CN109624097B

CN109624097B - Drill bit and diamond thin-wall drill

Info

Publication number: CN109624097B
Application number: CN201811468850.9A
Authority: CN
Inventors: 邱瑜铭; 方利灵; 董先龙
Original assignee: Jiangsu Fengtai Tools Co ltd
Current assignee: Jiangsu Fengtai Tools Co ltd
Priority date: 2018-12-03
Filing date: 2018-12-03
Publication date: 2021-11-02
Anticipated expiration: 2038-12-03
Also published as: CN109624097A

Abstract

The invention relates to a drill bit and a diamond thin-wall drill, belonging to the technical field of drilling tools. The sharpening structure is arranged on the drill bit and comprises shallow grooves which are arranged on two side surfaces at intervals and extend from the working surface to the bottom surface of the drill bit; the drill bit is formed by cold pressing and sintering diamond particles and a metal binding agent to form a matrix structure, wherein the metal binding agent is composed of 15-25 wt% of electrolytic copper powder, 3-5 wt% of atomized tin powder, 3-8 wt% of carbonyl nickel powder, 5-12 wt% of FeCoCu superfine alloy powder, 10-20 wt% of FeCuNiSn superfine alloy powder, 1-10 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. The drill bit provided by the invention has a weakening structure, can keep sharpness not to be attenuated under a dry drilling condition, has good impact resistance and corrosion resistance, and can obviously reduce the phenomena of matrix cracking or tooth breakage under a high-speed dry drilling condition.

Description

Drill bit and diamond thin-wall drill

Technical Field

The invention relates to the technical field of drilling tools, in particular to a drill bit and a diamond thin-wall drill.

Background

The diamond thin-wall drill is also called engineering drill and hollow drill, and is mainly used for drilling wall holes when water, electricity, heat, gas, air conditioners and pipelines in buildings are installed. Drilling, jacking, coring and the like for basic projects such as expressways, airport runways, bridges, tunnels and the like. The diamond thin-wall drill is divided into a dry drill and a wet drill according to the field use working conditions, the dry drill is not added with cooling liquid in use, the use conditions are harsh, and the diamond thin-wall drill is generally used for drilling common cement and bricks. The wet drill is cooled by adding water through connecting a water cooling facility in the drilling process, and the drilling of reinforced concrete and hard cement generally adopts a wet drilling process. In the diamond thin-wall drill, a diamond tool bit is a key part, in order to improve cutting and heat dissipation performance, corrugated tool bits, tool bits with V-shaped or U-shaped grooves are developed in the prior art, and the tool bits improve drilling speed and the like by sharpening the whole body. But the structure such as the corrugated groove and the U-shaped groove also leads to the 'weakening' of the performance such as the integral bending strength, and the like, and the problems of cracking, even tooth breaking and the like are easy to occur under the working condition of dry drilling, particularly high-speed dry drilling. Therefore, for the design of the cutter head, the impact toughness of the cutter head is further improved on the premise of ensuring the hardness of a cutter head matrix for the cutter head with a 'weakening' structure.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide a diamond thin-wall drill bit.

The invention provides a drill bit, which is provided with a working surface and a bottom surface opposite to the working surface, wherein the bottom surface is used for being welded and fixed with a pipe body; the method is characterized in that: the drill bit is provided with a sharpening structure, the sharpening structure comprises shallow grooves which are arranged on two side surfaces of the drill bit at intervals, and the shallow grooves extend from a working surface to a bottom surface of the drill bit; the drill bit is formed by cold pressing diamond particles and a metal binding agent and sintering the diamond particles and the metal binding agent in a protective atmosphere to form a matrix structure, wherein the metal binding agent is composed of 15-25 wt% of electrolytic copper powder, 3-5 wt% of atomized tin powder, 3-8 wt% of carbonyl nickel powder, 5-12 wt% of FeCoCu superfine alloy powder, 10-20 wt% of FeCuNiSn superfine alloy powder, 1-10 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder.

Wherein the content of Co in the FeCoCu superfine alloy powder is 25 wt%, the content of Fe is 44 wt%, the content of Cu is 31 wt%, and the Fisher's particle size is 3.0-4.5 mu m.

Wherein the FeCuNiSn superfine alloy powder contains 44 wt% of Fe, 36 wt% of Cu, 12 wt% of Ni, 8 wt% of Sn and 6.0-8.0 mu m of Fisher-Tropsch particle size.

The high-chromium cast iron powder comprises 45-50 wt% of Cr, 4.5-5.0 wt% of C, 1.8-2.5 wt% of B, 0.8-1.4 wt% of Si and the balance of Fe, and the particle size of the high-chromium cast iron powder is less than 74 microns.

Wherein the impact toughness of the tire body is 3-12J/cm²。

Wherein the carcass has an erosion resistance index greater than15cm^-3。

Wherein the shallow grooves are inclined or vertically arranged in a height direction.

Wherein, the sharpening structure also comprises a groove and/or a circular arc tooth arranged on the working surface.

Wherein, the sharpening structure further comprises a groove arranged on the bottom surface.

The second aspect of the invention also relates to a diamond thin-wall drill which comprises a pipe body, a drill joint and a drill bit, wherein the drill joint is arranged at the tail end of the pipe body, and the drill bit is arranged at the front end of the pipe body through a brazing process.

Compared with the prior art, the drill bit has the following beneficial effects:

the drill bit provided by the invention has a weakening structure, can keep sharpness not to be attenuated under a dry drilling condition, has good impact resistance and corrosion resistance, and can obviously reduce the phenomena of matrix cracking or tooth breakage under a high-speed dry drilling condition.

Drawings

Fig. 1 is a schematic view of a diamond thin-wall drill bit structure according to a specific example of the present invention.

Detailed Description

The diamond thin-wall drill bit of the present invention will be further described with reference to specific embodiments to help those skilled in the art to more fully, accurately and deeply understand the inventive concept and technical solution of the present invention.

In order to ensure that the sharpness of the diamond drill bit is not reduced and the drilling speed is high, the invention provides the drill bit with a sharpening structure. Specifically, the diamond drill bit of the invention is provided with a working face and a bottom face opposite to the working face, and the bottom face is used for being welded and fixed with a pipe body to form a diamond thin-wall drill. The sharpening structure comprises shallow grooves which are arranged on two side surfaces of a drill bit at intervals, the shallow grooves extend from a working surface to a bottom surface of the drill bit, the shallow grooves are inclined or vertically arranged along the height direction, if the shallow grooves are inclined, the inclination angle with the height direction is not more than 30 degrees, otherwise, the effect of improving drilling is difficult to achieve during drilling, and the risk of carcass cracking is possibly caused. In addition, as an option, the sharpening structure may further include a groove and/or a circular arc tooth provided on the working surface, and further, the sharpening structure further includes a groove provided on the bottom surface, and the groove provided on the bottom surface may improve the discharge of chips and enhance the cooling effect, thereby improving the drilling effect.

An example of a drill bit having a sharpening structure according to the present invention is shown in fig. 1, which is a drill bit having a sharpening structure that can be applied to a dry drilling condition, according to a previous application filed by the applicant. Each cutter head 20 comprises a middle tooth section 22 and side tooth sections 21 positioned at both sides of the middle tooth section 22, and at least two continuous semicircular teeth 27 are formed on the upper parts of the middle tooth section 22 and the side tooth sections 21. A connecting section 23 is arranged between the side tooth section 21 and the middle tooth section 22; and the upper portion of the connecting section 23 is provided with a U-shaped groove 24 having both sides connected to the side tooth sections 21 and the middle tooth section 22, respectively. The cutter head is provided with a plurality of shallow grooves 26 at intervals on the inner and outer side surfaces of the side tooth sections 21, the connecting section 23 and the middle tooth section 22 in the length direction, the shallow grooves 26 extend from the top surface of the cutter head to the bottom surface of the cutter head, and the shallow grooves 26 are vertically arranged in the height direction. The lower portion of the intermediate tooth segment 21 is formed with an internal groove 25. Through setting up middle tooth section and the limit tooth section of continuous semicircle tooth, and the cooperation sets up the shallow recess that above-mentioned interval set up and makes the limit tooth section can play the cutting action at first, it is little to have area of contact, the characteristics that unit load is big, and middle tooth section plays secondary crushing effect afterwards, can be so that concrete broken crack etc. is showing and increasing when creeping into the operation, the grinding of processing object to the tool bit has been reduced, through setting up linkage segment and corresponding U-shaped groove, whole wearing and tearing have been reduced, the cooling channel has also been formed simultaneously, and chip removal ability has been improved, under the operating mode condition that need not to add cooling medium such as water, can keep dispelling the heat well, chip removal performance is outstanding, the performance that the sharpness does not attenuate. According to the requirements of diamond thin-wall drills of different specifications, the length range of the tool bit is designed to be 17-35 mm, the height H of the tool bit is designed to be 7-15 mm, and the width W of the tool bit is designed to be 2-6 mm. In the invention, the height of the inner groove 25 is 1/4-2/5 of the height H of the cutter head, preferably 1/4-1/3 of the height H of the cutter head. The depth of the U-shaped groove 24 is 1/4-2/5 of the height H of the cutter head, preferably 1/4-1/3 of the height of the cutter head. The depth of the shallow groove 26 is 1/10-1/5 of the width W of the tool bit. The drill bit can show good drilling performance under the condition of low rotating speed of the drilling machine, but if the rotating speed of the drilling machine is increased or due to manual misoperation and the like, the risk of cracking and breaking teeth exists.

For a drill bit with a "sharpening structure" (a weakening structure for the strength of the structure), such as the drill bit of the applicant's previously filed application shown in fig. 1, the impact toughness of the bit needs to be further improved on the premise of ensuring the hardness of the bit matrix, so as to prevent the safety risks of chipping, tooth breaking and the like. For this purpose, in the present invention, the metallic binder comprises 15 to 25 wt% of electrolytic copper powder, 3 to 5 wt% of atomized tin powder, 3 to 8 wt% of carbonyl nickel powder, 5 to 12 wt% of FeCoCu ultrafine alloy powder (illustratively, FeCoCu ultrafine alloy powder used in the following examples has a composition of 25 wt% of Co, 44 wt% of Fe, 31 wt% of Cu, and 3.0 to 4.5 μm in Fisher diameter), 10 to 20 wt% of FeCuNiSn ultrafine alloy powder (illustratively, FeCuNiSn ultrafine alloy powder used in the following examples has a composition of 44 wt% of Fe, 36 wt% of Cu, 12 wt% of Ni, 8 wt% of Sn, 6.0 to 8.0 μm in Fisher diameter), 1 to 10 wt% of high chromium cast iron powder (illustratively, high chromium cast iron powder used in the following examples has a composition of 45 to 50 wt% of Cr, and 4.5 to 4.5 wt% of C, b in an amount of 1.8 to 2.5 wt%, Si in an amount of 0.8 to 1.4 wt%, and Fe in the balance, and having a particle diameter of 74 μm or less), and the balance being an electrolytic iron powder. The high-chromium cast iron powder added into the metal bond has higher carbon and boron content, and part of the high-chromium cast iron powder exists in the form of carbide or boride, which is favorable for improving the strength of a sintered matrix to increase the hardness and the wear resistance of the matrix, and the carbon contained in the high-chromium cast iron powder can improve the carbon potential during sintering so as to reduce the reaction of the metal bond and the diamond and reduce the graphitization reaction of the diamond during high-temperature sintering, while the Cr is added in an alloying form to be favorable for improving the holding force of the matrix and the diamond, and compared with the Cr added in a simple substance form or the Cr added in the form of high-iron chromium iron, the negative image of the toughness is improvedThe sound is small. In addition, solid-phase sintering of cobalt can obtain a matrix with excellent performance, the matrix has excellent performance as a metal binder, and more Co is usually added to a diamond drill bit to ensure the sintering performance and the cutting capability of the diamond drill bit. However, because Co is expensive, the invention uses FeCoCu superfine alloy powder and FeCuNiSn superfine alloy powder which are substituted for cobalt, and simultaneously uses the two superfine alloy powders to obtain good sintering and cutting effects, and can still endow the tyre body with good impact toughness and erosion resistance under the condition of introducing high-chromium cast iron powder to improve the tyre body strength. The sintering can be carried out, for example, in a resistance furnace, under a protective atmosphere during the sintering, for example by passing H₂Or H₂+N₂Or by introduction of N₂Of the inert gas atmosphere. Sintering at 850-920 ℃ for 60-90 min to obtain the tire body with impact toughness of 3-12J/cm²The anti-erosion index of the matrix is more than 15cm^-3。

The oxide skin generated by the drill bit formed by sintering can prevent the cutter head from being further oxidized in the processes of storage and transportation, so that the grinding treatment is not needed firstly. And polishing when the pipe body is assembled. The good tool bit of sintering is polished the processing with L molding sand wheel to tool bit welded surface during the equipment, gets rid of the surface oxide layer, makes tool bit welded surface and the drill base member that punches reach the biggest contact surface, improves welding strength. During welding, a No. 20 steel pipe body with required specification is fixed on a clamp of a welding machine, a soldering lug and a welding flux are placed on a welding surface polished by a diamond tool bit, then the pipe body and the tool bit are fixed together, high brazing equipment is started for welding, safety bending strength detection is carried out on the tool bit according to standards, and welding is completed. Carrying out sand blasting treatment on the welded diamond thin-wall drill bit, then carrying out surface paint spraying, and testing at 600N/mm²The strength criteria were tested for bending resistance for each diamond tip.

Example 1

The adopted metal bonding agent comprises the following components: 15 weight percent of electrolytic copper powder, 3 weight percent of atomized tin powder, 8 weight percent of carbonyl nickel powder, 10 weight percent of FeCoCu superfine alloy powder, 10 weight percent of FeCuNiSn superfine alloy powder and 3 weight percent of high-chromium cast iron powderAnd the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal binder in a high-speed mixer, pressure forming in a tooling die to form a blank, sintering by using a resistance heating furnace, and sintering in a N-shaped furnace₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

Example 2

The adopted metal bonding agent comprises the following components: 25 wt% of electrolytic copper powder, 5 wt% of atomized tin powder, 3 wt% of carbonyl nickel powder, 5 wt% of FeCoCu superfine alloy powder, 20 wt% of FeCuNiSn superfine alloy powder, 5 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal binder in a high-speed mixer, pressure forming in a tooling die to form a blank, sintering by using a resistance heating furnace, and sintering in a N-shaped furnace₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

Example 3

The adopted metal bonding agent comprises the following components: 20 wt% of electrolytic copper powder, 4 wt% of atomized tin powder, 6 wt% of carbonyl nickel powder, 10 wt% of FeCoCu superfine alloy powder, 18 wt% of FeCuNiSn superfine alloy powder, 8 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal binder in a high-speed mixer, pressure forming in a tooling die to form a blank, sintering by using a resistance heating furnace, and sintering in a N-shaped furnace₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

Comparative example 1

The adopted metal bonding agent comprises the following components: 20 wt% of electrolytic copper powder, 4 wt% of atomized tin powder, 6 wt% of carbonyl nickel powder, 8 wt% of cobalt powder, 8 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal bond in a high-speed mixer, and putting the mixture into a tooling diePress forming to form a blank, sintering using a resistance furnace, and in N₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

Comparative example 2

The adopted metal bonding agent comprises the following components: 20 wt% of electrolytic copper powder, 4 wt% of atomized tin powder, 6 wt% of carbonyl nickel powder, 10 wt% of FeCoCu superfine alloy powder, 3 wt% of cobalt powder, 8 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal binder in a high-speed mixer, pressure forming in a tooling die to form a blank, sintering by using a resistance heating furnace, and sintering in a N-shaped furnace₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

Comparative example 3

The adopted metal bonding agent comprises the following components: 20 wt% of electrolytic copper powder, 4 wt% of atomized tin powder, 6 wt% of carbonyl nickel powder, 30 wt% of FeCoCu superfine alloy powder, 8 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder. Diamond was used as the hard particle, and the strength of the diamond particles was 40 kg, particle size 30/40, concentration 35%. Uniformly mixing diamond and metal binder in a high-speed mixer, pressure forming in a tooling die to form a blank, sintering by using a resistance heating furnace, and sintering in a N-shaped furnace₂Preserving the heat for 60min at 870 ℃ under the protective atmosphere.

The impact toughness and erosion resistance of the carcasses prepared in examples 1-3 and comparative examples 1-3 were measured.

The test specimen for impact toughness was 10mm × 10mm × 55mm in size, and the notch at the midpoint of the test specimen was 2mm × 2 mm. Measured on a pendulum impact tester, using a 50J pendulum. The test results were calculated as follows

a_K＝A/F

a_KIs impact toughness, J/cm²(ii) a A is the impact work, J; f is the minimum cross-sectional area of the sample under stress, cm²。

The erosion resistance of the test specimen was measured as a cylinder having a diameter of 35mm and a height of 5mm on an erosion tester, and the test specimen was eroded for a certain erosion timeThe reciprocal of the loss volume of (a) is measured as the erosion resistance Z in cm^-3。

The results of the impact toughness and erosion resistance measurements are shown in table 1.

TABLE 1

	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2	Comparative example 3
							Impact toughness (J/cm)²)	6.3	7.2	6.5	2.3	2.5	3.3
Erosion resistance (cm)^-3)	18	21	25	27	23	26

The drill bits shown in FIG. 1 were prepared using the matrix materials of examples 1 to 3 and comparative examples 1 to 3, and had a bit height of 9mm, a bit length of 21mm and a bit thickness of 2.5 mm. The depth of the U-shaped groove is 1/3 for the bit height H, the height of the inverted U-shaped groove is 1/3 for the bit height H, and the depth of the shallow groove is 1/5 for the bit width W. And welding the drill bit on a No. 20 steel pipe body with a threaded joint and a wall thickness of 0.5mm by a high-frequency induction brazing process to prepare a diamond thin-wall drill with the total length (including the total length of the pipe body, the tool bit and the threaded joint) of 180mm, and welding 4 diamond tool bits on each pipe body. The method is used for the drilling experiment of C50 concrete, and a drilling machine with the power of 3.6kW and the rotating speed of 1500r/min is adopted, and the using condition of each thin-wall drill is observed without using a cooling medium. It was found that the drill bits produced from the casings of examples 1 to 3 had substantially no tooth breakage and had fewer chipping cases, whereas the drill bits produced from the casings of comparative examples 1 to 3 had more chipping cases and had observed the tooth breakage during use.

It is obvious to those skilled in the art that the present invention is not limited to the above embodiments, and it is within the scope of the present invention to adopt various insubstantial modifications of the method concept and technical scheme of the present invention, or to directly apply the concept and technical scheme of the present invention to other occasions without modification.

Claims

1. A drill bit is provided with a working face and a bottom face opposite to the working face, wherein the bottom face is used for being welded and fixed with a pipe body; the method is characterized in that: the drill bit comprises a middle tooth section (22) and edge tooth sections (21) positioned on two sides of the middle tooth section (22), at least two continuous semicircular teeth (27) are formed on the upper portions of the middle tooth section (22) and the edge tooth sections (21), a connecting section (23) is arranged between the edge tooth sections (21) and the middle tooth section (22), and two sides of the upper portion of the connecting section (23) are respectively connected with the two sides of the upper portion of the connecting section (23)A U-shaped groove (24) reaching the side tooth section (21) and the middle tooth section (22), wherein a plurality of sharpening structures of shallow grooves (26) are arranged on the inner side surface and the outer side surface of the side tooth section (21), the connecting section (23) and the middle tooth section (22) along the length direction at intervals, and the shallow grooves (26) extend from the working surface to the bottom surface of the drill bit; the drill bit is formed by cold pressing diamond particles and a metal binder, sintering the diamond particles and the metal binder at 850-920 ℃ for 60-90 min in a protective atmosphere to form a matrix structure, wherein the impact toughness of the matrix is 3-12J/cm²The anti-erosion index of the matrix is more than 15cm^-3(ii) a The metal bonding agent comprises 15-25 wt% of electrolytic copper powder, 3-5 wt% of atomized tin powder, 3-8 wt% of carbonyl nickel powder, 5-12 wt% of FeCoCu superfine alloy powder, 10-20 wt% of FeCuNiSn superfine alloy powder, 1-10 wt% of high-chromium cast iron powder and the balance of electrolytic iron powder.

2. The drill bit of claim 1, wherein: the content of Co in the FeCoCu superfine alloy powder is 25 wt%, the content of Fe is 44 wt%, the content of Cu is 31 wt%, and the Fisher's particle size is 3.0-4.5 mu m.

3. The drill bit of claim 1, wherein: the FeCuNiSn superfine alloy powder contains 44 wt% of Fe, 36 wt% of Cu, 12 wt% of Ni, 8 wt% of Sn and 6.0-8.0 mu m of Fisher-Tropsch particle size.

4. The drill bit of claim 1, wherein: the high-chromium cast iron powder comprises 45-50 wt% of Cr, 4.5-5.0 wt% of C, 1.8-2.5 wt% of B, 0.8-1.4 wt% of Si and the balance of Fe, and the particle size of the high-chromium cast iron powder is less than 74 microns.

5. The drill bit of claim 1, wherein: the shallow grooves (26) are arranged obliquely or vertically in the height direction.

6. The drill bit of claim 1, wherein: the sharpening structure further comprises a groove and/or a circular arc tooth arranged on the working surface.

7. The drill bit of claim 1, wherein: the sharpening structure further comprises a groove arranged on the bottom surface.

8. The utility model provides a diamond thin wall bores, includes body, rig joint and drill bit, and the rig joint sets up the tail end at the body, and the drill bit sets up the front end at the body through brazing process, its characterized in that: the drill bit is selected from any one of claims 1 to 7.