Hydraulic cylinder barrel hole copper welding process

Abstract

The application discloses a kind of hydraulic cylinder cylinder bore copper welding processes, it is related to welding technical field, the welding process includes cylinder bottom welding step, ring groove welding step and ring groove lap step.Cylinder bottom welding step is along the direction of the cylinder bottom end of hydraulic cylinder cylinder to cylinder mouth end, the inner wall of the cylinder bottom end of the inner hole of hydraulic cylinder is welded, until it is welded to interval preset distance with annular groove, and first weld is formed.Ring groove welding step is specifically for welding annular groove, and second weld is formed.Ring groove lap step is specifically for continuing to weld the inner wall of the cylinder bottom end of the inner hole by cylinder bottom welding step, and third weld is formed, one end of third weld is lap joint with first weld, the other end is lap joint with second weld, realize the transition of the junction position of cylinder bottom end inner wall and annular groove.The welding process disclosed in the application is compared with prior art, the number of blowhole points of welded product is greatly reduced, the rework rate is greatly reduced, and the welding quality is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and more specifically, to a copper melting welding process for the inner bore of a hydraulic cylinder. Background Technology

[0002] Mining hydraulic supports are widely used in coal mining. During operation, hard particles easily accumulate on the inner wall of the hydraulic cylinder and the mating surface with the column, causing scratches. Furthermore, corrosive media such as water and H2S can easily mix into the hydraulic oil, leading to rust on the inner wall of the cylinder, affecting the sealing effect and reducing lifting capacity. To address this, a copper alloy welding method is used to melt copper alloy welding wire and deposit a layer of copper alloy material on the inner wall surface of the cylinder to improve the corrosion resistance of the parts and extend their service life.

[0003] In existing technologies, welding is generally performed sequentially from the cylinder port end to the cylinder bottom end or from the cylinder bottom end to the cylinder port end, and a single set of welding parameters is used for different welding positions. However, due to the various welding areas in the cylinder structure, such as regular circular inner holes, deep grooves, and stepped surfaces, and because welding is a complex process influenced by many factors—including welding torch angle, distance from the workpiece, contact tip smoothness, wire length, shielding gas flow rate, wire feed speed, current and voltage, swing distance, and speed—using the same set of welding parameters for different welding areas and weld types can lead to numerous welding defects at the junctions of inner holes and grooves, resulting in a high rework rate.

[0004] Therefore, how to improve the welding quality of the copper fusion welding process in the inner bore of hydraulic cylinders and reduce the rework rate has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a copper fusion welding process for the inner bore of a hydraulic cylinder, so as to improve the welding quality of the copper fusion welding process for the inner bore of a hydraulic cylinder and reduce the rework rate.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A copper-plating welding process for the inner bore of a hydraulic cylinder is used to deposit a layer of copper alloy material on the sidewall surface of the inner bore of the hydraulic cylinder. The sidewall of the inner bore is provided with an annular groove, a threaded extension, and a static sealing mating surface in sequence from the bottom end of the cylinder to the port end, and a stepped surface is formed between the threaded extension and the static sealing mating surface. The process includes the following steps:

[0008] Cylinder bottom welding: Weld the sidewall of the inner hole along the direction from the bottom end of the hydraulic cylinder barrel to the cylinder port end until the welding reaches a predetermined distance from the annular groove and forms a first weld bead;

[0009] Annular groove welding, welding the annular groove, and forming a second weld bead;

[0010] The annular groove overlaps, the sidewall of the inner hole is welded, and a third weld bead is formed, with one end of the third weld bead overlapping the first weld bead and the other end overlapping the second weld bead.

[0011] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, the bottom welding step specifically includes the following steps:

[0012] Preheat welding is performed along the cylinder bottom end to the cylinder opening end of the hydraulic cylinder barrel using CMT welding mode at the first welding speed to weld a preset length, forming a sixth weld bead.

[0013] The welding speed is increased. The CMT welding mode is used to weld along the cylinder bottom end to the cylinder mouth end of the hydraulic cylinder barrel at a second welding speed until the cylinder is spaced at a preset distance from the annular groove, and a seventh weld bead is formed. The seventh weld bead is connected to the sixth weld bead. The sixth weld bead and the seventh weld bead form the first weld bead. The second welding speed is greater than the first welding speed.

[0014] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, the preset length is 50mm-100mm, and the first welding speed is 280mm / min-300mm / min; and / or,

[0015] The second welding speed is 430mm / min-450mm / min.

[0016] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, the preset distance is 70mm-80mm.

[0017] Optionally, the above-mentioned copper welding process for the inner bore of the hydraulic cylinder barrel further includes the following steps:

[0018] Step welding, welding the step surface, and forming a fourth weld pass;

[0019] The cylinder bore is welded, and the static sealing mating surface is welded from the bottom end of the hydraulic cylinder barrel toward the cylinder bore end, forming a fifth weld pass, which is connected to the fourth weld pass.

[0020] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, the step welding step is located between the annular groove welding step and the annular groove overlapping step, and both the annular groove welding step and the step welding step are performed in pulse mode.

[0021] Optionally, in the above-mentioned copper melting welding process of the inner hole of the hydraulic cylinder barrel, the specific welding speed of the annular groove welding step and the step welding step is 320mm / min-340mm / min, and the welding current is 200A.

[0022] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, the cylinder port end of the inner bore is chamfered, and the fifth weld extends to the surface of the chamfer.

[0023] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, a detection step is included after the cylinder port welding step. The detection step specifically involves detecting whether there are pores on the welding surfaces of the first weld, the second weld, the third weld, the fourth weld, and the fifth weld. If pores are present, the welding is re-welded.

[0024] Optionally, in the above-mentioned copper welding process for the inner bore of the hydraulic cylinder, an inner wall cleaning step is included before the bottom welding step. Specifically, the inner wall cleaning step involves wiping the side wall of the inner bore with foam cotton soaked in alcohol.

[0025] The present invention provides a copper-plated welding process for the inner bore of a hydraulic cylinder, used to deposit a layer of copper alloy material on the sidewall surface of the inner bore of a hydraulic cylinder. The sidewall of the inner bore, from the bottom end to the opening end, is sequentially provided with an annular groove, a threaded extension, and a static sealing mating surface, with a stepped surface formed between the threaded extension and the static sealing mating surface. This copper-plated welding process for the inner bore of the hydraulic cylinder includes a bottom welding step, an annular groove welding step, and an annular groove overlap step. Specifically, the bottom welding step involves welding the inner wall of the bottom end of the hydraulic cylinder's inner bore along the direction from the bottom end to the opening end until a predetermined distance is reached between the inner wall and the annular groove, forming a first weld bead. The predetermined distance provides sufficient working space for reliable overlap between subsequent weld bead and the first weld bead. The annular groove welding step specifically involves welding the annular groove. This welding process creates a second weld bead, which completely covers the annular groove to facilitate the subsequent overlap between the second and first weld beads, ensuring a tight fit between the weld structure at the junction of the cylinder bottom inner wall and the annular groove. The annular groove overlap step specifically involves continuing the welding of the inner wall of the cylinder bottom from the cylinder bottom welding step. This welding process creates a third weld bead, with one end overlapping the first weld bead and the other end overlapping the second weld bead, achieving a transition at the junction of the cylinder bottom inner wall and the annular groove.

[0026] Compared with existing technologies, the copper fusion welding process for the inner bore of the hydraulic cylinder provided by this invention involves welding the inner wall of the cylinder bottom end, the annular groove, and the junction of the inner wall of the cylinder bottom end and the annular groove in sequence. This welding sequence ensures high welding quality at the junction of the inner wall of the cylinder bottom end and the annular groove. Experimental verification shows that the copper fusion welding process for the inner bore of the hydraulic cylinder provided by this invention significantly reduces the number of porosity points in the welded product, greatly reduces the rework rate, and significantly improves the welding quality compared with the welding process of existing technologies. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0028] Figure 1 This is a flowchart of the first hydraulic cylinder barrel inner hole copper melting welding process disclosed in the embodiments of the present invention;

[0029] Figure 2 This is a flowchart of the second hydraulic cylinder bore copper melting welding process disclosed in an embodiment of the present invention;

[0030] Figure 3 This is a flowchart of the third hydraulic cylinder barrel inner hole copper melting welding process disclosed in the embodiments of the present invention;

[0031] Figure 4 This is a flowchart of the fourth hydraulic cylinder barrel inner hole copper melting welding process disclosed in the embodiments of the present invention;

[0032] Figure 5 The attached diagram shows the process structure before copper melting in the inner bore of the hydraulic cylinder as disclosed in this embodiment of the invention.

[0033] Figure 6 for Figure 5 Enlarged view of the structure at point C;

[0034] Figure 7 The attached drawing shows the structure of the finished product of copper melting in the inner bore of the hydraulic cylinder as disclosed in the embodiment of the present invention.

[0035] Wherein, 100 is the cylinder barrel of the hydraulic cylinder, 110 is the bottom end of the cylinder, 111 is the inner wall of the bottom end of the cylinder, 120 is the cylinder port end, 121 is the threaded extension, 122 is the static sealing mating surface, 123 is the chamfered structure, 124 is the annular groove, and 125 is the lead angle. Detailed Implementation

[0036] The core of this invention is to disclose a copper fusion welding process for the inner bore of a hydraulic cylinder, so as to improve the welding quality of the copper fusion welding process for the inner bore of the hydraulic cylinder and reduce the rework rate.

[0037] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the invention as described in the claims. Additionally, the complete contents of the structures represented in the embodiments below are not limited to those necessary for the solution of the invention as described in the claims. It should be noted that, for ease of description, only the parts relevant to the relevant application are shown in the drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0038] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0039] Combination Figure 5 and Figure 6 Due to the structural form of the hydraulic cylinder barrel 100, an annular groove 124 needs to be pre-machined between the threaded extension 121 and the lead angle 125 at the cylinder port end 120. A stepped surface is formed at the junction of the static sealing mating surface 122 and the threaded extension 121 of the hydraulic cylinder barrel 100. That is, along the direction from the bottom end 110 of the hydraulic cylinder barrel 100 to the cylinder port end 120, an annular groove 124, a threaded extension 121 and a static sealing mating surface 122 are sequentially provided on the side wall of the inner hole of the hydraulic cylinder. A stepped surface is formed between the threaded extension 121 and the static sealing mating surface 122. The structure of the annular groove 124 and the stepped surface forms a different welding area from the regular circumferential side wall of the inner hole.

[0040] The copper welding process for the inner bore of the hydraulic cylinder barrel disclosed in this invention is used to deposit a layer of copper alloy material on the inner sidewall surface of the hydraulic cylinder barrel 100, combined with... Figure 1 The copper welding process for the inner bore of the hydraulic cylinder includes the following steps:

[0041] S10, Cylinder bottom welding;

[0042] Along the direction from the bottom end 110 of the hydraulic cylinder barrel 100 to the cylinder port end 120, the inner wall 111 of the bottom end of the hydraulic cylinder inner hole is welded until it is welded to a predetermined distance from the annular groove 124, and the welding process forms a first weld bead.

[0043] Specifically, the inner wall of the hydraulic cylinder barrel 100, which is mounted on the inner hole copper melting equipment and placed horizontally and stably, is welded starting from the bottom end 110 of the cylinder and stopping when it is close to the annular groove 124. The preset distance setting can reserve enough working space for the reliable overlap of the subsequent weld and the first weld.

[0044] S20, circumferential groove welding;

[0045] The annular groove 124 is welded, and this welding process forms a second weld bead. Specifically, the second weld bead covers the entire circumference of the annular groove 124 to facilitate the subsequent overlap of the second weld bead with the first weld bead, ensuring that the weld structure at the junction of the inner wall 111 at the bottom of the cylinder and the annular groove 124 is tightly fitted.

[0046] S30, circumferential groove overlap;

[0047] Following S10, continue welding the inner wall 111 at the bottom of the cylinder bore. This welding process forms a third weld bead, with one end of the third weld bead overlapping the first weld bead and the other end overlapping the second weld bead. That is, the connection between S10 and S20 is completed at the preset distance of S10, realizing the transition at the junction of the inner wall 111 at the bottom of the cylinder bore and the annular groove 124.

[0048] Compared with the prior art, the copper fusion welding process for the inner bore of the hydraulic cylinder disclosed in this embodiment of the invention adopts the following order for welding the inner bore of the hydraulic cylinder: the inner wall 111 at the bottom of the cylinder, the annular groove 124, and the junction of the inner wall 111 at the bottom of the cylinder and the annular groove 124. This welding sequence ensures that the welding at the junction of the inner wall 111 at the bottom of the cylinder and the annular groove 124 has high quality. Moreover, experimental verification shows that compared with the welding process of the prior art, the copper fusion welding process for the inner bore of the hydraulic cylinder disclosed in this embodiment of the invention greatly reduces the number of porosity points in the welded product, greatly reduces the rework rate, and significantly improves the welding quality.

[0049] like Figure 2 As shown, in a specific embodiment of the present invention, S10 specifically includes a preheating welding step and a speed-up welding step.

[0050] S11, Preheat welding;

[0051] The hydraulic cylinder barrel 100 is welded in the direction from the bottom end 110 to the port end 120 using CMT welding mode at the first welding speed for a preset length, and the welding process forms a sixth weld bead.

[0052] CMT welding, or cold metal transfer welding technology, is a new type of welding process technology that eliminates weld spatter. Compared with pulsed arc and short-circuit transfer arc welding, CMT welding reduces the amount of weld spatter in steel by up to 99% and has a lower heat input. Under the same weld quality and penetration requirements, its welding speed can be increased by 10 times.

[0053] S12, Speed-up welding;

[0054] The hydraulic cylinder barrel 100 is welded in the direction from the bottom end 110 to the opening end 120 using CMT welding mode at the second welding speed to a predetermined distance from the annular groove. The welding process forms a seventh weld bead, and the sixth and seventh weld beads are connected to form a first weld bead. The second welding speed is greater than the first welding speed.

[0055] In S11, a lower welding line speed is used to preheat the hydraulic cylinder barrel 100 during the welding process. Then, in S12, the welding line speed is increased. The welding processes of S11 and S12 together form the first weld bead, meaning that the welding processes of S11 and S12 can be continuous and uninterrupted.

[0056] The preset length is 50mm-100mm, the first welding speed is 280mm / min-300mm / min, and the second welding speed is 430mm / min-450mm / min.

[0057] In one specific embodiment, the first welding speed is 290 mm / min, the second welding speed is 440 mm / min, and the welding currents of S11 and S12 are both 225 A, the pitch is 11 mm, and the swing distance is 12 mm.

[0058] It should be noted that the welding parameters in the welding process are a range of values, not fixed values. The arc initiation, welding, and arc termination during the welding process will fluctuate around the set parameter values.

[0059] Specifically, S12 is welded to a distance of 70mm-80mm from the annular groove 124, i.e., the preset distance is 70mm-80mm.

[0060] The length reserved in S12 can be used to overlap the second weld bead covering the annular groove 124 with the first weld bead in S30, so that a complete ring of fitting weld bead is formed at the junction of the inner wall 111 at the bottom of the cylinder and the annular groove 124. This avoids the problem of poor welding effect caused by the weld bead not fitting due to sequential welding of the inner wall 111 at the bottom of the cylinder, the junction of the inner wall 111 at the bottom of the cylinder and the annular groove 124, and the annular groove 124.

[0061] The copper fusion welding process for the inner bore of the hydraulic cylinder disclosed in this embodiment of the invention achieves the welding of the stepped surface and the static sealing mating surface 122 through a step welding step and cylinder port welding.

[0062] S40, step welding;

[0063] The stepped surface formed by the welded static sealing mating surface 122 and the threaded extension 121 is formed, and the welding process forms a fourth weld pass, wherein the position of the fourth weld pass is connected to the position of the static sealing mating surface 122 (stop), and the fourth weld pass can serve as the first pass of the stop welding (S50).

[0064] S50, cylinder port welding;

[0065] A static sealing mating surface 122 is welded from the bottom end 110 of the hydraulic cylinder barrel 100 towards the cylinder port end 120, i.e., the stop position of the hydraulic cylinder barrel 100. This welding process forms a fifth weld pass, one end of which overlaps or connects with the fourth weld pass. Welding stops at the end face of the cylinder port end 120, finally resulting in the following... Figure 7 The hydraulic cylinder barrel structure is shown.

[0066] That is, as Figure 1 As shown, welding is performed in the following order: inner wall 111 at the bottom of the cylinder, annular groove 124, stepped surface, the junction of inner wall 111 at the bottom of the cylinder and annular groove 124, and static sealing mating surface 122. It should be noted that the welding order of S20 and S40 can be changed without affecting the welding effect.

[0067] Both S20 and S40 can be used for welding in pulse mode. The pulse mode has a high voltage, which makes it less likely to produce welding defects. Furthermore, the welding parameters selected for S20 and S40 can be consistent. By selecting appropriate parameters, the welding effect on the annular groove 124 and the stepped surface can be guaranteed at the same time, reducing the number of times the operator switches welding modes.

[0068] Specifically, S20 uses a pulse mode and a non-oscillating welding method to fill the annular groove 124. Pulse welding has good arc ignition performance, less welding spatter, and good weld formation. At the same time, the welding voltage is high and the heat input is large. The non-oscillating welding method can reduce the probability of uncleanliness or dirt accumulation inside and at the root of the annular groove 124.

[0069] In a specific embodiment of the present invention, the welding speeds of S20 and S40 are both 330 mm / min (320 mm / min-340 mm / min), and the welding current is 200 A.

[0070] Combination Figure 5The cylinder port end of the hydraulic cylinder barrel 100 is a chamfered structure 123. S50 is welded to the position of the chamfered structure 123, that is, the fifth weld extends to the chamfered surface. The end face of the cylinder port end 120 of the hydraulic cylinder barrel 100 does not need to be welded.

[0071] During the welding of the static sealing mating surface 122, first move the welding torch to the stop position, and then weld from the lap position with the fourth weld pass along the direction from the bottom end 110 of the hydraulic cylinder barrel 100 to the cylinder port end 120 to the chamfered structure 123. Furthermore, the hydraulic cylinder barrel 100 is well heated during S50, and the same welding parameters as in S12 can be used directly for welding.

[0072] For example, welding was performed using CMT mode with a welding speed of 440 mm / min, a welding current of 225 A, a pitch of 11 mm, and a swing distance of 12 mm.

[0073] It should be noted that there are generally two working conditions during the weld overlap process between various steps. The first is the weld overlap immediately after welding is interrupted. At this time, the hydraulic cylinder is in a preheated state, so you only need to rotate the hydraulic cylinder in the opposite direction by 20mm-25mm, bypass the arc crater, and directly ignite the weld. The second is after welding has been stopped for a long time and the temperature of the hydraulic cylinder has dropped (such as during a power outage or lunch break). When welding is resumed, it is necessary to ensure that the current and voltage remain unchanged and reduce the welding speed to start welding. By reducing the welding speed, a higher heat output can be achieved in a short unit of time, which can achieve the preheating effect of the hydraulic cylinder and reduce the welding defects that may exist at the weld overlap.

[0074] like Figure 4 As shown, after S50, there is also a detection step (S60). Specifically, S60 is to detect whether there are pores on the welding surfaces and lap positions of the first weld bead, the second weld bead, the third weld bead, the fourth weld bead, and the fifth weld bead. If there are pores, they need to be re-welded.

[0075] Specifically, the presence of porosity can be detected by strong light irradiation or visual inspection, or by spraying a weld flaw detection developer. If porosity is detected, the weld in the affected area is removed and re-welded.

[0076] Combination Figure 3 Before S50, there is also an inner wall cleaning step (S00), which specifically involves wiping the sidewalls of the inner hole (including the annular groove 124 and the stepped surface) with foam cotton soaked in alcohol to keep them clean and reduce the probability of copper welding defects in the inner hole.

[0077] Specifically, the hydraulic cylinder barrel 100 is first hoisted by a hook or other tooling, and then the cylinder diameter and wall thickness of the hydraulic cylinder barrel 100 are checked to see if they meet the requirements. After they meet the requirements, the inner wall of the cylinder barrel to be melted is wiped. When the cylinder barrel is too long, an extended tooling can be used to wipe the inner wall.

[0078] Experimental verification showed that, using existing welding processes, a total of 213 internal hole cladding parts and 43 sets of internal wall spot-repair parts were obtained, while using the welding process disclosed in this embodiment of the invention, a total of 340 internal hole cladding parts and 21 internal wall spot-repair parts were obtained. Compared with existing technologies, the welding process disclosed in this embodiment of the invention reduces the rework rate of internal holes from 20% to 6.2%, and the number of pores at the annular groove 124, the step surface, and the junction is reduced from multiple to 1-2, significantly reducing the rework rate and demonstrating a significant improvement in welding quality.

[0079] The terms "first" and "second," etc., used in the specification and claims of this invention are used to distinguish different objects, not to describe a specific order, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may include steps or units not listed, but rather steps or units not listed. Additionally, in the description of embodiments in this application, "a plurality of" means two or more.

[0080] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A copper-plating welding process for the inner bore of a hydraulic cylinder, used to deposit a layer of copper alloy material onto the sidewall surface of the inner bore of the hydraulic cylinder, wherein the sidewall of the inner bore is provided sequentially from the bottom end of the cylinder to the port end with an annular groove, a threaded extension, and a static sealing mating surface, and a stepped surface is formed between the threaded extension and the static sealing mating surface, characterized in that... Including the following steps: Cylinder bottom welding: Weld the sidewall of the inner hole along the direction from the bottom end of the hydraulic cylinder barrel to the cylinder port end until the welding reaches a predetermined distance from the annular groove and forms a first weld bead; Annular groove welding, welding the annular groove, and forming a second weld bead; The annular groove overlaps, the sidewall of the inner hole is welded, and a third weld bead is formed, with one end of the third weld bead overlapping the first weld bead and the other end overlapping the second weld bead; The specific steps of the cylinder bottom welding process include: Preheat welding is performed along the cylinder bottom end to the cylinder opening end of the hydraulic cylinder barrel using CMT welding mode at the first welding speed to weld a preset length, forming a sixth weld bead. The welding speed is increased. The CMT welding mode is used to weld along the direction from the bottom end of the hydraulic cylinder barrel to the cylinder opening end at the second welding speed until the annular groove is spaced at the preset distance, and a seventh weld bead is formed. The seventh weld bead is connected to the sixth weld bead. The sixth weld bead and the seventh weld bead form the first weld bead. The second welding speed is greater than the first welding speed. The preset length is 50mm-100mm, and the first welding speed is 280mm / min-300mm / min; The second welding speed is 430 mm / min - 450 mm / min; The preset distance is 70mm-80mm.

2. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 1, characterized in that, It also includes the following steps: Step welding, welding the step surface, and forming a fourth weld pass; The cylinder bore is welded, and the static sealing mating surface is welded from the bottom end of the hydraulic cylinder barrel toward the cylinder bore end, forming a fifth weld pass, which is connected to the fourth weld pass.

3. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 2, characterized in that, The step welding step is located between the annular groove welding step and the annular groove overlapping step, and both the annular groove welding step and the step welding step are performed using a pulse mode.

4. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 2, characterized in that, The specific welding speed for the annular groove welding step and the step welding step is 320mm / min-340mm / min, and the welding current is 200A.

5. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 2, characterized in that, The inner bore has a chamfered end, and the fifth weld extends to the chamfered surface.

6. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 2, characterized in that, The cylinder welding step is followed by an inspection step, which specifically involves checking whether there are pores on the welding surfaces of the first weld bead, the second weld bead, the third weld bead, the fourth weld bead, and the fifth weld bead. If pores are present, the welding is repeated.

7. The copper welding process for the inner bore of the hydraulic cylinder as described in claim 1, characterized in that, The cylinder bottom welding step is preceded by an inner wall cleaning step, which specifically involves wiping the side wall of the inner hole with foam cotton soaked in alcohol.

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