CN101918160B - Aggregate particles for molds - Google Patents

Aggregate particles for molds Download PDF

Info

Publication number
CN101918160B
CN101918160B CN200980103162.5A CN200980103162A CN101918160B CN 101918160 B CN101918160 B CN 101918160B CN 200980103162 A CN200980103162 A CN 200980103162A CN 101918160 B CN101918160 B CN 101918160B
Authority
CN
China
Prior art keywords
aggregate particles
molds
composition
particle
crystalline phase
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN200980103162.5A
Other languages
Chinese (zh)
Other versions
CN101918160A (en
Inventor
牛丸之浩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AGC Ceramics Co Ltd
Original Assignee
Asahi Glass Ceramics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asahi Glass Ceramics Co Ltd filed Critical Asahi Glass Ceramics Co Ltd
Publication of CN101918160A publication Critical patent/CN101918160A/en
Application granted granted Critical
Publication of CN101918160B publication Critical patent/CN101918160B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/18—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents
    • B22C1/181—Cements, oxides or clays

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)

Abstract

Aggregate particles for a mold which exhibit excellent heat resistance and high thermal conductivity and thermal shock resistance and can be used repeatedly are provided as aggregate particles suitable for the production of a mold which exhibits excellent dimensional accuracy and cooling rate, permits easy withdrawal of cast articles, and attains a high recycling ratio and remarkable reduced waste generation. Aggregate particles for a mold, characterized in that the particles comprise Al2O3, ZrO2 and SiO2 as the essential chemical components and the total content of the three components is 50mass% or above and in that the crystalline phase is composed mainly of corundum and baddeleyite and a glass phase is contained in addition to the crystalline phase.

Description

Aggregate particles for molds
Technical field
The present invention relates to hear resistance and thermal shock characteristic good, in heat cycles, also break less, can repeat to utilize again and discarded object reduce effective, be the aggregate particles for molds of main mineral composition with corundum and baddeleyite.
Background technology
The employed sand of casting mold (particle) roughly is divided into the facing sand and the floor sand that is lining in the behind of facing sand of the part that is used for contacting with foundry goods.The facing sand that contacts with foundry goods is through the bonding space that supplies molten metal to flow into that forms of adhesive (furane resins, alkalescent phenol resin etc.).In this specification, below facing sand is called aggregate particles for molds, perhaps abbreviates aggregate particles as.But, do not get rid of with the situation of aggregate particles as floor sand yet.
Because the temperature of molten metal high (1200～1800 ℃) is so require aggregate particles to have enough hear resistances.If hear resistance is low, then therefore the mutual sintering of aggregate particles and combining securely at high temperature not only is difficult to foundry goods is taken out in casting mold, and can't returns to original particle size simply, also is difficult to realize the utilization again of aggregate particles.
Except hear resistance, the coefficient of thermal expansion of aggregate particles is low more, and then the precision of foundry goods is good more, and the thermal conductivity of aggregate particles is high more, then can make foundry goods cool off fully more.If self is destroyed aggregate particles easily, then be difficult to utilize again, so that aggregate particles can not be destroyed is very important yet.Recently, the dustproof countermeasure during as operation adopts the method that the casting mold spray water is cooled off, so resistance to sudden heating also comes into one's own.
In addition,, then can reduce the adhesive use amount, be beneficial to cutting down cost if aggregate particles is difficult for soaking into furane resins, alkalescent phenol resin.Though particularly the furane resins price is more cheap than alkalescent phenol resin, viscosity is low, if the aggregate particles air spots is sliding, then must increase the enough bonding strengths of addition competence exertion, from casting mold on the whole cost rise on the contrary.
In the past, silica sand was widely used as facing sand.But there is following problems in silica sand: thermal expansion is big, and the low precision of foundry goods, and crystalline texture is heated and changes, and is destroyed easily only uses just to have about 10% for 1 time and become discarded object.As the substitute of silica sand, the strong chromium sand of cooling capacity is arranged.But, except demand increases, price is surging, the problem of undersupply, chromium sand is because contain Cr, so discardedly receive the huge restriction based on the environment aspect.
Proposed in the patent documentation 1 with synthetic mullite process spherical particle and about 1600 ℃ burn till and aggregate particles.Though this aggregate particles can be processed the casting mold of intensity higher stable through alkalescent phenol resin; But also have following problems: hear resistance is not enough and be difficult to utilize again; And owing to make through burning till; So the air spots of aggregate particles is sliding, the furane resins low through viscosity can't obtain enough bonding strengths.
The electric fusion character that has proposed in the patent documentation 2 to be got by the fused mass particlized does not come sand.There is following problems under this situation: because SiO 2Therefore more than the content height to 20%, form when fusing, grain refined fibrously easily, the fabrication yield of aggregate particles descends.In addition, also there is following problems: if Fe 2O 3, CaO, MgO, K 2O, TiO 2Deng many, then hear resistance is not enough, and the easily mutual sintering of aggregate particles is difficult to utilize again.
Proposed to make SiO in the patent documentation 3 2Content is formed low than mullite and is the Al of main crystalline phase with the corundum crystalline phase 2O 3-SiO 2Class sand.Yet, there is following problems: owing to be main crystalline phase with the corundum crystalline phase, so resistance to sudden heating is low, if receive thermal shock generation of cracks easily, utilization rate is low again.In addition, comprise in this aggregate particles with oxide and count transition metal-types such as Fe about 10 quality %, alkali metal component etc., also exist hear resistance low, utilize the problem of difficulty again.
In addition, use molding sand, except above-mentioned, also put down in writing zircon sand, olivine etc. in the patent documentation 4 as water-soluble core.Zirconium begins to decompose near about 1500 ℃, the situation such as reaction of silica and foundry goods occur taking place in the casting, therefore has the problem of utilizing difficulty again.Hear resistance such as olivine sand etc. too are not enough.
As having stable on heating material, zirconia class material is arranged, proposed not contain the zirconia class aggregate particles of glassy phase in the patent documentation 5.But this aggregate particles is not owing to contain glassy phase, and particle self is because of following the Volume Changes disintegration of phase transformation, though so as the taking-up property raising of the foundry goods of application target from casting mold, can't utilize again.
Patent documentation 1: the fair 3-47943 communique of Japanese Patent Laid
Patent documentation 2: Japanese Patent Laid is opened the 2003-251434 communique
Patent documentation 3: Japanese Patent Laid is opened the 2005-193267 communique
Patent documentation 4: Japanese Patent Laid is opened the 2004-174598 communique
Patent documentation 5: japanese patent laid-open 6-15404 communique
The announcement of invention
The objective of the invention is to; As be suitable for dimensional accuracy and cooling velocity take out well, easily foundry goods and again utilization rate high, significantly reduced the aggregate particles of the casting mold of the discarded object amount that produces, the aggregate particles for molds that provide that hear resistance is good, thermal conductivity and resistance to impact are high, can repeat to utilize again.
The present invention provides a kind of aggregate particles for molds, it is characterized in that, as chemical composition, with Al 2O 3, ZrO 2And SiO 2Be essential composition, the total amount of said 3 kinds of compositions is more than 50 quality %, and crystalline phase is mainly corundum and baddeleyite, except that said crystalline phase, also comprises glassy phase.
Aggregate particles of the present invention (below be called this aggregate particles) is with Al 2O 3, ZrO 2And SiO 2Be essential composition, the total amount of said 3 kinds of compositions is more than 50 quality %, and crystalline phase is mainly the eutectic of corundum and baddeleyite, so hear resistance is high, and in fact can sintering under environment for use.Therefore, the aggregate particles that has constituted casting mold through adhesive loses bonding force and disperses to revert to original aggregate particles simply after cast, cooling, can easily from casting mold, take out foundry goods.After the use, can reclaim simply as original aggregate particles, can realize utilizing again very efficiently, can significantly reduce discarded object from casting mold from casting mold.
If the TiO of this aggregate particles particularly 2And Fe 2O 3Content in total amount below 3 quality %, then this effect is remarkable.In addition, not comprising in fact under the situation of mullite, can utilize again efficiently too as crystalline phase.
This aggregate particles is because coefficient of thermal expansion is also little, so the dimensional accuracy of foundry goods is good, is suitable for hot investment casting, and has the thermal conductivity that can make the casting composition cooling just.In addition, this aggregate particles is because intensity is also high, and resistance to sudden heating is high, so the thermal shock of aggregate particles hardly can be because of casting the time destroys.Therefore, not only can be used as the dust countermeasure and cool off to the casting mold spray water, and utilize also easily again, discarded object reduces effective.
Therefore this aggregate particles can absorb the Volume Changes that zirconic phase transformation causes in fact owing to comprise glassy phase, does not have Volume Changes as particle integral body, and particle is disintegration voluntarily hardly also.
That is, this aggregate particles can be guaranteed the intensity of particle self when utilizing zirconic characteristic, does not have the change in shape of particle.Therefore, can repeatedly utilize again, can reduce discarded object.In addition, can suppress the generation of dust, the operating environment that also helps casting improves.
If by fused mass particlized cost aggregate particles, then comprise the substrate glass phase, particle surface becomes smoothly, and particle surface does not almost have concavo-convex, even therefore use the low furane resins of viscosity, also can obtain enough bonding strengths through less addition.Therefore, also have the whole cost of casting mold and reduce effect.
The simple declaration of accompanying drawing
Fig. 1 representes the microphotograph of an example of aggregate particles of the present invention.
Fig. 2 is the microphotograph of commercially available mullite class artificial aggregate particle.
Fig. 3 is the sketch map when making aggregate particles of the present invention through fusion method.
The explanation of symbol
1: the melting furnace main body
2: melt electrode
3: fused mass
4: outlet
5: nozzle
7: particle
8: catch
The best mode that carries out an invention
In the aggregate particles for molds of the present invention (below be called this aggregate particles), as chemical composition, with Al 2O 3, ZrO 2And SiO 2Be essential composition, the total amount of said 3 kinds of compositions is more than 50 quality %, and crystalline phase is mainly corundum and baddeleyite.Corundum and baddeleyite form eutectic.Through in the corundum crystalline phase, adding the baddeleyite crystalline phase, low as the resistance to sudden heating of the shortcoming of single alundum, if receive thermal shock then problems such as the utilization rate again when generation of cracks, recycling is low easily improve.This is considered to because through in the corundum crystalline phase, adding baddeleyite crystalline phase, the character that this aggregate particles is endowed tough (toughness).
In this aggregate particles,, better be not contain crystal of andalusite with rich aluminum content in fact as crystalline phase.If do not contain crystal of andalusite with rich aluminum content, then can obtain sufficient hear resistance and thermal conductivity, so aggregate particles in use hardly can sintering, utilizes easily again.In addition, owing to do not contain crystal of andalusite with rich aluminum content, so resistance to sudden heating is good, also is difficult for generation of cracks even receive thermal shock, can repeat to utilize again.
Also have, in this specification, do not contain mullite in fact and be meant to measure and do not observe the peak of tangible crystal of andalusite with rich aluminum content,, the intensity of main peak is made as 100 o'clock relative intensity below 5 even perhaps observe the peak through X-ray diffraction.
In this aggregate particles, as chemical composition, with Al 2O 3, ZrO 2And SiO 2Be essential composition.This is because this aggregate particles mainly is made up of corundum crystalline phase, baddeleyite crystalline phase and glassy phase.In addition, this aggregate particles is with Al 2O 3, ZrO 2And SiO 2These 3 kinds of compositions constitute main components, and the total amount of these 3 kinds of compositions is more than 50 quality % (following with quality % %) slightly.If said total amount is lower than 50%, then may bring into play characteristic as this aggregate particles.In this aggregate particles, if the total amount of said 3 kinds of compositions more than 75%, characteristic good then, therefore preferred, the total amount of more preferably said 3 kinds of compositions is more than 84%.The total amount of said 3 kinds of compositions can be 100%.
In this aggregate particles, if comprise Al in quality % as chemical composition 2O 3: 47～97%, ZrO 2: 1～25%, then can obtain above-mentioned effect more reliably, therefore preferred.In this aggregate particles, if Al 2O 3Content is lower than 47%, and then hear resistance may be not enough, undesirable.In this aggregate particles, if Al 2O 3Content is more than 57%, and more preferably, good especially is Al aspect hear resistance 2O 3Content is more than 65%.
On the other hand, in this aggregate particles, if Al 2O 3Content surpasses 97%, then may correspondingly lose and contain ZrO 2And the effect that obtains is undesirable.In this aggregate particles, Al 2O 3Content better is below 90%, Al 2O 3Content is more preferably below 85%.
In this aggregate particles, if ZrO 2Content is lower than 1%, and then the raising effect of resistance to sudden heating may be not enough, undesirable.In this aggregate particles, ZrO 2Content is more preferably more than 3%, ZrO 2Content is good especially to be more than 6%.
On the other hand, in this aggregate particles, if ZrO 2Content is higher than 30%, then by Al 2O 3-SiO 2-ZrO 2The three component system phasor can know that fusing point reduces on the contrary, refractoriness is low, descends as the characteristic of aggregate particles for molds.But, ZrO 2Content is 36% when following, and refractoriness and mullite class aggregate particles are equal, and the resistance to sudden heating aspect is superior to mullite class artificial aggregate particle, therefore as this aggregate particles, and ZrO 2Content is preferably below 36%.In this aggregate particles, ZrO 2Content better is below 25%, ZrO 2Content is more preferably below 16%.
In this aggregate particles, if make Al in quality % as chemical composition 2O 3And ZrO 2Total amount (Al 2O 3+ ZrO 2) be 83～97%, then show the characteristic that has obtained balance as corundum crystalline phase, baddeleyite crystalline phase, the substrate glass of essential mineral composition, therefore preferred.
If this aggregate particles comprises 2～17% SiO 2Composition, then described substrate glass can wrap up corundum crystalline phase and baddeleyite crystalline phase, can absorb the Volume Changes that the phase transformation of baddeleyite phase causes fully, and is therefore preferred.In this aggregate particles, SiO 2Content better is more than 5%, SiO 2Content is more preferably more than 6%.
On the other hand, if the SiO of this aggregate particles 2Content is higher than 17%, and then hear resistance descends, and fiber increases during manufacturing, and the fabrication yield of aggregate particles reduces, and is therefore undesirable.The SiO of this aggregate particles 2Content better is below 15%, the SiO of this aggregate particles 2Content is more preferably below 13%.
This aggregate particles also comprises glassy phase (the following substrate glass of also claiming) except that the corundum crystalline phase with the baddeleyite crystalline phase.Glassy phase is present between the crystalline phase usually, if the result of medelling ground performance structure observation, then glassy phase exists with the form of parcel crystalline phase.Therefore this aggregate particles can absorb the Volume Changes of following zirconic phase transformation owing to comprise glassy phase, even stand thermal process repeatedly, particle can be because of be full of cracks destroy yet, can be stably as the facing sand recycling of casting mold.
In order to bring into play above-mentioned effect, better be to comprise 2～20% glassy phase in this aggregate particles.Glassy phase in this aggregate particles more preferably 6～17%, good especially is 8～13%.In addition, if such glassy phase is siliceous, the viscosity of the Volume Changes that zirconic phase transformation causes in the time of then can obtaining to be suitable for absorbing high temperature obtains above-mentioned effect easily, so preferred.Also have, in this specification, the chemical composition of glassy phase is removed Al in hypothesis from the chemical composition of particle integral body 2O 3, ZrO 2Remaining part all is to calculate under the condition of glassy phase behind the content.
In this aggregate particles, if (R1) 2Total amount and the SiO of O+ (R2) O 2The mass ratio of composition ((R1) 2O+ (R2) O)/SiO 2Be 5～25%, then the stability of characteristics of substrate glass can also be guaranteed hear resistance, and is therefore preferred, is more preferably 8～15%; R1 is an alkali metal, and R2 is an alkali earth metal.Also have, as R1, can give an example Na, K and Li, as R2, Ca, Mg, Sr and Ba can give an example.
In this aggregate particles, if TiO 2Composition and Fe 2O 3Total amount (the TiO of composition 2+ Fe 2O 3, below TF total amount slightly) count 0～3% with quality %, TiO then 2Composition and Fe 2O 3Composition hardly can with SiO 2Composition and Al 2O 3Generate low-melting compound between the composition, the hear resistance that aggregate particles can not take place descends and problem such as the mutual sintering of aggregate particles when using, and is therefore preferred.In this aggregate particles, the TF total amount better is below 2%, and the TF total amount is more preferably below 1%.The TF total amount is good especially to be below 0.5%.
In this aggregate particles, better be that the total amount of content of the oxide of all transition metal (comprises TiO 2Composition and Fe 2O 3Composition) in quality % below 2%.Remove TiO 2Composition and Fe 2O 3Composition effect separately beyond the composition is not fully aware of, but fusing point ratio aluminum oxide, the zirconia of general transition metal oxide are low, may make characteristic degradation.
In this aggregate particles, the total amount of content that is more preferably the oxide of all transition metals (comprises TiO 2Composition and Fe 2O 3Composition) below 1%, good especially is that the total amount of content of the oxide of all transition metal (comprises TiO 2Composition and Fe 2O 3Composition) below 0.5%.As removing TiO 2, Fe 2O 3The oxide of transition metal in addition, MnO, Co specifically can give an example 2O 3, NiO, CuO, ZnO.
If below 2000 μ m, the mo(U)ld face that contacts with molten metal when then constituting casting mold becomes smoothly the particle diameter of this aggregate particles (below be called particle diameter), can improve the surface accuracy of foundry goods, so preferred.The particle diameter of this aggregate particles is more preferably below 1200 μ m.If it is the particle diameter more than 70% of this aggregate particles is 60～1200 μ m, then mobile, therefore preferred.The particle diameter more than 95% that is more preferably this aggregate particles is 60～1200 μ m.Good especially is that the particle diameter of this aggregate particles is 60～850 μ m.
Also have, in this specification, particle diameter is meant the aperture of JIS sieve.For example, sieve through JIS, aperture minimum in the sieve that particle is residual is as particle diameter.
Because the coefficient of thermal expansion of this aggregate particles is difficult to direct mensuration; So replace with size changing rate; This size changing rate forms the size changing rate after bulk (diameter 3.175mm * high 50mm) also experiences the heat-treat condition of stipulating (under the nitrogen atmosphere, 1150 ℃ * kept 180 seconds) for using organic bond (furane resins) with aggregate particles.The coefficient of thermal expansion of aggregate particles is more little, and then size changing rate is more little.Above-mentioned size changing rate better is below 0.7%, is more preferably below 0.5%.Also have, the size changing rate that is considered to the bigger silica sand of coefficient of thermal expansion is about 1.5%.
If the thermal conductivity of this aggregate particles (normal temperature) is 0.25～0.35W/ (mK), the molten metal after the casting is fully cooled off, and be difficult for producing the space during cooling, therefore preferred.The thermal conductivity of this aggregate particles (normal temperature) better is 0.28～0.31W/ (mK).
If the bulk specific gravity of this aggregate particles is 1.8～2.6; Then with this aggregate particles as facing sand and with silica sand (bulk specific gravity about 1.5) as under the situation of floor sand, facing sand and floor sand easy separation are even distinguish facing sand when utilizing and floor sand carries out operation roughly again; Also easy separation after the end of job; Therefore operation property raising, the productivity aspect is good, so preferred.The bulk specific gravity of this aggregate particles is more preferably 2.0～2.6.The bulk specific gravity of this aggregate particles is good especially to be 2.2～2.4.
As the manufacturing approach of this aggregate particles (below be called this manufacturing approach); Not special qualification the, concrete manufacturing approach can give an example blending and raw material with fusing such as electric arc electric furnace and when coming out of the stove with the method (following fusion method slightly) of grain refined such as air at a high speed or will modulate and the spray method (following sintering process slightly) etc. of formation particle and sintering of the raw material that gets.
Wherein, because the cost aspect is favourable, better be fusion method.Therefore in addition, this aggregate particles of processing through fusion method is level and smooth, does not almost have concavo-convexly at particle surface, even low-viscosity furane resins also need not excessive interpolation just can make it show enough bonding strengths, the cost aspect of casting mold integral body is also favourable.The example of the microphotograph of this aggregate particles of processing through fusion method is shown in Fig. 1.In addition, in order to compare, (ITOCHU Sai La Tektronix Co., Ltd (ITOCHU セ ラ テ Star Network society), trade name: the example of microphotograph Cerabeads) is shown in Fig. 2 with the commercially available synthetic mullite particle that passes through to process.
This manufacturing approach adopts under the situation of fusion method, melts not special qualification of form of the melting furnace of modulated raw material, the melting furnace of the heat forms such as adopting burner, resistance, electric arc, coke of can giving an example.Particularly electrical arc has than is easier to the also high and advantage such as equipment stove is simple, operability is good of the uniformity that obtains high temperature, fused mass, and is therefore preferred.
Inner lining refractory in such melting furnace is not particularly limited, and it is desirable to have the refractory material with the approaching composition of the composition of this aggregate particles, can be the refractory material that contains the impurity lower than the impurity level of this aggregate particles.The alumina type electroforming brick that for example contains the zirconic Zirconia-alumina class electroforming brick about 35% or contain the aluminium oxide 95% or more can not improve the impurity level of casting mold with aggregate, so preferably.
This manufacturing approach adopts under the situation of fusion method, and the operating condition when raw material is carried out fusion in melting furnace is when using the transformer of 500KVA～5000KVA to carry out fusion as power supply usually; If the voltage during with arc heated is made as 80～400 (V); Electric current is made as 500～12000 (A), then can make electrode and fused mass keep suitable distance, suitably protects the refractory material in the electric furnace; Realize stable fusing, therefore preferred.As final melt temperature, better be made as 1850～1950 (℃).
This manufacturing approach adopts under the situation of fusion method, modulation and raw material be melted after, this fused mass is come out of the stove from the plug for outlet of the outer wall that is installed on melting furnace.When coming out of the stove, if melting furnace is tilted, then coming out of the stove becomes easily, so preferred.After fused mass is poured out and is fallen about 100mm from plug for outlet, the injecting condensed air from the rear and grain refined.Surface area increases during grain refined, through contacting and chilling with air, forms good aggregate particles for molds.
The form of its generalities is shown in Fig. 3.Among the figure, 1 expression melting furnace main body, the electrode that 2 expressions are used to carry out fusion, 3 expression fused mass.Melt electrode 2 is connected with power supply through the control system, but not shown.Fused mass 3 is discharged from from outlet 4, through from being arranged at nozzle 5 injecting condensed air or the compressed air and the water at outlet 4 rears, also floats thereby form particle 7, is recovered through catch 8 again.
Under the above-mentioned situation,, better be with the pressure injection more than the 1MPa as compressed-air actuated pressure.Compressed-air actuated pressure is more preferably more than 2MPa, and compressed-air actuated pressure is good especially to be more than 3MPa.On the other hand, if compressed-air actuated pressure is higher than 7MPa, then common equipment can't meet the demands, and better is to make compressed-air actuated pressure be lower than 7MPa therefore.
If more than second, then the particle diameter of the particle more than 70% reaches below the 1.2mm velocity of compressed air at 100m/, form and be suitable as the particle diameter of casting mold with aggregate, therefore preferred.Said flow velocity is more preferably at 130m/ more than second.Also have, in this specification, velocity of compressed air is meant the value with the fused mass position contacting of coming out of the stove from melting furnace, and flow velocity is measured through the common hot-wire anemometer of selling.
If through making a certain amount of water with compressed air flow nozzle simultaneously, process water under high pressure and spray simultaneously with compressed air, then can in grain refined, reduce the temperature of particle, processing is thereafter become easily, so preferably.For abundant chilling particle, cooling water inflow better is more than 1L/ minute, is more preferably more than 2L/ minute.In addition,, need drying process thereafter if hypervolia then soaks casting mold and uses aggregate, thus undesirable, better be below 4L/ minute.
Embodiment
Below, the present invention will be described in more detail through embodiment, but the present invention is not limited to these examples.
Use stove interior diameter 1.5m, high 1.5m, furnace volume 2.5m 3The arc type melting furnace, prepare the transformer of 1100KVA as power supply.Also have, the inner lining refractory of melting furnace uses the Electrocast refractory of alumina content 95%.The electrode of three diameter 15cm of electrodes use.
Raw material chemical composition is in accordance with regulations mixed, in above-mentioned melting furnace, melt.Melting condition is voltage 100V～250V, power 800KW～1000KW, and 1 time input amount 600kg is dropped in the stove with 10 minutes～15 minutes interval in three batches in batches.The total raw material making time is 30 minutes～45 minutes.Fusing time is 80 minutes～100 minutes.
Then, in the compressed air of pressure 4MPa, add 2L/ minute water, spray from nozzle.As shown in Figure 3, spray compressed air at a high speed and particlized from the lower direction liquation of the fused mass of coming out of the stove.Particle reclaims through the metal trap receptacle with the refractory material protection, processes aggregate particles for molds.At this moment velocity of compressed air is second 100m/ second～150m/.The granularity of aggregate particles be more than 85% in the scope of 0.1mm～1.2mm.
[test 1]
The chemical composition and the characteristic of the aggregate particles of gained are shown in table 1.In the table, R 2O representes Na 2O, K 2Alkali metal oxides such as O, RO are represented alkaline earth oxides such as CaO, MgO, and T+F representes TiO 2, Fe 2O 3Total amount.Chemical composition is used fluorescent X-ray device (Co., Ltd. Neo-Confucianism (リ ガ Network society) system, trade name: RIX-2000) measure.Example 1,9,10,11 is a comparative example, and example 2～8 is embodiment.
Through X-ray diffraction device (Co., Ltd. Neo-Confucianism's system, trade name: RINT-2200VK) identified the crystalline phase of each aggregate particles, only observed corundum in the example 1, but observed corundum and baddeleyite in the example 2～8.Example 9 is commercially available mullite class artificial aggregate particle, and mullite is only observed in mineral composition.In addition, example 10 is general silica sand, and quartz is only observed in mineral composition.Example 11 is commercially available chromite particle ((Fe, Mg) Cr 2O 4), constitute by Fe, Mg, Cr oxide, have spinel structure.Sometimes contain part A l and replace Fe.
Based on JIS R2204 the hear resistance of aggregate particles is estimated with refractoriness.In the table ,+1885 ℃ are meant that Seger cone does not fall in the time of 1885 ℃, have the refractoriness more than 1885 ℃.Can know by table, along with ZrO 2The increase of content, refractoriness (hear resistance) descends gradually.
In addition, if aggregate particles destroys easily, then utilize the difficulty that becomes in fact again.So, by the strong hand aggregate particles is implemented to increase the weight of, destroy with which kind of degree for particle and estimate with the particle destructive rate.Specifically, with 100ml (quality W 0) be that the aggregate particles of 53～850 μ m drops into the cylindrical ball mill of diameter 125mm, high 125mm, volume 1.5L with the oxidation aluminum ball of 40 diameter 18～20mm through sieve classification, with the rotating speed of 50RPM the ball mill rotation was pulverized in 240 minutes.
After pulverizing end, measure aggregate particles amount (W through the sieve of 53 μ m 1), with W 1/ W 0* 100 (%) calculate the particle destructive rate.The particle destructive rate is low more, and then the ratio that can utilize again of aggregate particles is high more, and is preferred.Confirm that by table 1 observe as crystalline phase in the example 2～example 8 of corundum and baddeleyite, the particle destructive rate is low, particularly in example 3～example 8, compare that its effect is remarkable, is suitable for utilizing again with commercially available aggregate particles (example 9～example 11).
For the aggregate particles of example 2～example 8, imbed resin and section is carried out mirror ultrafinish, implement structure observation through petrographic microscope.Consequently, confirm in corundum phase and baddeleyite eutectiferous nature of glass that exists on every side mutually.
[table 1]
Figure BPA00001186259100101
[test 2]
Below, in order to confirm the influence of suitable dioxide-containing silica, make SiO as far as possible 2, Al 2O 3Composition in addition remains unchanged, through making aggregate particles with test 1 same method for making, condition.For the aggregate particles of gained, measure bulk specific gravity and refractoriness, its result is shown in table 2 with chemical composition.Also have, bulk specific gravity is calculated as follows: aggregate particles is added beaker (volume 100mL) and repeats to rap 20 times, and the quality when reaching 100mL by the volume after rapping is calculated.
Can know that by table 2 bulk specific gravity increases along with the increase of dioxide-containing silica, but after reaching more than the certain value, reduce gradually on the contrary.Observe a part of hollow-particle in example 12, the example 13.On the other hand, bulk specific gravity reduces along with the increase of silica volume to be considered to reduce gradually as the aluminium oxide of the element heavier than silica.Also have, through microscopic examination the tissue of example 12～example 17, in all samples, all observe corundum phase, baddeleyite phase, and around it, observe glassy phase.In addition, the amount of glassy phase increases with dioxide-containing silica.
In addition, the refractoriness as stable on heating index reduces along with the increase of silica volume gradually.Also have, in example 16, the example 17, observe and except particle, also generate fiber.
[table 2]
[test 3]
In order to investigate TiO 2, Fe 2O 3Influence, make SiO 2Substantial constant is 10%, and other compositions are also remained unchanged as far as possible, through making aggregate particles with test 1 same method for making, condition.Chemical composition is shown in table 3.Also have, each particle confirms corundum crystalline phase and baddeleyite crystalline phase by X-ray diffraction.In addition, confirm eutectiferous glassy phase that exists on every side through the structure observation that adopts petrographic microscope in corundum crystalline phase and baddeleyite crystalline phase.
Then, to the hear resistance (with the refractoriness evaluation) of made aggregate particles and particle again usability estimate, be shown in table 3 in the lump.The particle evaluation of usability again is in following purpose: judge aggregate particles is being used for casting mold; After molten metal cast in casting mold, cools off; During from casting mold taking-up foundry goods; Aggregate particles does not solidify and can break simply, can easily take out foundry goods, and whether can carry out the utilization again of aggregate particles simply.
The particle evaluation method of usability again is in the other platinum ware of preparing of each aggregate particles input of 30g, to heat with electric furnace.Heating condition is cold for heating up and in stove, put naturally after 1 hour 1500 ℃ of maintenances with 300 ℃/hour, with 3 grades of states of estimating the aggregate particles that takes out of A～C.Also have, even in order to make condition determination, each aggregate particles is carried out classification and adjusts granularity to 0.3mm～0.425mm, supply in test.
A is meant that aggregate particles does not form piece each other, if inclination platinum ware, the state that aggregate particles can move with the state of particle; Though B is meant aggregate particles and is solidified to form fritter slightly, if with the hand touching, then easily reverts to the state of aggregate particles; C is meant that aggregate particles is solidified to form piece, only through can't breaking piece with hand touching, if firmly then can break the state of piece.As aggregate particles, it is desirable to the state of A, B.
Can be known that by table 3 the TF total amount is 3% when following, particle usability again is A, B, and aggregate particles is suitable for the casting mold purposes.
[table 3]
Figure BPA00001186259100121
[test 4]
Measure the thermal conductivity of aggregate particles.The result is illustrated with in the past silica sand, chromite, the artificial particle of mullite class.Also have, Determination of Thermal Conductivity is implemented according to JIS R2618 " test method of the thermal conductivity of the employing heat-pole method of refractory brick ".The container that adds aggregate particles adopt with the thermal insulation brick (Chisso Laiter Industry Co., Ltd. (イ ソ ラ イ ト society) system, trade name: B6) empty and stay 10mm on every side and following container, add a cover with insulating brick of the same race and to supply in mensuration.Aggregate particles is filled up down container, add a cover, measure.The result is shown in table 4.
Can know that by table the thermal conductivity of aggregate particles of the present invention reduces with the increase of zirconia content.As thermal conductivity, the level of chromite particle (0.29W/ (mK)) is a target, if ZrO 2Content below 20%, then can obtain the thermal conductivity with chromite particle peer-level about.On the other hand, the thermal conductivity of the mullite class artificial aggregate particle of at present commercially available example 9 is lower than aggregate particles of the present invention.
[table 4]
Sample Thermal conductivity (W/ (mK))
Silica sand 0.259
Chromite 0.288
Mullite class artificial aggregate particle 0.216
Example 4 (ZrO 2：8.8％) 0.310
Example 8 (ZrO 2：36％) 0.257
Example 15 (ZrO 2：19.4％) 0.297
[test 5]
Below, because the matching degree of these aggregate particles and the employed adhesive of casting mold is also very important, so bonding strength is estimated with compressive strength.The aggregate particles are added and mixed in a predetermined amount of binder and curing agent, forming a diameter of 5cm, a cylindrical high-cm as a sample, after 24 hours by measuring the force sensor (east of the Precision Industrial Co., Ltd. (east of the Precision Industry Inc.), trade name: H-3000D, maximum load 3 tons) to 10mm / min is applied to the speed increase in the height direction along the cylinder, the compression strength was measured.
The amount of the binder is added, relative to the total percentage of aggregate particles in an applied furan resin (Physical and Chemical Industry Co., Ltd. Kobe (Kobe Li Chemical Co.), trade name: X-furan? ST-71E) of 1%, the curing furan resin agent is added with respect to the percentage of total other than a furan resin is 40%.(Kobe physics and chemistry is learned Industrial Co., Ltd's system, trade name: in the time of 510A), be 1.4% with respect to aggregate particles to add proportional meter, it is 40% with respect to alkalescent phenol resin to add proportional meter that alkalescent phenol resin uses curing agent to adopt alkalescent phenol resin.
In the aggregate particles that example 3～example 9 is formed, the affirmation compressive strength is 5～6MPa, obtains to be enough to the intensity as casting mold.Also have, through microscopic examination the aggregate particles of example 3～example 9, confirm that particle surface that kind as shown in Figure 1 is level and smooth.Think because particle surface is level and smooth, even therefore low-viscosity furane resins also show enough bonding strengths.
The possibility of utilizing on the industry
Through the present invention; As be suitable for dimensional accuracy and cooling velocity take out well, easily foundry goods and again utilization rate high, significantly reduced the aggregate particles of the casting mold of the discarded object amount that produces, the aggregate particles for molds that can provide that hear resistance is good, thermal conductivity and resistance to impact are high, can repeat to utilize again.Through using this aggregate particles, can reduce discarded object from casting mold, help casting on-the-spot operating environment simultaneously and improve.
Quote all the elements of Japanese patent application 2008-011852 number specification, claims, accompanying drawing and the summary of filing an application on January 22nd, 2008 here, adopt as the announcement of specification of the present invention.

Claims (9)

1. an aggregate particles for molds is characterized in that, as chemical composition, with Al 2O 3, ZrO 2And SiO 2Be essential composition, the total amount of said 3 kinds of compositions is more than 50 quality %, and crystalline phase is mainly corundum and baddeleyite, except that said crystalline phase, also comprises glassy phase.
2. aggregate particles for molds as claimed in claim 1 is characterized in that, in quality %, comprises Al 2O 3: 47～97%, ZrO 2: 1～36%, SiO 2: 2～17%.
3. according to claim 1 or claim 2 aggregate particles for molds is characterized in that, (R1) 2Total amount and the SiO of O+ (R2) O 2The mass ratio of composition ((R1) 2O+ (R2) O)/SiO 2Be 5～25 quality %; R1 is an alkali metal, and R2 is an alkali earth metal.
4. according to claim 1 or claim 2 aggregate particles for molds is characterized in that TiO 2And Fe 2O 3Total amount be 0～3 quality %.
5. according to claim 1 or claim 2 aggregate particles for molds is characterized in that, corundum and baddeleyite form eutectic.
6. according to claim 1 or claim 2 aggregate particles for molds is characterized in that crystalline phase does not contain crystal of andalusite with rich aluminum content.
7. according to claim 1 or claim 2 aggregate particles for molds is characterized in that bulk specific gravity is 1.8～2.6.
8. aggregate particles for molds as claimed in claim 4 is characterized in that, comprises TiO 2Composition and Fe 2O 3The total amount of the content of the oxide of all transition metals of composition is below 3 quality %.
9. the manufacturing approach of an aggregate particles for molds is characterized in that, makes each the described aggregate particles for molds in the claim 1～8 by the fused mass particlized.
CN200980103162.5A 2008-01-22 2009-01-22 Aggregate particles for molds Active CN101918160B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2008-011852 2008-01-22
JP2008011852 2008-01-22
PCT/JP2009/050990 WO2009093663A1 (en) 2008-01-22 2009-01-22 Aggregate particles for molds

Publications (2)

Publication Number Publication Date
CN101918160A CN101918160A (en) 2010-12-15
CN101918160B true CN101918160B (en) 2012-11-28

Family

ID=40901168

Family Applications (1)

Application Number Title Priority Date Filing Date
CN200980103162.5A Active CN101918160B (en) 2008-01-22 2009-01-22 Aggregate particles for molds

Country Status (3)

Country Link
JP (1) JP5507262B2 (en)
CN (1) CN101918160B (en)
WO (1) WO2009093663A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5430342B2 (en) * 2009-10-22 2014-02-26 株式会社神戸製鋼所 Foundry sand and casting mold
JP5876235B2 (en) * 2010-06-09 2016-03-02 Ａｇｃセラミックス株式会社 Lightweight fireproof aggregate
CN102924094A (en) * 2011-08-08 2013-02-13 旭硝子陶瓷株式会社 Aggregate particles and making method of the same
JP5980612B2 (en) * 2011-08-08 2016-08-31 Ａｇｃセラミックス株式会社 Aggregate particles and method for producing the same
JPWO2013042777A1 (en) * 2011-09-22 2015-03-26 旭硝子株式会社 Method for producing positive electrode material for secondary battery
EP3626691A4 (en) * 2017-05-19 2021-03-17 AGC Ceramics Co., Ltd. Material for molding, functional agent, molded product, and product
CN107445614A (en) * 2017-08-22 2017-12-08 汉川市石金科技有限公司 A kind of compound zirconium oxide powder and preparation method thereof
CN107661960B (en) * 2017-11-27 2019-08-20 河南博威热能科技有限公司 A kind of glass matrix moulding sand for casting
CN107824742B (en) * 2017-11-27 2019-08-02 河南博威热能科技有限公司 A kind of amorphous state moulding sand for casting and its manufacturing method
CN113105254B (en) * 2021-03-29 2022-10-21 彰武县联信铸造硅砂有限公司 Novel ceramic sand and preparation method thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1041300A (en) * 1988-09-30 1990-04-18 太原矿山机器厂 The production method of sand core for investment casting
CN1289655A (en) * 1993-12-28 2001-04-04 日本铸造技术咨询公司 Method for making formed refractory casting mould with core installed

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2669920B1 (en) * 1990-12-04 1993-01-22 Pechiney Rech Gie PROCESS FOR THE MANUFACTURE OF REFRACTORY MATERIALS AND THEIR APPLICATIONS IN FOUNDRY OF CORROSIVE ALLOYS.
EP1266706A1 (en) * 2001-06-13 2002-12-18 Siemens Aktiengesellschaft Casting apparatus, process for producing a casting apparatus and its use

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1041300A (en) * 1988-09-30 1990-04-18 太原矿山机器厂 The production method of sand core for investment casting
CN1289655A (en) * 1993-12-28 2001-04-04 日本铸造技术咨询公司 Method for making formed refractory casting mould with core installed

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JP特开平4-321551A 1992.11.11

Also Published As

Publication number Publication date
WO2009093663A1 (en) 2009-07-30
JPWO2009093663A1 (en) 2011-05-26
CN101918160A (en) 2010-12-15
JP5507262B2 (en) 2014-05-28

Similar Documents

Publication Publication Date Title
CN101918160B (en) Aggregate particles for molds
KR101322442B1 (en) Alumina - titanium oxide - zirconia fused grain
US8980775B2 (en) Powder for glass-ceramic dry refractory material
CN101883744B (en) Process for production of refractory particles
CN100564318C (en) A kind of alumina-silica refractory brick that contains light porous aggregate and preparation method thereof
US5053366A (en) Refractory compositions containing monoclinic zirconia and articles formed from these compositions exhibiting improved mechanical strength at high temperatures and improved resistance to thermal shocks
US20120309608A1 (en) Powder for dry refractory material
JPS596272B2 (en) Unfired refractory composition
CN100381400C (en) Magnesia profile sand for preparing founding aluminium oxide refractory material
CN108137412B (en) Fused zirconia-spinel particles and refractory products obtained from said particles
CN102924094A (en) Aggregate particles and making method of the same
KR20180052717A (en) Magnesium-rich fused magnesium aluminate particles
JP2013043180A (en) Molding sand and method for producing the same
CN102432307A (en) Powder composition for refractory castable and refractory castable equipped therewith
JP5980612B2 (en) Aggregate particles and method for producing the same
CN102241510A (en) Electric melting method for manufacturing yttria stabilized zirconia
JP2016199449A (en) Monolithic refractory composition and monolithic refractory
CN102686340A (en) Filter for aluminum melt
CN102336575B (en) Adiabatic castable powder composition and the adiabatic castable using it
JP2001302364A (en) Alumina-magnesia-based castable refractory containing zirconium oxide and molten metal vessel for metal refining
TWI733332B (en) High alumina fusion casting refractory and manufacturing method thereof
JP5745158B2 (en) ATZ fused particles
CN107954606A (en) Glass ceramics and its preparation method and application
CN100453987C (en) Heat-resistance protective tube and its mfg. method
CN102344290B (en) Light-weight refractory aggregate

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant