CN101583730B - Method for producing a structural material made of magnesium-containing aluminium-based alloy - Google Patents

Abstract

The invention relates to foundry and rolling engineering. The inventive method for producing a structural material made of an aluminium-based alloy having the following component weighting ratio (%): 9.0-11.0 magnesium, 0.15-0.2 zirconium, 0.01-0.001 cobalt, 0.001-0.02 beryllium, aluminium being the rest, consists in producing a billet, in exposing it to heat treatment and in rolling said billet, wherein a melt used for producing the billet is crystallised in a rotating crystalliser with a gravitation factor ranging from 220 to 250 during the melt lifetime of 12-15 sec/kg.

Description

The production method of the structured material of making by magniferous aluminum base alloy

Technical field

The present invention relates to casting and rolling engineering.The existing production method of structured material that is used for automotive industry is generally based on producing ingot casting by the aluminum base alloy that contains magnesium, lithium, zinc etc. and to its traditional method that is rolled.

Background technology

The primary demand that is used for the structured material of automotive industry is that needs keep its ultimate stress in 300～400Mpa, and specific elongation is 30%～40%, and density is no more than 2.65g/cm ³, good weldability and erosion resistance.

There is not at present the alloy that satisfies these requirements.The existing lithium alloy of desired density is unsuitable for above purpose because intensity and plasticity-are not enough, with and relatively poor weldability, all other alloys are also because similar former thereby be not suitable for.Contain magnesium alloy and can be rolled into very firm product, surpass 9% magnesium, could satisfy its density requirements but have only this alloy to contain.Up to now, also do not develop by containing the alloy that surpasses 5% or 6% magnesium and make the method for rolled stock.

Known aluminum base alloy AMG5 of prior art (GOST standard 478961) and its production method.The prior art alloy has following chemical constitution (weight percent):

Magnesium 4.8～5.5

Manganese 0.3～0.6

Titanium 0.1～0.2

Iron 0.5～0.6

Silicon 0.1～0.2

Aluminium-surplus.

Rolled stock by the manufacturing of AMG5 alloy is widely used in aircraft and shipbuilding industry, it is by S.N Cherniak, " the Foil Manufacturing " of V.I.Karasevich and P.A.Kovalenko, Metallurgia Publishers, Moscow, the traditional method of describing in detail in 1968 makes.Produce ingot casting by the AMG5 alloy by semicontinuous method.Therefore, in the ingot casting matrix magnesium solubleness there is natural restriction.Too much magnesium forms its frangible eutectic thing of retardance around particle, it has determined the final plasticity-of ingot casting and alloy.In addition, the parabolic freezing interface of polycrystalline structure is the reason that does not have the uniform crystal orientation, i.e. the plasticity-difference in the whole ingot casting on the both macro and micro level.Usually, because this reason plasticity-is reduced by at least half.The plastic of alloy is characterised in that specific elongation is up to 4%～6%, and this is a numeral that does not obviously satisfy the automotive industry needs.

The method of producing AL8 very relevant with chemical constitution of the present invention and AL27 alloy (GOST standard 2695-75) is suitable for producing corrosion-resistant foundry goods, and this foundry goods can be heat-treated the intensity of improving them.Yet these methods only can be used for making ingot casting by above alloy.In addition, in principle, they can not be used for making plastic ingot casting by the alloy that comprises about 10% magnesium, and they are classified as castmethod for this reason.

Summary of the invention

The present invention seeks to develop a kind of method by the aluminum base alloy production structure material that comprises 9%～11% magnesium, it comprises the casting ingot casting, this ingot casting is heat-treated, and rolling this ingot casting, thereby the quality of improving the intensity and the plasticity-of rolled stock and being used to produce the method for sheet material.

This purpose is reached by developing a kind of method by the aluminum base alloy production structure material that comprises 9%～11% magnesium, described method comprises the production ingot casting, it is heat-treated, and rolling this ingot casting that contains magnesium, manganese and titanium, wherein by with following component proportions (weight percent) to wherein adding the mechanical property that zirconium, cobalt, beryllium and boron improve alloy again:

Magnesium 9.0～11.0

Zirconium 0.15～0.2

Cobalt 0.01～0.001

Beryllium 0.001～0.02

Aluminium-surplus.

In equaling the melt lifetime of 12～15 seconds/kg, in rotating mold, solidify under 220～250 the gravitation factor.Heat-treat with rolling according to following algorithm:

(a) according to its size, the heating ingot casting was used for hot rolling system in 2～4 hours under 340 ℃～380 ℃ temperature;

(b) hot rolling ingot to 4～8mm thickness under its 340 ℃～380 ℃ initial temperature, each cyclomorphosis maximum 30%.The final rolling temperature of work in-process rolled stock must be in 310 ℃～330 ℃;

(c) next stage, the work in-process rolled stock is cold rolling with maximum 50% distortion, and 0.5～2.0 hour process annealing hockets under rolling and 310 ℃～390 ℃ temperature, until the desired thickness that reaches 0.5～2.0mm; And

(d) under 400 ℃～450 ℃ temperature, make rolled stock annealing 5～40 minutes at last.

Claimed method is based on the application of the new physical phenomenon of solidifying of melt in the strong gravity field.Usually, the effect of this class field is as follows:

(a) strengthening diffusion process in the polycomponent melt arbitrarily, obtain intrusion-substitutional solid solution, can only recover the eutectic of minimum by this sosoloid.In addition, the eutectiferous volume that has formed minimizes, and is frozen into the independent combination that does not hinder blapharoplast; And

(b) even have polycrystalline structure, foundry goods or ingot casting also have account for might be orientated the main crystalline orientation of 80%～85% preset direction.

Therefore, claimed method helps to develop the aluminium base structured material that contains 9%～11% magnesium, and makes rolled stock by it.

The present invention rotating mold in realizes in the ingot casting production phase that by the method for the aluminum base alloy production structure material that comprises 9%～11% magnesium this Mould design depends on the shape and the weight of required ingot casting.In this case, the heat condition that solidifies depends on the particular design of die bushing.

The present invention be based on from the angle of lattice axes orientation see gravitational field to the solidified melt Theoretical Calculation that go out with effect experiment confirm.

Following this physical phenomenon of detailed analysis more.At the crystalline orientation that runs through new formation in the type field of force (gravitation, ultrasonic wave etc.) arbitrarily to be analyzed, necessary is to study at uneven distribution power F (x on the kinetics for solidified melt ^κ, be added in the power on the nuclear under external field influence ∏), and then be added in the power on the crystallite (particle) in the melt.

Hereinafter studied near the crystallite of point of suppon (freezing interface or matrix), it is at this power F (x ^κ, influence n) is distortion down.

Suppose that crystallite at one end has rigid support.Equilibrium equation is as follows in this case:

$\frac{{\mathrm{\δ\σ}}_{\mathrm{xx}}}{{\mathrm{\δ}}_x}+\frac{{\mathrm{\δ\σ}}_{\mathrm{xy}}}{{\mathrm{\δ}}_y}+\frac{{\mathrm{\δ\σ}}_{\mathrm{xz}}}{{\mathrm{\δ}}_z}=\frac{{\mathrm{\ρ}}_{3}F(x^k,\mathrm{\Π})}{M_{3\mathrm{ap}}}$

$\frac{{\mathrm{\δ\σ}}_{\mathrm{yx}}}{{\mathrm{\δ}}_x}+\frac{{\mathrm{\δ\σ}}_{\mathrm{yx}}}{{\mathrm{\δ}}_y}+\frac{{\mathrm{\δ\σ}}_{\mathrm{yz}}}{{\mathrm{\δ}}_z}=0$

$\frac{{\mathrm{\δ\σ}}_{\mathrm{zx}}}{{\mathrm{\δ}}_x}+\frac{{\mathrm{\δ\σ}}_{\mathrm{zy}}}{{\mathrm{\δ}}_y}+\frac{{\mathrm{\δ\σ}}_{\mathrm{zz}}}{{\mathrm{\δ}}_z}=0$

Wherein: σ _IkIt is stress tensor;

X, y and z are coordinates;

ρ is a density;

M _3apIt is nuclear quality.

For reaching a conclusion, accepted following restricted condition:

-except that σ _XxIn addition, lateral stress tensor σ _IkEqual zero.And

The free end of the crystallite of-length x=L has:

σ _xz＝σ _yz＝σ _zz＝0

Free energy can be described below:

$F=\frac{1}{2}{\mathrm{\σ}}_{\mathrm{xx}}{\mathrm{\ϵ}}_{\mathrm{xx}}=\frac{1}{2}{S}_{\mathrm{xxxx}}{\mathrm{\σ}}_{\mathrm{xx}}^2=\frac{1}{2}\frac{S_{\mathrm{xxxx}}{\mathrm{\ρ}}^2{F}^2(X^k,\mathrm{\Π})(L_O-X)}{M_{3\mathrm{ap}}}$

Wherein: ε _IkBe the distortion tensor, it equals S _IkLm* σ _Lm

S _IkLmIt is elastic constant;

$S_{\mathrm{iiLL}}=\frac{1}{2}{S}_{\mathrm{ikLm}}{\mathrm{\σ}}_{\mathrm{ik}}{\mathrm{\σ}}_{\mathrm{Lm}}$

σ _IkIt is kronecker delta.

Therefore, the surface energy of whole crystallite equals:

$E=\∫\mathrm{FdV}={\∫}_O^{L}F\left(x\right)S_3\mathrm{dx}$

For continuing to reach a conclusion, suppose:

E≈S _xxxx

Because the Young's modulus corresponding to direction X (along the longitudinal axis of crystallite) equals:

$E_x=\frac{1}{S_{\mathrm{xxxx}}}$

So

If crystal face hkL is perpendicular to axle OX, so:

$\frac{1}{E_x}=S_{11}-2(S_{11}-S_{12}-S_{44/2})A$

Wherein:

$A=\frac{h^2{k}^2+k^2{L}^2+L^2{h}^2}{{(h^2+k^2+L^2)}^2}$

Because for all the metal supposition S except that molybdenum ₁₁-S ₁₂-S _44/2＜0

-ratio 1/E so _x(III) has minimum value to the plane.

Direction (III) if with power F (x ^κ, vector ∏) conforms to, and with respect to other all directions, it will be preferred.No matter this conclusion shows the initial growth condition of melt type and axle (III) expressly, and the crystallite that postpones in the melt is all at power F (x ^κ, be orientated on direction ∏).

The crystallite that postpones is to be twisted near the ellipsoidal nuclear of growth fully by sphere, and it is connected on the cellulated freezing interface.

In principle, the orientation of crystallographic axis in growth cores (removed power F (x ^κ, ∏) outer) take place far to be connected on the freezing interface simultaneously at power F (x early than it ^κ, in the melt of variable viscosity, separate on direction ∏).

The direction of the perfect elasticity energy-minimum of lattice is at the maximum correct position of for example executing by rolling mill under the minimum external force of covering of solid continuous modification.This is a particularly important for the supersaturated solution of magnesium in aluminium under this situation, because this alloy has the intensity of improvement.

This method has been tested repeatedly, uses the suggestion of making as the basis with experiment to obtain the thick rolling body of hundreds of kilogram 2mm, 1mm, 0.5mm and 0.1mm.Rolling body is tested under laboratory condition.Test result is shown in table 1.By table 1 obviously as can be known, intensity and plastic best of breed are the parameters by method required for protection and use the alloy of Mg content about 10% to obtain.

Table 1

The present invention is suitable for industrial scale applications, because it can carry out in rotating mold known in the art, and obtains the result by changing the alloy production condition.The present invention can be used for by the AMG 10 alloy production structured material of any thickness almost.This invention can be used to produce the rolling stock that is used in body of motor cycle and motorcycle power section most effectively.

Claims (1)

1. the production method of a structured material of making by magniferous aluminum base alloy, comprise solidified melt and obtain ingot casting, this ingot casting is heat-treated, and rolling this ingot casting, be purpose wherein with alloy production structured material by the composition that contains following weight percent ratio:

In rotating mold under 220～250 the gravitation factor and in the melt lifetime of 12～15 seconds/kg solidified melt,

Wherein thermal treatment and rolling before, ingot casting heated 2～4 hours under 340 ℃～380 ℃ temperature, so ingot casting is hot-rolled down to thickness 4～8mm with the degree of deformation in each cycle maximum 30% under above temperature, and under the final rolling temperature of the work in-process rolled stock in 310 ℃～330 ℃ of scopes, then the degree of deformation with each cycle maximum 50% carries out the cold rolling of work in-process rolled stock, hocket with 0.5～2.0 hour process annealing under 310 ℃～390 ℃ temperature, until the desired thickness that obtains 0.5～2.0mm, under 400 ℃～450 ℃ temperature, make rolled stock annealing 5～40 minutes at last.