom.

About in the atom set body of present embodiment, the regulation of atom distance each other, no matter with its contained Mg Arbitrary atom in atom or Si atom, as benchmark, becomes atom and the whole atoms in other adjacent atoms of this benchmark Distance all can distinguish all below 0.75nm, on the contrary, it is also possible to respectively all below 0.75nm.In other words, The distance other the Mg atom more than 0.75nm, Si atom can be adjacent, former at specific (on the basis of one-tenth) Mg atom or Si As long as there are minimum 1 other Mg atom meeting this predetermined distance (interval) or Si atom in the surrounding of son.

And, in the case of there is 1 other adjacent Mg atom meeting this predetermined distance or Si atom, meet away from From condition, should the quantity of calculated Mg atom or Si atom comprise specifically (on the basis of one-tenth) Mg atom or Si atom exist It is inside 2.It addition, in the case of there is 2 other adjacent Mg atoms meeting this predetermined distance or Si atom, meet away from Specifically Mg atom or Si atom (on the basis of one-tenth) is comprised from condition, the Mg atom that should be counted or Si atom number It it is 3.

(control of atom set body)

First, in the present embodiment, Mg atom, the number of Si atom and interatomic distance are met as described above Deng the cumulative volume of the atom set body of certain condition, try to achieve by discipline Buddhist nun's leaf radius when each atom set body is respectively seen as ball r_GVolume Vi (=4/3 π r of each atom set body calculated_G ³) the cumulative volume Σ Vi that adds and obtain.Then, this is overall Long-pending Σ Vi is at the volume V of the above-mentioned aluminium alloy plate utilizing above-mentioned three-dimensional atom probe field ion microscope to measure_AlPutting down shared by All bodies divide rate (Σ Vi/V_Al) × 100 control is the scope of 0.3～1.5%.

And then, in the present embodiment, in addition to controlling the volume fraction of above-mentioned atom set body, also will satisfied on State above-mentioned discipline Buddhist nun leaf radius r in cumulative volume Σ Vi in the atom set body of condition, above-mentioned atom set body_GFor 1.5nm with On the cumulative volume Σ Vi of atom set body_{More than 1.5}Shared average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) control 20～70% Scope.That is, each atom set body of above-mentioned condition will be met according to discipline Buddhist nun leaf radius r_G1.5nm divides, and will record Buddhist nun leaf radius r_GVolume Vi for each atom set body of more than 1.5nm_{More than 1.5}The cumulative volume Σ Vi added and obtain_{More than 1.5}Upper State average body integration rate (Σ Vi shared in the cumulative volume V of atom set body_{More than 1.5}/ Σ Vi) × 100 control 20～70% Scope.

Here, it addition, discipline Buddhist nun's leaf radius (Guinier radius) r_GFor: the atom set body of above-mentioned condition will be met , time each atom set body is respectively seen as ball, radius of turn l that each atom set body is had_gThe half of middle maximum Footpath is set to radius of turn l of this atom set body_g, and by this radius of turn l_gUtilize the radius that formula described later converts.And, Definition and the computational methods described later of this discipline Buddhist nun's leaf radius are known because of above-mentioned patent documentation 2,3.

Utilizing these organizational controls, the control with above-mentioned composition is combined, and makes the car panel of 6000 line aluminium alloy plates become 0.2% yield strength as little as below 110MPa during shape, and make yield tensile ratio as little as less than 0.50, BH can be made on this basis After 0.2% yield strength be more than 190MPa.

Above-mentioned average body integration rate (Σ Vi/V at the atom set body meeting above-mentioned condition_Al) × 100 are less than 0.3% Time, to high BHization or low yield strength ratioization effectively discipline Buddhist nun leaf radius r_GRelatively thick atom aggregation absolute for more than 1.5nm Number deficiency.Therefore, even if meeting above-mentioned composition, above-mentioned high BHization and low yield strength ratio cannot also be reached.On the other hand, even if Above-mentioned average body integration rate (Σ Vi/V_Al) × 100 are more than 1.5%, and meeting the mutual distance with above-mentioned atom is below 0.75nm Too much etc. the quantity of the atom set body of condition, it is impossible to the reduction of 0.2% yield strength when realizing panel forming and low bend strong Ratioization.

Even if it addition, to high BHization or low yield strength ratioization effectively discipline Buddhist nun leaf radius r_GBigger for more than 1.5nm Average body integration rate (the Σ Vi of atom set body_{More than 1.5}/ Σ Vi) × 100 less than 20%, the absolute number of these atom set bodies is also Deficiency, even if the average body integration rate meeting above-mentioned composition and the atom set body that meets above-mentioned condition meets above-mentioned regulation, also Low yield strength ratio cannot be reached.On the other hand, discipline Buddhist nun leaf radius r_GFor more than 1.5nm bigger atom set body number and Ratio is the most, more can realize low yield strength ratio, is difficult to make average body integration rate (Σ Vi on manufacturing_{More than 1.5}/ Σ Vi) × 100 increasings Big and more than 70%, from the point of view of manufacturing boundary, with this 70% as the upper limit.

(measuring principle of 3DAP and assay method)

The measuring principle of 3DAP and assay method are also known because of above-mentioned patent documentation 1～3.That is, 3DAP (visit by Three-dimensional atom Pin) it is the device being provided with time-of-flight type mass analyzer on field ion microscope (FIM).It is: based on such structure Become, utilize field ion microscope to observe each atom of metal surface, and analyzed by time of flight mass, it is possible to be former to these Son carries out the partial analysis device identified.It addition, because 3DAP can analyze kind and the position of the atom from sample release simultaneously Put, so being very effective means in the structural analysis of atom set body.Therefore, as described above as known technology In fabric analysis for magnetic recording film, electronic device or steel etc..It addition, recently, the most also use at aluminium alloy In the differentiation of the atom set body of the tissue of plate etc..

In this 3DAP, the ionizing of the sample atom under the high electric field being known as field evaporation of utilization itself is existing As.If the high voltage required for sample atom is used for field evaporation puts on sample, then from specimen surface, atom is by ion Changing, it arrives detector by inspecting hole.

This detector is position sensing type detector, carries out the quality analysis (element as atomic species of each ion Qualification), and measure each ion arrive detector flight time, it is possible to determine that the position of this detection is (former simultaneously Minor structure position).Therefore, 3DAP can measure position and the atomic species of the atom of sample front end simultaneously, and therefore, having can Dimensionally reconstruct, observe the speciality of the atomic structure of sample front end.It addition, field evaporation is sent out successively from the front end face of sample Raw, therefore, it is possible to investigate the depth direction distribution of the atom from sample front end with the resolution of atom level.

Owing to this 3DAP utilizes high electric field, so the sample analyzed needs to be the sample that the electric conductivity such as metal are high, and, examination The shape of sample is it is generally required to be the point diameter superfine needle-like at 100nm about φ or thinner.Therefore, from as measuring object The thickness of slab central part etc. of aluminium alloy plate take sample, this sample is carried out cutting and electrolytic polishing with precision cutting device, Make the sample with the superfine needle-like leading section analyzed.As assay method, carry out the most as follows: use " LEAP3000 " of the Imago Scientific Instruments company aluminium alloy plate to its front end being configured to needle-like Sample applies the high pulse voltage of 1kV level, makes millions of atom ionizings constantly from sample front end.Ion utilizes position Sensitive detector detects, and applies pulse voltage, and each ion is after sample front end flies out, according to until arriving detector Flight time, carry out the quality analysis (as the qualification of element of atomic species) of ion.

Additionally, field evaporation utilizes the character that the front end face from sample occurs the most regularly, in the arrival representing ion Place, the coordinate that provides Suitable depth direction in two-dimensional map, use and analyze software " IVAS " and carry out three-dimensional mapping (under three-dimensional Atomic structure: the structure of atom map).Thus, the Three-dimensional atom reflection of sample front end is obtained.

This Three-dimensional atom is videoed, also uses the method belonging to precipitate, the atom of atom set body is defined I.e. Maximum Separation Method, carries out the parsing of atom set body (atom set body).When this parsing, it is provided that The quantity (more than 10 altogether) of any one or both in Mg atom or Si atom and the most adjacent Mg atom or Si atom Distance (interval) each other and the above-mentioned Mg atom with specific narrow intervals (below 0.75nm) or the quantity of Si atom As parameter.

And, by meet amount to containing any one in the Mg atom of more than 10 or Si atom or both and no matter It is former with adjacent other that arbitrary atom in the Mg atom contained using it or Si atom becomes the atom of this benchmark as benchmark The atom set body of these conditions that the monatomic mutual distance in son is below 0.75nm is defined as present embodiment Atom set body.And, the dispersity of the atom set body meeting this definition is evaluated, with more than 3 mensuration The number density of atom set body is averaged by sample number, and according to every 1m³Average density (individual/m³) measure, quantitatively Change.

That is, utilize above-mentioned 3DAP proper analysis software inherently, try to achieve as mensuration according to the following formula of several 1 The above-mentioned atom set of object is stereoscopic for maximum radius of turn l during ball_g。

[several 1]

l_{g} = \sqrt{\frac{Σ_{i = 1}^{n} [{(x_{i} - \overset{&OverBar;}{x})}^{2} + {(y_{i} - \overset{&OverBar;}{y})}^{2} + {(z_{i} - \overset{&OverBar;}{z})}^{2}]}{n}}

In this formula of several 1, l_gFor utilizing the intrinsic software of three-dimensional atom probe field ion microscope automatically to calculate The radius of turn gone out.X, y, z is x, y, z axle constant in the mensuration layout of three-dimensional atom probe field ion microscope.x_i、y_i、 z_iFor the length of this x, y, z axle, it is the space coordinates of Mg, Si atom constituting above-mentioned atom set body.At " x ", " y ", " z " Upper respectively plus "-"Deng being also the length of this x, y, z axle, but it is the barycentric coodinates of above-mentioned atom set body.N is Constitute the quantity of Mg, Si atom of above-mentioned atom set body.

Then, radius of turn l each atom set body being had_gThe radius of middle maximum is set to this atom set body Radius of turn l_g, and according to the following formula of several 2, r_G=√ (5/3) l_gRelation be scaled discipline Buddhist nun leaf radius r_G.And, will The discipline Buddhist nun leaf radius r of this conversion_GIt is considered as the radius of atom set body.

[several 2]

r_{G} = \sqrt{\frac{5}{3}} \cdot l_{g}

Based on case above, volume Vi (=4/3 π r of each atom set body of above-mentioned condition will be met_G ³) add and and ask Obtain cumulative volume Σ Vi.And, the volume of (disappearing because of electric field evaporation) the needle-like sample evaporated by above-mentioned electric field is set to utilize The volume V of the aluminium alloy plate that three-dimensional atom probe field ion microscope measures_Al, and try to achieve at this volume V_AlIn shared above-mentioned Average body integration rate (the Σ Vi/V of the cumulative volume of atom set body_Al)×100.It addition, also try to achieve at above-mentioned atom set body Discipline Buddhist nun leaf radius r shared in cumulative volume V_GCumulative volume Σ Vi for the atom set body of more than 1.5nm_{More than 1.5}Average external volume Divide rate (Σ Vi_{More than 1.5}/ΣVi)×100.About the mensuration of the average body integration rate of these atom set bodies based on 3DAP, right Implement above-mentioned quenched after any 10 positions of thickness of slab central part of 6000 line aluminium alloy plates carry out, and by these above-mentioned each surveys Definite value (value of calculation) averages.

The calculating formula of the radius of above-mentioned atom set body, from radius of turn l_gTo discipline Buddhist nun leaf radius r_GMensuration and conversion Method refer to M.K.Miller:Atom Probe Tomography, (Kluwer Academic/Plenum Publishers, New York, 2000), page 184.By the way, the calculating formula of the radius of atom set body is in addition also It is documented in substantial amounts of document.Such as in " microstructure change of the low-alloy steel of ion exposure ", (a rattan well gram man of virtue and ability, good fortune paddy are ploughed Department, big Kubo are loyal, precious wild and rich etc.) page 140 " (2) three-dimensional atom probe analyses " in describe above-mentioned several 1 with containing Formula, to discipline Buddhist nun leaf radius r_GConversion formula (wherein, radius of turn l_gSymbol be recited as r_G)。

(atom detection efficiency based on 3DAP)

At present, the detection efficiency of these atoms based on 3DAP with about 50% in the atom of ionizing as boundary, its Remaining atom can not detect.For the detection efficiency of this atom based on 3DAP, send out if increasing in the future etc. Life significantly changes, then the mean number density (individual/μm of the atom set body of each size of present embodiment regulation³) based on There is the probability of variation in the measurement result of 3DAP.Therefore, in order to make this mensuration have repeatability, the inspection of atom based on 3DAP Survey the preferred constant of efficiency and about 50%.

(manufacture method)

But, in these manufacturing processes, in order to obtain in the 3DAP of present embodiment the groups such as the atom set body of regulation Knit, and as described later, pre-after making Quenching Treatment on the basis of the average cooling rate of the Quenching Treatment after controlling solid solution Standby Ageing conditions is preferred scope.It is explained, also has in other operations for obtaining rule in present embodiment Fixed tissue and preferred condition.If not this kind of preferred condition, then it is difficult to obtain the tissue of present embodiment.

(melting, casting cooling speed)

If the temperature (rate of cooling) not carrying out such high-temperature area when casting controls, then this high-temperature area Rate of cooling is inevitable slack-off.When the average cooling rate of high-temperature area is slack-off like this, thick in the temperature range of this high-temperature area The quantitative change of the crystal that the earth generates is many, and the plate width direction of ingot bar, the size of crystal of thickness direction and the deviation of amount also become Greatly, the basic engineering properties such as the intensity of 6000 line aluminium alloy plates needed for making as premise, percentage elongation reduces.

(heat treatment that homogenizes, hot rolling, the annealing of hot rolled plate, cold rolling and solid solution and Quenching Treatment)

Then, in the same manner as the situation of above-mentioned 1st embodiment, the aluminium alloy cast ingot of above-mentioned casting is implemented homogenizing heat-transformation Process, hot rolling, each of annealing, cold rolling and solid solution and Quenching Treatment of (carrying out as required) hot rolled plate process.Said Bright, owing to these each conditions respectively processed are as above-mentioned 1st embodiment, therefore omit its description at this.

(preliminary aging treatment: reheating processes)

After carrying out Quenching Treatment after this kind of solution treatment and being cooled to room temperature, to the greatest extent may be used within 1 hour (60 minutes) In time that can be short, cold-reduced sheet is carried out preliminary aging treatment (reheating process).

If until the Quenching Treatment of room temperature terminates afterwards and preliminary aging treatment starts the room temperature before (heating starts) and keeps Overlong time and more than 1 hour, then cannot former by the above-mentioned condition meeting Mg atom, the number of Si atom, interatomic distance The cumulative volume of subset zoarium is limited to less than 1.5% in terms of average body integration rate.It addition, simultaneously, be also difficult to generate bigger group Bunch, and discipline Buddhist nun leaf radius r in the atom set body meet above-mentioned condition cannot be made_GAtom set body for more than 1.5nm Average body integration rate up to more than 20%.Its result makes BH reduce and be difficult to low yield strength ratio.Therefore, this room temperature keeps Time is the shortest more good, and solid solution and Quenching Treatment and reheating process can also be taked to enter continuously almost without the mode of time difference OK, the time of lower limit sets the most especially.

In this preliminary aging treatment, control until the programming rate of preliminary aging temperature and in preliminary aging temperature range Retention time.Wherein, in order to suppress the generation of the above-mentioned less atom set body being helpless to intensity, programming rate is preferably set to The biggest (fast) programming rate of 1 DEG C/more than s, preferably 5 DEG C/more than s.If programming rate is less than 1 DEG C/s, then cause The less atom set body being helpless to intensity generates in a large number, it is impossible to make to meet discipline Buddhist nun's leaf half in the atom set body of above-mentioned condition Footpath r_GAverage body integration rate up to more than 20% for the atom set body of more than 1.5nm.Its result makes BH reduce and be difficult to Low yield strength ratio.

If preliminary aging temperature is less than 60 DEG C or the retention time is less than 10hr, then the generation separating out core is insufficient, it is impossible to make Meet discipline Buddhist nun leaf radius r in the atom set body of above-mentioned condition_GAverage body integration rate for the atom set body of more than 1.5nm is many Reach more than 20%.Its result makes BH reduce.

On the other hand, if more than 120 DEG C or the retention time is more than 40hr, then in this preliminary aging treatment for preliminary aging temperature In separate out core growing amount excessively increase.Therefore, make the larger-size atom set body contributing to intensity reduce on the contrary, full The average body integration rate of the atom set body of the above-mentioned condition of foot become many and more than 1.5%, it is impossible to the yield tensile ratio of plate when making shaping As little as less than 0.50.

That is, if not making preliminary aging treatment be in these preferred condition and ranges, then plate when making car panel shape 0.2% yield strength as little as below 110MPa, and yield tensile ratio is the most as little as less than 0.50, on the other hand, it is difficult to after making BH 0.2% yield strength is more than 190MPa.

Embodiment

Hereinafter, enumerate embodiment and further illustrate the present invention, but the present invention is not limited by following embodiment, certainly at energy Enough meeting and can also suitably be changed enforcement in the range of the forward and backward objective stated, these are all contained in the technology model of the present invention In enclosing.

(embodiment of the 1st embodiment)

It follows that the embodiment of the 1st embodiment of the present invention is illustrated.In the present embodiment, solid solution is changed With the condition of the preliminary aging treatment after Quenching Treatment, 6000 line aluminium alloys that in DSC, the tissue of regulation is different are manufactured respectively Plate.Then, to the BH (coating baking hardening) after room temperature keeps 30 days after plate manufactures, the finger as press formability Target As yield strength, crimping processability as bendability are measured respectively, evaluate.

In above-mentioned DSC the way of the tissue of regulation by by 6000 line aluminium alloy plates of composition shown in table 1 according to table 2,3 institute Show the average cooling rate of Quenching Treatment after changing solution treatment like that respectively, the temperature of preliminary aging treatment afterwards, guarantor Hold the conditions such as time to carry out.Here, in the display of the content of each element in table 1, the numerical value of each element is blank situation Below display represents that its content is for detection limit.

The concrete manufacturing condition of aluminium alloy plate is as follows.The unified aluminum by each composition shown in DC casting melting table 1 Alloy ingot.At this moment, average cooling rate during casting is set to 50 from liquidus temperature to solidus temperature by each example all jointly DEG C/min.Then, after the equal heat treatment of all common ingot casting is carried out 540 DEG C × 6 hours only 1 section of each example, start in this temperature Hot roughing.Then, each example immediately utilizes finish to gauge to be hot-rolled down to thickness 3.5mm all jointly, makes hot rolled plate.Each example is all common to hot rolling After aluminium alloy plate implement the black annealing of 500 DEG C × 1 minute after, without cold rolling pass on the way in intermediate annealing and be processed rate 70% cold rolling, make the cold-reduced sheet of thickness 1.0mm.

And then, this each cold-reduced sheet is all jointly utilized the Equipment for Heating Processing of continuous way to carry out debatching, and limit is carried out by each example Batch limit and carry out modifier treatment (T4) continuously.Specifically, solution treatment is by by until the average heating rate of 500 DEG C sets Be 10 DEG C/sec, and keep carrying out for 10 seconds after arriving the target temperature of 560 DEG C, afterwards, according to shown in table 2,3 each averagely Rate of cooling carries out water-cooled or air cooling, is thus cooled to room temperature.After this cooling, in room temperature needed for shown in table 2 After time, use atmospheric furnace and oil bath, when utilizing the programming rate shown in table 2,3, arrival temperature, average cooling rate, holding Between carry out preliminary aging treatment.It is explained, for the cooling after this preliminary aging treatment, averagely cools down speed owing to change Degree, therefore carries out water-cooled or Slow cooling (natural cooling).

After these modifier treatment again each end article plate after 30 days room temperatures are placed, cut for test plate (panel) (base Body), and be determined to each for the above-mentioned DS C of test plate (panel), characteristic, evaluate.Their result is as shown in table 3.

(DSC)

The above-mentioned DSC of the tissue at 10 positions of the above-mentioned thickness of slab central part for test plate (panel) is measured, utilizes these 10 The meansigma methods at position, obtains the temperature range of 150～230 DEG C in the DSC (differential scanning calorimeter curve) of this plate respectively The peak heights (W/mg) of endothermic peak is as being equivalent to be helpless to the endothermic peak of Mg-Si cluster fusing of intensity and 240～255 DEG C The heat release that generates as the Mg-Si cluster being equivalent to contribute to intensity of the peak heights (μ W/mg) of exothermic peak of temperature range Peak.

But, above-mentioned in the differential thermal analysis of each measurement site of test plate (panel), at assay device: Seiko Instruments DSC220G, standard substance: aluminum, sample container: aluminum, Elevated Temperature Conditions: 15 DEG C/min, atmosphere: argon (50ml/min), sample weight: carry out respectively under the identical conditions of 24.5～26.5mg, by the curve of the differential thermal analysis of gained After (μ W) is standardized (μ W/mg) divided by sample weight, in the interval of 0～100 DEG C of above-mentioned differential thermal analysis plots, will The curve of differential thermal analysis is in the region of level and is set to the datum-plane of 0, and measures heat release peak height based on this datum-plane Degree.Their result is as Table 2,3.

(coating baking hardening)

As each mechanical property for test plate (panel) after room temperature is placed 30 days again after above-mentioned modifier treatment, asked by tension test Obtain 0.2% yield strength (As yield strength).It addition, respectively the most jointly utilize tension test to try to achieve it 30 for test plate (panel) these The artificial age-hardening that carries out again after it room-temperature aging 170 DEG C × 20 minutes process after (after BH) for test plate (panel) 0.2% yield strength (yield strength after BH).Then, by the difference (increase of yield strength between these 0.2% yield strengths Amount) have rated each BH for test plate (panel).

Described tension test be from above-mentioned each for take respectively test plate (panel) JIS Z 2201 No. 5 test films (25mm × 50mmGL × thickness of slab), at room temperature carry out tension test.Make the right angle side that draw direction is rolling direction of test film at this moment To.Draw speed for 5mm/ minute, was 20mm/ minute before reaching 0.2% yield strength below yield strength.Machinery The N number of feature measurement is 5, with each mean value calculation.It is explained, the measuring test film of yield strength after above-mentioned BH In, after utilizing this cupping machine that this test film gives the prestrain of stamping 2% simulating plate, then carry out above-mentioned BH process.

(crimping processability)

Crimping processability is only to respectively carrying out for test plate (panel) after room temperature is placed 30 days again after above-mentioned modifier treatment.Test uses Slat test film wide for 30mm, after 90 ° of bending machining of the interior bending R1.0mm formed to lower flange, carry out pressing from both sides every The inside that 1.0mm is thick, then the pre-curl that folded bent portion carries out successively folded bent to about 130 degree forward to inner side is processed, Folded bent 180 degree and make the flat crimping processing of end and internal contiguity.

The rough surface of bending section (curved edge portion) of this flat crimping of visualization, small crackle, big crackle The apparent condition such as generation, and carry out visual valuation according to following benchmark.Under following benchmark, 0～2 is acceptance line, more than 3 For defective.

0: flawless, rough surface, 1: slight rough surface, 2: the rough surface of severe, 3: tiny area crackle, 4: With wire continuous print face crack

Each example of numbering 0,1,8,13, the 16 of table 3～24 at the table 2 of the alloy numbering 0～12 employing table 1 In, in the composition compositing range of present embodiment and preferably condition and range manufactures, and comprise solution hardening process, The modifier treatment of preliminary aging treatment is carried out the most under the preferred conditions.Therefore, as Table 2,3, these each examples meet The DSC condition of regulation in present embodiment.That is, in the DSC of this plate, melt as the Mg-Si cluster being equivalent to be helpless to intensity The endothermic peak changed, the peak heights of the endothermic peak of the temperature range of 150～230 DEG C is 8 below μ W/mg, on the other hand, as quite In the exothermic peak that the Mg-Si cluster contributing to intensity generates, the peak heights of the exothermic peak of the temperature range of 240～255 DEG C is 20 More than μ W/mg.

Its result is: though the application carried out after the room-temperature aging that each example is after above-mentioned modifier treatment between low-temperature short-time Baking hardening, BH is the most excellent.It addition, as shown in table 3, even if after the room-temperature aging after above-mentioned modifier treatment, As surrender is strong Spending relatively low, therefore excellent to the press formability of car panel etc., crimping processability is the most excellent.That is, according to example of the present invention, i.e. In the case of making, after room-temperature aging, body bottom parts are carried out coating baking process, it is also possible to play 0.2% yield strength Difference for high BH, As0.2% yield strength that 0.2% yield strength is more than 170MPa after more than 100MPa and BH is The press formability of below 110MPa, good bendability.

On the other hand, the comparative example 2～7,9～13,14,15 of table 2 employ the alloy example 1 identical with the example of table 1, 2、3.But, as shown in table 2, these each comparative examples deviate from preliminary aging treatment condition institute preferably condition.Its result is: with In DSC deviation present embodiment, the scope of regulation and the example of same alloy composition are compared, and room-temperature aging is big, particularly room temperature As yield strength after keeping 30 days is higher, therefore press formability, the crimping poor in processability to car panel etc., and BH is also Difference.

In comparative example 2, after solution treatment until the average cooling rate in the Quenching Treatment of room temperature is too small.Therefore, Although the peak heights of endothermic peak A of the temperature range of 150～230 DEG C is 8 below μ W/mg, but the temperature model of 240～255 DEG C The peak heights relatively low (less) of exothermic peak B enclosed and less than 20 μ W/mg, contribute to the larger-size Mg-Si cluster of intensity Number density is less.This is due to until the rate of cooling of Quenching Treatment of room temperature is little, cause generating thick Mg in cooling₂Si And simple substance Si, it is impossible to obtain as the press formability that As0.2% yield strength is below 110MPa of target, good bending Processability.It addition, BH is the lowest.

In comparative example 3,9, after solutionizing until to preliminary aging treatment, (heating is opened after the Quenching Treatment of room temperature Begin) overlong time.Therefore, cause Mg-Si cluster that be helpless to intensity, that easily melt in the temperature-rise period of DSC a large amount of Generate, as shown in Figure 1 above, the peak heights higher (bigger) of endothermic peak A of the temperature range of 150～230 DEG C and more than 8 μ W/ mg.On the other hand, the peak heights of exothermic peak B of the temperature range of 240～255 DEG C the highest (bigger) and be 20 μ W/mg with On, the number density of the larger-size Mg-Si cluster contributing to intensity is the most.But, due to the above-mentioned size being helpless to intensity The number density of less Mg-Si cluster is too much, and therefore this harmful effect is too strong, it is impossible to obtain surrendering as the As0.2% of target Intensity is the press formability of below 110MPa, good bendability.It addition, BH is the lowest.

The programming rate of the preliminary aging treatment of comparative example 4,10 is the slowest.Therefore, cause being helpless to intensity, DSC's In temperature-rise period, the Mg-Si cluster of easily fusing generates in a large number, as shown in Figure 1 above, and the suction of the temperature range of 150～230 DEG C The peak heights higher (bigger) of thermal spike A and more than 8 μ W/mg.On the other hand, exothermic peak B of the temperature range of 240～255 DEG C Peak heights the highest (bigger) and be 20 more than μ W/mg, contribute to the number density of the larger-size Mg-Si cluster of intensity The most.But, owing to the number density of the less Mg-Si cluster of the above-mentioned size being helpless to intensity is too much, therefore this harmful effect Too strong, it is impossible to obtain as the press formability that As0.2% yield strength is below 110MPa of target, good bending machining Property.It addition, BH is the lowest.

In comparative example 5,11,14, the retention time the scope of 60～120 DEG C in preliminary aging treatment is too short and is 1 hour.Therefore, cause Mg-Si cluster that be helpless to intensity, that easily melt in the temperature-rise period of DSC to generate in a large number, as Shown in above-mentioned Fig. 1, the peak heights higher (bigger) of endothermic peak A of the temperature range of 150～230 DEG C and more than 8 μ W/mg.Separately On the one hand, the peak heights the highest (bigger) of exothermic peak B of the temperature range of 240～255 DEG C and be 20 more than μ W/mg, help The most in the number density of the larger-size Mg-Si cluster of intensity.But, owing to the above-mentioned size being helpless to intensity is less The number density of Mg-Si cluster is too much, and therefore this harmful effect is too strong, it is impossible to obtain as the As0.2% yield strength of target be The press formability of below 110MPa, good bendability.It addition, BH is the lowest.

In comparative example 6,12,15, the retention time the scope of 60～120 DEG C in preliminary aging treatment is long and is 48 hours.Therefore, the peak heights of exothermic peak B of the temperature range of 240～255 DEG C relatively low (less) and less than 20 μ W/mg, help Few compared with the number density of one large Mg-Si cluster in the size of intensity.Its result is cannot to obtain surrendering as the As0.2% of target Intensity is the press formability of below 110MPa, good bendability.It addition, BH is the lowest.

In comparative example 7, the arrival temperature in preliminary aging treatment is too high and is 130 DEG C, exceedes 120 as the upper limit ℃.Therefore, the larger-size Mg-Si cluster contributing to intensity reduces, exothermic peak B of the temperature range of 240～255 DEG C Peak heights relatively low (less) and less than 20 μ W/mg, the number density of the larger-size Mg-Si cluster contributing to intensity is few.Its knot Fruit is: BH step-down, on the other hand, As0.2% yield strength too high and more than 110MPa, and cannot obtain stamping Property, good bendability.

It addition, in the comparative example 25～34 of table 3, although preferred including above-mentioned preliminary aging treatment condition Scope manufactures, but uses the alloy numbering 13～22 of table 1, it is necessary to element M g, the content of Si deviate respective enforcement Scope or the impurity element amount of mode are too much.Therefore, as shown in table 3, compared with each example, at these comparative examples 24～33 In, the As yield strength after particularly room temperature keeps 30 days is the most too high, and press formability or crimping to car panel etc. add Work difference or BH are poor.

Comparative example 25 is the alloy 13 of table 1, and Si is very few.

Comparative example 26 is the alloy 14 of table 1, and Si is too much.

Comparative example 276 is the alloy 15 of table 1, and Sn is very few.

Comparative example 28 is the alloy 16 of table 1, and Sn is too much, cracks when hot rolling and cannot be carried out the manufacture of plate.

Comparative example 29 is the alloy 17 of table 1, and Fe is too much.

Comparative example 30 is the alloy 18 of table 1, and Mn is too much.

Comparative example 31 is the alloy 19 of table 1, Cr and Ti is too much.

Comparative example 32 is the alloy 20 of table 1, and Cu is too much.

Comparative example 33 is the alloy 21 of table 1, and Zn is too much.

Comparative example 34 is the alloy 22 of table 1, Zr and V is too much.

Proved by the result of above embodiment: for the formability after raising room-temperature aging and BH, need complete Portion meets the composition of regulation, each condition of DSC in present embodiment.

[table 1]

The hurdle that numerical value in the most each element is blank refers to below detection limit

[table 2]

[table 3]

It follows that the embodiment of the 2nd embodiment of the present invention is illustrated.After changing solutionizing and Quenching Treatment The condition of preliminary aging treatment, has manufactured the 6000 line aluminium alloy plates that in present embodiment, the tissue of regulation is different respectively.Then, The BH (coating baking hardening) after 30 days, As the index of press formability is kept to bend after plate manufactures in room temperature Take intensity, crimping processability as bendability is measured respectively, evaluates.

The way of above-mentioned tissue is by distinguishing 6000 line aluminium alloy plates of composition shown in table 4 according to as shown in table 5,6 Change the bars such as the average cooling rate of the Quenching Treatment after solution treatment, the temperature of preliminary aging treatment afterwards, retention time Part is carried out.Here, in the display of the content of each element in table 4, the situation display that the numerical value of each element is blank represents it Content is for detecting below limit.

The concrete manufacturing condition of aluminium alloy plate is as follows.The unified aluminum by each composition shown in DC casting melting table 4 Alloy ingot.At this moment, average cooling rate during casting is set to 50 from liquidus temperature to solidus temperature by each example all jointly DEG C/min.Then, after the equal heat treatment of all common ingot casting is carried out 540 DEG C × 6 hours only 1 section of each example, it is heated to 500 DEG C, start hot roughing.Then, each example immediately utilizes finish to gauge to be hot-rolled down to thickness 3.5mm all jointly, makes hot rolled plate.Each example is the most common After to the aluminium alloy plate enforcement black annealing of 500 DEG C × 1 minute after hot rolling, carry out without the intermediate annealing in cold rolling pass way Working modulus 70% cold rolling, makes the cold-reduced sheet of thickness 1.0mm.

And then, this each cold-reduced sheet is all jointly utilized the Equipment for Heating Processing of continuous way to carry out debatching, and limit is carried out by each example Batch limit and carry out modifier treatment (T4) continuously.Specifically, solution treatment is by by until the average heating rate of 500 DEG C sets Be 10 DEG C/sec, and keep carrying out for 10 seconds after arriving the target temperature of 560 DEG C, afterwards, according to shown in table 5,6 each averagely Rate of cooling carries out water-cooled or air cooling, is thus cooled to room temperature.After this cooling, in room temperature needed for shown in table 2 After time, use atmospheric furnace and oil bath, when utilizing the programming rate shown in table 5,6, arrival temperature, average cooling rate, holding Between carry out preliminary aging treatment.It is explained, for the cooling after this preliminary aging treatment, averagely cools down speed owing to change Degree, therefore carries out water-cooled or Slow cooling (natural cooling).

After these modifier treatment again each end article plate after 30 days room temperatures are placed, cut for test plate (panel) (base Body), and be determined to each for the above-mentioned tissue of test plate (panel), characteristic, evaluate.Their result is as shown in Table 5,6.

(tissue)

Above-mentioned assay method is utilized to be measured and resolve the solid solution capacity of the Mg+Si trying to achieve plate, utilize Three-dimensional atom to visit Each volume fraction etc. of the atom set body that pin field ion microscope measures.It is explained, in table 5,6, will utilize three-dimensional former The average body integration rate (%) of each atom set body that sub-probe field ion microscope measures is abbreviated as that " 3DAP measures atom set The average body integration rate (%) of body ".

It addition, in table 5,6, in " the average body integration rate of atom set body " that this hurdle is recorded, obtain and meet above-mentioned The volume V of the needle-like sample that the cumulative volume Σ Vi of the atom set body of the condition of regulation evaporates at above-mentioned electric field in embodiment_Al Average body integration rate (Σ Vi/V shared by_Al) × 100 (are being Σ Vi/V described in table 2,3_Al×100).It addition, also obtain Discipline Buddhist nun leaf radius r shared in the cumulative volume Σ Vi of above-mentioned atom set body_GAtom set body overall for more than 1.5nm Long-pending Σ Vi_{More than 1.5}Average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × 100 (it is being Σ Vi described in table 5,6_{More than 1.5}/ΣVi× 100)。

(coating baking hardening)

(crimping processability)

Crimping processability is only to respectively carrying out for test plate (panel) after room temperature is placed 7 days or 100 days again after above-mentioned modifier treatment.Test Use slat test film wide for 30mm, after 90 ° of bending machining of the interior bending R1.0mm formed to lower flange, press from both sides Every the inside that 1.0mm is thick, then the pre-curl that folded bent portion carries out successively folded bent to about 130 degree forward to inner side adds Work, folded bent 180 degree and make the flat crimping processing of end and internal contiguity.

The each of numbering 35,36,43,48, the 51 of table 6～58 at the table 5 of the alloy numbering 23～34 employing table 4 is invented In example, in the composition compositing range of present embodiment and preferably condition and range manufactures, and comprise at solution hardening Reason, the modifier treatment of preliminary aging treatment are carried out the most under the preferred conditions.Therefore, as shown in Table 5,6, these each examples are full The organization condition of regulation in foot present embodiment.That is, the solid solution capacity of above-mentioned Mg+Si be more than 1.0 mass % and 2.0 mass % with Descend and meet the pin that in above-mentioned present embodiment, the cumulative volume Σ Vi of the atom set body of the condition of regulation evaporates at above-mentioned electric field The scope of shape 1.5%, and discipline Buddhist nun leaf radius r shared in the cumulative volume Σ Vi of above-mentioned atom set body_GFor more than 1.5nm The cumulative volume Σ Vi of atom set body_{More than 1.5}Average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × 100 it is 20～70%.

Its result is: though the application carried out after the room-temperature aging that each example is after above-mentioned modifier treatment between low-temperature short-time Baking hardening, BH is the most excellent.It addition, as shown in table 6, even if after the room-temperature aging after above-mentioned modifier treatment, As surrender is strong Spending relatively low, and become low yield strength ratio, therefore excellent to the press formability of car panel etc., crimping processability is the most excellent.

That is, according to example of the present invention, even if body bottom parts to be carried out the situation of coating baking process after room-temperature aging Under, it is also possible to playing 0.2% yield strength difference is the height that 0.2% yield strength is more than 190MPa after more than 100MPa and BH BH, As0.2% yield strength is below 110MPa and the press formability of the low yield strength ratio less than 0.50, good bending add Work.Therefore, it is possible to have formability and baking application hardening concurrently, and high BHization and low yield strength ratio can be taken into account.

On the other hand, the comparative example 37～42,44～47,49,50 of table 5 employs the alloy identical with the example of table 4 Example 24,25,26.But, as shown in table 5, these each comparative examples deviate from preliminary aging treatment condition institute preferably condition.Its knot Fruit is: the solid solution capacity of above-mentioned Mg+Si, above-mentioned average body integration rate (Σ Vi/V_Al) × 100 or above-mentioned average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × 100 deviation present embodiments in regulation scope.Its result is: with the example phase of same alloy composition Ratio, room-temperature aging is big, and the As yield strength after particularly room temperature keeps 30 days is higher or becomes high low yield strength ratio, therefore to automobile The press formability of panel etc., crimping poor in processability or BH are poor.Therefore, it is impossible to have formability and baking application hardening concurrently, And high BHization and low yield strength ratio cannot be taken into account.

In comparative example 37, after solution treatment until the average cooling rate in the Quenching Treatment of room temperature is too small.Therefore, Generating thick Mg-Si and simple substance Si in cooling, formability is low.It addition, solid solution capacity after solutionizing reduces, above-mentioned averagely Volume fraction (Σ Vi_{More than 1.5}/ Σ Vi) × 100 also less than 20%, BH is the lowest.

In comparative example 38,44, after solutionizing until to preliminary aging treatment, (heating is opened after the Quenching Treatment of room temperature Begin) overlong time.Therefore, above-mentioned average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × 100 less than 20%, BH reduces, and nothing Method reaches low yield strength ratio.

The programming rate of the preliminary aging treatment of comparative example 39,45 is the slowest.Therefore, it is impossible to make above-mentioned average body integration rate (ΣVi_{More than 1.5}/ Σ Vi) × 100 up to more than 20%, BH is low.

In comparative example 40,46,49, the retention time the scope of 60～120 DEG C in preliminary aging treatment too short and It it is 1 hour.Therefore, the generation separating out core is insufficient, it is impossible to make above-mentioned average body integration rate (Σ Vi_{More than 1.5}/ Σ Vi) × more than 100 Reaching more than 20%, BH is low.

In comparative example 41,47,50, the retention time the scope of 60～120 DEG C in preliminary aging treatment long and It it is 48～45 hours.Therefore, making the growing amount separating out core in this preliminary aging treatment too much, the size contributing to intensity is bigger Atom set body reduce, above-mentioned average body integration rate (Σ Vi/V_Al) × 100 become many and more than 1.5%, it is impossible to when making shaping The yield tensile ratio of plate is as little as less than 0.50.

In comparative example 42, the arrival temperature in preliminary aging treatment is too high and is 130 DEG C, exceedes 120 as the upper limit ℃.Therefore, make the growing amount separating out core in this preliminary aging treatment too much, contribute to the larger-size atom set of intensity Body reduces, above-mentioned average body integration rate (Σ Vi/V_AlMore than 1.5% more than) × 100 become, As yield strength is too high, it is impossible to make into The yield tensile ratio of plate during shape is as little as less than 0.50.

It addition, in the comparative example 59～67 of table 6, although preferred including above-mentioned preliminary aging treatment condition Scope manufactures, but uses the alloy numbering 35～43 of table 4, it is necessary to element M g, the content of Si deviate respective enforcement Scope or the impurity element amount of mode are too much.Therefore, as shown in table 6, compared with each example, at these comparative examples 59～67 In, the As yield strength after particularly room temperature keeps 30 days is the most too high, and press formability or crimping to car panel etc. add Work difference or BH are poor.

Comparative example 59 is the alloy 35 of table 4, and Si is very few.

Comparative example 60 is the alloy 36 of table 4, and Si is too much.

Comparative example 61 is the alloy 37 of table 4, and Sn is very few.

Comparative example 62 is the alloy 38 of table 4, and Sn is too much, cracks when hot rolling and cannot be carried out the manufacture of plate.

Comparative example 63 is the alloy 39 of table 4, and Fe is too much.

Comparative example 64 is the alloy 40 of table 4, and Mn is too much.

Comparative example 65 is the alloy 41 of table 4, Cr and Ti is too much.

Comparative example 66 is the alloy 42 of table 4, and Zn is too much.

Comparative example 67 is the alloy 43 of table 4, Zr and V is too much.

Proved by the result of above embodiment: for the formability after raising room-temperature aging and BH, need complete Portion meets the composition of regulation, each condition of tissue in present embodiment.

[table 4]

[table 5]

[table 6]

It is described in detail by the present invention with reference to specific mode, but can be before without departing from the spirit and scope of the present invention Putting and carry out various change and amendment, this is self-evident to those skilled in the art.

Being explained, the application is based on Japanese patent application (Japanese Patent Application 2014-filed in 31 days March in 2014 074045) Japanese patent application (Japanese Patent Application 2014-074046) filed in 31, and 2014 on March, entire contents is passed through Quote and be incorporated herein.

Industrial applicability

According to the present invention it is possible to improve the BH after also having room-temperature aging concurrently and 6000 line aluminium alloy plates of formability.Its Result be the application of 6000 line aluminium alloy plates can be expanded to the panel of automobile, curved surface the most attractive in appearance is constituted, feature shows Etc. in the debatable outer panels of design structure.

Claims

1. a formability and the aluminium alloy plate of baking application hardening excellence, it is characterised in that it is with the score of quality % not Comprise Mg:0.2～2.0%, Si:0.3～2.0%, Sn:0.005～0.3% and surplus to be made up of Al and inevitable impurity Al-Mg-Si-type aluminum alloy plate,

In the differential scanning calorimeter curve of described aluminium alloy plate, as being equivalent to the endothermic peak that Mg-Si cluster melts, 150 ～the peak heights of the endothermic peak of the temperature range of 230 DEG C is 8 below μ W/mg and includes 0 μ W/mg, on the other hand, as being equivalent to The exothermic peak that Mg-Si cluster generates, the peak heights of the exothermic peak of the temperature range of 240～255 DEG C is 20 more than μ W/mg.

Formability the most according to claim 1 and the aluminium alloy plate of baking application hardening excellence, wherein, described aluminium alloy Plate also comprises selected from Fe: more than 0% and be less than 1.0%, Mn: more than 0% and be less than 1.0%, Cr: more than 0% and be Less than 0.3%, Zr: more than 0% and be less than 0.3%, V: more than 0% and be less than 0.3%, Ti: more than 0% and be 0.1% Below, Cu: more than 0% and be less than 1.0%, Ag: more than 0% and be less than 0.2% and Zn: more than 0% and be less than 1.0% In one kind or two or more.

3. a formability and the aluminium alloy plate of baking application hardening excellence, it is characterised in that it is with the score of quality % not Comprise Mg:0.3～1.0%, Si:0.5～1.5%, Sn:0.005～0.3% and surplus to be made up of Al and inevitable impurity Al-Mg-Si-type aluminum alloy plate,

Solid solution capacity at the Mg+Si utilized in the residue isolated solution of extraction based on hot phenol be more than 1.0 mass % and Below 2.0 mass %,

Further, as utilizing three-dimensional atom probe field ion microscope to measure the atom set body obtained, this atom set body is full Foot states condition: any one or both in the Mg atom comprising more than 10 altogether or Si atom, and no matter is comprised with it Mg atom or Si atom in any one atom as benchmark, become the atom of this benchmark and appointing in other adjacent atoms Mutual distance between one atom is below 0.75nm,

As the cumulative volume of these atom set bodies, according to will be respectively seen as the Ji Niye half during ball by each atom set body Footpath r_GThe volume Vi=4/3 π r of each atom set body calculated_G ³The cumulative volume ∑ Vi added and obtain is utilizing described three-dimensional The volume V of the described aluminium alloy plate that atom-probe field ion microscopy measures_A1Average body integration rate i.e. ∑ Vi/V shared by_A1 × 100 is the scope of 0.3～1.5%, and

In the cumulative volume ∑ Vj of described atom set body, by described discipline Buddhist nun leaf radius r_GAtom set body for more than 1.5nm Volume V_{More than 1.5}The cumulative volume ∑ Vi added and obtain_{More than 1.5}Shared average body integration rate (∑ Vi_{More than 1.5}/ ∑ Vi) × 100 be 20～ 70%.

Formability the most according to claim 3 and the aluminium alloy plate of baking application hardening excellence, wherein, described aluminium alloy Plate also comprises selected from Fe: more than 0% and be less than 1.0%, Mn: more than 0% and be less than 0.4%, Cr: more than 0% and be Less than 0.3%, Zr: more than 0% and be less than 0.3%, V: more than 0% and be less than 0.3%, Ti: more than 0% and be 0.1% Below, Cu: more than 0% and be less than 0.4%, Ag: more than 0% and be less than 0.2% and Zn: more than 0% and be less than 1.0% In one kind or two or more.