Long-service-life brazed diamond grinding block and preparation process

Abstract

The invention discloses a long-life brazed diamond grinding block and a preparation process thereof. The long-service-life brazed diamond grinding block is composed of a plurality of multi-layer units and filler between the units. The multi-layer units are prepared from sintered pure iron compacts, diamond particles distributed on the surfaces of the sintered pure iron compacts and alloy solder through vacuum brazing. The sintered pure iron composite sheet is prepared from iron powder and skeleton phase particles through hot pressing sintering, and the highest hot pressing sintering temperature is 1100-1250 DEG C; the skeleton phase particles are abrasive materials with the heat-resistant temperature of 1250 DEG C or above. According to the long-service-life brazed diamond grinding block obtained through the special structural design and process, diamond on the surface of a brazed diamond tool can be used in a multi-layer mode, it is guaranteed that the working efficiency is basically stable while the long service life is achieved, and the defects that a traditional multi-layer tool base body cannot be effectively abraded, and the service life is long are overcome. And the surface of the multi-layer diamond is easily blocked.

Description

Technical Field

[0001] The invention belongs to the field of brazed diamond tool manufacturing, and in particular relates to a long-life brazed diamond grinding block and a preparation process thereof. Background Art

[0002] At present, brazed diamond tools have been widely used in the field of stone materials, especially in the cutting of marble, concrete and other materials, and in the drilling of ceramic materials. Due to the advantages of high sharpness, large chip space on the tool surface and good heat dissipation, the application of brazed diamond tools can better replace electroplated diamond tools and some sintered diamond tools. However, since brazed diamond is a single-layer tool, the tool can no longer be processed after the surface diamond is worn or fails. Sintered diamond tools have the advantage of multi-layer diamond processing. For granite, ceramics or some concrete materials, sintered diamond tools are still the mainstream.

[0003] There are two main methods for increasing the life of diamond tools by multi-layer brazing of diamonds. One is to make layers on the surface of the substrate (such as CN201712070U thin brazed multi-layer diamond saw blade; CN201151217Y brazed and sintered multi-layer diamond tool with optimized abrasive arrangement) so that the distribution of diamonds on the surface of the substrate has a height difference, so as to achieve the purpose of using diamonds in multiple layers. The other is to refer to the principle of sintered diamond process (such as CN101862834B one-time forming multi-layer brazed diamond drill bit), mix brazing solder and other additives with diamonds, and realize the multi-layer diamond by a specific process. According to the current usage, these two solutions have not yet completely solved the problem of preparing multi-layer brazed diamond tools. When the layers of the substrate surface structure are changed to achieve the multi-layer wear effect of diamond particles, it is often difficult for the lower layer of diamonds to be exposed, and the substrate cannot be effectively worn, which affects the realization of the multi-layer effect, or the lower layer of diamonds is affected by the wear of the upper layer of diamonds, and the grinding chips cannot be effectively discharged, affecting the grinding efficiency. When multi-layer brazing similar to sintering process is adopted, since the brazing diamond welding strength is higher than the sintering process, the diamond is difficult to fall off, and the subsequent diamond is difficult to expose. In order to achieve exposure, it is often necessary to process pore-forming agents in the solder alloy, but the pores formed are easily blocked by grinding chips, causing the tool to lose the multi-layer effect. Summary of the invention

[0004] In view of the problem that the traditional multi-layer tool substrate cannot be worn, the present invention provides a long-life brazed diamond grinding block, which realizes the multi-layer stable grinding of diamond through structural design. The purpose of the present invention is to realize that the diamond on the surface of the brazed diamond tool can be used in multiple layers to achieve the purpose of long working life. In addition, the structure and process designed by the present invention can also ensure that the working efficiency is basically stable while achieving long life, overcoming the problem that the traditional multi-layer tool substrate cannot be effectively worn and the multi-layer diamond surface is easily blocked.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A long-life brazed diamond grinding block, which is composed of a plurality of multi-layer units and fillers between the units, wherein the multi-layer units are prepared by vacuum brazing of a sintered pure iron composite sheet and diamond particles arranged on its surface and alloy solder;

[0007] The sintered pure iron composite sheet is composed of iron powder and a skeleton phase, wherein the volume percentages are 82-99% iron powder and 1-18% skeleton phase, and the sum of the volume percentages is 100%; and the sintered pure iron composite sheet is prepared by hot pressing and sintering the iron powder and skeleton phase particles, and the maximum hot pressing and sintering temperature is 1100° C. to 1250° C.;

[0008] The purity of the iron powder reaches more than 98.5%;

[0009] The skeleton phase particles are abrasives with a heat-resistant temperature of more than 1250°C;

[0010] The filler is a ceramic binder or a metal binder.

[0011] Furthermore, the arrangement density of the diamond particles on the surface of the sintered pure iron composite sheet of the present invention is 90 to 6500 particles / cm 2 .

[0012] Furthermore, the diamond particles of the present invention are artificial diamond particles, and the particle size thereof is 20 mesh to 140 mesh.

[0013] In the present invention, by limiting parameters such as the diamond particle arrangement density and the diamond particle size, the number and concentration of diamonds in the diamond composite sheet of the main working unit are determined, thereby determining the processing efficiency and processing surface quality of the diamond tool during processing.

[0014] Furthermore, the ratio of the thickness of the filler to the thickness of the multilayer unit of the present invention is 1:1 to 5:1, and the ratio of the thickness of the filler to the multilayer unit determines the number of diamond composite sheets.

[0015] Furthermore, the multi-layer unit of the present invention is a sheet-like structure, which is perpendicular or inclined to the working surface to form an angle of 0 to 35 degrees, and the inclination angle of the multi-layer unit determines the grinding load.

[0016] Furthermore, the purity of the iron powder of the present invention is preferably above 99%, and the particle size is 600-3000 mesh.

[0017] Furthermore, the particle size of the skeleton phase particles of the present invention is 170 mesh to 2000 mesh, and is selected from any one of aluminum oxide, boron nitride, and silicon carbide or a mixture thereof. The parameters of the iron powder and the skeleton phase determine the preparation performance of the composite and affect the multi-layer application effect.

[0018] Furthermore, the alloy solder described in the present invention is a nickel-based alloy solder, whose composition is nickel-chromium-boron-silicon-iron, and the proportions of its elements are: Cr (6.0-8.0) B (2.75-3.5) Si (4.0-5.0) Fe (2.5-3.5), and the rest is nickel; the alloy solder particle size is limited to 40 mesh to 200 mesh.

[0019] Furthermore, the density of the sintered pure iron composite sheet of the present invention is 5.2 g / cm 3 -6.3g / cm, thickness is 0.6mm~1.3mm.

[0020] Furthermore, the present invention also provides a preparation process of the above-mentioned long-life brazed diamond grinding block, comprising:

[0021] (1) Preparation of multilayer units: First, a layer of binder is coated on the surface of the sintered pure iron composite sheet, and then diamond particles are arranged on the surface of the binder. Then, alloy solder is arranged in the gaps between the diamond particles. The obtained unit body is placed in a vacuum brazing furnace and heated to obtain a multilayer unit.

[0022] The vacuum brazing temperature in step (1) is 1010°C to 1026°C, the heating time from 940°C to the highest temperature is 25 to 40 minutes, the holding time is 7 to 20 minutes, and the vacuum degree during the heating process is maintained within 0.1 Pa;

[0023] (2) Preparation of long-life brazed diamond grinding blocks: The multilayer units obtained in step (1) and fillers are formed by hot pressing and sintering;

[0024] The hot pressing sintering in step (2) is a vacuum hot pressing sintering process, the maximum sintering temperature is 860° C., the holding time does not exceed 3 minutes, and the holding pressure is 22 to 28 MPa.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) Since the sintered iron sheet composite is made of pure iron powder and a skeleton phase, its hardness is relatively low. It has a certain flexibility and can maintain a certain strength, but its wear resistance is lower than that of steel. This is a beneficial feature for processing stone. When diamonds are brazed on its surface and the surface diamonds are worn, the stone will rub and wear the solder alloy layer and the composite. Since it is not wear-resistant, it can be worn away more easily, so that the diamonds on the lower layer can be exposed and continue to work. The skeleton phase in the composite is a wear-resistant phase such as aluminum oxide and silicon carbide, which can keep its shape after sintering. When worn, it is easy to fall off under the impact of the stone and easily take away heat. The gaps formed can also improve the heat dissipation effect, avoiding the situation that the steel matrix used in the conventional multi-layer structure is not easy to wear and easy to adhere to the stone surface.

[0027] (2) The processing object stone and chips, due to their high hardness, will rub and impact the sintered iron sheet composite of the multi-layer unit and the nickel-based alloy layer on the surface of the composite. Since the composite and the nickel-based alloy layer have relatively low hardness, they will be worn away by the chips, and the filler between the multi-layer units has very low strength and is easily worn away, so that the next layer of diamond can be exposed to continue working;

[0028] On the other hand, since the multi-layer units are perpendicular or maintain a certain angle with the processing surface, after the multiple multi-layer units are compounded into a whole, the diamond distribution on the surface is uniform. After the grinding process, the grinding efficiency is stable and the service life is long due to continuous wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a multi-layer unit structure in the long-life brazed diamond grinding block of the present invention.

[0030] Figure 2 This is the long-life brazed diamond grinding block structure of the present invention.

[0031] The markings in the figure are: 1 sintered pure iron composite sheet, 2 alloy solder, 3 diamond particles, and 4 filler. DETAILED DESCRIPTION

[0032] The above contents of the present invention are further described in detail below through the specific implementation of the embodiments, but are not limited to the following embodiments. The present invention includes various substitutions or changes made according to the common technical knowledge and conventional means in the above technical ideas, which should be included in the scope of the present invention.

[0033] A long-life brazed diamond grinding block, which is composed of a plurality of multi-layer units and fillers between the units, wherein the multi-layer units are prepared by vacuum brazing of a sintered pure iron composite sheet and diamond particles arranged on its surface and alloy solder;

[0034] The sintered pure iron composite sheet is composed of iron powder and a skeleton phase, wherein the volume percentages are 82-99% iron powder and 1-18% skeleton phase, and the sum of the volume percentages is 100%; and the sintered pure iron composite sheet is prepared by hot pressing and sintering the iron powder and skeleton phase particles, and the maximum hot pressing and sintering temperature is 1100° C. to 1250° C.;

[0035] The purity of the iron powder reaches more than 98.5%;

[0036] The skeleton phase particles are abrasives with a heat-resistant temperature of more than 1250°C;

[0037] The filler is a ceramic binder or a metal binder.

[0038] The arrangement density of the diamond particles on the surface of the sintered pure iron composite sheet is 90 to 6500 particles / cm 2 .

[0039] The ratio of the thickness of the filler to the thickness of the multilayer unit is 1:1 to 5:1.

[0040] The multi-layer unit is a sheet-like structure, which is perpendicular or inclined to the working surface to form an angle of 0 to 35 degrees.

[0041] The purity of the iron powder is preferably above 99%, and the particle size is 600-3000 mesh.

[0042] The particle size of the skeleton phase particles is 170-2000 meshes, and is selected from any one of aluminum oxide, boron nitride, and silicon carbide or a mixture of the above.

[0043] The diamond particles are artificial diamond particles, and the particle size thereof is 20 meshes to 140 meshes.

[0044] The alloy solder is a nickel-based alloy solder, and its composition is nickel-chromium-boron-silicon-iron, and the proportions of its elements are: Cr (6.0-8.0) B (2.75-3.5) Si (4.0-5.0) Fe (2.5-3.5), and the rest is nickel; the particle size of the alloy solder is limited to 40 mesh to 200 mesh.

[0045] The density of the sintered pure iron composite sheet is 5.2 g / cm 3 -6.3g / cm 3 , thickness is 0.6mm~1.3mm.

[0046] The preparation process of the long-life brazed diamond grinding block of the present invention comprises:

[0047] (1) Preparation of multilayer units: First, a layer of binder is coated on the surface of the sintered pure iron composite sheet, and then diamond particles are arranged on the surface of the binder. Then, alloy solder is arranged in the gaps between the diamond particles. The obtained unit body is placed in a vacuum brazing furnace and heated to obtain a multilayer unit.

[0048] The vacuum brazing temperature in step (1) is 1010°C to 1026°C, the heating time from 940°C to the highest temperature is 25 to 40 minutes, the holding time is 7 to 20 minutes, and the vacuum degree during the heating process is maintained within 0.1 Pa;

[0049] (2) Preparation of long-life brazed diamond grinding blocks: The multilayer units obtained in step (1) and fillers are formed by hot pressing and sintering;

[0050] The hot pressing sintering in step (2) is a vacuum hot pressing sintering process, the maximum sintering temperature is 860° C., the holding time does not exceed 3 minutes, and the holding pressure is 22 to 28 MPa.

[0051] Example 1

[0052] A long-life brazed diamond grinding block, which is composed of a plurality of multi-layer units and fillers between the units, wherein the multi-layer units are prepared by vacuum brazing of a sintered pure iron composite sheet and diamond particles arranged on its surface and alloy solder;

[0053] The sintered pure iron composite sheet is composed of iron powder and a skeleton phase, wherein the volume percentages are 82% iron powder and 18% skeleton phase, and the sintered pure iron composite sheet is prepared by hot pressing and sintering the iron powder and skeleton phase particles, and the maximum hot pressing and sintering temperature is 1100° C.;

[0054] The purity of the iron powder reaches more than 98.5%;

[0055] The skeleton phase particles are aluminum oxide with a heat-resistant temperature of more than 1250°C, and the particle size is 170 mesh to 2000 mesh;

[0056] The filler is a ceramic binder;

[0057] The arrangement density of the diamond particles on the surface of the sintered pure iron composite sheet is 500 particles / cm 2 ;

[0058] The ratio of the thickness of the filler to the thickness of the multilayer unit is 1:1;

[0059] The multi-layer unit is a sheet-like structure, perpendicular to the working surface;

[0060] The purity of the iron powder is preferably above 99%, and the particle size is 600-3000 mesh;

[0061] The diamond particles are artificial diamond particles, and the particle size thereof is 20 meshes to 140 meshes.

[0062] The alloy solder is a nickel-based alloy solder, and its composition is nickel-chromium-boron-silicon-iron, and the proportions of its elements are: Cr (6.0-8.0) B (2.75-3.5) Si (4.0-5.0) Fe (2.5-3.5), and the rest is nickel; the alloy solder particle size is limited to 40 mesh to 200 mesh;

[0063] The density of the sintered pure iron composite sheet is 5.2 g / cm 3 , thickness is 0.6mm.

[0064] Example 2

[0065] A long-life brazed diamond grinding block, which is composed of a plurality of multi-layer units and fillers between the units, wherein the multi-layer units are prepared by vacuum brazing of a sintered pure iron composite sheet and diamond particles arranged on its surface and alloy solder;

[0066] The sintered pure iron composite sheet is composed of iron powder and a skeleton phase, wherein the volume percentages are 99% iron powder and 1% skeleton phase, and the sum of the volume percentages is 100%; and the sintered pure iron composite sheet is prepared by hot pressing and sintering the iron powder and skeleton phase particles, and the maximum hot pressing and sintering temperature is 1250°C;

[0067] The purity of the iron powder reaches more than 98.5%;

[0068] The skeleton phase particles are boron nitride with a heat-resistant temperature of more than 1250°C, and the particle size is 170 mesh to 2000 mesh;

[0069] The filler is a metal binder;

[0070] The arrangement density of the diamond particles on the surface of the sintered pure iron composite sheet is 5500 particles / cm 2 ;

[0071] The ratio of the filler thickness to the multilayer unit thickness is 5:1.

[0072] The multi-layer unit is a sheet-like structure, which is inclined to form an angle of 35 degrees with the working surface;

[0073] The purity of the iron powder is preferably above 99%, and the particle size is 600-3000 mesh;

[0074] The diamond particles are artificial diamond particles, and the particle size thereof is 20 mesh to 140 mesh;

[0075] The alloy solder is a nickel-based alloy solder, and its composition is nickel-chromium-boron-silicon-iron, and the proportions of its elements are: Cr (6.0-8.0) B (2.75-3.5) Si (4.0-5.0) Fe (2.5-3.5), and the rest is nickel; the alloy solder particle size is limited to 40 mesh to 200 mesh;

[0076] The sintered pure iron composite sheet has a density of 6.3 g / cm and a thickness of 1.3 mm.

[0077] The long-life brazed diamond grinding block prepared by the present invention realizes multi-layer stable grinding of diamond through structural design, and at the same time ensures basic stability of working efficiency while achieving long life, and its surface is not easy to be blocked during use.

Claims

1. A long-life brazed diamond grinding block, characterized in that: The long-life brazed diamond grinding block is composed of a plurality of multi-layer units and fillers between the units, wherein the multi-layer units are prepared by vacuum brazing of a sintered pure iron composite sheet and diamond particles arranged on its surface and alloy solder; The arrangement density of the diamond particles on the surface of the sintered pure iron composite sheet is 90 to 6500 particles / cm 2 ; The sintered pure iron composite sheet is composed of iron powder and a skeleton phase, wherein the volume percentages are 82-99% iron powder and 1-18% skeleton phase, and the sum of the volume percentages is 100%; and the sintered pure iron composite sheet is prepared by hot pressing and sintering the iron powder and skeleton phase particles, and the maximum hot pressing and sintering temperature is 1100° C. to 1250° C.; The purity of the iron powder reaches more than 98.5%; The skeleton phase particles are abrasives with a heat-resistant temperature of more than 1250°C; The filler is a ceramic binder or a metal binder.

2. A long-life brazed diamond grinding block according to claim 1, characterized in that: The diamond particles are artificial diamond particles, and the particle size thereof is 20 meshes to 140 meshes.

3. A long-life brazed diamond grinding block according to claim 1, characterized in that: The ratio of the thickness of the filler to the thickness of the multilayer unit is 1:1 to 5:

1.

4. A long-life brazed diamond grinding block according to claim 1, characterized in that: The multi-layer unit is a sheet-like structure, which is perpendicular or inclined to the working surface to form an angle of 0 to 35 degrees.

5. The long-life brazed diamond grinding block according to claim 1, characterized in that: The purity of the iron powder reaches more than 99%, and its particle size is 600 mesh to 3000 mesh; The particle size of the skeleton phase particles is 170-2000 meshes, and is selected from any one of aluminum oxide, boron nitride, and silicon carbide or a mixture of the above.

6. A long-life brazed diamond grinding block according to claim 1, characterized in that: The alloy solder is a nickel-based alloy solder, and its composition is nickel-chromium-boron-silicon-iron, and the proportions of its elements are: Cr (6.0-8.0) B (2.75-3.5) Si (4.0-5.0) Fe (2.5-3.5), and the rest is nickel; the particle size of the alloy solder is limited to 40 mesh to 200 mesh.

7. A long-life brazed diamond grinding block according to claim 1, characterized in that: The density of the sintered pure iron composite sheet is 5.2 g / cm 3 -6.3g / cm, thickness is 0.6mm~1.3mm.

8. A process for preparing the long-life brazed diamond grinding block according to any one of claims 1 to 7, characterized in that: include: (1) Preparation of multilayer units: First, a layer of binder is coated on the surface of the sintered pure iron composite sheet, and then diamond particles are arranged on the surface of the binder. Then, alloy solder is arranged in the gaps between the diamond particles. The obtained unit body is placed in a vacuum brazing furnace and heated to obtain a multilayer unit. (2) Preparation of long-life brazed diamond grinding blocks: The multilayer units obtained in step (1) and the filler are formed by hot pressing and sintering.

9. The preparation process according to claim 8, characterized in that: The vacuum brazing temperature in step (1) is 1010°C to 1026°C, the heating time from 940°C to the highest temperature is 25 to 40 minutes, the holding time is 7 to 20 minutes, and the vacuum degree during the heating process is maintained within 0.1 Pa; The hot pressing sintering in step (2) is a vacuum hot pressing sintering process, the maximum sintering temperature is 860° C., the holding time does not exceed 3 minutes, and the holding pressure is 22 to 28 MPa.

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