Cutting disk with diamond in metal sintered matrix

Abstract

The invention relates to a cutting disc comprising a core disc (12) made of a metal material and cutting segments (14) arranged on the circumference of the core disc (12), each cutting segment (14) having a metal sintered matrix (18) in which diamond is embedded. Furthermore, alumina particles (22) are embedded in the metal sintered matrix (18) of each of the cutting segments (14). The alumina particles are shaped such that they have a surface area / volume (S / V) ratio greater than 5.

Description

Technical Field

[0001] The present invention relates to a cutting wheel, which comprises the features of the preamble of claim 1. Background Art

[0002] Such cutting wheels are known in practice and are used in the form of diamond saws, especially for cutting building materials. In terms of design, the cutting wheels each comprise a substantially circular core wheel made of metal (especially steel), on the circumference of which cutting segments are provided, the cutting segments having an arc shape along the circumference, and each cutting segment having a sintered metal matrix, which is produced, for example, based on cobalt, iron and nickel. Diamond is embedded in the sintered metal matrix, which enables the cutting wheel to have the property of being able to cut or separate materials such as concrete, natural stone, etc. When cutting highly abrasive materials (such as asphalt, concrete, sand and gravel, etc.), higher requirements are imposed on the cutting segments, because the cutting process causes a high degree of adhesive wear, which may cause the diamond to prematurely fall out of the sintered metal matrix and thus be partially unused, resulting in the cutting wheel no longer meeting the requirements. Summary of the Invention

[0003] The object of the present invention is to create a cutting wheel of the above type, which exhibits improved wear resistance.

[0004] According to the present invention, this object is achieved by a cutting wheel having the features of claim 1.

[0005] According to the present invention, a cutting wheel is proposed, which comprises a core wheel made of a metallic material and cutting segments provided at the circumference of the core wheel, the core wheel being in particular substantially circular, and each cutting segment having a sintered metal matrix, in which aluminum oxide particles are embedded.

[0006] The wear resistance effect of the aluminum oxide particles is particularly affected by their geometry. For example, for aluminum oxide particles, it is particularly advantageous if the individual aluminum oxide particles are shaped such that they have a surface area / volume (A / V) ratio per unit volume greater than 5, in particular greater than 5.14. Such an A / V ratio exists in elongated particles, while the A / V ratio of a compressed or massive body or a cuboid is less than this value. For example, a slender cuboid with side lengths of 6 mm, 0.9 mm and 0.7 mm has a surface area A of 20.46 mm 2 and a volume of 3.78 mm 3 which results in an A / V ratio of 5.41 mm -1 . In contrast, a massive cuboid with side lengths of 4 mm, 1 mm and 1.2 mm has a surface area of 4.6 mm -1A / V ratio.

[0007] Adding alumina particles to a sintered metal matrix that forms a bonding system significantly increases the abrasion resistance of the grinding section. Alumina can be obtained at a low price, which is why the cutting wheel configured according to the present invention can also be produced at low cost. In addition, the alumina particles can be fine-grained, thus producing a cutting edge that contributes to the cutting effect on building materials (such as asphalt) during cutting use.

[0008] The alumina particles are lighter in color and thus clearly visible from the sintered metal matrix, which means that the characteristics of the cutting wheel configured according to the present invention can also be intuitively perceived by the customer or user.

[0009] The cutting wheel according to the present invention is particularly suitable for cutting highly abrasive materials such as asphalt, concrete, etc.

[0010] In addition, it has been shown that if the alumina particles are all rod-shaped, the abrasion resistance of the cutting section can be improved.

[0011] In another specific embodiment of the cutting wheel according to the present invention, the aluminum particles are provided with hollow portions on their surfaces, which results in a further increase in the surface area / volume (A / V) ratio.

[0012] Depending on the application, the content of the alumina particles in the sintered metal matrix can vary. However, in particular, the content of the alumina particles in each sintered metal matrix is preferably 1 to 30% by weight, particularly 2 to 20% by weight.

[0013] It is conceivable that the alumina particles are crystalline. The alumina particles are generally each made of sintered corundum (i.e., a ceramic material).

[0014] The alumina particles can be statically distributed in the sintered metal matrix. However, in a specific embodiment of the cutting wheel according to the present invention, the alumina particles are regularly arranged and / or arranged in a pattern in the sintered metal matrix, which has a positive effect on the abrasion resistance.

[0015] The cutting section is particularly produced by sintering powders or granules.

[0016] The sintered metal matrix of the cutting section of the cutting wheel according to the present invention can include various metals such as cobalt, iron, tin, and nickel. Preferably, the sintered metal matrix has an iron, tin, nickel, and / or cobalt content in the range of 8 to 75% by weight, which is added in the form of powder or granules during the production of the cutting section.

[0017] In addition, the sintered metal matrix may preferably contain copper and / or a copper-based alloy (bronze) in an amount of 5 to 40% by weight. These components may also be added in the form of powders or granules during the production of the cutting segment, i.e., before sintering. The copper added in this way can react with the alumina particles and result in good bonding of the alumina particles, especially by forming spinel.

[0018] In addition, the sintered metal matrix may include hard materials and / or hard material alloys in an amount of 0.1 to 40% by weight. Hard material alloys include, for example, hard materials sold under the trade names Colmonoy or Deloro, which are metal or intermetallic (self-flowing) hard material alloys based on nickel, silicon, and boron.

[0019] In addition, it is advantageous if the sintered metal matrix contains iron phosphide. Its content is preferably 0.5 to 50% by weight. The phosphorus of the iron phosphide reduces the alumina on the surface of the alumina particles to metallic aluminum. The latter can be easily sintered together with metal powders or metal granules during the production of the cutting segment and increases the hardness of the sintered metal matrix.

[0020] The resulting phosphorus-iron bond ensures good wetting of all particles, especially alumina particles, during sintering, especially in the case of adding copper and / or tin and / or bronze. Under the influence of high sintering temperatures and high sintering pressures, phosphorus can react with alumina, resulting in deoxidation of the latter. This produces a thin aluminum coating on the alumina particles. The coating ensures good bonding of the aluminum particles in the sintered metal matrix.

[0021] Other advantages and advantageous configurations of the subject matter of the invention are apparent from the description, the drawings, and the claims.

[0022] An embodiment of the cutting wheel according to the invention is shown in the drawings in a schematically simplified manner and will be explained in more detail in the following description. Description of the Drawings

[0023] The only figure in the drawings shows a schematic partial view of a cutting wheel according to the invention, which forms a diamond saw. Detailed Description

[0024] The figure shows a cutting wheel 10 that is particularly suitable for cutting materials such as asphalt. The cutting wheel 10 includes a substantially circular core wheel 12 made of steel and having a central hole 13 for the drive shaft of a suitable machine tool.

[0025] On its circumference, the core wheel 12 carries a plurality of cutting segments 14 which are arranged one after another in the circumferential direction and are separated from each other by slots or incisions 16 which also extend into the core wheel 12. The cutting segments 14 constitute the cutting means of the cutting wheel 10 and are connected to the core wheel, in particular, by means of a laser welding process using a CO 2 laser or a fiber laser, or alternatively by means of a soldering process or an adhesive bonding process. In the present case, each cutting segment 14 has an arcuate shape which follows the circumference of the core wheel 12.

[0026] Each cutting segment 14 has a sintered metal matrix 18 which is made of 10 to 75 wt% iron powder, 5 to 40 wt% copper or copper-based alloy powder, 0 to 40 wt% hard material and 0.5 to 15 wt% iron phosphide powder. In addition, each cutting segment 14 includes rod-shaped alumina particles 22 in an amount of 1 to 30 wt% and diamond 20 as a cutting active substance. The alumina particles 22 and the diamond 20 are embedded in the sintered metal matrix 18.

[0027] The alumina particles 22 made of sintered corundum each have a rod-shaped geometry and a surface area / volume ratio per unit length of at least 5.14.

[0028] In the root region adjacent to the core wheel 12, the cutting segment 14 particularly has a composition different from that of the actual cutting matrix, and due to the connection welding process, this composition contains more cobalt and / or iron and / or nickel and less copper and / or bronze.

[0029] Reference numerals

[0030] 10 Cutting wheel

[0031] 12 Core wheel

[0032] 13 Hole

[0033] 14 Cutting segment

[0034] 16 Incision

[0035] 18 Sintered metal matrix

[0036] 20 Diamond

[0037] 22 Alumina particles

Claims

1. A cutting wheel, the cutting wheel comprising a core wheel (12) made of a metallic material and cutting segments (14) provided at the circumference of the core wheel (12), each cutting segment (14) having a sintered metal matrix (18), diamond (20) being embedded in the sintered metal matrix (18), and alumina particles (22) being embedded in the sintered metal matrix (18) of each of the cutting segments (14). Characterized in that the alumina particles (22) are shaped such that they each have a surface area / volume (A / V) ratio greater than 5.

2. The cutting wheel according to claim 1, Characterized in that the alumina particles (22) are all rod-shaped.

3. The cutting wheel according to claim 1 or 2, Characterized in that the content of the alumina particles (22) in the sintered metal matrix (18) is 1 to 30% by weight.

4. The cutting wheel according to any one of claims 1 to 3, Characterized in that the alumina particles (22) are made of sintered corundum.

5. The cutting wheel according to any one of claims 1 to 4, Characterized in that the sintered metal matrix (18) contains 8 to 75% by weight of iron, nickel, tin and / or cobalt.

6. The cutting wheel according to any one of claims 1 to 5, Characterized in that the sintered metal matrix (18) contains 5 to 40% by weight of copper and / or a copper-based alloy.

7. The cutting wheel according to any one of claims 1 to 6, Characterized in that the sintered metal matrix (18) contains 0.1 to 40% by weight of a hard material and / or a hard material alloy.

8. The cutting wheel according to any one of claims 1 to 7, Characterized in that the sintered metal matrix (18) contains 0.5 to 15% by weight of iron phosphide.

9. The cutting wheel according to any one of claims 1 to 8, Characterized in that the alumina particles (22) are arranged regularly and / or in a pattern in the sintered metal matrix (18).

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