Hydraulic oil cylinder body for pile driving barge pile frame and manufacturing method of hydraulic oil cylinder body

Abstract

The invention relates to the technical field of hydraulic equipment, and discloses a hydraulic oil cylinder body for a pile driving barge pile frame and a manufacturing method of the hydraulic oil cylinder body, and the hydraulic oil cylinder body is mainly prepared from carbon C, copper Cu, silicon Si, magnesium Mg, chromium Cr, manganese Mn, nickel Ni, molybdenum Mo, rhenium RE and the balance metal through smelting casting forming. According to the material formula, through accurate alloy element proportion design, comprehensive optimization of material performance is achieved, the carbon content is controlled within the range of 3.000-3.800%, and through reasonable addition of elements such as copper, silicon and magnesium, the material has the excellent characteristics of high strength and high toughness at the same time; through the synergistic effect of alloy elements such as chromium, manganese, nickel and molybdenum, the hardenability, wear resistance and corrosion resistance of the material are remarkably improved, particularly, the grain structure is effectively refined through addition of trace rhenium, and the anti-fatigue performance of the material is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic equipment technology, specifically to a hydraulic cylinder body for a pile driver on a piling vessel and its manufacturing method. Background Technology

[0002] Piling equipment is widely used in the construction industry. Its main function is to insert steel columns deep into the soil to provide solid and reliable support for the superstructure. The steel columns are usually driven vertically into the soil by a piling vessel. Conventional piling vessels mostly use a single hydraulic cylinder to lift and lower the pile frame. As piling vessels continue to develop towards larger sizes, the self-weight of the pile frame and the lifting load are also increasing. The single hydraulic cylinder lifting system for the pile frame has increasingly higher requirements for the capacity of the hydraulic cylinder, and the manufacturing difficulty and procurement cost of the hydraulic cylinder have also increased significantly.

[0003] With the development of marine engineering and large-scale infrastructure construction, piling vessels, as key equipment for offshore pile foundation construction, are facing increasingly complex operating environments. Traditional piling vessel hydraulic cylinders for pile frames present the following problems:

[0004] The presence of a high-salt-spray corrosion environment, coupled with the penetration of chloride ions in the marine environment, can easily lead to pitting corrosion on the inner wall of the cylinder. The existing chromium plating on the carbon steel will peel off after long-term operation. Summary of the Invention

[0005] The purpose of this invention is to provide a hydraulic cylinder body for a piling vessel pile frame and a method for manufacturing the same, in order to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: providing a hydraulic cylinder body for a piling ship pile frame and a method for manufacturing the same.

[0007] In a first aspect, the present invention provides a technical solution: a hydraulic cylinder body for a piling frame on a piling vessel, the cylinder body being mainly formed by melting and casting carbon (C), copper (Cu), silicon (Si), magnesium (Mg), chromium (Cr), manganese (Mn), nickel (Ni), molybdenum (Mo), rhenium (RE), and the balance metals, wherein the cylinder body materials are as follows by weight percentage:

[0008] Carbon (C): 3.000-3.800%;

[0009] Copper (Cu): 0.800-1.500%;

[0010] Silicon (Si): 2.000-2.800%;

[0011] Magnesium (Mg): 0.030-0.060%;

[0012] Chromium (Cr): 0.400-0.800%;

[0013] Manganese (Mn): 0.500-1.200%;

[0014] Nickel Ni: 0.200-0.500%;

[0015] Molybdenum: 0.300-0.600%;

[0016] Rhenium RE: 0.010-0.030%;

[0017] The remaining metal consists of iron (Fe) and unavoidable impurities.

[0018] Furthermore, the preferred range for the weight percentage composition of the cylinder block material is as follows:

[0019] Carbon (C): 3.200-3.500%;

[0020] Copper (Cu): 1.000-1.200%;

[0021] Silicon (Si): 2.200-2.800%;

[0022] Magnesium (Mg): 0.040-0.050%;

[0023] Chromium (Cr): 0.500-0.600%;

[0024] Manganese (Mn): 0.700-0.900%;

[0025] Nickel Ni: 0.300-0.400%;

[0026] Molybdenum: 0.400-0.500%;

[0027] Rhenium RE: 0.015-0.020%.

[0028] Furthermore, the inner wall of the cylinder has a gradient hardening layer with a surface hardness ≥ HRC55, a hardening layer depth of 1.5-2mm, and a core hardness of HRC28-32. The end of the cylinder is provided with an integrated fluororubber sealing groove with a sealing groove depth of 3±0.1mm and a groove wall inclination angle of 15°±1°.

[0029] Secondly, based on the hydraulic cylinder body material for the pile frame of the piling vessel provided in the first aspect, this solution also provides a method for manufacturing the cylinder body.

[0030] A method for manufacturing a hydraulic cylinder body for a piling frame on a piling vessel includes the following steps:

[0031] S1, smelting and pelletizing;

[0032] S2, casting;

[0033] S3, heat treatment;

[0034] S4, Surface strengthening.

[0035] Furthermore, the smelting and spheroidizing process described in step S1 is as follows:

[0036] a. Melt the raw materials in a medium-frequency induction furnace at 1520-1550℃;

[0037] b. Spheroidization treatment using the bottom pouring method: Place a magnesium-rhenium RE alloy containing 40wt% magnesium (Mg) at the bottom of the ladle, cover it with ferrosilicon inoculant, and then pour in molten iron at ≥1480℃.

[0038] Furthermore, the casting process described in step S2 is as follows:

[0039] a. Use coated sand resin molds, with a pouring temperature of 1380-1400℃;

[0040] b. Install chills at the thickest part of the cylinder wall, with the chill thickness being 1.5 times the cylinder wall thickness.

[0041] Furthermore, the heat treatment process described in step S3 involves annealing, quenching, and finally tempering to complete the heat treatment process, including the following steps:

[0042] a. Annealing, hold at 920℃ for 2 hours → furnace cooling to 740℃ and hold for 4 hours → furnace cooling to 500℃ and remove from the furnace;

[0043] b. Quenching: Salt bath heating at 880℃ for 45 minutes → rapid oil quenching at 80℃, with a cooling rate of 80-100℃ / s;

[0044] c. Tempering: Hold at 550℃ for 3 hours and air cool → Hold at 200℃ for 2 hours to relieve stress.

[0045] Furthermore, the surface strengthening process described in step S4 involves plasma nitriding of the inner wall of the cylinder: heat treatment at 520℃ for 24 hours, nitriding layer depth ≥0.3mm, nitrogen partial pressure of 300-500Pa, and hydrogen flow ratio of 1:3.

[0046] Thirdly, based on the cylinder material provided in the first aspect and the cylinder manufacturing method provided in the second aspect, this solution also provides a hydraulic cylinder, a hydraulic cylinder for a pile frame of a piling vessel, which is composed of a cylinder barrel mechanism, a piston mechanism, a sealing mechanism, a cylinder seat, and a rod head that are tightly fitted together.

[0047] The piston mechanism also includes a piston rod, and a piston is tightly fitted onto the outer wall of the front end of the piston rod. A buffer sleeve is fitted onto the outer wall of the piston rod and close to the piston. An anti-wear ring is provided at one end of the buffer sleeve and fitted onto the outer wall of the piston rod.

[0048] The sealing mechanism also includes a cylinder cover and a sealing flange.

[0049] Furthermore, the outer wall of the piston mechanism is tightly fitted and penetrates the sealing mechanism, which is inserted into the inner wall of the cylinder mechanism.

[0050] The present invention has the following beneficial effects:

[0051] (1) The material formulation of this invention achieves comprehensive optimization of material properties through precise alloy element ratio design. The carbon content is controlled within the range of 3.000-3.800%, and with the reasonable addition of elements such as copper, silicon, and magnesium, the material possesses excellent properties of both high strength and high toughness. The synergistic effect of alloying elements such as chromium, manganese, nickel, and molybdenum significantly improves the hardenability, wear resistance, and corrosion resistance of the material. In particular, the addition of trace amounts of rhenium effectively refines the grain structure and greatly improves the fatigue resistance of the material.

[0052] (2) The material of this invention adopts an innovative gradient hardness design concept. The surface hardness of the inner wall ≥ HRC55 ensures excellent wear resistance, while the core hardness is controlled at HRC28-32 to provide sufficient toughness reserve. This gradient hardness distribution allows the cylinder to withstand high-frequency friction and wear while effectively resisting impact loads, avoiding the risk of brittle fracture. The precision design of the integrated fluororubber sealing groove (depth 3±0.1mm, inclination angle 15°±1°) significantly improves sealing reliability by optimizing the sealing contact pressure distribution, reducing hydraulic oil leakage rate by more than 90%.

[0053] (3) The material formulation of this invention also pays special attention to improving casting process performance. Through precise control of silicon content (2.000-2.800%) and the composite addition of magnesium-rare earth elements, the fluidity of molten iron is increased by 30%, and the graphite spheroidization rate reaches over 90%. This not only significantly reduces casting defects such as shrinkage cavities and porosity, but also increases the casting yield to over 98%. The optimized composition design enables the material to exhibit excellent corrosion resistance in marine corrosive environments, reducing the salt spray corrosion rate by 60%, fully meeting the long-term use requirements of marine engineering equipment such as piling vessels.

[0054] (4) This invention employs an innovative smelting process, using a medium-frequency induction furnace at 1520-1550℃ with argon protection to strictly control the gas content ([H]≤2ppm, [O]≤20ppm) and inclusion size (≤20μm) of the molten iron. A magnesium-rhenium alloy containing 40wt% magnesium is used for bottom-punching spheroidization treatment, combined with the use of ferrosilicon inoculants, resulting in a stable graphite spheroidization rate of 90-95%, significantly better than the 80-85% of traditional processes, providing high-quality billets for subsequent processing.

[0055] (5) In the casting process of this invention, a coated resin sand mold is used, combined with precise pouring temperature control of 1380-1400℃, so that the surface roughness of the casting reaches Ra≤6.3μm and the dimensional accuracy is controlled at CT7 level. The innovative chill system design (the chill thickness is 1.5 times the cylinder wall thickness) increases the cooling rate of thick parts by 50%, completely eliminating shrinkage defects. The heat treatment process adopts an annealing process of holding at 920℃ for 2 hours followed by stepped cooling, so that the residual stress elimination rate reaches more than 95%. Salt bath quenching at 880℃ combined with rapid oil quenching at 80-100℃ / s obtains a uniform structure with a martensite content ≥90%. The final tempering treatment perfectly balances hardness and toughness.

[0056] (6) The surface strengthening process of this invention employs a plasma nitriding process with a heat treatment temperature of 520℃ for 24 hours. By precisely controlling the nitrogen partial pressure (300-500 Pa) and the hydrogen flow ratio (1:3), a compound layer with a thickness of 10-15 μm and a diffusion layer with a depth of ≥0.3 mm are formed. This process ensures a smooth transition in surface hardness gradient, avoids the formation of brittle phases, and improves wear resistance by more than 5 times. The entire manufacturing process achieves precise control at each stage, with product performance consistency reaching 99% and a scrap rate controlled below 0.5%, providing a reliable guarantee for the mass production of high-quality hydraulic cylinder bodies.

[0057] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0058] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the cylinder block structure of the present invention;

[0060] Figure 2 For the present invention Figure 1 A schematic diagram of the exploded structure;

[0061] The attached diagram lists the components represented by each number as follows:

[0062] In the diagram: 1. Cylinder mechanism; 2. Piston mechanism; 21. Piston rod; 22. Piston; 23. Buffer sleeve; 24. Anti-wear ring; 3. Sealing mechanism; 31. Cylinder cover; 32. Sealing flange; 4. Cylinder seat; 5. Rod head. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] In a first aspect, the present invention provides a technical solution: a hydraulic cylinder body for a piling frame on a piling vessel, the cylinder body being mainly formed by melting and casting carbon (C), copper (Cu), silicon (Si), magnesium (Mg), chromium (Cr), manganese (Mn), nickel (Ni), molybdenum (Mo), rhenium (RE), and the balance metals, with the cylinder body materials as follows by weight percentage:

[0065] Carbon (C): 3.000-3.800%;

[0066] Copper (Cu): 0.800-1.500%;

[0067] Silicon (Si): 2.000-2.800%;

[0068] Magnesium (Mg): 0.030-0.060%;

[0069] Chromium (Cr): 0.400-0.800%;

[0070] Manganese (Mn): 0.500-1.200%;

[0071] Nickel Ni: 0.200-0.500%;

[0072] Molybdenum: 0.300-0.600%;

[0073] Rhenium RE: 0.010-0.030%;

[0074] The remaining metal consists of iron (Fe) and unavoidable impurities.

[0075] Preferably, the preferred range for the weight percentage composition of the cylinder block material is:

[0076] Carbon (C): 3.200-3.500%;

[0077] Copper (Cu): 1.000-1.200%;

[0078] Silicon (Si): 2.200-2.800%;

[0079] Magnesium (Mg): 0.040-0.050%;

[0080] Chromium (Cr): 0.500-0.600%;

[0081] Manganese (Mn): 0.700-0.900%;

[0082] Nickel Ni: 0.300-0.400%;

[0083] Molybdenum: 0.400-0.500%;

[0084] Rhenium RE: 0.015-0.020%.

[0085] The cylinder body has a gradient hardening layer with a surface hardness ≥ HRC55 and a hardening layer depth of 1.5-2 mm. The core hardness is HRC28-32. The cylinder body end is equipped with an integrated fluororubber sealing groove with a groove depth of 3±0.1 mm and a groove wall inclination angle of 15°±1°.

[0086] In this embodiment, the cylinder block material formulation achieves comprehensive optimization of material performance through precise alloy element ratio design. The carbon content is controlled within the range of 3.000-3.800%, and with the reasonable addition of elements such as copper, silicon, and magnesium, the material possesses excellent characteristics of both high strength and high toughness. The synergistic effect of alloying elements such as chromium, manganese, nickel, and molybdenum significantly improves the material's hardenability, wear resistance, and corrosion resistance. In particular, the addition of trace amounts of rhenium effectively refines the grain structure and greatly improves the material's fatigue resistance.

[0087] The material employs an innovative gradient hardness design concept. The inner wall surface hardness ≥ HRC55 ensures excellent wear resistance, while the core hardness controlled at HRC28-32 provides sufficient toughness reserves. This gradient hardness distribution allows the cylinder block to withstand high-frequency friction and wear while effectively resisting impact loads, avoiding the risk of brittle fracture. The precise design of the integrated fluororubber sealing groove (depth 3±0.1mm, inclination angle 15°±1°) significantly improves sealing reliability by optimizing the sealing contact pressure distribution, reducing hydraulic oil leakage rate by more than 90%.

[0088] Furthermore, the cylinder block material formulation places special emphasis on improving casting process performance. Through precise control of silicon content (2.000-2.800%) and the composite addition of magnesium and rare earth elements, the fluidity of molten iron is increased by 30%, and the graphite spheroidization rate reaches over 90%. This not only significantly reduces casting defects such as shrinkage cavities and porosity but also increases the casting yield to over 98%. The optimized composition design enables the material to exhibit excellent corrosion resistance in marine corrosive environments, reducing the salt spray corrosion rate by 60%, fully meeting the long-term use requirements of marine engineering equipment such as piling vessels.

[0089] Secondly, based on the first aspect, the present invention provides a technical solution: a method for manufacturing a hydraulic cylinder body for a piling vessel pile frame, the method comprising the following steps:

[0090] S1, smelting and pelletizing;

[0091] a. Melt the raw materials in a medium-frequency induction furnace at 1520-1550℃;

[0092] b. Spheroidization treatment using the bottom pouring method: Place a magnesium-rhenium RE alloy containing 40wt% magnesium (Mg) at the bottom of the ladle, cover it with ferrosilicon inoculant, and then pour in molten iron at ≥1480℃.

[0093] S2, casting;

[0094] a. Use coated sand resin molds, with a pouring temperature of 1380-1400℃;

[0095] b. Install chills at the thickest part of the cylinder wall, with the chill thickness being 1.5 times the cylinder wall thickness.

[0096] S3. Heat treatment: first annealing, then quenching, and finally tempering to complete the heat treatment process, including the following steps:

[0097] a. Annealing, hold at 920℃ for 2 hours → furnace cooling to 740℃ and hold for 4 hours → furnace cooling to 500℃ and remove from the furnace;

[0098] b. Quenching: Salt bath heating at 880℃ for 45 minutes → rapid oil quenching at 80℃, with a cooling rate of 80-100℃ / s;

[0099] c. Tempering: Hold at 550℃ for 3 hours and air cool → Hold at 200℃ for 2 hours to relieve stress;

[0100] S4. Surface strengthening: Plasma nitriding treatment is performed on the inner wall of the cylinder: heat treatment at 520℃ for 24 hours, nitriding layer depth ≥0.3mm, nitrogen partial pressure is 300-500Pa, and hydrogen flow ratio is 1:3.

[0101] In this embodiment, the hydraulic cylinder body manufacturing method optimizes each process step to ensure a high degree of consistency in product performance. By using a medium-frequency induction furnace for high-temperature melting at 1520-1550℃ combined with magnesium-rhenium alloy spheroidization treatment, the purity and spheroidization rate of the molten iron are significantly improved. The coated sand resin mold, combined with precisely controlled pouring temperature (1380-1400℃) and a reasonably set chiller system, effectively controls the solidification process of the casting and reduces casting defects.

[0102] The heat treatment process adopts a scientific process of annealing, quenching and tempering. The annealing process, which involves holding at 920℃ for 2 hours and then cooling in stages, effectively eliminates casting stress. Salt bath quenching at 880℃ combined with rapid oil quenching at 80-100℃ / s yields an ideal metallographic structure. The final tempering treatment perfectly balances hardness and toughness.

[0103] Furthermore, surface strengthening employs a plasma nitriding process with a heat treatment temperature of 520℃ for 24 hours. Under strict control of nitrogen partial pressure and hydrogen ratio, a high-quality nitrided layer with a depth ≥0.3mm is formed. This cylinder block manufacturing method not only ensures the stability of cylinder block performance but also improves production efficiency and reduces scrap rate, providing a reliable guarantee for the mass production of high-quality hydraulic cylinder blocks.

[0104] Thirdly, based on the first and second aspects, the present invention also provides a technical solution: a hydraulic cylinder for a pile frame of a piling vessel, the cylinder being composed of a cylinder mechanism 1, a piston mechanism 2, a sealing mechanism 3, a cylinder seat 4, and a rod head 5 that are tightly fitted together.

[0105] The piston mechanism 2 also includes a piston rod 21, and a piston 22 is tightly fitted onto the outer wall of the front end of the piston rod 21. A buffer sleeve 23 is fitted onto the outer wall of the piston rod 21 and close to the piston 22. An anti-wear ring 24 is provided at one end of the buffer sleeve 23 and fitted onto the outer wall of the piston rod 21.

[0106] The sealing mechanism 3 also includes a cylinder cover 31 and a sealing flange 32.

[0107] The outer wall of the piston mechanism 2 is tightly fitted and penetrates the sealing mechanism 3, which is inserted into the inner wall of the cylinder mechanism 1.

[0108] In this embodiment, the precise matching design of components such as cylinder mechanism 1, piston mechanism 2, sealing mechanism 3, cylinder seat 4, and rod head 5 ensures the overall reliability of the system. The piston mechanism 2 adopts a combination design of buffer sleeve 23 and anti-wear ring 24, which effectively alleviates the impact load and reduces the wear rate.

[0109] Among them, the sealing mechanism 3, through the dual sealing design of the cylinder cover 31 and the sealing flange 32, combined with the optimized fluororubber sealing groove structure, greatly improves the sealing performance and service life. The modular structural design makes the disassembly and maintenance of each component more convenient, significantly reducing maintenance costs and time.

[0110] In addition, the entire cylinder structure fully considers the special working conditions of piling vessel operations, and has been specifically optimized in terms of impact resistance, sealing reliability and maintenance convenience, so that it can adapt to harsh working conditions such as high frequency impact and high pressure load, while extending its service life and reducing the total life cycle cost.

[0111] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A hydraulic cylinder body for a piling frame on a piling vessel, the cylinder body being mainly formed by melting and casting carbon (C), copper (Cu), silicon (Si), magnesium (Mg), chromium (Cr), manganese (Mn), nickel (Ni), molybdenum (Mo), rhenium (RE), and other remaining metals, characterized in that... The cylinder block material is described by weight percentage as follows: Carbon (C): 3.000-3.800%; Copper (Cu): 0.800-1.500%; Silicon (Si): 2.000-2.800%; Magnesium (Mg): 0.030-0.060%; Chromium (Cr): 0.400-0.800%; Manganese (Mn): 0.500-1.200%; Nickel Ni: 0.200-0.500%; Molybdenum: 0.300-0.600%; Rhenium RE: 0.010-0.030%; The remaining metal consists of iron (Fe) and unavoidable impurities.

2. The hydraulic cylinder body for a piling frame on a piling vessel according to claim 1, characterized in that, The preferred range for the weight percentage composition of the cylinder block material is as follows: Carbon (C): 3.200-3.500%; Copper (Cu): 1.000-1.200%; Silicon (Si): 2.200-2.800%; Magnesium (Mg): 0.040-0.050%; Chromium (Cr): 0.500-0.600%; Manganese (Mn): 0.700-0.900%; Nickel Ni: 0.300-0.400%; Molybdenum: 0.400-0.500%; Rhenium RE: 0.015-0.020%.

3. The hydraulic cylinder body for a piling frame on a piling vessel according to claim 1, characterized in that, The inner wall of the cylinder has a gradient hardening layer with a surface hardness ≥ HRC55 and a hardening layer depth of 1.5-2mm. The core hardness is HRC28-32. The end of the cylinder is provided with an integrated fluororubber sealing groove with a sealing groove depth of 3±0.1mm and a groove wall inclination angle of 15°±1°.

4. A method for manufacturing the cylinder body of a hydraulic cylinder for a piling vessel, characterized in that, The manufacturing method of this cylinder block includes the following steps: S1, smelting and pelletizing; S2, casting; S3, heat treatment; S4, Surface strengthening.

5. A method for manufacturing a hydraulic cylinder body for a piling vessel pile frame according to claim 4, characterized in that, The smelting and spheroidizing processes described in step S1 are as follows: a. Melt the raw materials in a medium-frequency induction furnace at 1520-1550℃; b. Spheroidization treatment using the bottom pouring method: Place a magnesium-rhenium RE alloy containing 40wt% magnesium (Mg) at the bottom of the ladle, cover it with ferrosilicon inoculant, and then pour in molten iron at ≥1480℃.

6. A method for manufacturing a hydraulic cylinder body for a piling vessel pile frame according to claim 4, characterized in that, The casting process described in step S2 is as follows: a. Use coated sand resin molds, with a pouring temperature of 1380-1400℃; b. Install chills at the thickest part of the cylinder wall, with the chill thickness being 1.5 times the cylinder wall thickness.

7. A method for manufacturing a hydraulic cylinder body for a piling vessel pile frame according to claim 4, characterized in that, The heat treatment process described in step S3 involves annealing, quenching, and finally tempering to complete the heat treatment process, including the following steps: a. Annealing, hold at 920℃ for 2 hours → furnace cooling to 740℃ and hold for 4 hours → furnace cooling to 500℃ and remove from the furnace; b. Quenching: Salt bath heating at 880℃ for 45 minutes → rapid oil quenching at 80℃, with a cooling rate of 80-100℃ / s; c. Tempering: Hold at 550℃ for 3 hours and air cool → Hold at 200℃ for 2 hours to relieve stress.

8. A method for manufacturing a hydraulic cylinder body for a piling vessel pile frame according to claim 4, characterized in that, The surface strengthening process described in step S4 involves plasma nitriding of the inner wall of the cylinder: heat treatment at 520℃ for 24 hours, nitriding layer depth ≥0.3mm, nitrogen partial pressure of 300-500Pa, and hydrogen flow ratio of 1:

3.

9. A hydraulic cylinder for a piling frame on a piling vessel, the cylinder comprising a cylinder mechanism (1), a piston mechanism (2), a sealing mechanism (3), a cylinder seat (4), and a rod head (5) tightly fitted together, characterized in that, The piston mechanism (2) further includes a piston rod (21), and a piston (22) is tightly fitted on the outer wall of the front end of the piston rod (21). A buffer sleeve (23) is fitted on the outer wall of the piston rod (21) and close to the piston (22). An anti-wear ring (24) is provided on one end of the buffer sleeve (23) and fitted on the outer wall of the piston rod (21). The sealing mechanism (3) also includes a cylinder cover (31) and a sealing flange (32).

10. A hydraulic cylinder for a piling frame on a piling vessel according to claim 9, characterized in that, The outer wall of the piston mechanism (2) is tightly fitted and penetrates the sealing mechanism (3) inserted into the inner wall of the cylinder mechanism (1).

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