Processing method for steel long screw used in electrolyzer of hydrogen production equipment

Abstract

The present invention relates to the technical field of long screw processing, and specifically discloses a processing method for a steel long screw used in an electrolytic cell of a hydrogen production equipment. The specific steps of the method are as follows: Put the steel bar raw material into a heated furnace for conditioning treatment. The conditioning treatment method includes: quenching treatment, high-temperature tempering treatment, cooling to a specified temperature after high-temperature tempering and heat preservation, checking the straightness. If the measured straightness > 4 mm, the steel bar is in a warped state. Use a temperature measuring tool to measure the warped steel bar. When the temperature reaches the straightening temperature, use a straightening device for hot straightening to straighten the straightness of the warped steel bar to 1-2 mm. After straightening, air-cool, and then perform a second supplementary tempering to make the mechanical properties of the steel bar meet the EU CE standard and usage requirements. The processing process of the steel long screw of the present invention is as follows: quenching and straightening process → supplementary tempering process → datum setting process → center rest datum turning process → long screw processing process, which can effectively improve the mechanical properties and straightness of the steel bar.

Description

Technical Field

[0001] The invention belongs to the technical field of long screw processing, and in particular relates to a processing method of a steel long screw for an electrolytic cell of hydrogen production equipment. Background Art

[0002] The electrolyzer is the core of hydrogen production equipment. The electrolyzer usually uses long screws to assemble and connect the pole frame and the end pressure plate. It is an important structural fastener of the electrolyzer and one of the pressure-bearing parts. The reliability of the screw affects the service life of the electrolyzer and is a necessary condition for the electrolyzer to pass CE certification.

[0003] However, when ordinary forged long screws are used as the long screws of electrolytic cells for processing, the screws cannot meet the CE standard of 54J at 0°C during forging, and the plastic elongation strength Rp0.2 cannot be guaranteed at the same time, which seriously affects the life of the electrolytic cell.

[0004] The finished long screw of the electrolytic cell is usually 4-13 meters in length and ∮10-∮68 in outer diameter. Under the premise of meeting the CE mechanical properties, the size requirements must be met, and the following problems usually occur when processing steel long screws: 1. After heat treatment, the bar material does not meet the standard of 54J at 0°C; 2. After heat treatment, the specified plastic extension strength Rp0.2 of the bar material does not reach 850Mpa, resulting in insufficient strength of the long screw, which is easy to cause local bending, elastic failure, and the electrolytic cell cannot be assembled normally. After forced assembly, it will cause serious deformation and cause a major risk of the electrolytic cell falling apart; 3. After heat treatment, the tensile strength of conventional long screws does not reach 950Mpa. Under extreme working conditions, there will be hidden dangers of breakage, resulting in serious damage to the electrolytic cell. bad; 4. After heat treatment, the conventional long screw is seriously warped, with a straightness of more than 4mm, and cannot be machined; 5. After being placed for a period of time, the existing long screw will have internal stress, and the warping deformation will reach 5-8mm, which will make it impossible to assemble; 6. However, when the long screw with released internal stress is turned, the processing efficiency is low, and it takes 3 normal working days to process a screw, and the tool vibration and collision phenomena occur frequently during processing, resulting in serious damage to the tool; 7. The outer diameter runout of the finished screw is 3mm and the straightness is 4mm, so it cannot meet the technical requirements for the required assembly. The screw is bent, and the technical requirements are: the runout is 1mm, and the straightness is 1mm; Therefore, it is urgently needed to invent and design a processing method for a steel long screw for an electrolyzer of hydrogen production equipment to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method for processing a long steel screw for an electrolyzer of hydrogen production equipment, which solves the problems that the material after heat treatment mentioned above does not meet the CE standards and usage requirements, is prone to warping after heat treatment, resulting in great difficulty in processing, is prone to warping and cannot be assembled after being placed for a period of time if the internal stress is not eliminated, is prone to tool vibration and collision during processing, and is also prone to tool damage and low processing efficiency.

[0006] In order to solve the above technical problems, the present invention provides a method for processing a steel long screw for an electrolyzer of hydrogen production equipment, and the specific steps of the method are as follows:

[0007] S1. Put the steel bar raw material into the heated furnace for modulation treatment. The modulation treatment method includes quenching treatment, high temperature tempering treatment, cooling to the specified temperature after high temperature tempering and heat preservation, checking the straightness, and measuring the straightness>4mm, the steel bar is in a warped state. Use a temperature measuring tool to measure the warped steel bar. When the temperature reaches the straightening temperature, use the straightening equipment for heat calibration, and calibrate the straightness of the warped steel bar to 1-2mm. After the straightening is completed, air cool;

[0008] S2. After straightening, the steel bars are air-cooled to room temperature, and the bars are placed in a furnace for secondary tempering to improve the comprehensive mechanical properties of the steel bars and make them meet EU CE standards and usage requirements;

[0009] S3. Use a steel rod as the long axis of the long screw, and randomly select one end of the long axis as the reference end and the other end as the non-reference end. Use a machine tool chuck to clamp the reference end of the long axis, use the reference method to drill a pinhole on the non-reference end of the long axis, and mark the best reference position for setting up the center frame at the same time.

[0010] Turn the long shaft around and clamp the non-reference end with the machine chuck. Install the center frame on the machine tool, use the center frame to support the middle of the long shaft, use the reference method to drill the pinhole at the reference end of the long shaft, and mark the best reference position for setting up the center frame.

[0011] S4. Change the clamping method, change the direction of the long axis, install the first ejector on the ejector seat of the machine tool, clamp a reference calibration tool in the chuck jaws of the machine tool, clamp a second ejector in the chuck jaws and locate it on the inner side of the tool, move the long axis position by adjusting the reference calibration tool, so that the first ejector and the second ejector both support the ejector holes at both ends of the long axis, rotate in the double-top state, perform external turning on the best reference position of the center frame marked, and turn out the outer circle of the long axis, and this position is used as the reference surface of the center frame;

[0012] S5. Move the steady rest to the reference plane of the steady rest, support the long shaft, and perform rough turning of the outer diameter, semi-finish turning of the outer diameter, turning of the non-reference end face, finish turning of the outer diameter, and machining of the threads at both ends of the long shaft on the long shaft, and polish the outer diameter to complete the machining of the long screw, so that the technical parameters of the long screw are within the specified requirements, and test the performance of the long screw.

[0013] Further, the steel bar raw material in S1 is fastener alloy steel that complies with EU Directive 2014 / 68 / EU.

[0014] Further, the quenching treatment in S1: Heat the furnace to 920 ± 50 °C to heat the steel bar raw material, with a heating rate of 50 °C to 200 °C / h, then hold for 1 - 4 hours, and after holding, cool with oil; High-temperature tempering treatment: Heat the temperature to 600 ± 50 °C, hold for 2 - 8 hours, and after holding, air-cool to a temperature of 250 °C ± 20 °C; Control the oil temperature for oil cooling at 20 - 50 °C, and the cooling rate is 50 °C to 200 °C / h.

[0015] Further, the temperature measuring tool in S1 is a temperature gun, and the specified temperature and straightening temperature in S1 are both 250 °C ± 20 °C.

[0016] Further, the normal temperature in S2 is 0 - 30 °C, the secondary tempering temperature is 400 ± 150 °C, and the improved comprehensive mechanical properties in S2 are the strength, hardness, and toughness of the steel bar.

[0017] Further, the method for determining the reference in S3 is as follows: Clamp the reference end or non-reference end of the long shaft with the machine tool chuck, install a steady rest on the machine tool, support the middle part of the long shaft with the steady rest, rotate the long shaft, measure the end runout of the long shaft, install a center drill on the tailstock of the machine tool, drill the tailstock hole of the non-reference end or reference end of the long shaft that meets the minimum end runout requirement of the long shaft, replace the center drill with a first center, hold the first center against the tailstock hole of the non-reference end or reference end, move the steady rest away from the middle part, and rotate the long shaft, and mark the best reference position for installing the steady rest at the part with a large runout deviation in the middle of the long shaft.

[0018] Further, the allowance left for rough turning the outer diameter in S3 is 6 - 7 mm.

[0019] Further, the width of the reference plane of the steady rest in S4 is 18 - 25 mm.

[0020] Further, the reference calibration tooling in S4 includes a ring sleeve and four adjusting bolts evenly arranged and penetrating through the ring sleeve respectively. The ring sleeve can be installed in the chuck jaws of the machine tool. The four adjusting bolts are threadedly connected to the ring sleeve, and the inner ends of the four adjusting bolts are used to adjust the position of the long shaft.

[0021] Furthermore, the technical parameter specification requirements for the long screw rod in S5 are as follows: the outer diameter runout ≤ 2 mm, the straightness ≤ 2 mm. The performance of the long screw rod is tested in S5: in an environment of 0 °C, the steel bar impact test reaches ≥ 90 KV2 (J), the specified plastic extension strength Rp0.2 ≥ 850 Mpa, the tensile strength Rm ≥ 950 Mpa, and the elongation after fracture A ≥ 15%.

[0022] The beneficial effects of the present invention: The processing flow of the steel long screw rod of the present invention is as follows: quenching and straightening process → supplementary tempering process → datum setting process → turning center rest datum process → long screw rod processing process, which can effectively improve the mechanical properties and straightness of the steel bar, and at the same time solve the problems of easy chatter and collision during processing, improve the processing efficiency, and at the same time enable the dimensions to meet the technical parameter requirements of the outer diameter runout ≤ 2 mm and the straightness ≤ 2 mm;

[0023] The quenching and straightening process can heat-treat the steel bar raw material. The warped steel bar after heat treatment is hot-straightened at a specified temperature so that the straightness of the steel bar is straightened to 1 - 2 mm, and then air-cooled after straightening to ensure the straightness of the steel bar, solve the problem of serious warping of the long screw rod, and meet the requirements of machining, and at the same time enable it to meet the assembly requirements;

[0024] In the supplementary tempering process, through secondary tempering, not only can the comprehensive mechanical properties of the steel bar be improved, but also the problem that the steel bar cannot reach the 54 J standard in an environment of 0 °C after heat treatment can be solved. At the same time, it can also solve the problems of insufficient strength of the existing bar stock, which is prone to local bending, elastic failure, and abnormal assembly of the electrolytic cell. It can prevent the hidden danger that the steel bar will break and the electrolytic cell will be severely damaged in the extreme working environment after heat treatment of the steel bar, and at the same time prevent the phenomenon of the electrolytic cell bouncing apart. The datum setting process uses the method of measuring the end jump of the long axis end to screen out qualified long axes, drills center punch holes at the datum end and non-datum end of the long axis, and at the same time marks the best datum position for the placement of the center rest measured twice to improve the accuracy of the center rest datum plane and avoid the problem of frequent tool collision caused by serious deviation of the center punch hole position;

[0025] The turning center rest datum process uses a datum calibration tooling to adjust the relative position between the long axis and the second center punch, and marks and turns out the center rest datum plane in the double-center punch state of the first center punch and the second center punch to balance the deviation on both sides of the center rest datum plane in the middle of the long axis, reduce the difference in cutting allowance at both ends, and solve the problem of easy chatter during processing;

[0026] The processing technology of the long screw adopts a steady rest to hold the reference surface of the steady rest, and balances the deviation on both sides of the reference surface of the steady rest in the middle of the long axis, so that the machining allowance can be evenly distributed during rough turning, so that the outer diameter can be fully machined during subsequent semi-finish turning and finish turning of the outer diameter, so as to avoid the problem of non-circular outer diameter caused by the inability to machine the outer diameter. At the same time, the allowance can also be machined step by step to reduce the problem of chatter. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is the front view of the machine tool for the processing method of the steel long screw for the electrolytic cell of a hydrogen production equipment of the present invention;

[0029] Figure 2 is for the processing method of the steel long screw for the electrolytic cell of a hydrogen production equipment of the present invention Figure 1 the enlarged view of A in;

[0030] Figure 3 is the cross-sectional view of the reference calibration tooling for the processing method of the steel long screw for the electrolytic cell of a hydrogen production equipment of the present invention;

[0031] Figure 4 is the schematic diagram of the ideal state and the actual state of the long axis for the processing method of the steel long screw for the electrolytic cell of a hydrogen production equipment of the present invention;

[0032] In the figure: 1 - machine tool, 2 - steady rest, 3 - reference calibration tooling, 4 - long axis, 5 - tailstock, 11 - chuck, 12 - jaw, 13 - first center punch, 14 - second center punch, 41 - reference surface of the steady rest, 31 - collar, 32 - adjusting bolt. Detailed Embodiments

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] In a specific embodiment of the present invention, as Figures 1 - 4 shown, a processing method of a steel long screw for an electrolytic cell of a hydrogen production equipment is specifically disclosed, and the specific steps of the method are as follows:

[0035] Tempering and straightening process: The steel bar raw material must comply with the fastener alloy steel of EU Directive 2014 / 68 / EU. The steel bar raw material is placed in a heated furnace for tempering treatment. The tempering treatment method is as follows: Quenching treatment: Heat the furnace to 920±50℃ to heat the steel bar raw material, the heating rate is 50℃~200℃ / h, and then keep it warm for 1-4 hours. After keeping warm, cool it with oil, the oil temperature is controlled at 20~50℃, and the cooling rate is 50℃~200℃ / h;

[0036] High temperature tempering treatment: heat the temperature to 600±50℃, keep it warm for 2-8 hours, and then air cool it to 250℃±20℃;

[0037] After high-temperature tempering and heat preservation, cool to the specified temperature, check the straightness, and if the measured straightness is greater than 4mm, the steel bar is in a warped state. Use a temperature measuring tool to measure the warped steel bar. When the temperature reaches the straightening temperature, use the straightening equipment for heat calibration to calibrate the straightness of the warped steel bar to 1-2mm. After the straightening is completed, air cool;

[0038] After high-temperature tempering and heat preservation, it is cooled to 250℃±20℃, and the straightness is checked by visual inspection. The measured straightness is>4mm, and the steel bar is in a warped state. A temperature measuring tool is used to measure the warped steel bar. In this embodiment, the temperature measuring tool is a temperature measuring gun. In other embodiments, it can be other measuring tools. When the temperature reaches 250℃±20℃, a straightening device is used for heat calibration to calibrate the straightness of the warped steel bar to 1-2mm, and air cool after straightening.

[0039] Supplementary tempering process: air-cool the straightened steel bars to room temperature, which is 0-30°C, and put the bars into the furnace for secondary tempering treatment, with the secondary tempering temperature being 400±150°C, to improve the comprehensive mechanical properties, which include the strength, hardness and toughness of the steel bars, so that the steel bars meet the EU CE standards and usage requirements;

[0040] Reference setting process: a steel rod is used as the long axis 4 of the long screw, and one end of the long axis 4 is randomly selected as the reference end and the other end is used as the non-reference end. The reference end of the long axis 4 is clamped by the chuck 11 of the machine tool 1. The reference end of the long axis 4 is clamped by the chuck 11 of the machine tool 1. A center frame 2 is installed on the machine tool 1. The middle part of the long axis 4 is supported by the center frame 2. The long axis 4 is rotated, and the end runout of the long axis 4 is measured. A center drill is installed on the ejector seat 5 of the machine tool 1. For the long axis 4 that meets the minimum end runout requirement of the long axis 4, an ejector hole at the non-reference end is drilled. The center drill is replaced with a first ejector 13. The first ejector 13 is supported by the ejector hole at the non-reference end. The center frame 2 is moved away from the middle part, and the long axis 4 is rotated. The best reference position for setting up the center frame 2 is marked at the part with large runout deviation in the middle part of the long axis 4.

[0041] Turn the long shaft 4 around and clamp the non-reference end with the chuck 11 of the machine tool 1. Install the steady rest 2 on the machine tool 1. Use the steady rest 2 to support the middle part of the long shaft 4. Clamp the non-reference end of the long shaft 4 with the chuck 11 of the machine tool 1. Install the steady rest 2 on the machine tool 1. Use the steady rest 2 to support the middle part of the long shaft 4. Rotate the long shaft 4 and measure the end run of the long shaft 4. Install a center drill on the tailstock 5 of the machine tool 1 and drill the center hole at the reference end of the long shaft 4 that meets the minimum end run requirement of the long shaft 4. Replace the center drill with the first center punch 13. Press the first center punch 13 against the center hole at the reference end. Move the steady rest 2 away from the middle part and rotate the long shaft 4. Mark the best reference position for installing the steady rest 2 at the part with a large runout deviation in the middle of the long shaft 4;

[0042] Steady rest reference process: Change the clamping method, reverse the direction of the long shaft 4. Install the first center punch 13 on the tailstock 5 of the machine tool 1. Clamp the reference calibration tooling 3 in the jaws 12 of the chuck 11 of the machine tool 1. Clamp the second center punch 14 in the jaws of the chuck 11 and it is located inside the tooling. Adjust the reference calibration tooling 3 to move the position of the long shaft 4 so that both the first center punch 13 and the second center punch 14 press against the center holes at both ends of the long shaft 4. Rotate in the double-center state and perform external turning on the best reference position of the marked steady rest 2 to turn out the outer diameter of the long shaft 4. This position serves as the steady rest reference surface 41. In this embodiment, the width of the turned-out steady rest reference surface 41 is 20 mm;

[0043] Long screw processing process: Move the steady rest 2 to the steady rest reference surface 41, support the long shaft 4, and perform rough turning on the outer diameter of the long shaft 4. The allowance left after rough turning the outer diameter is 6 - 7 mm; semi-finish turning the outer diameter, turning the non-reference end face, finish turning the outer diameter and machining the threads at both ends of the long shaft 4, and polish the outer diameter to complete the processing of the long screw so that the technical parameters of the long screw are within the specified requirements. The specified requirements for the technical parameters of the long screw: outer diameter runout ≤ 2 mm, straightness ≤ 2 mm, and test the performance of the long screw. Test the performance of the long screw: In an environment of 0 °C, the steel bar impact test reaches ≥ 90 KV2 (J), the specified plastic extension strength Rp0.2 ≥ 850 Mpa, the tensile strength Rm ≥ 950 Mpa, and the elongation after fracture A ≥ 15%.

[0044] The reference calibration tooling 3 includes a collar 31 and four adjusting bolts 32 evenly arranged and penetrating through the collar 31. The collar 31 can be installed in the jaws 12 of the chuck 11 of the machine tool 1. The four adjusting bolts 32 are threadedly connected to the collar 31, and the inner ends of the four adjusting bolts are used to adjust the position of the long shaft 4.

[0045] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for processing a steel long screw for an electrolyzer of hydrogen production equipment, characterized in that: The specific steps of the method are as follows: S1. The steel bar raw material is subjected to conditioning treatment. After the treatment, the straightness is checked. If the straightness is measured to be greater than 4mm, the steel bar is in a warped state. The warped steel bar is measured using a temperature measuring tool. When the temperature reaches the straightening temperature, a heat calibration is performed to calibrate the straightness of the warped steel bar to 1-2mm. S2. After straightening, the steel bar is air-cooled to room temperature and subjected to secondary tempering treatment; S3. Use a steel rod as the long axis of the long screw, one end of the long axis as the reference end, and the other end as the non-reference end. The machine tool chuck clamps the reference end of the long axis, and uses the reference method to drill a pinhole on the non-reference end of the long axis, and at the same time mark the best reference position for setting up the center frame; Turn the long shaft around and clamp the non-reference end, install a center frame on the machine tool, use the center frame to support the middle of the long shaft, use the reference method to drill the ejector hole at the reference end of the long shaft, and mark the best reference position for setting up the center frame at the same time; S4, change the clamping mode, change the direction of the long axis, clamp a reference calibration tool in the jaws of the machine tool chuck, move the long axis position by adjusting the reference calibration tool, and rotate in the double-top state of the first ejector and the second ejector, and perform external turning on the best reference position of the marked center frame to turn out the outer circle of the long axis, and this position is used as the reference surface of the center frame; S5. Move the center frame to the center frame reference plane, hold the long axis, and perform rough turning of the outer diameter, semi-finishing of the outer diameter, turning of the non-reference end face, finishing of the outer diameter, and processing of the threads at both ends of the long axis to complete the processing of the long screw.

2. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The steel bar material in S1 is fastener alloy steel that complies with EU Directive 2014 / 68 / EU.

3. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The modulation treatment method in S1 includes quenching treatment and high-temperature tempering treatment. Quenching treatment: heating the furnace to 920±50℃ to heat the steel bar raw material, the heating rate is 50℃~200℃ / h, and then keeping it warm for 1-4 hours. After keeping warm, cooling with oil, the oil temperature of the oil cooling is controlled at 20~50℃, and the cooling rate is 50℃~200℃ / h; high-temperature tempering treatment: heating the temperature to 600±50℃, keeping warm for 2-8 hours, air cooling to a temperature of 250℃±20℃ after keeping warm, cooling to a specified temperature after high-temperature tempering and keeping warm, and the specified temperature is 250℃±20℃.

4. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The temperature measuring tool in S1 is a temperature measuring gun, and the straightening temperature in S1 is 250°C±20°C.

5. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The room temperature in S2 is 0-30°C, and the secondary tempering temperature is 400±150°C. After the secondary tempering treatment, the comprehensive mechanical properties of the steel bar are improved, and the comprehensive mechanical properties include the strength, hardness and toughness of the steel bar. At the same time, the steel bar meets the EU CE standards and usage requirements.

6. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The method for determining the reference in S3 is as follows: use a machine tool chuck to clamp the reference end or non-reference end of the long axis, install a center frame on the machine tool, use the center frame to support the middle of the long axis, rotate the long axis, measure the end runout of the long axis, install a center drill on the thimble seat of the machine tool, drill the thimble hole at the non-reference end or the reference end of the long axis that meets the minimum end runout requirement of the long axis, replace the center drill with a first thimble, support the thimble hole at the non-reference end or the reference end with the first thimble, move the center frame away from the middle, rotate the long axis, and mark the best reference position for setting up the center frame at the location in the middle of the long axis where the runout deviation is larger.

7. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The allowance for the outer diameter in the rough turning of S3 is 6-7mm.

8. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The first ejector and the second ejector in S4 are installed in the following manner: the first ejector is installed on the ejector seat of the machine tool, a reference calibration tool is clamped in the chuck jaws of the machine tool, and the second ejector is clamped in the chuck jaws and is located on the inner side of the tool; The width of the center frame reference surface in S4 is 18-25mm.

9. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The reference calibration tool in S4 includes a ring sleeve and four adjustment bolts evenly distributed on the ring sleeve. The ring sleeve can be installed in the chuck jaws of the machine tool. The four adjustment bolts are threadedly connected to the ring sleeve, and the inner ends of the four adjustment bolts are used to adjust the position of the long axis.

10. The method for processing a steel long screw for an electrolyzer of hydrogen production equipment according to claim 1, characterized in that: The technical parameter requirements met by the long screw in S5 are: outer diameter runout ≤ 2mm, straightness ≤ 2mm. The performance of the long screw in S5 is: under 0°C environment, the steel bar impact test reaches ≥90KV2 (J), the specified plastic extension strength Rp0.2 ≥850Mpa, the tensile strength Rm ≥950Mpa, and the elongation after fracture A ≥15%.

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