Machining method for small sealing cavity of corrosion-resistant magnetically soft alloy product

Abstract

The invention provides a machining tool and method for a small sealing cavity of a corrosion-resistant magnetically soft alloy product. The machining tool is manufactured; selecting a cutter according to the threaded hole of the to-be-machined product, and roughly machining the threaded hole of the drilled and bored product; roughly machining a groove; threaded holes are machined in a layered mode, finish machining of the threaded holes is completed, and first buckle burrs are removed; a sealing surface is machined, and allowance is reserved on the sealing surface; a sealing tooth cutter is used for machining a sealing cavity, namely a sealing tooth, the rotating speed ranges from 2000 r / min to 2200 r / min, the rough machining feeding amount ranges from 0.02 mm / r to 0.03 mm / r, and the finish machining allowance ranges from 0.06 mm to 0.08 mm; the tool is rapidly retracted by 0.3-0.5 mm in the midway, the finish machining feed rate is 0.01-0.02 mm / r, and the tool is fed to the theoretical depth of the sealing cavity; and feeding the hole boring cutter to the minimum diameter phi 0.5-phi 1 along the inner ring of the sealing tooth, feeding the inner groove cutter to the groove diameter phi 5.3-phi 6.3 along the outer ring of the sealing tooth, removing the final allowance and burrs of the sealing tooth, and finely machining the sizes of the threaded hole and the groove by using the hole boring cutter and the inner groove cutter.

Description

Technical Field

[0001] The present invention relates to a processing tooling and a processing method for a small sealed cavity of a corrosion-resistant soft magnetic alloy product, belonging to the technical fields of product machining and machine tool fixtures. Background Art

[0002] The product at the bottom of a certain housing is made of corrosion-resistant soft magnetic alloy Cr17NiTi material, and its shape is mainly composed of a rotary body stepped circle and a small threaded inner cavity on the side. The following problems mainly exist in the production process:

[0003] 1. The alignment and processing time are too long: Due to the irregular shape of the product, a combined fixture is generally selected for the clamping method when machining the side threaded holes. However, the traditional combined fixture has great disadvantages, and the clamping, alignment, and processing time of a single product are relatively long, with an average of 25 minutes per single piece, which can no longer meet the requirements of fast-paced mass production. There is an urgent need for a new tooling to replace the traditional tooling.

[0004] 2. It is easy to break the tool when machining the small sealed cavity: The threaded base hole of the sealed cavity of this product is Φ4.5 - Φ5.5, and the bottom end face is a flat bottom hole, which limits the tool diameter. Machining the product with a small tool has high requirements for tool grinding and the selection of the machining route. At the same time, the material of this product has good plasticity, toughness, and large viscosity, and it is easy to entangle chips when machining the inner cavity of the small blind hole, resulting in tool breakage. Re-clamping the tool pair; when finely machining the small sealed teeth (60° end face annular groove) with Φ2.1 - Φ4.1 as attached Figure 4 When machining the ΦE dimension, the surface roughness is too large, and defects such as chatter marks, fish scale marks, and tool sticking are likely to appear on the sealed teeth.

[0005] 3. Manually brushing the coolant is time-consuming: The product is made of corrosion-resistant soft magnetic alloy Cr17NiTi material with an irregular shape. Using a combined fixture for clamping in the traditional method, the rotation speed cannot be set too high. When machining the small sealed cavity, the surface roughness cannot reach the requirement with the machine tool coolant. In a low rotation speed environment, only the traditional cooling method of carbon tetrachloride plus lard can be used, and the coolant needs to be manually brushed to meet the roughness requirement of the product. The processing efficiency is slow. Therefore, while improving the roughness, the processing time also needs to be shortened.

[0006] Currently, there is no similar high-quality solution at home and abroad. Summary of the Invention

[0007] The technical problem solved by the present invention is: to make a new tooling to replace the traditional combined fixture, reduce the clamping, alignment, and processing time of a single product. The size of the tooling is adapted to the product, a high rotation speed can be set during processing, and the machine tool self-spraying coolant is used to replace manual brushing of the coolant to ensure the roughness of the bottom end face of the sealed cavity.

[0008] The technical solution of the present invention is as follows: A processing method for a small sealing cavity of a corrosion-resistant soft magnetic alloy product. The side of the soft magnetic alloy product has a threaded hole to be processed. The bottom of the threaded hole is a groove, and the bottom of the groove is a sealing surface. A sealing cavity is provided on the sealing surface, including:

[0009] Manufacture a processing tooling; the tooling includes a tooling body and a cover plate. One end of the tooling body is a clamping part, and the other end is provided with an installation plane. A keyway is provided on the installation plane. The keyway matches the lower end face of the product to be processed. The product is sleeved on the installation plane by the sleeving principle and the surface to be processed is exposed on the side of the installation plane. The upper end of the product is fixedly connected to the tooling body through a cover plate fastener;

[0010] Select a tool according to the threaded hole of the product to be processed, and drill and bore the product for rough machining of the threaded hole;

[0011] Rough machine the groove;

[0012] Machine the threaded hole in layers, complete the finish machining of the threaded hole and remove the burrs of the first thread;

[0013] Machine the sealing surface, leaving a margin on the sealing surface;

[0014] Use a sealing tooth cutter to machine the sealing cavity, that is, the sealing teeth (the depth is generally 0.3mm ± 0.05), the rotational speed is 2000 to 2200r / min, the rough machining feed rate is 0.02 to 0.03mm / r, leaving a finish machining margin of 0.06 to 0.08mm; first machine the depth to 0.15 ± 0.05, retract the tool by 0.3 to 0.5mm with the G0 code halfway, and then machine the depth to 0.22 to 0.24mm; the finish machining feed rate is 0.01 to 0.02mm / r, and feed to the theoretical depth of the sealing cavity;

[0015] Use a boring cutter to feed along the inner circle of the sealing teeth towards the minimum diameter, and use an inner groove cutter to feed along the outer circle of the sealing teeth towards the groove diameter to remove the remaining margin on the bottom end face of the final hole and the burrs of the sealing teeth;

[0016] Use a boring cutter and an inner groove cutter to finish machine the dimensions of the threaded hole and the groove.

[0017] Preferably, use a machining center equipment to machine the product tooling. Ensure that after the product is installed at the machining part of the tooling, the total runout of the central axis of the product relative to the central axis of the tooling is within 0.01mm. At the same time, ensure the accuracy of the keyway width value is G ± 0.01mm, where G is the width of the end face convex part of the product threaded hole.

[0018] Preferably, detect and align the position of the axis of the product tooling with respect to the first-piece product, and subsequent batch machining of products does not require repeated alignment.

[0019] Preferably, during the rough machining of the groove, a stepped feed method is adopted, with a pause between two feeds, and chips are blown away by gas. The depth of cut ≤ 0.3 mm.

[0020] Preferably, the machining of the threaded hole includes:

[0021] In the first layer of rough machining, 0.3 - 0.4 mm of stock is removed, and the depth of cut for each pass decreases from 0.2 - 0.15 mm to 0.1 - 0.05 mm;

[0022] In the second layer of finish machining, the remaining stock is removed, and the depth of cut for each pass is 0.05 - 0.03 mm;

[0023] After the threaded hole is finish - machined, a boring tool should be used to remove the burrs on the first thread.

[0024] Preferably, when machining the bottom end face of the sealing surface with a boring tool, 0.03 - 0.01 mm of stock is left.

[0025] Preferably, for the selected internal groove tool, boring tool, and sealing tooth tool, the rake angle of the tool is in the range of 10° to 15°, the hardness value is HRC55 - 65, and a rounded chip - evacuation groove is ground.

[0026] Preferably, the said sealing tooth is a 60° end - face annular groove, the center diameter of the sealing tooth is Φ2.1 - 4.1 mm, and the product material is Cr17NiTi. To prevent vibration marks on the sealing tooth, a rotational speed of 2000 to 2200 r / min is selected, and the G04 program code pause is not allowed during finish machining.

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] 1. Due to the use of a self - made tooling, the rotational speed can be increased to 2000 - 3000 r / min. At the same time, when machining the bottom end face of the inner - cavity seal, a stepped machining method is selected, and the machine - tool's built - in cooling system is used, which solves the problem of excessive roughness of the bottom end face and avoids the time - consuming problem of manually brushing the coolant.

[0029] 2. At the same time, after multiple tests, when machining small - diameter sealing teeth of Cr17NiTi material, 0.06 - 0.08 mm of stock is left, and after tool adjustment, finish machining is completed within one machining step (program segment) (the G04 program code pause cannot be used, otherwise surface defects will appear on the sealing teeth), which solves the problem of excessive roughness of the surface finish of small sealing teeth with a diameter of Φ2.1 - Φ4.1.

[0030] 3. The tooling of the present invention has high reliability, accurate product positioning, can achieve rapid loading and unloading, and significantly shortens the product alignment time from the previous 10 minutes to the current 2 minutes. After aligning the first product, it is not necessary to align each product during mass production; compared with the traditional combined fixture, the maximum rotation speed can be increased from 800 r / min to 3000 r / min, and the single-piece processing time is shortened from 25 minutes to 10 minutes, greatly improving production efficiency.

[0031] 4. The problem of tool breakage is solved, there is no need to replace the tool, and tool setting during the process is avoided.

[0032] 5. This tooling has strong versatility, a wide range of applications, and is convenient for loading and unloading. It can be installed in the three-jaw chucks or cylindrical clamping cans of most machine tools.

[0033] 6. It creates economic benefits, reduces the usage cost of combined fixtures, and saves tooling costs. About 2,000 yuan of cost funds can be saved for every 100 products.

[0034] In summary, through the self-made tooling, increasing the rotation speed, and improving the feed route, the aqueous solution of the machine tool can directly replace the manual brushing method of carbon tetrachloride + lard, solving the problem of time-consuming manual operation, solving the problem of tool breakage in the processing of small sealed cavities, improving production efficiency, and saving cost funds. Brief Description of the Drawings

[0035] Figure 1 It is an assembly structure diagram, where 1 is the tooling body, 2 is the product, 3 is the cover plate, and 4 is the bolt;

[0036] Figure 2 It is a product drawing;

[0037] Figure 3 It is the main dimension drawing of the product;

[0038] Figure 4 It is a partial enlarged view of the side sealed cavity of the product;

[0039] Figure 5 It is a tooling drawing;

[0040] Figure 6 It is a supplementary 3D drawing of the tooling;

[0041] Figure 7 It is the machining route drawing of the sealing tooth (60° end face annular groove) ΦE;

[0042] Figure 8 It is a tool drawing of the sealing tooth. Detailed Embodiments

[0043] The present invention will be further described below in conjunction with the embodiments.

[0044] A processing method for a small sealing cavity of a corrosion-resistant soft magnetic alloy product, in which the tooling body uses the nesting principle to nest the product on the tooling while ensuring the positional tolerance requirements of the product; the main processing methods include: tool selection and sealing surface processing route selection. The main processing steps are as follows:

[0045] Step 1: Rough machine the inner hole, drill and bore the inner hole of the product;

[0046] The parts to be processed in the present invention are such as Figures 1-3 the threaded hole on the side of the product as described above. The bottom of the threaded hole is a groove, and the bottom surface of the groove is a sealing surface. A small sealing cavity, i.e., a sealing tooth ( Figure 4 ) needs to be processed on the sealing surface. P is the distance between the axis of the threaded hole and the end face, which is a design value.

[0047] The present invention needs to rely on the tooling to adapt to the product size. High rotational speed can be set to improve the surface roughness of the product and improve the processing efficiency; the product is nested in the tooling by the profiling method, so that the threaded inner cavity to be processed faces outward, and the central axis of the inner cavity of the product is coaxial with the outer circle central axis of the tooling (clamping part), effectively ensuring the positional tolerance of the product. The protruding part of the product forms a key and groove fit with the tooling, and the fit accuracy is high; at the same time, the width G mm (G width is 8 - 10 mm) of the end face convex part of the product threaded hole is clamped in the tooling groove, which can limit the freedom of the left and right displacement of the product and reduce the time for aligning the product;

[0048] The tooling described in the present invention includes a tooling body 1 and a cover plate 3, as Figure 5 、 6 shown. One end of the tooling body is a clamping part, and the other end is provided with an installation plane. A keyway is arranged on the installation plane, and the keyway matches the lower end face of the product to be processed. The product 2 is nested on the installation plane by the nesting principle and the machining surface to be processed is exposed on the side of the installation plane. The upper end of the product is fixed to the tooling body through a cover plate fastener (bolt 4);

[0049] The workpiece material of the present invention is a corrosion-resistant soft magnetic alloy Cr17NiTi material, and its performance characteristics are good plasticity and easy tool sticking during cutting. Therefore, the tool needs to be ground sharp, the rake angle of the tool is in the range of 10° to 15°, and at the same time, a circular chip evacuation groove is ground; the tool material should not be too hard, and the hardness value should be selected as HRC55 to 65, and it should have a certain toughness. The tool grade can be selected as the S type tool for nickel and titanium alloys; when selecting the drilling tool, the drill bit and center drill should use high-speed steel materials to avoid tool breakage during processing.

[0050] Step 2: Rough machine the inner groove: The method of multiple tool feeds and frequent tool retractions should be adopted, and the tool feeds in layers. Pause with the program code G04 in the middle, blow away the chips with low-pressure air, and the depth of cut ≤ 0.3 mm to avoid chip entanglement and tool breakage;

[0051] Step 3: Process M(F)×0.5 thread (F range is 5-6mm), S is the outer step hole diameter, the design value is 7-8mm: To avoid chip entanglement and tool breakage, it can be processed in two layers, and G04 is used to stop and blow chips in the middle;

[0052] 3.1 The first layer of rough machining removes 0.4mm of excess, and the depth of each back cutting decreases from 0.2 to 0.1mm;

[0053] 3.2 The second layer of finishing is 0.15mm in excess, and the cutting depth is 0.05mm each time;

[0054] 3.3 After finishing the thread, use a boring tool to remove the first burr.

[0055] Step 4: Sealing surface processing, such as Figure 7 As shown:

[0056] 4.1 Use a small boring tool to process the bottom end of the sealing surface and leave a 0.03mm margin to avoid scratches and roughness on the bottom end surface;

[0057] 4.2 Calling Figure 8 As shown, the sealing tooth (60° end face annular groove) tool is used to process ΦE, with a speed of 2000 to 2200r / min. According to the tool path diagram, the rough machining feed rate is 0.02 to 0.03mm / r, and a finishing allowance of 0.06 to 0.08mm is left. The tool is quickly retracted by 0.3 to 0.5mm in the middle, and the finishing feed rate is 0.01 to 0.02mm / r. The tool is fed to a depth of 0.3mm (the specific depth is determined by the product design size), and G04 is not used for pause.

[0058] 4.3 After the sealing ruler is processed, the small boring cutter and the inner groove cutter are respectively used to feed the sealing tooth diameter ΦE, the size range is Φ2.1~Φ4.1, and the depth is fed to the final size. The small boring cutter cuts along the inner ring of the sealing tooth to the minimum diameter Φ0.5~Φ1, and the inner groove cutter cuts along the outer ring of the sealing tooth to the groove diameter Φ5.3~Φ6.3. Remove the final excess and sealing tooth burrs.

[0059] When machining small diameter sealing teeth (60° end face annular groove) of Cr17NiTi material, leave a margin of 0.06 to 0.08 mm, and complete the finishing in one step (program segment) after adjusting the tool (program code G04 cannot be used to pause, otherwise the sealing teeth will have surface defects). This can solve the problem of excessive surface roughness of small sealing teeth of Φ2.1 to 4.1.

[0060] Since the invention uses a self-made tooling, the rotation speed can be increased to 2000 to 3000 r / min. At the same time, layered processing is selected when processing the bottom end face of the inner cavity seal, and the machine tool has its own cooling system, which can solve the problem of excessive roughness of the bottom end face and improve the processing efficiency.

[0061] Step 5: Finish machining the inner hole and the groove. Use a boring tool and an internal grooving tool to finish machining the dimensions of the inner hole and the groove respectively.

[0062] Embodiment

[0063] A processing method for a small sealed cavity of a corrosion-resistant soft magnetic alloy product is as follows:

[0064] 1. Manufacture the tooling.

[0065] Using a machining center, machine the product tooling according to the tooling drawing, ensuring that the total runout of the machined part of the tooling relative to its own central axis is within 0.01 mm. At the same time, ensure the accuracy of the keyway width value is G±0.01 mm, so that the product can be tightly nested in the tooling. There are threaded holes M(K)*1 on the tooling that can cooperate with bolts 4 (as shown in the attachment Figure 1 ), and the fastening bolts can fix the product. After machining, it is necessary to detect the position accuracy of the first-piece product. After aligning the first piece, it is no longer necessary to repeat the alignment for subsequent pieces.

[0066] 2. Select the cutting tools.

[0067] 2.1 The basic hole of the internal thread M(F) of the product is relatively small, so a cutting tool with a diameter of Φ4.5 is selected when choosing the cutting tool;

[0068] 2.2 Since the product needs to machine the bottom end face of the threaded hole (and there is a Φ1 small hole on the bottom end face), a boring tool with a diameter of Φ3 is selected for the boring tool passing through the bottom end face;

[0069] 2.3 The workpiece material is a corrosion-resistant soft magnetic alloy Cr17NiTi material, and its performance characteristics are good plasticity and easy tool sticking during cutting. Therefore, the cutting tool should be sharpened with a cutting edge angle of 15°, and at the same time, a circular chip groove should be ground.

[0070] Note that the cutting tool material should not be too hard. A hardness value of HRC60 should be selected, and it should have a certain toughness. The tool grade is selected as S-type tool;

[0071] 2.4 The following is an example of tool requisition:

[0072] ① For the boring tool, an imported tool bar of Kyocera series with a diameter of Φ4.5 can be selected;

[0073] ② For the internal grooving tool, select a Sandvik Φ4 tool bar with a main cutting edge width of 1.2 mm;

[0074] ③ For the tool for the sealing teeth (60° end face annular groove), a Φ4 milling cutter bar can be ground. Note that the back angle should not be ground too large, otherwise it is easy to break;

[0075] ④ For the internal threading tool, a black quenched tool is more suitable (the red-brown quenched hardness is too high and the tool is easy to break);

[0076] ⑤ For the rest of the rough turning tools, use a Φ4 alloy bar for grinding;

[0077] 2.5 Selection of drilling tools: For drill bits and center drills, high-speed steel materials should be used to avoid tool breakage during processing. A Φ5.2mm drill bit is used for drilling.

[0078] 3. Process according to the processing flow.

[0079] The main processing steps are as follows:

[0080] Step 1: Rough machine the inner hole, drill and bore the inner hole of the product;

[0081] Step 2: Rough machine the inner groove: The method of multiple feeds and frequent tool retractions should be adopted, with layered feeds. Pause with the program code G04 in the middle, blow away the chips with low-pressure air, and the depth of cut is 0.2mm to avoid chip entanglement and tool breakage;

[0082] Step 3: Machine the M6×0.5 thread: To avoid chip entanglement and tool breakage, it can be machined in two layers, and pause and blow chips with G04 in the middle;

[0083] 3.1 In the first layer of rough machining, remove 0.4mm of stock, and the depth of cut per pass decreases from 0.2 to 0.1mm;

[0084] 3.2 In the second layer of finish machining, remove 0.15mm of stock, and the depth of cut per pass is 0.05mm;

[0085] 3.3 After finishing the thread machining, a boring tool should be used to remove the burrs of the first thread.

[0086] Step 4: Seal surface machining:

[0087] 4.1 Use a small boring tool to machine the bottom end face of the seal surface, leaving 0.03mm of stock to avoid scratches and large roughness on the bottom end face;

[0088] 4.2 The machining route diagram of the seal teeth (60° end face annular groove) ΦE is as Figure 7 shown. Call the seal tooth tool to machine ΦE, with a rotational speed of 2200r / min. According to the feed route diagram, the feed rate for rough machining is 0.03mm / r, leaving 0.08mm of finish machining stock. Rapid retract 0.3mm in the middle, and the feed rate for finish machining is 0.02mm / r. Feed to the final depth of 0.3mm without using G04 pause.

[0089] 4.3 After machining the seal teeth, call the small boring tool and the inner groove tool respectively, feed to the diameter of the seal teeth Φ4.1, and feed to the final depth. The small boring tool feeds along the inner circle of the seal teeth to the minimum diameter Φ1, and the inner groove tool feeds along the outer circle of the seal teeth towards the groove diameter Φ6.3. Remove the final stock and the burrs of the seal teeth.

[0090] Step 5: Finish machine the inner hole and groove, and use a boring tool and an inner groove tool to finish machine the inner hole and groove dimensions respectively.

[0091] The processing method of this achievement is applicable to other products with similar shapes at the same time, and the processing method is applicable to the processing of products made of soft magnetic alloy materials with different outer shapes but similar inner cavities.

[0092] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A processing method for a small sealed cavity of a corrosion-resistant soft magnetic alloy product. The side of the soft magnetic alloy product has a threaded hole to be processed. The bottom of the threaded hole is a groove, the bottom of the groove is a sealing surface, and a sealed cavity is arranged on the sealing surface. It is characterized in that Including: Manufacturing and processing tooling; the tooling includes a tooling body and a cover plate. One end of the tooling body is a clamping part, and the other end is provided with an installation plane. A keyway is arranged on the installation plane, and the keyway matches the lower end face of the product to be processed. The product is sleeved on the installation plane by the sleeving principle and the machining surface to be processed is exposed on the side of the installation plane. The upper end of the product is fixedly connected to the tooling body through a cover plate fastener; Select a tool according to the threaded hole of the product to be processed, and drill and bore the product for rough machining of the threaded hole; Rough machining the groove; Machining the threaded hole in layers, completing the finish machining of the threaded hole and removing the burr of the first thread; Machining the sealing surface, leaving a margin on the sealing surface; Using a sealing tooth cutter to machine the sealing cavity, that is, the sealing teeth, with a rotational speed of 2000 to 2200 r / min, a rough machining feed rate of 0.02 to 0.03 mm / r, leaving a finish machining margin of 0.06 to 0.08 mm; first machine to a depth of 0.15 ± 0.05, retract the tool by 0.3 to 0.5 mm, and then machine to a depth of 0.22 to 0.24 mm; the finish machining feed rate is 0.01 to 0.02 mm / r, and feed to the theoretical depth of the sealing cavity; Using a boring cutter to feed along the inner circle of the sealing teeth towards the minimum diameter, and an inner groove cutter to feed along the outer circle of the sealing teeth towards the groove diameter, removing the remaining margin on the final hole bottom end face and the burr of the sealing teeth; Using a boring cutter and an inner groove cutter to finish machine the dimensions of the threaded hole and the groove.

2. The method according to claim 1, wherein: The rough machining depth is 0.15 ± 0.05, and use the CNC G0 command to retract the tool by 0.3 to 0.5 mm; the CNC G04 command is not allowed to pause during the finish machining process.

3. The method according to claim 1, wherein: Using a machining center equipment to machine the product tooling, ensuring that after the product is installed on the machined part of the tooling, the total runout of the central axis of the product relative to the central axis of the tooling is within 0.01 mm, and at the same time ensuring the accuracy of the keyway width value is G ± 0.01 mm, where G is the width of the end face convex part of the product threaded hole.

4. The method according to claim 3, characterized in that: Detect and align the position of the product tooling axis with respect to the first-piece product, and subsequent batch processing products do not need to be realigned repeatedly.

5. The method according to claim 1, wherein: During the rough machining of the groove, adopt a layered feed method, pause for two feed intervals, blow the chips with gas, and the back engagement of the cutter is ≤ 0.3 mm.

6. The method according to claim 1, wherein: Threaded hole machining Including: The first layer of rough machining removes a margin of 0.3 to 0.4 mm, and the back engagement of the cutter decreases from 0.2 to 0.15 mm to 0.1 to 0.05 mm each time; The second layer of finish machining removes the remaining margin, and the depth of cut each time is 0.05 to 0.03 mm; After finish machining the thread, a boring cutter should be used to remove the burr of the first thread.

7. The method according to claim 1, characterized in that: Use a boring cutter to machine the bottom end face of the sealing surface, leaving a margin of 0.03 to 0.01 mm.

8. The method according to claim 1, characterized in that: The selected inner groove cutter, boring cutter, and sealing tooth cutter have a tool rake angle in the range of 10° to 15°, a hardness value of HRC55 to 65, and a round-arc chip-breaking groove is ground.

9. The method according to claim 1, characterized in that: The sealing teeth are 60° end face annular grooves, the center diameter of the sealing teeth is Φ2.1 to 4.1 mm, and the product material is Cr17NiTi.

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