Cladding process for corrosion-resistant layer of inner runner of bearing cylinder for energy recovery unit

Abstract

A cladding process for a corrosion-resistant layer of an inner runner of a bearing cylinder for an energy recovery unit comprises the following steps: casting the bearing cylinder by adopting cast steel, roughly machining an outer circle, an inner hole, a taper hole and various stages of stationary blade holes of the bearing cylinder, and carrying out first heat treatment to relieve stress after rough machining to obtain a bearing cylinder blank; carrying out cladding, secondary heat treatment and secondary flaw detection on the rear half section or the whole runner of the bearing cylinder blank after carrying out semi-finish machining on the cladding surface of the bearing cylinder blank and carrying out primary flaw detection to obtain a bearing cylinder intermediate; and finally, the bearing cylinder intermediate is subjected to outer circle semi-finish machining, stationary blade hole machining and inner flow channel machining, third-time flaw detection is carried out, whether repair welding is carried out or not is determined according to the flaw detection result, finish machining is carried out after repair welding is completed, and the corrosion-resistant bearing cylinder for the energy recovery unit is obtained. Cast steel is adopted, the corrosion-resistant layer is cladded on the rear half section of the bearing cylinder or the whole runner to achieve corrosion prevention, and the method has the advantages of being low in cost and good in protection effect.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace gas residual pressure recovery turbine power generation device (TRT), and in particular to a corrosion-resistant layer cladding process for a flow channel in a bearing cylinder of an energy recovery unit. Background Art

[0002] The blast furnace gas waste pressure recovery turbine power generation device (TRT) is a secondary energy recovery device that converts the internal energy of the high-temperature and high-pressure gas generated by the blast furnace into mechanical energy or electrical energy to achieve energy recycling.

[0003] With the improvement of blast furnace smelting technology, the temperature of coal gas entering the TRT unit gradually decreased from 120-150°C to 90-120°C, resulting in condensation of gas in the second half of the TRT unit to produce acidic liquid, which is rich in Cl - 、SO4 2- Plasma media seriously corrodes the original bearing cylinder material (cast steel or cast iron), affecting the life of the unit. The current production method is to replace the integral bearing cylinder with cast stainless steel to increase the overall life of the unit; but the current measures have the following disadvantages: 1) The overall use of cast stainless steel has high manufacturing costs, and corrosion is prone to occur in the rear section of the unit, so overall casting of stainless steel is relatively wasteful; 2) Stainless steel generally has good corrosion resistance to H2SO4, and is prone to intergranular corrosion in HCl environment, so it has poor corrosion resistance in the acidic liquid formed by condensation of high-temperature coal gas. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a process for cladding a corrosion-resistant layer in the flow channel of a bearing cylinder for an energy recovery unit. The substrate is made of cast steel, and a layer of corrosion-resistant layer is clad on the rear half of the bearing cylinder or the entire flow channel to achieve corrosion protection, which has the advantages of low cost and good protection effect.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A welding process for a corrosion-resistant layer of a flow channel in a bearing cylinder for an energy recovery unit comprises the following steps:

[0007] Step 1), using cast steel to complete the casting of the bearing cylinder, rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, and after the rough machining is completed, performing the first heat treatment to eliminate stress to obtain a bearing cylinder blank;

[0008] Step 2), the bearing cylinder blank is semi-finished and clad, and the first flaw detection is performed. After ensuring that the clad surface has no defects exceeding the standard, the rear half of the bearing cylinder blank or the entire flow channel is clad, and a second heat treatment is performed to eliminate stress and a second flaw detection is performed to obtain a bearing cylinder intermediate;

[0009] Step 3), semi-finishing outer circle, stationary blade hole and inner flow channel processing are performed on the intermediate body of the bearing cylinder, followed by a third flaw detection, and then finishing processing is performed after completion to obtain a corrosion-resistant bearing cylinder for the energy recovery unit.

[0010] In the step 1), when rough machining the outer circle, inner hole, tapered hole and various levels of stationary blade holes of the bearing cylinder, a single side margin of 5-10mm is left, and a single side margin of 5-10mm is left on both end surfaces of the bearing cylinder. The inner hole at the right end surface with a margin of 10mm is machined into a straight hole.

[0011] In the step 2) of semi-finishing, the inner wall cladding area is first processed to the finishing size, and then the cladding layer thickness is further processed downward, and finally further processed downward by 2 to 3 mm.

[0012] The cladding in step 2) is specifically as follows:

[0013] 2.1) Surface pretreatment: using an organic solvent to remove oil from the surface of the cylinder blank; the organic solvent is alcohol or acetone;

[0014] 2.2) The cladding material is made of high-temperature alloy powder, the composition of which satisfies Cr: 20-23%, Co: 0.5-1%, Mo: 8-10%, Nb: 3.15-4.15%, C: ≤0.1%, Fe≤5%, Ni: the rest;

[0015] Cladding parameter control: according to the requirements of the cladding layer thickness, set the parameters of laser power, scanning speed, powder feeding speed, overlap rate, and spot diameter; after the cladding is completed, the thickness of the cladding layer is 0.5-2mm greater than the final required thickness, and the surface of the bearing cylinder is overall flat;

[0016] Deformation control measures:

[0017] (1) Segmental cladding: Cladding is performed in sections according to the size of the cladding area. Cladding is performed in a circular manner from right to left or symmetrically from the middle to the outside to ensure that the unclad parts are not overheated.

[0018] (2) For base coating, the laser power is controlled to 1700-1900w and the scanning speed is 15-25mm / s to reduce heat input;

[0019] (3) An annular anti-deformation tooling is set on the right periphery of the cylinder, and the unclad part inside is cross-supported by steel pipes at the center plane;

[0020] The cladding parameters in step 2.2) are: laser power: 1500-2400w; overlap rate: ≥40%; powder feeding speed: 15-30g / min; scanning speed: 15-25mm / s, and spot diameter 2-4mm.

[0021] In the step 2), a 7-axis robot arm with an arm span of 1.7 m is used for cladding, and its control accuracy is not less than 0.03 mm.

[0022] The process of the second heat treatment to eliminate stress in step 2) is: heat preservation at 600-640°C for 1-3h, cooling to 150-200°C and then cooling in the furnace.

[0023] In the step 2), the cladding metal is multi-layer cladding. Each cladding layer of metal needs to be polished and a second flaw detection is performed using a penetration method. The requirements of NB / T 47013.5 are required, and crack defects are not allowed. Level II is qualified and circular defects are required to be ≤Φ3mm.

[0024] In the step 3), the cladding layer after fine machining meets the design size requirements and the local thinning amount is not less than 10%.

[0025] If the third flaw detection result in step 3) is unqualified, the defects are repaired by welding using the original cladding method and cladding parameters, or by argon arc welding.

[0026] In step 3), after the upper and lower middle surfaces of the middle cylinder are exposed to light and flat, the upper cylinder and the lower cylinder are buckled on the workbench respectively, aligned according to the large end surfaces, and the upper cylinder is used as a reference to make a table, and the difference is marked at the corresponding point of the lower cylinder for alignment during machining.

[0027] In the step 3), the inner hole is clad as required, with a single-side margin of 0.3-0.5 mm. Before machining the inner hole, the cutting parameters are optimized, including a feed rate of 0.4-0.6 mm and a rotation speed of 25-30 r / min, to ensure that the size and roughness of the inner hole meet the requirements.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) Since the present invention adopts the support cylinder casting, compared with the overall selection of cast stainless steel, its manufacturing cost is greatly reduced;

[0030] 2) Since the present invention clads the rear half of the cylinder blank or the entire flow channel to prepare a corrosion-resistant layer, compared with the existing stainless steel with better corrosion resistance to H2SO4 and poor corrosion resistance in HCl environment, the present invention has a good protective effect, especially in Cl-containing environments. - Better corrosion resistance in acidic environment;

[0031] 3) Due to the cladding parameter control of the present invention: according to the cladding layer thickness requirements, the parameters of laser power, scanning speed, powder feeding speed, overlap rate, and spot diameter are set; after the cladding is completed, the cladding layer thickness should be greater than the final required thickness by 0.5-2mm, so the surface of the bearing cylinder is flat as a whole;

[0032] 4) Since the cladding of the present invention adopts deformation control measures, the cladding is carried out in sections according to the size of the cladding area, and the cladding is carried out in a circular form from right to left to ensure that the unclad parts are not overheated; the laser power of the base layer is controlled to be 1700-1900w, and the scanning speed is 15-25mm / s to reduce the heat input; a ring-shaped anti-deformation tool is set on the outer periphery of the right side of the support cylinder, and the internal unclad parts are cross-supported by steel pipes at the middle dividing surface position, so the cladding deformation is small and the cladding quality is good;

[0033] 5) Since the cladding metal of the present invention is multi-layer cladding, each cladding layer of metal needs to be polished and the surface of the cladding metal layer needs to be inspected for the second time by penetration method, which is required to meet the requirements of NB / T 47013.5, and crack defects are not allowed. Level II is qualified and circular defects are required to be ≤Φ3mm, so the cladding quality is good;

[0034] 6) Since the present invention uses a 7-axis mechanical arm with an arm span of 1.7m for cladding, its control accuracy is not less than 0.03mm, so the cladding accuracy is high;

[0035] 7) Since the present invention clads the inner hole as required, leaves a single-side margin of 0.3-0.5 mm, then selects a tool and optimizes cutting parameters to ensure that the size and roughness of the finely machined inner hole meet the requirements, the dimensional accuracy is high.

[0036] In summary, the substrate of the present invention is made of cast steel, and a corrosion-resistant layer is clad on the rear half of the cylinder or the entire flow channel to achieve corrosion protection, which has the advantages of low cost and good protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of an embodiment of the present invention.

[0038] Figure 2 This is a structural diagram of the supporting cylinder of Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The present invention is described in detail below in conjunction with embodiments and drawings.

[0040] Example 1, reference Figure 1 A welding process for a corrosion-resistant layer of a flow channel in a bearing cylinder for an energy recovery unit comprises the following steps:

[0041] Step 1), using cast steel ZG200-400 to complete the casting of the bearing cylinder, rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, and after the rough machining is completed, the first heat treatment is performed to eliminate stress to obtain the bearing cylinder blank;

[0042] In this embodiment, when rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, a 10mm margin is left on each side, and a 10mm margin is left on each side of both end surfaces of the bearing cylinder. The inner hole at the 10mm margin on the right end surface is machined as a straight hole for subsequent benchmark alignment;

[0043] Step 2), the bearing cylinder blank is semi-finished and clad, and the first flaw detection is performed. After ensuring that the clad surface has no defects exceeding the standard, the rear half of the bearing cylinder blank or the entire flow channel is clad, and the second heat treatment is completed to eliminate stress and the second flaw detection is performed to obtain the bearing cylinder intermediate;

[0044] In the semi-finishing process of this embodiment, the cladding area is first processed to the finishing size, and then the cladding layer thickness is further processed downward by 5 mm, and finally by 3 mm. A 7-axis robot arm with a 1.7 m arm span is used for cladding, and its control accuracy is not less than 0.03 mm.

[0045] The specific cladding is:

[0046] 2.1) Surface pretreatment: Use alcohol to degrease the surface of the cylinder blank, and then perform cladding as soon as possible after degreasing;

[0047] 2.2) The cladding material is Ni-based high-temperature alloy powder, and the measured composition is Cr: 21.56%, Co: 0.76%, Mo: 8.2%, Nb: 3.25%, C: 0.008%, Fe: 3.0%, Ni: the rest;

[0048] Cladding parameter control: according to the requirements of the cladding layer thickness, set the laser power, scanning speed, powder feeding speed, overlap rate, spot diameter and other parameters; to ensure the final thickness of the cladding layer, after the cladding is completed, the thickness of the cladding layer should be greater than the final required thickness by 0.5mm, and there should be no gullies on the surface of the cylinder, and the whole should be flat;

[0049] Deformation control measures:

[0050] (1) Segmental cladding: Cladding is performed in sections according to the size of the cladding area, and cladding is performed in a circular manner from right to left to ensure that the unclad parts are not overheated;

[0051] (2) The laser power of the base layer is controlled to 1800w and the scanning speed is 20mm / s to reduce the heat input;

[0052] (3) An annular anti-deformation tooling is set on the right periphery of the cylinder, and the unclad part inside is cross-supported by steel pipes at the center plane;

[0053] The cladding parameters in step 2.2) are: laser power: 2000w; overlap rate: ≥40%; powder feeding speed: 20g / min; scanning speed: 23mm / s; spot diameter 3mm;

[0054] The second heat treatment process is: keep at 620℃ for 2h, cool to 200℃ and then cool in the furnace;

[0055] The cladding metal is multi-layer cladding. Each layer of cladding metal needs to be polished and inspected by penetration. The inspection is carried out according to the NB / T 47013 standard color flaw detection. Crack defects are not allowed. Level II is qualified and circular defects are required to be ≤Φ3mm. If defects are detected during the process, they will be repaired at any time.

[0056] Step 3), semi-finishing the outer circle, the stationary blade hole and the inner flow channel of the intermediate body of the bearing cylinder, and then performing a third flaw detection, and deciding whether to repair welding according to the flaw detection results, and then performing fine processing after completion to obtain a corrosion-resistant bearing cylinder for the energy recovery unit;

[0057] In this embodiment, the repair welding is performed on the defects according to the cladding method and cladding parameters. When the bearing cylinder is disassembled, it is difficult to repair the defects by the original process, so the argon arc welding method is used to repair the defects locally; the local thinning amount of the cladding layer after fine processing is not less than 10%;

[0058] Reference Figure 2 After the upper and lower middle surfaces of the cylinder in this embodiment are exposed to light and flat, the upper cylinder and the lower cylinder are buckled on the workbench respectively, and the large end surfaces are aligned. The upper cylinder is used as a reference to make a table, and the difference is marked on the corresponding point of the lower cylinder for alignment in the lathe processing;

[0059] Cladding the inner hole as required, leaving a single-side allowance of 0.5mm, optimizing the cutting parameters before machining the inner hole, including feed rate of 0.5mm, speed of 28r / min, measuring the inner hole size and roughness after finishing, ensuring that the finished inner hole size and roughness meet the requirements;

[0060] The anti-corrosion performance test of this embodiment: the sample was corroded by 5% H2SO4 for 1 week, with an average corrosion rate of 0.20g / year, a thinning amount of the corrosion-resistant layer of 0.87mm / year, and no intergranular corrosion occurred; the sample was corroded by 5% HCl for 1 week, with an average corrosion rate of 0.81g / year, a thinning amount of the corrosion-resistant layer of 0.35mm / year, and no intergranular corrosion occurred.

[0061] Example 2, the cladding parameters of step 2) of Example 1 are changed to: laser power: 1500w; overlap rate: ≥50%; powder feeding speed: 15g / min; scanning speed: 15mm / s; spot diameter 2mm; the second heat treatment process is changed to: 600℃ insulation for 1h, furnace cooling to 150℃ and then furnace cooling; other steps remain unchanged, and the cladding layer thickness is 2mm.

[0062] The anti-corrosion performance test of this embodiment: the sample was corroded by 5% H2SO4 for 1 week, with an average corrosion rate of 0.28g / year, a thinning amount of the corrosion-resistant layer of 0.70mm / year, and no intergranular corrosion occurred; the sample was corroded by 5% HCl for 1 week, with an average corrosion rate of 0.46g / year, a thinning amount of the corrosion-resistant layer of 0.35mm / year, and no intergranular corrosion occurred.

[0063] Example 3, the cladding parameters of step 2) of Example 1 are changed to: laser power: 2400w; overlap rate: ≥40%; powder feeding speed: 30g / min; scanning speed: 25mm / s; spot diameter 4mm; the second heat treatment process is changed to: 640℃ insulation for 3h, furnace cooling to 180℃ and then furnace cooling; other steps remain unchanged.

[0064] The anti-corrosion performance test of this embodiment: the sample was corroded by 5% HCl for 1 week, the average corrosion rate was 0.81g / year, the thinning amount of the corrosion-resistant layer was 0.35mm / year, and no intergranular corrosion occurred.

Claims

1. A welding process for the corrosion-resistant layer of the inner flow channel of a bearing cylinder for an energy recovery unit, characterized in that: The following steps are involved: Step 1), using cast steel to complete the casting of the bearing cylinder, rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, and after the rough machining is completed, the first heat treatment is performed to eliminate stress to obtain a bearing cylinder blank; Step 2), the bearing cylinder blank is semi-finished and clad, and the first flaw detection is performed. After ensuring that the clad surface has no defects exceeding the standard, the rear half of the bearing cylinder blank or the entire flow channel is clad, and the second heat treatment is completed to eliminate stress and the second flaw detection is performed to obtain the bearing cylinder intermediate; Step 3), semi-finishing outer circle, stationary blade hole and inner flow channel processing are performed on the intermediate body of the bearing cylinder, followed by a third flaw detection, and then finishing processing is performed after completion to obtain a corrosion-resistant bearing cylinder for the energy recovery unit.

2. The method according to claim 1, characterized in that the cladding in step 2) is specifically: 2.1) Surface pretreatment: using an organic solvent to remove oil from the surface of the cylinder blank; the organic solvent is alcohol or acetone; 2.2) The cladding material is made of high-temperature alloy powder, the composition of which satisfies Cr: 20-23%, Co: 0.5-1%, Mo: 8-10%, Nb: 3.15-4.15%, C: ≤0.1%, Fe≤5%, Ni: the rest; Cladding parameter control: according to the requirements of the cladding layer thickness, set the parameters of laser power, scanning speed, powder feeding speed, overlap rate, and spot diameter; after the cladding is completed, the thickness of the cladding layer is 0.5-2mm greater than the final required thickness, and the surface of the bearing cylinder is overall flat; Deformation control measures: (1) Segmental cladding: Cladding is performed in sections according to the size of the cladding area. Cladding is performed in a circular manner from right to left or symmetrically from the middle to the outside to ensure that the unclad parts are not overheated. (2) For base coating, the laser power is controlled to 1700-1900w and the scanning speed is 15-25mm / s to reduce heat input; (3) An annular anti-deformation tooling is set on the outer periphery of the right side of the supporting cylinder, and the internal unclad part is cross-supported by a steel pipe at the center dividing surface.

3. The method according to claim 2, characterized in that The cladding parameters in step 2.2) are: laser power: 1500-2400w; overlap rate: ≥40%; powder feeding speed: 15-30g / min; scanning speed: 15-25mm / s, and spot diameter 2-4mm.

4. The method according to claim 2, characterized in that: In the step 2), the cladding metal is multi-layer cladding. Each cladding layer of metal needs to be polished and a second flaw detection is performed using a penetration method. The requirements of NB / T 47013.5 are required, and crack defects are not allowed. Level II is qualified and circular defects are required to be ≤Φ3mm.

5. The method according to claim 1, characterized in that: In the step 2), a 7-axis robot arm with an arm span of 1.7 m is used for cladding, and its control accuracy is not less than 0.03 mm.

6. The method according to claim 1, characterized in that: The second heat treatment stress relief process in step 2) is as follows: heat preservation at 600-640°C for 1-3h, followed by furnace cooling to 150-200°C and then furnace cooling.

7. The method according to claim 1, characterized in that: In the step 3), after fine machining, the cladding layer meets the design size requirements and the local thinning amount is not less than 10%; if the third flaw detection result in step 3) is unqualified, the defects are repaired by welding using the original cladding method and cladding parameters, or by argon arc welding.

8. The method according to claim 1, characterized in that: In step 3), after the upper and lower middle surfaces of the middle cylinder are exposed to light and flat, the upper cylinder and the lower cylinder are buckled on the workbench respectively, aligned according to the large end surfaces, and the upper cylinder is used as a reference to make a table, and the difference is marked at the corresponding point of the lower cylinder for alignment during machining.

9. The method according to claim 1, characterized in that: In the step 3), the inner hole is clad as required, with a single-side margin of 0.3-0.5 mm. Before machining the inner hole, the cutting parameters are optimized, including a feed rate of 0.4-0.6 mm and a rotation speed of 25-30 r / min, to ensure that the size and roughness of the inner hole meet the requirements.

10. A welding process for the corrosion-resistant layer of the inner flow channel of a bearing cylinder for an energy recovery unit according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1), using cast steel ZG200-400 to complete the casting of the bearing cylinder, rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, and after the rough machining is completed, the first heat treatment is performed to eliminate stress to obtain the bearing cylinder blank; When rough machining the outer circle, inner hole, tapered hole, and various levels of stationary blade holes of the bearing cylinder, a 10mm allowance is left on each side, and a 10mm allowance is left on each side of both ends of the bearing cylinder. The inner hole at the 10mm allowance on the right end face is machined as a straight hole for subsequent benchmark alignment; Step 2), the bearing cylinder blank is semi-finished and clad, and the first flaw detection is performed. After ensuring that the clad surface has no defects exceeding the standard, the rear half of the bearing cylinder blank or the entire flow channel is clad, and the second heat treatment is completed to eliminate stress and the second flaw detection is performed to obtain the bearing cylinder intermediate; During semi-finishing, the cladding area is first machined to the finishing size, and then the cladding layer thickness is further machined downward by 5mm, and finally by 3mm. A 7-axis robotic arm with a 1.7m arm span is used for cladding, and its control accuracy is not less than 0.03mm. The specific cladding is: 2.1) Surface pretreatment: Use alcohol to degrease the surface of the cylinder blank, and then perform cladding as soon as possible after degreasing; 2.2) The cladding material is Ni-based high-temperature alloy powder, and the measured composition is Cr: 21.56%, Co: 0.76%, Mo: 8.2%, Nb: 3.25%, C: 0.008%, Fe: 3.0%, Ni: the rest; Cladding parameter control: according to the requirements of the cladding layer thickness, set the parameters of laser power, scanning speed, powder feeding speed, overlap rate, and spot diameter; to ensure the final thickness of the cladding layer, after the cladding is completed, the thickness of the cladding layer should be greater than the final required thickness by 0.5mm, and there should be no gullies on the surface of the cylinder, and the whole should be flat; Deformation control measures: (1) Segmental cladding: Cladding is performed in sections according to the size of the cladding area, and cladding is performed in a circular manner from right to left to ensure that the unclad parts are not overheated; (2) The laser power of the base layer is controlled to 1800w and the scanning speed is 20mm / s to reduce the heat input; (3) An annular anti-deformation tooling is set on the right periphery of the cylinder, and the unclad part inside is cross-supported by steel pipes at the center plane; The cladding parameters in step 2.2) are: laser power: 2000w; overlap rate: ≥40%; powder feeding speed: 20g / min; scanning speed: 23mm / s; spot diameter 3mm; The second heat treatment process is: keep at 620℃ for 2h, cool to 200℃ and then cool in the furnace; The cladding metal is multi-layer cladding. Each layer of cladding metal needs to be polished and inspected by penetration. The inspection is carried out according to the NB / T 47013 standard color flaw detection. Crack defects are not allowed. Level II is qualified and circular defects are required to be ≤Φ3mm. If defects are detected during the process, they will be repaired at any time. Step 3), semi-finishing the outer circle, the stationary blade hole and the inner flow channel of the intermediate body of the bearing cylinder, and then performing a third flaw detection, and deciding whether to repair welding according to the flaw detection results, and then performing fine processing after completion to obtain a corrosion-resistant bearing cylinder for the energy recovery unit; Repair welding is carried out on defects according to the cladding method and cladding parameters. When the cylinder is disassembled, it is difficult to repair the defects by the original process, so argon arc welding is used for local repair welding; the local thinning of the cladding layer after fine processing is not less than 10%; After the upper and lower middle surfaces of the cylinder are exposed to light and flat, buckle the upper and lower cylinders on the workbench respectively, align them according to the large end surfaces, use the upper cylinder as the reference to make a table, and mark the difference at the corresponding point of the lower cylinder for alignment during machining; Cladding the inner hole is carried out as required, with a single-side allowance of 0.5mm. The cutting parameters are optimized before machining the inner hole, with a cutting depth of 0.5mm and a tool speed of 28r / min. After finishing, the inner hole size and roughness are measured to ensure that the finished inner hole size and roughness meet the requirements.

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