CN103305727A - Aluminum alloy plate for hood inner panel of automobile - Google Patents

Abstract

The present invention provides a 6000 series aluminum alloy plate having excellent impact absorption performance for pedestrian (head) collision, as well as other needed characteristics for a hood inner panel of an automobile. After being baked, the 6000 series aluminum alloy plate has the characteristic of: a 0.2% yield strength of 80-160MPa, and a Head Injury Criterion (HIC) of lower than 1000 mm/s<2> obtained by FEM analysis. Thereof, the 6000 series aluminum alloy plate has excellent impact absorption performance for pedestrian (head) collision, as well as other needed characteristics for the hood inner panel of the automobile.

Description

The hood inner panel aluminium alloy plate of automobile

Technical field

The present invention relates to a kind of hood inner panel Al-Mg-Si line aluminium alloy plate of automobile.

The alleged aluminium alloy plate of the present invention is the plate of heat-treating (modifier treatment) after cold rolling, namely is by the aluminium alloy plate before the stamping hood inner panel of making automobile.And then, in following record, also aluminium is called Al.

Background technology

In recent years, the pedestrian protecting in the motor-vehicle accident obtains rules, and the pedestrian protecting performance is also as the index of the evaluation grade of automobile hood (being also referred to as bonnet).On the other hand, automobile is because the high output of engine, and engine maximizes, and because multifunction, the part in the engine room also increases, and therefore, the space under the required engine shield of pedestrian protecting also diminishes.Therefore, in order to take into account preferred light design and pedestrian protecting performance, can become important with the exploitation that little space-efficient absorbs the automobile hood of crash energy.

Energy absorption when colliding on the automobile hood for the head that improves the pedestrian improves the pedestrian protecting performance, mostly carries out especially relevant with the shape of wainscot research (for example with reference to patent documentation 1).

In addition, also carried out by part on wainscot hypo-intense region being set and made its easy distortion, improved energy absorption, improved the research (for example with reference to patent documentation 2) of pedestrian protecting performance.

On the other hand, from considerations such as the environment of preserving our planet, in order to make Vehicle mass reduction; as this car panel; also as the panel material of engine shield, replace the ferrous materials such as steel plate, the application of the aluminum alloy materials of plasticity, more light weight that sintering application hardening is superior increases.

Outer panels (outside plate), wainscot (inner panel) for this motor car engine skin plate, as thin-walled and high-strength aluminium alloy plate, it is (below, also only be called 6000 be) aluminium alloy plate (cold-reduced sheet) that AA or the JIS 6000 of Al-Mg-Si system are used in all the time research.This 6000 line aluminium alloy plate must contain Si, Mg, and 6000 line aluminium alloys of especially superfluous Si type have described Si/Mg take the mass ratio calculation as the composition more than 1, have superior age hardening energy.Therefore, heating when the artificial aging (sclerosis) of the lower temperatures such as application sintering processes by the panel after stamping is processed and age hardening, yield strength improves, have the sintering application hardening that can guarantee as the intensity of necessity of car panel (below, baking hardening (Bake Hard) property=BH is also referred to as sinter-hardened property).

In addition, 6000 line aluminium alloy plates and Mg amount wait 5000 line aluminium alloys of many other of alloy amount etc. to compare, and the alloying element amount is less.Therefore, when the particle with described 6000 line aluminium alloy plates melts material (melting raw material) recycling as aluminium alloy, easily obtain 6000 original line aluminium alloy ingot bars, recycle is also superior.

But, so far, the scheme of the energy absorption the when head that does not still have to propose to make 6000 line aluminium alloy plates as the blank of such motor car engine skin plate self to have the pedestrian collides.If can improve the energy absorption of this 6000 line aluminium alloy plate self; then multiplying each other under the effect effect with the research of the shape of described wainscot, structure; energy absorption in the time of can colliding by the pedestrian head of automobile hood improves the pedestrian protecting performance.

Technical literature formerly

Patent documentation

Patent documentation 1: TOHKEMY 2008-24185 communique

Patent documentation 2: Japanese Unexamined Patent Application Publication 2010-515619 communique

As the car panel of engine shield panel etc. with and 6000 line aluminium alloy plates with superior characteristic, well-known, so far, the scheme that mostly proposes in history is that the composition from material, the aspect of tissue propose.

Just, can deserve to be called the prior art of the 6000 line aluminium alloy plates of using with the car panel such as described engine shield panel common be, take as car panel with and necessary described BH is superior develops as purpose.This be for, 6000 line aluminium alloy plates as blank, comprise that bending machining carrying out when stamping, the room-temperature aging sclerosis after suppressing plate is made keeps the characteristic of low yield strength (low strength), guarantees its plasticity.And, after being shaped, it is assembled on the body of a motor car, the heating during artificial aging (sclerosis) processing by the lower temperature when the application sintering processes and age hardening, and having in the lump becomes the BH of high-yield strength characteristic.

But, heating during application sintering processes by such lower temperature becomes high-yield strength, and intensity is too high, and it is large that the reactive force when pedestrian's head collides becomes, give the head injury, have also constant large problem of absorptive character that head collides the impact (energy) that causes.Consequently, in the automotive hood wainscot that is consisted of by 6000 line aluminium alloys self, can't satisfy normalized head injury value (HIC value).

Just, yield strength is descended, and also there are the following problems: also do not satisfy this head injury value, other the characteristic that requires that also can't have both as the hood inner panel of automobile is treatability, plasticity etc.

Summary of the invention

In view of such problem, the object of the invention is to, shock absorbing capability when providing a kind of pedestrian (head) to collide is superior, can also have both as the hood inner panel of automobile other the 6000 line aluminium alloy plates that require characteristic and the automotive hood that uses this aluminium alloy plate.

For reaching this purpose, automotive hood wainscot of the present invention with the main idea of aluminium alloy plate is: it is to calculate with quality %, contains Si:0.4～1.5%, Mg:0.2～1.0%, and surplus is the Al-Mg-Si line aluminium alloy plate of Al and inevitable impurity,

As the characteristic of having given this aluminium alloy plate that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes, 0.2% yield strength is 80～160MPa, and as the automotive hood wainscot after being shaped, according to the peaked relational expression of the product of 2.5 power of the average acceleration in the random time and time of origin, resolving the head injury value (HIC value) that draws by FEM is 1000mm/s ²Below.

The alleged described aluminium alloy plate of so-called the present invention refers to: to the aluminium alloy ingot bar of described composition implement respectively to homogenize thermal treatment, hot rolling, cold rolling and make cold-reduced sheet, this cold-reduced sheet is implemented thermal treatment described later, cold working and modified aluminium alloy plate.And, refer to the aluminium alloy plate by (certainly, before the application sintering processes of body of a motor car=artificial age-hardening processes before) before the stamping hood inner panel of making automobile.

The invention effect

In the present invention, the aluminium alloy plate of using as the automotive hood wainscot, not the high Al-Mg-Si line aluminium alloy plate of intensity of (behind the BH) after the application sintering processes of the known body of a motor car that uses at present, and use the low Al-Mg-Si line aluminium alloy plate of intensity (0.2% yield strength) behind this BH.

Thus, can make the blank of automotive hood wainscot is that Al-Mg-Si line aluminium alloy plate has head injury value (HIC value) and is 1000mm/s ²Below this characteristic.Consequently, no matter the shape of automotive hood wainscot how, perhaps, by with the pedestrian protecting of the automotive hood wainscot effect that multiplies each other with shape, structure, the shock absorbing capability in the time of can optimizing pedestrian's (head) collision.

By the way, although do not understand in detail yet its reason, only reduce as the intensity (0.2% yield strength) behind (as the tension test characteristic) described BH of mechanical characteristics, the HIC value not necessarily becomes 1000mm/s ²Below.This be presumably because: because the manufacturing processed of Al-Mg-Si line aluminium alloy plate or the difference of condition etc., as the intensity (0.2% yield strength) behind (as the tension test characteristic) described BH of mechanical characteristics even par, described head injury value is had the state etc. of microscopic structure of considerable influence also different, thereby described head injury value is also different.

According to the present invention, the shock absorbing capability in the time of can providing a kind of pedestrian (head) to collide is superior, and the head injury value is low, can also have both treatability, plasticity etc. as other the aluminium alloy plate of characteristic of the hood inner panel of automobile.Thus, can provide the automotive hood that uses this aluminium alloy plate.

Description of drawings

Fig. 1 is the explanatory view of the analytic construction example of expression hood inner panel of the present invention.

Fig. 2 is the explanatory view of the analysis condition of presentation graphs 1.

Fig. 3 is the explanatory view of presentation graphs 1,2 analysis result.

Fig. 4 is the explanatory view of form of evaluation test that schematically represents the treatability of embodiment.

Embodiment

Below, to embodiments of the present invention, each important document is specifically described.

The automotive hood wainscot:

The shape of Al-Mg-Si system (below, main refer to that 6000 are) aluminium alloy automotive hood wainscot processed, construct the common general technology that self adopts.For example, saying typically, as illustrative beam profile plate among Fig. 1 described later, can be the counter plate wainscot pruning (removing) and lightweight, be made of many beams that extend in length of wagon direction or vehicle-body width direction partly.In addition, also can be the wainscot of section cap shape, that is, it has: towards the inwall of outer panels, at the outer circumferential side of this inwall to the longitudinal wall of described outer panels lateral bend and spread all over around this longitudinal wall and and flange extension relative with described outer panels.And then, shape, structure that waveform muscle (PVC one De) that also can be nearest proposition etc. is improved for the protection of the pedestrian.

Blank 6000 line aluminium alloy plates given to this invention are shaped as the automotive hood wainscot by comprising the common stamping of bending machining or pruning etc.And this wainscot turns back the circumference of relative outer panels by carrying out, and the flanging processing that the flange circumference of wainscot is sandwiched through the binding resin layer and by integrated, make the motor car engine skin plate.

The necessary characteristic of automotive hood wainscot:

The necessary characteristic of the automotive hood wainscot that pedestrian protecting is used is that head injury value (HIC value) is 1000mm/s ²Below.As everyone knows; the pedestrian protecting performance of automobile hood wainscot is estimated by this head injury value (HIC value) in general; this HIC value is to resolve by FEM described later; according to following formula (1), provide with the maximum value of the product of 2.5 power of the average acceleration in the random time and time of origin.This HIC value is less, and the pedestrian protecting performance is more superior.

[formula 1]

$\mathrm{HIC}=(t2-t1){\left[1/(t2-t1)\underset{t1}{\overset{t2}{\&Integral;}}\mathrm{adt}\right]}_{\max }^{2.5}...\left(1\right)$

At this, a is the 3 axle resultant accelerations (unit is G) of head center of gravity, t1, t2 be 0＜t1＜t2 time t, to be the HIC value be the maximum time, computing time, (t2-t1) was decided to be below the 15msec.

For the HIC value that makes such automotive hood wainscot is below 1000, need to make 0.2% yield strength of this 6000 line aluminium alloy wainscot processed is 80～160MPa.Certainly, shape essential factor of wainscot etc. also has considerable influence to this HIC value.Just in the present invention; to adopt described general automotive hood wainscot to be shaped as prerequisite; also comprise so general shape, especially form automotive hood wainscot shape or the outer panels shape of pedestrian protecting shape, purpose is by the effect that multiplies each other with these shapes the pedestrian protecting performance of automotive hood wainscot to be improved.

0.2% yield strength at common automotive hood wainscot is that the reactive force when pedestrian's head collides significantly becomes greatly when surpassing the high-yield strength of 160MPa.Therefore; even form described general automotive hood wainscot shape, especially form the automotive hood wainscot of pedestrian protecting shape; no matter how are collision condition, automotive hood wainscot shape; also head is brought damage, the absorptive character of the impact energy that head collides are also constant large.Consequently, even form the automotive hood wainscot shape of described pedestrian protecting shape, although also depend on the collision condition, can't make the HIC value be 1000mm/s ²Below.

The parsing of HIC value:

Then, good and very relevant with the HIC value of the hood inner panel of the reality content as reproducibility, below explanation is resolved by FEM, obtains the method for the HIC value take this automobile hood wainscot as representative according to described formula (1).

By the way, so-called FEM resolves, and is well-known, is the common name of Finite element method (Finite Element Method), is the working solution analysis method that obtains the numerical solution of differential equation on the numerical value.More particularly, be zonule (key element) with the Region Segmentation that defines differential equation, by the differential equation of fairly simple and common each zonule of insertion approximation to function.

Fig. 1 represents to simulate the striking point condition that shape, structure and pedestrian's the head of the automotive hood of parsing collides, and Fig. 2 represents analysis condition.And Fig. 3 represents that object collides acceleration (=HIC value, the mm/s of the collision of the stroke (mm) of the strike thing (impacter) in the situation on the automobile hood of resolving and strike thing ²) between relation.

Fig. 1 is the exploded perspective view of automobile hood, represents the outer panels stereographic map of (showing outside among the figure) at upside, represents the wainscot stereographic map of (showing inner among the figure) at downside.Wainscot among Fig. 1 is that a kind of eight places of inboard are pruned (removing) and become the space, by the beam profile plate that three extensions is arranged in the length of wagon direction, have the beam of an extension to consist of in vehicle-body width direction.By the way, in the design of the outer panels of Fig. 1, consist of and oversimplify by more smooth single fillet.

In the wainscot of Fig. 1, the point that is represented by zero mark of the parts central part of illustrated body forward structure side is as the striking point prerequisite of resolving, that the simulation pedestrian head collides.And the strengthening part that rectangular tabular indicates on the wainscot parts central part of this body forward structure side is bump reinforcing member (being shown as bump section among the figure), and there is striking point in section in the central.

The HIC value take the automobile hood wainscot as representative is resolved, when estimating, the central part that is located on the bump reinforcing member (bump section) of this body forward structure side shown in Figure 1, that be present in wainscot is striking point.

On the bump reinforcing member of this hood inner panel, though not shown, between wainscot and outer panels, be provided with the strengthening part that is called as the pit reinforcing member.Under this pit reinforcing member, be on the wainscot of body forward structure side, as the engine shield support accessory that doubles as locking means, usually do not depend on vehicle and commonly have as shown in Figure 1 described bump reinforcing member.

This bump section position on the automobile hood wainscot is by described stiffening member constraint hood inner panel (position).Therefore, compare with other not restrained wainscot position, when pedestrian's head collided, the strength of materials of wainscot (0.2% yield strength) was large especially on the impact that the pedestrian protecting performance causes.Therefore, for the HIC value take hood inner panel as representative is resolved, estimated, the central part of preferably establishing on this bump reinforcing member is that striking point is stipulated.

In addition, rectangular tabular indicates two respectively in the end, the left and right sides of the parts of the vehicle rear side of the wainscot of Fig. 1, is that other strengthening part is hinged reinforcing member (being shown as hinged R/F among the figure).

The pedestrian protecting performance is that the HIC value is under the condition of world's benchmark shown in Figure 2, and take J-NCAP children collision condition as object, the striking point of the pedestrian head (head collision) of (described wainscot front portion) is estimated in simulated engine cover front portion.The weight of this strike thing (impacter) is 3.5kg, and collision speed is 35km, and the collision angle is 65DEG.

Collide to resolve and use general dynamic positive solution software LS-DYNA, under the condition of having considered the inner matter under the wainscot (engine etc.), study.Inner matter under this wainscot is by making the outer panels surface move and the rigid body wall made is simulated to the stroke directions of hitting thing, and establishing to the amount of movement of the stroke directions of hitting thing is 70mm.

The precondition of the HIC value of resolving:

According to the shape of described wainscot, the position of striking point or the difference of analysis condition, so also change by the HIC of described formula 1 parsing is worthwhile.Therefore, in HIC value regulation of the present invention, in order to obtain the reproducibility of analysis result, take the analysis condition shown in described Fig. 1,2 as prerequisite.That is, be set as the beam type shape of the wainscot shown in described Fig. 1,2, the position of striking point (point that is represented by zero mark of the parts central part of the front part of vehicle side of Fig. 1).Weight: 3.5kg.Collision speed: 35km.Collide angle: 65DEG.

Fig. 3 represents analysis result.In this Fig. 3, heavy line is the comparative example 25 (0.2% yield strength after the baking (bake) is 173MPa) in the table 2 of embodiment described later, dotted line is example 10 (0.2% yield strength after the baking is 144MPa), and fine line is example 1 (0.2% yield strength after the baking is 109MPa).That is be to be analysis result under the wainscot shape of the described Fig. 1 that is consisted of by 6000 line aluminium alloy plates of 1mm at thickness of slab.

At this, the automotive hood outer panels of Fig. 1, described stiffener are the composition identical with 6000 line aluminium alloy plates of above-mentioned wainscot, and its 0.2% yield strength is 230MPa.In addition, the thickness of slab of automotive hood outer panels is 1mm, and the thickness of slab of bump reinforcing member, hinged reinforcing member is 2.0m m.

The relation of yield strength and HIC value:

From the parsing example of this Fig. 3 as can be known, the centre of example 10 (0.2% yield strength 145MPa after the baking) and comparative example 25 (0.2% yield strength 179MPa after the baking), on the 160MPa degree given to this invention, can exist to make head injury value (HIC value) be reduced to 1000mm/s ²Following is critical.This fact also can obtain the support of Fig. 4 of the relation of 0.2% yield strength after the expression baking among the embodiment described later and HIC value.

In this Fig. 3, the wainscot yield strength is lower, more can reduce the HIC value, this be because, from the relation of the collision acceleration (G) of the stroke (mm) of the strike thing of transverse axis and the longitudinal axis as can be known, the wainscot yield strength is lower, collides the collision acceleration (two minor peaks) that produces by 2 times and more is lowered.That is, the wainscot yield strength is lower, and it is more late that wainscot collides the moment of inner matter under wainscot rigid bodies such as () engines, therefore, collides the collision acceleration (two minor peaks) that produces by described 2 times and become lower.In addition, the wainscot yield strength is lower, more can further increase the stroke of wainscot distortion.As can be known from these results, the wainscot yield strength is lower, and the HIC value is reduced to below 1000.

Therefore, the blank that makes the automotive hood wainscot namely 6000 line aluminium alloy plates, be below the 160MPa as 0.2% yield strength of automotive hood wainscot, that is 0.2% yield strength that the artificial age-hardening who, this aluminium alloy plate has been endowed further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes is below the 160MPa.Because this HIC value is preferably low, therefore more preferably establishing 0.2% yield strength is below the 110MPa, establishes the HIC value and hangs down to below 900.

The condition that 170 ℃ * 20 minutes artificial age-hardening after this 2% predeformation is given processes is the condition of creating conditions of general simulation automotive hood wainscot or body of a motor car.That is the texturizing condition that applies when, 2% predeformation is stamping to the automotive hood wainscot take 6000 line aluminium alloy plates of the present invention is as representative.In addition, application sintering circuit condition of (after being assembled in motor car engine skin plate or vehicle body) was as representative after artificial age-hardening's processing of 170 ℃ * 20 minutes was stamping take this.Certainly, the situation that these actual conditions are different from defined terms also more exists, as long as but satisfy this set condition, even if how many differences of condition, in most situation that the automotive hood wainscot of reality is made, also can make the hood inner panel of the superior and automobile that head injury value (HIC value) is low of the shock absorbing capability of pedestrian's (head) when colliding generally.

But, as the automotive hood wainscot, also must satisfy tractive rigidity, anti-concavity, flexural rigidity, torsional rigid etc. all the time to the desired fundamental property of hood inner panel.Described tractive rigidity be in order to suppress to wax or the locking automobile hood when recoverable deformation when being pressed into engine shield and essential.Concrete tractive rigidity is by determining as the young modulus of the engaged outer panels of motor car engine skin plate and the bonding station of thickness of slab and outer panels and wainscot.In addition, described anti-concavity also is that it is subject to yield strength and thickness of slab impact of described outer panels for essential because of the residual viscous deformation such as slungshot.And then described flexural rigidity is the recoverable deformation of the automobile hood circumference that produces of the reactive force of the power of drawing in order to suppress owing to the locking automobile hood and yielding rubber, shock bracket, caulking gum etc. and essential.Concrete flexural rigidity is subjected to the impacts such as the shape (2 moments of section), young modulus of wainscot and the reinforcing member of automobile hood circumference.In addition, described torsional rigid is affected by the flexural rigidity of automobile hood circumference and thickness of slab and the shape of wainscot central part.

Therefore, in order to satisfy as fundamental propertys such as the tractive rigidity of automotive hood wainscot, anti-concavity, flexural rigidity, torsional rigids, the improvement of key element that can be by the shape beyond the intensity of described wainscot, structure is dealt with.Therefore, even reduce the intensity of described wainscot, also can satisfy all the time to the desired fundamental property of automotive hood wainscot.In addition, satisfy described fundamental property for the light weight with the automotive hood wainscot turns to prerequisite, blank namely 6000 line aluminium alloy plates thickness of slab or be about 0.7mm to 2mm as the thickness of slab of the automotive hood wainscot that is shaped.

On the other hand, if the yield strength of automotive hood wainscot or blank 6000 line aluminium alloy plates is excessively low, then when stamping, when the processing such as conveyance blank aluminium alloy plate, input stamping machine, bring out distortion.Or the automotive hood wainscot after will being shaped also brings out distortion during from processing such as stamping machine taking-up, conveyances.In addition, owing to significantly producing because contact the distortion that causes, injured with press tool, transfer equipment, measuring device etc. in the stamping line, so cause in addition the misgivings as the quality decline of automotive hood wainscot.In addition, the forming height of wainscot high (deeply) etc., generally speaking shape is more complicated than flat outer panels, although require superior plasticity, if yield strength is excessively low, then also has press formability to descend and the possibility that can't be shaped.

For preventing this situation, establish more than the lower 50MPa of being limited to of 0.2% yield strength of automotive hood wainscot.For this reason, the blank of this automotive hood wainscot namely 6000 line aluminium alloy plates, as 0.2% yield strength of automotive hood wainscot, namely this aluminium alloy plate has been given 0.2% yield strength that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes and has been made as more than the 80MPa.

Based on above reason; shock absorbing capability when pedestrian's (head) is collided is superior, pedestrian protecting is superior and also satisfy as the automotive hood wainscot other require characteristic; if 0.2% yield strength of automotive hood wainscot is the scope of 80～160MPa, be preferably the scope of 80～120MPa.In addition, blank namely 6000 line aluminium alloy plates given the scope that 0.2% yield strength that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes is made as 80～160MPa, preferably be made as the scope of 80～120MPa.

Relation between the difference of tensile strength and yield strength and the HIC value:

In addition, when colliding, pedestrian's (head) produces viscous deformation by the distortion of automotive hood wainscot.In this viscous deformation, must follow the work hardening of aluminium alloy plate (wainscot), produce the Strength Changes that intensity uprises.Such work hardening is the reason that the shock absorbing capability (energy absorption) the when pedestrian of automotive hood wainscot is collided descends.Therefore, the purpose that preferably work hardening of following such viscous deformation is suppressed is the shock absorbing capability when colliding for the pedestrian who improves the automotive hood wainscot.Therefore, preferably reduce as far as possible the poor of the tensile strength of automotive hood wainscot and 0.2% yield strength.This essential factor still only reduces as the intensity (0.2% yield strength) after described artificial age-hardening's processing of tension test characteristic, and the HIC value not necessarily becomes 1000mm/s ²Following reason.

Therefore, in order to make the HIC value be 1000mm/s ²Below, preferably, making blank is that the tensile strength of the aluminium alloy plate after the described modifier treatment and the difference of 0.2% yield strength are below the 70MPa, more preferably below the 50MPa.By the way, this blank is that the tensile strength of the aluminium alloy plate after the described modifier treatment and poor (value) of 0.2% yield strength have the tendency that generally diminishes after described artificial age-hardening processes, but think that both have good dependency, so be that value after the described modifier treatment is stipulated with blank.

Need to prove, be that the tensile strength of the aluminium alloy plate after the described modifier treatment and the difference of 0.2% yield strength are below the 70MPa if make blank, and more preferably below the 50MPa, the press formability that then strikes out the automotive hood wainscot also improves.

The automotive hood outer panels:

With the automotive hood outer panels of the wainscot combination with such characteristic be steel plate system, or by the aluminium alloy identical with wainscot with more high-intensity aluminium alloy plate system.When steel plate is used for the automotive hood outer panels, in order to prevent because engage the galvanic corrosion (corrosion) that causes with the different material of aluminium alloy wainscot, also need to make resin between between panel, or make the engaging mechanisms such as bolt between and stiffener between etc. the insulation countermeasure.In addition, if consider the trouble of selecting or distinguishing in the recycle (recycling) of automotive hood (panel), compare the different material combination each other with steel plate, the preferred aluminium alloy system identical with wainscot more preferably described later same 6000 is associated gold and forms.

But, even 6000 line aluminium alloys identical with wainscot form, in order to satisfy as fundamental propertys such as the required intensity of outer panels, tractive rigidity, anti-concavity, flexural rigidity, torsional rigids, need intensity to be higher than the 6000 line aluminium alloy plates that wainscot is used, preferably its yield strength is more than 160.That is, as the automotive hood outer panels, specifically, preferably calculate with quality %, contain Si:0.4～1.5%, Mg:0.2～1.0%, surplus is Al and inevitable impurity, and is that 6000 line aluminium alloy plates of the shaping more than the 160MPa consist of by 0.2% yield strength.If from the blank 6000 line aluminium alloy plates of this composition, preferably having given 0.2% yield strength that the artificial age-hardening that further implements again 170 ℃ * 20 minutes after 2% the predeformation processes is more than the 160MPa.The upper limit of described 0.2% yield strength is not particularly limited, but is determined by the manufacturing gauge of plate, and the chances are about 280MPa.

The form of such automotive hood outer panels is preferably as the method for protecting pedestrian of automotive hood.The thickness of slab of described automotive hood outer panels is about 1mm to 2mm.

Strengthening part:

As the stiffener in automotive hood wainscot assembling (installation), shown in Figure 1 as described, hinged reinforcing member and bump reinforcing member are arranged, it is essential as being used for making the reinforcement of automotive hood wainscot tool intensity likely, rigidity.In addition, also optionally use in addition pit reinforcing member etc., in the present invention, allow at automotive hood or the various general strengthening parts of wainscot assembling.

Just, this strengthening part is also based on the reason identical with described automotive hood outer panels, compares the different material combination each other with steel plate, and the preferred aluminium alloy system identical with wainscot more preferably described later same 6000 is associated gold and forms.

But, form even identical with wainscot 6000 are associated gold, in order to satisfy as fundamental propertys such as the necessary intensity of strengthening part, rigidity, also need intensity to be higher than the 6000 line aluminium alloy plates that the automotive hood wainscot is used, preferably its yield strength is more than 160.That is, as described strengthening part, specifically, preferably calculate with quality %, contain Si:0.4～1.5%, Mg:0.2～1.0%, surplus is Al and inevitable impurity, and is that 6000 line aluminium alloy plates of the shaping more than the 160MPa consist of by 0.2% yield strength.If from the blank 6000 line aluminium alloy plates of this composition, preferably having given 0.2% yield strength that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes is more than the 160MPa.The upper limit of described 0.2% yield strength is not particularly limited, and is determined by the manufacturing gauge of plate, probably is about 280MPa.

The form of such strengthening part is preferably as the method for protecting pedestrian of automotive hood.The thickness of slab of described strengthening part is about 1mm to 4mm.

The composition of aluminium alloy plate:

The chemical composition of the 6000 line aluminium alloy plates that the automotive hood wainscot is used form be used to the characteristic that makes this wainscot become 0.2% yield strength in 80～160MPa and HIC value at 1000mm/s ²Following precondition.In other words, be used to make blank namely 6000 line aluminium alloy plates, to have given 0.2% yield strength that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes be that scope and the HIC value of 80～160MPa is 1000mm/s ²Following precondition.In addition, or the difference of the tensile strength that is used for making aluminium alloy plate after the described modifier treatment or automotive hood wainscot and 0.2% yield strength is below the 70MPa, more preferably below the 50MPa, and become the precondition of described HIC value.

Therefore, the composition of the 6000 line aluminium alloy plates that the automotive hood wainscot is used is: calculate with quality %, contain Si:0.4～1.5%, Mg:0.2～1.0%, surplus is Al and inevitable impurity.Need to prove, the % of the content of each element represents to refer to the meaning of quality %.

In addition, this composition also is be used to the described intensity that obtains them, the requiring characteristic of rigidity and essential for described automotive hood outer panels or described strengthening part.That is, as blank 6000 line aluminium alloy plates, for after having given 2% predeformation, make and the artificial age-hardening that further implemented 170 ℃ * 20 minutes 0.2% yield strength after processing is to be necessary more than the 160MPa.Need to prove, distinguishing as the making of the intensity of the wainscot of automotive hood, outer panels, strengthening part is by the content of the Si among the described composition, Mg is controlled, and undertaken by the heat-treat condition (modifier treatment) of the plate after cold rolling described later.

In the present invention, other elements beyond described Mg, the Si are essentially inevitable impurity, are the content (allowance) according to each element level of AA or JIS standard etc.Namely, viewpoint from resource circulation utilization, in the present invention, melting raw material as alloy, it is not only tire at the bottom of the high purity Al, contain more conduct and add 6000 of other elements beyond Mg, the Si of element (alloying element) and be associated in the situation of tire at the bottom of gold or other aluminium alloy particles, the low-purity Al etc. inevitable actual following other such elements of sneaking into a large amount of the use.And, reducing obstinately these elements, its refining self will cause cost to rise, and need to allow to contain to a certain degree.

Therefore, in the present invention, as inevitable impurity, preferably following element is limited in respectively following provisions according in the scope below the upper limit amount of AA or JIS standard etc., allow containing in this scope.Specifically, among the described inevitable impurity, be constrained to Fe:0.5% following (comprising 0%), Zn:0.5% following (comprising 0%), Cu:1.0% following (comprising 0%), Mn:0.5% following (comprising 0%), Cr:0.5% following (comprising 0%), Zr:0.3% following (comprising 0%), Ti:0.1% following (comprising 0%).

Below in above-mentioned 6000 line aluminium alloys of explanation each element contain scope and meaning or allowance.But the following description mainly is that the situation of the 6000 line aluminium alloy plates of using for the automotive hood wainscot that obtains necessary HIC value is carried out.By the way, in described automotive hood outer panels or described strengthening part, containing of each element had reason, the meaning of content, is common except the distinctive reason of automotive hood wainscot, the meanings such as low strength or HIC value.

Si：0.4～1.5％

Si obtains necessary intensity (yield strength) and essential element.In addition, be for the essential element that satisfies as the fundamental characteristics of automotive hood wainscot, be used to the important element that has both all characteristics such as the influential general extension of press formability that strike out panel.In order further to satisfy all characteristics of automotive hood wainscot, establishing preferably that Si/Mg calculates by quality ratio is more than 1.0, forms 6000 line aluminium alloys that for Mg surplus contains Si type Si, superfluous and forms.

If Si content is very few, then because the absolute magnitude of Si is not enough, so intensity significantly reduces, can't have both all characteristics such as the desired fundamental characteristics of described inner panel for car, general extension.On the other hand, if Si content is too much, then after giving 2% predeformation to aluminium alloy plate, 0.2% yield strength after 170 ℃ * 20 minutes artificial age-hardening processes becomes too high, in order to obtain being difficult to be below the 160MPa as the HIC value of necessity of automotive hood wainscot.In addition, form thick crystallisate and precipitate, bendability, general extension etc. significantly reduce.And then, also significantly damage weldability.Therefore, Si is 0.4～1.5% scope.

Mg：0.2～1.0％

Mg is the essential element that obtains necessary intensity (yield strength) with Si also.In addition, be for the essential element that satisfies as the fundamental characteristics of automotive hood wainscot, be used to the important element that has both all characteristics such as the influential general extension of press formability that strike out panel.

If Mg content is very few, the then absolute magnitude of Mg deficiency, so intensity significantly reduces, and can't have both all characteristics such as the desired fundamental characteristics of described inner panel for car, general extension.On the other hand, if Mg content is too much, then after giving 2% predeformation to aluminium alloy plate, 0.2% yield strength after 170 ℃ * 20 minutes artificial age-hardening processes becomes too high, in order to obtain the HIC value as necessity of automotive hood wainscot, be difficult to make it to become below the 160MPa.In addition, form thick crystallisate and precipitate, bendability, general extension etc. significantly reduce.And then, also significantly damage weldability.Therefore, the content of Mg is in 0.2～1.0% scope and to calculate by quality ratio Si/Mg be amount such more than 1.0.

(manufacture method)

Below, below the explanation aluminium alloy plate of the present invention manufacture method.The manufacturing process of aluminium alloy plate of the present invention self is well-established law or known method, and hot rolling, cold rolling is implemented in the laggard row of aluminium alloy ingot bar that forms at above-mentioned 6000 set members of the casting thermal treatment that homogenizes, and makes the thickness of slab of described regulation.

But, in the situation of the 6000 line aluminium alloy plates of using for the automotive hood wainscot that is used for obtaining necessary HIC value, in the cold rolling rear enforcement modifier treatment different from well-established law.Usually, in 6000 line aluminium alloy plates, if want further to improve described BH, implement common melt and quench treatment, the modifier treatment such as processing that reheat are at low temperatures afterwards made.But in the manufacture method of aluminium alloy plate of the present invention, such modifier treatment is owing to making BH too high thereby will not implement, and implements the such thermal treatment of aftermentioned.

Namely, as given to this invention, after having given 2% predeformation, the characteristic of the cold-rolled aluminum alloy sheet after further 170 ℃ * 20 minutes artificial age-hardening of embodiment processes again is 80～160MPa and to make described HIC value be 1000mm/s in order to make 0.2% yield strength ²Below, to the aluminium alloy ingot bar of described composition implement respectively to homogenize thermal treatment, hot rolling, cold rolling, make cold-reduced sheet, after this cold-reduced sheet being implemented with 1～50 hour thermal treatment of 300～450 ℃ of maintenances, further implement cold working with 0.3～5% working modulus, this is be used to the preferred manufacture method that obtains aluminium alloy plate of the present invention.

(melting, casting cooling speed)

At first, in melting, casting process, suitably select the common melting castings such as Continuous casting process, semicontinuous casting method (DC casting), casting melts the molten aluminium alloy of adjusting in the above-mentioned 6000 set member compositing ranges.At this, for aggregate of data (Network ラ ス タ) is controlled in the specialized range of the present invention, the average cooling rate during for casting preferably from the liquidus temperature to the solidus temperature, with more than 30 ℃/minutes, increases (quickening) as far as possible.

In the situation of not carrying out temperature (speed of cooling) control under such high-temperature area during in casting, the speed of cooling under this high-temperature area is inevitable slack-off.So, in the slack-off situation of the average cooling rate under high-temperature area, in the temperature range of this high-temperature area, the quantitative change of the crystallisate of thick generation is many, and the deviation of the plate width of ingot bar, the size of the crystallisate on the thickness direction or amount also becomes large.

(thermal treatment homogenizes)

Then, before hot rolling, the aluminium alloy ingot bar of described casting is implemented to homogenize thermal treatment.What the purpose of this thermal treatment that homogenizes (all thermal treatment) was to organize homogenizes, and namely eliminates the interior segregation of crystal grain in the ingot bar tissue.So long as can reach the condition of this purpose, just be not particularly limited.

Just, be more than 500 ℃ and less than fusing point, the time of homogenizing to be that scope more than 1 hour is suitably selected from the thermal treatment temp that homogenizes.If this homogenization temperature is low, then can't fully eliminate the segregation in the crystal grain, it works as the starting point of destroying, thereby puts limit property, bendability reduction.Afterwards, the hot rolling that will begin in a minute perhaps also can be cooled off and begun hot rolling after remaining to suitable temperature.

(hot rolling)

Hot rolling is according to rolling thickness of slab, by roughing operation processed and the finish rolling operation formation processed of ingot bar (slab).In described roughing operation processed, finish rolling operation processed, suitably adopt the roller mill of reversible type or tandem etc.

At this moment, surpass under the condition of solidus temperature in hot rolling (roughing system) beginning temperature, owing to causing oxidation, hot rolling self becomes difficulty.In addition, when hot rolling began temperature less than 350 ℃, the loading during hot rolling became too high, and hot rolling self becomes difficulty.Therefore, it is 350 ℃～solidus temperature that hot rolling begins temperature, more preferably the scope of 400 ℃～solidus temperature.

(process annealing)

Although before this hot-rolled sheet cold rolling or the process annealing between cold rolling mill train be not absolutely necessary, the characteristic such as plasticity is further improved implement.In this case, with 300～450 ℃, carried out 1～50 hour.

(cold rolling)

In cold rolling, above-mentioned hot-rolled sheet is rolled, make the cold-reduced sheet (also comprising coiled material) of the final thickness of slab of hope.But in order to make the further granular of crystal grain, preferred cold rolling rate is more than 60%.

(thermal treatment)

After this is cold rolling, carry out thermal treatment given to this invention.Thus, obtain giving after punching press 2% predeformation, 170 ℃ * 20 minutes artificial age-hardening, 0.2% yield strength after processing is that the following and described HIC value of 160MPa is 1000mm/s ²Following automotive hood wainscot aluminium alloy plate.And then the tensile strength that guarantees the automotive hood wainscot after the aluminium alloy plate after the described modifier treatment, described artificial age-hardening process and the difference of 0.2% yield strength be below the 70MPa, more preferably below the 50MPa, become described HIC value.

As example 1, this thermal treatment is after keeping 1～50 hour thermal treatment of described cold-reduced sheet under 300～450 ℃ the lower temperature, further implement 0.3～5% cold rolling, become the blank 6000 line aluminium alloy plates of automotive hood wainscot.Perhaps, as example 2, be implemented in 450～less than after keeping 0～60 second thermal treatment of described cold-reduced sheet under 500 ℃ the lower temperature, do not implement cold rollingly, just become so the blank 6000 line aluminium alloy plates of automotive hood wainscot.

Although 300～450 ℃ thermal treatment of described example 1 can be described as anneal, compare with the temperature province (about 520～570 ℃) of common melt processing, by extreme low temperature.By the thermal treatment of this condition, make aluminium alloy plate become BH given to this invention, be controlled to the strength level of the regulation of 0.2% yield strength below 160MPa as the automotive hood wainscot.If the thermal treatment temp of example 1 is excessively low, be lower than 300 ℃, then can not get described heat treated effect.In addition, if surpassing under 450 ℃ the high temperature, described heat treated effect is saturated.

And, after this thermal treatment (annealing), implement cold working, thus, making yield strength is more than the 50MPa, guarantees the plasticity of described blank plate or treatability or as the plasticity of automotive hood wainscot or treatability, necessary intensity, rigidity etc.But in this case, yield strength also is controlled to below 160MPa after the baking under the described conditions.If cold working rate is excessively low, then yield strength does not improve, and does not reach 50MPa.Be accompanied by the increase of cold working rate, although yield strength increases, if cold working rate surpasses 5%, stretching, extension and work hardening after then can worsen the plasticity reduction.Therefore, cold working rate is in 0.3～5% scope.As long as can implement the processing of the cold working rate of such regulation, can select the general cold working means such as cold rolling, smoother rectification.

By this cold working, transposition is imported in the tissue of blank 6000 line aluminium alloy plates of automotive hood wainscot again, when pedestrian's (head) collides, can suppress to be accompanied by the work hardening of the viscous deformation of automotive hood wainscot, improve the shock absorbing capability (energy absorption) of pedestrian when colliding.As this standard, reduce the poor of the tensile strength of automotive hood wainscot and 0.2% yield strength, can become 70MPa following, more preferably below the 50MPa, can guarantee to become described HIC value.This still only reduces as the intensity behind the described BH of tension test characteristic (0.2% yield strength), and the HIC value not necessarily becomes 1000mm/s ²Following reason.

450 of example 2～less than 500 ℃ thermal treatments is than the low temperature of common melt treatment temp, be implemented under this temperature keep 0～60 second thermal treatment of described cold-reduced sheet after, do not implement cold rollingly, just become so the blank 6000 line aluminium alloy plates of automotive hood wainscot.If the thermal treatment temp of example 2 is excessively low, be lower than 450 ℃, then can not get described heat treated effect.In addition, when the high temperature more than 500 ℃, become identically with common melt processing, B H becomes too high, and the yield strength of the wainscot after the application sintering processes becomes too high, and the HIC value becomes too high.

Speed of cooling after these thermal treatments is chilling, preferably with 50 ℃/second with on carry out.If speed of cooling is slow, then on grain circle, easily separate out Si, Mg ₂Si etc., the starting point of the cracking when easily becoming stamping, bending machining, described plasticity reduces.In order to ensure this speed of cooling, quench treatment is selected respectively the air coolings such as fan, spraying, hydro-peening, impregnating water-cooled means or condition.Just, the heat treatment phase ratio of the thermal treatment of this example 2 and described example 1 does not have the cold working after the thermal treatment, in the tissue of blank 6000 line aluminium alloy plates, can't again import the transposition that is caused by this cold working.Therefore, to when pedestrian's (head) collides, following the effect that suppresses in the work hardening of the viscous deformation of automotive hood wainscot to be lower than the thermal treatment of described example 1, poor as tensile strength standard, the automotive hood wainscot and 0.2% yield strength, embodiment is described as described later, also relatively uprises.

In the situation that described automotive hood outer panels, described strengthening part, before cold rolling, the situation of the 6000 line aluminium alloy plates used with the automotive hood wainscot of creating conditions is same.But, in order to realize the high strength of described automotive hood outer panels, described strengthening part, preferably obtain enough solid solution capacities of each element, or in order to make more granular of crystal grain, as usually, be preferably in to remain under the condition of the melt treatment temp more than 520 ℃ with the specified time and carry out.In addition, from suppressing to make the viewpoint of the thick grain circle compound formation that plasticity, flanging processibility reduce, based on described reason, means, the speed of cooling during quenching is preferably being carried out more than 50 ℃/second.And, in quench cooled after room temperature, preferably 1 hour with interior carry out with cold-reduced sheet remain in 70～250 ℃ temperature field reheat processing.

Below, enumerate embodiment and be described more specifically the present invention, but the present invention is not originally limited by following embodiment, within meeting the scope of aforementioned, purport described later, can suitably apply change and implement, this all is contained in technical scope of the present invention.

Embodiment

The following describes embodiments of the invention.By described composition or cold rolling after modifier treatment, distinguish and make 6000 different line aluminium alloy plates of yield strength condition given to this invention, mensuration, evaluation at room temperature keep 100 days mechanical characteristics and desired characteristics of wainscot after (room-temperature aging).The desired characteristic of so-called this wainscot, the treatability of 0.2% yield strength after referring to toast (B H), plate (only being expressed as treatability in the table 2), press formability.In addition, the yield strength value after the described baking is obtained the HIC value.

The differentiation of the yield strength of described plate is made as shown in table 2 such heat-treat condition (modified condition) that changes of 6000 line aluminium alloy cold-reduced sheets of composition as shown in table 1 and is carried out.That is, as shown in table 2, to the temperature of described example 1,2 heat treated pattern (℃), the condition of time (hour, h) carries out various changes and carries out.The thermal treatment of the cold-reduced sheet of example 1 is carried out in batch furnace, and further enforcement is cold rolling after thermal treatment, becomes the blank 6000 line aluminium alloy plates of automotive hood wainscot.The thermal treatment of the cold-reduced sheet of example 2 is carried out processing continuously stove, does not implement cold rolling after the thermal treatment, just becomes so the blank 6000 line aluminium alloy plates of automotive hood wainscot.

Need to prove, in the expression of each constituent content in table 1, the numeric representation of each element is "-", is that its content of expression is detecting below the gauge.

It is all common in each example that cold-rolled aluminum alloy sheet concrete created conditions, as described below.Commonly found the aluminium alloy ingot bar that each shown in the table 1 forms by the DC casting.At this moment, each example is also all the same, and the average cooling rate during for casting is made as 50 ℃/minutes from the liquidus temperature to the solidus temperature.Then, each example is also all the same, and ingot bar is carried out equal thermal treatment in 550 ℃ * 5 hours, then begins hot roughing system.Then, each example is also all the same, follows finish rolling system, and hot rolling is made hot-rolled sheet (coiled material) to thickness 3.5mm.For the aluminium alloy plate after the hot rolling, do not implement described cold rolling before or the process annealing between cold rolling mill train, carry out the cold rolling of working modulus 70%, each example is also all the same, makes the cold-reduced sheet (coiled material) of thickness 1.0mm.

Each example is also all the same, and this cold-reduced sheet is at room temperature kept 100 days (room-temperature aging), afterwards, cuts out respectively for test plate (panel) (blank), measures, estimates mechanical characteristics under condition described later.In addition, giving the artificial age-hardening who further implemented again 170 ℃ * 20 minutes after 2% the predeformation to after the described room-temperature aging each for test plate (panel) processes, 0.2% yield strength (BH), the treatability of plate, press formability after this baking are required characteristic as wainscot, under the aftermentioned condition, measure respectively, estimate.

In addition, resolve, estimate the HIC value take hood inner panel as representative.Therefore, the condition that comprises automotive hood outer panels, described stiffener, by analysis condition and the analytic method in described Fig. 1,2 explanations, as striking point, the yield strength value of obtaining after the described baking is resolved the head injury value (HIC value) that provides by described relational expression 1 by FEM with the central part on the described bump reinforcing member of hood inner panel.

Mechanical characteristics:

For the mechanical characteristics after 7 days room-temperature agings of test plate (panel), obtain tensile strength (As tensile strength), 0.2% yield strength (As yield strength) and general extension (As general extension) by tension test as each.In addition, to described each for test plate (panel), also commonly obtain 0.2% yield strength (yield strength behind the BH) for test plate (panel) after the described baking after 100 days the room-temperature aging by same tension test.

In described tension test, from described No. 5 test films (25mm * 50mmGL * thickness of slab) of respectively taking respectively JISZ2201 for test plate (panel), at room temperature carry out tension test.If the draw direction of the test film of this moment is the right angle orientation of rolling direction.Draw speed for 5mm/ divides, divided for 20mm/ later in yield strength before 0.2% yield strength.The N number that mechanical characteristics is measured is 5, calculates with mean value respectively.Need to prove, 2% the predeformation that the plate of test film stamping simulated of the yield strength behind the described baking hardening being measured usefulness gives by this tensile testing machine, carries out afterwards described BH and processes.

Treatability:

Treatability is to carry out under the condition of simulating to the processing when plate is dropped into stamping machine the time.Namely, the test plate (panel) that respectively supplies after described room-temperature aging cuts out the test film of 500mm * 500mm, as shown in Figure 4, front end towards above diameter 101.6mm spherical outstanding drift above, be the top position of 100mm apart from the distance on drift summit, flatly keep in the fallen mode in the center of test film.Then, make test film approximate horizontal ground freely falling body from this position, collide drift, test whether producing tension set on the test film.Three test films are carried out same test, by range estimation to three all produce being evaluated as of new tension set *, even a slice is also produced the △ that is evaluated as of slight tension set, with three all do not produce tension set be evaluated as zero.

Plasticity:

As described plasticity for test plate (panel), the cracking gauge height (LDH0) of outstanding plasticity evaluation usefulness is tested.In this test, with the described test film that is cut into length 180mm, width 110mm for test plate (panel), use the spherical outstanding drift of diameter 101.6mm, use R-303P as lubricant, give prominence to shaping with wrinkle press pressure 200kN, drift speed 4mm/S, the height (mm) when obtaining the test film cracking.Each sample is carried out three tests, adopt its mean value.This cracking gauge height is larger, means that outstanding plasticity is more superior, in order to satisfy the outstanding plasticity that the automotive hood wainscot is required of described Fig. 1 etc., gets final product so long as 25mm is above.

Use each example of numbering 1～10 of table 2 of the alloy numbering 1～4 of table 1, in composition compositing range of the present invention and in the optimum condition scope, make, thermal treatment.Therefore, described each example is as shown in table 2, although be low yield strength, other the characteristic that requires that satisfies as wainscot is treatability, plasticity etc., and satisfies the HIC value.Namely, as the characteristic of having given after the artificial age-hardening who further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes, 0.2% yield strength is 80～160MPa, and as the automotive hood wainscot that is shaped to resolve the HIC value that provides by described FEM be 1000mm/s ²Below.

Especially, each example of the numbering 1～6 of table 2 is implemented thermal treatment, the cold working of described example 1, and 0.2% yield strength is lower, and below 110MPa, the difference of tensile strength and 0.2% yield strength is also low, below 70MPa, can make the HIC value be reduced to 900mm/s ²Below.On the other hand, implement each example of numbering 7～10 of the heat treated table 2 of described example 2, although 0.2% yield strength below 160MPa, the HIC value is also at 1000mm/s ²Below, but being higher than example 1～6, the difference of tensile strength and 0.2% yield strength also uprises, more than 100MPa.In addition, after relatively with the baking of degree in the example situation each other of yield strength (such as example 2 and 5 each other or example 2 and 6 wait each other), the large example of the difference of tensile strength and yield strength is compared with the example that this difference is little as can be known, and the reduction effect of HIC value is large.

With respect to this, the comparative example 22～25 of table 2 uses the invention alloy example 2 of table 1.But described each comparative example is as shown in table 2, and the thermal treatment after cold rolling departs from optimum condition.Consequently, Fig. 3 as described is such for comparative example 25, and 0.2% yield strength after the baking is too high, is 173MPa, resolves the HIC value that provides by described FEM and surpasses 1000mm/s ²In addition, 0.2% yield strength of comparative example 22～24 is below the 110MPa, although resolve the HIC value that provides at 1000mm/s by described FEM ²Below, but do not satisfy as wainscot other require characteristic.

Cold rolling rate after the thermal treatment of comparative example 22 is excessively low, and 0.2% yield strength before the baking is excessively low, and less than 50MPa, treatability is excessively low.

Cold rolling rate after the thermal treatment of comparative example 23 is too high, and plasticity is excessively low.

The thermal treatment temp of comparative example 24 is excessively low, and 0.2% yield strength before the baking is excessively low, and less than 50MPa, treatability is excessively low.

The thermal treatment temp of comparative example 25 is too high, and is the same with common melt processing, and 0.2% yield strength after the baking is too high, resolves the HIC value that provides by described FEM and surpasses 1000mm/s ²

Make in preferable range although the comparative example 11～21 of table 2 comprises described heat-treat condition after cold rolling, use the alloy numbering 5～15 of table 1, the Mg of essential element or the content of Si break away from respectively the scope of the invention, or the impurity element amount is too much.Therefore, described comparative example 11～21 is as shown in table 2, characteristic after processing as the artificial age-hardening who further implemented 170 ℃ * 20 minutes after having given 2% predeformation, again, 0.2% yield strength is below the 100MPa, and to resolve the HIC value that provides by described FEM be 1000mm/s ²Below.But other the characteristic that requires that does not satisfy as wainscot is treatability, plasticity etc.

Comparative example 11 is alloys 5 of table 1, and Si is very few, and 0.2% yield strength before the baking is excessively low, and less than 50MPa, treatability is excessively low.

Comparative example 12 is alloys 6 of table 1, and Si is too much, and plasticity is poor.

Comparative example 13 is alloys 7 of table 1, and Fe is too much.

Comparative example 14 is alloys 8 of table 1, and Cu is too much.

Comparative example 15 is alloys 9 of table 1, and Mn is too much.

Therefore, the plasticity of described comparative example 12～15 is poor.

Comparative example 16 is alloys 10 of table 1, and Mg is very few, and 0.2% yield strength before the baking is excessively low, and less than 50MPa, treatability is excessively low.

Comparative example 17 is alloys 11 of table 1, and Mg is too much, and plasticity is poor.

Cu is too much.

Comparative example 18 is alloys 12 of table 1, and Cr is too much.

Comparative example 19 is alloys 13 of table 1, and Zn is too much.

Comparative example 20 is alloys 14 of table 1, and Zr is too much.

Comparative example 21 is alloys 15 of table 1, and Ti is too much.

Therefore, the plasticity of described comparative example 18～21 is poor.

Therefore; can support be used to the meaning that has both the requirement characteristic from the result of above embodiment; the described characteristic that requires is composition given to this invention, yield strength, the difference of tensile strength and 0.2% yield strength, HIC value etc. is as the pedestrian protecting of wainscot, plasticity, treatability etc.In addition, also supported for the meaning of the preferred manufacture method that satisfies this HIC value.

[table 1]

[table 2]

Industrial applicibility

According to the present invention, the shock absorbing capability in the time of can providing a kind of pedestrian (head) to collide is superior, as other 6000 line aluminium alloy plates that require characteristic also can have both of the hood inner panel of automobile.And then, the manufacture method of this aluminium alloy plate, the automotive hood that uses this aluminium alloy plate, method for protecting pedestrian etc. can also be provided in the lump.Consequently, the application of 6000 line aluminium alloy plates of light weight can be expanded to the engine shield of automobile.

Claims (3)

1. an automotive hood wainscot aluminium alloy plate is characterized in that,

It is to calculate with quality %, contains Si:0.4～1.5%, Mg:0.2～1.0%, and surplus is the Al-Mg-Si line aluminium alloy plate of Al and inevitable impurity,

As the characteristic of having given this aluminium alloy plate that the artificial age-hardening that further implemented again 170 ℃ * 20 minutes after 2% the predeformation processes, 0.2% yield strength is 80～160MPa, and as the automotive hood wainscot after being shaped, according to the peaked relational expression of the product of 2.5 power of the average acceleration in the random time and time of origin, resolving the head injury benchmark value that draws by FEM is 1000mm/s ²Below.

2. automotive hood wainscot aluminium alloy plate as claimed in claim 1, wherein,

The difference of the tensile strength of described aluminium alloy plate and 0.2% yield strength is below the 70MPa.

3. automotive hood wainscot aluminium alloy plate as claimed in claim 1, wherein,

Among the described inevitable impurity, be constrained to respectively below the Fe:0.5%, comprising 0%; Below the Zn:0.5%, comprising 0%; Below the Cu:1.0%, comprising 0%; Below the Mn:0.5%, comprising 0%; Below the Cr:0.5%, comprising 0%; Below the Zr:0.3%, comprising 0%; Below the Ti:0.1%, comprising 0%.

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