CN105964990A

CN105964990A - Directional solidification method with external magnetic field for controlling freckle defect

Info

Publication number: CN105964990A
Application number: CN201610356362.3A
Authority: CN
Inventors: 秦岭; 沈军; 周雷; 李秋东
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2016-05-26
Filing date: 2016-05-26
Publication date: 2016-09-28
Anticipated expiration: 2036-05-26
Also published as: CN105964990B

Abstract

The invention provides a directional solidification method with an external magnetic field for controlling a freckle defect. The matched traveling wave magnetic field is exerted on a casting to control the solidification defect of freckles, and visual precision pre-control is carried out on the strength and direction of the traveling wave magnetic field and flowing of an alloy liquid phase on the basis of the numerical simulation technique. Through reliable pre-control analytical calculation, the acting direction and strength of the external traveling wave magnetic field capable of precisely restraining flowing are given out, liquid phase flowing at the front edge of a solid phase channel and a solidification interface can be weakened or eliminated, the purpose of eliminating the freckle defect is finally achieved, and the intractable problem that liquid phase flowing is hard to control in the existing casting directional solidification process is solved.

Description

A kind of externally-applied magnetic field controls the directional freeze method of freckle defect

Technical field

The present invention relates to directional solidification technique, a kind of externally-applied magnetic field controls the directional freeze method of freckle defect.

Background technology

It is owing to the method enables to that some metals and semi-conducting material all use directional solidification technique to be processed manufacture Solidified structure grows along specific direction.These crystal grain aligned eliminate horizontal crystal boundary, so that some are partly The photoelectric transformation efficiency of conductor material and the intensity of metal material, creep and persistency all produce and are substantially improved.But Often occurring some coagulation defects during directional solidification, e.g., crystal growth is the most straight and upright, and morphological element is uneven Deng.These defects have impact on the combination property of material to a certain extent.Additionally, also the solidification of an entitled freckle of class lacks Fall into the serious comprehensive mechanical property that have impact on metal material, such as, when this kind of defect occurs in single crystal super alloy whirlpool Scrapping of blade can be directly resulted in time on impeller blade.This kind of defect of freckle tends to occur in the alloy of multicomponent, e.g., Terne metal, high temperature alloy etc., and during the directional solidification of this kind of alloy, between solid phase and liquid phase, generally have one The region of individual solid-liquid two-phase coexistent, i.e. two-phase section.In two-phase section, discharge substantial amounts of solute unit near the region of solid phase Element, density is lower than the region of close liquid phase, therefore, creates the buoyancy acting in liquid phase.When liquid phase buoyancy is more than During viscous force, causing the interchannel liquid phase in solid phase to produce flowing, in this passage, the solute of the high concentration of flowing exists Channel interior finally solidifies, and forms " freckle " this kind of coagulation defect in foundry goods.

It is the most straight and upright that presently disclosed certain methods can be decreased or even eliminated crystal growth, and morphological element is uneven, freckle Deng coagulation defect.As, realize the control to Material Coagulating Process by externally-applied magnetic field, its medium and low frequency travelling-magnetic-field quilt During applying to quasiconductor and metal material processing and preparation.Invention in Patent No. CN201110007198.2 In patent, disclose a kind of device for directionally solidifying having traveling-wave magnetic field generator.This invention applies row ripple magnetic by outside Field produces Lorentz force in stannum cadmium alloy and directly acts on the crystal of growth, thus reaches to change crystal growth Purpose；And in the patent of invention of Patent No. CN201210059757.9, disclose a kind of raising czochralski silicon monocrystal The travelling-magnetic-field method of resistivity evenness.This invention can effectively suppress highly concentrated by the Lorentz force that travelling-magnetic-field produces The downward deposition problems of degree adulterant, reaches to improve the purpose of the uniformity of morphological element, thus it is heavily doped to improve vertical pulling The radial direction resistivity evenness of silicon single crystal；In the innovation and creation of Application No. 201610345111.5, it is proposed that a kind of Eliminate the method for freckle, the method graphite of definite shape size in the blade class directional solidification castings of cross section sudden change Block replaces the die casing material of local, foundry goods cross section Sudden change region, by the chilling action of graphite block, reduces in two-phase section The dendrite interval of solid phase, increases the resistance that liquid phase is flowed by solid phase passage, thus weakens or eliminate interchannel liquid Flow mutually, finally reduce or eliminate freckle.But the method can introduce while weakening in Quench or eliminating freckle New stray crystal, thus reduce the comprehensive mechanical property of foundry goods, foundry goods defines stray crystal defect.

In recent years, Chinese scholars research finds that travelling-magnetic-field can not only control the growth of crystal in alloy, raising group Knit composition uniformity, additionally it is possible to impact is such as the flowing in the liquid phases such as monocrystal silicon, aluminium copper, terne metal, high temperature alloy. Patent of the present invention is based on these notional results, it is proposed that utilize travelling-magnetic-field to produce Lorentz force in liquid metal, Offset the buoyancy in the solid phase passage in two-phase section and in the liquid phase in forward position, freezing interface, the passage in suppression two-phase section Flowing, it is to avoid the formation in high concentration enrichment of element district, fundamentally reaches to eliminate the purpose of freckle defect.In above-mentioned mistake Cheng Zhong, when travelling-magnetic-field intensity is excessive, its Lorentz force produced can make to introduce in liquid phase new flowing, but works as Travelling-magnetic-field is too small, and its Lorentz force produced can not be completely counterbalanced by again buoyancy.Therefore to reach to eliminate the mesh of freckle , need the control to travelling-magnetic-field direction and intensity to propose the most accurate requirement.Additionally, the flowing in liquid phase exists Can not directly be observed under existing experiment condition.

Summary of the invention

For overcome weaken in Quench or eliminate freckle present in prior art while can introduce new stray crystal, from And reduce the comprehensive mechanical property of foundry goods, and foundry goods defines the deficiency of stray crystal defect, the present invention proposes one Externally-applied magnetic field controls the directional freeze method of freckle defect.

The present invention comprises the concrete steps that:

Step 1, determines travelling-magnetic-field operating parameter.Freckle can be produced by the travelling-magnetic-field operating parameter regulation and control of coupling Flowing in the alloy liquid phase of defect.Wherein, travelling-magnetic-field operating parameter is respectively phase angle, current intensity and frequency； Complete to the directional solidification under travelling-magnetic-field effect by Ansys emag electromagnetic analysis software and Fluent fluid analysis software Process carries out the numerical simulation calculation analysis of multiple physical field coupling.Detailed process is:

The first step, generates the grid of the alloy-steel casting of the meeting generation freckle defect of simulation.

Second step, generates the grid of traveling wave line circle.

3rd step, generates the grid of directional solidification furnace chamber.

4th step, inputs the magnetic physical parameter of the magnetic physical parameter of the described alloy-steel casting that can produce freckle defect, formwork Magnetic physical parameter with coil.

5th step, calculates the electromagnetic force that travelling-magnetic-field produces.

6th step, the magnetic field in checking numerical simulation.

The process in the magnetic field in described checking numerical simulation is, arrange the electric current of travelling-magnetic-field device in experiment numerical value, The numerical value of frequency and the numerical value at phase angle and the numerical value of electric current in Ansys emag numerical simulation, the numerical value of frequency and phase The difference numerical value of parallactic angle is identical, and utilizes the magnetic field measuring instrument-Tesla meter of routine to measure space magnetic field.Will The measurement result obtained contrasts with analog result.If error is more than 5%, then comes back to the 4th step and adjust meter Calculate parameter until error carries out the 7th step after being less than 5%；If error is less than 5%, carry out the 7th step.Described Adjustable calculation Parameter is to reduce the value of relaxation factor in Ansys emag computed in software magnetic field process with the step-length of 0.1, after reducing The value input Ansys emag software of relaxation factor, that repeats the 5th step and the 6th step utilizes conventional detector for magnetic fields Space magnetic field is measured by device-Tesla meter, and the measurement result obtained is contrasted with analog result；If contrast Error carries out the 7th step less than 5%.If to ratio error more than 5%, continue to adjust coefficient of dispersion with the step-length of 0.1 Value；The value input Ansys emag software of the coefficient of dispersion after reducing, the utilization repeating the 5th step and the 6th step is conventional Magnetic field measuring instrument-Tesla meter space magnetic field is measured, and the measurement result obtained is carried out with analog result Contrast；If to ratio error less than 5%, carrying out the 7th step.If to ratio error more than 5%, repeat described Adjustable calculation ginseng The process of number, adjusts the value of relaxation factor and the value of coefficient of dispersion the most respectively until described measurement result and analog result Error less than 5%.

7th step, inputs the thermal physical property parameter of foundry goods, the thermal physical property parameter of formwork and the 5th step in Fluent software In the electromagnetic force that obtains.

The described thermal physical property parameter of the alloy that can produce freckle defect and the thermal physical property parameter of formwork each mean that this foundry goods is solidifying The heat conduction at different temperatures of thermal conductivity, viscosity, density, latent heat of solidification, thermal coefficient of expansion and formwork during Gu Rate.

8th step, determine described can produce freckle defect alloy directionally solidified during boundary condition.

9th step, sets the withdrawing rate of the described alloy-steel casting that can produce freckle defect and the initial of directional solidification process Condition.

The withdrawing rate of the described alloy-steel casting that can produce freckle defect and the initial condition of directional solidification process refer to this The heating-up temperature of the described alloy-steel casting that can produce freckle defect and withdrawing rate.Described heating-up temperature is described meeting Produce the fusion temperature of the alloy of freckle defect；Described withdrawing rate is 90～120 μm/s.

Tenth step, determines so that the travelling-magnetic-field parameter of the described alloy liquid phase flowing minimum that can produce freckle defect.Adopt With the mobility status of alloy liquid phase under Fluent fluid analysis computed in software travelling-magnetic-field effect, the different travelling-magnetic-field of contrast Under the conditions of the mobility status that calculates, and obtain the travelling-magnetic-field parameter making flowing minimum.Described at calculating row ripple Under the action of a magnetic field during the mobility status of the described alloy liquid phase that can produce freckle defect, obtain not by solving N-S equation With the change curve of liquid phase flow rate size during directional solidification under magnetic field intensity.In calculating, when described alloy is slicker solder During alloy, current settings is 10～22A, frequency setting is 20～50Hz, and magnetic field intensity is 10mT；When described conjunction When gold is nickel base superalloy, current settings is 22～27A, frequency is 50Hz, and magnetic field intensity is 24～28.5mT. So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is lacked by crystallizer and the described freckle that can produce The alloy liquid metal composition fallen into, and formwork is vertically fixed on pumping rod end.

Step 4, evacuation: mechanical pump is evacuated to below 4Pa, close applying argon gas after mechanical valve.

Step 5, heats melted alloy: the simple substance raw material that will melt by national standard proportioning and loads fusion crucible Middle fusing, obtains the described alloy that can produce freckle defect.When described alloy is terne metal, lead raw material and stannum Raw material presses lead: the mass fraction ratio of stannum=67:33.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching to state the alloy melting temperature that can produce freckle defect.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil is fixed on conventional directional solidification The load coil of equipment is peripheral, and makes the center of circle of load coil and travelling-magnetic-field coil ensure to overlap.

Step 8, casting and pull: the alloy melt that the meeting of fusing produces in step 6 freckle defect is poured into formwork In.Setting withdrawing rate as 20～80 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, it is right to complete The pull of terne metal.Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Gear is stopped after insulation 15min Oil pump, stops water pump cooling after graphite cannula temperature is less than 150 DEG C, obtains the alloy-steel casting without producing freckle defect.

The core of the present invention is that the travelling-magnetic-field applying coupling controls this kind of coagulation defect of freckle, and based on numerical simulation skill The art intensity to travelling-magnetic-field, the flowing in direction and alloy liquid phase carries out visual accurate pre-control.By the most pre- Control analytical calculation, provides direction and the intensity of the effect of the external travelling-magnetic-field that can accurately suppress flowing, it is achieved weaken Or the liquid phase eliminating solid phase passage and forward position, freezing interface flows, and it is finally reached the purpose eliminating freckle defect.

The present invention is by the flowing in external travelling-magnetic-field suppression solid liquid interface forward position, thus effectively reduces generation segregation The probability of passage, it is to avoid the formation of regional area freckle defect.Numerical-Mode based on multiple physical field coupling in the process Plan technology carries out visual pre-control to the flowing in the intensity of travelling-magnetic-field and alloy liquid phase, to promote suppression defect Effect.Knowable to literature search, there is not yet the report being controlled freckle defect by travelling-magnetic-field the most both at home and abroad.

After the sample obtaining the present invention carries out macrocorrosion, it can be seen that use the downward travelling-magnetic-field loading coupling There is not this kind of defect of freckle in rear cast-internal.Illustrate that above-mentioned technique can lack as freckle during controlling directional solidification Fall into the method formed.

The present invention is applicable to terne metal or CMSX-4 or CMSX-10 or CM247LC or DZ125 or DZ411 or DD6 Or DD9 or DD98 or DD10 or PWA1484 or ReneN5 or ReneN6 nickel base superalloy.

Compared with prior art, the invention has the beneficial effects as follows:

During the present invention solves existing foundry goods directional solidification, liquid phase flowing is difficult to control to this intractable problem.The party Method regulates and controls liquid phase by external travelling-magnetic-field and flows, thus effectively reduces the probability producing segregation passage at this, Avoid regional area and form the defects such as freckle, it is ensured that without orientation crystalline substance or the system of single crystal casting of (lacking) freckle defect Make.The operating parameter of travelling-magnetic-field is carried out visualizing pre-control, therefore this technical process by result based on finite element analysis More accurate than traditional handicraft.In the analog result of electromagnetic field, as shown in Figure 2 a when phase angle be ordered as-120 °, 0 ° ,-240 °, travelling-magnetic-field produces Lorentz force upwards in the liquid phase；It is ordered as when phase angle as shown in Figure 2 b 0 ° ,-120 ° ,-240 °, travelling-magnetic-field produces downward Lorentz force in the liquid phase.In the analog result in flow field, As shown in Figure 3 a when applying travelling-magnetic-field upwards, the free convection intensity in solid liquid interface forward position increases along with magnetic field intensity Aggravate by force.As shown in Figure 3 b when applying downward travelling-magnetic-field, magnetic field intensity is solid liquid interface when below 10mT Weaken greatly in the free convection in forward position.As illustrated in fig. 4 d and 4e, when applying the downward travelling-magnetic-field of 10mT, Freckle defect does not all occur in foundry goods.But, when applying the travelling-magnetic-field upwards of varying strength, the passeris montani saturati in foundry goods Speckle defect but can't eliminate.Fig. 4 b and Fig. 4 c is shown that loading the upwards travelling-magnetic-field of 8mT and 15mT respectively Foundry goods macrostructure figure, find create freckle defect equally in foundry goods edge.Illustrate in apparatus for directional solidification External unmatched travelling-magnetic-field, the freckle defect of cast-internal can't eliminate.

Accompanying drawing explanation

Fig. 1 is the structural representation of the device for directionally solidifying of built-in traveling-wave magnetic field generator；

Fig. 2 is the Lorentz force distributing vector figure under the travelling-magnetic-field effect obtained by method for numerical simulation in sample； Wherein: Fig. 2 (a) is Lorentz force distribution upwards, Fig. 2 (b) is downward Lorentz force distribution；

In face of the varying strength travelling-magnetic-field effect lower bound that Fig. 3 is obtained by method for numerical simulation, the mean flow rate on edge changes Curve: wherein: Fig. 3 (a) is Lorentz force upwards, and Fig. 3 (b) is downward Lorentz force；

Fig. 4 is the macrostructure of freezing interface under different condition；Wherein: a. free convection, b.I=10A, f=50Hz, B=10mT, phase angle sequence-120 °, 0 ° ,-240 ° of c.I=20A, f=50Hz, B=24mT, phase angle is arranged Sequence-120 °, 0 ° ,-240 °, d.I=10A, f=50Hz, B=10mT, phase angle sort 0 ° ,-120 ° ,-240 °, e.I=18A, f=30Hz, B=10mT, sort 0 ° ,-120 ° ,-240 ° in phase angle；In figure, I is electric current, f For frequency, B is magnetic field intensity.

Fig. 5 is the flow chart of the present invention.In accompanying drawing:

1. travelling-magnetic-field coil；2. load coil；3. freckle defect.

Detailed description of the invention

Embodiment one

The present embodiment is a kind of directional freeze method controlling freckle defect, specifically comprises the following steps that

Step 1, determines travelling-magnetic-field operating parameter.Freckle can be produced by the travelling-magnetic-field operating parameter regulation and control of coupling Flowing in the alloy liquid phase of defect.Wherein, travelling-magnetic-field operating parameter is respectively phase angle, current intensity and frequency； Complete to the directional solidification under travelling-magnetic-field effect by Ansys emag electromagnetic analysis software and Fluent fluid analysis software Process carries out the numerical simulation calculation analysis of multiple physical field coupling.In the present embodiment, the described conjunction that can produce freckle defect Gold is terne metal.

The detailed process determining travelling-magnetic-field operating parameter is:

The first step, generates the grid of the foundry goods of simulation.Conventional tetrahedral grid division methods is used to carry out the net of foundry goods Lattice divide, and obtain the grid model of this foundry goods.Check mistake that may be present in the grid of described foundry goods；Described mistake Include that negative volume or grid node intersect by mistake；If there is described mistake, then re-start the stress and strain model of foundry goods；If nothing Mistake then carries out second step；

Second step, generates the grid of traveling wave line circle.Conventional tetrahedral grid division methods is used to carry out traveling wave line circle Stress and strain model, obtains the grid model of this traveling wave line circle.Check mistake that may be present in the grid of described traveling wave line circle； Described mistake includes that negative volume or grid node intersect；If there is described mistake, then re-start the net of traveling wave line circle Lattice divide；If inerrancy, carry out the 3rd step；

3rd step, generates the grid of directional solidification furnace chamber.When making inner chamber, conventional tetrahedral grid is used to draw Point method carries out the stress and strain model of inner chamber, obtains the grid model of this inner chamber.Check in the grid of described inner chamber and may deposit Mistake；Described mistake includes that negative volume or grid node intersect；If there is described mistake, then in re-starting The stress and strain model in chamber；If inerrancy, carry out the 4th step；

4th step, inputs the magnetic physical parameter of foundry goods, the magnetic physical parameter of formwork and coil in Ansys emag software Magnetic physical parameter, described magnetic physical parameter is that this foundry goods obtained by normal experiment method is in process of setting Relative permeability, pcrmeability and resistivity.Relaxation factor during Ansys emag computed in software magnetic field and discrete The simulation result of calculation in magnetic field is had a significant impact, initially with default value by coefficient.

5th step, the electromagnetic force produced by Ansys emag computed in software travelling-magnetic-field, and exported by txt form.

6th step, the magnetic field in checking numerical simulation.The process in the magnetic field in described checking numerical simulation is to arrange reality The numerical value at the numerical value of electric current of the travelling-magnetic-field device in testing, the numerical value of frequency and phase angle and Ansys emag Numerical-Mode The numerical value of the electric current in plan, frequency numerical value identical with the difference numerical value at phase angle, and utilize routine detector for magnetic fields Space magnetic field is measured by device-Tesla meter.The measurement result obtained is contrasted with analog result.If error is big In 5%, then come back to the 4th step Adjustable calculation parameter until error carries out the 7th step after being less than 5%；If error is little The 7th step is carried out in 5%.Described Adjustable calculation parameter is to reduce Ansys emag computed in software magnetic with the step-length of 0.1 The value of the relaxation factor during Chang, the value input Ansys emag software of the relaxation factor after reducing, repeats the 5th Space magnetic field is measured by the conventional magnetic field measuring instrument-Tesla meter that utilizes of step and the 6th step, and the survey that will obtain Amount result contrasts with analog result；If to ratio error less than 5%, carrying out the 7th step.If to ratio error more than 5 % then continues to adjust the value of coefficient of dispersion with the step-length of 0.1；The value input Ansys emag of the coefficient of dispersion after reducing Software, space magnetic field is surveyed by the conventional magnetic field measuring instrument-Tesla meter that utilizes repeating the 5th step and the 6th step Amount, and the measurement result obtained is contrasted with analog result；If to ratio error less than 5%, carrying out the 7th step. If to ratio error more than 5%, repeating the process of described Adjustable calculation parameter, adjust the most respectively relaxation factor value and The value of coefficient of dispersion is until the error of described measurement result and analog result is less than 5%.

7th step, inputs the thermal physical property parameter of foundry goods, the thermal physical property parameter of formwork and the 5th step in Fluent software In the electromagnetic force that obtains, the thermal physical property parameter of described foundry goods and the thermal physical property parameter of formwork each mean that this foundry goods was solidifying Thermal conductivity, viscosity, density, latent heat of solidification, thermal coefficient of expansion and formwork in journey thermal conductivity at different temperatures. The thermal physical property parameter of described foundry goods and the thermal physical property parameter of formwork are obtained by normal experiment method.

8th step, determines the boundary condition during directional solidification.Described boundary condition includes between formwork and foundry goods Heat transfer coefficient, the emissivity of described directional solidification furnace chamber and the temperature of this directional solidification furnace chamber zones of different. The value of described heat transfer coefficient refers under the conditions of steady heat transfer, and this foundry goods and both sides, formwork interface Air Temperature Difference are 1 DEG C Time, pass through 1m in 1s²The heat of area transmission, the unit of this heat transfer coefficient is W/m²·℃.Described directional solidification The zones of different of furnace chamber refers to the thermal treatment zone of this directional solidification furnace chamber, thermal insulation board district and cooling zone；

9th step, sets withdrawing rate and the initial condition of directional solidification process of foundry goods.Described initial condition refers to Heating-up temperature and withdrawing rate to foundry goods.Described heating-up temperature is the fusion temperature of described terne metal；Described Withdrawing rate be 20 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 10A, frequency is 50Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 10mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork: the conventional method prepared based on moltening mold castings formwork and the physical dimension manufacture of foundry goods Formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is made up of crystallizer and liquid metal, And formwork is vertically fixed on pumping rod end.

Step 5, heats melted alloy: the lead raw material that will melt and stannum raw material are by lead: the quality of stannum=67:33 Score ratio loads in fusion crucible, opens circulation waterway the power-on fusing of induction heating power, obtains slicker solder and close Gold.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching terne metal fusion temperature.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil 2 and travelling-magnetic-field coil 1 ensures Overlap.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, outfan respectively Mouth b and output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ends The phase angle of mouth, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.Will Three circle coils are respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.This enforcement Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil by example, it is possible at terne metal The Lorentz force that direction is downward is produced in liquid phase.Open magnetic field special variable-frequency power sources, adjust knob on control panel with Acquisition electric current is 10A and frequency is 50Hz, also needs to open gear oil pump simultaneously and carries out cold to traveling-wave magnetic field generator But.

Step 8, casting and pull: in step 6, the terne metal melt of fusing will be poured in formwork.Set pull Speed is 20 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes the pull to terne metal. Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after being incubated at least 15min, treat graphite Sleeving temperature stops water pump cooling after being less than 150 DEG C, obtain terne metal foundry goods.

Observe the terne metal foundry goods macrostructure figure that the present embodiment obtains, it can be seen that apply specific direction and intensity row The foundry goods in ripple magnetic field does not occurs this kind of coagulation defect of freckle.Comparison diagram 4a and 4d finds, is not applying travelling-magnetic-field Under conditions of create freckle defect in foundry goods center；And be 10A at given row wave producer electric current, frequency is The phase angle of 50Hz and three circle coils be from top to bottom ordered as 0 ° ,-120 ° ,-240 ° time, foundry goods does not occurs This kind of coagulation defect of freckle.

Embodiment two

9th step, sets withdrawing rate and the initial condition of directional solidification process of foundry goods.Described initial condition refers to Heating-up temperature and withdrawing rate to foundry goods.Described heating-up temperature is the fusion temperature of described terne metal；Described Withdrawing rate be 35 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 22A, frequency is 20Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 10mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil and travelling-magnetic-field coil 1 ensures weight Close.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, output port b respectively With output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ports Phase angle, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.By three circles Coil is respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.In the present embodiment Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil, it is possible in terne metal liquid phase The Lorentz force that interior generation direction is downward.Open the special variable-frequency power sources in magnetic field, adjust the knob on control panel to obtain Electric current is 22A and frequency is 20Hz, also needs to open gear oil pump simultaneously and cools down traveling-wave magnetic field generator.

Step 8, casting and pull: in step 6, the terne metal melt of fusing will be poured in formwork.Set pull Speed is 35 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes the pull to terne metal. Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat graphite cannula temperature Degree stops water pump cooling after being less than 150 DEG C, obtain terne metal foundry goods.

Observe the terne metal foundry goods macrostructure figure that the present embodiment obtains, it can be seen that apply specific direction and intensity row The foundry goods in ripple magnetic field does not occurs this kind of coagulation defect of freckle.Comparison diagram 4a and 4e finds, is not applying travelling-magnetic-field Under conditions of create freckle defect in foundry goods center；And be 22A at given row wave producer electric current, frequency is The phase angle of 20Hz and three circle coils be from top to bottom ordered as 0 ° ,-120 ° ,-240 ° time, foundry goods does not occurs This kind of coagulation defect of freckle.

Embodiment three

9th step, sets withdrawing rate and the initial condition of directional solidification process of foundry goods.Described initial condition refers to Heating-up temperature and withdrawing rate to foundry goods.Described heating-up temperature is the fusion temperature of described terne metal；Described Withdrawing rate be 80 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 15A, frequency is 36.5Hz；The phase angle of three circle coils of travelling-magnetic-field is by upper Be ordered as under to 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 10mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil 2 and travelling-magnetic-field coil 1 ensures Overlap.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, outfan respectively Mouth b and output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ends The phase angle of mouth, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.Will Three circle coils are respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.This enforcement Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil by example, it is possible at terne metal The Lorentz force that direction is downward is produced in liquid phase.Open magnetic field special variable-frequency power sources, adjust knob on control panel with Acquisition electric current is 15A and frequency is 36.5Hz, also needs to open gear oil pump simultaneously and carries out cold to traveling-wave magnetic field generator But.

Step 8, casting and pull: in step 6, the terne metal melt of fusing will be poured in formwork.Set pull Speed is 80 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes the pull to terne metal. Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat graphite cannula temperature Degree stops water pump cooling after being less than 150 DEG C, obtain terne metal foundry goods.

Embodiment four

Step 1, determines travelling-magnetic-field operating parameter.Freckle can be produced by the travelling-magnetic-field operating parameter regulation and control of coupling Flowing in the alloy liquid phase of defect.Wherein, travelling-magnetic-field operating parameter is respectively phase angle, current intensity and frequency； Complete to the directional solidification under travelling-magnetic-field effect by Ansys emag electromagnetic analysis software and Fluent fluid analysis software Process carries out the numerical simulation calculation analysis of multiple physical field coupling.The described alloy that can produce freckle defect is nickel-base high-temperature CMSX-4 alloy in alloy or CMSX-10 or CM247LC or DZ125 or DZ411 or DD6 or DD9 or DD98 Or DD10 or PWA1484 or ReneN5 or Rene N6.

In the present embodiment, it is been described by as a example by CMSX-4 nickel base superalloy.

The first step, generates the grid of the CMSX-4 alloy-steel casting of simulation.Use conventional tetrahedral grid division methods Carry out the stress and strain model of CMSX-4 alloy-steel casting, obtain the grid model of this CMSX-4 alloy-steel casting.Check described Mistake that may be present in the grid of CMSX-4 alloy-steel casting；Described mistake includes that negative volume or grid node intersect； If there is described mistake, then re-start the stress and strain model of CMSX-4 alloy-steel casting；If inerrancy, carry out second step；

7th step, inputs the hot physical property ginseng of the thermal physical property parameter of CMSX-4 alloy-steel casting, formwork in Fluent software The electromagnetic force obtained in number and the 5th step, the thermal physical property parameter of described CMSX-4 alloy-steel casting and the hot physical property of formwork Parameter each means this CMSX-4 alloy-steel casting thermal conductivity in process of setting, viscosity, density, latent heat of solidification, heat The coefficient of expansion and formwork thermal conductivity at different temperatures.The thermal physical property parameter of described CMSX-4 alloy-steel casting and formwork Thermal physical property parameter obtained by normal experiment method.

8th step, determines the boundary condition during directional solidification.Described boundary condition includes formwork and CMSX-4 Heat transfer coefficient, the emissivity of described directional solidification furnace chamber and this directional solidification furnace chamber between alloy-steel casting are different The temperature in region.The value of described heat transfer coefficient refers under the conditions of steady heat transfer, this CMSX-4 alloy-steel casting and mould When both sides, shell interface Air Temperature Difference is 1 DEG C, in 1s, pass through 1m²The heat of area transmission, the unit of this heat transfer coefficient is W/m²·℃.The zones of different of described directional solidification furnace chamber refers to the thermal treatment zone of this directional solidification furnace chamber, thermal insulation board District and cooling zone；

9th step, sets withdrawing rate and the initial condition of directional solidification process of CMSX-4 alloy-steel casting.Described Initial condition refers to the heating-up temperature to CMSX-4 alloy-steel casting and withdrawing rate.Described heating-up temperature is described The fusion temperature of CMSX-4 alloy；Described withdrawing rate is 20 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 22A, frequency is 50Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 24mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork: the conventional method prepared based on moltening mold castings formwork and CMSX-4 alloy-steel casting several What size manufactures formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is by crystallizer and CMSX-4 aluminium alloy State metal forms, and formwork is vertically fixed on pumping rod end.

Step 5, heats melted alloy: the raw material that will melt is loaded in fusion crucible as after GB proportioning, opens The circulation waterway of induction heating power power-on fusing, obtain CMSX-4 alloy.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching CMSX-4 alloy melting temperature.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil 2 and travelling-magnetic-field coil 1 ensures Overlap.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, outfan respectively Mouth b and output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ends The phase angle of mouth, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.Will Three circle coils are respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.This enforcement Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil by example, it is possible at terne metal The Lorentz force that direction is downward is produced in liquid phase.Open magnetic field special variable-frequency power sources, adjust knob on control panel with Acquisition electric current is 22A and frequency is 50Hz, also needs to open gear oil pump simultaneously and carries out cold to traveling-wave magnetic field generator But.

Step 8, casting and pull: in step 6, the CMSX-4 alloy melt of fusing will be poured in formwork.Set Withdrawing rate is 20 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes CMSX-4 alloy Pull.Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat Graphite cannula temperature stops water pump cooling after being less than 150 DEG C, obtain CMSX-4 alloy-steel casting.

Embodiment five

In the present embodiment, it is been described by as a example by DZ125 nickel base superalloy.

The first step, generates the grid of the DZ125 alloy-steel casting of simulation.Conventional tetrahedral grid division methods is used to enter The stress and strain model of row DZ125 alloy-steel casting, obtains the grid model of this DZ125 alloy-steel casting.Check described DZ125 Mistake that may be present in the grid of alloy-steel casting；Described mistake includes that negative volume or grid node intersect；If occurring Described mistake, then re-start the stress and strain model of DZ125 alloy-steel casting；If inerrancy, carry out second step；

7th step, inputs the thermal physical property parameter of DZ125 alloy-steel casting, the thermal physical property parameter of formwork in Fluent software And the 5th electromagnetic force obtained in step, the thermal physical property parameter of described DZ125 alloy-steel casting and the thermal physical property parameter of formwork Each mean this DZ125 alloy-steel casting thermal conductivity in process of setting, viscosity, density, latent heat of solidification, thermal expansion system Number and formwork thermal conductivity at different temperatures.The thermal physical property parameter of described DZ125 alloy-steel casting and the hot physical property of formwork Parameter is obtained by normal experiment method.

8th step, determines the boundary condition during directional solidification.Described boundary condition includes that formwork closes with DZ125 Heat transfer coefficient, the emissivity of described directional solidification furnace chamber and this directional solidification furnace chamber difference district between gold foundry goods The temperature in territory.The value of described heat transfer coefficient refers under the conditions of steady heat transfer, this DZ125 alloy-steel casting and formwork circle When both sides, face Air Temperature Difference is 1 DEG C, in 1s, pass through 1m²The heat of area transmission, the unit of this heat transfer coefficient is W/m²·℃.The zones of different of described directional solidification furnace chamber refers to the thermal treatment zone of this directional solidification furnace chamber, thermal insulation board District and cooling zone；

9th step, sets withdrawing rate and the initial condition of directional solidification process of DZ125 alloy-steel casting.At the beginning of described Beginning condition refers to the heating-up temperature to DZ125 alloy-steel casting and withdrawing rate.Described heating-up temperature is described DZ125 The fusion temperature of alloy；Described withdrawing rate is 40 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 24A, frequency is 50Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 26mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork: the conventional method prepared based on moltening mold castings formwork and DZ125 alloy-steel casting several What size manufactures formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is by crystallizer and DZ125 alloy liquid Metal forms, and formwork is vertically fixed on pumping rod end.

Step 5, heats melted alloy: the raw material that will melt is loaded in fusion crucible as after GB proportioning, opens The circulation waterway of induction heating power power-on fusing, obtain DZ125 alloy.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching DZ125 alloy melting temperature.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil and travelling-magnetic-field coil 1 ensures weight Close.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, output port b respectively With output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ports Phase angle, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.By three circles Coil is respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.In the present embodiment Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil, it is possible in terne metal liquid phase The Lorentz force that interior generation direction is downward.Open the special variable-frequency power sources in magnetic field, adjust the knob on control panel to obtain Electric current is 24A and frequency is 50Hz, also needs to open gear oil pump simultaneously and cools down traveling-wave magnetic field generator.

Step 8, casting and pull: in step 6, the DZ125 alloy melt of fusing will be poured in formwork.Setting is taken out Pulling rate rate is 40 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes to take out DZ125 alloy Draw.Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat graphite Sleeving temperature stops water pump cooling after being less than 150 DEG C, obtain DZ125 alloy-steel casting.

Embodiment six

In the present embodiment, it is been described by as a example by ReneN5 nickel base superalloy.

The first step, generates the grid of the ReneN5 alloy-steel casting of simulation.Conventional tetrahedral grid division methods is used to enter The stress and strain model of row ReneN5 alloy-steel casting, obtains the grid model of this ReneN5 alloy-steel casting.Check described ReneN5 Mistake that may be present in the grid of alloy-steel casting；Described mistake includes that negative volume or grid node intersect；If occurring Described mistake, then re-start the stress and strain model of ReneN5 alloy-steel casting；If inerrancy, carry out second step；

7th step, inputs the thermal physical property parameter of ReneN5 alloy-steel casting, the thermal physical property parameter of formwork in Fluent software And the 5th electromagnetic force obtained in step, the thermal physical property parameter of described ReneN5 alloy-steel casting and the thermal physical property parameter of formwork Each mean this ReneN5 alloy-steel casting thermal conductivity in process of setting, viscosity, density, latent heat of solidification, thermal expansion system Number and formwork thermal conductivity at different temperatures.The thermal physical property parameter of described ReneN5 alloy-steel casting and the hot physical property of formwork Parameter is obtained by normal experiment method.

8th step, determines the boundary condition during directional solidification.Described boundary condition includes formwork and ReneN5 Heat transfer coefficient, the emissivity of described directional solidification furnace chamber and this directional solidification furnace chamber between alloy-steel casting are different The temperature in region.The value of described heat transfer coefficient refers under the conditions of steady heat transfer, this ReneN5 alloy-steel casting and formwork When both sides, interface Air Temperature Difference is 1 DEG C, in 1s, pass through 1m²The heat of area transmission, the unit of this heat transfer coefficient is W/m²·℃.The zones of different of described directional solidification furnace chamber refers to the thermal treatment zone of this directional solidification furnace chamber, thermal insulation board District and cooling zone；

9th step, sets withdrawing rate and the initial condition of directional solidification process of ReneN5 alloy-steel casting.At the beginning of described Beginning condition refers to the heating-up temperature to ReneN5 alloy-steel casting and withdrawing rate.Described heating-up temperature is described The fusion temperature of ReneN5 alloy；Described withdrawing rate is 60 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 26A, frequency is 50Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 27mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork: the conventional method prepared based on moltening mold castings formwork and ReneN5 alloy-steel casting several What size manufactures formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is by crystallizer and ReneN5 alloy liquid Metal forms, and formwork is vertically fixed on pumping rod end.

Step 5, heats melted alloy: the raw material that will melt is loaded in fusion crucible as after GB proportioning, opens The circulation waterway of induction heating power power-on fusing, obtain ReneN5 alloy.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching ReneN5 alloy melting temperature.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil 2 and travelling-magnetic-field coil 1 ensures Overlap.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, outfan respectively Mouth b and output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ends The phase angle of mouth, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.Will Three circle coils are respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.This enforcement Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil by example, it is possible at terne metal The Lorentz force that direction is downward is produced in liquid phase.Open magnetic field special variable-frequency power sources, adjust knob on control panel with Acquisition electric current is 26A and frequency is 50Hz, also needs to open gear oil pump simultaneously and carries out cold to traveling-wave magnetic field generator But.

Step 8, casting and pull: in step 6, the ReneN5 alloy melt of fusing will be poured in formwork.Setting is taken out Pulling rate rate is 60 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes to take out ReneN5 alloy Draw.Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat graphite Sleeving temperature stops water pump cooling after being less than 150 DEG C, obtain ReneN5 alloy-steel casting.

Embodiment seven

In the present embodiment, it is been described by as a example by PWA1484 nickel base superalloy.

The first step, generates the grid of the PWA1484 alloy-steel casting of simulation.Use conventional tetrahedral grid division methods Carry out the stress and strain model of PWA1484 alloy-steel casting, obtain the grid model of this PWA1484 alloy-steel casting.Check described Mistake that may be present in the grid of PWA1484 alloy-steel casting；Described mistake includes that negative volume or grid node intersect； If there is described mistake, then re-start the stress and strain model of PWA1484 alloy-steel casting；If inerrancy, carry out second step；

7th step, inputs the hot physical property ginseng of the thermal physical property parameter of PWA1484 alloy-steel casting, formwork in Fluent software The electromagnetic force obtained in number and the 5th step, the thermal physical property parameter of described PWA1484 alloy-steel casting and the hot physical property of formwork Parameter each means this PWA1484 alloy-steel casting thermal conductivity in process of setting, viscosity, density, latent heat of solidification, heat The coefficient of expansion and formwork thermal conductivity at different temperatures.The thermal physical property parameter of described PWA1484 alloy-steel casting and formwork Thermal physical property parameter obtained by normal experiment method.

8th step, determines the boundary condition during directional solidification.Described boundary condition includes formwork and PWA1484 Heat transfer coefficient, the emissivity of described directional solidification furnace chamber and this directional solidification furnace chamber between alloy-steel casting are different The temperature in region.The value of described heat transfer coefficient refers under the conditions of steady heat transfer, this PWA1484 alloy-steel casting and mould When both sides, shell interface Air Temperature Difference is 1 DEG C, in 1s, pass through 1m²The heat of area transmission, the unit of this heat transfer coefficient is W/m²·℃.The zones of different of described directional solidification furnace chamber refers to the thermal treatment zone of this directional solidification furnace chamber, thermal insulation board District and cooling zone；

9th step, sets withdrawing rate and the initial condition of directional solidification process of PWA1484 alloy-steel casting.Described Initial condition refers to the heating-up temperature to PWA1484 alloy-steel casting and withdrawing rate.Described heating-up temperature is described The fusion temperature of PWA1484 alloy；Described withdrawing rate is 80 μm/s.

Tenth step, determines the travelling-magnetic-field parameter minimum so that alloy liquid phase flowing.Use Fluent fluid analysis software Calculate the mobility status of alloy liquid phase under travelling-magnetic-field effect, the flowing calculated under contrast different rows ripple magnetic field condition Situation, and obtain the travelling-magnetic-field parameter making flowing minimum.Described calculating alloy liquid phase under travelling-magnetic-field effect During mobility status, obtain under different magnetic field intensity liquid phase flow rate size during directional solidification by solving N-S equation Change curve.Setup algorithm electric current is 27A, frequency is 50Hz；The phase angle of three circle coils of travelling-magnetic-field is by up to Under be ordered as 0 ° ,-120 ° ,-240 ° time, the Lorentz force direction that travelling-magnetic-field produces in alloy liquid phase is downward, And magnetic field intensity is 28.5mT.Now can significantly suppress flowing.So far, travelling-magnetic-field operating parameter is obtained.

Step 2, prepares formwork: the conventional method prepared based on moltening mold castings formwork and PWA1484 alloy-steel casting Physical dimension manufactures formwork.

Step 3, die-filling shell: in vacuum hearth by be placed on the thermal insulation board in centre position whole region is divided into hot-zone and Cold-zone two parts.Hot-zone is made up of graphite heating body and induction coil, and cold-zone is by crystallizer and PWA1484 aluminium alloy State metal forms, and formwork is vertically fixed on pumping rod end.

Step 5, heats melted alloy: the raw material that will melt is loaded in fusion crucible as after GB proportioning, opens The circulation waterway of induction heating power power-on fusing, obtain PWA1484 alloy.

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered.It is stepped up Supply voltage is until temperature is incubated after reaching PWA1484 alloy melting temperature.

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil 1 is fixed on conventional orientation solidifying Fixed standby load coil 2 is peripheral, and ensures that the center of circle of load coil 2 and travelling-magnetic-field coil 1 ensures Overlap.The variable-frequency power sources applying travelling-magnetic-field use has 3 output ports, is output port a, outfan respectively Mouth b and output port c；Phase contrast between each output port is 120 °.Oscillograph is used to detect described 3 ends The phase angle of mouth, then having output port a is 0 °, and output port b is-120 °, and output port c is-240 °.Will Three circle coils are respectively connected to three ports of variable-frequency power sources upper, middle and lower, it is possible to obtain the travelling-magnetic-field of different directions.This enforcement Three described output ports are respectively connected to upper, middle and lower three circle travelling-magnetic-field coil by example, it is possible at terne metal The Lorentz force that direction is downward is produced in liquid phase.Open magnetic field special variable-frequency power sources, adjust knob on control panel with Acquisition electric current is 27A and frequency is 50Hz, also needs to open gear oil pump simultaneously and carries out cold to traveling-wave magnetic field generator But.

Step 8, casting and pull: in step 6, the PWA1484 alloy melt of fusing will be poured in formwork.Set Withdrawing rate is 80 μm/s, by pumping rod, by hot-zone, formwork is sent into cold-zone subsequently, completes PWA1484 alloy Pull.Stop pull；Stop insulation power supply and travelling-magnetic-field power supply.Stop gear oil pump after insulation 15min, treat Graphite cannula temperature stops water pump cooling after being less than 150 DEG C, obtain PWA1484 alloy-steel casting.

Claims

1. the directional freeze method of an externally-applied magnetic field control freckle defect, it is characterised in that comprise the concrete steps that:

Step 1, determines travelling-magnetic-field operating parameter: can produce freckle by the travelling-magnetic-field operating parameter regulation and control of coupling and lack Flowing in the alloy liquid phase fallen into；Wherein, travelling-magnetic-field operating parameter is respectively phase angle, current intensity and frequency； By Ansys emag electromagnetic analysis software and Fluent fluid analysis software, the orientation under travelling-magnetic-field effect is coagulated Gu overall process carries out the numerical simulation calculation analysis of multiple physical field coupling；Detailed process is:

The first step, generates the grid of the alloy-steel casting of the meeting generation freckle defect of simulation；

Second step, generates the grid of traveling wave line circle；

3rd step, generates the grid of directional solidification furnace chamber；

4th step, input the magnetic physical parameter of the described alloy-steel casting that can produce freckle defect, the magnetic physical parameter of formwork and The magnetic physical parameter of coil；

5th step, calculates the electromagnetic force that travelling-magnetic-field produces；

6th step, the magnetic field in checking numerical simulation；

7th step, inputs in the thermal physical property parameter of foundry goods, the thermal physical property parameter of formwork and the 5th step in Fluent software The electromagnetic force obtained；

8th step, determine described can produce freckle defect alloy directionally solidified during boundary condition；

9th step, sets withdrawing rate and the initial strip of directional solidification process of the described alloy-steel casting that can produce freckle defect Part；

Tenth step, determines so that the travelling-magnetic-field parameter of the described alloy liquid phase flowing minimum that can produce freckle defect；Use The mobility status of alloy liquid phase under Fluent fluid analysis computed in software travelling-magnetic-field effect, the different travelling-magnetic-field of contrast Under the conditions of the mobility status that calculates, and obtain the travelling-magnetic-field parameter making flowing minimum；Described at calculating row Under ripple the action of a magnetic field during the mobility status of the described alloy liquid phase that can produce freckle defect, by solving N-S equation Obtain under different magnetic field intensity the change curve of liquid phase flow rate size during directional solidification；So far, row ripple magnetic is obtained Field operating parameter；

Step 2, prepares formwork；

Step 3, die-filling shell: whole region is divided into hot-zone and cold by being placed on the thermal insulation board in centre position in vacuum hearth District's two parts；Hot-zone is made up of graphite heating body and induction coil, and cold-zone is lacked by crystallizer and the described freckle that can produce The alloy liquid metal composition fallen into, and formwork is vertically fixed on pumping rod end；

Step 4, evacuation: mechanical pump is evacuated to below 4Pa, close applying argon gas after mechanical valve；

Step 5, heats melted alloy: the simple substance raw material that will melt by national standard proportioning and loads in fusion crucible Fusing, obtains the described alloy that can produce freckle defect；

Step 6, heating heat preserving formwork: after opening the circulation waterway of insulation power supply, power-on is powered；It is stepped up electricity Source voltage is until temperature is incubated after reaching to state the alloy melting temperature that can produce freckle defect；

Step 7, installs traveling-wave magnetic field generator and applies magnetic field: travelling-magnetic-field coil is fixed on conventional directional solidification and sets Standby load coil is peripheral, and makes the center of circle of load coil and travelling-magnetic-field coil ensure to overlap；

Step 8, casting and pull: the alloy melt that the meeting of fusing produces in step 6 freckle defect is poured in formwork； Set withdrawing rate as 20～80 μm/s, by pumping rod, formwork is sent into cold-zone by hot-zone subsequently, complete lead The pull of ashbury metal；Stop pull；Stop insulation power supply and travelling-magnetic-field power supply；Stop after being incubated at least 15min Gear oil pump, stops water pump cooling after graphite cannula temperature is less than 150 DEG C, obtains the alloy without producing freckle defect Foundry goods.

2. externally-applied magnetic field controls the directional freeze method of freckle defect as claimed in claim 1, it is characterised in that described checking The process in the magnetic field in numerical simulation is, arranges the numerical value of electric current of travelling-magnetic-field device in experiment, the number of frequency The numerical value at value and phase angle and the numerical value of electric current, the numerical value of frequency and the phase angle in Ansys emag numerical simulation Difference numerical value identical, and utilize routine magnetic field measuring instrument-Tesla meter space magnetic field is measured；Will The measurement result obtained contrasts with analog result；If error is more than 5%, then comes back to the 4th step and adjust Calculate parameter until error carries out the 7th step after being less than 5%；If error is less than 5%, carry out the 7th step；Described tune Whole calculating parameter is to reduce the value of relaxation factor in Ansys emag computed in software magnetic field process with the step-length of 0.1, The value input Ansys emag software of the relaxation factor after reducing, the utilization repeating the 5th step and the 6th step is conventional Magnetic field measuring instrument-Tesla meter space magnetic field is measured, and by the measurement result obtained and analog result Contrast；If to ratio error less than 5%, carrying out the 7th step；If to ratio error more than 5%, continuing with 0.1 Step-length adjust coefficient of dispersion value；The value input Ansys emag software of the coefficient of dispersion after reducing, repeats Space magnetic field is measured by the conventional magnetic field measuring instrument-Tesla meter that utilizes of the 5th step and the 6th step, and will The measurement result obtained contrasts with analog result；If to ratio error less than 5%, carrying out the 7th step；If contrast Error is more than 5% process repeating described Adjustable calculation parameter, adjusts the value of relaxation factor and discrete the most respectively The value of coefficient is until the error of described measurement result and analog result is less than 5%.

3. externally-applied magnetic field controls the directional freeze method of freckle defect as claimed in claim 1, it is characterised in that when described conjunction When gold is terne metal, current settings is 10～22A, frequency setting is 20～50Hz, and magnetic field intensity is 10mT； When described alloy is nickel base superalloy, current settings is 22～27A, frequency is 50Hz, and magnetic field intensity is 24～28.5mT.

4. as claimed in claim 1 externally-applied magnetic field controls the directional freeze method of freckle defect, it is characterised in that described can produce The thermal physical property parameter of alloy and the thermal physical property parameter of formwork of raw freckle defect each mean that this foundry goods is in process of setting Thermal conductivity, viscosity, density, latent heat of solidification, thermal coefficient of expansion and formwork thermal conductivity at different temperatures.

5. as claimed in claim 1 externally-applied magnetic field controls the directional freeze method of freckle defect, it is characterised in that described can produce The withdrawing rate of alloy-steel casting and the initial condition of directional solidification process of raw freckle defect refer to produce this described The heating-up temperature of the alloy-steel casting of raw freckle defect and withdrawing rate；Described heating-up temperature is and described can produce passeris montani saturati The fusion temperature of the alloy of speckle defect；Described withdrawing rate is 20～80 μm/s.

6. externally-applied magnetic field controls the directional freeze method of freckle defect as claimed in claim 1, it is characterised in that described heating During melted alloy, when described alloy is terne metal, lead raw material and stannum raw material press lead: stannum=67:33's Mass fraction ratio.