CN106342000B - Large aluminum alloy foundry goods antigravity casting casting system method for designing - Google Patents

Abstract

The invention discloses a kind of antigravity casting casting system method for designing, for the casting of large aluminum alloy foundry goods, meet aluminum alloy melt filling simultaneously and solidify the needs of feeding. The inventive method comprises: (1) carries out the subregion in feeding district according to casting structure; (2) determine antigravity casting casting system introducing position; (3) determine cross section structure and the size of stalk, cross gate, ingate; (4) calculate feeding length; (5) determine position and the size of vertical tube. The optimal design that the present invention can realize antigravity casting technique obtains dense structure, the foundry goods that crystalline quality is high, and can reduce foundry goods trial-production number of times, and shorten the lead time, improve the utilization rate of metal.

Description

Large aluminum alloy foundry goods antigravity casting casting system method for designing

Technical field

The present invention relates to a kind of antigravity casting casting system method for designing, meet aluminum alloy melt filling simultaneouslyWith the needs that solidify feeding. Use the present invention can obtain the aluminium alloy castings of high-compactness.

Background technology

Casting system design under gravity casting condition has formed comparatively complete theory, and in realityIn border, be widely used. In casting process, first aluminium alloy to be introduced to casting by casting systemIn part die cavity, carry out filling, then aluminium alloy solidifies, and obtains complete foundry goods. At traditional gravity castingIn process, running gate system only plays the effect of aluminium alloy steadily being introduced to casting mold, and requires ingate firstSolidify. Ingate and sprue sectional area are little, and cross gate sectional area is large. For preventing thermojunction, avoidThe thick large part of foundry goods arranges ingate.

Counter-gravity Casting originates from low pressure casting, is carried the earliest by British E.F.Lake in 1910Go out and applied for patent. Document " Countergravity Casting, Materials Engineering, 1988,105 (10) .8 " introduce Champaign, the Low Pressure Casting Technology of Illinois company, this technology is mainlyAround the cast growth of Engine Parts, automotive hub and motorcycle parts, casting dimension is logicalOften be less than 100kg.

Document " On the dynamic characteristics of mould-filling underCountergravity, Acta Metallurgica Sinica, 1999,12 (4): 528-530 " introduce weekThe adjustable pressure casting technology of Yao and academician's invention, adopts this technology to carry out the life of ultra-thin-wall precision aluminium-alloy foundry goodsProduce, and studied theoretically in thin-section casting stowing operation aluminium alloy flow stability and filled type order and askedTopic.

Existing Counter-gravity Casting due to for be mainly small sized metallic type foundry goods, in running gate systemIn design, except sprue is replaced with stalk, mainly continue to use the running gate system of traditional gravitational casting and establishMeter method.

Summary of the invention

In order to overcome the limitation that can only produce the following small-sized foundry goods of 100kg in prior art. The present invention carriesFor a kind of antigravity casting casting system method for designing, can produce the large aluminum alloy foundry goods of 1800kg, withIn time, meets aluminum alloy melt filling and solidifies the needs of feeding.

The technical solution adopted for the present invention to solve the technical problems is: a kind of large aluminum alloy foundry goods bob-weightPower casting casting system method for designing, comprises the steps:

(1), centered by the thick large part of foundry goods, taking thin-wall regions as border, foundry goods is decomposed into some benefitsContracting district, arranges ingate in thick large part, and ingate thickness is 1.5～2.5 times of casting thickness, works as foundry goodsCan capping when thick large part volume is larger, when small volume, remove the limit;

(2) running gate system should form from stalk-cross gate-ingate cross section and shrink gradually, its cross sectionArea ratio is, stalk: cross gate: ingate=1: (0.5～0.3): (0.4～0.2);

(3), when stalk is cylindrical, the cross section of cross gate and ingate can be designed to rectangle or circle;

(4) for thin-section casting, design clearance type casting system, the thickness d in its gap and casting section thicknessThe pass of δ is,

d＝(1.1～1.2)δ

The width l in gap and the pass of gap thickness d be,

l＝(0.8～1.5)d

(5) computational methods of ingate and vertical tube spacing are:

1. calculate overheated hot heat radiation time τ₁, formula is

${\mathrm{\τ}}_1=\frac{c\mathrm{\ρ}(T_p-T_L)\sqrt{a_m\mathrm{\π}}\mathrm{\δ}}{\sqrt{2}{\mathrm{\λ}}_m(T_L-T_m)}\frac{\mathrm{\δ}}{2}$

2. calculate latent heat of solidification heat radiation time τ_m, formula is

${\mathrm{\τ}}_m={\left(\frac{{\mathrm{L\ρ}}_S}{{\mathrm{\λ}}_m}\right)}^2\frac{a_m{\mathrm{\π\δ}}^2}{8{(T_m-T_L)}^2}$

3. calculate to solidify and fill type length L before beginning₁, formula is

$L_1=\sqrt{\frac{2{\mathrm{\δ}}^2({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)}{3\mathrm{\η}}}\sqrt{{\mathrm{\τ}}_1}$

4. solidify and fill type length L after beginning₂Calculate

$L_2^2=\frac{2}{3\mathrm{\η}}({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)\[{\mathrm{\δ}}^2{\mathrm{\τ}}_m+\frac{8{\mathrm{\λ}}_m\mathrm{\δ}}{3{\mathrm{\ρ}}_S\mathrm{\Δ}H}\frac{T_m-T_L}{\sqrt{2a_m\mathrm{\π}}}{\left(\sqrt{{\mathrm{\τ}}_m}\right)}^3+\frac{{\mathrm{\λ}}_m^2}{2{\left({\mathrm{\ρ}}_S\mathrm{\Δ}H\right)}^2}\frac{{(T_m-T_L)}^2}{a_m\mathrm{\π}}{{\mathrm{\τ}}_m}^2\]$

5. calculated population fills type length,

L_L＝L₁+L₂

6. solidify feeding distance and calculate L_c

$L_c=\frac{{\mathrm{\δc\ΔT}}_0}{tg\left(\frac{{\mathrm{\θ}}_c}{2}\right)(\mathrm{\Δ}H+2{\mathrm{c\ΔT}}_0)}$

7. determine casting system ingate minimum spacing L according to following condition_min

L_min≤min(L_L，L_C)

In various above, Δ H-latent heat of solidification

a_mThe temperature diffusivity of-casting mold

ΔP₀-mold filling pressure

C-quality thermal capacitance

δ-casting section thickness

R-freezing rate, i.e. crystalizing interface rate travel

ρ s-alloy density

λ_m-thermal conductivity

σ-aluminium alloy surface tension

η-aluminium alloy dynamic viscosity

ρ_LThe density of-aluminium alloy

G-acceleration of gravity

The pressure head of Δ h-aluminium alloy

τ₁-Re Re dispels the heat the time

τ_m-latent heat of solidification heat radiation the time

The principle of method for designing of the present invention is:

(1) determining of antigravity casting casting system function

Under heavy castings antigravity casting condition, casting system is except steady by aluminium alloy in conventional cast techniqueIntroduce outside the function in casting mold and transfer temperature field two additional functions below this research is clear and definite:

(a) pressure propagation function: ensure to fill solidifying in overall process after type completing, pressure can be as much as possibleBe delivered in the liquid phase region of whole foundry goods, play pressurization feeding effect;

(b) assist degassing function: owing to needing to pressurize by casting system under heavy castings antigravity casting conditionFeeding, can not adopt the open Runner Exhaust of conventional cast process, otherwise can make aluminium alloy overflow.

Therefore, casting system design must be looked after exhausting problem.

(2) antigravity casting casting system is introduced determining of position

In conventional cast technique, for fear of the formation thermojunction of thick large part, increase the weight of Formation of Shrinkage Porosity tendency,Conventionally avoid at the thick ingate of offering greatly, introduce aluminium alloy. And in antigravity casting process, need profitCarry out feeding by running gate system. In order to ensure the unimpeded of Feeding channel, form from foundry goods end to cast systemThe consecutive solidification process of system, exactly should, at the thick large part design ingate of foundry goods, make itself and cast systemSystem is communicated with. Ensure to keep conducting state in whole process of setting simultaneously.

(3) feeding district and partition method

Change foundry goods greatly for complex structure, sectional dimension, foundry goods be decomposed into some feeding district,And fill respectively the design of type and feeding technology. Under antigravity casting condition, the method for feeding Division, centered by thick large part, taking thin-wall regions as border, to arrange ingate in thick large part.

The present invention's advantage is compared to existing technology, because the present invention fills type in conjunction with antigravity casting processWith the feature of solidifying feeding, proposed with traditional gravity casting condition under the method for casting system comparison of design,Realize the optimal design of antigravity casting technique, combine with counter gravity casting equipment, obtain dense structure,The foundry goods that crystalline quality is high; The design of antigravity casting casting system is risen to and can be carried out from empirical methodThe level of theory analysis, thus foundry goods trial-production number of times can be reduced, shorten experimental period; Due to pre-advanced personGo designing and calculating, can reduce the use amount of casting system aluminium alloy, improved the utilization rate of metal.

Below in conjunction with drawings and Examples, the present invention is further described.

Brief description of the drawings

Certain airplane intake lip casting moulding system of Fig. 1 Pouring System Design Method design of the present inventionUpward view.

The structural representation of vertical tube in Fig. 2 Fig. 1.

Fig. 3 is certain aircraft type inlet lip foundry goods photo in kind of the running gate system casting in Fig. 1.

1-foundry goods in figure; 2-vertical tube; 3-gap; 4-cross gate; 5-ingate; 6-stalk; 7-ringShape running channel.

Detailed description of the invention

Referring to Fig. 1, Fig. 2, certain airplane intake lip casting of Pouring System Design Method design of the present inventionPart running gate system, this running gate system by stalk 6, cross gate 4, six ingates 5, ten vertical tubes 2,10 gaps 3 and ring gate 7 form, and have a cross gate being communicated with it on described stalk 64 and two ingates 5, on cross gate 4, there are four ingates that are communicated with it 5, foundry goods 1 internal layer is wateredNote feeding, and carry aluminium alloy to ring gate 7, has a ring gate 7 and six outward at foundry goodsIngate 5 connects, and has ten vertical tubes 2 skin cast to foundry goods 1 by gap 3 on ring gateAnd feeding.

Above-mentioned Design of Runner System concrete steps are as follows:

(1) according to certain airplane intake design feature, centered by the thick large part of foundry goods 1, with tenuityTerritory is border, and using foundry goods 1 skin as a feeding district, internal layer is divided into 6 centered by 6 technique lugsIndividual feeding district, whole foundry goods 1 comprises 7 feeding districts, carries out subregion feeding. In the thick large part of foundry goods 1Arrange ingate 5, ingate 5 thickness are 1.5 times of foundry goods 1 thickness;

(2) running gate system should form from stalk 6-cross gate 4-ingate 5 cross sections and shrink gradually,Its area of section ratio is, stalk: cross gate: ingate=1: 0.5: 0.4;

(3) stalk 6 is cylindrical, and the Cross section Design of cross gate 4 and ingate 5 is rectangle;

(4) thickness d in gap 3 is designed to 1.1 times of wall thickness δ of foundry goods, the width l in gap 3Be designed to 1.5 times of wall thickness.

(5) computational methods of ingate and vertical tube spacing are:

1. calculate overheated hot heat radiation time τ₁, formula is

${\mathrm{\τ}}_1=\frac{c\mathrm{\ρ}(T_p-T_L)\sqrt{a_m\mathrm{\π}}\mathrm{\δ}}{\sqrt{2}{\mathrm{\λ}}_m(T_L-T_m)}\frac{\mathrm{\δ}}{2}$

2. calculate latent heat of solidification heat radiation time τ_m, formula is

${\mathrm{\τ}}_m={\left(\frac{{\mathrm{L\ρ}}_S}{{\mathrm{\λ}}_m}\right)}^2\frac{a_m{\mathrm{\π\δ}}^2}{8{(T_m-T_L)}^2}$

3. calculate to solidify and fill type length L before beginning₁, formula is

$L_1=\sqrt{\frac{2{\mathrm{\δ}}^2({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)}{3\mathrm{\η}}}\sqrt{{\mathrm{\τ}}_1}$

4. solidify and fill type length L after beginning₂Calculate

$L_2^2=\frac{2}{3\mathrm{\η}}({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)\[{\mathrm{\δ}}^2{\mathrm{\τ}}_m+\frac{8{\mathrm{\λ}}_m\mathrm{\δ}}{3{\mathrm{\ρ}}_S\mathrm{\Δ}H}\frac{T_m-T_L}{\sqrt{2a_m\mathrm{\π}}}{\left(\sqrt{{\mathrm{\τ}}_m}\right)}^3+\frac{{\mathrm{\λ}}_m^2}{2{\left({\mathrm{\ρ}}_S\mathrm{\Δ}H\right)}^2}\frac{{(T_m-T_L)}^2}{a_m\mathrm{\π}}{{\mathrm{\τ}}_m}^2\]$

5. calculated population fills type length,

L_L＝L₁+L₂

6. solidify feeding distance and calculate Lc

$L_c=\frac{{\mathrm{\δc\ΔT}}_0}{tg\left(\frac{{\mathrm{\θ}}_c}{2}\right)(\mathrm{\Δ}H+2{\mathrm{c\ΔT}}_0)}$

7. determine casting system ingate minimum spacing Lmin according to following condition

L_min≤min(L_L，L_C)

In various above, Δ H-latent heat of solidification

a_mThe temperature diffusivity of-casting mold

ΔP₀-mold filling pressure

C-quality thermal capacitance

δ-casting section thickness

R-freezing rate, i.e. crystalizing interface rate travel

ρ s-alloy density

λ_m-thermal conductivity

σ-aluminium alloy surface tension

η-aluminium alloy dynamic viscosity

ρ_LThe density of-aluminium alloy

G-acceleration of gravity

The pressure head of Δ h-aluminium alloy

τ₁-Re Re dispels the heat the time

τ_m-latent heat of solidification heat radiation the time

Through the running gate system of said method design, utilize independently developed counter gravity casting equipment to castThe inlet lip part foundry goods of two certain aircrafts, as shown in Figure 3. Radioscopy through 100% dividesAnalyse, do not find any shrinkage porosite zero defect that is greater than secondary, reached the I class that navigation mark HB963-90 specifiesFoundry goods requirement.

Claims (1)

1. a large aluminum alloy foundry goods antigravity casting casting system method for designing, is characterized in that comprisingFollowing step:

(1), centered by the thick large part of foundry goods, taking thin-wall regions as border, foundry goods is decomposed into some benefitsContracting district, arranges ingate in thick large part, and ingate thickness is 1.5～2.5 times of casting thickness, works as foundry goodsCan capping when thick large part volume is larger, when small volume, remove the limit;

(2) running gate system should form from stalk-cross gate-ingate cross section and shrink gradually, its cross sectionArea ratio is, stalk: cross gate: ingate=1: (0.5～0.3): (0.4～0.2);

(3), when stalk is cylindrical, the cross section of cross gate and ingate can be designed to rectangle or circle;

(4) for thin-section casting, design clearance type casting system, the thickness d in its gap and casting section thicknessThe pass of δ is,

d＝(1.1～1.2)δ

The width l in gap and the pass of gap thickness d be,

l＝(0.8～1.5)d

(5) computational methods of ingate and vertical tube spacing are:

1. calculate overheated hot heat radiation time τ₁, formula is

${\mathrm{\τ}}_1=\frac{c\mathrm{\ρ}\left(T_p-T_L\right)\sqrt{a_m\mathrm{\π}}}{\sqrt{2}{\mathrm{\λ}}_m\left(T_L-T_m\right)}\frac{\mathrm{\δ}}{2}$

2. calculate latent heat of solidification heat radiation time τ_m, formula is

${\mathrm{\τ}}_m={\left(\frac{{\mathrm{L\ρ}}_S}{{\mathrm{\λ}}_m}\right)}^2\frac{a_m{\mathrm{\π\δ}}^2}{8{(T_m-T_L)}^2}$

3. calculate to solidify and fill type length L before beginning₁, formula is

$L_1=\sqrt{\frac{2{\mathrm{\δ}}^2({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)}{3\mathrm{\η}}}\sqrt{{\mathrm{\τ}}_1}$

4. solidify and fill type length L after beginning₂Calculate

$L_2^2=\frac{2}{3\mathrm{\η}}({\mathrm{\ΔP}}_0-{\mathrm{\ρ}}_{L}g\mathrm{\Δ}h)\[{\mathrm{\δ}}^2{\mathrm{\τ}}_m+\frac{8{\mathrm{\λ}}_m\mathrm{\δ}}{3{\mathrm{\ρ}}_S\mathrm{\Δ}H}\frac{T_m-T_L}{\sqrt{2a_m\mathrm{\π}}}{\left(\sqrt{{\mathrm{\τ}}_m}\right)}^3+\frac{{\mathrm{\λ}}_m^2}{2{\left({\mathrm{\ρ}}_S\mathrm{\Δ}H\right)}^2}\frac{{(T_m-T_L)}^2}{a_m\mathrm{\π}}{{\mathrm{\τ}}_m}^2\]$

5. calculated population fills type length,

L_L＝L₁+L₂

6. solidify feeding distance and calculate L_c

$L_c=\frac{{\mathrm{\δc\ΔT}}_0}{tg\left(\frac{{\mathrm{\θ}}_c}{2}\right)(\mathrm{\Δ}H+2{\mathrm{c\ΔT}}_0)}$

7. determine casting system ingate minimum spacing L according to following condition_min

L_mim≤min(L_L，L_C)

In various above, Δ H-latent heat of solidification

a_mThe temperature diffusivity of-casting mold

ΔP₀-mold filling pressure

C-quality thermal capacitance

δ-casting section thickness

R-freezing rate, i.e. crystalizing interface rate travel

ρ_S-alloy density

λ_m-thermal conductivity

σ-aluminium alloy surface tension

η-aluminium alloy dynamic viscosity

ρ_LThe density of-aluminium alloy

G-acceleration of gravity

The pressure head of Δ h-aluminium alloy

τ₁-Re Re dispels the heat the time

τ_m-latent heat of solidification heat radiation the time