CN107909189A - A kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process - Google Patents

A kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process Download PDF

Info

Publication number
CN107909189A
CN107909189A CN201710983587.6A CN201710983587A CN107909189A CN 107909189 A CN107909189 A CN 107909189A CN 201710983587 A CN201710983587 A CN 201710983587A CN 107909189 A CN107909189 A CN 107909189A
Authority
CN
China
Prior art keywords
mrow
particle
msub
mfrac
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201710983587.6A
Other languages
Chinese (zh)
Other versions
CN107909189B (en
Inventor
牛晓峰
刘鸣
刘一鸣
王宝健
阎佩雯
宋振亮
黄志伟
程伟丽
侯华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiyuan University of Technology
Original Assignee
Taiyuan University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Taiyuan University of Technology filed Critical Taiyuan University of Technology
Priority to CN201710983587.6A priority Critical patent/CN107909189B/en
Publication of CN107909189A publication Critical patent/CN107909189A/en
Application granted granted Critical
Publication of CN107909189B publication Critical patent/CN107909189B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q10/00—Administration; Management
    • G06Q10/04—Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem"
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q10/00—Administration; Management
    • G06Q10/06—Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
    • G06Q10/063—Operations research, analysis or management
    • G06Q10/0635—Risk analysis of enterprise or organisation activities
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Information and communication technology [ICT] specially adapted for implementation of business processes of specific business sectors, e.g. utilities or tourism
    • G06Q50/04—Manufacturing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/30—Computing systems specially adapted for manufacturing

Landscapes

  • Business, Economics & Management (AREA)
  • Engineering & Computer Science (AREA)
  • Human Resources & Organizations (AREA)
  • Strategic Management (AREA)
  • Economics (AREA)
  • Tourism & Hospitality (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Entrepreneurship & Innovation (AREA)
  • Marketing (AREA)
  • General Physics & Mathematics (AREA)
  • General Business, Economics & Management (AREA)
  • Operations Research (AREA)
  • Quality & Reliability (AREA)
  • Game Theory and Decision Science (AREA)
  • Development Economics (AREA)
  • Mechanical Engineering (AREA)
  • Educational Administration (AREA)
  • Manufacturing & Machinery (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Primary Health Care (AREA)
  • Mold Materials And Core Materials (AREA)
  • Powder Metallurgy (AREA)

Abstract

The present invention relates to a kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process, it is the shrinkage cavity defect being directed to during aluminium alloy sand mould casting, simulation and forecast is carried out before actual casting, is conducive to reduce casting flaw in actual casting；Program is write using computer language VC++ as development platform, carry out computer operation, draw prediction result, show the distribution situation and size of shrinkage cavity defect in aluminium alloy castings sand casting, this Forecasting Methodology is few using equipment, and computational methods are general, reasonable, and calculating speed is fast, analog result is accurate, is adapted to shrinkage cavity defect under aluminium alloy castings sand casting to predict.

Description

A kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process
Technical field
The present invention relates to a kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process, belong to aluminium alloy sand mold Casting process optimization and the technical field of calculating.
Background technology
Aluminium alloy sand mould casting is to obtain anticipated shape, size and performance part after Al-alloy metal liquid stream enters casting mold solidification A kind of casting method；Technical process is：Al-alloy metal liquid is by cast gate successively by sprue, cross gate, ingate stream Enter cavity, full of whole cavity, expected casting is obtained after the complete cooled and solidified of casting.
Al-alloy metal liquid solidify when due in its contraction process feeding deficiency can produce shrinkage cavity, the formation of shrinkage cavity causes to cast Part defect, seriously affects the quality of casting；The formation of shrinkage cavity is a complicated process in Al-alloy metal liquid process of setting, is needed Show the whole process of its formation with the method for numbered analog simulation, it is accurate to predict that Al-alloy metal liquid process of setting forms contracting The distribution in hole and size, theoretical foundation is provided for optimize technique, mold design and prevention, reduction casting defect.
The content of the invention
Goal of the invention
The purpose of the present invention is for shrinkage cavity defect existing for aluminium alloy sand mould casting process, according to aluminium alloy sand mould casting Process of setting feature, is calculated by founding mathematical models and program, shows the forming process of shrinkage cavity, to aluminium alloy dumbbell shaped casting The distribution of shrinkage cavity is formed in process of setting and size is predicted, and is lacked for optimize technique, mold design, prevention and reduction casting Fall into and theoretical foundation is provided.
Technical solution
(1) aluminium alloy dumbbell shaped casting is obtained
1. prefabricated sand mold casting mold
Prepare dumbbell shaped wooden model and be molded；With sand paper polishing wooden model surface, make any surface finish；Using dumbbell shaped wooden model as shaping Model, sand mold mould is made with furan resin-sand, and sets zirconium oxide strainer gate in sand mold mould cast gate, spare；
1. smelting aluminium alloy liquation
Aluminium alloy 5kg ± 0.1kg is weighed, is placed in melting kettle, is heated to 720 DEG C ± 2 DEG C, and liquation is stirred Mix, using carbon trichloride degasification, then slagging-off, stands 5min；Molten aluminium alloy temperature is down to 690 DEG C ± 2 DEG C, stand-by；
3. sand casting
Molten aluminium alloy is injected into sand mold mould cast gate, molten metal enters mold cavity and is full of cavity；
4. cooling and taking-up casting
After casting, mould and its interior casting are placed in natural air and are cooled to 25 DEG C；Molded after cooling, take out dumbbell Shape casting；
5. clear up cast(ing) surface
With metallic brush cleaning cast(ing) surface, cast(ing) surface of polishing with mechanically cutting casting remainder, with sand paper, make surface clear It is clean, the shaping of dumbbell shaped casting；
(2) shrinkage cavity defect prediction model is established
1. establish threedimensional model, particle it is discrete and initialization
3D solid is established first with modeling software, it is then discrete to molten aluminium alloy progress particle in casting mold, cavity, The initial attribute of particle is set, is comprised the following steps that：
1) foundation of 3D solid
The threedimensional model of casting mold, molten aluminium alloy in cavity is established with 3 d modeling software；
2) particle is discrete and sets the initial parameter of particle
3 d modeling software exports 3D solid, discrete by particle, determines particle initial position；According to particle types not Together, the initial pressure of setting different attribute particle, density, viscosity, initial temperature, thermal conductivity factor, specific heat capacity；And determine time step Long and initial smooth length value, and provide that every 5000 time steps are a calculation stages；Casting mold particle is Gu Bi borders grain Son, border is handled using force method is repelled；
2. establish chained list searching method
By the way that Problem Areas is divided into the particle that small region determines to interact in the domain of influence, realizes particle pairing, deposit Particle is stored up to information, is comprised the following steps that：
1) Problem Areas is divided into region
All particles are divided by region according to particle initial position, each particle belongs to its specific region, dividing regions After domain, the particle in particle region and its peripheral region is only searched for during particle search；
2) particle search, pairing and storage particle are to information
Under conditions of only the particle in particle region and its peripheral region is searched for, using the position where particle i as The center of circle, 2 times of smooth length represent the domain of influence of particle i for the spheric region of radius；As particle i and particle j spacing rijNumber When value is less than or equal to 2 times of smooth length, it may be considered that particle i is matched with particle j, particle will be considered in follow-up calculate Influences of the j to particle i；In the case where meeting matching condition, in order to avoid repeating to match, the j particles numbering only searched is less than i Just complete to match during sub- numbering and store the particle to information；
After the completion of the calculating of each time step, the region division of particle, search, pairing, storage particle pair are re-started Information；
3. calculate particle temperature and acceleration
Al-alloy metal liquid particles temperature reduces, and temperature change can have an impact the physical parameter of metal liquid particles, base Realize that physical parameter is handled in the situation；In addition to considering temperature change, latent heat release model is also crucial in process of setting, Comprise the following steps that：
1) the calculating transitivity parameter processing of temperature；
The calculating transitivity parameter processing of particle temperature comprises the following steps that：
Temperature change calculating is carried out to all particles, expression is as follows：
In formula：Represent that i particle temperatures change with time rate, CiRepresent i particle specific heat capacities, ρ i represent that i particles are close Degree,Represent that j particles sum i particles influence in the domain of influence, N represents the particle number in the domain of influence, mjRepresent particle j Quality, ρjRepresent the density of j particles, λiRepresent the thermal conductivity factor of i particles, λjRepresent the thermal conductivity factor of j particles, TiRepresent i The temperature value of son, TjRepresent the temperature value of j particles, rijRepresent the distance between i particles and j particles,Represent smooth Functional gradient, is represented using index method, Greek alphabet subscript α and β denotation coordination direction；
For particle in cavity, calculating process medium viscosity, thermal conductivity factor and the change of density with temperature and change, specific table It is as follows up to formula：
The change of viscosity with temperature, physical relationship formula are as follows：
When particle temperature is at 536 DEG C -574 DEG C, η=0.024T2- 28T+8164.656, η unit are pas；Work as grain Sub- temperature is at 574 DEG C -576 DEG C, η=11.56-0.02T, and η units are pas；When particle temperature is at 576 DEG C -589 DEG C, η =1.013-0.00169T, η unit are pas；When particle temperature is at 589 DEG C -720 DEG C, η=0.0118, η units are pa s；η represents particle viscosity, and T represents particle temperature, unit DEG C；
Thermal conductivity factor variation with temperature, physical relationship formula are as follows：
When particle temperature is less than 536 DEG C, λ=170, λ units are W/ (m DEG C)；When particle temperature is at 536 DEG C -589 DEG C When, λ=1081.2-1.7T, λ units are W/ (m DEG C)；When particle temperature is at 589 DEG C -720 DEG C, λ=80, λ units are W/ (m·℃)；
Between different calculation stages, the change of density with temperature, physical relationship formula is as follows：
When particle temperature is less than 536 DEG C, ρ=2702, ρ units are kg/m3；When particle temperature is at 536 DEG C -589 DEG C, ρ =4336.8-3.05T, ρ unit are kg/m3；When particle temperature is at 589 DEG C -720 DEG C, ρ=2540, ρ units are kg/m3；
2) calculating of molten metal particle acceleration；
In formula：W represents smooth function, αdFor constant value Represent that j particles influence i particles in the domain of influence Effect summation, N represent the particle number in the domain of influence, mjRepresent the quality of particle j, piRepresent the pressure value of particle i, pjRepresent The pressure value of particle j, ρiRepresent the density of particle i, ρjRepresent the density of particle j, g represents the acceleration of gravity of particle, ηiWith ηjParticle i and particle j dynamic viscosity coefficients are represented respectively,Represent the speed difference of particle i and particle j, represented using index method, Greek alphabet subscript α and β denotation coordination direction, R represent the ratio of interparticle distance and smooth length；
The calculating of above formula needs to calculate particle pressure value p, and pressure value p calculation expressions are as follows：
In formula：p0Represent pressure initial value, ρ0Represent particle initial density, γ is constant, and g represents acceleration of gravity, H tables Show casting height；
In same calculation stages, rate of change of the density is tried to achieve by following formula, and expression is as follows：
In formula：Represent that particle i density changes with time rate,Represent that j particles influence to make on i particles in the domain of influence With summation, N represents the particle number in the domain of influence, mjRepresent the quality of particle j,Represent the speed difference of particle i and particle j, Represented using index method, Greek alphabet subscript α and β denotation coordination direction；
3) latent heat is handled
Latent heat processing is a factor for having to consider in process of setting, is embodied using the method for correcting specific heat capacitance latent Influence of the heat release to temperature computation, when molten metal particle temperature value is between liquidus curve and solidus, revised ratio Thermal capacitance CeCalculation formula is as follows：
In formula：CeRepresent specific heat capacity after correcting, CPRepresent former specific heat capacity, LfRepresent the latent heat of solidification of molten metal, TSRepresent Solidus temperature, TlRepresent liquidus temperature；
Former specific heat capacity CPVariation with temperature, physical relationship formula are as follows：
When particle temperature is less than or equal to 536 DEG C, Cp=0.0006T+0.82, CpUnit K J/ (kg DEG C)；When particle temperature Degree is at 536 DEG C -720 DEG C, Cp=1.14, CpUnit is KJ/ (kg DEG C)；T represents particle temperature, unit DEG C；
4. passing through a time step, the temperature, speed, position of particle are updated, comprised the following steps that：
1) particle changes with time rate in the temperature value that the temperature value at current time etc. is carved for the moment thereon plus temperature It is multiplied by time step；
2) molten metal particle rapidity and location updating are as follows：
Metal liquid particles are taken the opportunity spacer step in the velocity amplitude that the velocity amplitude at current time etc. is carved for the moment thereon plus acceleration It is long；Metal liquid particles are multiplied by time step in the positional value that the positional value at current time etc. is carved for the moment thereon plus acceleration Square multiplied by with
After the completion of one time step calculates, region division, search, pairing and particle temperature, the speed of particle are re-started The calculating of degree, position and physical parameter, terminates until calculating；
The shrinkage cavity defect Forecasting Methodology of aluminium alloy sand mould casting process is completed by computer program, using VC++ as development platform Programming is carried out, calculation procedure is as follows：
(3) prediction result
Total number of particles is 144000 in calculating, and numerical simulation result shows that shrinkage cavity, Numerical-Mode occurs in dumbbell shaped casting Intend result to coincide with measured result.
Beneficial effect：
The present invention has obvious advance compared with background technology, is for existing during aluminium alloy sand mould casting Shrinkage cavity defect phenomenon, carries out simulation and forecast before actual casting, is conducive to reduce casting in actual casting
Make defect；Program is write by development platform of VC++, carries out computer operation, draws prediction result, display aluminium closes Distribution situation, the size of shrinkage cavity defect in golden casting sand mold casting；This Forecasting Methodology is few using equipment, and computational methods are general, close Reason, calculating speed is fast, and analog result is accurate, is adapted to shrinkage cavity defect under aluminium alloy castings sand casting to predict, this Forecasting Methodology Available for the sand casting failure prediction of other ferrous metal, to optimize casting technique, avoid, the offer of casting shrinkage cavity defect is provided Instruct foundation.
Brief description of the drawings
Fig. 1, aluminium alloy dumbbell shaped casting front view
Fig. 2, aluminium alloy dumbbell shaped casting top view
Fig. 3, aluminium alloy dumbbell shaped casting side view
Fig. 4, aluminium alloy dumbbell casting sand mold as-cast condition figure
Shown in figure, list of numerals is as follows：
1st, upper dumbbell, 2, lower dumbbell, 3, neck, 4, punching block set, 5, sand mold mould, 6, upper dumbbell cavity, 7, lower dumbbell shape Chamber, 8, neck cavity, 9, zirconium oxide cast gate, 10, aluminum alloy melt, the 11, first movable rack, the 12, second movable rack, the 13, the 3rd opens Close frame, the 14, the 4th movable rack.
Embodiment
Below in conjunction with attached drawing, the present invention will be further described：
It is aluminium alloy dumbbell casting structure figure shown in Fig. 1,2,3, aluminium alloy dumbbell top is that upper dumbbell 1, lower part are mute under being Bell 2, centre are connected as one by neck 3, in dumbbell shaped.
It is aluminium alloy dumbbell shaped casting sand mold as-cast condition figure, each portion position, connection relation are correct, installation shown in Fig. 4 Firmly；Fixed outside the sand mold mould 5 that sand casting uses by punching block set 4, punching block set 4 is by the first movable rack 11, the second folding Frame 12, the 3rd movable rack 13, the 4th movable rack 14 are connected and fixed；Punching block covers 4 tops and is equipped with zirconium oxide cast gate 9；In sand mould It is upper dumbbell cavity 6 to have 5 internal upper parts, upper 6 lower part connecting neck portion cavity 8 of dumbbell cavity, the lower dumbbell shape of 8 lower part of neck cavity connection Chamber 7；Upper 6 top of dumbbell cavity is connected with zirconium oxide cast gate 9；It is aluminium in upper dumbbell cavity 6, neck cavity 8, lower dumbbell cavity 7 Aluminium alloy 10.

Claims (2)

  1. A kind of 1. shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process, it is characterised in that：
    (1) aluminium alloy dumbbell shaped casting is obtained
    1. prefabricated sand mold casting mold
    Prepare dumbbell shaped wooden model and be molded；With sand paper polishing wooden model surface, make any surface finish；Using dumbbell shaped wooden model as shaping mould Type, sand mold mould is made with furan resin-sand, and sets zirconium oxide strainer gate in sand mold mould cast gate, spare；
    2. smelting aluminium alloy liquation
    Aluminium alloy 5kg ± 0.1kg is weighed, is placed in melting kettle, is heated to 720 DEG C ± 2 DEG C, and liquation is stirred, is adopted With carbon trichloride degasification, then slagging-off, stands 5min；Molten aluminium alloy temperature is down to 690 DEG C ± 2 DEG C, stand-by；
    3. sand casting
    Molten aluminium alloy is injected into sand mold mould cast gate, molten metal enters mold cavity and is full of cavity；
    4. cooling and taking-up casting
    After casting, mould and its interior casting are placed in natural air and are cooled to 25 DEG C；Molded after cooling, take out dumbbell shaped casting Part；
    5. clear up cast(ing) surface
    With metallic brush cleaning cast(ing) surface, cast(ing) surface of polishing with mechanically cutting casting remainder, with sand paper, make surface cleaning, it is mute Bell-shaped casting is molded；
    (2) shrinkage cavity defect prediction model is established
    1. establish threedimensional model, particle it is discrete and initialization
    3D solid is established first with modeling software, it is then discrete to molten aluminium alloy progress particle in casting mold, cavity, set The initial attribute of particle, comprises the following steps that：
    1) foundation of 3D solid
    The threedimensional model of casting mold, molten aluminium alloy in cavity is established with 3 d modeling software；
    2) particle is discrete and sets the initial parameter of particle
    3 d modeling software exports 3D solid, discrete by particle, determines particle initial position；It is different according to particle types, The initial pressure of setting different attribute particle, density, viscosity, initial temperature, thermal conductivity factor, specific heat capacity；And determine time step With initially smooth length value, and provide that every 5000 time steps are a calculation stages；Casting mold particle is solid wall boundary particle, Border is handled using force method is repelled；
    2. establish chained list searching method
    By the way that Problem Areas is divided into the particle that small region determines to interact in the domain of influence, particle pairing, storage grain are realized Son comprises the following steps that information：
    1) Problem Areas is divided into region
    All particles are divided by region according to particle initial position, each particle belongs to its specific region, division region it Afterwards, the particle in particle region and its peripheral region is only searched for during particle search；
    2) particle search, pairing and storage particle are to information
    Under conditions of only the particle in particle region and its peripheral region is searched for, using the position where particle i as the center of circle, 2 times of smooth length represents the domain of influence of particle i for the spheric region of radius；As particle i and particle j spacing rijNumerical value be less than Or during smooth length equal to 2 times, it may be considered that particle i is matched with particle j, particle j will be considered to grain in follow-up calculate The influence of sub- i；In the case where meeting matching condition, in order to avoid repeating to match, the j particles numbering only searched is less than i particles volume Number when just complete match and store the particle to information；
    After the completion of the calculating of each time step, the region division of particle, search, pairing, storage particle are re-started to information；
    3. calculate particle temperature and acceleration
    Al-alloy metal liquid particles temperature reduces, and temperature change can have an impact the physical parameter of metal liquid particles, based on this Situation realizes that physical parameter is handled；In addition to considering temperature change, latent heat release model is also crucial in process of setting, specifically Step is as follows：
    1) the calculating transitivity parameter processing of temperature；
    The calculating transitivity parameter processing of particle temperature comprises the following steps that：
    Temperature change calculating is carried out to all particles, expression is as follows：
    <mrow> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>T</mi> <mi>i</mi> </msub> </mrow> <mrow> <mo>&amp;part;</mo> <mi>t</mi> </mrow> </mfrac> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <msub> <mi>C</mi> <mi>i</mi> </msub> <msub> <mi>&amp;rho;</mi> <mi>i</mi> </msub> </mrow> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <mfrac> <msub> <mi>m</mi> <mi>j</mi> </msub> <msub> <mi>&amp;rho;</mi> <mi>j</mi> </msub> </mfrac> <mfrac> <mrow> <mn>4</mn> <msub> <mi>&amp;lambda;</mi> <mi>i</mi> </msub> <msub> <mi>&amp;lambda;</mi> <mi>j</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;lambda;</mi> <mi>i</mi> </msub> <mo>+</mo> <msub> <mi>&amp;lambda;</mi> <mi>j</mi> </msub> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>T</mi> <mi>j</mi> </msub> <mo>-</mo> <msub> <mi>T</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> <mfrac> <mn>1</mn> <msub> <mi>r</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mfrac> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>W</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mo>&amp;part;</mo> <msubsup> <mi>x</mi> <mi>i</mi> <mi>&amp;alpha;</mi> </msubsup> </mrow> </mfrac> </mrow>
    In formula：Represent that i particle temperatures change with time rate, CiRepresent i particle specific heat capacities, ρiRepresent i particle densities, Represent that j particles sum i particles influence in the domain of influence, N represents the particle number in the domain of influence, mjRepresent the matter of particle j Amount, ρjRepresent the density of j particles, λiRepresent the thermal conductivity factor of i particles, λjRepresent the thermal conductivity factor of j particles, TiRepresent i particles Temperature value, TjRepresent the temperature value of j particles, rijRepresent the distance between i particles and j particles,Represent smooth function Gradient, is represented using index method, Greek alphabet subscript α and β denotation coordination direction；
    For particle in cavity, calculating process medium viscosity, thermal conductivity factor and the change of density with temperature and change, expression It is as follows：
    The change of viscosity with temperature, physical relationship formula are as follows：
    When particle temperature is at 536 DEG C -574 DEG C, η=0.024T2- 28T+8164.656, η unit are pas；Work as particle temperature At 574 DEG C -576 DEG C, η=11.56-0.02T, η units are pas；When particle temperature is at 576 DEG C -589 DEG C, η= 1.013-0.00169T η units are pas；When particle temperature is at 589 DEG C -720 DEG C, η=0.0118, η units are pas； η represents particle viscosity, and T represents particle temperature, unit DEG C；
    Thermal conductivity factor variation with temperature, physical relationship formula are as follows：
    When particle temperature is less than 536 DEG C, λ=170, λ units are W/ (m DEG C)；When particle temperature is at 536 DEG C -589 DEG C, λ= 1081.2-1.7T, λ unit are W/ (m DEG C)；When particle temperature is at 589 DEG C -720 DEG C, λ=80, λ units are W/ (m ℃)；
    Between different calculation stages, the change of density with temperature, physical relationship formula is as follows：
    When particle temperature is less than 536 DEG C, ρ=2702, ρ units are kg/m3；When particle temperature is at 536 DEG C -589 DEG C, ρ= 4336.8-3.05T, ρ unit are kg/m3；When particle temperature is at 589 DEG C -720 DEG C, ρ=2540, ρ units are kg/m3；
    2) calculating of molten metal particle acceleration；
    <mrow> <mi>W</mi> <mo>=</mo> <mfenced open = "{" close = ""> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&amp;alpha;</mi> <mi>d</mi> </msub> <mo>&amp;times;</mo> <mrow> <mo>(</mo> <mfrac> <mn>2</mn> <mn>3</mn> </mfrac> <mo>-</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> <msup> <mi>R</mi> <mn>3</mn> </msup> <mo>)</mo> </mrow> <mo>,</mo> </mrow> </mtd> <mtd> <mrow> <mn>0</mn> <mo>&amp;le;</mo> <mi>R</mi> <mo>&lt;</mo> <mn>1</mn> <mo>;</mo> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msub> <mi>&amp;alpha;</mi> <mi>d</mi> </msub> <mo>&amp;times;</mo> <mfrac> <mn>1</mn> <mn>6</mn> </mfrac> <msup> <mrow> <mo>(</mo> <mn>2</mn> <mo>-</mo> <mi>R</mi> <mo>)</mo> </mrow> <mn>3</mn> </msup> <mo>,</mo> </mrow> </mtd> <mtd> <mrow> <mn>1</mn> <mo>&amp;le;</mo> <mi>R</mi> <mo>&lt;</mo> <mn>2</mn> <mo>;</mo> </mrow> </mtd> </mtr> </mtable> </mfenced> </mrow>
    <mrow> <mfrac> <mrow> <msubsup> <mi>dv</mi> <mi>i</mi> <mi>&amp;alpha;</mi> </msubsup> </mrow> <mrow> <mi>d</mi> <mi>t</mi> </mrow> </mfrac> <mo>=</mo> <munderover> <mi>&amp;Sigma;</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msub> <mi>m</mi> <mi>j</mi> </msub> <mfrac> <mrow> <msub> <mi>&amp;eta;</mi> <mi>i</mi> </msub> <mo>+</mo> <msub> <mi>&amp;eta;</mi> <mi>j</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;rho;</mi> <mi>i</mi> </msub> <msub> <mi>&amp;rho;</mi> <mi>j</mi> </msub> </mrow> </mfrac> <msubsup> <mi>v</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mi>&amp;beta;</mi> </msubsup> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>W</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mo>&amp;part;</mo> <mi>R</mi> </mrow> </mfrac> <mo>-</mo> <munderover> <mi>&amp;Sigma;</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msub> <mi>m</mi> <mi>j</mi> </msub> <mfrac> <mrow> <msub> <mi>p</mi> <mi>i</mi> </msub> <mo>+</mo> <msub> <mi>p</mi> <mi>j</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;rho;</mi> <mi>i</mi> </msub> <msub> <mi>&amp;rho;</mi> <mi>j</mi> </msub> </mrow> </mfrac> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>W</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mo>&amp;part;</mo> <msubsup> <mi>x</mi> <mi>i</mi> <mi>&amp;alpha;</mi> </msubsup> </mrow> </mfrac> <mo>+</mo> <mi>g</mi> </mrow>
    In formula：W represents smooth function, αdFor constant value Represent that j particles seek i particle influences in the domain of influence With, the particle number in the N expression domains of influence, mjRepresent the quality of particle j, piRepresent the pressure value of particle i, pjRepresent particle j's Pressure value, ρiRepresent the density of particle i, ρjRepresent the density of particle j, g represents the acceleration of gravity of particle, ηiAnd ηjTable respectively Show particle i and particle j dynamic viscosity coefficients,Represent the speed difference of particle i and particle j, represented using index method, Greek alphabet Subscript α and β denotation coordination direction, R represent the ratio of interparticle distance and smooth length；
    The calculating of above formula needs to calculate particle pressure value p, and pressure value p calculation expressions are as follows：
    <mrow> <mi>p</mi> <mo>=</mo> <msub> <mi>p</mi> <mn>0</mn> </msub> <mo>&amp;lsqb;</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mi>&amp;rho;</mi> <msub> <mi>&amp;rho;</mi> <mn>0</mn> </msub> </mfrac> <mo>)</mo> </mrow> <mi>&amp;gamma;</mi> </msup> <mo>-</mo> <mn>1</mn> <mo>&amp;rsqb;</mo> </mrow>
    <mrow> <msub> <mi>p</mi> <mn>0</mn> </msub> <mo>=</mo> <mfrac> <mrow> <msup> <mn>30</mn> <mn>2</mn> </msup> <msub> <mi>gH&amp;rho;</mi> <mn>0</mn> </msub> </mrow> <mi>&amp;gamma;</mi> </mfrac> </mrow>
    In formula：p0Represent pressure initial value, ρ0Represent particle initial density, γ is constant, and g represents acceleration of gravity, and H represents casting Part height；
    In same calculation stages, rate of change of the density is tried to achieve by following formula, and expression is as follows：
    <mrow> <mfrac> <mrow> <msub> <mi>d&amp;rho;</mi> <mi>i</mi> </msub> </mrow> <mrow> <mi>d</mi> <mi>t</mi> </mrow> </mfrac> <mo>=</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msub> <mi>m</mi> <mi>j</mi> </msub> <msubsup> <mi>v</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mi>&amp;beta;</mi> </msubsup> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>W</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mo>&amp;part;</mo> <msubsup> <mi>x</mi> <mi>i</mi> <mi>&amp;beta;</mi> </msubsup> </mrow> </mfrac> </mrow>
    In formula：Represent that particle i density changes with time rate,Represent that j particles seek i particle influences in the domain of influence With, the particle number in the N expression domains of influence, mjRepresent the quality of particle j,Represent the speed difference of particle i and particle j, use Index method expression, Greek alphabet subscript α and β denotation coordination direction；
    3) latent heat is handled
    Latent heat processing is a factor for having to consider in process of setting, embodies latent heat using the method for correcting specific heat capacitance and releases The influence for temperature computation of being rivals in a contest, when molten metal particle temperature value is between liquidus curve and solidus, revised specific heat capacity CeCalculation formula is as follows：
    <mrow> <msub> <mi>C</mi> <mi>e</mi> </msub> <mo>=</mo> <msub> <mi>C</mi> <mi>P</mi> </msub> <mo>+</mo> <mfrac> <msub> <mi>L</mi> <mi>f</mi> </msub> <mrow> <mo>(</mo> <msub> <mi>T</mi> <mi>l</mi> </msub> <mo>-</mo> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>)</mo> </mrow> </mfrac> </mrow>
    In formula：CeRepresent specific heat capacity after correcting, CPRepresent former specific heat capacity, LfRepresent the latent heat of solidification of molten metal, TSRepresent solidus Temperature, TlRepresent liquidus temperature；
    Former specific heat capacity CPVariation with temperature, physical relationship formula are as follows：
    When particle temperature is less than or equal to 536 DEG C, Cp=0.0006T+0.82, CpUnit K J/ (kg DEG C)；When particle temperature exists At 536 DEG C -720 DEG C, Cp=1.14, CpUnit is KJ/ (kg DEG C)；T represents particle temperature, unit DEG C；
    4. passing through a time step, the temperature, speed, position of particle are updated, comprised the following steps that：
    1) particle is multiplied by the temperature value that the temperature value at current time etc. is carved for the moment thereon plus the temperature rate of changing with time Time step；
    2) molten metal particle rapidity and location updating are as follows：
    Metal liquid particles multiply time step in the velocity amplitude that the velocity amplitude at current time etc. is carved for the moment thereon plus acceleration；Gold Belonging to liquid particles, the positional value at quarter adds square that acceleration is multiplied by time step for the moment thereon in the positional value at current time etc. Multiplied by with
    After the completion of one time step calculates, region division, search, pairing and the particle temperature of particle, speed, position are re-started The calculating with physical parameter is put, is terminated until calculating；
    The shrinkage cavity defect Forecasting Methodology of aluminium alloy sand mould casting process is completed by computer program, is carried out by development platform of VC++ Programming；
    (3) prediction result
    Total number of particles is 144000 in calculating, and numerical simulation result shows that shrinkage cavity, numerical simulation knot occurs in dumbbell shaped casting Fruit coincide with measured result.
  2. 2. a kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process according to claim 1, its feature It is：Sand mold mould (5) that sand casting uses is exterior fixed by punching block set (4), punching block set (4) by the first movable rack (11), Second movable rack (12), the 3rd movable rack (13), the 4th movable rack (14) are connected and fixed；Punching block set (4) top is equipped with oxidation Zirconium cast gate (9)；It is upper dumbbell cavity (6) in sand mold mould (5) internal upper part, upper dumbbell cavity (6) lower part connecting neck portion cavity (8), the lower dumbbell cavity (7) of neck cavity (8) lower part connection；Upper dumbbell cavity (6) top is connected with zirconium oxide cast gate (9)；On It is aluminum alloy melt (10) in dumbbell cavity (6), neck cavity (8), lower dumbbell cavity (7).
CN201710983587.6A 2017-10-20 2017-10-20 Shrinkage cavity defect prediction method for simulating aluminum alloy sand casting process Active CN107909189B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710983587.6A CN107909189B (en) 2017-10-20 2017-10-20 Shrinkage cavity defect prediction method for simulating aluminum alloy sand casting process

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710983587.6A CN107909189B (en) 2017-10-20 2017-10-20 Shrinkage cavity defect prediction method for simulating aluminum alloy sand casting process

Publications (2)

Publication Number Publication Date
CN107909189A true CN107909189A (en) 2018-04-13
CN107909189B CN107909189B (en) 2021-10-01

Family

ID=61841603

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710983587.6A Active CN107909189B (en) 2017-10-20 2017-10-20 Shrinkage cavity defect prediction method for simulating aluminum alloy sand casting process

Country Status (1)

Country Link
CN (1) CN107909189B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110976830A (en) * 2019-12-06 2020-04-10 北京科技大学 Control method for casting defects of aluminum alloy gear shifting hub
CN111104763A (en) * 2020-01-03 2020-05-05 北京科技大学 Aluminum alloy semi-continuous casting defect tendency prediction method and device
CN113933474A (en) * 2021-09-13 2022-01-14 东风汽车零部件(集团)有限公司通用铸锻分公司 Structure and method for testing low-pressure casting shrinkage cavity tendency of aluminum alloy engine shell
CN114595567A (en) * 2022-03-03 2022-06-07 北京科技大学 Aluminum alloy casting heat crack simulation device and heat crack prediction method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102274947A (en) * 2011-08-16 2011-12-14 中北大学 Forecasting method for shrinkage cavity porosity of aluminum alloy low-pressure casting
CN106096215A (en) * 2016-07-28 2016-11-09 华东师范大学 A kind of sense of reality fluid simulation method relating to conduction of heat and Dynamic Viscosity
CN106202809A (en) * 2016-07-25 2016-12-07 太原理工大学 A kind of Optimization Prediction method simulating iron-sand mold casting casting cycle
CN106227954A (en) * 2016-07-27 2016-12-14 太原理工大学 A kind of Aluminum alloy gravity gravity die casting process optimization method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102274947A (en) * 2011-08-16 2011-12-14 中北大学 Forecasting method for shrinkage cavity porosity of aluminum alloy low-pressure casting
CN106202809A (en) * 2016-07-25 2016-12-07 太原理工大学 A kind of Optimization Prediction method simulating iron-sand mold casting casting cycle
CN106227954A (en) * 2016-07-27 2016-12-14 太原理工大学 A kind of Aluminum alloy gravity gravity die casting process optimization method
CN106096215A (en) * 2016-07-28 2016-11-09 华东师范大学 A kind of sense of reality fluid simulation method relating to conduction of heat and Dynamic Viscosity

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
曹文炅: "铸造充型过程SPH方法建模及数值模拟", 《中国博士学位论文全文数据库 工程科技Ⅰ辑》 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110976830A (en) * 2019-12-06 2020-04-10 北京科技大学 Control method for casting defects of aluminum alloy gear shifting hub
CN111104763A (en) * 2020-01-03 2020-05-05 北京科技大学 Aluminum alloy semi-continuous casting defect tendency prediction method and device
CN113933474A (en) * 2021-09-13 2022-01-14 东风汽车零部件(集团)有限公司通用铸锻分公司 Structure and method for testing low-pressure casting shrinkage cavity tendency of aluminum alloy engine shell
CN113933474B (en) * 2021-09-13 2024-04-05 东风汽车零部件(集团)有限公司通用铸锻分公司 Structure and method for testing shrinkage cavity tendency of aluminum alloy engine shell through low-pressure casting
CN114595567A (en) * 2022-03-03 2022-06-07 北京科技大学 Aluminum alloy casting heat crack simulation device and heat crack prediction method
CN114595567B (en) * 2022-03-03 2023-04-25 北京科技大学 Aluminum alloy casting hot crack simulation device and hot crack prediction method

Also Published As

Publication number Publication date
CN107909189B (en) 2021-10-01

Similar Documents

Publication Publication Date Title
CN107909189A (en) A kind of shrinkage cavity defect Forecasting Methodology for simulating aluminium alloy sand mould casting process
CN102274947B (en) Forecasting method for shrinkage cavity porosity of aluminum alloy low-pressure casting
CN107844852A (en) A kind of shrinkage defect Forecasting Methodology for simulating steel-casting sand casting process
CN101716653B (en) Anti-deformation method for casting vane of ultra-large mixed flow type water turbine
CN106202809B (en) A kind of Optimization Prediction method for simulating cast iron sand casting casting cycle
CN105598379B (en) A kind of Feeder Design method in thin-wall revolving body casting sand mold casting process predicted based on shrinkage defect
CN104439086A (en) Design method for risers during sand mould casting of non-axisymmetric complex castings
CN106227954B (en) A kind of Aluminum alloy gravity gravity die casting process optimization method
CN106392013A (en) Riser and pouring system for producing gray pig iron hub castings on DISA line and design method of riser and pouring system
CN101767189A (en) Method for simulating solid phase movement in steel ingot
CN113722964A (en) Casting simulation method
CN105787166B (en) A kind of loose prognosis modelling method of gross segregation shrinkage cavity in ingot casting
Wang et al. Optimal gating system design of steel casting by fruit fly optimization algorithm based on casting simulation technology
CN108393438A (en) The process unit and production method of Iron Mould Coated Sand vertical-parting cast bearing lid casting
CN108213342A (en) The casting technique of the complicated smallclothes of batch production
CN206229978U (en) The running and feeding system of gray cast iron Hub Castings casting is produced on DISA lines
Tian et al. Optimization of investment casting process parameters to reduce warpage of turbine blade platform in DD6 alloy
CN102921901A (en) Casting method for main shaft of wind generating set
CN108345737B (en) Design method of bloom continuous casting rotational flow water gap
CN110991093A (en) Casting simulation method for replacing heat-insulating riser with riser model
CN113239501B (en) Method for acquiring cross-sectional area calculation model of vertical pouring system and method for acquiring cross-sectional area
Nyemba et al. Optimization of the casting technology and sustainable manufacture of 100mm grinding balls for the mining Sector in Zimbabwe
Kimatsuka et al. Mold filling simulation with consideration of gas escape through sand mold
CN104014742A (en) Casting process and casting mould of large propeller hub body
CN206869028U (en) Lower open die reversely verts gravity casting mold on aluminium alloy outlet pipe

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant