A precision carbon steel tube for hydraulic cylinders of construction machinery and a cold-drawing forming process thereof

Abstract

The present application relates to the technical field of steel pipe processing, in particular to a precision carbon steel pipe for engineering machinery hydraulic cylinder and a cold-drawing forming process thereof, comprising S1: raw material preparation: selecting high-quality hot-rolled seamless steel pipe as a blank; S2: pretreatment: annealing the blank to reduce hardness, straightening to ensure the straightness of the pipe body, and carrying out pipe head processing (such as necking and sharpening) to facilitate the clamping of the cold-drawing machine; S3: surface treatment and lubrication; S4: cold-drawing: on the cold-drawing device, the treated pipe blank is drawn and formed through a specially designed die. The precision carbon steel pipe for engineering machinery hydraulic cylinder and the cold-drawing forming process thereof have the advantages that by arranging symmetrical arc-shaped clamping pieces and utilizing the meshing transmission of the gear ring and the first gear rack, the clamping force is converted into the rotating force of the clamping pieces during the clamping process, additional rotating torque is applied to the steel pipe, and the clamping and positioning effect of the steel pipe is greatly enhanced, so that the steel pipe is stable and not easy to loosen during the cold-drawing process.

Description

Technical Field

[0001] This invention relates to the field of steel pipe processing technology, specifically to a precision carbon steel pipe for hydraulic cylinders of engineering machinery and its cold drawing forming process. Background Technology

[0002] In the cold drawing process of steel pipes, the cold drawing device is the core equipment for achieving precise pipe diameter reduction and wall thickness adjustment. Its working mechanism is to forcibly pull the pre-treated (such as pickling, phosphating, lubrication) tube blank through a hard alloy mold with a tapered inner hole, so that the tube undergoes plastic deformation under the action of external force. In this process, the clamping parts of the cold drawing device undertake the key task of stabilizing and pulling the end of the tube blank, ensuring that the pulling force is evenly transmitted to the axial direction of the tube.

[0003] Due to the intense plastic deformation of the steel pipe during cold drawing, and the high-speed friction between the outer surface of the steel pipe and the mold and clamping parts, a large amount of metal filings and abrasive particles are inevitably generated. These filings easily adhere to or become embedded in the clamping surface of the clamping parts. If the filings remaining on the surface of the clamping parts are not cleaned in time, when the clamping parts subsequently clamp the next steel pipe for cold drawing, the residual filings will be placed between the clamping parts and the outer wall of the steel pipe, resulting in uneven distribution of the actual contact surface between the clamping parts and the steel pipe, and localized stress concentration. The direct consequences include: firstly, the clamping parts... First, uneven force distribution can lead to eccentric stress on the steel pipe during cold drawing, resulting in dimensional inaccuracies such as uneven wall thickness and excessive ovality after drawing. Second, iron filings can be pressed into the surface of the steel pipe under high pressure, forming surface defects such as indentations, scratches, or pits, which seriously affect the surface quality and subsequent performance of the steel pipe. Third, long-term repeated clamping will aggravate the wear and deformation of the clamping components themselves, shorten the service life of the clamping components, and increase equipment maintenance costs. Fourth, in extreme cases, uneven contact surfaces may also lead to slippage during clamping, steel pipe falling off, causing equipment damage or even safety accidents. Summary of the Invention

[0004] The present invention aims to provide a precision carbon steel pipe for hydraulic cylinders of engineering machinery and its cold drawing forming process, in order to solve the problem that a large amount of iron filings adhere to or are embedded on the surface of the clamping part. If not cleaned in time, the iron filings will be separated between the clamping part and the steel pipe when clamping again, resulting in uneven distribution of contact surface and local stress concentration.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A precision carbon steel pipe for hydraulic cylinders in engineering machinery is disclosed. The pipe has an inner diameter of 4mm-219mm, a wall thickness of 0.5mm-25mm, an outer diameter tolerance of ±0.20mm, an inner diameter tolerance of ±0.20mm, and a wall thickness tolerance controlled within the following ranges: ±0.05mm when 0.5mm ≤ wall thickness < 1mm; ±0.1mm when 1mm ≤ wall thickness < 5mm; and ±0.5mm when 5mm ≤ wall thickness < 10mm. mm; when the wall thickness is 10mm≤wall thickness≤25mm, the tolerance is ±1.0mm. The surface roughness Ra of the precision carbon steel pipe is ≤1.6μm, the tensile strength is Rm≥390MPa, and the yield strength is ReH≥245MPa. The inner and outer walls of the precision carbon steel pipe are free of oxide layer, and there are no cracks when cold bending, flaring, or flattening. It can withstand 1.5 times the rated working pressure and maintain pressure without leakage. After the surface is rolled, a residual stress layer is formed, which increases the fatigue strength by about 30%.

[0007] Preferably, a cold drawing forming process for precision carbon steel tubes used in hydraulic cylinders of engineering machinery includes the following steps:

[0008] S1: Raw material preparation: High-quality hot-rolled seamless steel pipes are selected as billets;

[0009] S2: Pretreatment: Anneal the billet to reduce hardness, straighten it to ensure the tube is straight, and perform tube end processing (such as necking and tapering) to facilitate clamping by the cold drawing machine;

[0010] S3: Surface treatment and lubrication: including pickling: removing oxide scale and rust from the inner and outer surfaces of the pipe; neutralization and washing: removing residual acid; phosphating / saponification: forming a lubricating and load-bearing film on the surface of the steel pipe in preparation for cold drawing.

[0011] S4: Cold drawing: On a cold drawing device, the processed tube blank is drawn into shape through a specially designed die.

[0012] Preferably, a cold drawing device is used to cold draw and form precision carbon steel tubes for hydraulic cylinders of engineering machinery. The device includes a processing table with a shaping plate installed on the top of the processing table. A shaping hole is opened in the middle of the shaping plate, through which the steel tube can slide for cold drawing and shaping. A cold drawing mechanism is provided on the processing table, which includes a clamping component and a driving component. The driving component is used to drive the clamping component to clamp and position the steel tube for cold drawing.

[0013] Preferably, a clamping assembly is used to clamp and fix the steel pipe. The clamping assembly includes symmetrically arranged clamping members. A first connecting frame is installed on the outside of each clamping member. A first limiting shaft is fixed at the top and bottom of each clamping member. A first limiting hole adapted to the first limiting shaft is opened on the first connecting frame. The outer wall of the first limiting shaft is rotatably connected to the hole wall of the corresponding first limiting hole. A second connecting frame is installed on the opposite side of the two first connecting frames. A second limiting shaft is rotatably connected to the opposite side of the two first connecting frames. A second limiting hole adapted to the second limiting shaft is opened on one side of the second connecting frame. The second limiting shaft is coaxially arranged with the corresponding second limiting hole, and the outer wall of the second limiting shaft fits against the hole wall of the corresponding second limiting hole. A support plate is rotatably connected to the end of the second limiting shaft away from the first connecting frame. A first return spring is fixed between the support plate and the second connecting frame.

[0014] Preferably, a moving platform is used to move the clamping component to the steel pipe for clamping and positioning. A hinge is installed between the two second connecting frames. A moving platform is installed at the bottom of the hinge. The top of the moving platform is connected to the bottom of the hinge by a pin. A hydraulic cylinder is installed on one side of the moving platform. The piston rod end of the hydraulic cylinder is connected to one side of the hinge.

[0015] Preferably, the driving component drives the clamping component to clamp and position the clamped steel pipe. The driving component includes connecting frames symmetrically arranged outside the first connecting frame. Each first connecting frame has two corresponding connecting frames. A first rack is installed on the inner wall of the connecting frame. A toothed ring is fixed on the outer wall of one end of the first limiting shaft that extends out of the first limiting hole. The toothed ring is meshed with the first rack.

[0016] Preferably, the steel pipe is cold-drawn by using a drive gear and a second rack to drive the clamping device. A drive source is installed on the moving table, a drive gear is installed at the output end of the drive source, and a second rack is installed on the inner side of the processing table, with the drive gear and the second rack meshing together.

[0017] Preferably, a cleaning mechanism is used to clean the clamping surface of the clamping member. The clamping member is provided with a cleaning mechanism, which includes a cleaning component disposed inside the first connecting frame. A brush is disposed on one side of the cleaning component facing the corresponding clamping member. A side block is fixed on one side of the cleaning component. The side wall of the first connecting frame is provided with a sliding opening that matches the side block. The outer wall of the side block is attached to the inner wall of the sliding opening, and the side block can slide up and down inside the sliding opening.

[0018] Preferably, the side block can be vertically limited by the support shaft. A base plate is fixed on one side of the first connecting frame, and the bottom of the side block has a support shaft. A through hole adapted to the support shaft is opened on the side block, and the support shaft is slidably connected inside the through hole.

[0019] Preferably, the second return spring can be used to reset the side block that has been released from the restriction. The second return spring is fixed between the bottom of the side block and the top of the base plate. A driving block is fixed to the outer wall of the second limiting shaft. A spiral groove is opened on the outer wall of the second limiting shaft. A protrusion is fixed to the inner wall of the second limiting hole, and the protrusion is slidably connected inside the spiral groove.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. By setting up symmetrical arc-shaped clamping parts and utilizing the meshing transmission between the toothed ring and the first toothed rack, the clamping force is converted into the rotational force of the clamping parts during the clamping process, applying an additional rotational torque to the steel pipe, thereby greatly enhancing the clamping and positioning effect of the steel pipe, ensuring that the steel pipe is stable and not easily loosened during the cold drawing process.

[0022] 2. By setting a linkage cleaning mechanism on the clamping component, when the equipment performs a clamping action, the spiral groove on the second limit shaft cooperates with the protrusion to automatically drive the cleaning component with a brush to slide up and down reciprocally, removing iron filings attached to the surface of the clamping component in real time. This effectively avoids iron filings scratching the steel pipe or affecting the clamping accuracy, and maintains the good working performance of the clamping component for a long time. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the cold drawing mechanism of the present invention;

[0025] Figure 3 This is a schematic diagram of the clamping assembly of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the driving component of the present invention;

[0027] Figure 5 This is a schematic diagram of the cleaning mechanism of the present invention.

[0028] In the picture:

[0029] 10. Processing table; 11. Shaping plate; 12. Shaping hole; 20. Cold drawing mechanism; 21. Clamping assembly; 2101. Clamping component; 2102. First connecting frame; 2103. First limiting shaft; 2104. First limiting hole; 2105. Second connecting frame; 2106. Second limiting shaft; 2107. Second limiting hole; 2108. Support plate; 2109. First return spring; 2110. Hinge component; 2111. Hydraulic cylinder; 2112, moving stage; 22, drive assembly; 2201, connecting frame; 2202, first rack; 2203, gear ring; 2204, drive source; 2205, drive gear plate; 2206, second rack; 30, cleaning mechanism; 31, cleaning component; 32, side block; 33, sliding mouth; 34, base plate; 35, support shaft; 36, second return spring; 37, drive block; 38, spiral groove; 39, protrusion. Detailed Implementation

[0030] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0031] A precision carbon steel pipe for hydraulic cylinders in engineering machinery is disclosed. The pipe has an inner diameter of 4mm-219mm, a wall thickness of 0.5mm-25mm, an outer diameter tolerance of ±0.20mm, an inner diameter tolerance of ±0.20mm, and a wall thickness tolerance controlled within the following ranges: ±0.05mm when 0.5mm ≤ wall thickness < 1mm; ±0.1mm when 1mm ≤ wall thickness < 5mm; and ±0.5mm when 5mm ≤ wall thickness < 10mm. When the wall thickness is 10mm ≤ wall thickness ≤ 25mm, the tolerance is ±1.0mm. The surface roughness of the precision carbon steel pipe is Ra ≤ 1.6μm, the tensile strength is Rm ≥ 390MPa, and the yield strength is ReH ≥ 245MPa. The inner and outer walls of the precision carbon steel pipe are free of oxide layer, and there are no cracks after cold bending, flaring, and flattening. It can withstand 1.5 times the rated working pressure and maintain pressure without leakage. After the surface is rolled, a residual stress layer is formed, which increases the fatigue strength by about 30%.

[0032] A cold drawing process for precision carbon steel tubing used in hydraulic cylinders of engineering machinery includes the following steps:

[0033] S1: Raw material preparation: High-quality hot-rolled seamless steel pipes are selected as billets;

[0034] S2: Pretreatment: Anneal the billet to reduce hardness, straighten it to ensure the tube is straight, and perform tube end processing (such as necking and tapering) to facilitate clamping by the cold drawing machine;

[0035] S3: Surface treatment and lubrication: including pickling: removing oxide scale and rust from the inner and outer surfaces of the pipe; neutralization and washing: removing residual acid; phosphating / saponification: forming a lubricating and load-bearing film on the surface of the steel pipe in preparation for cold drawing.

[0036] S4: Cold drawing: On a cold drawing device, the processed tube blank is drawn into shape through a specially designed die.

[0037] Reference Appendix Figures 1-5 As shown, a cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery includes a processing table 10. A shaping plate 11 is installed on the top of the processing table 10. The shaping plate 11 is set vertically, and a shaping hole 12 is opened in the middle of the shaping plate 11. The steel tube can be inserted into the shaping hole 12 through the shaping hole 12, so that the steel tube can be cold drawn and shaped inside the shaping hole 12.

[0038] The processing table 10 is equipped with a cold drawing mechanism 20, which is used to cold draw and form the steel pipe located on the inner wall of the shaping hole 12.

[0039] The cold drawing mechanism 20 includes a clamping assembly 21 and a driving assembly 22. The driving assembly 22 is used to drive the clamping assembly 21 to clamp and position the steel pipe and to perform cold drawing on the steel pipe.

[0040] The clamping assembly 21 includes symmetrically arranged clamping members 2101. The surface of the clamping member 2101 has an arc-shaped inner groove to adapt to the outer wall shape of the steel pipe. When the two clamping members 2101 approach each other, they can abut against the outer wall of the steel pipe to clamp and fix the steel pipe.

[0041] Both clamping members 2101 are externally mounted with first connecting frames 2102. The first connecting frames 2102 are inverted U-shaped, and their inner cavities correspond. The top of each clamping member 2101 is rotatably connected to the inner top wall of the first connecting frame 2102, and the bottom of each clamping member 2101 is rotatably connected to the inner bottom wall of the first connecting frame 2102. First limiting shafts 2103 are fixed to both the top and bottom of each clamping member 2101. The clamping member 2101 is coaxially arranged with the first connecting frame 2102. The first limiting hole 2104 is provided on the first limiting shaft 2103. The first limiting hole 2104 is coaxially arranged with the corresponding first limiting shaft 2103. The outer wall of the first limiting shaft 2103 is rotatably connected to the hole wall of the corresponding first limiting hole 2104 to limit the first limiting shaft 2103, thereby maintaining the stability of the connected clamping member 2101.

[0042] A second connecting frame 2105 is installed on the opposite side of the two first connecting frames 2102. The second connecting frame 2105 is also inverted U-shaped, and the inner cavity of the second connecting frame 2105 faces the corresponding first connecting frame 2102. The opposite sides of the two first connecting frames 2102 are rotatably connected to a second limiting shaft 2106. A second limiting hole 2107 adapted to the second limiting shaft 2106 is opened on one side of the second connecting frame 2105. The second limiting shaft 2106 and the corresponding second limiting hole 2107 are coaxially arranged, and the outer wall of the second limiting shaft 2106 is attached to the hole wall of the corresponding second limiting hole 2107 so that the second limiting shaft 2106 can slide inside the second limiting hole 2107.

[0043] The second limiting shaft 2106 is rotatably connected to a support plate 2108 at one end away from the first connecting frame 2102. A first return spring 2109 is fixed between the support plate 2108 and the second connecting frame 2105 to support the support plate 2108 so as to drive the released support plate 2108 to return to its original position.

[0044] A hinge 2110 is installed between the two second connecting frames 2105. A moving platform 2112 is installed at the bottom of the hinge 2110. The top of the moving platform 2112 is connected to the bottom of the hinge 2110 by a pin. A hydraulic cylinder 2111 is installed on one side of the moving platform 2112. The piston rod end of the hydraulic cylinder 2111 is connected to one side of the hinge 2110. When the piston rod end of the hydraulic cylinder 2111 pulls the hinge 2110 away from the side of the shaping plate 11, the hinge 2110 will drive the two second connecting frames 2105 to move closer to each other, so that the two clamping members 2101 abut against the surface of the steel pipe to clamp and position it.

[0045] The drive assembly 22 includes connecting frames 2201 symmetrically arranged outside the first connecting frame 2102. Each first connecting frame 2102 has two corresponding connecting frames 2201. A first rack 2202 is installed on the inner wall of the connecting frame 2201. A toothed ring 2203 is fixed on the outer wall of one end of the first limiting shaft 2103 extending out of the first limiting hole 2104. The toothed ring 2203 meshes with the first rack 2202. The first rack 2202, in conjunction with the toothed ring 2203, can drive the first limiting shaft 2103 to rotate. The first limiting shaft 2103 drives the connected clamping member 2101 to rotate, thereby applying rotational force to the abutting steel pipe to improve the clamping strength of the steel pipe.

[0046] A drive source 2204 is installed on the moving stage 2112. A drive gear 2205 is installed at the output end of the drive source 2204. A second rack 2206 is installed on the inner side of the processing table 10, and the drive gear 2205 is meshed with the second rack 2206.

[0047] The clamping member 2101 is provided with a cleaning mechanism 30, which is used to clean the iron filings attached to the surface of the clamping member 2101 in order to maintain the performance of the clamping member 2101.

[0048] The cleaning mechanism 30 includes a cleaning component 31 disposed inside the first connecting frame 2102. The cleaning component 31 is provided with a brush on the side facing the corresponding clamping component 2101, which can clean the clamping surface of the clamping component 2101.

[0049] A side block 32 is fixed on one side of the cleaning component 31. The side wall of the first connecting frame 2102 is provided with a sliding opening 33 that is adapted to the side block 32. The outer wall of the side block 32 is attached to the inner wall of the sliding opening 33, and the side block 32 can slide up and down inside the sliding opening 33.

[0050] A base plate 34 is fixed on one side of the first connecting frame 2102. A support shaft 35 is provided at the bottom of the side block 32. A through hole adapted to the support shaft 35 is provided on the side block 32, and the support shaft 35 is slidably connected inside the through hole. The support shaft 35 can limit the side block 32 in conjunction with the through hole.

[0051] A reset spring 36 is fixed between the bottom of the side block 32 and the top of the base plate 34 to support the side block 32 so as to drive the side block 32 to reset. A drive block 37 is fixed on the outer wall of the second limiting shaft 2106. A spiral groove 38 is opened on the outer wall of the second limiting shaft 2106. A protrusion 39 is fixed on the inner wall of the second limiting hole 2107, and the protrusion 39 is slidably connected inside the spiral groove 38.

[0052] Working principle: When the cold drawing head of the steel pipe passes through the shaping hole 12 on the shaping plate 11 and is located at the cold drawing position on the other side of the shaping plate 11, the drive source 2204 is turned on by the controller. The output end of the drive source 2204 drives the drive gear 2205 to rotate. The drive gear 2205 drives the moving table 2112 to move in the cold drawing area of ​​the processing table 10 through meshing with the second rack 2206. When the moving table 2112 moves to the steel pipe, the piston rod of the hydraulic cylinder 2111 drives one end of the hinge 2110 to slide towards the hydraulic cylinder 2111. The end of the hinge 2110 then drives... The two connected second connecting frames 2105 approach each other. When the clamping member 2101 abuts against the surface of the steel pipe, the clamping member 2101, under the reaction force of the steel pipe, will drive the first connecting frame 2102 to slide towards the second connecting frame 2105. The second limiting shaft 2106 slides inside the corresponding second limiting hole 2107. The first rack 2202, through meshing with the gear ring 2203, drives the first limiting shaft 2103 to rotate inside the first limiting hole 2104. The clamping member 2101 rotates to the direction of the moving table 2112, thereby applying a rotational force to the clamped steel pipe. Meanwhile, the clamping member 2101 can use friction to clean up iron filings from the cold-drawn part of the steel pipe. As the second limiting shaft 2106 slides to the outside of the second limiting hole 2107, the protrusion 39 slides along the extension trajectory of the spiral groove 38. At this time, the second limiting shaft 2106 rotates, which drives the driving block 37 to move downward inside the slide 33. The side block 32 applies downward pressure to the second return spring 36, and the side block 32 drives the cleaning member 31 to move downward. The brush of the cleaning member 31 cleans the clamping surface of the clamping member 2101, and removes the clamping member 2101. As the second limiting shaft 2106 rotates, the iron filings attached to the surface of 01 are removed. When the driving block 37 disengages from the side block 32, the second return spring 36 disengages from the limit and resets. The second return spring 36 then drives the cleaning component 31 to move upward through the side block 32, thereby causing the brush of the cleaning component 31 to repeatedly slide up and down to clean the clamping surface of the clamping component 2101. This allows the cleaned clamping surface of the clamping component 2101 to abut against the surface of the steel pipe. After clamping is completed, the output end of the driving source 2204 drives the driving gear 2205 to rotate in the opposite direction, causing the moving table 2112 to move away from the shaping plate 11, thereby performing cold drawing on the steel pipe.

[0053] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A precision carbon steel pipe for hydraulic cylinders in engineering machinery, characterized in that: The steel pipe has an inner diameter of 4mm-219mm and a wall thickness of 0.5mm-25mm. The outer diameter tolerance is ±0.20mm, and the inner diameter tolerance is also ±0.20mm. The wall thickness tolerance is controlled within the following ranges: ±0.05mm when 0.5mm ≤ wall thickness < 1mm; ±0.1mm when 1mm ≤ wall thickness < 5mm; ±0.5mm when 5mm ≤ wall thickness < 10mm; and ±1.0mm when 10mm ≤ wall thickness ≤ 25mm. The surface roughness Ra of the precision carbon steel pipe is ≤ 1.6μm, the tensile strength Rm ≥ 390MPa, and the yield strength ReH ≥ 245MPa. The precision carbon steel pipe has no oxide layer on its inner and outer walls, and exhibits no cracks during cold bending, flaring, and flattening. It can withstand 1.5 times the rated working pressure without leakage. After roll forming, a residual stress layer is formed on the surface, increasing fatigue strength by approximately 30%.

2. A cold drawing forming process for precision carbon steel tubes used in hydraulic cylinders of engineering machinery, comprising cold drawing forming of the precision carbon steel tubes described in claim 1, characterized in that: Includes the following steps: S1: Raw material preparation: High-quality hot-rolled seamless steel pipes are selected as billets; S2: Pretreatment: Anneal the billet to reduce hardness, straighten it to ensure the tube is straight, and perform tube end processing (such as necking and tapering) so that it can be clamped by the cold drawing machine; S3: Surface treatment and lubrication: including pickling: removing oxide scale and rust from the inner and outer surfaces of the pipe; neutralization and washing: removing residual acid; phosphating / saponification: forming a lubricating and load-bearing film on the surface of the steel pipe in preparation for cold drawing. S4: Cold drawing: On a cold drawing device, the processed tube blank is drawn into shape through a specially designed die.

3. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 2, characterized in that, A precision carbon steel tube for hydraulic cylinders of engineering machinery is cold-drawn using a cold drawing device. The cold drawing device includes a processing table (10), a shaping plate (11) is installed on the top of the processing table (10), and a shaping hole (12) is opened in the middle of the shaping plate (11). The steel tube can slide through the shaping hole (12) for cold drawing and shaping. A cold drawing mechanism (20) is provided on the processing table (10). The cold drawing mechanism (20) includes a clamping component (21) and a driving component (22). The driving component (22) is used to drive the clamping component (21) to clamp and position the steel tube for cold drawing.

4. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 3, characterized in that, The steel pipe is clamped and fixed using a clamping assembly (21). The clamping assembly (21) includes symmetrically arranged clamping members (2101). A first connecting frame (2102) is installed on the outside of each clamping member (2101). A first limiting shaft (2103) is fixed on the top and bottom of each clamping member (2101). A first limiting hole (2104) adapted to the first limiting shaft (2103) is opened on the first connecting frame (2102). The outer wall of the first limiting shaft (2103) is rotatably connected to the hole wall of the corresponding first limiting hole (2104). A second connecting frame (2105) is installed on the opposite side of the two first connecting frames (2102). A second limiting shaft (2106) is rotatably connected to the opposite side of a connecting frame (2102). A second limiting hole (2107) adapted to the second limiting shaft (2106) is opened on one side of the second connecting frame (2105). The second limiting shaft (2106) and the corresponding second limiting hole (2107) are coaxially arranged, and the outer wall of the second limiting shaft (2106) is attached to the hole wall of the corresponding second limiting hole (2107). A support plate (2108) is rotatably connected to the end of the second limiting shaft (2106) away from the first connecting frame (2102). A first return spring (2109) is fixed between the support plate (2108) and the second connecting frame (2105).

5. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 4, characterized in that, The clamping member (2101) is moved to the steel pipe using a moving platform (2112) for clamping and positioning. A hinge (2110) is installed between the two second connecting frames (2105). The moving platform (2112) is installed at the bottom of the hinge (2110). The top of the moving platform (2112) is connected to the bottom of the hinge (2110) by a pin. A hydraulic cylinder (2111) is installed on one side of the moving platform (2112). The piston rod end of the hydraulic cylinder (2111) is connected to one side of the hinge (2110).

6. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 5, characterized in that, The driving component (22) drives the clamping component (2101) to clamp and position the steel pipe. The driving component (22) includes a connecting frame (2201) symmetrically arranged outside the first connecting frame (2102). Each first connecting frame (2102) has two corresponding connecting frames (2201). A first rack (2202) is installed on the inner wall of the connecting frame (2201). A toothed ring (2203) is fixed on the outer wall of one end of the first limiting shaft (2103) extending out of the first limiting hole (2104). The toothed ring (2203) meshes with the first rack (2202).

7. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 5, characterized in that, The steel pipe is cold-drawn by the clamping member (2101) driven by the drive gear (2205) and the second rack (2206). The moving table (2112) is equipped with a drive source (2204), the output end of the drive source (2204) is equipped with a drive gear (2205), the inner side of the processing table (10) is equipped with a second rack (2206), and the drive gear (2205) and the second rack (2206) are meshed together.

8. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 6, characterized in that, The clamping surface of the clamping member (2101) is cleaned by the cleaning mechanism (30). The clamping member (2101) is provided with the cleaning mechanism (30). The cleaning mechanism (30) includes a cleaning member (31) provided inside the first connecting frame (2102). The cleaning member (31) is provided with a brush on one side facing the corresponding clamping member (2101). A side block (32) is fixed on one side of the cleaning member (31). The side wall of the first connecting frame (2102) is provided with a sliding opening (33) that is adapted to the side block (32). The outer wall of the side block (32) is attached to the inner wall of the sliding opening (33). The side block (32) can slide up and down inside the sliding opening (33).

9. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 8, characterized in that, The support shaft (35) can be used to vertically limit the side block (32). The first connecting frame (2102) has a base plate (34) fixed on one side. The bottom of the side block (32) has a support shaft (35). The side block (32) has a through hole that matches the support shaft (35), and the support shaft (35) is slidably connected inside the through hole.

10. The cold drawing forming process for precision carbon steel tubes for hydraulic cylinders of engineering machinery according to claim 9, characterized in that, The second return spring (36) can be used to reset the side block (32) that has been released from the restriction. The second return spring (36) is fixed between the bottom of the side block (32) and the top of the base plate (34). The outer wall of the second limiting shaft (2106) is fixed with a driving block (37). The outer wall of the second limiting shaft (2106) is provided with a spiral groove (38). The inner wall of the second limiting hole (2107) is fixed with a protrusion (39), and the protrusion (39) is slidably connected inside the spiral groove (38).

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