CN1296502C - Magnesium alloy sectional stocks, their continuous casting method and device - Google Patents
Magnesium alloy sectional stocks, their continuous casting method and device Download PDFInfo
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- CN1296502C CN1296502C CNB021561710A CN02156171A CN1296502C CN 1296502 C CN1296502 C CN 1296502C CN B021561710 A CNB021561710 A CN B021561710A CN 02156171 A CN02156171 A CN 02156171A CN 1296502 C CN1296502 C CN 1296502C
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/14—Plants for continuous casting
- B22D11/143—Plants for continuous casting for horizontal casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
Abstract
The invention relates to a magnesium alloy cast, as well as a continuously-casting method and apparatus. The magnesium alloy material is melted under state of shutting off from oxygen and the magnesium alloy cast (1), with little casting defect and areas (3) in which mean concentration of at least one composition except magnesium is higher than the ratio of the alloy composition, dispersed in the magnesium alloy crystal grain exists, is obtained by cooling and solidifying the molten-state magnesium alloy.
Description
Technical field
The present invention relates to make magnesium alloy profiles blank, its continuous casing and the continuous casting apparatus that plastic working is used that be cast as that magnesium alloy parts uses with magnesium alloy materials.
Background technology
In recent years, as for mass-produced household electrical appliance, one of countermeasure of recycling processing and environmental problem etc., outer dress member that replaces resin material fabricator electrical appliance in the past with metallic substance etc. is noticeable.The recirculation rate of resin material is 20% relatively, and metallic substance 90% recirculation is possible.
In the metallic substance, especially magnesium alloy is compared with other metal alloys, light weight, intensity height, and vibration damping is also excellent.Practicability in portable electric appts, auto parts etc. just.And the magnesium alloy fusing point is lower, and therefore the characteristics of recirculation less energy consumption are arranged.
Fig. 8 is an operation synoptic diagram of making magnesium alloy parts with magnesium alloy materials.At first, in order to obtain Mg alloy formed article with magnesium alloy materials, the casting that is called pressure die casting, investment cast of general rough classification, press working, bending machining, forged plastic working.The reverse side that the degree of freedom of cast form is high exists casting surface defect, bubble to be involved in inner problem, therefore has yield rate low, the problem that cost is high.So, about shell of the fairly simple household electrical appliance of shape etc., in advance behind the section bar blank of the net shape of the approximate part of casting, to the direct plastic working of this section bar blank, or implement extruding, calendering etc. and be processed into thin plate 1 time, thin plate is implemented secondary processing, form Mg alloy formed article, make the method for magnesium alloy parts also just in practicability through the coating, drying operation afterwards.The method that casting and plastic working are made up is compared with the method for independent casting, thinks and sees it is favourable from the shortened channelization, minimizing surface imperfection, the operating device investment aspect that add man-hour.
Fig. 7 is the state graph of the general plastic working of this manufacture method use of analog representation with the metallographic structure of section bar blank.Section bar blank 4 is except magnesium, is the magnesium alloy of the AZ31 of main alloy element with aluminium, zinc, manganese.AZ series magnesium alloy is compared with other magnesium alloy, the intensity height, and solidity to corrosion is excellent, is the alloy of shell that is suitable for easily being exposed to the household electrical appliance of sweat, water.
The crystalline structure of magnesium alloy is a hexagonal, and the crystal boundary slip plane is few, and with other metallographic phase ratios, plastic working is poor.Therefore,, propose utilization and control the speed of cooling of magnesium alloy, add grain-refining agent, implement the motion of crystal grain diameter refinement in the past for improving plastic working., clear and definite crystal grain diameter refinement is adding the machining deformation amount in man-hour 1 time by extruding, calendering etc. and the operation of processing temperature can be controlled to a certain degree.
In the section bar blank stage, the occasion that the segregation of casting flaw, inclusion is many, it is never easy to improve those defectives during time processing.Be that magnesium alloy profiles blank shown in Figure 10 is exactly such.Section bar blank 4, compound zone 6 be in grain boundary segregation, the existence of magnesium alloy crystalline phase 5, and the internal voids that takes place during casting 7 is separated out at crystal boundary.
Generally, during fused AZ series magnesium alloy solidification, along with the nucleus of magnesium is grown up, the composition (metal or oxide compound) that is difficult to solid solution in the magnesium is often separated out with states such as intermetallicss near crystal boundary in crystal boundary segregation gradually.And the gaseous constituent of difficult solid solution in the magnesium is collected at the crystal boundary of magnesium when solidifying, and forms space 7 and stays section bar blank 4 inside.
The position of casting flaw or inclusion segregation is becoming thin plate with 4 plastic workings of section bar blank, when the thin plate plastic working is molding, becomes the crack initiation point easily then, and such section bar blank 4 lacks processibilities.Especially, slip system is few, shortage ductile magnesium alloy, and the degree of the quality left and right sides processibility of material is big, and for the processibility that makes such magnesium alloy improves, preferably reducing becomes the casting flaw and the inclusion of the raw-material section bar blank of thin plate, and prevents segregation.
Therefore, in view of aforementioned practical problems, the objective of the invention is, provide and utilize casting flaw, the inclusion that reduces metallographic structure and prevent segregation, when the time processing that can improve extruding, calendering etc. becomes thin plate, or 2 times of being processed into that thin plate forges etc. are again added the magnesium alloy profiles blank of the plastic working in man-hour.
Summary of the invention
For the magnesium alloy profiles blank of the present invention that reaches aforementioned purpose exploitation is a casting plastic working magnesium alloy profiles blank, the feature of this section bar blank is, the high zone of ratio of the relative alloy composition of mean concns of composition beyond the magnesium, dispersion is present in the inside of the crystal grain of magnesium alloy.
Composition outside the so-called aforementioned magnesium is meant aluminium, zinc, the manganese as alloy main composition element.Inclusiones such as the oxide compound, carbide of metal beyond these main composition elements and these metals are also contained in alloy inside.The difficult solid solution of most inclusiones is in the zone of Mg, and is subsidiary or be contained in aforementioned " the high zone of ratio of the relative alloy composition of mean concns of composition beyond the magnesium ".
Below, should " the high zone of ratio of the relative alloy composition of mean concns of the composition beyond the magnesium " also comprise the situation that contains inclusion, mainly be called " compound zone ".So-called compound zone is that the dendrite that is magnesium alloy ghost peakization takes place mutually, generates the state of crystal boundary in intragranular dispersion state, and the composition that presents the compound zone is inserted in the state in the framework of dendrite phase with residual dispersion.
Like this, because the compound zone is dispersed in intragranular, inclusion also becomes and disperses to exist, and becomes the reduced in segregation of big inclusion of the cracking point class of crackle, and the section bar blank itself is rich in ductility.The section bar blank is rich in ductility, and then the thin plate to 1 processing such as section bar blank enforcement extruding, calenderings also is rich in ductility, and it is good that plastic working becomes.
The proportion of composing of the alloying constituent that practical magnesium alloy should contain according to the ASTM standard code.Aforementioned so-called compound zone, it is the high zone of the relative alloy composition of mean concns of the composition beyond the magnesium, say closely and can stipulate that in the alloying constituent beyond the magnesium of ASTM standard code, its concentration is above the zone of the standard max value of this composition of ASTM standard code.
In the present invention, this compound zone is decided to be zone more than the mean diameter 5 μ m.Which kind of magnesium alloy no matter, if observe inner compound and the metal that exists from atomic level, certainly exist " the high zone of the relative alloy composition of mean concns of the composition beyond the magnesium ", and feature of the present invention is, do not have aforesaid atomic level compound zone, be dispersed with the zone of a certain size (more than the 5 μ m).
Mensuration such as in addition, the constituent concentration in compound zone can enough SEM-EDS (scanning electron microscope can loose X linear light spectrometer).
The whole proportion of aforementioned alloy profile blank (occasion that is called for short the section bar blank is also arranged) is according to 98～100% of the theoretical density of alloying element composition calculating.Promptly the metallographic structure of section bar blank is interior to be lacked because space and gas are involved in, and is rich in ductility.Therefore, when section bar blank extruding or calendering etc. are processed to form thin plate for 1 time, and, when 2 processing such as this thin plate enforcement forging, can prevent that its space (space and cavity) part from rupturing adding the cracking point that becomes crackle man-hour, even in the time of can preventing the molding coating, drying after the processing, breaking of air entrapment produces the problem of surface imperfection.
Section bar blank of the present invention is beyond the demagging, contains the AZ series magnesium alloy of aluminium as main component, zinc, manganese, wherein contains aluminium 2～10wt%.According to aforementioned, AZ series magnesium alloy intensity, corrosion excellence are as the extensive practicability of structured material.
Feature of the present invention is, the compound zone is dispersed in intragranular, but aluminum content does not reach 2%, then account in intragranular compound zone and tail off, so the compound zone disperses, inclusion dispersive effect just goes down, thereby, think the plastic working deterioration of section bar blank.On the contrary, aluminum content is higher than 10% section bar blank, because the volume in compound zone own becomes big, becomes the situation that the bigger inclusion of volume ratio can exist in the compound zone, thinks the possibility that has the plastic working deterioration.Yet section bar blank of the present invention is the magnesium alloy profiles blank that contains aluminium 2～10wt%, and expectability becomes the excellent section bar blank of plastic working in the intragranular dispersive effect that is mingled with.
The cylindrical blank of common cast material, process extrusion process or forging and pressing operation are processed to tabular, make through calendering afterwards to supply in the magnesium alloy case sheet material of plastic working.On the one hand, the shape of aforementioned section bar blank of the present invention is formed tabular, then, regulate thickness of slab and just can obtain supplying, thereby can simplify working process, seek to reduce cost in the magnesium alloy case sheet material of plastic working without extrusion process or the only calendering for several times of forging and pressing operation.
If below the thickness of slab 10mm of aforementioned section bar blank, then without extrusion process or forging and pressing operation, only calendering for several times just obtains the thin plate about the thickness of slab 0.3～1.5mm of shell the best of household electrical appliance, thereby can simplify working process more, seeks cost and reduces.
In the X ray diffracting spectrum of aforementioned section bar blank, crystalline (0002) face on surface preferentially occurs, thereby clear and definite, be characterised in that material surface solidify when crystal growth direction.In general, magnesium alloy bears in stressed, and (0002) face becomes significantly, and the present invention's product are under pressure when showing casting.
In order to reach aforementioned purpose, the feature of the continuous casing of magnesium alloy profiles blank of the present invention is to comprise following 2 operations, promptly, magnesium alloy materials is dropped in the crucible, magnesium alloy materials under the oxygen barrier state in the fusion crucible, after supplying with the cooled mold, make the magnesium alloy cooling of molten state, the operation of solidifying, and the operation of this magnesium alloy that solidifies of drawing from the cooled mold intermittently or continuously.
When the magnesium alloy of molten state solidifies in the cooled mold, because the magnesium alloy part that intermittence or continuous drawing solidify, formation will be present in the gaseous constituent of the solid-liquid interface of solidifying and be mingled with to liquid portion with mass force and vibration extrudes, and can reduce being included in section bar blank gas inside composition and inclusion.
The speed of cooling of the cooled mold in this continuous casing is 3～8K/ second.The speed of cooling of this 3～8K/ second is, on one side the dendrite that utilizes the cooling magnesium alloy grow, solidified mutually, utilizes the interior thermal conduction of section bar blank to carry out spot anneling again, and dendrite carries out the speed of cooling that ghost peakization is the best mutually.As previously mentioned, the compound zone is stayed in the framework of dendrite phase of ghost peakization, and there is intragranular in the compound zone with the dispersive state, and then inclusion disperses to exist, and can access the superior section bar blank of plastic working.
This continuous casing, magnesium alloy materials is to melt under the state of occluded oxygen, prevents to contact oxygen and burns, and in order to cut off oxygen, employing places crucible under the atmosphere of inert gases gas or with degasifier and drops into the magnesium alloy of molten state, so that oxygen does not contact the method for liquid level.Use argon gas, helium and be mixed with the air etc. of SF6 as rare gas element.As degasifier, can use Repone K, magnesium chloride anti-flaming degasifier as main body.With the occasion that degasifier drops into material, the effect that prevents the evaporation of metal that takes place from the Mg alloy surface of molten state is arranged also.
In the preceding method, make solids if drop into the magnesium alloy materials of crucible, remain at crucible periphery atmosphere gas under the state of inert atmosphere gas and feed intake, even the crucible of fusing magnesium alloy does not possess the material stock stove, then the granular solids material feeds intake continuously or intermittently, can not interrupt feeding intake and cast continuously.Especially, because occluded oxygen, when the Mg alloy surface in crucible produces protection atmosphere gas; discharge inert atmosphere gas for feeding intake, then will consume productive temp for setting up inert atmosphere gas once more, and if adopt present method; can not feed intake even do not discharge inert atmosphere gas yet, therefore can shorten productive temp.
In order to reach aforementioned purpose, the continuous casting apparatus of magnesium alloy profiles blank of the present invention possesses the crucible that loads magnesium alloy materials and make its fusing by heating unit; Link to each other with crucible and the magnesium alloy by refrigerating unit cooling molten state makes it be frozen into the cooled mold of desired shape; The draw-off gear of intermittence or the magnesium alloy that drawing is solidified from the cooled mold continuously.
In the aforementioned means, the inwall section of cooled mold is a rectangle, at least a portion in the aforementioned inwall forms taper so that the crucible side is different with the length of the mold minor face of draw-off gear side, be added on the stress increase and decrease of magnesium alloy in the time of drawing can being made like this, thereby carry out the upgrading of material behavior, and seek to make the friction of ingot bar and mold to tail off, prevent the ingot bar hot tearing.
In aforementioned means, material as crucible and/or cooled mold is selected graphite, then thermal conductivity is excellent, can the smooth implementation material heating cool off, be suitable, and that other are difficult to the material that reacts with magnesium alloy is also passable, preferably, do not contain and sneak into the section bar blank, then obviously influence the material of corrosion proof copper, nickel, iron.In addition, also there is report graphite to sneak into magnesium alloy, then the fact of grain refining.
In aforementioned means, for example at the arranged outside container of crucible, can control the structure of the atmosphere gas of putting crucible, so that, for example vacuumize maybe and can replace rare gas element the structure that the periphery of the surface of fused magnesium alloy in the crucible or crucible can occluded oxygen.And because of being the magnesium alloy of molten state, frequent generating gasification in order to manage that metallic vapor is not put in the atmosphere, preferably is provided with container.
In the aforementioned means, as possesses the lid that to uncap to crucible, then can suppress metallic vapor and be diffused into the crucible outside, the powdery metal that the metallic vapor that reduces diffusion solidifies attached to aforementioned container inner wall etc., preventing because of powdery metal savings material qualification rate is low, and the danger of spontaneous combustion.In addition, method is described like that as described above, as the device that the magnesium alloy materials in the crucible is cut off oxygen, degasifier is mixed in the material, also may control evaporation from the Mg alloy surface of molten state, but this occasion exists the degasifier composition to sneak into the danger of section bar blank, thereby preferably with what is called crucible dress lid is improved the device correspondence.
Aforementioned means is that the cooled mold links to each other with the crucible side, the horizontal type continuous casting apparatus of along continuous straight runs drawing magnesium alloy.Can prevent to float over the impurity of the magnesium alloy liquid level of molten state like this, and the impurity of savings at the bottom of crucible is involved in, can makes and be rich in ductility, highly organized magnesium alloy profiles blank.
Description of drawings
Fig. 1 is the sectional view of metallographic structure of the AZ series magnesium alloy section bar blank of analog representation embodiments of the present invention.
Fig. 2 is the cross-section photograph of sweeping anchor electron microscope (SEM) shooting of the AZ series magnesium alloy section bar blank of this embodiment.
Fig. 3 A～Fig. 3 C is the cross-section photograph that the opticmicroscope of the AZ series magnesium alloy section bar blank of this embodiment is taken.
Fig. 4 is the graphic representation that lists the X-ray diffractogram of the condition of surface of this magnesium alloy profiles blank in this embodiment.
Fig. 5 is the longitudinal section that the continuous casting apparatus of this embodiment represented in summary.
Fig. 6 is in this embodiment, so that the longitudinal section of wanting portion of the continuous casting apparatus of the taper that the withdrawing roll side broadens.
Fig. 7 is in this embodiment, so that the longitudinal section of wanting portion of the continuous casting apparatus of the taper of withdrawing roll side stenosis.
Fig. 8 is a general synoptic diagram of making the magnesium alloy parts operation with magnesium alloy materials.
Fig. 9 is the synoptic diagram of square container drawing and forming evaluation with the magnesium alloy sheet blank.
The sectional view of the metallographic structure of Figure 10 AZ series magnesium alloy section bar blank that to be analog representation make of in the past castmethod and casting device.
Embodiment
Below, with reference to Fig. 1～Fig. 9 embodiments of the present invention are described.Embodiment shown below is 1 example that the present invention is specialized, and limits technical scope of the present invention anything but.
Fig. 1 is the sectional view of state of metallographic structure of the magnesium alloy profiles blank 1 of analog representation present embodiment.This magnesium alloy profiles blank 1 is to adopt castmethod described later, the magnesium alloy AZ31 of aluminium content about 3%, zinc content about 1% is configured as tabular, (crystal grain inside and outside) disperses, exists compound zone (the high zone of ratio of the relative alloy composition of mean concns of the composition beyond the magnesium) 3 in the inside of magnesium alloy crystalline phase 2.
This state is the composition by the compound zone 3 of the structure disjunction of the dendrite phase of magnesium, even and dendrite phase ghost peak dissolves the state of existing crystal boundary, also think to keep being dispersed in intragranular state.
Following table 1 lists the component proportions of the magnesium alloy profiles blank 1 of the ASTM standard of AZ31 magnesium alloy and present embodiment.Unit is weight %.In addition, utilize the ICP emission spectroanalysis to carry out composition measurement in the present embodiment.
The ASTM standard of table 1 AZ31 magnesium alloy reaches
The component proportions of present embodiment (weight %)
| Al | Zn | Mn | Fe | Si | Cu | Ni | Ca | |
| The ASTM standard | 2.5～ 3.5 | 0.5～ 1.5 | ≥ 0.20 | ≤0.03 | ≤ 0.10 | ≤0.1 | ≤ 0.005 | ＜0.04 |
| The present embodiment goods | 3.0 | 0.99 | 0.22 | 0.0047 | 0.022 | 0.0017 | 0.0012 | 0.0001 |
*The surplus Mg that is divided into
Fig. 2 is the cross-section photograph of metallographic structure of the magnesium alloy profiles blank 1 of scanning electron microscope (SEM) present embodiment of taking.Shown in the figure 31～34th, the measuring point that the scanning electron microscope-X linear light spectrometer (SEM-EDS) that can loose is measured, following table 2 lists the element composition (weight %) of each measuring point.
The element constituent ratio (weight %) of the measuring point of table 2 Fig. 2
| Measuring point 31 | Measuring point 32 | Measuring point 33 | Measuring point 34 | ||||
| Element | Weight % | Element | Weight % | Element | Weight % | Element | Weight % |
| Mg | 100.00 | C | 17.76 | Mg | 55.96 | Mg | 92.78 |
| O | 13.39 | Al | 21.16 | Al | 4.63 | ||
| Mg | 35.91 | Zn | 22.88 | Zn | 2.59 | ||
| Al | 15.40 | ||||||
| Mn | 17.12 | ||||||
| Zn | 0.41 | ||||||
As the component ratio of the section bar blank integral body of present embodiment, according to shown in the table 1, all in the ASTM standard.; the compound zone of present embodiment is that the high zone of ratio of the relative alloy composition of mean concns of composition beyond the magnesium is the point shown in the measuring point 32～34 of Fig. 2; and it is as shown in table 2; in the element beyond the Mg of so-called Al, Zn, the ratio of the element more than at least a kind is bigger than the higher limit of ASTM standard.
In addition, measuring point 2 is, the ratio of unspecified C of ASTM standard and O uprises, and this represents to comprise in this compound zone the possibility of carbide and oxide compound.
Above-mentioned precipitate zone corresponding to the distribution of crystal grain shown in Fig. 3 A, B and C.Fig. 3 A is the part opticmicroscope cross-section photograph of tabular magnesium alloy profiles blank 1a of the thick 10mm of aforementioned embodiments.Can be observed crystal boundary 8, the mean diameter of crystal grain is about 200 μ m, and the inside of crystal grain disperses to have compound zone 3, is converted into the circular diameter corresponding with the crystal grain internal area for counting about μ m～30 μ m.In the section structure, the size in this precipitate zone 3 reaches mostly and is equivalent to the above degree of circular diameter 5 μ m.In the cross-section photograph of Fig. 3 A, observe the precipitate zone that is equivalent to more than the circular diameter 5 μ m 3 about 30～40 1 crystal grain inside.
The part opticmicroscope cross-section photograph of the tabular magnesium alloy profiles blank 1b of the thick 5mm of Fig. 3 B.Observe crystal boundary 8, the mean diameter of crystal grain is about 80 μ m.In this section structure, observe the precipitate zone that is equivalent to more than the circular diameter 5 μ m 3 about 3～20 1 crystal grain inside.
Fig. 3 C is the part opticmicroscope cross-section photograph of the tabular magnesium alloy profiles blank 1c of thick 3mm.Observe crystal boundary 8, the about 250 μ m of average grain diameter.In this section structure, observe 1 crystal grain inside and to be equivalent to circular diameter and to reach precipitate zone 3 about 60～120 more than the 5 μ m.
Like this, the magnesium alloy profiles blank 1 of present embodiment general section bar blank 4 in the past as shown in figure 10 is such, crystal boundary in magnesium alloy crystalline phase 5 does not have segregation, exists the compound zone, does not separate out at crystal boundary in the space 7 that takes place during casting yet, because compound zone 3 is smaller sizes, and the dispersive state, being mingled with service also disperses to exist, push for magnesium alloy profiles blank 1 is processed into thin plate, be difficult to during calendering rupture, be rich in ductility.And even be processed into the occasion of thin plate, this thin plate is rich in ductility, becomes the occasion of implementing 2 processing such as punch process, forging, the material of excellent processability.
Table 3 is the results that measure the proportion of the sample that cuts at random from the magnesium alloy profiles blank 1 of present embodiment.In addition, the volume of this sample to profile mechanical workout after size up calculate.
The proportion of the magnesium alloy profiles blank of table 3 present embodiment
| Specimen coding |
| 1 | 2 | 3 | |
| Volume (cm 3) | 1.241 | 4.526 | 8.355 |
| Weight (g) | 2.177 | 7.977 | 14.78 |
| Density (g/cm 3) | 1.754 | 1.763 | 1.769 |
| Corresponding to theoretical density (1.78g/cm 3) ratio | 98.6％ | 99.0％ | 99.4％ |
Even beyond the aforementioned sample, the ratio of the magnesium alloy profiles blank 1 of present embodiment weighs in 98～100% the scope of the theoretical density that calculates according to this alloy composition.On the one hand, in shown in Figure 7 and the section bar blank 4 magnesium alloy profiles blank 1 same composition, because there are many spaces 7 in inside, proportion is less than aforementioned theoretical density 1.78g/cm
398% (proportion 1.744g/cm
3Below) partly many.Organizing of the magnesium alloy profiles blank 1 of present embodiment is close, and internal voids is few, consequently, the extruding of back operation or calendering, and in 2 processing afterwards, be difficult to fracture, even and in the coating, drying operation (Fig. 8), also can avoid air entrapment and break and cause the problem of surface imperfection.
In the present embodiment, with castmethod shaping magnesium alloy profiles blank 1 described later, so that form thickness of slab 3mm, 5mm, 10mm.Do not find that the feature of aforesaid section structure and proportion have significant difference owing to this thickness of slab difference of 3 kinds.
Present embodiment is used the AZ31 magnesium alloy, also can use other AZ series magnesium alloy.But,, preferably contain the magnesium alloy of the AZ series of Al 2～10Wt% for realizing having the section structure of aforementioned feature.
The X-ray diffraction analysis was once carried out on the surface of the section bar blank 1 of present embodiment, and as shown in Figure 4, the crystal orientation of (0002) face becomes the figure of preferential demonstration.This phenomenon thinks, during material solidification from material surface vertical direction pressure in addition.
Fig. 5 is the pie graph of continuous casting apparatus 21 of making magnesium alloy profiles blank 1 usefulness of present embodiment.
Continuous casting apparatus 21 is by accommodating magnesium alloy materials 13, and with the crucible 11 of electric heater (heating unit) 12 fusings; Continue with crucible 11, and with the magnesium alloy 13a of water cooling tube (refrigerating unit) 20 cooling molten states, make it to be frozen into the cooled mold 15 of the shape of requirement; Be dummy bar 16 and withdrawing roll 17 formations from cooled mold 15 interior draw-off gears intermittently or the magnesium alloy 13b that the successive drawing is solidified.
In this continuous casting apparatus 21, the magnesium alloy materials 13 that drops into crucible 11 becomes the magnesium alloy 13a of molten state by electric heater 12 heating.Because magnesium alloy is at the just acutely burning of molten state-touch oxygen, best occluded oxygen during fusion.As the device of occluded oxygen, be that crucible 11 is arranged in the container 14 in the present embodiment, become the not shown structure that can vacuumize and drop into rare gas element.
The magnesium alloy 13a of molten accumulates in the crucible 11, but also flows in the cooled mold 15 that directly links crucible 11, and therefore, formation makes dummy bar 16 can enough pass in and out the structure of cooled mold 15 inside from the lower side of container 14 with withdrawing roll 17.In addition, the continuous casting operation forms the magnesium alloy 13b that the solidifies replacement dummy bar 16 of previous drawing midway, suppresses the effusive formation of the magnesium alloy 13a of molten state.
Cooled mold 15 absorbs the heat that molten magnesium alloy 13a emits, and is discharged into periphery, and present embodiment forms the formation of the heat that absorbs aforementioned release at circumferential arrangement water cooling tube 20 refrigerating units such as grade of cooled mold 15.Absorb and become the formation that to regulate discharge and temperature when hot.As such refrigerating unit, except that water-cooled, also can adopt the formation of air cooling.
The cross-sectional shape of cooled mold 15 inwalls, become the magnesium alloy 13b that solidifies in the wall within it, the cross-sectional shape of magnesium alloy profiles blank 1 just, the inner wall section shape of regulation cooled mold 15 in the present embodiment is so that the cross-sectional shape of magnesium alloy profiles blank 1 becomes the rectangle of wide 50mm * thick 3mm or 5mm or 10mm.And the cooling segment length of cooled mold 15 is 170mm, and the shape of the magnesium alloy profiles blanks of casting in the consideration cooled mold 15 and cooling water inflow etc. also can be set other length.
When using aforementioned such continuous casting apparatus that constitutes to cast magnesium alloy profiles blank 1 continuously, the occasion that the magnesium alloy 13b (ingot bar) that solidifies easily ruptures midway, as shown in Figure 6, make tapered 15a at the inwall of cooled mold 15, so that the relative crucible 11 of withdrawing roll 17 sides broadens gradually, the friction of minimizing and cooled mold 15 can make ingot bar be difficult to fracture midway.And it is opposite, as shown in Figure 7, at the sequential portion formation taper 15b of cooled mold 15 with crucible 11, so that the relative crucible 11 side stenosis of withdrawing roll 17 sides, then to the part of solidifying of the magnesium alloy 13a of molten state, from the relative drawing direction vertical direction stress of appropriateness in addition, then can reduce the inclusion and the gas volume that are involved in the section bar blank.
The crucible 11 that fusing magnesium alloy materials 13 is housed becomes inner dark 220mm, vertical direction at the about 10mm in distance bottom surface connects cooled mold 15, when pulling to the magnesium alloy 13a of molten state in the cooled mold 15, the impurity 19 of savings in crucible 11 bottom surfaces is difficult to be involved in the formation of magnesium alloy 13b.
The chute that feeds intake (material feeding apparatus) 18 shown in Figure 5 is arranged on the top of container 14, so that needn't open and close container 14 magnesium alloy materials 13 is dropped in the crucible 11 continuously.In addition, if the size that the shape crucible 11 of the magnesium alloy materials 13 that the initial stage drops into holds is then no problem, but when feeding intake by the chute 18 that feeds intake, preferably particle shape about diameter 1mm～10mm or smear metal shape prevent that the magnesium alloy 13a of crucible 11 breakages and molten state is splashed to outside the crucible 11.
The continuous casting apparatus 21 of present embodiment is that cooled mold 15 is connected in crucible 11 lateral horizontal types, also can use cooled mold 15 to be connected in the vertical device of crucible 11 bottom surfaces.
Be to use the radio-frequency heater that can realize 10KW left and right sides power as the electric heater 12 of heating unit, and if have that alloy material is heated to the heating unit of the capacity more than 780 ℃ is also passable, be not limited to radio-frequency heater.
The crucible 11 of present embodiment and cooled mold 15 usefulness graphite are made, and graphite is excellent thermal conductivity, and the material that is difficult to react with the magnesium alloy 13a of molten state.And, do not wish to contain the material that the material that influences the tangible copper of material solidity to corrosion, nickel, iron when sneaking into magnesium alloy is used as crucible 11 and cooled mold 15.
The magnesium alloy 13a of molten state evaporates when flat, the solidify out into powder such as inwall of metal vapors one contacting container 14.This phenomenon not only reduces the material qualification rate, and may spontaneous combustion, is dangerous, preferably possess can switch to crucible lid (not shown).And uncap when preferably only feeding intake, prevent that metal vapors from flowing to the outer formation of crucible 11.
High temperature (about 650～800 ℃) when dummy bar 16 preferably melts with anti-magnesium alloy materials, and keep the material of intensity to make, and present embodiment is used stainless steel making spindle blade.
Then, specify continuous casing with the magnesium alloy profiles blank of aforementioned such continuous casting apparatus that constitutes 21.
At first magnesium alloy materials 13 is dropped in the crucible 11, container 14 cuts out the formation air-tight state.
After then container 14 inside being vacuumized, injecting inert gas, preferably argon gas makes inside be full of rare gas element.At this moment, the pressure in the container 14 is 0.1～0.2 torr when for example vacuumizing, and can reach 14～18 torrs during injecting inert gas, but also be not limited to this.Gas purging mouth in the container when injecting as the noble gas body is set at container 14 so that during injecting inert gas, will enter inner gas cloud the initial stage and discharge from discharge outlet, also can form and omit the operation that vacuumizes.
Then make water flow cooled mold 15 and dummy bar 16 at the water cooling tube 20 of the refrigerating unit that is disposed at cooled mold 15 peripheries.At this moment the water yield is controlled at 0.5～2.0 liter/minute, and water temperature is controlled at 20～35 ℃, but also is not limited to this condition.
Then, with electric heater 12 heating crucibles 11, make magnesium alloy materials 13 fusings.The AZ31 magnesium alloy is heated to fusing point just fusing more than 630 ℃.And the present embodiment is considered the thermograde of molten metal flow and metal inside, and decision remains on 750～780 ℃.Be low because of molten metal temperature, ingot bar (the magnesium alloy 13b that the solidifies) experimental result of easily being interrupted then.This phenomenon thinks that molten metal temperature is a low temperature, then takes place inhomogeneously in the process that is cooled of metal, and the cause that solid-liquid interfaces hinder continuous solidifications takes place at a plurality of positions during continuous casting.
Molten metal is controlled at aforesaid temperature, then mobile increasing, surface tension reduces, and forms the state that inner contained gas is easily overflowed, and thinks that the result is that the space casting flaws such as (space, cavities) that remains in molding inside reduces.On the one hand, make temperature of melt metal when above, make energy dissipation up to necessary temp.And the vapour pressure of molten metal increases, and therefore, powdery metal is increased to the adhesion amount of crucible 11 and container 14, and this is undesirable.
Then, withdrawing roll 17 is rotated, dummy bar 16 in drawing.Present embodiment is controlled at 45～125mm/min with drawing speed at this moment.In addition, present embodiment is to carry out in the mode of drawing at intermittence, for example during drawing speed 100mm/min, speed drawing 5mm with 10mm/sec, at intermittence that this state stops 2.5sec under the drawing condition, cast continuously, it comprehensively reaches the drawing speed of 100mm/min.With the rotation of the Combination Control withdrawing roll 17 that just changes, reverses, then the limit repeatedly drawing and compress into, limit drawing magnesium alloy 13b also is possible.
With compare with the occasion of fixing speed continuous drawing magnesium alloy 13b, as the alternately stand-by time of present embodiment, the occasion mass force of intermittently drawing and the solid-liquid interface of solidifying that vibration imposes molten magnesium alloy 13, inclusion and bubble are discharged from liquid portion, thus can expect be configured as inclusion and space (space) less, the more excellent section bar blank of plastic working.
If abundant drawing dummy bar 16, the magnesium alloy 13b that solidifies reaches the position of withdrawing roll 17, and then the magnesium alloy 13b of this state bears the task of dummy bar 16.
Just the magnesium alloy 13b temperature that goes out from 15 drawings of cooled mold reaches about 100 ℃ or below it, uses the cooled mold 15 of cooling segment as 170mm in continuous casting apparatus 21.Thereby, during with 100mm/min speed drawing magnesium alloy 13b, in crucible be 780 ℃ magnesium alloy by 170mm during, (102 seconds) were cooled to 100 ℃ in promptly 1.7 minutes, therefore, can realize the about 6.7K/ speed of cooling of second.
Equally, during with the speed drawing magnesium alloy 13b of 45mm/min, reach the 3.0K/ speed of cooling of second, during with the speed drawing magnesium alloy 13b of 125mm/min, reach the 8.3K/ speed of cooling of second.In the present embodiment, confirm to be formed with the metallographic structure of feature as shown in Figure 1, it is the magnesium alloy profiles blank made from the continuous casting of aforementioned about 3～8K/ speed of cooling second, but consider the influence of the setting rate of metal for metallographic structure, then to obtain aforementioned metallographic structure with the speed of cooling of 1～20K/ roughly second be possible to prediction.When speed of cooling was too fast, residual dendritic crystalline phase became the tissue that the magnesium crystal boundary do not occur, and the occasion that speed of cooling is slow excessively is Gu dendritic crystalline phase completely dissolve becomes the tissue of compound zone 3 solid solution or mobile segregation in the crystalline phase 2 of pure magnesium.
Foregoing embodiment does not carry out solution treatment, thereby the section bar blank that can make, it is characterized in that, crystal boundary occurs, and the zone that the relative alloy composition ratio of composition beyond the magnesium is high disperses, is present in intragranular.
Adopt continuous casting, reduce with the magnesium alloy materials 13a in the crucible 11, the pressure that then imposes on the solid-liquid interface of material solidification reduces, and ingot bar (magnesium alloy 13b) becomes and easily is interrupted.Therefore, in the present embodiment, the material in the crucible 11 reduces to about half of initial stage charging capacity, then appends feed from the chute 18 that feeds intake.At this moment, the atmosphere gas in the container 14 needn't leak, and according to occasion, the limit is cast continuously, the limit feed also is possible.The method of this feed, a certain amount of material reduces the method for feeding at intermittence that feed is concentrated in the back, and progressively any in the continuous feeding method of feed when continuous cast materials reduces all be possible.
Then, introduce the superiority of plastic working of the magnesium alloy profiles blank 1 of present embodiment.
In the magnesium alloy profiles blank 1 of present embodiment, to shaping thickness of slab 3.0mm slab, the slab of the slab of shaping thickness of slab 5.0mm and shaping thickness of slab 10.0mm rolls respectively, obtains the thin plate of thickness of slab 0.5mm (being decided to be test board 1,2,3 successively) separately.Draft be about 10～30% cold rolling enforcement repeatedly so that crackle does not take place in slab, and between each calendering procedure, carry out 450 ℃ of annealing of 10 minutes.Through last cold rolling reach thickness of slab 0.5mm after, carry out about 200 ℃ of stress relievings of 1 hour.In addition, Shi Ji calendering number of times is that test board 1 is 6 times; Test board 2 is 7 times; Test board 3 is 12 times.
And having prepared is not the magnesium alloy sheet (test board 4) of thickness of slab 0.5mm of present embodiment, and it is that market is sold through extrusion processing and rolling processing and made.In addition, the average grain diameter of these 4 test boards is 7～12 μ m approximately.
These test boards are cut into 8 dihedral blank shapes (about 40mm * 40mm, 6mm is cut in the bight) shown in Figure 9, carry out drift shoulder R1.5mm, drift plane R2.0mm, and the square container drawing experiments of drift profile 25mm * 25mm, one-sided gap reaches 0.1mm.Control metal pattern lowering speed, the limit changes draw speed, test on the limit, and tight says, makes draw speed be changed to 100mm/s, 70mm/s, 50mm/s, 20mm/s, 5mm/s, 2mm/s, 1mm/s, 0.75mm/s, 0.5mm/s, 0.1mm/s experimentize.
The occasion that draw speed is fast, four jiaos of molding crackle occurs, and draw speed are shaped slowly, the molding of crackle then do not occurred, and top speed is decided to be ultimate elongation speed in the draw speed of crackle with not occurring, and tries to achieve the ultimate elongation speed of each test board.In addition, the temperature of metal pattern is set in 250 ℃, 200 ℃, 150 ℃, as lubricant, uses the sprays of molybdenumdisulphide system.A plurality of blanks 9 are prepared in test, and each condition is implemented more than 3 times, and the Visual Confirmation crackle occurs, again according to its mean state prescribed limit pull and stretch speed.
Following table 4 lists the Limit Drawing speed that aforementioned 4 tests are pulled out.
The Limit Drawing speed of each test board of table 4 (mm/sec of unit)
| The metal pattern temperature | The thin plate of making of the section bar blank of present embodiment | Commercially available thin | ||
| Test board | ||||
| 1 | Test board 2 | | Test board 4 | |
| 250 | 100 | 100 | 100 | 10 |
| 200℃ | 20 | 10 | 10 | 1 |
| 150 | 1 | 1 | 1 | 0.1 |
We can say that according to this experiment any 1 sheet material (test board 4) with the market sale is compared in the test board 1,2,3 that magnesium alloy profiles blank 1 calendering of present embodiment is made, even fast 10 times speed also is difficult to occur crackle, i.e. plastic working excellence.
Previous experiments result confirms the embodiment of plastic working superiority of the magnesium alloy profiles blank 1 of present embodiment, and stretch process not only, and to what is called forge, diastrophic other plastic workings also can expect same effect.
As above stated specification, if adopt the present invention, because of the casting flaw that can prevent the interior space of metallographic structure, cavity etc., the segregation of inclusion, thereby is rich in ductility, when section bar blank enforcement extruding, calendering etc. are processed to form thin plate 1 time, and, this thin plate is implemented forging etc. add man-hour 2 times, can prevent that its defect part from becoming adds crack initiation point and rupturing in man-hour, and, the section bar blank is rolled with regard to original state, be used for the occasion of plastic working with thin plate, also can simplify working process, seek cost and reduce.And, during to the molding coating, drying after the processing, can prevent that also breaking of air entrapment from causing the problem of surface imperfection.
Claims (2)
1. the Continuous casting process of magnesium alloy profiles blank, it is characterized in that, comprise following 2 operations, magnesium alloy materials is dropped in the crucible, after under the oxygen barrier state, making magnesium alloy materials fusing in the crucible supply with the cooled mold, make the magnesium alloy cooling of molten state, the operation of solidifying with the speed of cooling of 3～8K/ second; And the operation of the cakey magnesium alloy of drawing.
2. the continuous casing of magnesium alloy profiles blank as claimed in claim 1, its feature are that also the material that drops into melting appartus is a granular solids, keep under the inert state magnesium alloy of molten state being supplied with the cooled mold at peripheral atmosphere gas.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001382073 | 2001-12-14 | ||
| JP2001382073 | 2001-12-14 |
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| CN1424418A CN1424418A (en) | 2003-06-18 |
| CN1296502C true CN1296502C (en) | 2007-01-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021561710A Expired - Fee Related CN1296502C (en) | 2001-12-14 | 2002-12-13 | Magnesium alloy sectional stocks, their continuous casting method and device |
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| Country | Link |
|---|---|
| US (1) | US20030159797A1 (en) |
| CN (1) | CN1296502C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101607360B (en) * | 2008-06-17 | 2011-01-05 | 北京达博有色金属焊料有限责任公司 | Mass production method for ultra-fine bonding gold wire |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1325197C (en) * | 2003-08-07 | 2007-07-11 | 李华伦 | Double roll super high speed continuous casting machine for thin magnesium strip |
| CA2723075C (en) * | 2004-06-30 | 2015-10-06 | Sumitomo Electric Industries, Ltd. | Magnesium alloy cast material |
| JP2006124795A (en) * | 2004-10-29 | 2006-05-18 | National Institute Of Advanced Industrial & Technology | Housing made from magnesium alloy |
| KR100591619B1 (en) * | 2004-11-04 | 2006-06-20 | 한국기계연구원 | An apparatus for horizontal continuous casting of magnesium alloys plate and manufacturing method thereof |
| KR20070107757A (en) * | 2005-03-02 | 2007-11-07 | 니혼쥬카가쿠고교가부시키가이샤 | Method of melting alloy containing high-vapor-pressure metal |
| KR101082946B1 (en) | 2009-08-07 | 2011-11-11 | 주식회사 엠.이.시 | Method for producing an ingot using an electric furnace |
| CN105855524A (en) * | 2016-05-27 | 2016-08-17 | 安徽鑫佳铜业有限公司 | Cast copper cooling waste heat reutilization device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4515204A (en) * | 1982-12-15 | 1985-05-07 | Nippon Light Metal Company Limited | Continuous metal casting |
| US5139077A (en) * | 1988-03-07 | 1992-08-18 | Allied-Signal Inc. | Ingot cast magnesium alloys with improved corrosion resistance |
| US5551996A (en) * | 1993-03-30 | 1996-09-03 | Ube Industries, Ltd. | Si-containing magnesium alloy for casting with melt thereof |
| US5979534A (en) * | 1995-03-22 | 1999-11-09 | Hitachi Metals, Ltd. | Die casting method |
| CN1244821A (en) * | 1997-11-26 | 2000-02-16 | 石川岛播磨重工业株式会社 | Facility and method for manufacturing hot-rolled steel strip |
-
2002
- 2002-12-13 CN CNB021561710A patent/CN1296502C/en not_active Expired - Fee Related
- 2002-12-16 US US10/319,834 patent/US20030159797A1/en not_active Abandoned
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4515204A (en) * | 1982-12-15 | 1985-05-07 | Nippon Light Metal Company Limited | Continuous metal casting |
| US5139077A (en) * | 1988-03-07 | 1992-08-18 | Allied-Signal Inc. | Ingot cast magnesium alloys with improved corrosion resistance |
| US5551996A (en) * | 1993-03-30 | 1996-09-03 | Ube Industries, Ltd. | Si-containing magnesium alloy for casting with melt thereof |
| US5979534A (en) * | 1995-03-22 | 1999-11-09 | Hitachi Metals, Ltd. | Die casting method |
| CN1244821A (en) * | 1997-11-26 | 2000-02-16 | 石川岛播磨重工业株式会社 | Facility and method for manufacturing hot-rolled steel strip |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101607360B (en) * | 2008-06-17 | 2011-01-05 | 北京达博有色金属焊料有限责任公司 | Mass production method for ultra-fine bonding gold wire |
Also Published As
| Publication number | Publication date |
|---|---|
| US20030159797A1 (en) | 2003-08-28 |
| CN1424418A (en) | 2003-06-18 |
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