WO2011010671A1 - Process for production of metal-bonded grinding stone, and sintering furnace for production of metal-bonded grinding stone - Google Patents

Process for production of metal-bonded grinding stone, and sintering furnace for production of metal-bonded grinding stone Download PDF

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Publication number
WO2011010671A1
WO2011010671A1 PCT/JP2010/062258 JP2010062258W WO2011010671A1 WO 2011010671 A1 WO2011010671 A1 WO 2011010671A1 JP 2010062258 W JP2010062258 W JP 2010062258W WO 2011010671 A1 WO2011010671 A1 WO 2011010671A1
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Prior art keywords
metal bond
pressure
inert gas
bond grindstone
furnace
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PCT/JP2010/062258
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French (fr)
Japanese (ja)
Inventor
正人 氏橋
俊也 平田
和彦 北中
直秀 海野
宏 杉山
規之 難波
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本田技研工業株式会社
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Priority claimed from JP2009170026A external-priority patent/JP5426263B2/en
Priority claimed from JP2009170014A external-priority patent/JP5364485B2/en
Priority claimed from JP2009170023A external-priority patent/JP5364486B2/en
Application filed by 本田技研工業株式会社 filed Critical 本田技研工業株式会社
Publication of WO2011010671A1 publication Critical patent/WO2011010671A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
    • B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements

Definitions

  • the present invention relates to a method for producing a metal bond grindstone suitable for plateau honing and a sintering furnace suitable for production of a metal bond grindstone.
  • FIG. 7 is an enlarged schematic view of a section of a cylinder that has been subjected to plateau honing.
  • An infinite number of plateaus (hills) 101 and adjacent plateaus 101 and 101 are formed on the surface of the cylinder 100 that has undergone plateau honing.
  • a trough 102 formed between the two.
  • the top surface 103 of the plateau 101 reduces the surface roughness to reduce wear, and maintains the lubrication between the top surface 103 and the piston with the oil accumulated in the valley 102. As a result, both slidability and lubricity can be achieved.
  • the present inventors pressure-sintered the metal bond grindstone material under the above-mentioned sintering conditions (500 ° C., 15 MPa). Although not explained in Patent Document 1 after sintering, a metal bond grindstone was obtained by stopping energization of the heater and cooling. The cooling rate at this time was 5.8 ° C./min.
  • the cross-sectional schematic diagram of the obtained metal bond grindstone is as follows.
  • FIG. 8 is a schematic cross-sectional view of a conventional metal bond grindstone.
  • a metal-based binder Mb as a base material
  • cobalt (Co) particles 111 in a metal-based binder Mb as a base material
  • abrasive grains 112 of about 5 ⁇ m
  • WS 2 tungsten disulfide
  • the filler added for the purpose of improving the mechanical properties is insufficiently dispersed. Therefore, the agglomerate 115 and the cobalt particles 111 that are fillers in the coarse crystals of the metal-based binder Mb that is the base material are mixed. It is generated by aggregation of tungsten sulfide particles 113. Such agglomerates 115 are more fragile than the surroundings.
  • FIG. 9 is an explanatory diagram of the operation of FIG. 8.
  • the agglomerate 115 dropped off from the surface, and a large pocket 116 having a diameter of about 30 ⁇ m was formed.
  • the holding power is reduced and the amount of grinding is reduced due to the progress of falling off of the abrasive grains, and the wear is rapidly increased due to the progress of falling off of the agglomerates, the conventional metal bond grindstone 110 has a short life.
  • the present inventors have found that the generation of the agglomerates 115 is caused by the structure of the sintering furnace.
  • One or more embodiments of the present invention provide a manufacturing technique that can manufacture a long-life metal bond wheel.
  • one or more embodiments of the present invention provide a sintering furnace that can suppress the generation of agglomerates.
  • the metal bond grindstone is baked by applying a press pressure to a material composed of abrasive grains, cobalt, tungsten disulfide, and a binder by hot pressing. It is manufactured by stopping heating and cooling the fired product.
  • the fired product may be cooled from the firing temperature to 600 ° C. at a temperature decreasing rate of 10 ° C./min or more.
  • cooling at 10 ° C./min or more is performed after the baking treatment.
  • the size of the agglomerates can be made sufficiently small, and the life of the grindstone can be extended.
  • the temperature lowering rate may be in the range of 10 to 20 ° C./min.
  • the raw material may be fired in a compressed inert gas atmosphere, and the fired product may be cooled while maintaining the pressure of the compressed inert gas.
  • the fired product is cooled in a compressed inert gas.
  • the inert gas When the inert gas is compressed, the density increases and the collision frequency between the gas molecules increases, so that the heat transfer property increases. That is, the compressed inert gas serves as a heat carrier that efficiently transfers the retained heat of the fired product to the water-cooled jacket.
  • the fired product When cooled at a high temperature-decreasing rate, generation of fragile agglomerates can be suppressed. As a result, the life of the grindstone can be extended.
  • a cooling rate of 10 ° C./min or more is obtained. If the cooling rate is 10 ° C./min or more, the generation of aggregates can be suppressed.
  • the pressure of the compressed inert gas may be 0.92 to 0.98 MPa as a gauge pressure.
  • the pressure resistance of the hot press is strongly required by the laws and regulations related to the high pressure vessel, and the hot press becomes expensive. According to the above method, by keeping the pressure of the compressed inert gas at 0.98 MPa, a high temperature reduction rate can be obtained while suppressing the price of the hot press. Moreover, if it is 0.92 Mpa or more, a high temperature-fall rate will be obtained.
  • a sintering furnace for producing a metal bond grindstone includes a cooling jacket and a furnace shell that can withstand an internal pressure of 0.98 MPa as a gauge pressure, and a gauge to the inside of the furnace shell.
  • An inert gas supply source for supplying an inert gas up to 0.98 MPa by pressure, a heater housed in the furnace shell for heating a metal bond grindstone material, and a ceramic disposed between the heater and the furnace shell A fiber heat insulating material, and a refrigerant supply device for supplying a refrigerant to the cooling jacket.
  • the fired product was cooled in a high-pressure inert gas.
  • the inert gas When the inert gas is compressed, the density increases and the collision frequency between the gas molecules increases, so that the heat transfer property increases.
  • the high-pressure inert gas serves as a heat carrier that efficiently transfers the heat retained in the fired product to the cooling jacket.
  • the heat insulating material interposed between the sintered product and the cooling jacket is a ceramic fiber that has better formability than graphite.
  • the sintered product can be rapidly cooled by making it thin-walled and thin-felt to increase the thermal conductivity as compared with the conventional graphite heat insulating material. When cooled at a high temperature-decreasing rate, generation of fragile agglomerates can be suppressed. As a result, the life of the grindstone can be extended.
  • the ceramic fiber heat insulating material may be a molded article or felt formed by compression molding ceramic fibers.
  • the molded product is formed by compression molding ceramic fibers, the density increases and the amount of heat storage increases slightly, but the shape maintainability increases and handling becomes easy.
  • the felt has a smaller density and a smaller amount of heat storage than the molded product, and therefore contributes to increasing the cooling rate of the sintered product.
  • the ceramic fiber heat insulating material may have a thickness of 12.5 mm or less.
  • the thickness of the heat insulating material is 50 mm with a general graphite heat insulating material, but in the above structure, ceramic fibers are used and the thickness is set to 12.5 mm or less. Since the thickness is 1 ⁇ 4 or less compared to the conventional graphite heat insulating material, the cooling rate of the sintered product is increased.
  • FIG. 6A is a correlation diagram between the size of the agglomerates and the grinding ratio.
  • FIG. 6B is a correlation diagram between the cooling rate and the size of the agglomerates. It is the schematic diagram which expanded the cross section of the cylinder to which the plateau honing process was performed. It is the schematic diagram which expanded the cross section of the conventional grindstone. It is the schematic diagram which expanded the cross section of the grindstone after use.
  • a hot press 10 (a sintering furnace 10 for manufacturing a metal bond grindstone (hereinafter referred to as a sintering furnace)) includes a water-cooled jacket 11 and can withstand an internal pressure of 0.98 MPa (G).
  • the heat insulation chamber 17 was formed of a ceramic fiber molded product having a thickness of 12.5 mm.
  • the heat insulation chamber 17 is composed of an example composed of graphite having a thickness of 50 mm, an example composed of a ceramic fiber molded product having a thickness of 10.0 mm, and a ceramic fiber felt having a thickness of 12.5 mm. An example will be described.
  • the lower part of the lower punch 13 is inserted into the cylinder 18, and when the pressure oil is sent to the cylinder 18 from the hydraulic pump 19, the lower punch 13 rises.
  • the oil pressure is detected by the pressure detection device 21.
  • Water cooling jacket 11 is supplied with water by water pump 22. This water is discharged to the chiller 23, the temperature is adjusted, and then returned to the water pump 22.
  • the graphite heater 16 is controlled by the furnace temperature control unit 25. That is, when the temperature detected by the furnace temperature detection device 26 is lower than the set value, the power supply amount to the graphite heater 16 is increased, and when the temperature is higher than the set value, the power supply amount to the graphite heater 16 is decreased. By doing so, it is possible to control the furnace temperature including the control of the rate of temperature increase.
  • the furnace shell 12 is provided with a furnace pressure detecting device 27 for detecting the pressure in the furnace and an exhaust / pressurizing tube 28, and an exhaust device 29 such as a vacuum pump and an ejector and an inert gas are provided in the tube 28.
  • a supply source 31 is connected.
  • the inert gas argon gas or nitrogen gas is easily available.
  • the exhaust device 29 and the inert gas supply source 31 are not used at the same time.
  • furnace pressure detecting device 27 separately for the pressure reduction and the pressure application, but here it is shared for convenience. The following experiment was performed using the hot press 10 described above.
  • ⁇ Material filling The material was filled in the die 14 of FIG. The maximum diameter of the die 14 is 120 mm.
  • Insulation room Ceramic fiber molded product with a thickness of 12.5mm ⁇
  • Exhaust In order to exclude the air in the furnace, the inside of the furnace is reduced to a pressure of 20 Pa (a) or less by the exhaust device 29 of FIG. This almost removes oxygen.
  • ⁇ Inert gas filling Argon gas is blown into the furnace from the inert gas supply source 31 of FIG. 1 to maintain the furnace pressure at a predetermined pressure.
  • ⁇ Press A press pressure of 30 MPa is applied to the material by the punches 13 and 15 in FIG.
  • Heating and heating rate Heat from the atmospheric temperature (25 ° C.) to the sintering temperature (740 ° C.) at a heating rate of 12.5 ° C./min. By holding at 740 ° C. for a certain time, the sintering process is performed.
  • ⁇ Heating stop The graphite heater 16 in FIG. 1 is stopped. This lowers the temperature in the furnace and the material. When the temperature is lowered, the pressure is monitored by the furnace pressure detection device 27 to control the exhaust device 29 and the inert gas supply source 31 so that the pressure of the inert gas in the furnace is maintained.
  • the cooling rate was as shown in the following figure. As shown in FIG. 2, when the pressure in the furnace is 0.01 MPa (G), the cooling rate is 11.9 ° C./min, 0.10 MPa (G) is 12.8 ° C./min, and 0.49 MPa (G). 16.0 ° C./min, 0.69 MPa (G) at 17.5 ° C./min, 0.80 MPa (G) at 18.7 ° C./min, 0.92 MPa (G) at 19.3 ° C./min there were.
  • Cooling means that heat is transferred (escapes) from the furnace center having a high temperature to the low outer periphery.
  • the transmitting substance that fulfills this mediation is the atmosphere. In other words, heat transfer is performed by collision of gas molecules.
  • the inside of the furnace is decompressed or replaced with gas, and the oxygen partial pressure is lowered before sintering. This is to prevent deterioration due to oxidation.
  • a reduced pressure atmosphere there are fewer substances (gas molecules) that transfer heat.
  • gas replacement the number of gas molecules hardly changes even if the type of gas changes. Therefore, the cooling rate is not improved in a general hot press atmosphere.
  • the temperature drop rate is improved by performing a hot press manufacturing method in a pressurized atmosphere in the furnace. Increasing the number of gaseous molecules by enclosing high pressure gas in the furnace. In other words, we succeeded in accelerating heat dissipation by increasing molecular collisions.
  • the cross section (schematic diagram) of the grindstone manufactured at a furnace pressure of 0.92 MPa (G) was as shown in the following figure.
  • the grindstone 40 includes abrasive grains 41, cobalt particles 42, tungsten disulfide particles 43, and a metal-based binder 44 that binds them, and also includes cobalt particles 42 and disulfides indicated by small black dots.
  • the tungsten particles 43 and the abrasive grains 41 were evenly dispersed.
  • FIG. 4 is an operation diagram of FIG. 3.
  • the tungsten disulfide particles 43 dropped from the surface, and fine pockets 47 were formed.
  • the cobalt particles 42 that improve the abrasion resistance of the abrasive grains remain in the grindstone and exhibit a grindstone wear inhibiting action. Further, the fine pocket 47 prevents the chips from accumulating on the front surface of the abrasive grains, and the dropped tungsten disulfide particles 43 serve as a solid lubricant to promote the discharge of the chips. Is prevented. By these actions, good machinability is maintained.
  • the size of the agglomerates could be reduced by cooling at a high cooling rate after sintering.
  • FIG. 5 (a) to FIG. 5 (e) are sketch diagrams of agglomerates magnified 3000 times.
  • FIG. 5A is a sketch diagram related to Experiment 1, and a fairly large aggregate 48 was observed.
  • the size L1 of the agglomerate 48 was 30 ⁇ m. This size was approximately equal to the average value of the number of agglomerates 48 distributed. Therefore, Table 1 lists 30 ⁇ m.
  • FIG. 5B is a sketch diagram related to Experiment 2, and the average size L2 of the aggregate 49 was 25 ⁇ m.
  • FIG. 5C is a sketch diagram related to Experiment 3, and the average size L3 of the aggregate 50 was 16 ⁇ m.
  • FIG. 5D is a sketch diagram related to Experiment 4, and the average size L4 of the aggregate 51 was 8 ⁇ m.
  • FIG. 5E is a sketch diagram related to Experiment 5, and the average size L5 of the aggregate 52 was 8 ⁇ m.
  • grinding volume a volume that is ground and removed by a predetermined volume.
  • wear volume a certain amount of volume is worn on the grindstone side.
  • (Grinding volume / wear volume) defined as grinding ratio. Since the grinding ratio represents the life of the grindstone itself, a grindstone with a large grinding ratio, that is, a grindstone with a small amount of wear of the grindstone and a large amount of workpiece grinding is desired.
  • a grinding ratio of 1000 can be obtained. Furthermore, if it is 10 ⁇ m or less, a grinding ratio of 2000 or more can be obtained. Therefore, a favorable grinding ratio can be obtained by setting the size of the agglomerates inevitably distributed on the grindstone to 15 ⁇ m or less, preferably 10 ⁇ m or less.
  • FIG. 6B is a graph showing the correlation between the temperature lowering rate and the size of the aggregate in Table 1.
  • the temperature decreasing rate is used to keep the average size of the aggregate at 16 ⁇ m. Needs to be 10 ° C./min or more. However, when the cooling rate in Experiment 4 is 18.6 ° C./min or more, the size of the aggregate hardly changes.
  • a preferable temperature decreasing rate is 10 to 20 ° C./min.
  • the graphite of 50 mm thickness shown in the section of the comparative example was replaced with a ceramic fiber molded product of 10.0 mm thickness in Experiment 07.
  • Other experimental conditions were the same as those in the comparative example.
  • the temperature drop rate of the comparative example was 10.8 ° C./min, but increased to 19.0 ° C./min in Experiment 07.
  • the 50 mm-thick graphite shown in the comparative example section was replaced with a 12.5 mm-thick ceramic fiber felt in Experiment 08.
  • Other experimental conditions were the same as those in the comparative example.
  • the temperature drop rate of the comparative example was 10.8 ° C./min, but increased to 26.4 ° C./min in Experiment 08.
  • the present invention is suitable for manufacturing a metal bond grindstone used for plateau honing.

Abstract

A metal-bonded grinding stone, which is produced by sintering a material comprising abrasive grains, cobalt, tungsten disulfide and a binder while applying a press pressure to the material by means of hot pressing, terminating the heating, and cooling the heated material.

Description

メタルボンド砥石の製造方法およびメタルボンド砥石製造用焼結炉Method for producing metal bond grindstone and sintering furnace for producing metal bond grindstone
　本発明は、プラトーホーニング加工に好適なメタルボンド砥石の製造方法、および、メタルボンド砥石の製造に適した焼結炉に関する。  The present invention relates to a method for producing a metal bond grindstone suitable for plateau honing and a sintering furnace suitable for production of a metal bond grindstone.
　近年、あらゆる分野において環境に対する取り組みがなされている。車両においても、燃費向上は取り組むべき重大な事項である。燃費向上対策の一つに、シリンダとピストンとの間の摩擦軽減がある。この摩擦軽減は、燃費向上だけでなく、運動性能の向上にも繋がる。 In recent years, environmental efforts have been made in all fields. Even in vehicles, improving fuel efficiency is an important issue to be addressed. One measure for improving fuel efficiency is to reduce friction between the cylinder and the piston. This friction reduction not only improves fuel consumption but also leads to improvement of exercise performance.
　上述の摩擦軽減を実現するには、プラトーホーニング工法が有効である。図７はプラトーホーニング加工が施されたシリンダの断面を拡大した模式図であり、プラトーホーニング加工が施されたシリンダ１００の表面には、無数のプラトー（丘）１０１と、隣り合うプラトー１０１、１０１の間に形成される谷１０２とが形成される。プラトー１０１の頂面１０３は面粗さを小さくして摩耗を低減させ、谷１０２に溜めたオイルで頂面１０３とピストンとの間の潤滑を維持する。この結果、摺動性と潤滑性を両立させることができる。 The plateau honing method is effective for realizing the above-mentioned friction reduction. FIG. 7 is an enlarged schematic view of a section of a cylinder that has been subjected to plateau honing. An infinite number of plateaus (hills) 101 and adjacent plateaus 101 and 101 are formed on the surface of the cylinder 100 that has undergone plateau honing. And a trough 102 formed between the two. The top surface 103 of the plateau 101 reduces the surface roughness to reduce wear, and maintains the lubrication between the top surface 103 and the piston with the oil accumulated in the valley 102. As a result, both slidability and lubricity can be achieved.
　以上に述べたプラトーホーニング加工に適した砥石として、メタルボンド砥石が提案されている（例えば、特許文献１参照。）。 As a grindstone suitable for the plateau honing process described above, a metal bond grindstone has been proposed (for example, see Patent Document 1).
　特許文献１の段落番号［００４９］に「製造条件は、硫酸バリウム（ＢａＳＯ４）を含む実施例の砥石の焼結温度５００℃及び成型圧力１５ＭＰａであった。いずれも調合した混合粉末を同時に加熱加圧（ホットプレス）して製作した。」の記載がある。 In paragraph No. [0049] of Patent Document 1, “Manufacturing conditions were a sintering temperature of 500 ° C. and a molding pressure of 15 MPa of the grinding wheel of the example containing barium sulfate (BaSO 4 ). "It was manufactured by pressing (hot pressing)."
　本発明者らは、上記焼結条件（５００℃、１５ＭＰａ）で、メタルボンド砥石素材を加圧焼結した。焼結後に、特許文献１には説明されていないが、ヒータへの通電を停止して冷却することでメタルボンド砥石を得た。このときの冷却速度は５．８℃／分であった。得られたメタルボンド砥石の断面模式図は次の通りである。 The present inventors pressure-sintered the metal bond grindstone material under the above-mentioned sintering conditions (500 ° C., 15 MPa). Although not explained in Patent Document 1 after sintering, a metal bond grindstone was obtained by stopping energization of the heater and cooling. The cooling rate at this time was 5.8 ° C./min. The cross-sectional schematic diagram of the obtained metal bond grindstone is as follows.
　図８は従来のメタルボンド砥石の断面模式図であり、このメタルボンド砥石１１０では、母材である金属系結合材Ｍｂ中に、コバルト（Ｃｏ）粒子１１１と、約５μｍの砥粒１１２と、二硫化タングステン（ＷＳ２）粒子１１３とを分散させることを基本とするが、これに約３０μｍの凝集塊１１５が含まれていることが判明した。 FIG. 8 is a schematic cross-sectional view of a conventional metal bond grindstone. In the metal bond grindstone 110, in a metal-based binder Mb as a base material, cobalt (Co) particles 111, abrasive grains 112 of about 5 μm, Although it is based on the dispersion of tungsten disulfide (WS 2 ) particles 113, it has been found that this contains an aggregate 115 of about 30 μm.
　この凝集塊１１５は、機械的特性の向上を目的に添加されるフィラーの分散が不十分であるため、母材である金属系結合材Ｍｂの粗大な結晶中にフィラーであるコバルト粒子１１１と二硫化タングステン粒子１１３とが凝集したことにより生成される。このような凝集塊１１５は、周囲に較べて脆弱である。 In this agglomerate 115, the filler added for the purpose of improving the mechanical properties is insufficiently dispersed. Therefore, the agglomerate 115 and the cobalt particles 111 that are fillers in the coarse crystals of the metal-based binder Mb that is the base material are mixed. It is generated by aggregation of tungsten sulfide particles 113. Such agglomerates 115 are more fragile than the surroundings.
　図９は図８の作用説明図であり、メタルボンド砥石１１０で暫く研削を行ったところ、凝集塊１１５が表面から脱落して、約３０μｍ径の大きなポケット１１６ができていた。このため保持力が低下して砥粒の脱落が進行することによる研削量の低下、および、凝集塊脱落の進行による摩耗の急増が発生するので、従来のメタルボンド砥石１１０は寿命が短いという問題があることが分かった。 FIG. 9 is an explanatory diagram of the operation of FIG. 8. When grinding was performed with the metal bond grindstone 110 for a while, the agglomerate 115 dropped off from the surface, and a large pocket 116 having a diameter of about 30 μm was formed. For this reason, since the holding power is reduced and the amount of grinding is reduced due to the progress of falling off of the abrasive grains, and the wear is rapidly increased due to the progress of falling off of the agglomerates, the conventional metal bond grindstone 110 has a short life. I found out that
　さらに、本発明者らは、凝集塊１１５の発生が、焼結炉の構造に起因することを突き止めた。 Furthermore, the present inventors have found that the generation of the agglomerates 115 is caused by the structure of the sintering furnace.
日本国特開２００８－２２９７９４公報Japanese Unexamined Patent Publication No. 2008-229794
　本発明の一以上の実施例は、高寿命のメタルボンド砥石を製造することができる製造技術を提供する。 One or more embodiments of the present invention provide a manufacturing technique that can manufacture a long-life metal bond wheel.
　また、本発明の一以上の実施例は、凝集塊の発生を抑えることができる焼結炉を提供する。 Also, one or more embodiments of the present invention provide a sintering furnace that can suppress the generation of agglomerates.
　本発明の一以上の実施例によれば、メタルボンド砥石は、ホットプレスにより、砥粒とコバルトと二硫化タングステンと結合材とからなる素材にプレス圧を付与しながら焼成処理して焼成品を得て、加熱を停止し前記焼成品を冷却すること、によって製造される。 According to one or more embodiments of the present invention, the metal bond grindstone is baked by applying a press pressure to a material composed of abrasive grains, cobalt, tungsten disulfide, and a binder by hot pressing. It is manufactured by stopping heating and cooling the fired product.
　前記焼成品は、焼成温度から６００℃まで１０℃／分以上の降温速度で冷却してもよい。 The fired product may be cooled from the firing temperature to 600 ° C. at a temperature decreasing rate of 10 ° C./min or more.
　上記の方法によれば、焼成処理後に、１０℃／分以上の冷却を行う。この冷却により、凝集塊の大きさを十分に小さくすることができ、砥石の寿命を延ばすことができる。 According to the above method, cooling at 10 ° C./min or more is performed after the baking treatment. By this cooling, the size of the agglomerates can be made sufficiently small, and the life of the grindstone can be extended.
上記の方法において、前記降温速度は、１０～２０℃／分の範囲であってもよい。 In the above method, the temperature lowering rate may be in the range of 10 to 20 ° C./min.
　降温速度を高めるほど設備的な負担が大きくなるが、降温速度を２０℃／分で留めることにより、コストの上昇を抑えることができる。 The higher the temperature drop rate, the greater the burden on the facility, but the cost rise can be suppressed by keeping the temperature drop rate at 20 ° C./min.
　また、上記の方法において、前記素材は、圧縮不活性ガス雰囲気中で焼成処理されてもよく、前記焼成品は、前記圧縮不活性ガスの圧力を維持しつつ冷却されてもよい。 In the above method, the raw material may be fired in a compressed inert gas atmosphere, and the fired product may be cooled while maintaining the pressure of the compressed inert gas.
　上記の方法によれば、焼成品は圧縮不活性ガス中で冷却される。不活性ガスは圧縮されると密度が大きくなりガス分子同士の衝突頻度が増すので、伝熱性が高まる。すなわち、圧縮不活性ガスは、焼成品の保有熱を、水冷ジャケットへ効率よく伝達する、熱キャリアの役割を果たす。高い降温速度で冷却すると、脆弱な凝集塊の発生を抑制することができる。結果、砥石の寿命を延ばすことができる。焼成品を圧縮不活性ガス中で冷却すると、１０℃／分以上の冷却速度が得られる。冷却速度が１０℃／分以上であれば、凝集塊の発生を抑えることができる。 According to the above method, the fired product is cooled in a compressed inert gas. When the inert gas is compressed, the density increases and the collision frequency between the gas molecules increases, so that the heat transfer property increases. That is, the compressed inert gas serves as a heat carrier that efficiently transfers the retained heat of the fired product to the water-cooled jacket. When cooled at a high temperature-decreasing rate, generation of fragile agglomerates can be suppressed. As a result, the life of the grindstone can be extended. When the fired product is cooled in a compressed inert gas, a cooling rate of 10 ° C./min or more is obtained. If the cooling rate is 10 ° C./min or more, the generation of aggregates can be suppressed.
　上記の方法において、前記圧縮不活性ガスの圧力は、ゲージ圧力で０．９２～０．９８ＭＰａであってもよい。 In the above method, the pressure of the compressed inert gas may be 0.92 to 0.98 MPa as a gauge pressure.
　０．９８ＭＰａを超えると高圧容器関連法令により、ホットプレスの耐圧性が強く求められ、ホットプレスが高価になる。上記の方法によれば、圧縮不活性ガスの圧力を０．９８ＭＰａに留めることにより、ホットプレスの価格を抑えつつ、高い降温速度が得られる。また、０．９２ＭＰａ以上であれば、高い降温速度が得られる。 If it exceeds 0.98 MPa, the pressure resistance of the hot press is strongly required by the laws and regulations related to the high pressure vessel, and the hot press becomes expensive. According to the above method, by keeping the pressure of the compressed inert gas at 0.98 MPa, a high temperature reduction rate can be obtained while suppressing the price of the hot press. Moreover, if it is 0.92 Mpa or more, a high temperature-fall rate will be obtained.
　また、本発明の一以上の実施例によれば、メタルボンド砥石製造用焼結炉は、冷却ジャケットを備えると共にゲージ圧で０．９８ＭＰａの内圧に耐える炉殻と、前記炉殻の内部へゲージ圧で０．９８ＭＰａまでの不活性ガスを供給する不活性ガス供給源と、前記炉殻に収納されメタルボンド砥石素材を加熱するヒータと、前記ヒータと前記炉殻との間に配置されるセラミックス繊維断熱材と、前記冷却ジャケットに冷媒を供給する冷媒供給装置と、を備える。 According to one or more embodiments of the present invention, a sintering furnace for producing a metal bond grindstone includes a cooling jacket and a furnace shell that can withstand an internal pressure of 0.98 MPa as a gauge pressure, and a gauge to the inside of the furnace shell. An inert gas supply source for supplying an inert gas up to 0.98 MPa by pressure, a heater housed in the furnace shell for heating a metal bond grindstone material, and a ceramic disposed between the heater and the furnace shell A fiber heat insulating material, and a refrigerant supply device for supplying a refrigerant to the cooling jacket.
　上記の構造によれば、焼成品を高圧不活性ガス中で冷却するようにした。不活性ガスは圧縮されると密度が大きくなりガス分子同士の衝突頻度が増すので、伝熱性が高まる。すなわち、高圧不活性ガスは、焼成品の保有熱を、冷却ジャケットへ効率よく伝達する、熱キャリアの役割を果たす。加えて、焼結品と冷却ジャケットとの間に介在する断熱材を黒鉛より成形性に優れるセラミックス繊維とした。薄肉成形化、薄肉フェルト化して従来の黒鉛断熱材に比して熱伝導性を高くすることにより、焼結品の急冷が可能となる。高い降温速度で冷却すると、脆弱な凝集塊の発生を抑制することができる。結果、砥石の寿命を延ばすことができる。 According to the above structure, the fired product was cooled in a high-pressure inert gas. When the inert gas is compressed, the density increases and the collision frequency between the gas molecules increases, so that the heat transfer property increases. In other words, the high-pressure inert gas serves as a heat carrier that efficiently transfers the heat retained in the fired product to the cooling jacket. In addition, the heat insulating material interposed between the sintered product and the cooling jacket is a ceramic fiber that has better formability than graphite. The sintered product can be rapidly cooled by making it thin-walled and thin-felt to increase the thermal conductivity as compared with the conventional graphite heat insulating material. When cooled at a high temperature-decreasing rate, generation of fragile agglomerates can be suppressed. As a result, the life of the grindstone can be extended.
　上記の構造において、前記セラミックス繊維断熱材は、セラミックス繊維を圧縮成形してなる成形品又はフェルトであってもよい。 In the above structure, the ceramic fiber heat insulating material may be a molded article or felt formed by compression molding ceramic fibers.
　成形品はセラミックス繊維を圧縮成形してなるため、密度が上がり蓄熱量がやや増加するが、形状の維持性が高まり、取扱いが容易になる。一方、フェルトは、成形品に比較して密度が小さく、蓄熱量が小さいため、焼結品の冷却速度を高めることに寄与する。 Since the molded product is formed by compression molding ceramic fibers, the density increases and the amount of heat storage increases slightly, but the shape maintainability increases and handling becomes easy. On the other hand, the felt has a smaller density and a smaller amount of heat storage than the molded product, and therefore contributes to increasing the cooling rate of the sintered product.
　前記セラミックス繊維断熱材は、厚さが１２．５ｍｍ以下であってもよい。 The ceramic fiber heat insulating material may have a thickness of 12.5 mm or less.
　断熱材の厚さは、一般の黒鉛断熱材で５０ｍｍとされるが、上記の構造ではセラミックス繊維を用い、厚さを１２．５ｍｍ以下とした。従来の黒鉛断熱材に比して厚みが１／４以下になるため、焼結品の冷却速度が高まる。 The thickness of the heat insulating material is 50 mm with a general graphite heat insulating material, but in the above structure, ceramic fibers are used and the thickness is set to 12.5 mm or less. Since the thickness is ¼ or less compared to the conventional graphite heat insulating material, the cooling rate of the sintered product is increased.
　その他の特徴および効果は、実施例の記載および添付のクレームより明白である。 Other features and effects will be apparent from the description of the embodiments and the appended claims.
本発明の典型的実施例に係るホットプレス（メタルボンド砥石製造用焼結炉）の断面図である。It is sectional drawing of the hot press (sintering furnace for metal bond grindstone manufacture) which concerns on the typical Example of this invention. 炉内圧力と降温速度の相関図である。It is a correlation diagram of a furnace pressure and a temperature drop rate. 砥石の断面を拡大した模式図である。It is the schematic diagram which expanded the cross section of the grindstone. 使用後の砥石の断面を拡大した模式図である。It is the schematic diagram which expanded the cross section of the grindstone after use. 図５（ａ）～図５（ｅ）は、実験１～実験５で得られた砥石における凝集塊の３０００倍に拡大したスケッチ図である。FIGS. 5 (a) to 5 (e) are sketch diagrams enlarged to 3000 times the agglomerates in the grindstones obtained in Experiments 1 to 5. FIG. 図６（ａ）は、凝集塊の大きさと研削比との相関図である。図６（ｂ）は、降温速度と凝集塊の大きさとの相関図である。FIG. 6A is a correlation diagram between the size of the agglomerates and the grinding ratio. FIG. 6B is a correlation diagram between the cooling rate and the size of the agglomerates. プラトーホーニング加工が施されたシリンダの断面を拡大した模式図である。It is the schematic diagram which expanded the cross section of the cylinder to which the plateau honing process was performed. 従来の砥石の断面を拡大した模式図である。It is the schematic diagram which expanded the cross section of the conventional grindstone. 使用後の砥石の断面を拡大した模式図である。It is the schematic diagram which expanded the cross section of the grindstone after use.
　本発明の典型的実施例を添付図に基づいて以下に説明する。なお、図面は符号の向きに見るものとする。また、圧力に関しては次の表記を採用する。減圧状態には、絶対真空をゼロとした絶対圧を使用し、単位の後に（ａ）を記す。加圧状態には、大気圧をゼロとしたケージ圧を使用し、単位の後に（Ｇ）を記す。 DETAILED DESCRIPTION Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals. The following notation is adopted for pressure. In the reduced pressure state, an absolute pressure with an absolute vacuum of zero is used, and (a) is written after the unit. For the pressurized state, a cage pressure with the atmospheric pressure set to zero is used, and (G) is written after the unit.
　図１に示されるように、ホットプレス１０（メタルボンド砥石製造用焼結炉１０（以下、焼結炉と記す。））は、水冷ジャケット１１を備え、内圧が０．９８ＭＰａ（Ｇ）まで耐える炉殻１２と、この炉殻１２の底から上向きに挿入された下部パンチ１３と、この下部パンチ１３に載せられる円筒状のダイ１４と、炉殻１２のトップから下向きに挿入され、ダイ１４に挿入される上部パンチ１５と、ダイ１４の周囲に配置される黒鉛ヒータ１６と、この黒鉛ヒータ１６を囲う断熱室１７とからなる。 As shown in FIG. 1, a hot press 10 (a sintering furnace 10 for manufacturing a metal bond grindstone (hereinafter referred to as a sintering furnace)) includes a water-cooled jacket 11 and can withstand an internal pressure of 0.98 MPa (G). A furnace shell 12, a lower punch 13 inserted upward from the bottom of the furnace shell 12, a cylindrical die 14 placed on the lower punch 13, and inserted downward from the top of the furnace shell 12, The upper punch 15 to be inserted, a graphite heater 16 disposed around the die 14, and a heat insulating chamber 17 surrounding the graphite heater 16.
　断熱室１７は、厚さ１２．５ｍｍのセラミックス繊維成形品で構成した。なお、実験の後段では、断熱室１７を、厚さ５０ｍｍの黒鉛で構成した例と、厚さ１０．０ｍｍのセラミックス繊維成形品で構成した例と、厚さ１２．５ｍｍのセラミックス繊維フェルトで構成した例を説明する。 The heat insulation chamber 17 was formed of a ceramic fiber molded product having a thickness of 12.5 mm. In the latter part of the experiment, the heat insulation chamber 17 is composed of an example composed of graphite having a thickness of 50 mm, an example composed of a ceramic fiber molded product having a thickness of 10.0 mm, and a ceramic fiber felt having a thickness of 12.5 mm. An example will be described.
　下部パンチ１３の下部はシリンダ１８に挿入され、このシリンダ１８へ油圧ポンプ１９から圧油が送られると下部パンチ１３は上昇する。油圧は圧力検出装置２１で検出する。水冷ジャケット１１へは、水ポンプ２２で給水される。この水はチラー２３に排出され、温度調節がなされた後、水ポンプ２２に戻される。 The lower part of the lower punch 13 is inserted into the cylinder 18, and when the pressure oil is sent to the cylinder 18 from the hydraulic pump 19, the lower punch 13 rises. The oil pressure is detected by the pressure detection device 21. Water cooling jacket 11 is supplied with water by water pump 22. This water is discharged to the chiller 23, the temperature is adjusted, and then returned to the water pump 22.
　黒鉛ヒータ１６は炉温制御部２５で制御される。すなわち、炉温検出装置２６で検出した温度が設定値より低い場合には、黒鉛ヒータ１６への給電量を増加し、温度が設定値より高い場合には、黒鉛ヒータ１６への給電量を減少させることにより、昇温速度の制御を含む炉温制御が可能となる。 The graphite heater 16 is controlled by the furnace temperature control unit 25. That is, when the temperature detected by the furnace temperature detection device 26 is lower than the set value, the power supply amount to the graphite heater 16 is increased, and when the temperature is higher than the set value, the power supply amount to the graphite heater 16 is decreased. By doing so, it is possible to control the furnace temperature including the control of the rate of temperature increase.
　また、炉殻１２には、炉内の圧力を検出する炉圧検出装置２７及び排気・加圧兼用の管２８が設けられ、この管２８に真空ポンプやエジェクターなどの排気装置２９及び不活性ガス供給源３１が接続されている。不活性ガスは、アルゴンガスや窒素ガスが入手容易である。ただし、排気装置２９と不活性ガス供給源３１とは同時に使用されることはない。 Further, the furnace shell 12 is provided with a furnace pressure detecting device 27 for detecting the pressure in the furnace and an exhaust / pressurizing tube 28, and an exhaust device 29 such as a vacuum pump and an ejector and an inert gas are provided in the tube 28. A supply source 31 is connected. As the inert gas, argon gas or nitrogen gas is easily available. However, the exhaust device 29 and the inert gas supply source 31 are not used at the same time.
　また、炉圧検出装置２７は減圧用と加圧用とは別々に設けることが望ましいが、ここでは便宜的に共用とした。以上に説明したホットプレス１０を用いて次に述べる実験を行った。 Also, it is desirable to provide the furnace pressure detecting device 27 separately for the pressure reduction and the pressure application, but here it is shared for convenience. The following experiment was performed using the hot press 10 described above.
（実験例）
　本発明の典型的実施例に係る実験例を以下に述べる。なお、本発明は実験例に限定されるものではない。
○素材：
　砥粒（平均粒径５μｍ）：８．７５体積％
　コバルト：５６体積％
　二硫化タングステン：５．２５体積％
　結合材（りん青銅）：３０体積％ (Experimental example)
An experimental example according to an exemplary embodiment of the present invention will be described below. Note that the present invention is not limited to experimental examples.
○ Material:
Abrasive grains (average grain size 5 μm): 8.75 vol%
Cobalt: 56% by volume
Tungsten disulfide: 5.25% by volume
Binder (phosphor bronze): 30% by volume
○素材充填：
　上記素材を、図１のダイ１４に充填した。なお、ダイ１４の最大径は１２０ｍｍである。
○断熱室：
　厚さ１２．５ｍｍのセラミックス繊維成形品
○排気：
　炉内の空気を排除するために、図１の排気装置２９により、炉内を２０Ｐａ（ａ）又はそれ以下の圧力に減圧する。これで、酸素は殆ど除去される。 ○ Material filling:
The material was filled in the die 14 of FIG. The maximum diameter of the die 14 is 120 mm.
○ Insulation room:
Ceramic fiber molded product with a thickness of 12.5mm ○ Exhaust:
In order to exclude the air in the furnace, the inside of the furnace is reduced to a pressure of 20 Pa (a) or less by the exhaust device 29 of FIG. This almost removes oxygen.
○不活性ガス充填：
　図１の不活性ガス供給源３１からアルゴンガスを炉内へ吹き込み、炉圧を所定の圧力に維持する。
○プレス：
　図１のパンチ１３、１５により、素材に３０ＭＰａのプレス圧を付与する。 ○ Inert gas filling:
Argon gas is blown into the furnace from the inert gas supply source 31 of FIG. 1 to maintain the furnace pressure at a predetermined pressure.
○ Press:
A press pressure of 30 MPa is applied to the material by the punches 13 and 15 in FIG.
○加熱及び昇温速度：
　大気温度（２５℃）から焼結温度（７４０℃）まで、１２．５℃／分の昇温速度で加熱する。７４０℃で一定時間保持することにより、焼結処理がなされる。
○加熱停止：
　図１の黒鉛ヒータ１６を止める。これで、炉内及び素材の温度は下がる。降温の際には、炉内の不活性ガスの圧力が維持されるように、炉圧検出装置２７で圧力を監視して排気装置２９、及び不活性ガス供給源３１を制御する。 ○ Heating and heating rate:
Heat from the atmospheric temperature (25 ° C.) to the sintering temperature (740 ° C.) at a heating rate of 12.5 ° C./min. By holding at 740 ° C. for a certain time, the sintering process is performed.
○ Heating stop:
The graphite heater 16 in FIG. 1 is stopped. This lowers the temperature in the furnace and the material. When the temperature is lowered, the pressure is monitored by the furnace pressure detection device 27 to control the exhaust device 29 and the inert gas supply source 31 so that the pressure of the inert gas in the furnace is maintained.
　降温速度は、次図に示す通りであった。
　図２に示すように、炉内圧力が０．０１ＭＰａ（Ｇ）では、降温速度は１１．９℃／分、０．１０ＭＰａ（Ｇ）で１２．８℃／分、０．４９ＭＰａ（Ｇ）で１６．０℃／分、０．６９ＭＰａ（Ｇ）で１７．５℃／分、０．８０ＭＰａ（Ｇ）で１８．７℃／分、０．９２ＭＰａ（Ｇ）で、１９．３℃／分であった。なお、降温速度は７４０℃～６００℃までの所要時間を計測し、（７４０－６００）／所要時間＝降温速度の計算により求めた。 The cooling rate was as shown in the following figure.
As shown in FIG. 2, when the pressure in the furnace is 0.01 MPa (G), the cooling rate is 11.9 ° C./min, 0.10 MPa (G) is 12.8 ° C./min, and 0.49 MPa (G). 16.0 ° C./min, 0.69 MPa (G) at 17.5 ° C./min, 0.80 MPa (G) at 18.7 ° C./min, 0.92 MPa (G) at 19.3 ° C./min there were. The temperature drop rate was obtained by measuring the required time from 740 ° C. to 600 ° C. and calculating (740−600) / required time = temperature drop rate.
　降温速度の差異は、次のように説明することができる。冷却とは温度が高い炉中心部から低い外周部に熱が伝わる（逃げる）事である。この仲介を果たす伝達物質が雰囲気となる。言い換えれば、熱の伝達は気体分子の衝突で行われる。 The difference in cooling rate can be explained as follows. Cooling means that heat is transferred (escapes) from the furnace center having a high temperature to the low outer periphery. The transmitting substance that fulfills this mediation is the atmosphere. In other words, heat transfer is performed by collision of gas molecules.
　一般的なホットプレス製法は、炉内を減圧もしくはガス置換を行い、酸素分圧を下げてから焼結する。これは、酸化による劣化を防ぐ為である。減圧雰囲気では、熱を伝達する物質（気体分子）が少なくなる。また、ガス置換についても、ガスの種類が変わっても気体分子数はほとんど変わらない。よって、一般的なホットプレスの雰囲気では降温速度は向上しない。 In general hot press manufacturing method, the inside of the furnace is decompressed or replaced with gas, and the oxygen partial pressure is lowered before sintering. This is to prevent deterioration due to oxidation. In a reduced pressure atmosphere, there are fewer substances (gas molecules) that transfer heat. In addition, regarding gas replacement, the number of gas molecules hardly changes even if the type of gas changes. Therefore, the cooling rate is not improved in a general hot press atmosphere.
　本発明の典型的実施例では、炉内の雰囲気を加圧状態でホットプレス製法を行うことにより、降温速度を向上させるものである。高圧ガスを炉に封入する事により気体の分子の数を増やす。すなわち、分子の衝突を増やして放熱を加速することに成功した。 In a typical embodiment of the present invention, the temperature drop rate is improved by performing a hot press manufacturing method in a pressurized atmosphere in the furnace. Increasing the number of gaseous molecules by enclosing high pressure gas in the furnace. In other words, we succeeded in accelerating heat dissipation by increasing molecular collisions.
○０．９２ＭＰａ（Ｇ）での評価：
　炉内圧力が０．９２ＭＰａ（Ｇ）で製作した砥石の断面（模式図）は次図の通りであった。図３に示すように、砥石４０は、砥粒４１とコバルト粒子４２と二硫化タングステン粒子４３と、これらを結合する金属系結合材４４とからなると共に、小さな黒点で示すコバルト粒子４２と二硫化タングステン粒子４３と砥粒４１とが均等に分散されていた。 ○ Evaluation at 0.92 MPa (G):
The cross section (schematic diagram) of the grindstone manufactured at a furnace pressure of 0.92 MPa (G) was as shown in the following figure. As shown in FIG. 3, the grindstone 40 includes abrasive grains 41, cobalt particles 42, tungsten disulfide particles 43, and a metal-based binder 44 that binds them, and also includes cobalt particles 42 and disulfides indicated by small black dots. The tungsten particles 43 and the abrasive grains 41 were evenly dispersed.
　図４は図３の作用図であり、このような砥石４０で研削を行ったところ、表面から二硫化タングステン粒子４３が脱落し、微細なポケット４７ができた。 FIG. 4 is an operation diagram of FIG. 3. When grinding was performed with such a grindstone 40, the tungsten disulfide particles 43 dropped from the surface, and fine pockets 47 were formed.
　すなわち、砥粒の耐摩耗性を向上させるコバルト粒子４２は砥石内にとどまって砥石摩耗抑止作用を発揮する。さらに、微細ポケット４７は切粉の砥粒前面への堆積を防止し、脱落した二硫化タングステン粒子４３が固体潤滑剤の役割を果たして切粉の排出性を促進するため、切粉による目詰まりが防止される。これらの作用により、良好な切削性が維持される。 That is, the cobalt particles 42 that improve the abrasion resistance of the abrasive grains remain in the grindstone and exhibit a grindstone wear inhibiting action. Further, the fine pocket 47 prevents the chips from accumulating on the front surface of the abrasive grains, and the dropped tungsten disulfide particles 43 serve as a solid lubricant to promote the discharge of the chips. Is prevented. By these actions, good machinability is maintained.
○大気圧（０．０１ＭＰａ（Ｇ））での評価：
　一方、炉内圧力が０．０１ＭＰａ（Ｇ）で製作した砥石の断面（模式図）は、従来の技術で述べた図８とほぼ同一であり、図９のような問題点を有する。 ○ Evaluation at atmospheric pressure (0.01 MPa (G)):
On the other hand, the cross-section (schematic diagram) of the grindstone manufactured at a furnace pressure of 0.01 MPa (G) is almost the same as FIG. 8 described in the prior art, and has the problem as shown in FIG.
　本発明の典型的実施例のように、焼結後に、高降温速度で冷却することで、凝集塊（図８、符号１１５）の大きさを小さくすることができた。 As in a typical example of the present invention, the size of the agglomerates (FIG. 8, reference numeral 115) could be reduced by cooling at a high cooling rate after sintering.
　以上に述べたように、降温速度の増加に比例して、凝集塊の大きさを小さくすることができることが分かった。そこで、次に降温速度と凝集塊の大きさの相関を調べる追加実験（第１追加実験）を行った。 As described above, it has been found that the size of the agglomerates can be reduced in proportion to the increase in the cooling rate. Therefore, an additional experiment (first additional experiment) was conducted to examine the correlation between the cooling rate and the size of the agglomerates.
（第１追加実験）
○実験１～５：
　表１に示すように、降温速度を５．８～２６．４℃／分として、上記（実験例）の項で示した実験条件で、砥石を製作した。ただし、図２では降温速度は、１１．９～１９．３℃／分であった。しかし、サイズの大きなダイを使用することで降温速度を下げることができ、サイズの小さなダイを使用することで降温速度を上げることができる。加えて、断熱室１７を構成する断熱材の厚さを変え、種類を替えることでも降温速度が調整できる。このような処置を施すことにより、５．８～２６．４℃／分の降温速度を実現した。 (First additional experiment)
○ Experiments 1 to 5:
As shown in Table 1, a grindstone was manufactured under the experimental conditions shown in the above (Experimental Example) with a temperature drop rate of 5.8 to 26.4 ° C./min. However, in FIG. 2, the temperature lowering rate was 11.9 to 19.3 ° C./min. However, the cooling rate can be lowered by using a large die, and the cooling rate can be increased by using a small die. In addition, the temperature lowering rate can be adjusted by changing the thickness of the heat insulating material constituting the heat insulating chamber 17 and changing the type. By performing such treatment, a temperature drop rate of 5.8 to 26.4 ° C./min was realized.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　得られた砥石の最表面をＳＥＭにて３０００倍の顕微鏡写真を観察した。図５（ａ）～図５（ｅ）は３０００倍に拡大した凝集塊のスケッチ図である。図５（ａ）は実験１に係るスケッチ図であり、かなり大きな凝集塊４８が認められた。この凝集塊４８の大きさＬ１は３０μｍであった。この大きさは分布している多数の凝集塊４８の大きさの平均値にほぼ等しかった。そこで、表１に３０μｍを記載した。 The outermost surface of the obtained grindstone was observed with a SEM at a magnification of 3000 times. FIG. 5 (a) to FIG. 5 (e) are sketch diagrams of agglomerates magnified 3000 times. FIG. 5A is a sketch diagram related to Experiment 1, and a fairly large aggregate 48 was observed. The size L1 of the agglomerate 48 was 30 μm. This size was approximately equal to the average value of the number of agglomerates 48 distributed. Therefore, Table 1 lists 30 μm.
　図５（ｂ）は実験２に係るスケッチ図であり、凝集塊４９の平均的大きさＬ２は２５μｍであった。図５（ｃ）は実験３に係るスケッチ図であり、凝集塊５０の平均的大きさＬ３は１６μｍであった。図５（ｄ）は実験４に係るスケッチ図であり、凝集塊５１の平均的大きさＬ４は８μｍであった。図５（ｅ）は実験５に係るスケッチ図であり、凝集塊５２の平均的大きさＬ５は８μｍであった。 FIG. 5B is a sketch diagram related to Experiment 2, and the average size L2 of the aggregate 49 was 25 μm. FIG. 5C is a sketch diagram related to Experiment 3, and the average size L3 of the aggregate 50 was 16 μm. FIG. 5D is a sketch diagram related to Experiment 4, and the average size L4 of the aggregate 51 was 8 μm. FIG. 5E is a sketch diagram related to Experiment 5, and the average size L5 of the aggregate 52 was 8 μm.
　ところで、砥石でワークを研削した場合に、ワークは所定の体積だけ研削除去される。この体積を研削体積と呼ぶ。また、砥石側もある程度の体積が摩耗する。この体積を摩耗体積と呼ぶ。（研削体積／摩耗体積）＝研削比と定義する。研削比は砥石の寿命そのものを表すので、研削比の大きな砥石、すなわち、砥石の摩耗量が少なく、ワークの研削量が大きい砥石が望まれる。 By the way, when a workpiece is ground with a grindstone, the workpiece is ground and removed by a predetermined volume. This volume is called the grinding volume. Moreover, a certain amount of volume is worn on the grindstone side. This volume is called the wear volume. (Grinding volume / wear volume) = defined as grinding ratio. Since the grinding ratio represents the life of the grindstone itself, a grindstone with a large grinding ratio, that is, a grindstone with a small amount of wear of the grindstone and a large amount of workpiece grinding is desired.
　実験１～５での砥石を用いて研削比を調べたところ、表１に示す値が得られた。表１に記載されている凝集塊の大きさと研削比との相関をグラフ化する。図６（ａ）に示すように、凝集塊の大きさが小さいほど研削比が大きくなることが分かる。そして、グラフは横軸目盛りで１６、すなわち凝集塊の大きさが１６μｍに特異点があり、凝集塊の大きさが１６μｍ以下であれば、高い研削比が得られることが分かった。 When the grinding ratio was examined using the grindstone in Experiments 1 to 5, the values shown in Table 1 were obtained. The correlation between the size of the agglomerates described in Table 1 and the grinding ratio is graphed. As shown in FIG. 6A, it can be seen that the grinding ratio increases as the size of the agglomerates decreases. The graph shows that the horizontal axis scale is 16, that is, the size of the agglomerates has a specific point of 16 μm, and if the size of the agglomerates is 16 μm or less, a high grinding ratio can be obtained.
　１μｍ余裕を見た１５μｍ以下であれば、研削比１０００が得られる。さらに、１０μｍ以下であれば、研削比２０００以上が得られる。したがって、砥石に不可避的に分布する凝集塊の大きさは、１５μｍ以下、好ましくは１０μｍ以下にすることで、良好な研削比が得られる。 If it is 15 μm or less with a margin of 1 μm, a grinding ratio of 1000 can be obtained. Furthermore, if it is 10 μm or less, a grinding ratio of 2000 or more can be obtained. Therefore, a favorable grinding ratio can be obtained by setting the size of the agglomerates inevitably distributed on the grindstone to 15 μm or less, preferably 10 μm or less.
　なお、図６（ｂ）は表１の降温速度と凝集塊の大きさの相関をグラフ化したものであり、破線で示すように、凝集塊の平均的大きさを１６μｍに留めるには降温速度は１０℃／分以上にする必要がある。ただし、実験４での降温速度１８．６℃／分以上では、凝集塊の大きさは殆ど変化しない。降温速度を高めるには設備的に負担を強いるために、２０℃／分を上限とすることが望まれる。従って、好ましい降温速度は１０～２０℃／分となる。 FIG. 6B is a graph showing the correlation between the temperature lowering rate and the size of the aggregate in Table 1. As shown by the broken line, the temperature decreasing rate is used to keep the average size of the aggregate at 16 μm. Needs to be 10 ° C./min or more. However, when the cooling rate in Experiment 4 is 18.6 ° C./min or more, the size of the aggregate hardly changes. In order to increase the temperature lowering rate, it is desirable to set the upper limit at 20 ° C./min in order to impose a burden on equipment. Therefore, a preferable temperature decreasing rate is 10 to 20 ° C./min.
　なお、不活性ガス雰囲気において、高降温速度を得るには、焼結炉内の断熱室の断熱性能を下げることが有効である。この知見に基づいて、第２追加実験を行った。 In order to obtain a high cooling rate in an inert gas atmosphere, it is effective to lower the heat insulation performance of the heat insulation chamber in the sintering furnace. Based on this finding, a second additional experiment was conducted.
（第２追加実験）
　追加実験の内容を、表２に示す。
Figure JPOXMLDOC01-appb-T000002
 (Second additional experiment)
The contents of the additional experiment are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
　比較例の項に示した５０ｍｍ厚さの黒鉛を、実験０６では、１２．５ｍｍ厚さのセラミックス繊維成形品に替えた。他の実験条件は比較例と同一とした。結果、比較例の降温速度が１０．８℃／分であったものが、実験０６では、１８．６℃／分に高まった。 In the experiment 06, the graphite having a thickness of 50 mm shown in the comparative example was replaced with a ceramic fiber molded product having a thickness of 12.5 mm. Other experimental conditions were the same as those in the comparative example. As a result, the temperature drop rate of the comparative example was 10.8 ° C./min, but increased to 18.6 ° C./min in Experiment 06.
　さらに、比較例の項に示した５０ｍｍ厚さの黒鉛を、実験０７では、１０．０ｍｍ厚さのセラミックス繊維成形品に替えた。他の実験条件は比較例と同一とした。結果、比較例の降温速度が１０．８℃／分であったものが、実験０７では、１９．０℃／分に高まった。 Furthermore, the graphite of 50 mm thickness shown in the section of the comparative example was replaced with a ceramic fiber molded product of 10.0 mm thickness in Experiment 07. Other experimental conditions were the same as those in the comparative example. As a result, the temperature drop rate of the comparative example was 10.8 ° C./min, but increased to 19.0 ° C./min in Experiment 07.
　また、比較例の項に示した５０ｍｍ厚さの黒鉛を、実験０８では、１２．５ｍｍ厚さのセラミックス繊維フェルトに替えた。他の実験条件は比較例と同一とした。結果、比較例の降温速度が１０．８℃／分であったものが、実験０８では、２６．４℃／分に高まった。 In addition, the 50 mm-thick graphite shown in the comparative example section was replaced with a 12.5 mm-thick ceramic fiber felt in Experiment 08. Other experimental conditions were the same as those in the comparative example. As a result, the temperature drop rate of the comparative example was 10.8 ° C./min, but increased to 26.4 ° C./min in Experiment 08.
　実験結果を、研削比で比較すると、実験０６、０７、０８共に、比較例の２倍以上の研削比が得られた。  When the experimental results were compared by the grinding ratio, the grinding ratio more than twice that of the comparative example was obtained in each of Experiments 06, 07, and 08.
　本発明は、プラトーホーニング加工に用いるメタルボンド砥石の製造に好適である。  The present invention is suitable for manufacturing a metal bond grindstone used for plateau honing.
１０…ホットプレス（メタルボンド砥石製造用焼結炉）、１１…水冷ジャケット、２２…冷媒供給装置としての水ポンプ、３１…不活性ガス供給源、４０…砥石、４１…砥粒、４２…コバルト粒子、４３…二硫化タングステン粒子、４４…結合材、４８～５２…凝集塊、Ｌ１～Ｌ５…凝集塊の大きさ（平均的大きさ） DESCRIPTION OF SYMBOLS 10 ... Hot press (sintering furnace for metal bond grindstone manufacture), 11 ... Water cooling jacket, 22 ... Water pump as refrigerant supply device, 31 ... Inert gas supply source, 40 ... Grinding stone, 41 ... Abrasive grain, 42 ... Cobalt Particles 43 ... Tungsten disulfide particles 44 ... Binder 48-52 ... Agglomerate L1-L5 ... Agglomerate size (average size)

Claims (8)

  1. 　ホットプレスにより、砥粒と、コバルトと、二硫化タングステンと、結合材と、からなる素材にプレス圧を付与しながら、焼成処理して、焼成品を得て、
    　加熱を停止し、前記焼成品を冷却することで砥石を得る、
    　メタルボンド砥石の製造方法。     By applying a press pressure to a material composed of abrasive grains, cobalt, tungsten disulfide, and a binder by hot pressing, a baking treatment is performed to obtain a fired product,
    Stop the heating and cool the fired product to obtain a grindstone.
    Manufacturing method of metal bond grindstone.
  2. 　前記焼成品は、焼成温度から６００℃まで１０℃／分以上の降温速度で冷却される、請求項１に記載のメタルボンド砥石の製造方法。 The method for producing a metal bond grindstone according to claim 1, wherein the fired product is cooled from a firing temperature to 600 ° C at a temperature lowering rate of 10 ° C / min or more.
  3. 　前記降温速度は、１０～２０℃／分の範囲である、請求項２に記載のメタルボンド砥石の製造方法。 The method for producing a metal bond grindstone according to claim 2, wherein the temperature lowering rate is in the range of 10 to 20 ° C / min.
  4. 　前記素材は、圧縮不活性ガス雰囲気中で焼成処理され、
    　前記焼成品は、前記圧縮不活性ガスの圧力を維持しつつ冷却される、
    　請求項１～３のいずれか一項に記載のメタルボンド砥石の製造方法。     The material is fired in a compressed inert gas atmosphere,
    The fired product is cooled while maintaining the pressure of the compressed inert gas.
    The method for producing a metal bond grindstone according to any one of claims 1 to 3.
  5. 　前記圧縮不活性ガスの圧力は、ゲージ圧力で０．９２～０．９８ＭＰａである、請求項４に記載のメタルボンド砥石の製造方法。 The method for producing a metal bond grindstone according to claim 4, wherein the pressure of the compressed inert gas is 0.92 to 0.98 MPa in gauge pressure.
  6. 　冷却ジャケットを備えると共にゲージ圧で０．９８ＭＰａの内圧に耐える炉殻と、
    　前記炉殻の内部へゲージ圧で０．９８ＭＰａまでの不活性ガスを供給する不活性ガス供給源と、
    　前記炉殻に収納されメタルボンド砥石素材を加熱するヒータと、
    　前記ヒータと前記炉殻との間に配置されるセラミックス繊維断熱材と、
    　前記冷却ジャケットに冷媒を供給する冷媒供給装置と、
    　を具備する、
    　メタルボンド砥石製造用焼結炉。     A furnace shell provided with a cooling jacket and capable of withstanding an internal pressure of 0.98 MPa by gauge pressure;
    An inert gas supply source for supplying an inert gas up to 0.98 MPa by gauge pressure into the furnace shell;
    A heater housed in the furnace shell for heating the metal bond grindstone material;
    A ceramic fiber heat insulating material disposed between the heater and the furnace shell;
    A refrigerant supply device for supplying a refrigerant to the cooling jacket;
    Comprising
    Sintering furnace for metal bond grinding wheel production.
  7. 　前記セラミックス繊維断熱材は、セラミックス繊維を圧縮成形してなる成形品又はフェルトである、請求項６に記載のメタルボンド砥石製造用焼結炉。 The sintering furnace for producing a metal bond grindstone according to claim 6, wherein the ceramic fiber heat insulating material is a molded article or felt formed by compression molding ceramic fibers.
  8. 　前記セラミックス繊維断熱材は、厚さが１２．５ｍｍ以下である、請求項７に記載のメタルボンド砥石製造用焼結炉。 The sintering furnace for producing a metal bond grindstone according to claim 7, wherein the ceramic fiber heat insulating material has a thickness of 12.5 mm or less.
PCT/JP2010/062258 2009-07-21 2010-07-21 Process for production of metal-bonded grinding stone, and sintering furnace for production of metal-bonded grinding stone WO2011010671A1 (en)

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JPS5954098U (en) * 1982-10-04 1984-04-09 株式会社神戸製鋼所 High efficiency hot isostatic pressing equipment
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JPH10128668A (en) * 1996-10-29 1998-05-19 Alps Electric Co Ltd Super-abrasive grain grinding wheel and its manufacture
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JPS58217271A (en) * 1982-06-11 1983-12-17 Nippon Kogaku Kk <Nikon> Fine grinding wheel
JPS5954098U (en) * 1982-10-04 1984-04-09 株式会社神戸製鋼所 High efficiency hot isostatic pressing equipment
JPH0313506A (en) * 1989-06-08 1991-01-22 Kobe Steel Ltd Apparatus and method for working under hot isostatic pressure
JPH1071569A (en) * 1996-05-01 1998-03-17 Osaka Diamond Ind Co Ltd Super abrasive grain sintered member, tool using it, and its manufacture
JPH10128668A (en) * 1996-10-29 1998-05-19 Alps Electric Co Ltd Super-abrasive grain grinding wheel and its manufacture
JP2002046070A (en) * 2000-08-07 2002-02-12 Toshiba Mach Co Ltd Method and device for manufacturing grinding wheel
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Publication number Priority date Publication date Assignee Title
CN109764674A (en) * 2019-01-27 2019-05-17 天津大学 High temperature tunnel furnace for powder body material sinter molding

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