JP3770712B2 - Super abrasive wheel and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a superabrasive wheel used for cutting and cutting brittle materials such as stone, concrete, ceramics, and refractory bricks, and a method for manufacturing the same.
[0002]
[Prior art]
Super-abrasive wheels with an abrasive layer formed on the surface of a base metal by simultaneous molding are used for cutting or cutting brittle materials such as stone, concrete, ceramics, refractory bricks, etc. In the superabrasive wheel, the bonding force between the base metal and the abrasive layer is the most important for safety.
[0003]
Conventionally, in order to satisfy this requirement, copper plating is applied to the surface of an iron base metal, and copper having the same quality as the plating component is used as a bonding material for the abrasive layer. As a result, when the abrasive layer is sintered and formed on the base metal surface, the copper of the plating component and the copper constituting the abrasive layer are interdiffused, and the abrasive layer and the plated layer are firmly bonded by mutual diffusion. It becomes possible to do. Further, the base metal and the copper plating layer are firmly bonded by mechanical bonding.
[0004]
As such a technique, for example, in Japanese Patent Application Laid-Open No. 63-22274, a copper-plated iron thin plate is used as an underlayer, and a diamond layer is used together with metal powders such as copper, tin, zinc and nickel. A method of sintering is disclosed.
[0005]
However, copper plating on the surface of the base metal not only increases the number of manufacturing steps, but also due to the problem of plating processing that the base metal surface must be covered with an insulator on the part that is not plated, abrasive grains Other than the layer forming portion, the entire surface must be plated, which is a major impediment to cost reduction.
[0006]
In addition, Japanese Utility Model Laid-Open No. 55-142258 discloses a segment chip in which a large number of concave portions are provided on the protrusions on the outer peripheral surface of the base metal in order to improve the bonding strength between the base metal and the abrasive layer. Although a diamond grindstone in which the bonding strength is mechanically increased is described, it is difficult to adopt such a recessed portion as a practical manufacturing method because of the high processing cost.
[0007]
[Problems to be solved by the invention]
The problem to be solved in the present invention is to provide a superabrasive wheel that reduces the manufacturing cost and is excellent in the bonding force between the base metal and the abrasive layer.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have conducted intensive research on a method for obtaining a bonding force equal to or higher than that without applying copper plating. As a result, nickel and tin that have been conventionally used as bond materials are specified. It has been found that this can be solved by using the ratio, and the present invention has been completed.
[0009]
That is, the superabrasive wheel of the present invention forms an abrasive layer by sintering a mixture of superabrasives such as diamond and CBN and a metal powder as a bonding material, and the abrasive layer. Is a superabrasive wheel that directly joins the iron base metal surface without a plating layer, and uses at least nickel and tin as the metal powder, and the amount of tin with respect to the nickel is 15 to 35 wt. % Range.
[0010]
Here, when nickel is used as a bond material, it has characteristics that it has high heat resistance and does not burn, and has high strength and high ductility, so that the strength of the abrasive layer is increased. On the other hand, it has high strength and is difficult to wear, and therefore has the characteristic of making it difficult for the abrasive grains to self-act.
[0011]
In contrast, tin is unsuitable as the main material of the bond material because it has low heat resistance and bond burns, and the strength of the abrasive layer is low due to low strength and low ductility. It is used as. On the other hand, since it has low strength and easily wears, it has a feature of promoting the self-generated action of the abrasive grains.
[0012]
As a result of the experiment, the inventors have determined that the sintering temperature of the abrasive layer is not manifested by the disadvantage of tin that the heat resistance is low and the strength is low by setting the tin to 15 to 35% by weight with respect to the amount of nickel. It is fluidized at a low temperature of 700 to 1000 ° C. to cover the periphery of nickel, and as a result, nickel can be activated to penetrate deep into the iron base metal and have a nickel diffusion region over 10 μm or more. I found out. In addition, as materials other than nickel and tin, copper, cobalt, iron, and the like can be suitably used.
[0013]
Here, when the amount of tin is less than 15% by weight with respect to the amount of nickel, the amount of tin is insufficient, and the nickel diffusion region to the base metal becomes narrow without covering the periphery of nickel. Also, the bond strength is too high to make it difficult for the abrasive grains to self-generate. On the other hand, if it exceeds 35% by weight, the nickel diffusion region increases slightly, but the strength becomes insufficient, so the above range is desirable.
[0014]
Further, the nickel content is desirably 15% by weight or more, more preferably 40% by weight or more of the entire bond material. When the nickel content is less than 15% by weight, even if the tin content is within the above range, the nickel content is insufficient, the nickel diffusion region becomes narrow, and the bonding strength between the abrasive layer and the base metal becomes low. Lower. If it is 15% by weight or more, a diffusion region of 10 μm or more is obtained, and if it is 40% by weight or more, the diffusion region and the bonding strength are stabilized at a high level.
[0015]
FIG. 1 is a schematic diagram explaining the activation of nickel by melting of tin, (a) is a state when pressurized at room temperature, (b) is a state when pressurized at 300 ° C., (c) is Each state when pressurized at 700 ° C. is shown. In addition, although this description describes what contains copper as materials other than nickel and tin, the same tendency was seen also in cobalt and iron instead of copper.
[0016]
In FIG. 1, 1 is an iron base metal, 2 is an abrasive layer, 3 is nickel powder, 4 is tin powder, 5 is copper powder, and diamond abrasive grains in the abrasive layer 2 are not shown. ing. As shown in FIG. 5A, in a state where the pressure is applied at room temperature, there are a large number of spaces between the metal powders. When this is heated to 300 ° C. and pressurized, the space is reduced and the tin powder 4 is melted to cover the surfaces of the nickel powder 3 and the copper powder 5 as shown in FIG. When further heated at 700 ° C. or higher, as shown in FIG. 5C, the molten tin 4a, nickel and copper start to be alloyed.
[0017]
Nickel is activated by this alloying, and nickel penetrates deeply into the iron base 1 to form a diffusion region over 10 μm or more. In this case, if the conventional copper plating is applied to the iron base metal, nickel is not easily diffused into the iron base metal, and a diffusion region of only about 4 μm can be obtained. Since the base metal 1 is used, a diffusion region of 10 μm or more is formed.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The superabrasive wheel of the present invention can be manufactured and used in the same procedure as a conventional superabrasive wheel except that the composition of the bond material is different.
Hereinafter, the composition of the bond material in the present invention will be described in detail based on experimental examples.
[0019]
[Experimental Example 1] Examination of composition ratio of nickel and tin When the ratio of nickel to the weight of the entire bond material was fixed to 50 wt%, the ratio of tin to nickel was changed in the range of 0 to 50 wt%. The diffusion region and adhesion strength of nickel to the base metal are shown in FIG. 2, the ratio of tin to nickel is fixed to 20% by weight, and the ratio of nickel to the total weight of the bond material is changed in the range of 0 to 70% by weight. FIG. 3 shows the diffusion region and adhesion strength of nickel to the base metal.
[0020]
As shown in FIG. 2, when the ratio of tin to nickel was 15 to 35% by weight, the result was that the diffusion region of nickel into the base metal was 10 μm or more and the adhesive strength was 100 Kgf / cm or more. As shown in FIG. 3, when the ratio of nickel to the total weight of the bond material is 15% by weight or more, the diffusion region of nickel into the base metal is 10 μm or more and the adhesive strength is 100 Kgf / cm or more. Obtained.
[0021]
[Experimental Example 2] Investigation of relationship between diffusion region and bond strength / fatigue strength The ratio of nickel to the weight of the entire bond material and the ratio of tin to nickel were varied so that the diffusion region of nickel into the base metal was in the range of 0 to 20 μm. FIG. 4 shows the results of manufacturing a superabrasive wheel and examining the adhesive strength and fatigue strength. Here, the fatigue strength is represented by the number of repetitions until the bonded portion is subjected to fatigue failure by repeatedly applying stress to the bonded portion.
[0022]
As shown in FIG. 4, when the diffusion region of nickel to the base metal is 10 μm or more, the adhesive strength is 100 kgf / cm or more, and the fatigue strength (the number of repetitions until fatigue failure) is 10,000 times or more. Adhesive strength and fatigue strength similar to those obtained when copper plating is applied to the gold surface can be obtained.
[0023]
[Experimental Example 3] Investigation of relationship between sintering temperature and diffusion region / abrasive crushability The ratio of nickel to the total weight of the bond material is 15% by weight or more and the ratio of tin to nickel is in the range of 15 to 35% by weight. FIG. 5 shows the results of investigating the relationship between the sintering temperature, the diffusion region, and the grindability of the abrasive grains when sintered using the bond material. Here, the grindability of the abrasive grains is determined by placing the heated sample abrasive grains and steel balls in a steel capsule and shaking them for a certain period of time. Then, the abrasive grains in the capsule are taken out and sieved one step below the sample abrasive grains. When sieving is carried out, it is expressed as a sieve passing amount one step below (g) / total weight of sample abrasive grains (g) × 100 (%).
[0024]
As shown in FIG. 5, when the sintering temperature is 700 ° C. or higher, the diffusion region of nickel into the base metal becomes 10 μm or more. On the other hand, when the sintering temperature exceeds 1000 ° C., the metal inclusions in the abrasive grains break the abrasive grains due to thermal stress to generate cracks, and the friability of the abrasive grains increases rapidly. From this result, it is understood that the sintering temperature is suitably in the range of 700 to 1000 ° C.
[0025]
In addition, although the said Example demonstrated what prepared nickel and tin separately and mixed this, what previously alloyed nickel powder and tin powder of the said ratio can also be used. In this case, it was confirmed that the nickel diffusion region was slightly wider when not alloyed.
[0026]
【The invention's effect】
The following effects can be achieved by the present invention.
[0027]
(1) Nickel and tin are used as metal powder, and the amount of tin with respect to nickel is in the range of 15 to 35% by weight. Bonding strength can be increased.
[0028]
(2) In particular, by setting the nickel content to 15% by weight or more of the entire bond material, the nickel diffusion region to the base metal becomes as wide as 10 μm or more, and high bonding strength can be obtained.
[0029]
(3) By using nickel and tin in a specific range, sintering can be performed at a relatively low temperature of 700 to 1000 degrees.
[0030]
(4) Manufacturing costs can be reduced by using nickel or tin, which are relatively inexpensive metal materials, and omitting copper plating of the base metal.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining the activation of nickel by melting of tin.
FIG. 2 is a diagram showing the relationship between the tin content, the diffusion region of nickel into the base metal, and the adhesive strength.
FIG. 3 is a diagram showing the relationship between the nickel content, the nickel diffusion region to the base metal, and the adhesive strength.
FIG. 4 is a diagram showing a relationship between a diffusion region and adhesive strength / fatigue strength.
FIG. 5 is a diagram showing the relationship between the sintering temperature and the diffusibility of the diffusion region and abrasive grains.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Iron base metal 2 Abrasive grain layer 3 Nickel powder 4 Tin powder 4a Molten tin 5 Copper powder

Claims (2)

A superabrasive wheel that forms a grain layer by sintering a mixture of superabrasive grains and metal powder as a bonding material, and directly joins the abrasive grain layer to the surface of an iron base metal. And at least nickel and tin are used as the metal powder, the amount of tin with respect to the nickel is in the range of 15 to 35% by weight, and the nickel content is 15% by weight or more of the entire bond material. A superabrasive wheel characterized in that the diffusion region of nickel into the base metal by ligation is 10 μm or more . A superabrasive wheel that forms a grain layer by sintering a mixture of superabrasive grains and metal powder as a bonding material, and directly joins the abrasive grain layer to the surface of an iron base metal. And at least nickel and tin are used as the metal powder, the amount of tin with respect to the nickel is in the range of 15 to 35% by weight, and the nickel content is 15% by weight or more of the entire bond material. A method for producing a superabrasive wheel in which the diffusion region of nickel into the base metal by ligation is 10 μm or more , wherein the sintering temperature is in the range of 700 to 1000 ° C. Method.

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