A 12m long oil casing inner wall full-area laser cladding system

Abstract

The invention relates to the technical field of laser cladding, and specifically to a full-area laser cladding system for the inner wall of a 12m-long oil casing, comprising: a laser; a laser head; a powder feeding system, used for conveying spherical nickel-based alloy powder with a melting point in the temperature range of 1300°C-1400°C and a particle size of 53μm-150μm to the laser head and laser cladding it on the inner wall of a pipe; a workpiece rotating system, used for controlling the rotation speed of the pipe to be clad to 25° / s-55° / s, and the rotation speed accuracy reaches 0.5° / s; a laser head walking system, used for controlling the laser head to move axially inside the pipe; a water cooling system, used for fully cooling the laser, an optical cable and a laser head; the system of the invention can ensure that the laser scanning speed is in the range of 100mm / s-150mm / s through the mutual cooperation between various subsystems, and can work continuously and stably for more than 20 hours.

Description

Technical Field

[0001] The invention relates to the technical field of laser cladding, and in particular to a full-area laser cladding system for the inner wall of a 12m-long oil casing. Background Art

[0002] Salt cave compressed air energy storage is a large-capacity physical energy storage technology that uses underground salt caverns to store gas. It compresses air into salt caverns with electricity during low-power consumption, and releases compressed air to generate electricity during peak power consumption, thereby achieving peak-to-valley shaving and valley-filling for the power grid, improving the grid regulation capacity and new energy consumption capacity. It is a large-scale clean physical energy storage technology with great development prospects and advantages such as large capacity, long life, safety and environmental protection. However, there are many saturated salt water in salt caverns that are highly corrosive to metal materials. The wellbore material used for salt cavern gas storage pipelines must have high corrosion resistance. For example, the corrosion resistance in saturated salt water at 60°C is required to be: the uniform corrosion rate is less than 0.01mm / year, and the maximum pitting rate is less than 0.015mm / year. At the same time, the minimum strength (tensile strength, internal pressure resistance, and external extrusion strength) of the pipeline shall not be lower than the relevant provisions of API TR 5C3. The strength of commonly used N80 seamless steel pipes (commonly known as N80 oil pipes) and P110 seamless steel pipes (commonly known as P110 casings) can meet the requirements, but their corrosion resistance is far from meeting the requirements. According to the requirements, in order to meet the corrosion resistance requirements, alloys with a composition of Cr+Ni+Mo content higher than 55% are required. If Ni-based alloy pipes are used, the strength and corrosion resistance can meet the requirements, but the price is expensive.

[0003] For this purpose, N80 seamless steel pipes and P110 seamless steel pipes with appropriate wall thickness and strength that meet the requirements are generally selected as the base material. Corrosion-resistant alloys are laser-clad on the inner wall in contact with the corrosive medium to produce inner-lined corrosion-resistant composite steel pipes.

[0004] In addition, the depth of salt caverns is usually more than 500m, which requires that the existing seamless steel pipes (commonly known as oil pipes and casings in the oil industry) with length specifications of about 12m be connected with hoops to meet the requirements of more than 500m. The primary problem encountered here is that for the inner wall of the 12m long, 315mm± (N80 with specifications of 339.7×12.19) oil pipe and the inner wall of the 443mm± (P110 with specifications of 473.08×14.8) casing, the uniform laser cladding thickness of 0.8mm±0.1mm Ni20kSJG alloy cladding layer is required. This is equivalent to 10.8m 2 and at 15.31m 2 There is no precedent so far for uniform laser cladding of Ni20CrMokSJG alloy coating with a thickness of 0.8mm±0.1mm on the inner wall of the pipe.

[0005] According to the conventional laser cladding, the laser scanning speed is mostly in the range of 6mm / s-20mm / s, and the cladding efficiency is low. It takes about 229 hours (laser scanning speed is 6mm / s) to 68 hours (laser scanning speed is 20mm / s) to laser clad the entire inner wall of a 10m long oil pipe with an inner diameter of 315mm± (N80 with specifications of 339.7×12.19). The efficiency is too low.

[0006] The Fraunhofer-Institut für Laser technikILT and RWTH Aachen University proposed the technical concept of ultra-high-speed laser cladding in 2012, and launched the ultra-high-speed laser cladding (Extreme high-speed laser cladding (EHLA), also called ultra-high-speed laser cladding (UHSLC)) in 2017 in cooperation with the German laser manufacturer Laserline. The laser scanning speed of ultra-high-speed laser cladding is 20m / min (the laser scanning speed is higher than 333mm / s), and the cladding efficiency is higher than 200cm 2 / min. However, the thickness of the ultra-high-speed laser cladding layer is mostly 0.1-0.2mm. It can be seen that the cladding efficiency of ultra-high-speed laser cladding is high, but the cladding layer is thin, and rapid laser cladding of the inner wall around ID300mm has not yet been seen.

[0007] In order to ensure uniform laser cladding over a large area (such as the inner wall of a 12m long oil pipe with an inner diameter of 315mm± and the inner wall of a casing with an inner diameter of 443mm±), a stable laser cladding system is required; therefore, the present application aims to provide a laser scanning speed of 100mm / s-150mm / s, a cladding layer thickness of 0.5mm-1.2mm for nickel-based alloys, and a laser cladding system for the inner wall of a 12m long oil casing, which ensures the stability of the laser cladding process, good metallurgical bonding between the laser cladding layer and the substrate, uniform thickness, and a smooth surface that meets various technical requirements. Summary of the invention

[0008] The purpose of the present invention is to provide a full-area laser cladding system for the inner wall of a 12m long oil casing to improve the above-mentioned technical problems.

[0009] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0010] A 12m long oil casing inner wall full-area laser cladding system includes:

[0011] Laser: a multi-mode continuous wave laser with an output power of 6kW and a wavelength of 1080nm is selected;

[0012] The laser head uses a laser beam internal focusing-reflection output coaxial powder feeding laser head so that the high energy density laser beam output from the laser head nozzle installed on the bracket has a laser beam diameter change of ≤0.5mm within a range of 15mm-25mm from the nozzle end;

[0013] A powder feeding system is used to feed spherical nickel-based alloy powder with a melting point in the temperature range of 1300°C-1400°C and a particle size of 53μm-150μm to the laser head and laser-clad the powder on the inner wall of the pipe;

[0014] Workpiece rotation system, used to control the rotation speed of the pipe to be clad to 25° / s -55° / s, with a rotation speed accuracy of 0.5° / s, thereby controlling the laser scanning speed;

[0015] Laser head travel system, used to control the laser head to move axially inside the pipe;

[0016] The water cooling system is used to fully cool the laser, optical cable, and laser head.

[0017] As a preferred solution of the present invention: the powder feeding system uses a 5L volume rotary disk quantitative-carrier gas conveying powder feeder, and feeds powder to the laser head through a powder feeding pipeline, and the powder feeding carrier gas is argon.

[0018] As a preferred solution of the present invention, the cooling medium of the water cooling system is pure water, and the cooling parameters are as follows:

[0019] For laser: cooling water temperature 24℃±1℃ water temperature, input pressure: 4-6Bar, flow rate: ≥52L / min;

[0020] For optical cables: cooling water temperature: 10-25°C, water inlet pressure: 4-6Bar, flow rate: 2L / min;

[0021] For laser head: cooling water temperature: 10-25℃, water inlet pressure: 4-6Bar, flow rate: 8L / min.

[0022] As a preferred solution of the present invention: it also includes an argon system, which is used to provide powder delivery carrier gas on the one hand, and on the other hand, is used to perform argon purge protection on the output mirror in the coaxial powder delivery laser head with focusing-reflection output in the laser beam before the laser head is turned on, and also to realize argon protection for the laser cladding area.

[0023] As a preferred solution of the present invention: it also includes a cold air blower, which is used to blow the inner hole of the pipe with air with a cooling capacity of 3.5kW and a delivery temperature of 10°C during the laser cladding process to achieve heat dissipation by blowing air inside the pipe during the laser cladding process.

[0024] As a preferred solution of the present invention: the surface roughness of the reflective lens in the laser beam internal focusing-reflection output coaxial powder feeding laser head is less than 5nm.

[0025] As a preferred solution of the present invention: the laser head travel system comprises an extension rod, one end of which is fixed to a support support on a machine tool table through a bracket, and a laser head support device for fixing the laser head is installed at the other end of the extension rod, and the extension rod controls the axial movement of the laser head along the extension rod through a CNC-servo motor-ball screw feed system;

[0026] Among them, the laser head bracket ensures that the distance from the nozzle end of the laser head to the inner wall of the cladding pipe is H=f+fh during the laser cladding process, where f is the distance from the intersection point of the laser head powder feeding to the nozzle end, and fh is the distance from the intersection point of the laser head powder feeding to the inner wall surface of the cladding pipe. The preferred solution is: H=18mm±0.5mm, fh=1.0mm-4.0mm.

[0027] As a preferred solution of the present invention: the extension rod is made of aluminum profile with model number 8-800800A and material 6063-T5.

[0028] As a preferred solution of the present invention: the laser head supporting device includes a bracket and a supporting roller, the laser head is installed on the bracket, and the supporting rollers are installed at both ends of the bracket. During the cladding process, as the clad pipe rotates, the supporting rollers move along the inner wall of the pipe, so that the laser beam output from the laser head is scanned at a certain speed to achieve laser cladding, and H can be adjusted by adjusting the diameter of the supporting roller and the distance between the two supporting rollers.

[0029] As a preferred solution of the present invention: the workpiece rotation system includes a CNC machine tool, a screw transmission system arranged on the CNC machine tool, and a servo motor for controlling the rotation of the screw of the screw transmission system.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The system of the present invention can ensure that the laser scanning speed is in the range of 100mm / s-150mm / s through the mutual cooperation between various subsystems, and can work continuously and stably for more than 20 hours. The laser cladding process is stable, the laser cladding layer has good metallurgical bonding with the substrate, and the thickness of the laser cladding layer is uniform and greater than 0.8mm, thereby achieving laser cladding of the inner wall of a large-line long tube with a smooth surface that meets various technical requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0033] Figure 1 It is a system schematic diagram of the present invention.

[0034] Figure 2 It is a schematic diagram of the connection between the stable support structure and the laser head of the present invention.

[0035] Reference numerals:

[0036] 1. Laser head; 2. Laser; 3. Powder feeding system; 4. Workpiece rotating system; 5. Laser head walking system; 6. Water cooling system; 7. Argon system; 8. Inner wall of pipe; 511. Bracket; 512. Support roller; 11. Nozzle. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The following first describes the concepts involved in the present application in conjunction with the accompanying drawings. It should be noted that the following description of each concept is only to make the content of the present application easier to understand, and does not limit the scope of protection of the present application; at the same time, the embodiments and features in the embodiments of the present application can be combined with each other in the absence of conflict. The present application will be described in detail with reference to the accompanying drawings and in conjunction with the embodiments.

[0039] refer to Figure 1-Figure 2 As shown, the present invention provides a 12m long oil casing inner wall full-area laser cladding system, comprising:

[0040] Laser 2, a multi-mode continuous wave laser with an output power of 6kW and a wavelength of 1080nm is selected;

[0041] Laser head 1, using laser beam cohesion-reflection output coaxial powder feeding laser head 1 so that the laser beam with high energy density output from the nozzle of laser head 1 changes in diameter by ≤0.5mm within the range of 15mm-25mm from the nozzle end;

[0042] A powder feeding system 3 is used to feed spherical nickel-based alloy powder with a melting point in the temperature range of 1300°C-14°C and a particle size of 53μm-150μm to the laser head 1 and laser clad the powder on the inner wall of the pipe;

[0043] Workpiece rotation system 4, used to control the rotation speed of the pipe to be clad to 25° / s-55° / s, with a rotation speed accuracy of 0.5° / s, thereby controlling the laser scanning speed;

[0044] The laser head travel system 5 is used to control the laser 2-optical fiber + QBH interface-laser head 1 system to move axially inside the pipe; in this embodiment, the steel pipe moves 0.5mm-2mm per rotation, that is, 0.5mm-2mm / r;

[0045] The water cooling system 6 is used to fully cool the laser 2 , the optical cable, and the laser head 1 .

[0046] The powder delivery system 3 uses a 5L rotary disk quantitative-carrier gas delivery powder feeder, and delivers powder to the laser head 1 through a powder delivery pipeline, and the powder delivery carrier gas is argon.

[0047] The cooling medium of the water cooling system 6 is pure water, and the cooling parameters are as follows:

[0048] For laser 2: cooling water temperature 24℃±1℃ water temperature, input pressure: 4-6Bar, flow rate: ≥52L / min;

[0049] For optical fiber: cooling water temperature: 10-25℃, water inlet pressure: 4-6Bar, flow rate: 2L / min;

[0050] For laser head 1: cooling water temperature: 10-25℃, water inlet pressure: 4-6Bar, flow rate: 8L / min.

[0051] It also includes an argon system 7, which is used to provide powder delivery carrier gas on the one hand, and on the other hand, to perform argon purge protection on the output mirror in the laser beam focusing-reflection output coaxial powder delivery laser head 1 before the laser head 1 is turned on.

[0052] It also includes a cold air blower, which is used to blow air with a cooling capacity of 3.5kW and a delivery temperature of 10°C to purge the inner hole of the pipe during the laser cladding process, so as to achieve heat dissipation by blowing air inside the pipe during the laser cladding process.

[0053] Wherein, the surface roughness of the reflective lens in the laser beam cohesion-reflection output coaxial powder feeding laser head 1 is less than 5nm.

[0054] The laser head travel system 5 includes an extension rod, one end of which is fixed to the machine tool table through a bracket, and the other end of which is installed with a laser head support device for fixing the laser-optical fiber+QBN interface-laser head system, and the extension rod controls the axial movement of the extension rod on which the laser head is installed through a numerical control-servo motor-ball screw feed system;

[0055] Among them, during the laser cladding process, the distance from the nozzle end of the laser head 1 to the inner wall of the cladding pipe is set to H = f + fh, where f is the distance from the intersection point of the powder feeding of the laser head 1 to the nozzle end, and fh is the distance from the intersection point of the powder feeding of the laser head 1 to the inner wall surface of the cladding pipe. The preferred solution is: H = 18mm ± 0.5mm, fh = 1.0mm-4.0mm.

[0056] The extension rod is made of aluminum profile with model 8-800800A and material 6063-T5.

[0057] The laser head supporting device includes a bracket 511 and a supporting roller 512. The laser head 1 is mounted on the bracket 511. The supporting rollers 512 are mounted at both ends of the bracket 511. During the cladding process, as the clad pipe rotates, the supporting rollers 512 move along the inner wall of the pipe, so that the laser beam output from the laser head is scanned at a certain speed to achieve laser cladding. The diameter of the supporting roller 512 and the distance between the two supporting rollers 512 can be adjusted to achieve H = 18 mm ± 0.5 mm required by this work.

[0058] The workpiece rotating system 4 includes a numerically controlled machine tool, a screw transmission system arranged on the numerically controlled machine tool, and a servo motor for controlling the rotation of the screw of the screw transmission system.

[0059] 1) The computer center control system gives instructions to control the pressure and flow of cooling water in the water cooling system 6; and realizes the control of water cooling and temperature during the cooling water circulation process. This can achieve effective cooling of the laser and laser head 1 and long-term normal operation. Its circuit-switch system must ensure that the laser head 1 can only start working when the computer center control system confirms that the water cooling system 6 is working normally.

[0060] 2) Laser head system: Fiber laser-fiber laser output is provided by the laser production unit. The computer center control system in this application gives instructions: given laser power, laser start and shut down; using the QBH interface to ensure that the laser output reaches the laser head 1 through the optical fiber, and the required laser beam is output through beam-focusing-reflection in the laser head 1. The computer center control system designed in this application commands and controls the water cooling protection of the laser head 1 and the argon purge protection of the output mirror.

[0061] 3) The present application proposes the use of a laser beam internal focusing-reflection output coaxial powder feeding laser head 1.

[0062] 4) Laser head travel system 5:

[0063] During the laser cladding process, as the tube rotates, the laser head 1 runs stably at a certain speed in the axial direction (relative to the axial direction of the tube being clad by the inner wall) inside the tube;

[0064] The present application uses a numerical control-servo motor-ball screw feed system to ensure that the laser head travel system 5 composed of an extension rod-bracket supporting the laser head 1 with a certain rigidity runs at a uniform and stable speed on the machine tool table.

[0065] Composition of laser head travel system 5:

[0066] (1) An extension rod with a certain rigidity, the length of which depends on the depth of cladding in the pipe;

[0067] (2) Laser head support device: A laser head support device is installed at one end of the extension rod to ensure that the distance H between the nozzle end of the laser head 1 and the inner wall of the pipe is stable. To this end, the present application designs a double roller laser head support device for laser cladding of the inner wall 8 of the pipe based on the inner wall 8 of the pipe (see attached Figure 2 ).

[0068] 5) The distance H from the end of the laser head 1 nozzle 11 to the inner wall of the pipe (see attached Figure 2 ):

[0069] In order to ensure that the alloy powder sent from the nozzle 11 of the laser head 1 can be well fused and well fused with the substrate, the distance H from the end of the nozzle of the laser head 1 to the inner wall of the pipe is an important parameter. Based on the laser used, the structure of the laser head 1, the laser cladding parameters and the powder feeding parameters, the distance H from the end of the nozzle of the laser head 1 to the inner wall of the pipe is set to 18mm±0.5mm.

[0070] 6) Workpiece rotation system 4: In order to perform laser cladding on the inner wall of the pipe, the pipe should be rotated at a stable speed to ensure the quality of laser cladding and the stable operation of the cladding process.

[0071] The energy density of the laser beam acting on the cladding part is a key factor in the quality of laser cladding. The relationship between the energy density E of the laser beam acting on the cladding part and the laser power P, the laser beam scanning speed V, and the spot size d is E ∽ P / Vd. In this application, the scanning speed of the laser beam can be controlled by adjusting the rotation speed of the steel pipe. Therefore, the stable rotation of the steel pipe at a specified speed is an important factor in ensuring the quality of laser cladding.

[0072] The present application uses a CNC-servo motor-precision screw transmission system to control the rotation speed of a steel pipe clamped by a four-jaw chuck, with an accuracy of 0.5° / s, to achieve stable control of the steel pipe rotation speed, thereby ensuring the stability of the laser beam scanning speed.

[0073] 7) Powder feeding system 3: This system is based on the characteristics of the alloy powder to be clad and the thickness requirements of the cladding layer, in combination with the laser cladding parameters (mainly laser power, laser beam diameter, spot size, laser scanning speed), and considering the powder deposition rate under given parameter conditions, to determine the powder feeding rate (unit time-grams of powder per minute: g / min), and the powder feeding parameters of the powder feeder. The alloy powder is stably delivered to the laser head 1 through the powder feeding pipeline with a stable argon flow (stable pressure and flow) to ensure a laser cladding layer of uniform thickness.

[0074] The powder feeding parameters of the powder feeding system 3 of the present application can be adjusted individually.

[0075] 8) Argon gas system 7: This system is used for: (1) argon gas purging and protection of the laser lens; (2) regulation, opening and closing of the powder feeding air flow pressure and flow rate of the powder feeding system 3; and (3) argon gas protection of the laser cladding molten pool.

[0076] 9) Cooling of laser head 1: Laser cladding is performed on the inner wall of the pipe. When continuous laser cladding is performed to a depth of 2m, the temperature of the outer wall of the oil pipe reaches 240°C. Cooling of laser head 1 becomes the key to ensure long-term stable operation of laser head 1.

[0077] The present application adds a cooling method combining a water cooling cover and air flow blowing to the laser head 1 .

[0078] The above systems are integrated into a sequential integrated control system, and the corresponding parameters of each system are input on the digital touch screen by computer to form a large-line long pipe inner wall laser cladding system controlled by the computer center. Then, it is combined with the cladding alloy to realize the rapid laser cladding of the corrosion-resistant alloy layer on the inner wall of the oil pipe and casing with a diameter greater than 300mm and a length of up to 12m.

[0079] Specific implementation principle:

[0080] In order to realize laser cladding on the entire inner wall of a 12m long oil casing, this application designs and constructs an integrated control production line for laser cladding of the inner wall of a long oil casing. The integrated control production line for laser cladding of the inner wall of the oil casing consists of the following parts: fiber laser 2, fiber + QBH interface, laser head 1, laser head travel system 5, workpiece rotation system 4, powder feeding system 3, argon supply system, water cooling control system, PLC combined computer control system (see attached Figure 1 )

[0081] Determination of laser cladding scheme for the entire inner wall of 12m long oil casing:

[0082] For the laser cladding of the inner wall of the oil pipe and casing with a length of 12m, the U-turn cladding method is adopted. That is, starting from one end of the pipe (defined as end A), cladding inwards to a depth of 1 / 2 of the entire pipe length (5.75m±0.25m, to position C); turning around, and then cladding inwards from the other end of the pipe (defined as end B) to position C, to achieve full-area laser cladding of the inner wall 8 of the pipe.

[0083] Coordinate definition: define the axial direction of the clad tubing or casing as the X direction;

[0084] On a plane perpendicular to the X direction, the up and down direction is the Z direction;

[0085] On a plane perpendicular to the X direction, the left and right direction is the Y direction.

[0086] The integrated CNC production line for laser cladding of the entire inner wall of a 12m long oil casing is composed of the following parts.

[0087] 1) This application selects to use a multi-mode continuous wave fiber laser 2 with an output power of 6 kW and a wavelength of 1080 nm.

[0088] 2) To ensure laser cladding of the inner wall 8 of the pipe at a depth of 5.75m±0.25m, this application is configured with a bed with a length of 10m, a width of 800mm, a height of 600mm, and a bed surface with guide rails for the bracket to walk stably;

[0089] 3) A laser head 1 extension rod bracket is configured, and the bracket can move stably at a certain speed on the bed through a CNC-servo motor-ball screw feed system.

[0090] 4) Extension rod: The extension rod is made of aluminum profile with model 8-800800A and material 6063-T5. The cross-sectional inertia of this profile is 84.45cm 3 . Make sure the extension rod has sufficient rigidity.

[0091] The length of the extension rod is 6m. The holes and grooves of the 8-800800A profile are used to place the laser optical fiber, powder delivery pipe, cooling water circuit pipe, and protective air pipe.

[0092] One end of the extension rod is fixedly mounted on the stand of the bracket, and the other end of the extension rod is mounted with a laser head supporting device.

[0093] 5) This application implements the use of a laser beam cohesion-reflection output coaxial powder feeding laser head 1, which has the following characteristics:

[0094] The laser output by the laser enters the laser head 1 through the optical fiber-QBH interface. The laser beam passes through the beam-straightening mirror-focusing mirror in the laser head 1 to the metal reflector. The laser beam is reflected at a certain angle and output from the laser head 1 through the protective lens.

[0095] In order to ensure the reflection efficiency and long service life of the reflection lens of the laser head 1, the surface roughness of the reflection lens should be less than 5nm.

[0096] 6) Determination of the distance H from the nozzle end of laser head 1 to the inner wall surface of the pipe to be clad:

[0097] This application takes into account the characteristics of rapid cladding, the structure of the laser head 1 and the powder feeding parameters of the laser cladding parameters, and sets the distance H from the nozzle end of the laser head 1 to the inner wall of the pipe to 18mm±0.5mm.

[0098] 7) Laser head support device: The laser head support device is of great significance for ensuring the stability of the distance H between the nozzle end of the laser head 1 and the inner wall surface of the pipe during the laser cladding process and the stable operation of the laser head 1 relative to the inner wall of the pipe.

[0099] For this purpose, the present application also constructs a double roller laser head support device based on the inner wall of the cladding workpiece (see attached Figure 2 ).

[0100] In the attached Figure 2 Middle: L: distance between two roller axes; RH: distance from the roller axis to the end of the nozzle of laser head 1;

[0101] H: The distance from the nozzle end of the laser head 1 to the cladding point on the inner wall 8 of the cladding pipe.

[0102] After the tube to be laser clad is determined (i.e. the inner diameter of the tube is determined), the diameter of the support roller 512 is selected (a ball bearing of a certain specification is used as the roller in this application), and the distance H from the nozzle end of the laser head 1 to the inner wall of the cladding tube is determined; the relevant dimensions of the laser head support device can be determined.

[0103] The setting of the laser head support device is intended to solve the problem that the produced and processed pipes are difficult to achieve a standard geometric circle. In the present application, since the extension rod is long and therefore easily deformed, the laser head 1 mainly relies on the support roller 512 to move along the inner wall 8 of the pipe, thereby achieving a self-centering effect.

[0104] 8) Workpiece rotation system 4:

[0105] In the present application, the workpiece rotating system 4 will ensure the laser scanning speed during laser inner hole cladding.

[0106] The present application uses a CNC-servo motor-precision screw transmission system to control the rotation speed of a steel pipe clamped by a four-jaw chuck. The system ensures that within the rotation speed range of 25° / s-55° / s, the rotation speed accuracy reaches 0.5° / s. This achieves stable control of the steel pipe rotation speed, thereby ensuring the stability of the laser beam scanning speed.

[0107] 9) Powder feeding system 3:

[0108] This application uses a 5L volume rotary disk quantitative-carrier gas delivery powder feeder. Powder is delivered to the laser head 1 through a powder delivery pipeline. The powder delivery carrier gas is argon.

[0109] 10) Water cooling system 6: ensure sufficient cooling of the laser, optical cable, and laser head 1. A water chiller is used for this purpose.

[0110] Cooling medium: pure water. Use a water chiller and equip it with corresponding pipelines to ensure the following cooling requirements:

[0111] For 6kW laser: cooling water temperature 24℃±1℃ water temperature, input pressure: 4-6Bar, flow rate: ≥52L / min;

[0112] For optical cables: cooling water temperature: 10-25°C, water inlet pressure: 4-6Bar, flow rate: 2L / min;

[0113] For laser head 1: Cooling water temperature: 10-25℃, water inlet pressure: 4-6Bar, flow rate: 8L / min

[0114] 11) Integrate all working systems, use PLC master control (see Figure 1), and use touch screen digital display to input and monitor the corresponding working parameters and display the cladding depth.

[0115] 12) Blowing heat removal inside the pipe: Use a cooling fan with a cooling capacity of 3.5kW and air at a delivery temperature of 10℃ to blow the inner hole of the pipe to achieve heat removal during the laser cladding process. It is beneficial to reduce the heat of the laser head 1 and to maintain the stability of the inner hole laser cladding process.

[0116] According to the corresponding laser cladding specifications, the inner wall of the 339.7 oil pipe and 473 casing can be clad in a thickness of 0.6mm-1.2mm, which has a good metallurgical bond with the steel pipe material matrix and meets the quality requirements.

[0117] 13) The integrated CNC production line for laser cladding of the entire inner wall of the oil casing is applied. When the laser scanning speed is within the range of 110mm / s-140mm / s, the corresponding axial feed speed of the laser head 1 is matched, the alloy powder that meets the requirements is used, and the corresponding powder feeding amount is matched, a corrosion-resistant alloy laser cladding layer with good metallurgical bonding with the pipe substrate, a cladding layer thickness of 0.6mm-1.2mm, and uniform surface morphology can be obtained, meeting various technical index requirements.

[0118] It should be noted that the terms used in this application are only for describing specific embodiments, rather than limiting the scope of this application. As shown in the specification of this application, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, the elements defined by the statement "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0119] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0120] The embodiments and / or implementation methods described above are only used to illustrate the preferred embodiments and / or implementation methods for realizing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any form. Any technical personnel in this field may make slight changes or modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as technologies or embodiments that are essentially the same as the present invention.

[0121] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. A 12m long oil casing inner wall full-area laser cladding system, characterized by: include: Laser (2), a multi-mode continuous wave laser with an output power of 6 kW and a wavelength of 1080 nm; The laser head (1) is a laser beam cohesion-reflection output coaxial powder feeding laser head (1), so that the laser beam with high energy density outputted from the nozzle of the laser head (1) mounted on the bracket (511) has a diameter change of ≤0.5 mm within a range of 15 mm to 25 mm from the nozzle end; A powder feeding system (3) is used to feed spherical nickel-based alloy powder having a melting point in the temperature range of 1300° C. to 1400° C. and a particle size of 53 μm to 150 μm to the laser head (1) and to laser-clad the powder on the inner wall of the pipe; A workpiece rotating system (4) is used to control the rotation speed of the pipe to be clad to be 25° / s-55° / s, with a rotation speed accuracy of 0.5° / s, thereby controlling the laser scanning speed; A laser head moving system (5) is used to control the laser head (1) to move axially inside the pipe; A water cooling system (6) for adequately cooling the laser (2), the optical cable, and the laser head (1); The laser head travel system (5) comprises an extension rod, the length of which is 6 m, one end of which is fixed to a support support on a machine tool table via a support, the other end of which is provided with a laser head support device for fixing the laser head (1), and the axial movement of the extension rod on which the laser head (1) is installed is controlled by a numerical control-servo motor-ball screw feed system; The laser head bracket (511) ensures that the distance between the nozzle end of the laser head (1) and the inner wall of the cladding pipe is H=f+fh during the laser cladding process, wherein f is the distance from the intersection point of the laser head (1) feeding powder to the nozzle end, and fh is the distance from the intersection point of the laser head (1) feeding powder to the inner wall surface of the cladding pipe, H=18mm±0.5mm, and fh=1.0mm-4.0mm; The laser head support device comprises a support (511) and support rollers (512), the laser head (1) being mounted on the support (511), and the support rollers (512) being mounted at both ends of the support (511); during the cladding process, as the clad pipe rotates, the support rollers (512) move along the inner wall of the pipe, thereby achieving 100 mm / s-150 mm / s scanning of the laser beam output from the laser head to achieve laser cladding, and H can be adjusted by adjusting the diameter of the support rollers (512) and the distance between the two support rollers (512).

2. The inner wall full-area laser cladding system of a 12m long oil casing as claimed in claim 1 is characterized in that: The powder delivery system (3) uses a 5L rotary disk quantitative-carrier gas delivery powder feeder, and delivers powder to the laser head (1) through a powder delivery pipeline, and the powder delivery carrier gas is argon.

3. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: The cooling medium of the water cooling system (6) is pure water, and the cooling parameters are as follows: For laser (2): cooling water temperature 24℃±1℃ water temperature, input pressure: 4-6Bar, Flow rate: ≥52L / min; For optical cables: cooling water temperature: 10-25°C, water inlet pressure: 4-6Bar, flow rate: 2L / min; For the laser head (1): cooling water temperature: 10-25°C, water inlet pressure: 4-6 Bar, flow rate: 8 L / min.

4. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: It also includes an argon system (7), which is used on the one hand to provide a powder delivery carrier gas, and on the other hand to perform argon purge protection on the output mirror in the laser beam cohesion-reflection output coaxial powder delivery laser head (1) before the laser head (1) is turned on.

5. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: It also includes a cold air blower, which is used to blow air with a cooling capacity of 3.5 kW and a delivery temperature of 10° C. into the inner hole of the pipe during the laser cladding process, so as to achieve heat dissipation by blowing air inside the pipe during the laser cladding process.

6. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: The surface roughness of the reflective lens in the laser beam internal focusing-reflection output coaxial powder feeding laser head (1) is less than 5 nm.

7. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: The extension rod is made of aluminum profile with a model material of 6063-T5.

8. The inner wall full-area laser cladding system of a 12m long oil casing according to claim 1 is characterized in that: The workpiece rotation system (4) comprises a numerically controlled machine tool, a screw transmission system arranged on the numerically controlled machine tool, and a servo motor for controlling the rotation of a screw of the screw transmission system.

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