Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D43/00—Mechanical cleaning, e.g. skimming of molten metals
  • B22D43/001—Retaining slag during pouring molten metal
  • B22D43/004—Retaining slag during pouring molten metal by using filtering means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D43/00—Mechanical cleaning, e.g. skimming of molten metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
  • B22C9/086—Filters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
  • B22D21/02—Casting exceedingly oxidisable non-ferrous metals, e.g. in inert atmosphere
  • B22D21/04—Casting aluminium or magnesium
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide

Definitions

• the present invention relates to a filter for molten aluminum used for filtering inclusions mixed in the molten aluminum.
• aluminum is formed into a thin plate or the like by casting an aluminum melt to produce an ingot. If non-metallic inclusions are mixed in the molten aluminum, surface defects may occur during rolling. Therefore, in order to remove these, the molten aluminum is filtered using a filter.
• a filter for example, 100 parts by weight of aggregate particles composed of at least one of electrofused alumina and sintered alumina are bonded with 10 to 20 parts by weight of an inorganic binder, and the raw material of the inorganic binder is used.
• the composition consists of SiO 2 exceeding 25 wt% to 35 wt%, B 2 O 3 30 to 40 wt%, Al 2 O 3 20 to 35 wt%, and the balance MgO.
• a filter see Patent Document 1 below
• the binder consists of an aggregate particle composed of one or both of fused alumina and sintered alumina and a binder, and the binder is present in an amount of 10 to 22 parts by weight per 100 parts by weight of the aggregate particles.
• the binder contains 15 to 35% by weight of Al 2 O 3 , 35 to 52% by weight of B 2 O 3 , 7% to less than 15% by weight of SiO 2 , and the balance is MgO.
• a ceramic filter for filtering molten metal see Patent Document 2 below).
• a filter medium for molten aluminum in which aggregate particles made of one or more of sintered alumina, electrofused alumina, silicon carbide and silicon nitride are bonded with an inorganic binder, and the amount is 4 to 20 with respect to 100 parts by weight of the aggregate particles. It is attached at the inorganic binder weight parts, the raw material composition of the inorganic binder, B 2 O 3 15 to 40 wt%, the Al 2 O 3 20 ⁇ 45 wt%, a SiO 2 15 ⁇ 25
• a filter material for molten aluminum wherein the weight percent and the balance are at least one of MgO, CaO and SrO (see Patent Document 3 below).
• a filter material for molten metal (see Patent Document 4 below) characterized by acicular crystals deposited on the surface of a ceramic filler has been developed.
• the filtration performance of the filter has been improved and inclusions in the molten aluminum have been removed as much as possible.
• a crystal grain refining agent such as TiB 2 is mixed in the molten aluminum in order to refine crystal grains. If the filtration performance is too good, the crystal grain refining agent will also be removed, and the aluminum cast from such a molten metal will coarsen the crystal grains and cause defects such as ingot cracking. There was a problem.
• an object of the present invention is to provide a filter for molten aluminum that can pass a suitable amount of crystal grain refining agent such as TiB 2 and can remove other inclusions.
• the filter for molten aluminum according to the present invention is a filter for molten aluminum formed by combining 100 parts by weight of aggregate particles containing alumina with 5 to 20 parts by weight of an inorganic binder, 7 to 15 wt% of SiO 2 , 40 to 60 wt% of B 2 O 3 , 5 to 30 wt% of Al 2 O 3 , the balance is MgO, etc., and Na 2 O is 0.01 to 0.5 wt% in the filter. %, K 2 O in an amount of 0.01 to 0.5 wt%, and CaO in an amount of 0.1 to 0.5 wt%.
• filtration filter for molten aluminum of the present invention the average length of the needle-like crystals of 9Al 2 O 3 ⁇ 2B 2 O 3 to produce the inorganic binder in the 2 [mu] m ⁇ 20 [mu] m, and the length 20 [mu] m or more needles
• the ratio of the crystal is 5% or less.
• the filter filter for molten aluminum has a filter firing temperature of 1100 to 1400 ° C.
• the filter of the present invention has a TiB 2 capture rate of 40 to 60%, a bending strength at 800 ° C. of 2 MPa or more, and can pass an appropriate amount of a crystal grain refining agent such as TiB 2 .
• a casting cast from molten aluminum has less ingot cracking and is not damaged by handling.
• the molten aluminum includes molten aluminum alloy.
• the filter for molten aluminum according to an embodiment of the present invention “hereinafter referred to as the present filter” is formed by binding 5 to 20 parts by weight of an inorganic binder to 100 parts by weight of aggregate particles made of alumina. It is.
• the binder comprises Al 2 O 3 5 ⁇ 30wt% , preferably includes a like MgO to the remainder.
• alumina Al 2 O 3
• fused alumina or sintered alumina can be used.
• this filter preferably contains Na 2 O, K 2 O, and CaO as alkali components, and these contain 0.01 to 0.5 wt% of Na 2 O and 0.02 of K 2 O in the filter. It is preferable to contain 01 to 0.5 wt% and CaO 0.1 to 0.5 wt%.
• the inorganic binder of the present filter, 9Al 2 O 3 ⁇ 2B 2 O 3 of the needle-like crystals are generated, average length is 2 [mu] m ⁇ 20 [mu] m, and, more length 20 [mu] m of the needles
• the proportion is preferably 5% or less.
• the average length and ratio of the acicular crystals can be measured as shown in the following examples.
• the above-mentioned inorganic binder is added to 100 parts by weight of aggregate particles made of fused alumina or sintered alumina, and Na 2 O, K 2 O, It can be produced by adding an appropriate amount of an alkali component of CaO, an organic binder such as a polysaccharide, water and the like, kneading, molding, drying and sintering. This firing is preferably performed at 1100 to 1400 ° C.
• This filter, the inorganic binding material, 9Al 2 O 3 ⁇ 2B 2 O 3 of the needle-like crystals are generated, average length is 2 [mu] m ⁇ 20 [mu] m, and, more length 20 [mu] m of the needles The proportion is 5% or less. For this reason, 40-60% of the finer such as TiB 2 in the molten metal is captured, but since an appropriate amount of the finer passes through, the casting cast from the molten metal filtered by this filter will cause ingot cracking, etc. There will be fewer defects.
• this filter has a bending strength at 800 ° C. of 2 MPa or more and is not damaged during handling.
• bending strength can be measured as shown in the following Example.
• Electrofused alumina # 24 is used as aggregate particles, and an inorganic binder is added to 100 parts by weight of this in proportions shown in Tables 1 and 2 below, and an appropriate amount of alkali, organic binder and water are added. After kneading and casting into a pipe shape having an outer diameter of 100 mm ⁇ inner diameter of 60 mm ⁇ length of 870 mm, it is dried and fired at the temperatures shown in Tables 1 and 2 below. Examples 1 to 16 and Comparative Examples 1 to Thirteen filters were made.
• Capture rate The filter of each Example and the comparative example was attached to the filtration apparatus, and the molten aluminum to which TiB 2 was added was filtered. B (boron) before and after filtration was analyzed and the capture rate was measured.
• Examples 1 to 16 are evaluations of comprehensive judgment “ ⁇ ” or “ ⁇ ”, and these are 7 to 15 wt% of SiO 2 , 40 to 60 wt% of B 2 O 3 , and Al 2 in the inorganic binder.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Ceramic Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Filtering Materials (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)

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• 2009
  • 2009-10-09 JP JP2009235698A patent/JP4701301B2/ja active Active
• 2010
  • 2010-09-08 CN CN2010800443870A patent/CN102686340B/zh active Active
  • 2010-09-08 WO PCT/JP2010/065376 patent/WO2011043150A1/ja active Application Filing
  • 2010-09-08 KR KR1020127006737A patent/KR101160531B1/ko active IP Right Grant

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