Molten metal filtration materials

Abstract

The bonding strength between the filter body and the side plate is further increased. [Solution] The molten metal filtration member 10 comprises a cylindrical filter body 20, a one-end side plate 30 having a one-end insertion hole 32 into which one end 22 of the filter body 20 is inserted, a one-end joining layer 38 that joins the outer peripheral surface 22a of the one end 22 of the filter body 20 to the inner peripheral surface 32a of the one-end insertion hole 32, an other-end side plate 40 having an other-end insertion hole 42 into which the other end 24 of the filter body 20 is inserted, and an other-end joining layer 48 that joins the outer peripheral surface 24a of the other end 24 of the filter body 20 to the inner peripheral surface 42a of the other-end insertion hole 42, and at least one of the inner peripheral surface 32a of the one-end insertion hole 32 and the inner peripheral surface 42a of the other-end insertion hole 42 has a plurality of depressions having a depth of 50 μm or more, and the average depth of the depressions is 90 μm or more and 1000 μm or less.

Description

[Technical field]

[0001] The present invention relates to a molten metal filtration member. [Background technology]

[0002] Conventionally, a molten metal filtration member is known that includes a plurality of cylindrical filter bodies with bottoms and a pair of side plates. The opposing surfaces of the pair of side plates are provided with insertion holes into which the ends of the filter bodies are inserted and held. The ends of the filter bodies are inserted and joined into the insertion holes. In this molten metal filtration member, the molten metal supplied from the outer peripheral surface of the filter body flows into the inside of the cylinder while being filtered by the filter bodies, and flows out from the end on the opening side after inclusions are removed. In such a molten metal filtration member, it has been proposed that the ratio of the distance between adjacent insertion holes to the depth of the insertion holes be 0.33 or more and 0.67 or less (see, for example, Patent Document 1). It is said that this can improve the filtration efficiency while maintaining the strength of the side plates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-210254 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, although Patent Document 1 claims that it is possible to increase the filtration efficiency while maintaining the strength of the side plates, the bonding strength between the filter body and the side plates is sometimes insufficient, and it has been desired to further increase the bonding strength between the filter body and the side plates.

[0005] The present invention has been made to solve such problems, and a main object of the present invention is to further increase the bonding strength between the filter body and the side plate. [Means for solving the problem]

[0006] [1] The molten metal filtration member of the present invention is A cylindrical filter body; a one-end side plate having a one-end insertion hole into which one end of the filter body is inserted; a one-end side bonding layer that bonds an outer peripheral surface of one end of the filter body and an inner peripheral surface of the one-end side insertion hole; an other end side plate having an other end side insertion hole into which the other end of the filter body is inserted; an other-end side bonding layer that bonds an outer peripheral surface of the other end of the filter body and an inner peripheral surface of the other-end side insertion hole; having At least one of the inner peripheral surface of the one end side insertion hole and the inner peripheral surface of the other end side insertion hole has a plurality of recesses having a depth of 50 μm or more, and the average depth of the recesses is 90 μm or more and 1000 μm or less.

[0007] In this molten metal filtration member, at least one of the inner peripheral surface of the one end side insertion hole and the inner peripheral surface of the other end side insertion hole has a plurality of recesses with a depth of 50 μm or more, and the average depth is 90 μm to 1000 μm. Side Panel This increases the bonding strength between the bonding layer and the filter body, thereby making it possible to further increase the bonding strength between the filter body and the side plate.

[0008] [2] In the molten metal filtration member of the present invention (the molten metal filtration member described in [1] above), it is preferable that the average depth of the recesses is 200 μm or more and 1000 μm or less on at least one of the inner peripheral surface of the one end side insertion hole and the inner peripheral surface of the other end side insertion hole. This makes it possible to further increase the bonding strength between the filter body and the side plate.

[0009] [3] In the molten metal filtration member of the present invention (the molten metal filtration member described in [1] or [2] above), at least one of the inner peripheral surface of the one end insertion hole and the inner peripheral surface of the other end insertion hole preferably has an average surface roughness Ra of 50 μm or more and 600 μm or less. This can further increase the bonding strength between the filter body and the side plate.

[0010] [4] In the molten metal filtration member of the present invention (the molten metal filtration member according to any one of [1] to [3] above), the average width of the recesses is preferably 200 μm or more and 500 μm or less on the inner peripheral surface of the one end insertion hole and the inner peripheral surface of the other end insertion hole. This can further increase the bonding strength between the filter body and the side plate.

[0011] [5] In the molten metal filtration member of the present invention (the molten metal filtration member according to any one of the above [1] to [4]), the number of the dents present on a straight line having a length of 15 mm on at least one of the inner peripheral surface of the one end insertion hole and the inner peripheral surface of the other end insertion hole is preferably 4 to 30. This can further increase the bonding strength between the filter body and the side plate.

[0012] [6] The molten metal filtration member of the present invention (the molten metal filtration member described in any one of [1] to [5] above) may have a maximum load of 1.5 kN or more applied to push out the filter body in at least one of the one end insertion hole and the other end insertion hole. [Brief description of the drawings]

[0013] [Figure 1] FIG. [Diagram 2] FIG. 2 is a cross-sectional view of the molten metal filtration member 10. [Diagram 3] 1 is an explanatory diagram of an example of use of the molten metal filtration member 10. FIG. [Figure 4] FIG. 13 is an explanatory diagram of a measurement example of the inner circumferential surface of an insertion hole. [Diagram 5] FIG. 4 is an explanatory diagram of a measurement example of push-out strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A preferred embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view of a molten metal filtration member 10. Fig. 2 is a cross-sectional view of the molten metal filtration member 10 (a cross-sectional view cut along a cross section including the central axis of the filter body 20).

[0015] The molten metal filtration member 10 includes a filter body 20, a one-end side plate 30 having a one-end insertion hole 32 into which one end 22 of the filter body 20 is inserted, and an other-end side plate 40 having a other-end insertion hole 42 into which the other end 24 of the filter body 20 is inserted. Here, the molten metal filtration member 10 includes 14 filter bodies 20, which are arranged at intervals to form a staggered arrangement. The outer peripheral surface 22a of the one end 22 of the filter body 20 and the inner peripheral surface 32a of the one-end insertion hole 32 are joined by a one-end joining layer 38. The outer peripheral surface 24a of the other end 24 of the filter body 20 and the inner peripheral surface 42a of the other-end insertion hole 42 are joined by a other-end joining layer 48. A one-end packing 39 is arranged between the end surface 22b of the one end 22 of the filter body 20 and the bottom surface 32b of the one-end insertion hole 32. An other-end packing 49 is disposed between the end face 24 b of the other end 24 of the filter body 20 and the bottom face 42 b of the other-end insertion hole 42 .

[0016] The filter body 20 is a porous cylindrical member formed of a ceramic material such as alumina or silicon carbide. The filter body 20 is made of a material such as alumina aggregate, aluminum borate (9Al 2 O 3 2B 2 O 3 The inorganic binder may be bonded with an inorganic binder such as cellulose acetate. The inorganic binder may be, for example, a needle-like crystal having an aspect ratio of 2 to 50. The filter body 20 is cylindrical with a hole 20h coaxial with the filter body 20, and one end 22 is open and the other end 24 is closed. A part of the outer circumferential surface 24a of the other end 24 is a tapered surface 24c that is reduced in diameter toward the end surface 24b. The filter body 20 has, for example, a length of about 870 mm, an outer diameter of about 100 mm, and an inner diameter of about 60 mm. The dimensions of the filter body 20 may be appropriately adjusted depending on the number of filter bodies 20.

[0017] The one end side plate 30 is a dense plate-like member made of a ceramic material such as silicon carbide. Note that the term "dense" means that the material is dense enough that molten metal does not pass through (hereinafter the same). The ceramic material is, for example, SiO 2 Bonded SiC(SiO 2 -SiC) and Si3 N 4 Bonded SiC(Si 3 N 4 -SiC) may be used. A one-end insertion hole 32 is provided in one main surface 31 of the one-end side plate 30. The one-end insertion hole 32 is a circular recess that opens in the main surface 31, and its inner diameter is larger than the outer diameter of the filter body 20. A through hole 32h is provided in the bottom surface 32b of the one-end insertion hole 32, which is coaxial with the one-end insertion hole 32 and penetrates to the other main surface of the one-end side plate 30. The through hole 32h is formed to have approximately the same diameter as the hole 20h of the filter body 20. For example, the one-end side plate 30 has a thickness of about 50 mm, and the depth of the one-end insertion hole 32 is about 28 mm. The inner peripheral surface 32a of the one-end insertion hole 32 may be expanded in diameter from the bottom surface 32b toward the opening side. In this case, the inclination of the inner peripheral surface 32a with respect to the axis of the one-end insertion hole 32 may be about 2.0°. The one end side plate 30 can be produced, for example, by mixing raw material powder (aggregate), an organic binder, and water to prepare a clay, forming the clay into the shape of the one end side plate 30, and firing it. The particle size distribution of the aggregate may be such that the particle size exceeding 2000 μm is 1.0% to 15.0%, the particle size exceeding 500 μm and not more than 2000 μm is 30.0% to 60.0%, the particle size exceeding 90 μm and not more than 500 μm is 10.0% to 30.0%, and the particle size not more than 90 μm is 20.0% to 35.0%. The particle size distribution of the aggregate is preferably such that the particle size exceeding 500 μm is 50.0% or more, more preferably 60.0% or more, and even more preferably 65.0% or more. The particle size distribution is measured by mass standard using a vibrating sieve in accordance with JIS Z 8815-1994. The aggregate is preferably SiC. The clay preferably contains 80.0 mass% or more of SiC. The clay may contain 98.0 mass% or less of SiC. The clay preferably has a moisture content of 2.0 mass% or more and 5.0 mass% or less. Clay or a sintering aid may be added to the clay. The inner peripheral surface 32a and the bottom surface 32b of the one-end insertion hole 32 may be machined surfaces or may be fired surfaces as fired.

[0018] The inner circumferential surface 32a of the one-end insertion hole 32 has a plurality of recesses each having a depth of 50 μm or more. The average depth (also referred to as the average depth) of these recesses (recesses having a depth of 50 μm or more, the same applies below) is 90 μm or more and 1000 μm or less. The average depth is preferably 100 μm or more, more preferably 200 μm or more, and may be 300 μm or more. The average width (also referred to as the average width) of these recesses may be 200 μm or more, 300 μm or more, or 400 μm or more. The average width may be 700 μm or less, 600 μm or less, or 500 μm or less. The number of these recesses present on a straight line having a length of 15 mm may be 4 or more, 5 or more, or 8 or more. The number of the recesses on a straight line of 15 mm in length may be 30 or less, 20 or less, or 15 or less. The average value of the arithmetic surface roughness Ra (also referred to as the average surface roughness Ra) of the inner peripheral surface 32a of the one-end insertion hole 32 may be 50 μm or more, 100 μm or more, or 150 μm or more. The average surface roughness Ra may be 1000 μm or less, 800 μm or less, or 600 μm or less. The arithmetic average roughness Ra is a value measured in accordance with JIS B0601-2001. The average depth, average width, and number of recesses and the average surface roughness Ra of the inner peripheral surface 32a may be measured on an arbitrary straight line of 15 mm in length in the insertion direction of the filter body 20 (left and right direction in FIG. 2) in a representative portion of the inner peripheral surface 32a, or may be the average value measured on multiple straight lines (for example, three lines). The average depth, average width, number of the recesses, and average roughness of the inner peripheral surface 32a can be adjusted as appropriate, for example, by adjusting the particle size distribution of the raw material powder used when producing the one-end side panel 30 or the moisture content of the clay.

[0019] The one-end bonding layer 38 is disposed between the outer peripheral surface 22a of the one end 22 of the filter body 20 and the inner peripheral surface 32a of the one-end insertion hole 32 to bond them together. The one-end bonding layer 38 adheres the outer peripheral surface 22a of the one end 22 of the filter body 20 to the inner peripheral surface 32a of the one-end insertion hole 32 to such an extent that molten metal does not enter between them. The one-end bonding layer 38 may be formed of, for example, mortar. The mortar is preferably an alumina mortar, and more preferably one containing 75 mass% or more of alumina. The proportion of alumina contained in the mortar may be 95 mass% or less. The alumina mortar can suppress contamination of molten metal such as molten aluminum. This mortar is preferably made of SiO 2 The mortar may contain a glass component such as fluorine, which is soft when hot when filtering the molten metal, but is hard when cold before or after use. The mortar may be hardened by natural drying and / or heat drying at a temperature of 100° C. or less. The thickness of the one-end bonding layer 38 is, for example, about 1.5 mm.

[0020] The one-end packing 39 is disposed between the end surface 22b of the one end 22 of the filter body and the bottom surface 32b of the one-end insertion hole 32, and mainly absorbs the longitudinal dimensional change caused by the thermal expansion and contraction of the filter body 20, and maintains the adhesion between the filter body 20 and the one-end side plate 30. The one-end packing 39 is formed in an annular shape having a hole 39h that is approximately the same diameter as the bottom surface 32b of the one-end insertion hole 32 and connects the hole 20h of the filter body 20 and the through hole 32h of the one-end insertion hole 32. The one-end packing 39 may be formed of ceramic fiber such as alumina fiber. The thickness of the one-end packing 39 is, for example, about 12 mm.

[0021] The other end side plate 40 is a dense plate-like member made of a ceramic material such as silicon carbide. The ceramic material is, for example, SiO 2 Bonded SiC(SiO 2 -SiC) and Si 3 N 4 Bonded SiC(Si 3 N 4-SiC) may be used. An other end side insertion hole 42 is provided in one main surface 41 of the other end side plate 40. The other end side insertion hole 42 is a circular recess that opens in the main surface 41, and its inner diameter is formed to be larger than the outer diameter of the filter body 20. No through hole is provided in the bottom surface 42b of the other end side insertion hole 42. The other end side plate 40 has a thickness of, for example, about 45 mm, and the other end side insertion hole 42 has a depth of about 28 mm. The inner peripheral surface 42a of the other end side insertion hole 42 may be expanded in diameter from the bottom surface 42b toward the opening side. In this case, the inclination of the inner peripheral surface 42a with respect to the axis of the other end side insertion hole 42 may be about 4.0°. The other end side plate 40 can be produced, for example, by mixing raw material powder (aggregate), an organic binder and water to prepare a clay, forming the clay into the shape of the other end side plate 40, and firing the clay. The particle size distribution and material of the aggregate, the proportion of SiC in the clay, and the moisture content can be the same as those described for the one end side plate 30. Clay or a sintering aid may be added to the clay. The inner peripheral surface 42a and bottom surface 42b of the other end insertion hole 42 may be machined surfaces, or may be fired surfaces as they are.

[0022] The inner circumferential surface 42a of the other end insertion hole 42 has a plurality of recesses each having a depth of 50 μm or more. The average depth (also referred to as the average depth) of these recesses (recesses having a depth of 50 μm or more, the same applies below) is 90 μm or more and 1000 μm or less. The average depth is preferably 100 μm or more, more preferably 200 μm or more, and may be 300 μm or more. The average width (also referred to as the average width) of these recesses may be 200 μm or more, 300 μm or more, or 400 μm or more. The average width may be 700 μm or less, 600 μm or less, or 500 μm or less. The number of these recesses present on a straight line having a length of 15 mm may be 4 or more, 5 or more, or 8 or more. The number of the recesses on a straight line of 15 mm in length may be 30 or less, 20 or less, or 15 or less. The average value of the arithmetic surface roughness Ra (also referred to as the average surface roughness Ra) of the inner peripheral surface 42a of the other end side insertion hole 42 may be 50 μm or more, 100 μm or more, or 150 μm or more. The average surface roughness Ra may be 1000 μm or less, 800 μm or less, or 600 μm or less. The arithmetic average roughness Ra is a value measured in accordance with JIS B0601-2001. The average depth, average width, and number of recesses and the average surface roughness Ra of the inner peripheral surface 42a may be measured on an arbitrary straight line of 15 mm in length in the insertion direction of the filter body 20 (left and right direction in FIG. 2) in a representative portion of the inner peripheral surface 42a, or may be an average value obtained by measuring multiple straight lines (for example, three lines). The average depth, average width, number of the recesses, and average roughness of the inner peripheral surface 42a can be adjusted as appropriate, for example, by adjusting the particle size distribution of the raw material powder used in producing the other end side panel 40 or the moisture content of the clay.

[0023] The other end side bonding layer 48 is disposed between the outer peripheral surface 24a of the other end 24 of the filter body 20 and the inner peripheral surface 42a of the other end side insertion hole 42 to bond them together. The other end side bonding layer 48 adheres the outer peripheral surface 24a of the other end 24 of the filter body 20 to the inner peripheral surface 42a of the other end side insertion hole 42 to such an extent that molten metal does not enter between them. The other end side bonding layer 48 may be formed of, for example, mortar. The mortar may be the same as the mortar described for the one end side bonding layer 38. The thickness of the other end side bonding layer 48 is, for example, about 1.5 mm.

[0024] The other end packing 49 is disposed between the end surface 24b of the other end 24 of the filter body 20 and the bottom surface 42b of the other end insertion hole 42, and mainly absorbs longitudinal dimensional changes caused by thermal expansion and contraction of the filter body 20, and maintains close contact between the filter body 20 and the other end side plate 40. The other end packing 49 is formed in a circular shape with approximately the same diameter as the bottom surface 42b of the other end insertion hole 42. The other end packing 49 may be formed of ceramic fiber such as alumina fiber. The thickness of the other end packing 49 is, for example, about 12 mm.

[0025] A manufacturing example of the molten metal filtration member 10 will be described. First, the other end side plate 40 is prepared, and the material of the other end side packing 49 is placed on the bottom surface 42b of the other end side insertion hole 42. Then, the material (mortar) of the other end side bonding layer 48 is applied to the inner peripheral surface 42a of the other end side insertion hole 42 and the outer peripheral surface 24a of the other end 24 of the filter body 20, and the other end 24 of the filter body 20 is inserted into the other end side insertion hole 42 to a predetermined depth. Also, the one end side plate 30 is prepared, and the material of the one end side packing 39 is placed on the bottom surface 32b of the one end side insertion hole 32. Then, the material (mortar) of the one end side bonding layer 38 is applied to the inner peripheral surface 32a of the one end side insertion hole 32 and the outer peripheral surface 22a of the one end 22 of the filter body 20, and the one end 22 of the filter body 20 is inserted into the one end side insertion hole 32 to a predetermined depth. Thereafter, natural drying and / or heat drying is performed at a temperature of, for example, 100° C. or less, whereby the filter body 20 is joined to the one end side plate 30 and the other end side plate 40, and the molten metal filtration member 10 is obtained.

[0026] An example of use of the molten metal filtration member 10 will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram of an example of use of the molten metal filtration member 10. The molten metal filtration member 10 is fixed in a filtration chamber 52 of a storage tank 50 for use. The storage tank 50 is a container lined with a refractory material such as firebricks, and is separated into a filtration chamber 52 and a molten metal discharge chamber 56 by a partition wall 54. An inlet 51 is provided at the top of the side wall of the filtration chamber 52, an opening 53 is provided in the partition wall 54, and an outlet 57 is provided in the side wall of the molten metal discharge chamber 56 at a position lower than the inlet 51. The molten metal filtration member 10 is arranged in the filtration chamber 52 of the storage tank 50 such that the other end side plate 40 is on the inlet 51 side and the one end side plate 30 is on the partition wall 54 side. Then, when the wedge 59 is driven between the other end side plate 40 and the side wall of the filtration chamber 52, the one end side plate 30 comes into contact with the partition wall 54, and the molten metal filtration member 10 is fixed in the filtration chamber 52. In this state, when molten metal such as aluminum metal or aluminum alloy is supplied from the inlet 51 of the storage tank 50, the molten metal passes from the outer peripheral surface of the filter body 20 through the pores of the filter body 20 to the hole 20h, during which solid impurities such as oxides are filtered. Thereafter, the molten metal from which the solid impurities have been removed passes through the opening 53 provided in the partition wall 54, accumulates in the discharge chamber 56, is discharged from the outlet 57, and is used to manufacture metal foil, metal plate, metal parts, and the like. The filtration performance of the molten metal filtration member 10 decreases with use, but it is configured as a cartridge that can be replaced by inserting and removing the wedge 59, and the storage tank 50 can be used continuously by simply replacing the molten metal filtration member 10. Here, if the joint strength between the filter body 20 and the one end side plate 30 or the other end side plate 40 is weak, the joint between the two may come loose when the molten metal filtration member 10 is transported or set in or removed from the storage tank 50. Also, if the joint between the two comes loose before the molten metal filtration member 10 is set in the storage tank 50, there is a risk that the molten metal cannot be stably filtered. However, in the molten metal filtration member 10 of the present invention, the joint strength between the filter body 20 and the one end side plate 30 or the other end side plate 40 is strong, and filtration can be performed stably. In this way, the present invention can provide a highly reliable molten metal filtration member 10.

[0027] In the molten metal filtration member 10 described above, the inner circumferential surface 32a of the one-end insertion hole 32 and the inner circumferential surface 42a of the other-end insertion hole 42 have a plurality of recesses with a depth of 50 μm or more, and the average depth is 90 μm or more and 1000 μm or less. Therefore, the one-end bonding layer 38 and the other-end bonding layer 48 are appropriately inserted into the recesses, and the bonding strength between the filter body 20 and the one-end bonding layer 38 and the other-end bonding layer 48 is increased, and the bonding strength between the filter body 20 and the one-end side plate 30 and the other-end side plate 40 can be further increased. As a result, a highly reliable molten metal filtration member 10 can be provided. Note that, when the average depth of the recesses is 1000 μm or less, damage to the side plate originating from the recesses is less likely to occur, which is desirable.

[0028] In this molten metal filtration member 10, the one-end side punching strength, which is the maximum load applied when pushing the filter body 20 through the one-end side insertion hole 32, may be 1.5 kN or more. This one-end side punching strength is preferably 2 kN or more, more preferably 3 kN or more, and even more preferably 4 kN or more. In addition, in this molten metal filtration member 10, the other-end side punching strength, which is the maximum load applied when pushing the filter body 20 through the other-end side insertion hole 42, may be 1.5 kN or more. This other-end side punching strength is preferably 2 kN or more, more preferably 3 kN or more, and even more preferably 4 kN or more.

[0029] It goes without saying that the present invention is not limited to the above-described embodiment, and can be embodied in various forms within the technical scope of the present invention.

[0030] For example, in the above-described embodiment, both the inner circumferential surface 32a of the one-end insertion hole 32 and the inner circumferential surface 42a of the other-end insertion hole 42 have a plurality of recesses with a depth of 50 μm or more and an average depth of 90 μm to 1000 μm, but this is not limited thereto. For example, when stress is particularly concentrated between the inner circumferential surface 32a of the one-end insertion hole 32 and the one-end bonding layer 38 due to differences in the shapes and arrangements of the respective members, only the inner circumferential surface 32a may satisfy this. Also, when stress is particularly concentrated between the inner circumferential surface 42a of the other-end insertion hole 42 and the one-end bonding layer 48, only the inner circumferential surface 42a may satisfy this.

[0031] In the above embodiment, the other end 24 of the filter body 20 is closed, but may be open. In addition, no through hole is provided in the bottom surface 42b of the other end side insertion hole 42, but a through hole may be provided. In addition, part of the outer circumferential surface 24a of the other end 24 is tapered surface 24c, but it does not have to be tapered surface 24c. EXAMPLES

[0032] Hereinafter, examples in which the bonding strength between the filter body and the side plate of the molten metal filtration member of the present invention was examined will be described as examples. Note that Experimental Examples 2 to 11 correspond to examples of the present invention, and Experimental Example 1 corresponds to a comparative example of the present invention.

[0033] [Experimental Example 1] (Making the side panels) The side panels were fabricated as follows. First, powder containing 0% SiC with a particle size exceeding 2000 μm, 35% SiC with a particle size exceeding 500 μm and 2000 μm or less, 30% SiC with a particle size exceeding 90 μm and 500 μm or less, and 35% SiC with a particle size of 90 μm or less was used as the raw powder (aggregate). This powder was mixed with carboxymethyl cellulose (CMC) as an organic binder and water to obtain a clay with a moisture content of 5.5 mass%. The clay was added with clay and a sintering aid. This clay was molded and fired at 1430 °C in an air atmosphere for 3 hours to obtain a side panel. The thickness of the side panel was 50 mm, the diameter of the insertion hole was 104 mm, and the depth was 28 mm. In addition, a through hole with a diameter of 56 mm was provided at the bottom of the insertion hole. Then, a packing made of alumina fiber and having a thickness of approximately 12 mm was placed at the bottom of the insertion hole.

[0034] (Joining of side plate and filter body) A filter body made of a porous material in which alumina aggregate was bound with needle-shaped crystals of aluminum borate was prepared. This filter body had a length of approximately 870 mm, an outer diameter of 100 mm, an inner diameter of 60 mm, one end was open and the other end was closed, and the thickness of the bottom was 20 mm. This filter body was processed so that the length was approximately 200 mm, leaving the bottom. Then, Al was applied to the outer peripheral surface of the opening side of the filter body and the inner peripheral surface of the insertion hole in the side plate. 2 O 3 85% by mass and SiO 2 The filter body was then coated with mortar containing 2% by mass of the above-mentioned mortar, and the open side of the filter body was inserted into the insertion hole of the side plate. The filter body was then naturally dried for 12 hours, and then heated and dried at 80°C for 12 hours to bond the side plate and the filter body. Only one filter body was used.

[0035] (Measurement of the inner surface of the insertion hole) The side plate was split, and the part where the inner circumferential surface of the insertion hole could be observed was taken out as a test piece. Surface measurements were performed on a straight line with a length of 15 mm for three representative locations of this test piece. For the measurements, a Keyence VR-3000 one-shot 3D measuring microscope was used to measure the arithmetic surface roughness Ra, the number of dents (pieces / 15 mm), the width of the dents (μm), and the depth of the dents (μm), and the average values ​​were calculated. Note that only dents with a depth of 50 μm or more were measured for the number, width, and depth. Figure 4 shows an explanatory diagram of a measurement example of the inner circumferential surface of the insertion hole. Figure 4A is an explanatory diagram showing the observation direction. Figure 4B is a photograph of the test piece. Figure 4C is a contour diagram showing the height of the test piece. Figure 4D is an example of a measured roughness curve.

[0036] (Measurement of punching strength) An explanatory diagram of a measurement example of the push-out strength is shown in Figure 5. As shown in Figure 5, a test jig was inserted through the through hole of the side plate and pressed to apply a load to the bottom surface of the filter body. Then, the load when the filter body was pushed out of the side plate was measured as the push-out strength (kN).

[0037] [Experimental Examples 2-11] The side panels were produced in the same manner as in Experimental Example 1, except that the particle size distribution of the aggregate (SiC) in the raw material powder and the moisture content of the clay were as shown in Table 1.

[0038] [Experimental Results] Table 1 summarizes the measurement results of the inner peripheral surface of the insertion hole and the measurement results of the punching strength. As shown in Table 1, in Experimental Examples 2 to 11 in which the inner peripheral surface of the insertion hole has a plurality of recesses with a depth of 50 μm or more and an average depth of 90 μm to 1000 μm, the punching strength was 1.5 kN, and it was found that the bonding strength between the filter body and the side plate can be further increased. Note that, although the bonding strength of the open end side of the filter body was evaluated here, it is presumed that the same result would be obtained for the bonding strength of the closed end side of the filter body.

[0039] [Table 1] [Industrial Applicability]

[0040] The present invention can be used in the field of manufacturing metal products. [Explanation of symbols]

[0041] 10 molten metal filtration member, 20 filter body, 20h hole, 22 one end, 22a outer peripheral surface, 22b end surface, 24 other end, 24a outer peripheral surface, 24b end surface, 30 one end side plate, 32 one end insertion hole, 32a inner peripheral surface, 32b bottom surface, 32h through hole, 38 one end bonding layer, 39 one end packing, 40 other end side plate, 42 other end insertion hole, 42a inner peripheral surface, 42b bottom surface, 48 other end bonding layer, 49 other end packing, 50 storage tank, 51 inlet, 52 filtration chamber, 53 opening, 54 partition wall, 56 molten metal discharge chamber, 57 outlet, 59 wedge.

Claims

1. A cylindrical filter body; a one-end side plate having a one-end insertion hole into which one end of the filter body is inserted; a one-end side bonding layer that bonds an outer peripheral surface of one end of the filter body and an inner peripheral surface of the one-end side insertion hole; an other end side plate having an other end side insertion hole into which the other end of the filter body is inserted; an other-end side bonding layer that bonds an outer peripheral surface of the other end of the filter body and an inner peripheral surface of the other-end side insertion hole; having At least one of the inner circumferential surface of the one end side insertion hole and the inner circumferential surface of the other end side insertion hole is The substrate has a plurality of recesses each having a depth of 50 μm or more, and the average depth of the recesses is 90 μm or more and 1000 μm or less; the bonding layer is a mortar containing alumina and silica, the side plate contains an aggregate of silicon carbide, and the particle size distribution of the aggregate is such that the particle size exceeding 2000 μm is 8% or more and 15.0% or less, the particle size exceeding 500 μm and 2000 μm or less is 30.0% or more and 60.0% or less, the particle size exceeding 90 μm and 500 μm or less is 10.0% or more and 30.0% or less, and the particle size equal to or less than 90 μm is 20.0% or more and 35.0% or less, and the filter body is made of a porous material in which alumina aggregate is bonded with needle-like crystals of aluminum borate. Molten metal filtration material.

2. The average depth of the recess is 200 μm or more and 1000 μm or less on at least one of the inner circumferential surface of the one end side insertion hole and the inner circumferential surface of the other end side insertion hole. The molten metal filtration member according to claim 1 .

3. At least one of the inner circumferential surface of the one end side insertion hole and the inner circumferential surface of the other end side insertion hole has an average surface roughness Ra of 50 μm or more and 600 μm or less. The molten metal filtration member according to claim 1 .

4. The average width of the recess is 200 μm or more and 500 μm or less on at least one of the inner circumferential surface of the one end side insertion hole and the inner circumferential surface of the other end side insertion hole. The molten metal filtration member according to any one of claims 1 to 3.

5. the number of the recesses existing on a straight line having a length of 15 mm on at least one of the inner peripheral surface of the one end side insertion hole and the inner peripheral surface of the other end side insertion hole is 4 or more and 30 or less; The molten metal filtration member according to any one of claims 1 to 3.

6. In at least one of the one end side insertion hole and the other end side insertion hole, a maximum load applied to push out the filter body is 3.5 kN or more when the diameter of the insertion hole is 104 mm, the depth is 28 mm, and the outer diameter of the filter body is 100 mm. The molten metal filtration member according to any one of claims 1 to 3.

7. At least one of the inner peripheral surface of the one end side insertion hole and the inner peripheral surface of the other end side insertion hole has a plurality of recesses having a depth of 50 μm or more when measured on an arbitrary straight line of 15 mm in length in the insertion direction of the filter body, and the average depth of the recesses is 90 μm or more and 1000 μm or less. The molten metal filtration member according to any one of claims 1 to 3.

8. The molten metal filtration member according to any one of claims 1 to 3, wherein at least one of the inner circumferential surface of the one end insertion hole and the inner circumferential surface of the other end insertion hole has an average surface roughness Ra of 50 μm or more and 600 μm or less when measured on an arbitrary straight line with a length of 15 mm in the insertion direction of the filter body.

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