CN1328027C - Method for processing crystal combination diamond and products thereof - Google Patents

Abstract

The processing method and product of the polycrystalline diamond nozzle are characterized in that: before sintering the green body, the pre-embedded part is pressed into an embedded part with a pre-embedded material that is easier to process than diamond, and the pre-embedded part is placed in the center of the three-dimensional assembly block before high-pressure synthesis position, then fill the space around the embedded parts in the assembly block with diamond powder added with binder, sinter at ultra-high pressure and high temperature to form a polycrystalline diamond nozzle body with a central hole embedded area, and then remove it by piercing Embed the part of the body, and make the aperture meet the nozzle aperture requirements. The method of the invention makes the processing of the polycrystalline diamond nozzle simple and easy, and reduces the processing cost. The polycrystalline diamond nozzle with a jacket processed by the method of the invention has the advantages of being easy to precisely process the external dimensions and having a protective effect on the nozzle.

Description

Processing method and product of polycrystalline diamond nozzle

technical field

The invention belongs to a processing method of a mechanical processing tool and a product manufactured by the method, in particular to a processing method of a polycrystalline diamond nozzle and a nozzle manufactured by the method.

Background technique

In the process of sandblasting and shot peening of metal surfaces, alumina ceramic nozzles, hard alloy nozzles or boron carbide nozzles are widely used at present. Due to the high hardness of the injection materials, the consumption of the nozzles is very large, and the nozzles need to be replaced frequently . Polycrystalline diamond (or polycrystalline diamond) is a material sintered by diamond micropowder and a small amount of binder under ultra-high pressure and high temperature. The polycrystalline diamond nozzle made of this material has high hardness, good wear resistance and long service life. It is 5-10 times that of boron carbide nozzles and 50-200 times that of cemented carbide nozzles, but the processing is very difficult. Ordinary machining methods are almost impossible, but using electric discharge machining or laser machining, it will cost a lot to process a polycrystalline diamond blank with holes, so it is difficult to widely apply polycrystalline diamond nozzles. Obstacles to overcome. The 87101729 patent discloses two schemes for processing diamond nozzles: one scheme is to mix single crystal diamond powder with metal powder and sinter them together by traditional powder metallurgy method, which is actually to wrap single crystal diamond particles with metal, once the metal is combined If the phase is worn away, the diamond particles will also fall off, and the high wear resistance of the diamond particles cannot be fully reflected, and the effect is poor; another solution is to use polycrystalline diamond to form a round hole, and the polycrystalline diamond blocks are still fixed. Depending on the metal phase, the defects of the first solution still exist, and the round hole formed is actually a quasi-round hole, and the joints of polycrystalline diamonds are discontinuous. Although this method avoids the difficult problem of polycrystalline diamond processing, such nozzle products are also very unsatisfactory.

Contents of the invention

The technical problem to be solved by the present invention is to provide an easy-to-implement processing method for polycrystalline diamond nozzles and products processed by the method.

The method to solve the above problems is: put the diamond powder added with the binder in the assembly block and sinter it into a polycrystalline diamond nozzle body with ultra-high pressure and high temperature. The feature is that before sintering the body, it is easy to process with diamond The pre-embedded material is pressed into an embedded part according to the shape and size of the inner hole of the nozzle, and the embedded part is placed in the center of the three-dimensional assembly block before high-pressure synthesis, and the diamond powder added with the binder is filled in the assembly block for pre-embedding In the space around the workpiece, the polycrystalline diamond nozzle blank with a central hole pre-buried area is sintered by ultra-high pressure and high temperature, and then the part of the embedded part is removed by a perforation process, and the hole diameter meets the nozzle hole diameter requirement.

The above-mentioned pre-embedded materials that are easy to process can be easy to machine, and/or easy to EDM, and/or easy to laser process, etc., so after ultra-high pressure and high temperature sintering, corresponding machining and/or Drilling methods such as electric discharge machining and/or laser machining process the pre-embedded area.

When the present invention selects the pre-embedded material, it is considered that the pre-embedded material will be sintered together with the diamond and the bonding agent, so the selected material should not affect the normal sintering of the diamond and the bonding agent under high temperature and high pressure, and it should be kept compatible with the nozzle material. have similar shrinkage. For example: if the pre-embedded material adopts a metal with a too low melting point, during the heating process, when the binder is not yet melted, the low melting point metal will first melt and infiltrate into the sintered material of the nozzle, which will reduce the performance of the nozzle after sintering; and if If the shrinkage rate difference between the embedded part and the nozzle is too large during sintering, it may cause the shrinkage and expansion of the embedded part to be too different from that of the nozzle core, which will cause the nozzle core to crack and deform. Therefore, when selecting the embedded material, the above effects should be considered. Factors of diamond sintering quality. Generally, the same type of raw material as the nozzle core binder can be used as the embedded material, and the proportion of individual components can be appropriately increased to improve the processability of the embedded part, and at the same time pay attention to the appropriate shrinkage rate, which is more convenient and reliable, and will not Prevents sintering of the nozzle core.

A further method of the present invention is as follows: the metal or non-metal outer surface is tightly fitted on the body of the polycrystalline diamond nozzle whose inner hole has been processed.

The above-mentioned metal jacket can be stainless steel, ordinary carbon steel or alloy steel, copper and its alloys, aluminum and its alloys, hard alloy, etc. The non-metal jacket can be made of nylon, plastic, hard rubber and other materials, and the wall thickness of the jacket is usually 1 The connection method with the polycrystalline diamond nozzle core can be connected by interference tight fit method, brazing method or powder metallurgy hot pressing mosaic method.

A further solution of the present invention is: several pieces of polycrystalline diamond nozzle chips having processed inner holes of the same diameter are superimposed and connected together in axial surface contact, and embedded in the metal jacket with surface contact and tight fit.

The above-mentioned polycrystalline diamond sheets that are superimposed and connected together in axial surface contact can be bonded and connected with an adhesive.

The method of setting the pre-embedded area adopted by the invention makes the processing of the polycrystalline diamond nozzle simple and feasible, and reduces the processing cost.

In the further scheme of the method of the present invention, the polycrystalline diamond nozzle is covered with a metal or non-metallic casing. On the one hand, only a simple machining method can be used to make the nozzle meet the requirements of precise external dimensions, and on the other hand, the polycrystalline diamond nozzle can Play a very good protective role.

The method of stacking combined nozzles adopted in the further scheme of the method of the present invention makes it possible to process extra-long polycrystalline diamond nozzles.

Description of drawings:

Fig. 1, the schematic diagram of the split state structure of the product embodiment 1 of the present invention,

Fig. 2, the schematic diagram of the split state structure of product embodiment 2 of the present invention

Fig. 3, the structure schematic diagram of product embodiment 3 of the present invention

1-Polycrystalline diamond nozzle 2-Metal jacket 3-Metal sealing ring with tapered surface

specific implementation plan

Embodiment one

1. Mix metal nickel powder with diamond powder, the nickel content is 55%wt (usually when the nickel content is greater than 40%wt, it is easy to carry out EDM), and the mixed powder is pressed into a circle with a diameter of 6 mm and a length of 30 mm Rod as pre-embedded rod;

2. Fix the pre-embedded rod on the central axis of the assembly block before high-pressure synthesis, and fill the periphery of the pre-embedded rod with diamond mixed powder containing 20% metal nickel powder. After sintering at an ultra-high pressure and high temperature at 60,000 atmospheres and 1500 ° C, the belt The polycrystalline diamond blank in the pre-embedded area, at this time, the diameter of the pre-embedded area is less than 6 mm;

3. Use a grinding machine to grind the two end faces of the polycrystalline diamond body flat, and use a centerless grinder to grind the outer circle. The diameter of the outer circle is 14mm and the length is 25mm;

4. Use a 6mm red copper electrode to punch through the area with high metal content in the center on the electric spark piercer, and process a polycrystalline diamond nozzle core with an inner diameter of 6mm;

5. As shown in Figure 1, press the polycrystalline diamond nozzle core 1 through the hole tightly into the stainless steel jacket 2, and then press the stainless steel ring 3 with an inclined cone surface into the stainless steel jacket. Use a lathe to process the stainless steel jacket to the specified size, with an outer diameter of 20 mm and a total length of 35 mm.

Usually, if the size of the pressed embedded part is the same as the inner diameter of the nozzle, the diameter of the embedded part will be slightly reduced after high temperature and high pressure sintering, so a certain processing allowance can be reserved for the perforation, and a little polycrystalline diamond hole wall is slightly removed, that is It can meet the requirements of nozzle aperture, and ensure that the hole wall is made of polycrystalline diamond with high hardness and high wear resistance.

The polycrystalline diamond nozzle in this example is compared with the carbide nozzle and boron carbide nozzle of the same specification, and the metal surface with high hardness is sandblasted with 24 mesh green silicon carbide sand. The carbide nozzle can use 8-10 working shifts; boron carbide nozzles can be used for 70-80 working shifts; in this case, polycrystalline diamond nozzles can be used for 350-500 working shifts.

Embodiment two

1. Mix metal iron powder with silicon carbide powder, the content of metal iron is 35%wt (usually, it is easy to carry out EDM when the metal iron content is greater than 30%wt), and then press the mixed powder into a diameter of 10 mm, high 6mm round rods are used as pre-embedded rods;

2. Fix the pre-embedded rod in the center of the assembly block before high-pressure synthesis, fill the periphery with diamond powder, put metal cobalt sheets on the diamond powder and pre-embedded rod, and undergo ultra-high pressure and high-temperature sintering at 60,000 atmospheres and 1450 ° C to obtain A polycrystalline diamond nozzle blank with a pre-buried area, where the diameter of the pre-buried area is less than 10 mm;

3. Use a grinding machine to grind the two ends of the above-mentioned polycrystalline diamond nozzle blanks to make them smooth, and use a centerless grinder to grind their outer circles. The outer diameter of each nozzle core is 14 mm and the height is 5 mm;

4. Use a 10 mm copper electrode to punch through the area with high metal content in the center on the electric spark piercer to obtain a polycrystalline diamond core with a 10 mm inner hole;

5. Referring to Figure 2, connect the five polycrystalline diamond nozzle 1 chips passing through the hole with AB glue. When bonding, use a graphite rod with a diameter of 10 mm to thread the five chips together to ensure the integrity of the five chips. Align the center holes of the nozzles, press the bonded combined nozzle core tightly into the brass jacket 2, then press the brass ring 3 with an inclined cone into the brass jacket, and process the jacket to the specified size with a lathe.

Embodiment three

1. Mix metal nickel powder, copper powder and diamond powder. In order to facilitate EDM, the total content of metal powder should be greater than 40%wt. In this example, it is 45%wt. Press the mixed powder into diameters of 12mm, A round rod with a length of 30 mm and a cone with a diameter of 20 mm at one end, a diameter of 7.2 mm at the other end and a height of 12 mm are used as embedded parts;

2. Put the embedded part in the center of the assembly block before high-pressure synthesis, and the periphery is surrounded by diamond mixed powder containing 12%wt silicon and 3%wt titanium. After 60,000 atmospheres of pressure and higher than 1500℃, the ultra-high pressure and high temperature sintering , to obtain a polycrystalline diamond nozzle body with a pre-embedded area;

3. Grind both ends of the obtained polycrystalline diamond nozzle blank with a grinder, and grind its outer circle with a centerless grinder. The outer diameter of the nozzle core is 20 mm and the length is 35 mm;

4. Use a 6 mm red copper electrode to punch through the area with high metal content in the center on the electric spark piercer to obtain a polycrystalline diamond with a 6 mm inner hole; then use an electrode with a specified angle to rotate the perforated polycrystalline diamond body Cut out the conical surface to get the whole polycrystalline diamond nozzle.

Embodiment Four

1. Mix metal nickel powder with silicon carbide micropowder, the nickel content is 55%wt (usually when the nickel content is greater than 40%wt, it is easy to carry out laser processing), and press the mixed powder into a circle with a diameter of 10mm and a height of 6mm The film is used as a pre-embedded film;

2. Fix the embedded chip on the central axis of the assembly block before high-pressure synthesis, fill the periphery of the embedded chip with diamond mixed powder containing 15% metal nickel powder, and undergo ultra-high pressure and high temperature sintering at 60,000 atmospheres and 1500 ° C to obtain a strip The polycrystalline diamond blank in the pre-embedded area, the diameter of the pre-embedded area is slightly less than 10 mm at this time;

3. Use a grinding machine to grind the two ends of the 10 pieces of polycrystalline diamond nozzle blanks to make them smooth, and use a centerless grinder to grind their outer circles. The outer diameter of each nozzle core is 25 mm and the height is 5 mm;

4. Put it on a laser cutting machine to cut off the area with high metal content in the center, and process it to obtain a polycrystalline diamond nozzle core with an inner diameter of 10mm;

5. Press the polycrystalline diamond core through the hole tightly into the stainless steel jacket, and then press the stainless steel ring with an inclined cone into the stainless steel jacket. Use a lathe to process the stainless steel jacket to the specified size, with an outer diameter of 35 mm and a total length of 60 mm.

This scheme is mainly suitable for the production of large-aperture nozzles.

The above-mentioned embedded materials that are easier to process than diamond can be summarized as follows: adding not less than 30% wt of iron group metals or their alloy materials to diamond and silicon carbide.

Embodiment five

1. Obtain a sheet-shaped nozzle core in the same manner as steps "1" and "2" in Example 4. Use a grinder to grind the two ends of the above-mentioned polycrystalline diamond nozzle blanks to make them smooth, and grind their outer circles with a centerless grinder. The outer diameter of each nozzle core is 14 mm and the height is 5 mm;

2. On the ultrasonic machine, select the tubular cutting head supplemented by diamond abrasives to mechanically cut off the area with high metal content in the center, and process the polycrystalline diamond nozzle core with an inner diameter of 6mm;

3. Press the polycrystalline diamond nozzle core through the hole tightly into the nylon jacket, and then press the nylon ring with inclined tapered surface into the nylon jacket. Use a lathe to process the nylon jacket to the specified size, with an outer diameter of 20 mm and a total length of 35 mm.

According to the comprehensive requirements of processing efficiency and processing accuracy, two or three methods of machining, EDM, and laser processing can also be selected for combined processing.

The polycrystalline diamond of the present invention can be the growth sintered polycrystalline diamond (such as embodiment two) that adds catalyst metal to make binding agent to make, also can be the sintered polycrystalline diamond that adds strong carbide element to make binding agent to make ( As embodiment three). The method of adding the binder can be a powder mixing method, an impregnation method, or a diamond powder surface coating method.

The method of the invention is also applicable to the processing of polycrystalline diamond products other than nozzles.

Claims (6)

1, the processing method of crystal combination diamond, place assembled block to sinter the crystal combination diamond base substrate into the bortz powder that has added bond with high pressure high temperature, it is characterized in that: before sintered body, use the pre-buried material that is easy to process than diamond to be pressed into built-in fitting earlier by nozzle endoporus geomery, place height to be pressed into preceding three-dimensional assembled block center built-in fitting, the described bortz powder that has added bond is filled in the space around the built-in fitting in the assembled block, sinter the crystal combination diamond base substrate in the pre-buried district of band centre bore into through high pressure high temperature, remove the built-in fitting body portion with method of perforation processing then, and make the aperture reach the nozzle bore requirement.

2, the processing method of crystal combination diamond according to claim 1 is characterized in that: metal or the contact of nonmetal circumferential surface are enclosed within outside the crystal combination diamond core that processes endoporus tightly.

3, the processing method of crystal combination diamond according to claim 2, it is characterized in that: the some crystal combination diamond chip axial vane surface contact stacks that process the same apertures endoporus are linked together, and the face contact embeds in the described overcoat tightly.

4, according to the processing method of claim 1,2 or 3 described crystal combination diamonds, it is characterized in that: the described pre-buried material that is easy to process is to add iron group metal or its alloy material that is no less than 30%wt in diamond, carborundum.

5, crystal combination diamond is characterized in that: outside crystal combination diamond, face tight fit contiguously is with metal or nonmetal overcoat.

6, crystal combination diamond according to claim 5 is characterized in that: described crystal combination diamond is linked together by the polycrystalline diamond sheet axial vane surface contact stack in some band identical central holes and forms.