EP2163328A1 - Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of >= approx. 0.25 weight % to approx 0.9 weight % - Google Patents
Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of >= approx. 0.25 weight % to approx 0.9 weight % Download PDFInfo
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- EP2163328A1 EP2163328A1 EP08015735A EP08015735A EP2163328A1 EP 2163328 A1 EP2163328 A1 EP 2163328A1 EP 08015735 A EP08015735 A EP 08015735A EP 08015735 A EP08015735 A EP 08015735A EP 2163328 A1 EP2163328 A1 EP 2163328A1
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- EP
- European Patent Office
- Prior art keywords
- core
- sand
- molding
- foundry sand
- casting
- 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.)
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Classifications
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- 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
- B22C1/186—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 contaming ammonium or metal silicates, silica sols
- B22C1/188—Alkali metal silicates
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- 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
Definitions
- the invention relates to a core or molding sand for the production of cores and casting molds, for casting molten metal, which comprises a molding base material (eg quartz sand, chrome ore sand, zircon sand, olivine sand, synthetic sands) containing water glass and wherein the core or molding sand a Water content in the range of ⁇ about 0.25 wt .-% to about 0.9 wt .-%, based on the total weight of the core and molding sand has. Furthermore, the invention relates to a method for producing such a core or foundry sand and a method for producing a core or a casting mold with this core or molding sand and its use.
- a molding base material eg quartz sand, chrome ore sand, zircon sand, olivine sand, synthetic sands
- the core or molding sand a Water content in the range of ⁇ about 0.25 wt .-% to
- Core or molding sands for the production of cores or other casting molds are known. Usually, these are first brought into the desired shape by a die-forming tool, such as a core tool, filled with the core or molding sand and then the core or molding sand is compacted and cured. After opening the tool, the desired molding, such as a casting core, can be removed. Using this casting core, metal melts, including aluminum alloy melts, can then be poured into the desired shape. After the molten metal has solidified, the casting core or the casting mold can be removed, for example by means of shaking. By shaking the previously solid and stable G thinkkern- / form decays.
- a known process for the production of core or foundry sand is also called "croning process” according to its inventor.
- a fine-grained quartz sand is used as the molding material, in which each sand grain is coated with a thermoplastic phenolic resin layer.
- the phenolic resins are solid at room temperature before heating in the uncured state. If the core or foundry sand is now introduced into a molding cavity, such as a die-forming tool, such as a core tool, and heated to 250 ° C. to 300 ° C., the binder film melts and binder bridges are formed by polycondensation Conclusion of the polycondensation reaction are solid and have thermosetting properties.
- the finished core or the finished shape can be removed from the tool.
- the core or molding sand used in the croning process has the advantage over other common core / mold making processes (eg cold box, hot box, furan resin, water glass CO 2 process) that the curing reaction is in contrast to the previously mentioned processes not directly after mixing, but only after renewed heat supply (250 ° C-300 ° C) begins.
- the shelf life of the ready-mixed core or foundry sand is virtually unlimited when properly stored.
- the core or molding sand exhibits good flowability, good image accuracy, high dimensional accuracy, high edge sharpness and high surface quality.
- a disadvantage of the croning process is that the tool temperature for producing the cores or the moldings from the core or molding sand must be selected to be extremely high, which causes a high energy requirement.
- the phenolic resin burns to release Harmful and polluting emissions (eg mono- and polycyclic aromatics).
- Harmful and polluting emissions eg mono- and polycyclic aromatics.
- the disposal of the used core or molded parts after casting is an environmental problem, since they can be deposited only with high financial cost (hazardous waste landfill). Even a possible thermal regeneration is associated with extremely high costs and environmental pollution.
- a molding material with an inorganic, for example. Water glass-based binder.
- the molding material is mixed with an aqueous solution of water glass and injected immediately ansch manend in a mold.
- a molding heat can be supplied to solidify by dehydration, the core or molding sand (physical hardening).
- the core or molding sand will be gassed with CO 2 to chemically cure the molding.
- DE 196 32 293 discloses a method for producing core moldings for the foundry technology, wherein a mixture of an inorganic refractory molding sand and a water-based inorganic binder filled in a core box and then withdrawn to solidify the core, the water or is gassed with CO 2 .
- a waterglass-based binder system useful in these processes is disclosed in U.S. Pat DE 199 51 622 described. This consists of an aqueous alkali silicate solution, wherein it additionally contains a hygroscopic base. The solids content of the alkali metal silicate solutions used is described as 20 to 40%.
- EP 0 917 499 a method for producing core moldings for the foundry technique, in which a mixture of an inorganic, refractory molding sand and a waterglass-based inorganic binder is used under certain conditions in forming the core molding. It is also in EP 0 917 499 a method for producing a circulating core sand described consisting of residues of old cores from core moldings. This means that this sand has passed through the casting process at least once, ie the cores were poured, gutted and then singled out.
- an aqueous alkali metal silicate solution is mixed with a molding material and then this moist mixture is introduced directly into a molding tool.
- a disadvantage of this method is that after mixing the molding base material and the aqueous alkali silicate solution obtained is not storage-stable or only limited shelf life, as in a closed molding material container. This means that the mixture must be prepared immediately before the production of the molding and then used immediately.
- the core or molding sand of mold base material and an aqueous alkali silicate solution is only conditionally free flowing and therefore additional measures must be taken to ensure that the core or molding sand fills all the cavities of a mold, such as by applying negative pressure or Shaking the mold.
- additional measures must be taken to ensure that the core or molding sand fills all the cavities of a mold, such as by applying negative pressure or Shaking the mold.
- the in EP 0 917 499 described core recirculating sand is unsuitable to obtain a storage stability combined with good properties in producing a core molding, since the core sand is not directly used for the production of core moldings.
- the present invention is therefore based on the object to provide a core or molding sand available, which overcomes the disadvantages of conventional core or molding sand and in particular to provide a core or molding sand available, which is storage stable and immediately, without further Steps can be used to manufacture a molded article without health or environmental risks associated with its use. Furthermore, the core or molding sand should allow easy and safe filling into a mold.
- a core or molding sand for cores and casting molds for casting molten metal comprising a molding base material coated or mixed with water glass and having a water content in the range of ⁇ about 0.25 wt% to about 0 , 9 wt .-%, based on the total weight of the core and molding sand has.
- the water content is understood to include the upper and lower values of the region (s).
- a method for producing a core or foundry sand according to the invention is provided and a method for producing a core and a casting mold for casting molten metal using the core or foundry sand according to the invention.
- the water glass used according to the invention preferably has a dynamic viscosity of ⁇ 10 2 Pa * s, more preferably 2,5 10 2.5 Pa * s, in particular of ⁇ 10 3 Pa * s.
- Water glass with a dynamic viscosity of ⁇ 10 2 Pa * s is solid. This means that the core or foundry sand according to the invention is coated or mixed in particular with solid water glass.
- the core and foundry sand according to the invention has a water content in the range of ⁇ about 0.25 wt .-% to about 0.9 wt .-%, based on the total weight of the core and foundry sand, preferably from about ⁇ about 0.3 Wt .-% to about 0.9 wt .-%, in particular from ⁇ about 0.3 wt .-% to about 0.9 wt .-%, based on the total weight of the core and foundry sand.
- the water content of the core and molding sand is less than about 0.25 wt .-%, based on the total weight of the core and foundry sand, then no core and molding sand is obtained, which can be used immediately, in particular no core and molding sand which would be useful in the inventive method of making a core and mold described below.
- the water content is over about 0.9% by weight, no storage-stable core or molding sand is obtained.
- the Water content is calculated according to the VDG leaflet " Testing of clay-bonded plastics Determination of water content "P 32, Section 4.1., April 1997 certainly.
- coated means that the individual particles of the molding material are substantially uniformly coated by a waterglass coating.
- the term is not to be understood as meaning that each individual particle of the molding material must be coated separately with a waterglass coating, but also includes embodiments in which particles are only partially coated or several particles are coated together by a waterglass coating.
- mixed means that the water glass is firmly mixed (homogenized) with the molding base material.
- the core or molding sand according to the invention is characterized in that it is dry and free-flowing.
- the determination of the flowability is carried out, for example, with measuring funnels or special pourability testing equipment, such as from the company Karg Industrietechnik, wherein the trickle time is measured at a given mass or given volume as a comparison indicator and specified in seconds.
- the core and molding sand of the present invention preferably has a flowability of ⁇ about 4 seconds, more preferably ⁇ about 3.5 seconds, measured at a sample amount of 350 g in a measuring funnel having an inner diameter at its upper, wide edge of 90 mm and a funnel height of a total of 95 mm and a length of 32 mm and an inner diameter of the spout of 15 mm at room temperature of about 20 ° C.
- the water glass with which the molding base material is coated or mixed preferably comprises additional additives selected from the group consisting of adhesion promoters, flow improvers, casting surface improvers and release agents.
- the additive is preferably selected from the group consisting of sodium hydroxide solution, amorphous SiO 2 , graphite, silicone oil emulsion, stearates, various oils, surfactants, aluminum oxides, iron oxides, talc, boron nitrides, magnesium oxide and various metal oxides.
- the adhesion promoter is preferably selected from sodium hydroxide solution, hygroscopic bases and / or surfactants.
- the flow improvers used are preferably additives selected from the group consisting of amorphous SiO 2 , graphite, silicone oil, silicone oil emulsion, stearates, various oils and surfactants.
- As the improving agent for the casting surface there are preferably used additives selected from the group consisting of amorphous SiO 2 , graphite, aluminum oxides, iron oxides, talc, boron nitrides, magnesium oxide and various metal oxides.
- the release agents used are preferably additives selected from the group consisting of silicone oil, silicone oil emulsion, aluminum oxides, iron oxides, talc, graphite and boron nitride.
- the drying agent and / or flow aid used is preferably dry, amorphous SiO 2 .
- the molding material used is preferably a refractory mineral or synthetic sand, in particular quartz sand, zircon sand, chrome ore sand, almost spherical sand, olivine sand or mixtures thereof.
- the molding material preferably has a mean particle size of about 0.08 mm to 0.6 mm, in particular from 0.08 mm to 0.5 mm.
- further adjuvants can be added to the coated core or foundry sand according to the invention, such as flow aids, drying agents, flow improvers, improvers for the casting surface and / or release agents.
- the other auxiliaries are preferably selected from the group consisting of dry amorphous SiO 2 , aluminum oxides, iron oxides, talc, graphite and boron nitrides. The properties of the other adjuvants are as described above with respect to their addition to the waterglass coating.
- a total amount of additives (without water glass) of up to 4 wt .-%, in particular up to 3 wt .-%, based on the total weight of the core or foundry sand added.
- the molding sand according to the invention preferably does not comprise any organic additives or additives.
- the core or foundry sand according to the invention is preferably produced in a process comprising the following steps: a) a molding base material according to the invention is provided, b) an aqueous solution of waterglass and / or dry waterglass powder is added and c) the core or molding sand mixed, dried and singed.
- a mixer is preferably first filled with the basic molding material, which ensures the homogenization of the core or molding sand with the binder components and optionally the additives.
- the basic molding material preference is given to using wing mixers, oscillating mixers, intensive mixers, vortex mixers or vertical rolling gears.
- an aqueous solution of water glass and / or dry / solid water glass and optionally further additives may then be added.
- an aqueous solution preferably has a dynamic viscosity of up to 10 2 Pa * s.
- the term "aqueous solution” includes both liquid, viscous and pasty water glasses.
- a dry / solid water glass is added, it preferably has a dynamic viscosity of more than 10 2 Pa * s. It is also possible to add a mixture of different water glasses and / or a mixture of an aqueous solution of water glass and dry / solid water glass.
- the water glass used is an alkali silicate solution of the general composition xSiO 2 ⁇ yM 2 O ⁇ nH 2 O, wherein M is selected from Li + , K + or Na + and x: y preferably about 1: 1 to 4: 1, in particular about 2: 1 to 3.5: 1 (where the ratio x: y is also the modulus of the water glass, ie the SiO 2 : M 2 O ratio).
- the index n determines the amount of H 2 O in the solution.
- an aqueous solution of alkali silicate having a solid content of not more than about 60% by weight based on the entire solution is preferably used.
- an adhesion promoter may preferably be added in an amount of up to about 0.5% by weight, preferably about 0.1 to about 0.2% by weight, based on the weight of the masterbatch.
- the adhesion promoter is preferably an aqueous solution of sodium hydroxide solution, in particular about 10 to about 50%, particularly preferably a 30% sodium hydroxide solution.
- the adhesion promoter is added to the molding base material in step b) before the addition of the aqueous solution of water glass.
- the aqueous solution of water glass is then added to the addition of the adhesion promoter.
- a flow improver or casting surface improver is preferably added in amounts up to about 3% by weight, based on the weight of the masterbatch.
- Particularly preferred is first an aqueous suspension of amorphous SiO 2 , preferably in an amount up to about 3 wt .-%, in particular about 0.6 to about 1.0 wt .-%, based on the weight of the mold base material, and then preferred an aqueous suspension of amorphous SiO 2 and graphite, preferably in an amount of up to about 3 wt .-%, in particular about 0.6 to about 1.0 wt .-%, based on the weight of the molding base material, added thereto.
- the aqueous suspension is preferably about 10 to about 80%, in particular about 30 to about 60% pure.
- a flow improver and / or release agent is preferably added in an amount of up to about 1% by weight, in particular up to about 0.8% by weight, based on the weight of the molding base material Silicone oil and / or a silicone oil emulsion.
- step b) is carried out by first an adhesion promoter, preferably sodium hydroxide solution, then the binder, namely the optionally aqueous solution of waterglass, then a flow improver and / or improver for the casting surface, particularly preferably an aqueous suspension of amorphous SiO 2, and then amorphous SiO 2 and graphite are added, followed by the addition of a flow improver and / or release agent, particularly silicone oil or a silicone oil emulsion.
- an adhesion promoter preferably sodium hydroxide solution
- the binder namely the optionally aqueous solution of waterglass
- a flow improver and / or improver for the casting surface particularly preferably an aqueous suspension of amorphous SiO 2
- amorphous SiO 2 and graphite are added
- a flow improver and / or release agent particularly silicone oil or a silicone oil emulsion.
- dry / solid water glass or a mixture of aqueous and dry / solid water glass may already be added in step b), whereby in the case of addition of dry / solid water glass it is not necessary to dry the mixture.
- the mixing serves to produce as uniform a mixture as possible.
- step c) the core or molding sand is then dried.
- the friction energy introduced into the mixture by the mixer is preferably used.
- a wing mixer which has a rotational speed of 160 rpm and it is preferably mixed for one hour.
- the mixture is deprived of water.
- the water content of the water glass with which the molding base material is coated or mixed by mixing and dehydration is adjusted to a content in the range of ⁇ about 0.25 wt% to about 0.9 wt%.
- a core or molding sand is obtained, which is provided with a solid coating of water glass.
- the molding base material obtained by the process according to the invention is thus coated with waterglass, at the same time a free-flowing core or molding sand is obtained, which is also storage stable.
- the drying can be carried out with any device as long as it is ensured that the water content of the water glass coating of the molding base material is maintained.
- An external heating, hot air, radiant heating, vacuum, or negative pressure or a heating jacket can preferably also be used for this purpose.
- each adjuvant can be added to the core or molding sand, such as flow aids, desiccants, flow improvers, casting surface improvers, or release agents.
- each adjuvant will contain an amount of up to about 2% by weight, based on the weight of the masterbatch.
- At least one further additive selected from the group consisting of adhesion promoters, flow improvers, casting surface improvers and release agents may be added to the masterbatch before step c).
- at least one further adjuvant selected from the group consisting of flow aids, drying agents, flow improvers, casting surface improvers and release agents may preferably be added to the core or molding sand after step c).
- the core or molding sand thus obtained can then be screened for the deposition of agglomerates.
- the resulting core or foundry sand according to the invention can then be used directly to produce a core or a molded part.
- the core or foundry sand according to the invention can also be stored loose or packed and can be stored almost indefinitely because of its consistency.
- the core or foundry sand according to the invention can be prepared separately from a method for producing the molded part and stored, packaged or transported, which means a considerable work and time savings for the foundries and the manufacturer of core and moldings.
- the core and foundry sand according to the invention preferably does not comprise any organic additives or additives, so that no environmentally harmful substances are formed when it is used.
- the core or foundry sand according to the invention is then advantageously used in a method for producing a casting mold or a core or core molding for casting molten metal.
- a core or molding sand according to the invention is initially provided for the core production a) and b) a core tool or tool is filled with the core or molding sand according to the invention.
- the filling can eg be carried out by trickling, blowing and / or shooting with a carrier medium such as compressed air, hot air or steam. This can be done by means of a commercial core shooter or by suction and subsequent bubbles.
- the core or molding sand is then compressed in the core tool.
- the core or molding sand in the tool is brought into contact with at least one hardening agent, preferably water, water-containing liquids and / or chemical hardening agents such as CO 2 .
- at least one hardening agent preferably water, water-containing liquids and / or chemical hardening agents such as CO 2 .
- steam is used for this purpose.
- the water vapor is preferably introduced into the tool.
- the water vapor can be introduced into the molding material, for example, by means of a gassing plate via the injections and / or through the steam connection to the tool vents.
- a water vapor-air mixture is used, which preferably contains an amount of water to about 6 wt .-% based on the mold base, in particular 3-4 wt .-%.
- the pressure is preferably up to about 10 bar, in particular about 0.5 to about 1.5 bar.
- the core or molding sand according to the invention is thus brought into a core tool or molding tool, preferably by firing or pouring, and then preferably compacted.
- the compaction is preferably carried out by shaking and pressing.
- the core or molding sand in the tool is preferably brought into contact with an aqueous solution or water.
- steam is used for this purpose.
- the contacting with water, in particular water vapor can preferably be carried out during step b), for example, in a temporal relationship with the filling, in particular the firing of the core or foundry sand, or after its filling in a separate step c).
- the waterglass coating of the core or molding sand according to the invention is dissolved and softened.
- binder bridges form between the particles of the core or foundry sand.
- the core is solidified, in particular by removing the water or by chemical means.
- This can preferably be achieved by subsequently introducing energy into the core in the form of a heat transfer medium, such as in the form of hot air or a water vapor-air mixture which is passed through the core.
- the water may be removed by applying a vacuum to the tool. By removing the water, the water glass solidifies and it is a stable, solid molding obtained. It is thus a substantially physical process without the need for additional chemical reactions.
- CO 2 can be used as the hardening agent and the solidification is thus carried out essentially chemically.
- both methods for solidification can be carried out either simultaneously or also successively. After hardening or solidifying (drying) of the molding, the tool can be opened and the finished Fonnteil, eg. A core removed.
- the core within the core tool may only be preconsolidated, for example pre-dried, until the core has sufficient strength to be removed from the core tool. Thereafter, the preconsolidated core may be further solidified outside the core tool, in particular, the predried core may be finish dried in, for example, a microwave, an oven, or a drying chamber.
- the tool for forming the core or molding during all steps b) to c) to a temperature of from room temperature or about 20 ° C to about 200 ° C, more preferably about 70 ° C to about 160 ° C, heated in particular about 70 to about 120 ° C.
- the water immediately after filling and contacting the core or molding sand with water, the water can then be withdrawn, for example, by the tool being heated to said temperatures.
- the water may additionally or alternatively be withdrawn using hot air and / or warm carrier gas and / or by applying a negative pressure / vacuum.
- the duration of contact with water may be carried out, for example, for about 5 minutes to about 3 hours.
- the core or mold of the present invention preferably has a flexural strength of at least about 300 N / cm 2 , more preferably at least about 400 N / cm 2, and most preferably at least about 450 N / cm 2 .
- the flexural strength of the core is tested in accordance with the VDG leaflet P 72 "Binder Testing, Testing of Cold-curing, Resin-Bonded Wet Forming Materials with Hardening Additive" dated October 1999.
- Such a manufactured core according to the invention can then be used to produce a casting mold for casting molten metal.
- the inventive method and molding sand have the advantage that the molding sand according to the invention due to its flowability has a similar shooting behavior, such as the core or molding sand used in the croning process described above and thus reliably without additional steps in a mold or core tool can be introduced.
- the process of the invention can be carried out by purely physical steps for solidification of the molded part, wherein no environmentally harmful substances are formed become. This is advantageous because when pouring the liquid metal no elaborate extraction systems must be kept in the foundry and the employees are exposed to no hazardous gases such as phenolic compounds. The recycling and disposal of the used inorganic core or foundry sand are easily possible.
- the invention relates to a core tool or molding tool for producing a core molding or a casting mold.
- the core tool is equipped in accordance with conventional core tools suitable for making a casting mold, wherein at least one port suitable for introducing a curing agent such as water vapor or a chemical curing agent is provided.
- a curing agent such as water vapor or a chemical curing agent
- further openings may be provided in the core tool, from which the curing agent, such as the water vapor or chemical curing agent, may again escape.
- the core tool comprises a suitable mold for producing the desired core molding or mold and at least one connection for introducing or injecting the core and molding sand, and at least one connection for introducing a curing agent, such as water vapor or a chemical curing agent.
- the terminals may also be provided together in one terminal, i. a connector which is suitable both for injecting the core and molding sand and the curing agent, such as water and / or the chemical curing agent.
- the connection may also be a gassing plate, at the same time the injections and / or a separate steam connection to the tool vents.
- the core tool is preferably designed in two parts in order to simply remove the core blank or the casting mold after production.
- Bindergatt mich ⁇ Mold base material Quartz sand H32 1. bonding agent: 0.1% by weight NaOH 2. Binder: 3.0% by weight of water glass (modulus 2.5, 48% solids) 3. Flow improver / 0.8 wt .-% suspension of amorphous SiO 2 and improvers Water (50%) for the casting surface 4. Riesel sparkle 0.5% by weight of amorphous SiO 2
- Mixing unit Mixer Type: blade mixer Rotation speed: 160 U / min Mixing time: 1h
- the required heat energy was completely introduced by the resulting friction energy.
- the mixing time could be significantly reduced by the use of another mixing unit or external heat source or vacuum.
- the agglomerates were separated using a sieve with a mesh size of 1 mm.
- Example 1 A comparative measurement of the flowability of the molding sand produced in Example 1 with various other core and form sands is shown in Table 1: Comparative measurement with a pourability tester from the company Karg Industrietechnik: each 350g molding sand, spout ⁇ 15mm Table 1 molding sand Through amount Throughput time Quartz sand H32 (without binder) 350g 3.5s Croning (H32) 350g 3,3s Water glass-coated, dry H32 according to Example 1 350g 3,3s Cold box (H32) 8.2 g canceled after 5s AWB sand (H32) 6.1 g canceled after 5s Hot box (H32) 4.8g canceled after 5s furan 2.3g canceled after 5s As can be seen from the table, the core or foundry sand produced according to Example 1 has as good flowability as one produced by croning and is superior to the other conventional core sand.
- Tool parameters Core: Bending bar (2pcs) (Dimensions: 22.5mm x 22.5mm x 185mm) Mold temperature: 80 ° C Introduction of molding sand: pour Temperature water vapor-air mixture: > 105 ° C Pressure of the water vapor-air mixture: 1 bar Amount of water in the vapor-air mixture: 13ml duration: 30s
- Hot air temperature 160 ° C gassing pressure: 1 bar duration: 30s Average core weight: 137g
- the determination of the flowability was carried out at a sample amount of 350 g in a measuring funnel with an inner diameter at its upper, wide edge of 90 mm and funnel height of 95 mm in total and 32 mm in length and 15 mm in inner diameter of the outflow tube at room temperature of about 20 ° C measured.
- the water glass-coated molding material still has a water content or moisture content (based on the molding material weight) of 0.38% after the production process.
- the circulating core sand (thermally and mechanically loaded) only has a moisture content of 0.18%.
- test cores (test bars) were prepared from both molding material mixtures and the flexural strength was measured.
- the water glass-coated molding material of the present invention had an average bending strength of 481N / cm 2 , while the peripheral core sand was not capable of bonding and no cores could be produced therefrom.
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Abstract
Description
Die Erfindung betrifft einen Kern- oder Formsand zur Herstellung von Kernen und Gießformen, zum Vergießen von Metallschmelzen, wobei dieser einen Formgrundstoff (z.B. Quarzsand, Chromerzsand, Zirkonsand, Olivinsand, synthetische Sande) umfasst, der Wasserglas enthält und wobei der Kern- oder Formsand einen Wassergehalt im Bereich von ≥ etwa 0,25 Gew.-% bis etwa 0,9 Gew.-%, bezogen auf das Gesamtgewicht des Kern- und Formsands, hat. Des Weiteren betrifft die Erfindung ein Verfahren zur Herstellung eines solchen Kern- oder Formsands sowie ein Verfahren zum Herstellen eines Kerns oder einer Gießform mit diesem Kern- oder Formsand sowie dessen Verwendung.The invention relates to a core or molding sand for the production of cores and casting molds, for casting molten metal, which comprises a molding base material (eg quartz sand, chrome ore sand, zircon sand, olivine sand, synthetic sands) containing water glass and wherein the core or molding sand a Water content in the range of ≥ about 0.25 wt .-% to about 0.9 wt .-%, based on the total weight of the core and molding sand has. Furthermore, the invention relates to a method for producing such a core or foundry sand and a method for producing a core or a casting mold with this core or molding sand and its use.
Kern- oder Formsande für die Herstellung von Kernen oder anderen Gießformen, sind bekannt. Üblicherweise werden diese zunächst in die gewünschte Form gebracht, indem ein die Gießform abbildendes Werkzeug, wie ein Kernwerkzeug, mit dem Kern- oder Formsand befüllt und sodann der Kern- oder Formsand verdichtet und ausgehärtet wird. Nach Öffnen des Werkzeugs kann das gewünschte Formteil, beispielsweise ein Gießkern, entnommen werden. Unter Verwendung dieses Gießkerns können dann Metallschmelzen, unter anderem Leichtmetallschmelzen aus Aluminium, in die gewünschte Form gegossen werden. Nachdem die Metallschmelze erstarrt ist, kann der Gießkern oder die Gießform bspw. mittels Rütteln entfernt werden. Durch das Rütteln zerfällt der vormals feste und stabile Gießkern-/form.Core or molding sands for the production of cores or other casting molds are known. Usually, these are first brought into the desired shape by a die-forming tool, such as a core tool, filled with the core or molding sand and then the core or molding sand is compacted and cured. After opening the tool, the desired molding, such as a casting core, can be removed. Using this casting core, metal melts, including aluminum alloy melts, can then be poured into the desired shape. After the molten metal has solidified, the casting core or the casting mold can be removed, for example by means of shaking. By shaking the previously solid and stable Gießkern- / form decays.
Ein bekanntes Verfahren zur Herstellung von Kern- oder Formsand wird nach seinem Erfinder auch "Croning-Verfahren" genannt. Dabei wird als Formgrundstoff ein feinkörniger Quarzsand verwendet, bei dem jedes Sandkorn mit einer thermoplastischen Phenolharzschicht umhüllt ist. Die Phenolharze sind vor dem Erhitzen in unausgehärtetem Zustand bei Raumtemperatur fest. Wird der Kern- oder Formsand nunmehr in einen ein Formteil bildenden Hohlraum, wie ein die Gießform abbildendes Werkzeug, beispielsweise ein Kernwerkzeug, eingebracht und auf 250°C bis 300°C erwärmt, schmilzt der Binderfilm und es bilden sich durch Polykondensation Binderbrücken, die nach Abschluss der Polykondensationsreaktion fest sind und duroplastische Eigenschaften aufweisen. Der fertige Kern bzw. die fertige Form kann dem Werkzeug entnommen werden.A known process for the production of core or foundry sand is also called "croning process" according to its inventor. In this case, a fine-grained quartz sand is used as the molding material, in which each sand grain is coated with a thermoplastic phenolic resin layer. The phenolic resins are solid at room temperature before heating in the uncured state. If the core or foundry sand is now introduced into a molding cavity, such as a die-forming tool, such as a core tool, and heated to 250 ° C. to 300 ° C., the binder film melts and binder bridges are formed by polycondensation Conclusion of the polycondensation reaction are solid and have thermosetting properties. The finished core or the finished shape can be removed from the tool.
Der beim Croning-Verfahren verwendete Kern- oder Formsand hat den Vorteil gegenüber den anderen gängigen Kern-/Formherstellungsverfahren (z.B. Cold-Box, Hot-Box, Furanharz, Wasserglas-CO2 Verfahren), dass die Aushärtungsreaktion im Gegensatz zu den vorher genannten Verfahren nicht direkt nach dem Mischen, sondern erst nach erneuter Wärmezufuhr (250°C-300°C) beginnt. Die Lagerfähigkeit des fertig gemischten Kern- oder Formsands ist bei sachgemäßer Lagerung nahezu unbegrenzt. Bei der Verarbeitung zeigt der Kern- oder Formsand eine gute Fließfähigkeit, eine gute Abbildungsgenauigkeit, hohe Maßgenauigkeit, hohe Kantenschärfe und hohe Oberflächengüte. Nachteilig am Croning-Verfahren ist es jedoch, dass die Werkzeugtemperatur zur Herstellung der Kerne oder der Formteile aus dem Kern- oder Formsand außerordentlich hoch gewählt werden muss, was einen hohen Energiebedarf verursacht. Beim anschließenden Gießen mit einer Metallschmelze bei etwa 700°C-1700°C unter Verwendung von Kernen bzw. Formteilen, die mit dem Croning-Verfahren hergestellt wurden, verbrennt das Phenolharz, unter Freisetzung von gesundheitsschädlichen und umweltschädlichen Emissionen (z.B. mono- und polycyclischen Aromaten). Auch die Entsorgung der verwendeten Kern- bzw. Formteile nach dem Gießen stellt ein Umweltproblem dar, da diese nur mit hohem finanziellem Aufwand deponiert (Sondermülldeponie) werden können. Auch eine mögliche thermische Regenerierung ist mit extrem hohen Kosten und Umweltbelastungen verbunden.The core or molding sand used in the croning process has the advantage over other common core / mold making processes (eg cold box, hot box, furan resin, water glass CO 2 process) that the curing reaction is in contrast to the previously mentioned processes not directly after mixing, but only after renewed heat supply (250 ° C-300 ° C) begins. The shelf life of the ready-mixed core or foundry sand is virtually unlimited when properly stored. During processing, the core or molding sand exhibits good flowability, good image accuracy, high dimensional accuracy, high edge sharpness and high surface quality. However, a disadvantage of the croning process is that the tool temperature for producing the cores or the moldings from the core or molding sand must be selected to be extremely high, which causes a high energy requirement. In the subsequent casting with a molten metal at about 700 ° C-1700 ° C using cores produced by the croning process, the phenolic resin burns to release Harmful and polluting emissions (eg mono- and polycyclic aromatics). The disposal of the used core or molded parts after casting is an environmental problem, since they can be deposited only with high financial cost (hazardous waste landfill). Even a possible thermal regeneration is associated with extremely high costs and environmental pollution.
Zur Vermeidung der Umweltprobleme ist es außerdem bekannt, einen Formgrundstoff mit einem anorganischen, bspw. Wasserglas-basiertem Binder, zu verwenden. Dabei wird der Formgrundstoff mit einer wässrigen Lösung von Wasserglas gemischt und unmittelbar anschießend in ein Formwerkzeug eingeschossen. Zur Verfestigung des Kern- oder Formsands zu einem Formteil kann Wärme zugeführt werden, um durch Dehydratation den Kern- oder Formsand zu verfestigen (physikalische Härtung).In order to avoid the environmental problems, it is also known to use a molding material with an inorganic, for example. Water glass-based binder. In this case, the molding material is mixed with an aqueous solution of water glass and injected immediately anschießend in a mold. For solidification of the core or molding sand to a molding heat can be supplied to solidify by dehydration, the core or molding sand (physical hardening).
Bei einem anderen Verfahren wird der Kern- oder Formsand mit CO2 begast werden, um das Formteil chemisch zu härten.In another method, the core or molding sand will be gassed with CO 2 to chemically cure the molding.
So ist bspw. aus
Auch aus
Ein in diesen Verfahren verwendbares Bindemittelsystem auf Wasserglasbasis ist in
Außerdem ist aus
Allen herkömmlichen Verfahren unter Verwendung eines anorganischen Bindemittels ist somit gemeinsam, dass eine wässrige Alkalisilikatlösung mit einem Formgrundstoff gemischt wird und sodann dieses feuchte Gemisch unmittelbar in ein Formwerkzeug eingebracht wird. Nachteilig an diesen Verfahren ist es, dass das nach dem Mischen des Formgrundstoffs und der wässrigen Alkalisilikatlösung erhaltene Gemisch nicht lagerstabil bzw. nur bedingt lagerfähig ist, wie in einem geschlossenen Formstoffbehälter. Das bedeutet, dass die Mischung jeweils unmittelbar vor der Herstellung des Formteils hergestellt und sodann unmittelbar verwendet werden muss. Außerdem ist es nachteilig, dass der Kern- oder Formsand aus Formgrundstoff und einer wässrigen Alkalisilikatlösung nur bedingt rieselfähig ist und daher zusätzliche Maßnahmen ergriffen werden müssen, um sicherzustellen, dass der Kern- oder Formsand alle Hohlräume eines Formwerkzeugs ausfüllt, wie durch Anlegen von Unterdruck oder Rütteln des Formwerkzeugs. Auch der in
Der vorliegenden Erfindung liegt daher die Aufgabe zu Grunde, einen Kern- oder Formsand zur Verfügung zu stellen, der die Nachteile der herkömmlichen Kern- oder Formsande überwindet und insbesondere einen Kern- oder Formsand zur Verfügung zu stellen, der lagerstabil ist und unmittelbar, ohne weitere Schritte, zur Herstellung eines Formteils verwendet werden kann, ohne dass Gesundheits- oder Umweltrisiken mit seiner Benutzung verbunden sind. Des Weiteren soll der Kern- oder Formsand ein Einfüllen in ein Formwerkzeug einfach und sicher ermöglichen.The present invention is therefore based on the object to provide a core or molding sand available, which overcomes the disadvantages of conventional core or molding sand and in particular to provide a core or molding sand available, which is storage stable and immediately, without further Steps can be used to manufacture a molded article without health or environmental risks associated with its use. Furthermore, the core or molding sand should allow easy and safe filling into a mold.
Zur Lösung der Aufgabe wird ein Kern- oder Formsand für Kerne und Gießformen zum Vergießen von Metallschmelzen bereitgestellt, der einen Formgrundstoff umfasst, der mit Wasserglas beschichtet oder vermischt ist und einen Wassergehalt im Bereich von ≥ etwa 0,25 Gew.-% bis etwa 0,9 Gew.-%, bezogen auf das Gesamtgewicht des Kern- und Formsands, hat. Der Wassergehalt wird so verstanden, dass der obere und untere Wert des/der Bereichs(e) eingeschlossen sind. Außerdem wird ein Verfahren zur Herstellung eines erfindungsgemäßen Kern- oder Formsands bereitgestellt sowie ein Verfahren zum Herstellen eines Kerns und einer Gießform zum Vergießen von Metallschmelzen unter Verwendung des erfindungsgemäßen Kern- oder Formsands.To achieve the object, there is provided a core or molding sand for cores and casting molds for casting molten metal comprising a molding base material coated or mixed with water glass and having a water content in the range of ≥ about 0.25 wt% to about 0 , 9 wt .-%, based on the total weight of the core and molding sand has. The water content is understood to include the upper and lower values of the region (s). In addition, a method for producing a core or foundry sand according to the invention is provided and a method for producing a core and a casting mold for casting molten metal using the core or foundry sand according to the invention.
Das erfindungsgemäß verwendetet Wasserglas hat bevorzugt eine dynamische Viskosität von ≥ 102 Pa*s, bevorzugter ≥ 102,5 Pa*s, insbesondere von ≥ 103 Pa*s. Wasserglas mit einer dynamischen Viskosität von ≥ 102 Pa*s ist fest. Das bedeutet, dass der erfindungsgemäße Kern- oder Formsand insbesondere mit festem Wasserglas beschichtet oder vermischt ist.The water glass used according to the invention preferably has a dynamic viscosity of ≥ 10 2 Pa * s, more preferably 2,5 10 2.5 Pa * s, in particular of ≥ 10 3 Pa * s. Water glass with a dynamic viscosity of ≥ 10 2 Pa * s is solid. This means that the core or foundry sand according to the invention is coated or mixed in particular with solid water glass.
Außerdem hat der erfindungsgemäße Kern- und Formsand einen Wassergehalt im Bereich von ≥ etwa 0,25 Gew.-% bis etwa 0,9 Gew.-%, bezogen auf das Gesamtgewicht des Kern- und Formsands, bevorzugt von etwa ≥ etwa 0,3 Gew.-% bis etwa 0,9 Gew.-%, insbesondere von ≥ etwa 0,3 Gew.-% bis etwa 0,9 Gew.-%, bezogen auf das Gesamtgewicht des Kern- und Formsands. Wenn der Wassergehalt des Kern- und Formsands unter etwa 0,25 Gew.-%, bezogen auf das Gesamtgewicht des Kern- und Formsands liegt, dann wird kein Kern- und Formsand erhalten, der unmittelbar eingesetzt werden kann, insbesondere kein Kern- und Formsand, der in dem nachstehend beschriebenen erfindungsgemäßen Verfahren zum Herstellen eines Kerns und einer Gießform verwendbar wäre. Wenn der Wassergehalt über etwa 0,9 Gew.-% liegt, dann wird kein lagerstabiler Kern- oder Formsand erhalten. Der Wassergehalt wird nach dem VDG Merkblatt "
Der Begriff "beschichtet", wie er im Sinne der vorliegenden Erfindung verwendet wird, bedeutet, dass die einzelnen Partikel des Formgrundstoffs im Wesentlichen gleichmäßig von einer Wasserglasbeschichtung überzogen sind. Jedoch ist der Begriff nicht so zu verstehen, dass jeder einzelne Partikel des Formgrundstoffs getrennt voneinander mit einer Wasserglasbeschichtung überzogen sein muss, sondern umfasst auch Ausführungsformen, bei denen Partikel nur teilweise überzogen sind oder auch mehrere Partikel gemeinsam von einer Wasserglasbeschichtung umhüllt sind.The term "coated" as used in the context of the present invention means that the individual particles of the molding material are substantially uniformly coated by a waterglass coating. However, the term is not to be understood as meaning that each individual particle of the molding material must be coated separately with a waterglass coating, but also includes embodiments in which particles are only partially coated or several particles are coated together by a waterglass coating.
Der Begriff "vermischt", wie er im Sinne der vorliegenden Erfindung verwendet wird, bedeutet, dass das Wasserglas fest mit dem Formgrundstoff vermengt (homogenisiert) wird.The term "mixed", as used in the context of the present invention, means that the water glass is firmly mixed (homogenized) with the molding base material.
Der erfindungsgemäße Kern- oder Formsand zeichnet sich dadurch aus, dass er trocken und rieselfähig ist.The core or molding sand according to the invention is characterized in that it is dry and free-flowing.
Die Bestimmung der Rieselfähigkeit erfolgt beispielsweise mit Messtrichtern oder speziellen Rieselfähigkeitsprüfgeräten, wie von der Firma Karg Industrietechnik, wobei die Rieselzeit bei vorgegebener Masse oder vorgegebenem Volumen als Vergleichs-Indikator gemessen und in Sekunden angegeben wird.The determination of the flowability is carried out, for example, with measuring funnels or special pourability testing equipment, such as from the company Karg Industrietechnik, wherein the trickle time is measured at a given mass or given volume as a comparison indicator and specified in seconds.
Beispielsweise hat der erfindungsgemäße Kern- und Formsand bevorzugt eine Rieselfähigkeit von ≤ etwa 4 s, bevorzugter von ≤ etwa 3,5 s, gemessen bei einer Probenmenge von 350g in einem Messtrichter mit einem Innendurchmesser an dessen oberen, weiten Rand von 90 mm und einer Trichterhöhe von insgesamt 95 mm und einer Länge 32 mm und einem Innendurchmesser des Ausflussrohres von 15 mm bei Raumtemperatur von etwa 20 °C.For example, the core and molding sand of the present invention preferably has a flowability of ≤ about 4 seconds, more preferably ≤ about 3.5 seconds, measured at a sample amount of 350 g in a measuring funnel having an inner diameter at its upper, wide edge of 90 mm and a funnel height of a total of 95 mm and a length of 32 mm and an inner diameter of the spout of 15 mm at room temperature of about 20 ° C.
Bevorzugt umfasst das Wasserglas, mit dem der Formgrundstoff beschichtet oder vermischt ist, zusätzliche Additive, ausgewählt aus der Gruppe bestehend aus Haftvermittler, Fließverbesserer, Verbesserungsmittel für die Gussoberfläche und Trennmittel. Das Additiv ist bevorzugt ausgewählt aus der Gruppe, bestehend aus Natronlauge, amorphem SiO2, Graphit, Silikonölemulsion, Stearaten, diversen Ölen, Tensiden, Aluminiumoxiden, Eisenoxiden, Talkum, Bornitriden, Magnesiumoxid und diversen Metalloxiden.The water glass with which the molding base material is coated or mixed preferably comprises additional additives selected from the group consisting of adhesion promoters, flow improvers, casting surface improvers and release agents. The additive is preferably selected from the group consisting of sodium hydroxide solution, amorphous SiO 2 , graphite, silicone oil emulsion, stearates, various oils, surfactants, aluminum oxides, iron oxides, talc, boron nitrides, magnesium oxide and various metal oxides.
Bevorzugt ist der Haftvermittler ausgewählt aus Natronlauge, hygroskopische Basen und/oder Tensiden. Als Fließverbesserer werden bevorzugt Additive, ausgewählt aus der Gruppe bestehend aus amorphem SiO2, Graphit, Silikonöl, Silikonölemulsion, Stearaten, diversen Ölen und Tensiden verwendet. Als Verbesserungsmittel für die Gussoberfläche werden bevorzugt Additive, ausgewählt aus der Gruppe bestehend aus amorphen SiO2, Graphit, Aluminiumoxiden, Eisenoxiden, Talkum, Bornitriden, Magnesiumoxid und diversen Metalloxiden verwendet. Als Trennmittel werden bevorzugt Additive, ausgewählt aus der Gruppe bestehend aus Silikonöl, Silikonölemulsion, Aluminiumoxiden, Eisenoxiden, Talkum, Graphit und Bornitrid verwendet. Als Trocknungsmittel und/oder Rieselhilfe wird bevorzugt trockenes, amorphes SiO2 verwendet.The adhesion promoter is preferably selected from sodium hydroxide solution, hygroscopic bases and / or surfactants. The flow improvers used are preferably additives selected from the group consisting of amorphous SiO 2 , graphite, silicone oil, silicone oil emulsion, stearates, various oils and surfactants. As the improving agent for the casting surface, there are preferably used additives selected from the group consisting of amorphous SiO 2 , graphite, aluminum oxides, iron oxides, talc, boron nitrides, magnesium oxide and various metal oxides. The release agents used are preferably additives selected from the group consisting of silicone oil, silicone oil emulsion, aluminum oxides, iron oxides, talc, graphite and boron nitride. The drying agent and / or flow aid used is preferably dry, amorphous SiO 2 .
Als Formgrundstoff wird bevorzugt ein feuerfester mineralischer oder synthetischer Sand, insbesondere Quarzsand, Zirkonsand, Chromerzsand, nahezu kugelförmiger Sand, Olivinsand oder Gemische davon verwendet. Der Formgrundstoff hat bevorzugt eine mittlere Korngröße von etwa 0,08 mm bis 0,6 mm, insbesondere von 0,08 mm bis 0,5 mm.The molding material used is preferably a refractory mineral or synthetic sand, in particular quartz sand, zircon sand, chrome ore sand, almost spherical sand, olivine sand or mixtures thereof. The molding material preferably has a mean particle size of about 0.08 mm to 0.6 mm, in particular from 0.08 mm to 0.5 mm.
Des Weiteren können dem beschichteten erfindungsgemäßen Kern- oder Formsand weitere Hilfsstoffe zugesetzt werden, wie Rieselhilfen, Trocknungsmittel, Fließverbesserer, Verbesserungsmittel für die Gussoberfläche und/oder Trennmittel. Die weiteren Hilfsstoffe sind bevorzugt ausgewählt aus der Gruppe bestehend aus trockenem amorphen SiO2, Aluminiumoxiden, Eisenoxiden, Talkum, Graphit und Bornitriden. Die Eigenschaften der weiteren Hilfsstoffe sind wie vorstehend in Bezug auf deren Zugabe zu der Wasserglasbeschichtung beschrieben.Furthermore, further adjuvants can be added to the coated core or foundry sand according to the invention, such as flow aids, drying agents, flow improvers, improvers for the casting surface and / or release agents. The other auxiliaries are preferably selected from the group consisting of dry amorphous SiO 2 , aluminum oxides, iron oxides, talc, graphite and boron nitrides. The properties of the other adjuvants are as described above with respect to their addition to the waterglass coating.
Bevorzugt wird eine Gesamtmenge an Additiven (ohne Wasserglas) von bis zu 4 Gew.-%, insbesondere bis zu 3 Gew.-%, bezogen auf das Gesamtgewicht des Kern- oder Formsands zugegeben. Insbesondere bevorzugt umfasst der erfindungsgemäße Formsand keine organischen Additive oder Zusatzstoffe.Preferably, a total amount of additives (without water glass) of up to 4 wt .-%, in particular up to 3 wt .-%, based on the total weight of the core or foundry sand added. In particular, the molding sand according to the invention preferably does not comprise any organic additives or additives.
Der erfindungsgemäße Kern- oder Formsand wird bevorzugt in einem Verfahren hergestellt, das die folgenden Schritte umfasst: a) ein erfindungsgemäßer Formgrundstoff wird bereitgestellt, b) eine wässrige Lösung von Wasserglas und/oder trockenes Wasserglaspulver wird zugegeben und c) der Kern- oder Formsand wird gemischt, getrocknet und kornvereinzelt.The core or foundry sand according to the invention is preferably produced in a process comprising the following steps: a) a molding base material according to the invention is provided, b) an aqueous solution of waterglass and / or dry waterglass powder is added and c) the core or molding sand mixed, dried and singed.
Bevorzugt wird dazu zunächst in Schritt a) ein Mischer mit dem Formgrundstoff befüllt, der die Homogenisierung des Kern- oder Formsands mit den Binderkomponenten und gegebenenfalls den Additiven gewährleistet. Als Mischer werden bevorzugt Flügelmischer, Schwingmischer, Intensivmischer, Wirbelmischer oder Vertikalkollergang verwendet.For this purpose, in step a), a mixer is preferably first filled with the basic molding material, which ensures the homogenization of the core or molding sand with the binder components and optionally the additives. As mixers, preference is given to using wing mixers, oscillating mixers, intensive mixers, vortex mixers or vertical rolling gears.
In Schritt b) kann sodann eine wässrige Lösung von Wasserglas und/oder trockenes/festes Wasserglas und gegebenenfalls weitere Additive zugegeben. Wenn eine wässrige Lösung verwendet wird, hat diese bevorzugt eine dynamische Viskosität von bis zu 102 Pa*s. Damit umfasst der Begriff "wässrige Lösung" sowohl dünnflüssige, dickflüssige als auch pastöse Wassergläser. Wenn ein trockenes/festes Wasserglas zugegeben wird, so hat dieses bevorzugt eine dynamische Viskosität von mehr als 102 Pa*s. Es ist auch möglich, ein Gemisch aus verschiedenen Wassergläsern und/oder ein Gemisch aus einer wässrigen Lösung von Wasserglas und trockenem/festen Wasserglas zuzugeben. Bevorzugt ist das verwendete Wasserglas eine Alkalisilikatlösung der allgemeinen Zusammensetzung xSiO2 ˙ yM2O ˙ nH2O, wobei M ausgewählt ist aus Li+, K+ oder Na+ und x : y bevorzugt etwa 1 : 1 bis 4 : 1, insbesondere etwa 2 : 1 bis 3,5 : 1, beträgt (wobei das Verhältnis x : y auch als Modul des Wasserglases, d. h. das Mengenverhältnis SiO2 : M2O ist). Der Index n bestimmt dann die Menge an H2O in der Lösung. Des Weiteren wird bevorzugt eine wässrige Lösung an Alkalisilikat verwendet, die einen Feststoffgehalt von nicht mehr als etwa 60 Gew.-%, bezogen auf die gesamte Lösung, hat.In step b), an aqueous solution of water glass and / or dry / solid water glass and optionally further additives may then be added. If an aqueous solution is used, it preferably has a dynamic viscosity of up to 10 2 Pa * s. Thus, the term "aqueous solution" includes both liquid, viscous and pasty water glasses. When a dry / solid water glass is added, it preferably has a dynamic viscosity of more than 10 2 Pa * s. It is also possible to add a mixture of different water glasses and / or a mixture of an aqueous solution of water glass and dry / solid water glass. Preferably, the water glass used is an alkali silicate solution of the general composition xSiO 2 ˙ yM 2 O ˙ nH 2 O, wherein M is selected from Li + , K + or Na + and x: y preferably about 1: 1 to 4: 1, in particular about 2: 1 to 3.5: 1 (where the ratio x: y is also the modulus of the water glass, ie the SiO 2 : M 2 O ratio). The index n then determines the amount of H 2 O in the solution. Further, an aqueous solution of alkali silicate having a solid content of not more than about 60% by weight based on the entire solution is preferably used.
Bevorzugt werden etwa 0,5 bis etwa 8 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs des Wasserglases, zugegeben. Zusätzlich kann bevorzugt ein Haftvermittler in einer Menge von bis zu etwa 0,5 Gew.-%, vorzugsweise etwa 0,1 bis etwa 0,2 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs, zugegeben werden. Bevorzugt ist der Haftvermittler eine wässrige Lösung von Natronlauge, insbesondere eine etwa 10 bis etwa 50%ige, besonders bevorzugt eine 30%ige Natronlauge. Insbesondere bevorzugt wird der Haftvermittler dem Formgrundstoff in Schritt b) vor der Zugabe der wässrigen Lösung von Wasserglas zugegeben.Preferably, about 0.5 to about 8 wt .-%, based on the weight of the molding material of the water glass added. In addition, an adhesion promoter may preferably be added in an amount of up to about 0.5% by weight, preferably about 0.1 to about 0.2% by weight, based on the weight of the masterbatch. The adhesion promoter is preferably an aqueous solution of sodium hydroxide solution, in particular about 10 to about 50%, particularly preferably a 30% sodium hydroxide solution. Particularly preferably, the adhesion promoter is added to the molding base material in step b) before the addition of the aqueous solution of water glass.
Bevorzugt wird anschließend an die Zugabe des Haftvermittlers die wässrige Lösung von Wasserglas zugegeben.Preferably, the aqueous solution of water glass is then added to the addition of the adhesion promoter.
Sodann wird bevorzugt ein Fließverbesserer oder Verbesserungsmittel für die Gussoberfläche bevorzugt in Mengen bis zu etwa 3 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs, zugegeben. Insbesondere bevorzugt wird zunächst eine wässrige Suspension aus amorphem SiO2, bevorzugt in einer Menge bis zu etwa 3 Gew.-%, insbesondere etwa 0,6 bis etwa 1,0 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs, und sodann bevorzugt eine wässrige Suspension aus amorphem SiO2 und Graphit, bevorzugt in einer Menge von bis zu etwa 3 Gew.-%, insbesondere etwa 0,6 bis etwa 1,0 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs, dazugegeben. Die wässrige Suspension ist bevorzugt etwa 10 bis etwa 80%ig, insbesondere etwa 30 bis etwa 60%ig. Zum Abschluss wird bevorzugt in Schritt b) ein Fließverbesserer und/ oder Trennmittel in einer Menge von bis zu etwa 1 Gew.-%, insbesondere bis etwa 0,8 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs, zugegeben, insbesondere bevorzugt ein Silikonöl und/ oder eine Silikonölemulsion.Then, preferably, a flow improver or casting surface improver is preferably added in amounts up to about 3% by weight, based on the weight of the masterbatch. Particularly preferred is first an aqueous suspension of amorphous SiO 2 , preferably in an amount up to about 3 wt .-%, in particular about 0.6 to about 1.0 wt .-%, based on the weight of the mold base material, and then preferred an aqueous suspension of amorphous SiO 2 and graphite, preferably in an amount of up to about 3 wt .-%, in particular about 0.6 to about 1.0 wt .-%, based on the weight of the molding base material, added thereto. The aqueous suspension is preferably about 10 to about 80%, in particular about 30 to about 60% pure. Finally, in step b), a flow improver and / or release agent is preferably added in an amount of up to about 1% by weight, in particular up to about 0.8% by weight, based on the weight of the molding base material Silicone oil and / or a silicone oil emulsion.
Außerdem ist es auch möglich, auf die Zugabe aller Additive zu verzichten, so dass die Mischung nur aus dem Formgrundstoff und dem Wasserglas besteht.In addition, it is also possible to dispense with the addition of all additives, so that the mixture consists only of the molding material and the water glass.
In einer besonders bevorzugten Ausführungsform wird Schritt b) durchgeführt, indem zunächst ein Haftvermittler, bevorzugt Natronlauge, sodann das Bindemittel, nämlich die gegebenenfalls wässrige Lösung von Wasserglas, anschließend ein Fließverbesserer und/ oder Verbesserungsmittel für die Gussoberfläche, insbesondere bevorzugt eine wässrige Suspension aus amorphem SiO2 und sodann amorphes SiO2 und Graphit zugegeben wird, gefolgt von der Zugabe eines Fließverbesserers und/oder Trennmittels, insbesondere von Silikonöl oder einer Silikonölemulsion. Insbesondere bevorzugt wird nach der Zugabe jeder einzelnen Komponente das Gemisch mittels des Mischers homogenisiert. In einer alternativen Ausführungsform wird nach Zugabe aller Komponenten das Gemisch mittels des Mischers homogenisiert.In a particularly preferred embodiment, step b) is carried out by first an adhesion promoter, preferably sodium hydroxide solution, then the binder, namely the optionally aqueous solution of waterglass, then a flow improver and / or improver for the casting surface, particularly preferably an aqueous suspension of amorphous SiO 2, and then amorphous SiO 2 and graphite are added, followed by the addition of a flow improver and / or release agent, particularly silicone oil or a silicone oil emulsion. In particular, after the addition of each individual component, the mixture is homogenized by means of the mixer. In an alternative embodiment, after addition of all components, the mixture is homogenized by means of the mixer.
In einer anderen bevorzugten Ausführungsform kann in Schritt b) bereits trockenes/festes Wasserglas oder ein Gemisch aus wässrigem und trockenem/festen Wasserglas zugegeben werden, wodurch es im Falle der Zugabe von trockenem/festem Wasserglas nicht erforderlich ist, das Gemisch zu trocknen. In dieser Ausführungsform dient das Mischen der Herstellung eines möglichst gleichmäßigen Gemisches.In another preferred embodiment, dry / solid water glass or a mixture of aqueous and dry / solid water glass may already be added in step b), whereby in the case of addition of dry / solid water glass it is not necessary to dry the mixture. In this embodiment, the mixing serves to produce as uniform a mixture as possible.
In Schritt c) wird sodann der Kern- oder Formsand getrocknet. Zum Trocknen wird bevorzugt die durch den Mischer in das Gemisch eingetragene Reibungsenergie verwendet. Hierzu wird insbesondere bevorzugt, ein Flügelmischer verwendet, der eine Drehzahl von 160 U/min hat und es wird bevorzugt 1h lang gemischt wird. Durch die Erwärmung unter ständiger Verwirbelung wird dem Gemisch Wasser entzogen. Erfindungsgemäß wird der Wassergehalt des Wasserglases, mit dem der Formgrundstoff durch das Mischen und die Dehydratation beschichtet oder gemischt wird, auf einen Gehalt im Bereich von ≥ etwa 0,25 Gew.-% bis etwa 0,9 Gew.-% eingestellt. Dadurch wird ein Kern- oder Formsand erhalten, der mit einer festen Beschichtung an Wasserglas versehen ist. Der Formgrundstoff, der nach dem erfindungsgemäßen Verfahren erhalten wird, ist somit mit Wasserglas beschichtet, wobei gleichzeitig ein rieselfähiger Kern- oder Formsand erhalten wird, der außerdem lagerstabil ist.In step c), the core or molding sand is then dried. For drying, the friction energy introduced into the mixture by the mixer is preferably used. For this purpose, it is particularly preferred to use a wing mixer which has a rotational speed of 160 rpm and it is preferably mixed for one hour. By heating under constant turbulence the mixture is deprived of water. According to the invention, the water content of the water glass with which the molding base material is coated or mixed by mixing and dehydration is adjusted to a content in the range of ≥ about 0.25 wt% to about 0.9 wt%. As a result, a core or molding sand is obtained, which is provided with a solid coating of water glass. The molding base material obtained by the process according to the invention is thus coated with waterglass, at the same time a free-flowing core or molding sand is obtained, which is also storage stable.
Das Trocknen kann mit jeder beliebigen Vorrichtung durchgeführt werden, solange sichergestellt ist, dass der Wassergehalt der Wasserglasbeschichtung des Formgrundstoffs eingehalten wird. Bevorzugt kann dazu auch eine externe Heizung, Heißluft, Strahlungsheizung, Vakuum, bzw. Unterdruck oder ein Heizmantel verwendet werden.The drying can be carried out with any device as long as it is ensured that the water content of the water glass coating of the molding base material is maintained. An external heating, hot air, radiant heating, vacuum, or negative pressure or a heating jacket can preferably also be used for this purpose.
Nach dem Mischen können dem Kern- oder Formsand weitere Hilfsstoffe zugegeben werden, wie Rieselhilfen, Trocknungsmittel, Fließverbesserer, Verbesserungsmittel für die Gussoberfläche oder Trennmittel. Bevorzugt wird von jedem Hilfsstoff eine Menge von bis zu etwa 2 Gew.-%, bezogen auf das Gewicht des Formgrundstoffs.After mixing, other adjuvants can be added to the core or molding sand, such as flow aids, desiccants, flow improvers, casting surface improvers, or release agents. Preferably, each adjuvant will contain an amount of up to about 2% by weight, based on the weight of the masterbatch.
Bevorzugt kann dem Formgrundstoff vor Schritt c) zusätzlich wenigstens ein weiteres Additiv, ausgewählt aus der Gruppe, bestehend aus Haftvermittler, Fließverbesserer, Verbesserungsmittel für die Gußoberfläche und Trennmittel zugegeben werden. Außerdem kann bevorzugt dem Kern- oder Formsand nach Schritt c) wenigstens ein weiterer Hilfsstoff, ausgewählt aus der Gruppe, bestehend aus Rieselhilfen, Trocknungsmittel, Fließverbesserer, Verbesserungsmittel für die Gußoberfläche und Trennmittel zugegeben werden.Preferably, at least one further additive selected from the group consisting of adhesion promoters, flow improvers, casting surface improvers and release agents may be added to the masterbatch before step c). In addition, at least one further adjuvant selected from the group consisting of flow aids, drying agents, flow improvers, casting surface improvers and release agents may preferably be added to the core or molding sand after step c).
Bevorzugt kann der so erhaltene Kern- oder Formsand sodann zur Abscheidung von Agglomeraten gesiebt werden.Preferably, the core or molding sand thus obtained can then be screened for the deposition of agglomerates.
Der so erhaltene erfindungsgemäße Kern- oder Formsand kann sodann direkt verwendet werden, um einen Kern oder ein Formteil herzustellen. Der erfindungsgemäße Kern- oder Formsand kann jedoch auch lose oder verpackt gelagert werden und ist wegen seiner Konsistenz nahezu unbegrenzt lagerfähig. Damit kann der erfindungsgemäße Kern- oder Formsand getrennt von einem Verfahren zur Herstellung des Formteils hergestellt und gelagert, verpackt oder transportiert werden, was für die Gießereien und die Hersteller von Kern und Formteilen eine erhebliche Arbeitserleichterung und Zeitersparnis bedeutet.The resulting core or foundry sand according to the invention can then be used directly to produce a core or a molded part. However, the core or foundry sand according to the invention can also be stored loose or packed and can be stored almost indefinitely because of its consistency. Thus, the core or foundry sand according to the invention can be prepared separately from a method for producing the molded part and stored, packaged or transported, which means a considerable work and time savings for the foundries and the manufacturer of core and moldings.
Insbesondere bevorzugt umfasst der erfindungsgemäße Kern- und Formsand keine organischen Additive oder Zusatzstoffe, so dass bei dessen Verwendung keine umweltschädlichen Stoffe entstehen.In particular, the core and foundry sand according to the invention preferably does not comprise any organic additives or additives, so that no environmentally harmful substances are formed when it is used.
Der erfindungsgemäße Kern- oder Formsand wird sodann vorteilhaft in einem Verfahren zum Herstellen einer Gießform bzw. eines Kerns oder Kernformlings zum Vergießen von Metallschmelzen eingesetzt. Dazu wird zunächst für die Kernherstellung a) ein erfindungsgemäßer Kern- oder Formsand bereitgestellt und b) ein Kernwerkzeug oder Werkzeug mit dem erfindungsgemäßen Kern- oder Formsand befüllt. Das Einfüllen kann z.B. durch Rieseln, Blasen und/oder Schießen mit einem Trägermedium z.B. Druckluft, Heißluft oder Wasserdampf durchgeführt werden. Dies kann mittels einer handelsüblichen Kernschießmaschine oder auch durch Saugförderung und anschließendem Blasen erfolgen. Bevorzugt wird sodann der Kern- oder Formsand im Kernwerkzeug verdichtet.The core or foundry sand according to the invention is then advantageously used in a method for producing a casting mold or a core or core molding for casting molten metal. For this purpose, a core or molding sand according to the invention is initially provided for the core production a) and b) a core tool or tool is filled with the core or molding sand according to the invention. The filling can eg be carried out by trickling, blowing and / or shooting with a carrier medium such as compressed air, hot air or steam. This can be done by means of a commercial core shooter or by suction and subsequent bubbles. Preferably, the core or molding sand is then compressed in the core tool.
Zum Aushärten und Verfestigen des Kern- oder Formsands zur Bildung des Kerns wird c) der Kern- oder Formsand im Werkzeug mit wenigstens einem Härtungsmittel, vorzugsweise Wasser, Wasserhaltigen Flüssigkeiten und/oder chemischen Härtungsmitteln, wie CO2, in Kontakt gebracht. Bevorzugt wird dazu Wasserdampf verwendet. Der Wasserdampf wird dazu bevorzugt in das Werkzeug eingebracht. Der Wasserdampf kann z.B. mittels einer Begasungsplatte über die Einschüsse und/oder durch den Dampfanschluss an die Werkzeugentlüftungen in den Formstoff eingebracht werden. Insbesondere bevorzugt wird ein Wasserdampf-Luftgemisch verwendet, das vorzugsweise eine Menge an Wasser bis etwa 6 Gew.-% bezogen auf den Formgrundstoff, insbesondere 3-4 Gew.-% enthält. Der Druck ist bevorzugt bis zu etwa 10bar, insbesondere etwa 0,5 bis etwa 1,5 bar.For hardening and solidifying the core or molding sand to form the core, c) the core or molding sand in the tool is brought into contact with at least one hardening agent, preferably water, water-containing liquids and / or chemical hardening agents such as CO 2 . Preferably, steam is used for this purpose. The water vapor is preferably introduced into the tool. The water vapor can be introduced into the molding material, for example, by means of a gassing plate via the injections and / or through the steam connection to the tool vents. Particularly preferred is a water vapor-air mixture is used, which preferably contains an amount of water to about 6 wt .-% based on the mold base, in particular 3-4 wt .-%. The pressure is preferably up to about 10 bar, in particular about 0.5 to about 1.5 bar.
Zur Herstellung einer Gießform bzw. eines Kerns oder Kernformlings wird somit der erfindungsgemäße Kern- oder Formsand in ein Kernwerkzeug bzw. Formwerkzeug gebracht, vorzugsweise durch Schießen oder Schütten, und anschließend vorzugsweise verdichtet. Die Verdichtung erfolgt vorzugsweise durch Rütteln und Pressen. Zum Aushärten und Verfestigen des Kern- oder Formsands zur Bildung des Kerns wird der Kern- oder Formsand im Werkzeug bevorzugt mit einer wässrigen Lösung oder Wasser in Kontakt gebracht. Bevorzugt wird dazu Wasserdampf verwendet. Das Inkontaktbringen mit Wasser, insbesondere Wasserdampf, kann bevorzugt während des Schritts b) beispielsweise im zeitlichen Zusammenhang mit dem Befüllen, insbesondere dem Schießen des Kern- oder Formsands, oder nach dessen Einfüllen in einem getrennten Schritt c) durchgeführt werden.To produce a casting mold or a core or core molding, the core or molding sand according to the invention is thus brought into a core tool or molding tool, preferably by firing or pouring, and then preferably compacted. The compaction is preferably carried out by shaking and pressing. For hardening and solidifying the core or molding sand to form the core, the core or molding sand in the tool is preferably brought into contact with an aqueous solution or water. Preferably, steam is used for this purpose. The contacting with water, in particular water vapor, can preferably be carried out during step b), for example, in a temporal relationship with the filling, in particular the firing of the core or foundry sand, or after its filling in a separate step c).
Durch das Inkontaktbringen mit Wasser wird die Wasserglasbeschichtung des erfindungsgemäßen Kern- oder Formsands angelöst und erweicht. Durch das Erweichen der Wasserglasbeschichtung bilden sich Binderbrücken zwischen den Partikeln des Kern- oder Formsands.By contacting with water, the waterglass coating of the core or molding sand according to the invention is dissolved and softened. By softening the waterglass coating, binder bridges form between the particles of the core or foundry sand.
Anschließend wird bevorzugt der Kern verfestigt, insbesondere, indem das Wasser entfernt wird oder auf chemischem Wege. Dies kann bevorzugt dadurch erreicht werden, dass im Anschluss Energie, in Form eines Wärmeträgermediums, wie in Form von heißer Luft oder eines Wasserdampf-Luftgemisch, das durch den Kern geleitet wird, in den Kern eingebracht wird. In einer weiteren Ausführungsform kann das Wasser entfernt werden, indem ein Unterdruck an das Werkzeug angelegt wird. Durch das Entfernen des Wassers verfestigt sich das Wasserglas und es wird ein stabiles, festes Formteil erhalten. Es handelt sich somit um einen im Wesentlichen physikalischen Vorgang, ohne dass zusätzliche chemische Reaktionen notwendig wären.Subsequently, preferably the core is solidified, in particular by removing the water or by chemical means. This can preferably be achieved by subsequently introducing energy into the core in the form of a heat transfer medium, such as in the form of hot air or a water vapor-air mixture which is passed through the core. In another embodiment, the water may be removed by applying a vacuum to the tool. By removing the water, the water glass solidifies and it is a stable, solid molding obtained. It is thus a substantially physical process without the need for additional chemical reactions.
In einer alternativen Ausführungsform kann jedoch als Härtungsmittel CO2 verwendet werden und die Verfestigung wird damit im Wesentlichen chemisch durchgeführt. In einer weiteren Ausführungsform können auch beide Verfahren zum Verfestigen entweder gleichzeitig oder auch nacheinander durchgeführt werden. Nach dem Aushärten oder Verfestigen (Trocknen) des Formteils kann das Werkzeug geöffnet und das fertige Fonnteil, bspw. ein Kern, entnommen werden.In an alternative embodiment, however, CO 2 can be used as the hardening agent and the solidification is thus carried out essentially chemically. In a further embodiment, both methods for solidification can be carried out either simultaneously or also successively. After hardening or solidifying (drying) of the molding, the tool can be opened and the finished Fonnteil, eg. A core removed.
In einer weiteren Ausführungsform kann der Kern innerhalb des Kernwerkzeugs nur vorverfestigt, beispielsweise vorgetrocknet werden, bis der Kern eine ausreichende Festigkeit aufweist, um aus dem Kernwerkzeug entnommen zu werden. Danach kann der vorverfestigte Kern außerhalb des Kernwerkzeugs weiter verfestigt werden, insbesondere kann der vorgetrocknete Kern beispielsweise in einer Mikrowelle, einem Ofen, oder einer Trockenkammer fertig getrocknet werden.In another embodiment, the core within the core tool may only be preconsolidated, for example pre-dried, until the core has sufficient strength to be removed from the core tool. Thereafter, the preconsolidated core may be further solidified outside the core tool, in particular, the predried core may be finish dried in, for example, a microwave, an oven, or a drying chamber.
In einer bevorzugten Ausführungsform wird das Werkzeug zur Bildung des Kerns- bzw. Formteils während aller Schritte b) bis c) auf eine Temperatur von Raumtemperatur oder etwa 20°C bis etwa 200°C, bevorzugter etwa 70°C bis etwa 160°C, insbesondere etwa 70 bis etwa 120°C erwärmt. Außerdem ist es möglich, das Inkontaktbringen des Formteils mit Wasser, bevorzugt mit Wasserdampf, in zeitlichem Zusammenhang mit dem Einfüllen des Kern- oder Formsands in den das Formteil abbildenden Hohlraum durchzuführen, wie bereits vorgehend beschrieben. Damit wird vorteilhaft sichergestellt, dass bei Verwendung von Wasserdampf kein flüssiges Wasser im Werkzeug gebildet wird bzw. am Werkzeug kondensiert. Außerdem kann dann unmittelbar nach Einfüllen und Inkontaktbringen des Kern- oder Formsands mit Wasser diesem das Wasser wiederum entzogen werden, beispielsweise indem das Werkzeug auf die genannten Temperaturen erwärmt ist. Außerdem kann das Wasser zusätzlich oder alternativ unter Verwendung von Heißluft und/oder Beaufschlagen mit warmem Trägergas und/oder durch Anlegen eines Unterdrucks/Vakuums entzogen werden. Die Dauer des Inkontaktbringens mit Wasser kann beispielsweise für etwa 5 min bis etwa 3 h durchgeführt werden.In a preferred embodiment, the tool for forming the core or molding during all steps b) to c) to a temperature of from room temperature or about 20 ° C to about 200 ° C, more preferably about 70 ° C to about 160 ° C, heated in particular about 70 to about 120 ° C. In addition, it is possible to carry out the contacting of the molding with water, preferably with water vapor, in temporal connection with the filling of the core or molding sand in the mold cavity imaging, as already described above. This advantageously ensures that when using steam no liquid water is formed in the tool or condenses on the tool. In addition, immediately after filling and contacting the core or molding sand with water, the water can then be withdrawn, for example, by the tool being heated to said temperatures. In addition, the water may additionally or alternatively be withdrawn using hot air and / or warm carrier gas and / or by applying a negative pressure / vacuum. The duration of contact with water may be carried out, for example, for about 5 minutes to about 3 hours.
Vorstehend wird das Verfahren bevorzugt mit einem Ablauf der Schritte a) bis c) beschrieben. Es ist jedoch auch eine andere Reihenfolge der Schritte möglich und im Sinne dieser Erfindung.In the above, the method is preferably described with a sequence of steps a) to c). However, another sequence of steps is possible and within the meaning of this invention.
Der erfindungsgemäße Kern oder die erfindungsgemäße Gießform hat bevorzugt eine Biegefestigkeit von wenigstens etwa 300 N/cm2, bevorzugter wenigstens etwa 400 N/cm2 und insbesondere wenigstens etwa 450 N/cm2. Die Biegefestigkeit des Kerns wird entsprechend dem VDG Merkblatt P 72 "Bindemittelprüfung, Prüfung von kalthärtenden, kunstharzgebundenen feuchten Formstoffen mit Härterzusatz" vom Oktober 1999 geprüft.The core or mold of the present invention preferably has a flexural strength of at least about 300 N / cm 2 , more preferably at least about 400 N / cm 2, and most preferably at least about 450 N / cm 2 . The flexural strength of the core is tested in accordance with the VDG leaflet P 72 "Binder Testing, Testing of Cold-curing, Resin-Bonded Wet Forming Materials with Hardening Additive" dated October 1999.
Ein solcher, erfindungsgemäße hergestellter Kern kann dann zur Herstellung einer Gießform zum Vergießen von Metallschmelzen eingesetzt werden.Such a manufactured core according to the invention can then be used to produce a casting mold for casting molten metal.
Das erfindungsgemäße Verfahren und der erfindungsgemäße Formsand haben den Vorteil, dass der erfindungsgemäße Formsand auf Grund seiner Rieselfähigkeit ein ähnliches Schießverhalten, wie der im vorstehend beschriebenen Croning-Verfahren verwendete Kern- oder Formsand hat und damit ohne zusätzliche Schritte zuverlässig in ein Form- bzw. Kernwerkzeug eingebracht werden kann. Im Gegensatz zum Croning-Verfahren kann das erfindungsgemäße Verfahren jedoch durch rein physikalische Schritte zur Verfestigung des Formteils durchgeführt werden, wobei keinerlei umweltschädigende Substanzen gebildet werden. Dies ist vorteilhaft, da beim Abgießen des flüssigen Metalls keine aufwändigen Absauganlagen in der Gießerei vorgehalten werden müssen und die Angestellten keinen gesundheitsgefährdenden Gasen wie Phenolverbindungen ausgesetzt sind. Das Recycling und die Entsorgung des verwendeten anorganischen Kern- oder Formsands sind problemlos möglich. Während des erfindungsgemäßen Verfahrens, im Gegensatz zum Croning-Verfahren, können zur Verfestigung deutlich niedrigere Temperaturen verwendet werden, was zu einer erheblichen Energieeinsparung führt. Außerdem hat sich als vorteilhaft herausgestellt, dass bei der Verwendung der anorganisch gebundenen Kerne im Kokillenguss Kondensationsprodukte in der Kokille deutlich vermindert werden. Damit ergibt sich ein geringerer Reinigungsaufwand der Kokille nach dem Abguss und dadurch eine höhere Kokillenverfügbarkeit, wodurch eine Produktivitätssteigerung erreicht werden kann. Mit dem erfindungsgemäßen Verfahren können Formteile hergestellt werden, die eine gute Abbildungsgenauigkeit und hohe Kantenschärfe haben.The inventive method and molding sand have the advantage that the molding sand according to the invention due to its flowability has a similar shooting behavior, such as the core or molding sand used in the croning process described above and thus reliably without additional steps in a mold or core tool can be introduced. In contrast to the croning process, however, the process of the invention can be carried out by purely physical steps for solidification of the molded part, wherein no environmentally harmful substances are formed become. This is advantageous because when pouring the liquid metal no elaborate extraction systems must be kept in the foundry and the employees are exposed to no hazardous gases such as phenolic compounds. The recycling and disposal of the used inorganic core or foundry sand are easily possible. During the process according to the invention, in contrast to the croning process, significantly lower temperatures can be used for solidification, which leads to a considerable energy saving. In addition, it has been found to be advantageous that when using the inorganically bonded cores in chill casting condensation products in the mold are significantly reduced. This results in a lower cleaning costs of the mold after casting and thus a higher mold availability, whereby an increase in productivity can be achieved. With the method according to the invention molded parts can be produced, which have a good imaging accuracy and high edge sharpness.
Des Weiteren betrifft die Erfindung ein Kernwerkzeug bzw. Formwerkzeug zur Herstellung eines Kernformlings bzw. einer Gießform. Das Kernwerkzeug ist entsprechend herkömmlichen Kernwerkzeugen ausgestattet, die zur Herstellung einer Gießform geeignet sind, wobei wenigstens einen Anschluss, der zum Einleiten eines Härtungsmittels, wie beispielsweise Wasserdampf oder einem chemischen Härtungsmittel geeignet ist, vorgesehen ist. Gegebenenfalls können weitere Öffnungen in dem Kernwerkzeug angebracht sein, aus welchen das Härtungsmittel, wie der Wasserdampf oder das chemische Härtungsmittel, wiederum entweichen kann. Insbesondere umfasst das Kernwerkzeug eine geeignete Form zur Herstellung des gewünschten Kernformlings bzw. Gießform sowie wenigstens einen Anschluss zum Einbringen bzw. Einschießen des Kern- und Formsand, sowie wenigstens einen Anschluss für das Einleiten eines Härtungsmittels, wie Wasserdampf oder ein chemisches Härtungsmittel. Die Anschlüsse können jedoch auch zusammen in einem Anschluss vorgesehen werden, d.h. ein Anschluss, der sowohl zum Einschießen des Kern- und Formsands als auch des Härtungsmittels, wie Wassers und/oder des chemischen Härtungsmittels geeignet ist. Der Anschluss kann auch eine Begasungsplatte, gleichzeitig die Einschüsse und/oder ein getrennter Dampfanschluss an den Werkzeugentlüftungen sein. Das Kernwerkzeug ist bevorzugt zweiteilig ausgebildet, um den Kernformling bzw. die Gießform nach der Herstellung einfach zu entnehmen.Furthermore, the invention relates to a core tool or molding tool for producing a core molding or a casting mold. The core tool is equipped in accordance with conventional core tools suitable for making a casting mold, wherein at least one port suitable for introducing a curing agent such as water vapor or a chemical curing agent is provided. Optionally, further openings may be provided in the core tool, from which the curing agent, such as the water vapor or chemical curing agent, may again escape. In particular, the core tool comprises a suitable mold for producing the desired core molding or mold and at least one connection for introducing or injecting the core and molding sand, and at least one connection for introducing a curing agent, such as water vapor or a chemical curing agent. However, the terminals may also be provided together in one terminal, i. a connector which is suitable both for injecting the core and molding sand and the curing agent, such as water and / or the chemical curing agent. The connection may also be a gassing plate, at the same time the injections and / or a separate steam connection to the tool vents. The core tool is preferably designed in two parts in order to simply remove the core blank or the casting mold after production.
Die Erfindung wird nunmehr anhand von Beispielen verdeutlicht.The invention will now be illustrated by way of examples.
Bindergattierung:
Die erforderliche Wärmeenergie wurde vollständig durch die entstehende Reibungsenergie eingebracht. Alternativ könnte die Mischzeit durch die Verwendung eines anderen Mischaggregats oder einer externen Wärmequelle, bzw. eines Unterdrucks erheblich reduziert werden.The required heat energy was completely introduced by the resulting friction energy. Alternatively, the mixing time could be significantly reduced by the use of another mixing unit or external heat source or vacuum.
Die Abscheidung der Agglomerate erfolgte mit Hilfe eines Siebes mit der Maschenweite von 1mm.The agglomerates were separated using a sieve with a mesh size of 1 mm.
Eine Vergleichsmessung der Rieselfähigkeit des in Beispiel 1 hergestellten Formsands mit verschiedene anderen Kern- und Formsanden ist in Tabelle 1 gezeigt:
Vergleichmessung mit einem Rieselfähigkeitsprüfgerät der Firma Karg Industrietechnik: je 350g Formsand, Auslauf Ø15mm
Comparative measurement with a pourability tester from the company Karg Industrietechnik: each 350g molding sand, spout Ø15mm
Werkzeugparameter:
Für die Versuche wurden die in Beispiel 1 angegeben sowie die folgenden weiteren Formstoffmischungen verwendet:
- Wasserglasumhüllter Formstoff
H32 + 0,1% Additiv A + 5,0% Wasserglasbinder (Modul 2,5) + 0,8% Additiv C - Umlaufkernsand (thermisch und mechanisch belastet)
H32 + 0,1% Additiv A + 5,0% Wasserglasbinder (Modul 2,5)
- Water glass coated molding material
H32 + 0.1% additive A + 5.0% water glass binder (modulus 2.5) + 0.8% additive C - Circulating core sand (thermally and mechanically loaded)
H32 + 0.1% additive A + 5.0% water glass binder (module 2.5)
Die Bestimmung der Rieselfähigkeit wurde bei einer Probenmenge von 350g in einem Messtrichter mit einem Innendurchmesser an dessen oberen, weiten Rand von 90 mm und einer Trichterhöhe von insgesamt 95 mm und einer Länge 32 mm und einem Innendurchmesser des Ausflussrohres von 15 mm bei Raumtemperatur von etwa 20 °C gemessen.The determination of the flowability was carried out at a sample amount of 350 g in a measuring funnel with an inner diameter at its upper, wide edge of 90 mm and funnel height of 95 mm in total and 32 mm in length and 15 mm in inner diameter of the outflow tube at room temperature of about 20 ° C measured.
Versuchsergebnis:
- Croning-Formstoff Rieselzeit: 2,9s ; 3,0s; 3,1s => 3,0s (100%)
- Wasserglasumhüllter Formstoff Rieselzeit: 3,3s ; 3,4s; 3,2s => 3,3s (90%)
- H32 Neusand Rieselzeit: 3,6s ; 3,5s; 3,5s => 3,5s (82%)
- Umlaufkernsand Rieselzeit: 3,7s ; 3,5s; 3,6s => 3,6s (80%)
- Croning molding material flow time: 2.9s; 3.0s; 3.1s => 3.0s (100%)
- Water glass coated molding material trickle time: 3.3s; 3,4S; 3.2s => 3.3s (90%)
- H32 new sand trickle time: 3.6s; 3.5s; 3.5s => 3.5s (82%)
- Circumferential sand trickle time: 3.7s; 3.5s; 3.6s => 3.6s (80%)
Aus den Versuchen ergibt sich, dass die Rieselfähigkeit des Umlaufkernsandes wesentlich schlechter ist, als die des erfindungsgemäßen umhüllten Formstoffs.The experiments show that the flowability of the circulating core sand is significantly worse than that of the coated molding material according to the invention.
Ofentemp.: 105°C; bis zur Gewichtskonstanz nach VDG Merkblatt P32 Abschnitt 4.1 vom April 1997
Der wasserglasumhüllte Formstoff besitzt nach dem Herstellungsprozess noch einen Wassergehalt bzw. Feuchteanteil (bezogen auf das Formstoffgewicht) von 0,38%.The water glass-coated molding material still has a water content or moisture content (based on the molding material weight) of 0.38% after the production process.
Der Umlaufkernsand (thermisch und mechanisch belastet) hat nur einen Feuchteanteil von 0,18%.The circulating core sand (thermally and mechanically loaded) only has a moisture content of 0.18%.
Zur Ermittlung der Biegefestigkeit wurden aus beiden Formstoffmischungen Versuchskerne (Probestäbe) hergestellt und die Biegefestigkeit gemessen.To determine the bending strength, test cores (test bars) were prepared from both molding material mixtures and the flexural strength was measured.
Versuchsparameter:
Das Ergebnis war, dass der wasserglasumhüllte erfindungsgemäße Formstoff eine durchschnittliche Biegefestigkeit von 481N/cm2 aufwies, während der Umlaufkernsand nicht bindefähig war und daraus keine Kerne hergestellt werden konnten.The result was that the water glass-coated molding material of the present invention had an average bending strength of 481N / cm 2 , while the peripheral core sand was not capable of bonding and no cores could be produced therefrom.
Eine Herstellung von Kernen durch das Einbringen von Wasserdampf ist mit dem Umlaufkernsand somit nicht möglich, und es konnte keine Bindung erzielt werden.The production of cores by the introduction of water vapor is thus not possible with the circulating core sand, and no binding could be achieved.
Claims (18)
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP08015735A EP2163328A1 (en) | 2008-09-05 | 2008-09-05 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of >= approx. 0.25 weight % to approx 0.9 weight % |
KR1020117007468A KR20110053259A (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with water glass, having a water content in the range of >= approximately 0.25 wt.% to approximately 0.9% wt.% |
BRPI0918525A BRPI0918525A2 (en) | 2008-09-05 | 2009-08-25 | soluble glass core sand or molding sand with a water content in the range of> = about 0,25% by weight to about 0,9% by weight |
JP2011525445A JP5418950B2 (en) | 2008-09-05 | 2009-08-25 | Core sand or foundry sand, method for producing core sand or foundry sand, method for producing mold part, mold part, and method of using core sand or foundry sand |
EP09778098.5A EP2323783B1 (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of > approx. 0.25 weight % to approx 0.9 weight % |
PCT/EP2009/006153 WO2010025861A1 (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with water glass, having a water content in the range of ≥ approximately 0.25 wt.% to approximately 0.9 wt.% |
CA2737334A CA2737334C (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with water glass with a water content in the range of greater than or equal to approximately 0.25% by weight to approximately 0.9% by weight |
US13/062,619 US8627877B2 (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with water glass with a water content in the range of ≧ approximately 0.25% by weight to approximately 0.9% by weight |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP08015735A EP2163328A1 (en) | 2008-09-05 | 2008-09-05 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of >= approx. 0.25 weight % to approx 0.9 weight % |
Publications (1)
Publication Number | Publication Date |
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EP2163328A1 true EP2163328A1 (en) | 2010-03-17 |
Family
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Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP08015735A Withdrawn EP2163328A1 (en) | 2008-09-05 | 2008-09-05 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of >= approx. 0.25 weight % to approx 0.9 weight % |
EP09778098.5A Active EP2323783B1 (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of > approx. 0.25 weight % to approx 0.9 weight % |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
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EP09778098.5A Active EP2323783B1 (en) | 2008-09-05 | 2009-08-25 | Core or foundry sand coated and/or mixed with soluble glass with a water content in the area of > approx. 0.25 weight % to approx 0.9 weight % |
Country Status (7)
Country | Link |
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US (1) | US8627877B2 (en) |
EP (2) | EP2163328A1 (en) |
JP (1) | JP5418950B2 (en) |
KR (1) | KR20110053259A (en) |
BR (1) | BRPI0918525A2 (en) |
CA (1) | CA2737334C (en) |
WO (1) | WO2010025861A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012175072A1 (en) | 2011-06-22 | 2012-12-27 | Voxeljet Technology Gmbh | Method for the layerwise construction of models |
WO2013159762A1 (en) * | 2012-04-26 | 2013-10-31 | Ask Chemicals Gmbh | Method for producing moulds and cores for metal casting and moulds and cores produced according to this method |
EP2853320A1 (en) * | 2013-08-26 | 2015-04-01 | Gebrüder Dorfner GmbH & Co. Kaolin- und Kristallquarzsand-Werke KG | Casting mould or a casting mould core made from coated mould sand for metal casting |
DE102014221237A1 (en) | 2013-10-19 | 2015-04-23 | Peak Deutschland Gmbh | Process for producing lost cores or moldings for casting production |
RU2650219C2 (en) * | 2012-10-19 | 2018-04-11 | Аск Кемикалз Гмбх | Molding materials mixtures based on inorganic binders and a method of producing press molds and cores for metal casting |
DE102016123050A1 (en) * | 2016-11-29 | 2018-05-30 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
RU2659562C2 (en) * | 2012-12-22 | 2018-07-02 | Аск Кемикалз Гмбх | Molding material mixtures containing metal oxides of aluminum and zirconium in particulate form |
WO2018215113A1 (en) | 2017-05-23 | 2018-11-29 | Exone Gmbh | After-treatment process for increasing the hot strength of a shaped part produced from particulate material and binder, 3d printing arrangement and shaped part |
WO2022247977A1 (en) | 2021-05-28 | 2022-12-01 | Voxeljet Ag | 3d printing method and molding part produced therewith using a water glass binder and ester |
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US11724306B1 (en) | 2020-06-26 | 2023-08-15 | Triad National Security, Llc | Coating composition embodiments for use in investment casting methods |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU424837B2 (en) * | 1966-11-07 | 1972-05-25 | Method of preparing fluid self-curing mixture for making foundry cores and moulds | |
US3804643A (en) * | 1969-05-27 | 1974-04-16 | Mitsubishi Heavy Ind Ltd | Process for producing casting molds using a dry flowable blended sand |
JPS6044147A (en) * | 1983-08-19 | 1985-03-09 | Daicel Chem Ind Ltd | Production of molding sand |
EP0739666A1 (en) * | 1995-04-28 | 1996-10-30 | General Motors Corporation | Sand mold member and method |
EP0796681A2 (en) * | 1996-02-29 | 1997-09-24 | Borden Chemical, Inc. | Binders for cores and molds |
DE19632293A1 (en) | 1996-08-09 | 1998-02-19 | Thomas Prof Dr In Steinhaeuser | Process for the production of core moldings for foundry technology |
WO1998029208A1 (en) * | 1996-12-18 | 1998-07-09 | Dti Industri | Process for preparing particles covered with a layer of water glass and articles comprising such covered particles |
WO1999058268A1 (en) * | 1998-05-11 | 1999-11-18 | Dti Industri | An infiltrated article prepared from particles covered with water glass |
WO1999058269A1 (en) * | 1998-05-11 | 1999-11-18 | Dti Industri | A process for preparing a sintered article |
DE19951622A1 (en) | 1999-10-26 | 2001-05-23 | Vaw Ver Aluminium Werke Ag | Binder system based on water glass |
DE10321106A1 (en) | 2003-05-09 | 2004-12-23 | Hydro Aluminium Deutschland Gmbh | Molded material, molded part and method for the production of moldings for a casting mold |
US20050178520A1 (en) * | 2004-02-18 | 2005-08-18 | Franklin Daniel L. | Method of drying a sand mold using a vacuum |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS50130626A (en) * | 1974-04-01 | 1975-10-16 | ||
JPS5220927A (en) * | 1975-08-12 | 1977-02-17 | Honda Motor Co Ltd | Method of making mold |
JPS6483333A (en) * | 1987-09-22 | 1989-03-29 | Honda Motor Co Ltd | Production of casting mold |
US6371194B1 (en) | 1996-08-09 | 2002-04-16 | Vaw Aluminium Ag | Method for producing core preforms and recycling core sand for a foundry |
-
2008
- 2008-09-05 EP EP08015735A patent/EP2163328A1/en not_active Withdrawn
-
2009
- 2009-08-25 US US13/062,619 patent/US8627877B2/en active Active
- 2009-08-25 WO PCT/EP2009/006153 patent/WO2010025861A1/en active Application Filing
- 2009-08-25 EP EP09778098.5A patent/EP2323783B1/en active Active
- 2009-08-25 CA CA2737334A patent/CA2737334C/en not_active Expired - Fee Related
- 2009-08-25 BR BRPI0918525A patent/BRPI0918525A2/en not_active IP Right Cessation
- 2009-08-25 JP JP2011525445A patent/JP5418950B2/en active Active
- 2009-08-25 KR KR1020117007468A patent/KR20110053259A/en not_active Application Discontinuation
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU424837B2 (en) * | 1966-11-07 | 1972-05-25 | Method of preparing fluid self-curing mixture for making foundry cores and moulds | |
US3804643A (en) * | 1969-05-27 | 1974-04-16 | Mitsubishi Heavy Ind Ltd | Process for producing casting molds using a dry flowable blended sand |
JPS6044147A (en) * | 1983-08-19 | 1985-03-09 | Daicel Chem Ind Ltd | Production of molding sand |
EP0739666A1 (en) * | 1995-04-28 | 1996-10-30 | General Motors Corporation | Sand mold member and method |
EP0796681A2 (en) * | 1996-02-29 | 1997-09-24 | Borden Chemical, Inc. | Binders for cores and molds |
EP0917499B1 (en) * | 1996-08-09 | 2000-11-22 | VAW aluminium AG | Method for the production of core preforms and recycling core sand for foundry |
DE19632293A1 (en) | 1996-08-09 | 1998-02-19 | Thomas Prof Dr In Steinhaeuser | Process for the production of core moldings for foundry technology |
EP0917499A2 (en) | 1996-08-09 | 1999-05-26 | VAW motor GmbH | Method for the production of core preforms and recycling core sand for foundry |
WO1998029208A1 (en) * | 1996-12-18 | 1998-07-09 | Dti Industri | Process for preparing particles covered with a layer of water glass and articles comprising such covered particles |
WO1999058269A1 (en) * | 1998-05-11 | 1999-11-18 | Dti Industri | A process for preparing a sintered article |
WO1999058268A1 (en) * | 1998-05-11 | 1999-11-18 | Dti Industri | An infiltrated article prepared from particles covered with water glass |
DE19951622A1 (en) | 1999-10-26 | 2001-05-23 | Vaw Ver Aluminium Werke Ag | Binder system based on water glass |
DE10321106A1 (en) | 2003-05-09 | 2004-12-23 | Hydro Aluminium Deutschland Gmbh | Molded material, molded part and method for the production of moldings for a casting mold |
US20050178520A1 (en) * | 2004-02-18 | 2005-08-18 | Franklin Daniel L. | Method of drying a sand mold using a vacuum |
Non-Patent Citations (2)
Title |
---|
BINDEMITTELPRÜFUNG, PRÜFUNG VON KALTHÄRTENDEN, KUNSTHARZGEBUNDENEN FEUCHTEN FORMSTOFFEN MIT HÄRTERZUSATZ, October 1999 (1999-10-01), pages 72 |
PRÜFUNG VON TONGEBUNDENEN FORMSTOFFEN BESTIMMUNG DES WASSERGEHALTS, April 1997 (1997-04-01), pages 32 |
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EP2723697B1 (en) * | 2011-06-22 | 2018-05-16 | Voxeljet AG | Method for the layerwise construction of models |
DE102011105688A1 (en) | 2011-06-22 | 2012-12-27 | Hüttenes-Albertus Chemische Werke GmbH | Method for the layered construction of models |
WO2012175072A1 (en) | 2011-06-22 | 2012-12-27 | Voxeljet Technology Gmbh | Method for the layerwise construction of models |
US9358701B2 (en) | 2011-06-22 | 2016-06-07 | Voxeljet Ag | Method for the layerwise construction of models |
WO2013159762A1 (en) * | 2012-04-26 | 2013-10-31 | Ask Chemicals Gmbh | Method for producing moulds and cores for metal casting and moulds and cores produced according to this method |
RU2650219C2 (en) * | 2012-10-19 | 2018-04-11 | Аск Кемикалз Гмбх | Molding materials mixtures based on inorganic binders and a method of producing press molds and cores for metal casting |
RU2659562C2 (en) * | 2012-12-22 | 2018-07-02 | Аск Кемикалз Гмбх | Molding material mixtures containing metal oxides of aluminum and zirconium in particulate form |
EP2853320A1 (en) * | 2013-08-26 | 2015-04-01 | Gebrüder Dorfner GmbH & Co. Kaolin- und Kristallquarzsand-Werke KG | Casting mould or a casting mould core made from coated mould sand for metal casting |
DE102014221237A1 (en) | 2013-10-19 | 2015-04-23 | Peak Deutschland Gmbh | Process for producing lost cores or moldings for casting production |
US10092947B2 (en) | 2013-10-19 | 2018-10-09 | Peak Deutschland Gmbh | Method for producing lost cores or molded parts for the production of cast parts |
DE102016123050A1 (en) * | 2016-11-29 | 2018-05-30 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
WO2018099894A1 (en) | 2016-11-29 | 2018-06-07 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
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CA2737334A1 (en) | 2010-03-11 |
US8627877B2 (en) | 2014-01-14 |
WO2010025861A9 (en) | 2011-04-21 |
BRPI0918525A2 (en) | 2015-12-01 |
US20110226436A1 (en) | 2011-09-22 |
JP2012501850A (en) | 2012-01-26 |
WO2010025861A1 (en) | 2010-03-11 |
EP2323783A1 (en) | 2011-05-25 |
JP5418950B2 (en) | 2014-02-19 |
KR20110053259A (en) | 2011-05-19 |
EP2323783B1 (en) | 2016-03-23 |
CA2737334C (en) | 2013-11-05 |
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