X80 pipeline steel arc additive-ultrasonic impact composite cladding coating and preparation method

Abstract

The application discloses an X80 pipeline steel electric arc additive-ultrasonic impact composite cladding coating and a preparation method thereof, and belongs to the technical field of protective coatings. The preparation method comprises the following steps: adopting CMT electric arc additive manufacturing to deposit X80 pipeline steel base material, and forming a homogenous cladding coating. In the CMT electric arc additive manufacturing process, trace oxygen is introduced, so that the trace oxygen reacts with Ni, Mn and Fe in the cladding welding wire to generate nanometer oxide particles which are dispersedly distributed, thereby realizing dispersion strengthening of the cladding coating and ensuring good compatibility of the cladding coating with the X80 pipeline steel base. Ultrasonic impact treatment is performed on the homogenous cladding coating to introduce a plastic deformation hardening layer on the surface of the homogenous cladding coating, thereby forming a composite cladding coating with the dual effects of nanometer grain and nanometer oxide particle dispersion strengthening, and the surface strength, hardness and wear resistance of the X80 pipeline steel can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of protective coating technology, and in particular to an arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel and its preparation method. Background Technology

[0002] X80 pipeline steel, as a high-strength low-alloy pipeline steel, is widely used in many important fields such as high-pressure oil and gas long-distance pipelines, offshore platforms, and large storage tanks due to its excellent mechanical strength, good welding performance, and resistance to atmospheric corrosion and oil and gas media corrosion. It has become a key manufacturing material for core load-bearing structures and transportation components in these fields.

[0003] In actual service, X80 pipeline steel components often face the combined effects of complex working conditions such as wear, impact, and corrosion (especially hydrogen-induced corrosion and sulfide stress corrosion). However, the inherent defects of low surface hardness and insufficient wear resistance make the components prone to wear, deformation, and even failure, which seriously shortens the service life of pipelines and equipment, increases the production and maintenance costs in fields such as oil and gas transportation and marine engineering, and greatly limits the further application of X80 pipeline steel in harsh working conditions with high wear resistance, high load, and strong corrosion.

[0004] Existing technologies primarily strengthen X80 pipeline steel by preparing high-temperature alloy or ceramic coatings on the surface. However, due to significant differences in material composition, these technologies suffer from issues such as mismatched coefficients of thermal expansion, low bonding strength, and susceptibility to detachment and cracking. Furthermore, differences in electrochemical properties with X80 pipeline steel can easily lead to galvanic corrosion, which in turn damages the corrosion resistance of the substrate itself. In addition, other strengthening technologies also have drawbacks such as limited strengthening effects, complex processes, or high production costs. Summary of the Invention

[0005] To address the problems of existing technologies, this invention provides an arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel and its preparation method.

[0006] On the one hand, a method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is provided, the method comprising:

[0007] S1: CMT arc additive manufacturing is used to deposit X80 pipeline steel substrate material to form a homogeneous cladding coating. During the CMT arc additive manufacturing process, trace oxygen is introduced, which reacts with Ni, Mn and Fe in the cladding wire to generate dispersed nano-oxide particles.

[0008] S2: The homogeneous cladding coating is subjected to ultrasonic impact treatment to introduce a plastic deformation hardening layer on the surface of the homogeneous cladding coating, forming a composite cladding coating with the dual functions of nanocrystal and nano-oxide particle dispersion reinforcement.

[0009] Furthermore, prior to S1, the process includes grinding, degreasing, and derusting the X80 pipeline steel substrate material.

[0010] Preferably, the degreasing treatment uses an alkaline degreasing agent, which is a sodium silicate-sodium carbonate composite alkaline degreasing agent, prepared by mass fraction of 10%-15% sodium silicate, 5%-8% sodium carbonate, 2%-3% nonionic surfactant and the balance deionized water. The degreasing temperature is 50-70℃ and the degreasing time is 10-30 minutes. After degreasing, it is rinsed clean with deionized water. The rust removal treatment uses a dilute hydrochloric acid solution, the rust removal temperature is room temperature and the rust removal time is 5-15 minutes.

[0011] Furthermore, the CMT arc additive manufacturing process parameters in S1 are as follows: the shielding gas is argon, the gas flow rate is 15-25L / min, the welding current is 80-180A, the arc voltage is 12-20V, the wire feed speed is 3-8m / min, the welding torch travel speed is 5-15mm / s, the interpass overlap rate is 30%-60%, and the interpass temperature is ≤150℃.

[0012] Furthermore, the trace oxygen in S1 is introduced by mixing oxygen into the protective gas, wherein the volume fraction of oxygen in the protective gas is 0.1%-1.0%. The nanoscale oxide particles have a particle size of 50-200 nm and are one or more mixtures of NiO, MnO, Fe3O4, and Fe2O3, and their mass fraction in the cladding coating is 0.5%-3.0%.

[0013] Furthermore, the diameter of the cladding wire is 1.0-1.2 mm, and its chemical composition by mass fraction is: Cr: ≤0.05%, Ni: 0.80%-1.20%, Mo: 0.02%-0.3%, Mn: 1.10%-1.60%, Ti: 0.02%-0.1%, Cu: 0.04%-0.15%, Si: ≤1.0%, C: ≤0.05%, P: ≤0.02%, S: ≤0.01%, with the balance being Fe.

[0014] Furthermore, the thickness of the homogeneous cladding coating after additive manufacturing is controlled between 0.5 and 1.5 mm.

[0015] Furthermore, in S2, the process parameters for ultrasonic impact treatment are as follows: ultrasonic impact power is 300W~800W, ultrasonic impact frequency is 20kHz, impact head diameter is 2-5mm, impact speed is 1-5mm / s, impact overlap rate is 20%-80%, impact spacing is 0.1-0.5mm, and the number of ultrasonic impacts is 1-3.

[0016] Furthermore, the thickness of the plastic deformation hardening layer is 500-600 μm, and the particle size of the nanocrystals is 20-100 nm.

[0017] Furthermore, it also includes a post-processing step: the composite cladding coating is polished to remove surface burrs and oxide layers, and then cleaned and dried at a temperature of 80°C for 5 minutes.

[0018] On the other hand, an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is provided, which is prepared by the aforementioned method for preparing the electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel.

[0019] The beneficial effects of the technical solution provided by the present invention are: (1) By using CMT arc additive manufacturing combined with the introduction of trace oxygen elements, nanoscale oxide particles are generated in a dispersed manner, thereby achieving dispersion strengthening of the cladding coating. At the same time, the good compatibility between the cladding coating and X80 pipeline steel is guaranteed, avoiding the problems of low bonding strength and easy detachment caused by heterogeneous cladding coatings. It will not cause galvanic corrosion and effectively preserves the excellent corrosion resistance of X80 pipeline steel itself.

[0020] (2) By introducing a plastic deformation hardening layer through ultrasonic impact treatment, a dual-strength composite cladding coating of "nanocrystalline grains + nano-oxide particles" is formed. Compared with single strengthening technology, it can significantly improve the surface strength, hardness and wear resistance of X80 pipeline steel, effectively solve the inherent defects of insufficient surface performance of X80 pipeline steel, and extend the service life of parts.

[0021] (3) The raw materials (X80 pipeline steel cladding welding wire, oxygen, argon, etc.) used in the preparation method of the present invention are easy to obtain and inexpensive, which reduces the cost of surface strengthening of X80 pipeline steel from both raw material and process dimensions, and is conducive to large-scale industrial promotion and application.

[0022] (4) The preparation process is highly compatible. The process parameters of CMT arc additive manufacturing and ultrasonic impact can be adjusted according to actual engineering needs, and the thickness and strengthening effect of the composite cladding coating can be flexibly controlled to adapt to the usage requirements of X80 pipeline steel parts under different working conditions. It has a wide range of applications. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0024] Figure 1These are microhardness data images of the X80 pipeline steel cladding coating surface provided by the present invention for Comparative Example 1 and Comparative Example 2.

[0025] Figure 2 This is a scanning electron microscope (SEM) image of the X80 pipeline steel cladding coating provided in Comparative Example 1 of this invention.

[0026] Figure 3 This is a scanning electron microscope (SEM) image of the X80 pipeline steel cladding coating provided in Comparative Example 2 of this invention.

[0027] Figure 4 This is a comparison diagram of the residual stress on the surface of the composite cladding coating of X80 pipeline steel after being subjected to different impact powers according to Embodiment 1 of the present invention.

[0028] Figure 5 This is a comparison diagram of the residual stress on the surface of the composite cladding coating of X80 pipeline steel after different impact cycles in Embodiment 2 of the present invention.

[0029] Figure 6 This is a comparison diagram of residual stress on the surface of the composite cladding coating of X80 pipeline steel after different impact overlap rates in Embodiment 3 of the present invention.

[0030] Figure 7 This is a comparison diagram of the residual stress on the surface of the X80 pipeline steel cladding coating of Comparative Example 3 and the composite cladding coating of X80 pipeline steel of Example 4 after different impacts provided by the present invention.

[0031] Figure 8 This is a comparison diagram of the tensile properties of the X80 pipeline steel cladding coating of Comparative Example 3 and the composite cladding coating of X80 pipeline steel of Example 4 after different impact cycles. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0034] Example 1:

[0035] An electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is prepared by the following steps:

[0036] Step (101): Select X80 pipeline steel cladding welding wire as the CMT arc additive manufacturing consumable. Its chemical composition (mass fraction) is as follows: Cr: ≤0.05%, Ni: 0.80%-1.20%, Mo: 0.02%-0.3%, Mn: 1.10%-1.60%, Ti: 0.02%-0.1%, Cu: 0.04%-0.15%, Si: ≤1.0%, C: ≤0.05%, P: ≤0.02%, S: ≤0.01%, with the balance being Fe. Place the welding wire in a vacuum drying oven and dry it at 80℃ for 2 hours to remove surface adsorbed moisture, then set it aside for use.

[0037] Step (102): Using X80 pipeline steel as the base material, cut it into 100mm×50mm×8mm samples, and then successively pass it through sandpaper grinding (from 80 grit to 1000 grit), acetone ultrasonic cleaning for 15min, degreasing treatment, rust removal treatment, deionized water rinsing 3 times, and hot air drying (80℃, 10min) to remove oxide scale, oil stains and impurities from the surface of the base material, and obtain a clean and uniformly rough CMT arc additive manufacturing base material for later use.

[0038] Step (103): Select analytical pure oxygen as the source of trace oxygen element introduction. After pressure reduction by pressure reducing valve and precise control by flow meter, mix with protective gas and set aside for use.

[0039] Step (104): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters and trace oxygen introduction parameters as follows: Argon is used as the basic protective gas, and trace oxygen is mixed with argon to form a composite protective gas, in which the volume percentage of oxygen is controlled at 0.1% (trace oxygen introduction amount), the total gas flow rate is 15L / min, the welding current is 80A, the arc voltage is 12V, the wire feed speed is 3m / min, the welding torch travel speed is 5mm / s, the interpass overlap rate is 30%, and the interpass temperature is ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the protective gas flow rate, current and voltage stability, and oxygen flow accuracy respectively, to confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage, arc interruption, or oxygen flow fluctuation. It is ready for use.

[0040] Step (105): Fix the pretreated X80 pipeline steel substrate from step (102) onto a special fixture, adjust the fixture height so that the surface of the X80 pipeline steel substrate is at a suitable working distance from the welding torch nozzle; start the oxygen supply system, adjust the flow meter to the set value, and after the oxygen flow rate stabilizes, start the CMT arc additive manufacturing equipment to begin the preparation of the homogeneous cladding coating of X80 pipeline steel and the introduction of trace oxygen elements, so that the trace oxygen reacts with Ni, Mn, and Fe in the cladding wire. During the additive manufacturing process, monitor the gas flow rate and electrical parameters in real time to ensure that the parameters are constant; after the additive manufacturing is completed, first turn off the oxygen supply system, then turn off the CMT arc additive manufacturing equipment, and wait for the X80 pipeline steel substrate and homogeneous cladding coating to cool naturally to room temperature (25℃) to obtain an initial X80 pipeline steel homogeneous cladding coating sample containing trace oxygen and nano-oxide particles; it should be noted that the original X80 pipeline steel substrate does not contain oxides, and the nano-oxides are generated in the homogeneous cladding coating after CMT arc additive manufacturing.

[0041] Step (106): The homogeneous cladding coating sample with initial X80 pipeline steel is subjected to stress-relief annealing to eliminate residual stress generated during the CMT arc additive manufacturing process, stabilize the homogeneous cladding coating structure, and promote the uniform distribution of the generated nano-oxide particles. The surface of the homogeneous cladding coating is finely polished with 2000-grit sandpaper to remove surface burrs, protrusions, and loosely bonded particles. During the polishing process, deionized water is continuously rinsed to avoid scratches and secondary oxidation on the surface of the homogeneous cladding coating. After polishing, the sample is ultrasonically cleaned in acetone for 10 minutes to remove surface polishing dust and oil stains. It is then rinsed twice with deionized water and placed in a hot air drying oven at 80°C for 8 minutes to obtain the final X80 pipeline steel dispersion-reinforced homogeneous cladding coating sample. The thickness of the homogeneous cladding coating after additive manufacturing is controlled at 0.5 mm. The cladding coating contains dispersed nanoscale oxide particles with a particle size of 50-200 nm.

[0042] Step (107): Select 3 samples of the X80 pipeline steel dispersion-strengthened homogeneous cladding coating, and mark them as 1-1, 1-2 and 1-3 respectively. Clean all 3 samples with acetone ultrasonic for 5 min, rinse twice with deionized water, and dry at 80℃ for 5 min to remove surface impurities and moisture, and set aside for use.

[0043] Step (108): Fix the homogeneous cladding coating sample marked 1-1 onto the special fixture of the ultrasonic impact device. Adjust the position of the fixture so that the impact head is aligned with the center area of ​​the homogeneous cladding coating surface, ensuring that the impact head is perpendicularly attached to the homogeneous cladding coating surface. Debug the ultrasonic impact device and set the basic ultrasonic impact process parameters: ultrasonic impact power of 300W, ultrasonic impact frequency of 20kHz, impact head diameter of 2mm, contact pressure between the impact head and the homogeneous cladding coating surface of 1-1 of 0.3MPa, impact velocity of 1mm / s, single impact time of 10s, number of impacts of 1, impact overlap rate of 20%, and impact spacing of 0.1mm. After impact, allow the sample to cool naturally to room temperature. During the ultrasonic impact process (25℃), the impact area was continuously cooled with deionized water to prevent local overheating of the homogeneous cladding coating, which could lead to oxidation, cracking, and other defects. After the impact, a plastic deformation hardening layer (500μm thick) was introduced onto the surface of the homogeneous cladding coating, forming a composite cladding coating with the dual effects of nanocrystalline grains (20nm-100nm) and nano-oxide particle dispersion reinforcement. The equipment was then shut off, the sample was removed, and polished to remove surface burrs and oxide layers. It was then ultrasonically cleaned with acetone for 5 minutes to remove dust and impurities, rinsed twice with deionized water, and dried at 80℃ for 5 minutes to obtain the ultrasonically impacted composite cladding coating 1-1, ready for use. Simultaneously, polishing fluid (Al2O3) was used to polish the cross-section of the cladding coating, with alternating polishing of the transverse and longitudinal directions of the cross-section.

[0044] Step (109): Following the same fixture adjustment method and operation steps as described above, fix the homogeneous cladding coatings marked 1-2 and 1-3 respectively, and adjust the ultrasonic impact power to 600W and 800W respectively, while keeping the other ultrasonic impact process parameters unchanged. Complete the ultrasonic impact treatment and subsequent polishing, cleaning and drying treatment in sequence to obtain the composite cladding coating samples 1-2 and 1-3 after ultrasonic impact treatment, which are ready for use.

[0045] Example 2:

[0046] An electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is prepared by the following steps:

[0047] Steps (201) to (203) are the same as steps (101) to (103) in Example 1.

[0048] Step (204): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters and trace oxygen introduction parameters as follows: Argon is used as the basic protective gas, and trace oxygen is mixed with argon to form a composite protective gas, in which the volume percentage of oxygen is controlled at 0.5% (trace oxygen introduction amount), the total gas flow rate is 20L / min, the welding current is 120A, the arc voltage is 15V, the wire feed speed is 5m / min, the welding torch travel speed is 10mm / s, the interpass overlap rate is 50%, and the interpass temperature is ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the protective gas flow rate, current and voltage stability, and oxygen flow accuracy respectively, to confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage, arc interruption, or oxygen flow fluctuation. It is ready for use.

[0049] Step (205): Same as step (105) in Example 1.

[0050] Step (206): Same as step (106) in Example 1. The thickness of the homogeneous cladding coating after additive manufacturing is controlled at 1 mm.

[0051] Step (207): Select 3 samples of the X80 pipeline steel dispersion-strengthened homogeneous cladding coating, and mark them as 2-1, 2-2 and 2-3 respectively. Clean all 3 samples with acetone ultrasonic for 5 min, rinse twice with deionized water, and dry at 80℃ for 5 min to remove surface impurities and moisture, and set them aside for use.

[0052] Step (208): Fix the homogeneous cladding coating sample marked 2-1 onto the special fixture of the ultrasonic impact device, adjust the position of the fixture so that the impact head is aligned with the center area of ​​the homogeneous cladding coating surface, ensuring that the impact head is perpendicularly attached to the homogeneous cladding coating surface, debug the ultrasonic impact device, and set the basic ultrasonic impact process parameters: ultrasonic impact power is 600W, ultrasonic impact frequency is 20kHz, impact head diameter is 4mm, contact pressure between the impact head and the homogeneous cladding coating surface of 2-1 is 0.3MPa, impact speed is 3mm / s, single impact time is 10s, number of impacts is 1, impact overlap rate is 50%, impact spacing is 0.3mm, and allow the sample to cool naturally to room temperature after impact. At 25℃, the impact area was continuously cooled with deionized water during the ultrasonic impact process to avoid local overheating of the homogeneous cladding coating, which could lead to defects such as oxidation and cracking. After the impact, a plastic deformation hardening layer (600μm thick) was introduced on the surface of the homogeneous cladding coating, making it a composite cladding coating with the dual effects of nanocrystals (20nm-100nm) and nano-oxide particles dispersion reinforcement. The equipment was turned off, the sample was taken out, polished to remove surface burrs and oxide layers, and then ultrasonically cleaned with acetone for 5 minutes to remove dust and impurities. It was rinsed twice with deionized water and dried at 80℃ for 5 minutes to obtain the composite cladding coating sample 2-1 after ultrasonic impact treatment, which was ready for use.

[0053] Step (209): Following the same fixture adjustment method and operation steps as described above, fix the samples marked 2-2 and 2-3, set the number of ultrasonic impacts to 2 and 3 respectively, with other parameters remaining the same, start the ultrasonic impact equipment, and complete the ultrasonic impact treatment with the set parameters; after the impact is completed, turn off the equipment, take out the samples, polish them, and ultrasonically clean them with acetone for 5 minutes to remove the dust and impurities generated during the impact process, rinse them twice with deionized water, and dry them at 80℃ for 5 minutes to obtain the composite cladding coating samples 2-2 and 2-3 after ultrasonic impact treatment, which are ready for use.

[0054] Example 3:

[0055] An electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is prepared by the following steps:

[0056] Steps (301) to (303) are the same as steps (101) to (103) in Example 1.

[0057] Step (304): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters and trace oxygen introduction parameters as follows: Argon is used as the basic protective gas, and trace oxygen is mixed with argon to form a composite protective gas, in which the volume percentage of oxygen is controlled at 1.0% (trace oxygen introduction amount), the total gas flow rate is 25L / min, the welding current is 180A, the arc voltage is 25V, the wire feed speed is 8m / min, the welding torch travel speed is 15mm / s, the interpass overlap rate is 60%, and the interpass temperature is ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the protective gas flow rate, current and voltage stability, and oxygen flow accuracy respectively, to confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage, arc interruption, or oxygen flow fluctuation. It is ready for use.

[0058] Step (305): Same as step (105) in Example 1.

[0059] Step (306): Same as step (106) in Example 1. The thickness of the homogeneous cladding coating after additive manufacturing is controlled at 1.5 mm.

[0060] Step (307): Select 4 samples of the X80 pipeline steel dispersion-reinforced homogeneous cladding coating, and mark them as 3-1, 3-2, 3-3 and 3-4 respectively. Clean all 4 samples with acetone ultrasonic for 5 min, rinse twice with deionized water, and dry at 80℃ for 5 min to remove surface impurities and moisture, and set aside for use.

[0061] Step (308): Fix the homogeneous cladding coating sample marked 3-1 onto the special fixture of the ultrasonic impact device, adjust the position of the fixture so that the impact head is aligned with the center area of ​​the homogeneous cladding coating surface, ensuring that the impact head is perpendicularly attached to the homogeneous cladding coating surface, debug the ultrasonic impact device, and set the basic ultrasonic impact process parameters: ultrasonic impact power is 800W, ultrasonic impact frequency is 20kHz, impact head diameter is 5mm, contact pressure between the impact head and the homogeneous cladding coating surface of 3-1 is 0.3MPa, impact speed is 5mm / s, single impact time is 10s, number of impacts is 1, impact overlap rate is 20%, impact spacing is 0.5mm, and allow the sample to cool naturally to room temperature (25℃) after impact. During the ultrasonic impact process, the impact area was continuously cooled with deionized water to prevent local overheating of the homogeneous cladding coating, which could lead to defects such as oxidation and cracking. After the impact, a plastic deformation hardening layer (600 μm thick) was introduced on the surface of the homogeneous cladding coating, forming a composite cladding coating with the dual effects of nanocrystal (20 nm-100 nm) and nano-oxide particle dispersion reinforcement. The equipment was turned off, the sample was taken out, polished to remove surface burrs and oxide layers, and then ultrasonically cleaned with acetone for 5 min to remove dust and impurities generated during the impact process. It was rinsed twice with deionized water and dried at 80 °C for 5 min to obtain the composite cladding coating sample 3-1 after ultrasonic impact treatment, which was ready for use.

[0062] Step (309): Following the same fixture adjustment method and operation steps as described above, fix the samples marked 3-2, 3-3, and 3-4, and adjust the ultrasonic impact overlap rate to 50%, 80%, and 95% respectively, while keeping the other ultrasonic impact process parameters unchanged. After the impact is completed, turn off the equipment, take out the samples, polish them, and ultrasonically clean them with acetone for 5 minutes to remove the dust and impurities generated during the impact process. Rinse them twice with deionized water and dry them at 80°C for 5 minutes to obtain the composite cladding coating samples 3-2, 3-3, and 3-4 after ultrasonic impact treatment, which are ready for use.

[0063] Example 4:

[0064] An electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel is prepared by the following steps:

[0065] Steps (401) to (403) are the same as steps (101) to (103) in Example 1.

[0066] Step (404): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters and trace oxygen introduction parameters as follows: Argon is used as the basic protective gas, and trace oxygen is mixed with argon to form a composite protective gas, in which the volume percentage of oxygen is controlled at 1.0% (trace oxygen introduction amount), the total gas flow rate is 20L / min, the welding current is 120A, the arc voltage is 16V, the wire feed speed is 5m / min, the welding torch travel speed is 8mm / s, the interpass overlap rate is 50%, and the interpass temperature is ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the protective gas flow rate, current and voltage stability, and oxygen flow accuracy respectively, to confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage, arc interruption, or oxygen flow fluctuation. It is ready for use.

[0067] Step (405): Same as step (105) in Example 1.

[0068] Step (406): Same as step (106) in Example 1.

[0069] Step (407): Select two samples of the X80 pipeline steel dispersion-reinforced homogeneous cladding coating, labeled as 4-1 and 4-2 respectively. Both samples are ultrasonically cleaned with acetone for 5 min, rinsed twice with deionized water, and dried at 80℃ for 5 min to remove surface impurities and moisture, and are ready for use.

[0070] Step (408): Fix the homogeneous cladding coating sample marked 4-1 onto the special fixture of the ultrasonic impact device. Adjust the position of the fixture so that the impact head is aligned with the center area of ​​the homogeneous cladding coating surface, ensuring that the impact head is perpendicularly attached to the homogeneous cladding coating surface. Debug the ultrasonic impact device and set the basic ultrasonic impact process parameters: ultrasonic impact power is 600W, ultrasonic impact frequency is 20kHz, impact head diameter is 5mm, contact pressure between the impact head and the homogeneous cladding coating surface of 4-1 is 0.3MPa, impact velocity is 5mm / s, and single impact time is 1 minute. The ultrasonic impact was performed for 0 seconds, with one impact cycle, an impact overlap rate of 50%, and an impact spacing of 0.5 mm. After impact, the sample was allowed to cool naturally to room temperature (25°C). During the ultrasonic impact, the impact area was continuously cooled with deionized water to prevent local overheating of the homogeneous cladding coating, which could lead to oxidation, cracks, and other defects. After the impact was completed, the equipment was turned off, the sample was removed, polished, and ultrasonically cleaned with acetone for 5 minutes to remove dust and impurities generated during the impact. The sample was then rinsed twice with deionized water and dried at 80°C for 5 minutes to obtain the ultrasonically impacted composite cladding coating sample 4-1, ready for use.

[0071] Step (409): Following the same fixture adjustment method and operation steps as described above, fix the sample marked 4-2, and impact it twice. Keep the other ultrasonic impact process parameters unchanged. After the impact is completed, turn off the equipment, take out the sample, polish it, and then ultrasonically clean it with acetone for 5 minutes to remove the dust and impurities generated during the impact. Rinse it twice with deionized water and dry it at 80°C for 5 minutes to obtain the composite cladding coating sample 4-2 after ultrasonic impact treatment, which is ready for use.

[0072] Comparative Example 1:

[0073] The preparation method for an X80 pipeline steel cladding coating without the introduction of trace oxygen and without ultrasonic impact includes the following steps:

[0074] Steps (501) and (502) are the same as steps (101) and (102) in Example 1.

[0075] Step (503): Debug the CMT arc additive manufacturing equipment, using only argon as the shielding gas (without introducing trace amounts of oxygen), with a total gas flow rate of 20L / min, welding current of 120A, arc voltage of 16V, wire feed speed of 5m / min, welding torch travel speed of 8mm / s, interpass overlap rate of 50%, and interpass temperature ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the shielding gas flow rate, current and voltage stability respectively, confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage or arc interruption, and then it is ready for use.

[0076] Step (504): Fix the pretreated X80 pipeline steel substrate on a special fixture, adjust the height of the fixture so that the surface of the X80 pipeline steel substrate is at a suitable working distance from the welding torch nozzle; start the CMT arc additive manufacturing equipment to begin the preparation of the X80 pipeline steel cladding coating (without introducing trace amounts of oxygen), monitor the process parameters in real time during the additive manufacturing process to ensure stability; after the additive manufacturing is completed, turn off the equipment and allow it to cool naturally to room temperature (25℃) to obtain the initial X80 pipeline steel cladding coating sample.

[0077] Step (505): Surface grinding and cleaning / drying treatment of the initial X80 pipeline steel cladding coating sample (without low-temperature oxidation post-treatment): Fine grinding of the cladding coating surface is performed using 2000-grit sandpaper to remove surface burrs, protrusions and loosely bonded powder particles. During the grinding process, deionized water is continuously rinsed to avoid scratches on the cladding coating surface. After grinding, the initial X80 pipeline steel cladding coating sample is ultrasonically cleaned in acetone for 10 minutes to remove surface grinding dust and oil stains. It is then rinsed twice with deionized water and placed in a hot air drying oven at 80°C for 8 minutes to obtain the final X80 pipeline steel cladding coating sample (without dispersed nanoscale oxide particles).

[0078] Step (506): Select one sample of the final X80 pipeline steel cladding coating, labeled Comparative Example 1-1. Clean it with acetone ultrasonically for 5 minutes, rinse twice with deionized water, and dry at 80℃ for 5 minutes to remove surface impurities and moisture. Do not perform any ultrasonic impact treatment; use it directly as the test sample for later use. The scanning transmission electron microscope image of Comparative Example 1-1 is shown below. Figure 2 As shown in the scanning electron microscope images, no oxide particles were observed. The distribution of the main trace elements is shown in Table 1 below, where Fe accounts for 95.32%, Ni accounts for 1.00%, Cr accounts for 0.45%, and Mo accounts for 0.55%.

[0079] Table 1. Microstructure of cladding coatings without oxygen introduction or ultrasonic impact.

[0080] C 0.18 Si 0.40 Mn 1.85 Cr 0.45 Ni 1.00 Mo 0.55 Cu 0.15 Ti 0.10 Fe 95.32 Total 100

[0081] Comparative Example 2:

[0082] The preparation method for an X80 pipeline steel cladding coating with trace amounts of oxygen but without ultrasonic impact includes the following steps:

[0083] Steps (601) to (603) are the same as steps (101) to (103) in Example 1.

[0084] Step (604): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters and trace oxygen introduction parameters as follows: Argon is used as the basic protective gas, and trace oxygen is mixed with argon to form a composite protective gas, in which the volume percentage of oxygen is controlled at 0.8% (trace oxygen introduction amount), the total gas flow rate is 20L / min, the welding current is 120A, the arc voltage is 16V, the wire feed speed is 5m / min, the welding torch travel speed is 8mm / s, the interpass overlap rate is 50%, and the interpass temperature is ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the protective gas flow rate, current and voltage stability, and oxygen flow accuracy respectively, to confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage, arc interruption, or oxygen flow fluctuation. It is ready for use.

[0085] Step (605): Fix the pretreated X80 pipeline steel substrate on a special fixture, adjust the fixture height so that the surface of the X80 pipeline steel substrate is at a suitable working distance from the welding torch nozzle; start the oxygen supply system, adjust the flow meter to the set value, and after the oxygen flow rate stabilizes, start the CMT arc additive manufacturing equipment to begin the preparation of the X80 pipeline steel cladding coating and the introduction of trace oxygen elements. Monitor the process parameters in real time during the additive manufacturing process to ensure stability; after the additive manufacturing is completed, first turn off the oxygen supply system, then turn off the main additive manufacturing equipment, and wait for it to cool naturally to room temperature (25℃) to obtain the initial X80 pipeline steel cladding coating sample containing trace oxygen and nano oxides.

[0086] Step (606): The initial X80 pipeline steel cladding coating sample obtained in step (605) is subjected to stress-relief annealing to eliminate residual stress generated by the CMT arc additive manufacturing process, stabilize the cladding coating structure, and promote the uniform distribution of the generated nano-oxide particles. The surface of the cladding coating is finely polished with 2000-grit sandpaper to remove surface burrs, protrusions, and unbonded molten droplets. During the polishing process, deionized water is continuously rinsed to avoid scratches and secondary oxidation on the surface of the cladding coating. After polishing, the sample is ultrasonically cleaned in acetone for 10 minutes to remove surface polishing dust and oil stains. It is then rinsed twice with deionized water and placed in a hot air drying oven at 80°C for 8 minutes to obtain the final X80 pipeline steel cladding coating (the cladding coating contains diffusely distributed nano-scale oxide particles).

[0087] One final X80 pipeline steel cladding coating sample was selected and labeled Comparative Example 2-1. It was ultrasonically cleaned with acetone for 5 min, rinsed twice with deionized water, and dried at 80℃ for 5 min to remove surface impurities and moisture. No ultrasonic impact treatment was performed, and it was directly used as the test sample for later use. The scanning transmission electron microscope image of Comparative Example 2-1 is shown below. Figure 3 As shown in the scanning electron microscope images, nano-oxide particles can be observed, and the distribution of their main trace elements is shown in Table 2 below.

[0088] Table 2 Oxide Energy Dispersive Spectroscopy Results

[0089] C 0.08 O 33.37 Mn 2.35 Cr 0.65 Ni 1.24 Mo 0.72 Cu 0.25 Ti 0.18 Fe 61.16 Total 100.00

[0090] Comparative Example 3:

[0091] The preparation method of an X80 pipeline steel cladding coating subjected to ultrasonic impact without introducing trace amounts of oxygen includes the following steps:

[0092] Steps (701) and (702) are the same as steps (101) and (102) in Example 1.

[0093] Step (703): Debug the CMT arc additive manufacturing equipment and set the core additive manufacturing process parameters as follows: use only argon as the shielding gas (without introducing trace amounts of oxygen), gas flow rate 20L / min, welding current 120A, arc voltage 16V, wire feed speed 5m / min, welding torch travel speed 8mm / s, interpass overlap rate 50%, interpass temperature ≤150℃; after the equipment is debugged, run it under no-load for 5 minutes, and check the shielding gas flow rate, current and voltage stability respectively, confirm that the welding torch moves smoothly and there are no abnormal phenomena such as gas leakage or arc interruption, and then it is ready for use.

[0094] Step (704): Fix the pretreated X80 pipeline steel substrate on a special fixture, adjust the height of the fixture so that the surface of the X80 pipeline steel substrate is at a suitable working distance from the welding torch nozzle; start the CMT arc additive manufacturing equipment to begin the preparation of the X80 pipeline steel cladding coating (without introducing trace amounts of oxygen), monitor the process parameters in real time during the additive manufacturing process to ensure stability; after the additive manufacturing is completed, turn off the equipment and allow it to cool naturally to room temperature (25°C) to obtain the initial X80 pipeline steel cladding coating sample (without dispersed nanoscale oxide particles).

[0095] Step (705): Surface grinding and cleaning and drying treatment of the initial X80 pipeline steel cladding coating sample (no low-temperature oxidation post-treatment): Fine grinding of the cladding coating surface is carried out with 2000-grit sandpaper to remove surface burrs, protrusions and unbonded powder particles. During the grinding process, deionized water is continuously rinsed to avoid scratches on the cladding coating surface. After grinding, the sample is ultrasonically cleaned in acetone for 10 minutes to remove surface grinding dust and oil stains. Then it is rinsed twice with deionized water and placed in a hot air drying oven at 80℃ for 8 minutes for later use.

[0096] Step (706): Select two initial X80 pipeline steel cladding coating samples after surface treatment, and mark them as Comparative Example 3-1 and Comparative Example 3-2. Clean them with acetone ultrasonically for 5 min, rinse them twice with deionized water, and dry them at 80℃ for 5 min to remove surface impurities and moisture. Set them aside for use.

[0097] Step (707): Fix the sample marked as Comparative Example 3-1 on the special fixture of the ultrasonic impact device, adjust the position of the fixture so that the impact head is aligned with the center area of ​​the cladding coating surface, and ensure that the impact head is perpendicular to the cladding coating surface. Start the ultrasonic impact device. Ultrasonic impact process parameters: ultrasonic impact frequency is 20kHz, impact head diameter is 5mm, contact pressure between impact head and cladding coating surface is 0.3MPa, impact speed is 5mm / s, single impact time is 10s, ultrasonic impact power is 600W, number of impacts is 1, impact overlap rate is 50%. After impact, allow it to cool naturally to room temperature (25℃). During ultrasonic impact, continuously cool the impact area with deionized water to avoid local overheating of the cladding coating and defects such as oxidation and cracks. After impact, turn off the device, take out the sample, ultrasonically clean it with acetone for 5min to remove dust and impurities generated during the impact, rinse it twice with deionized water, and dry it at 80℃ for 5min to obtain the final X80 pipeline steel cladding coating sample Comparative Example 3-1, ready for use.

[0098] Step (708): Following the same fixture adjustment method and operation steps as described above, fix the sample marked as Comparative Example 3-2, and impact it twice. Keep the other ultrasonic impact process parameters unchanged. After the impact is completed, turn off the equipment, take out the sample, and ultrasonically clean it with acetone for 5 minutes to remove the dust and impurities generated during the impact. Rinse it twice with deionized water and dry it at 80°C for 5 minutes to obtain the final X80 pipeline steel cladding coating sample Comparative Example 3-2, ready for use.

[0099] To systematically explore the comprehensive performance of the cladding coatings prepared in the above embodiments and comparative examples, clarify the influence of trace oxygen introduction and ultrasonic impact process parameters (power, number of times, overlap rate) on the performance of the cladding coatings, and verify the superiority of the preparation process of the present invention, a series of professional characterization methods will be used to comprehensively evaluate the performance of the cladding coating samples obtained in each embodiment and comparative example.

[0100] (1) The performance of CMT arc additive manufacturing process with or without the introduction of trace oxygen was evaluated. The final dispersion-strengthened cladding coating samples were characterized for performance, microstructure and oxides. The specific operation was as follows: Using a Vickers hardness tester, 20 measurement points were randomly selected on the surface of the final X80 pipeline steel cladding coating samples obtained in Comparative Example 1 and Comparative Example 2 to measure the hardness of the cladding coating. The results are as follows: Figure 1 As shown, the cladding coating with trace oxygen introduced in Comparative Example 2 (hardness 232 HV) showed a 16% increase in hardness compared to the cladding coating without trace oxygen introduced in Comparative Example 1 (hardness 200 HV). The microstructure of the cladding coating in Comparative Example 2 was observed using scanning electron microscopy (SEM), and the results are as follows. Figure 3 As shown, after introducing trace amounts of oxygen, micro- and nano-scale oxide particles are uniformly dispersed inside the cladding coating. The oxide particles are mainly Cr2, O3, NiO and Fe3O4, with an average particle size of 25 nm. There is no obvious agglomeration phenomenon, thus achieving the dispersion strengthening effect of the cladding coating.

[0101] (2) The influence of ultrasonic impact process parameters (power, number of times, overlap rate) on the performance of cladding coatings was investigated. Through a series of professional characterization methods, a comprehensive performance evaluation was conducted on the cladding coating samples obtained in each embodiment and comparative example. The specific characterization operations and evaluation results are as follows:

[0102] First, the residual stress of the composite cladding coating samples 1-1, 1-2, and 1-3 after ultrasonic impact treatment with different impact powers obtained in Example 1 was characterized. Using an X-ray diffractometer, 30 measurement points were selected on the surface and cross-section of the composite cladding coating (avoiding pores, oxide agglomeration regions, and interface transition zones). The diffraction angle range was set to 20°-80°, and the scanning speed was 2° / min. The sin²ψ method was used to determine the residual stress of the composite cladding coating, and the average residual stress at each point was calculated. The variation law of the residual stress of the cladding coating under different ultrasonic impact power parameters was compared. The results are as follows: Figure 4 As shown.

[0103] Figure 4 As can be seen, when the impact power increases from 400W to 600W, the impact energy is sufficient to drive sufficient plastic deformation in the surface of the homogeneous cladding coating, resulting in a significant increase in residual compressive stress. When the power is further increased from 600W to 800W, the plastic deformation of the surface of the homogeneous cladding coating reaches saturation. At this point, the yield strength of the material limits the further development of plastic deformation, and the additional impact energy cannot be converted into more residual compressive stress. Therefore, the residual compressive stress introduced by ultrasonic impact power of 600W and 800W is not significantly different, and their residual compressive stress curves tend to overlap. Although the residual compressive stress no longer increases significantly, the high-power impact of 800W brings additional negative effects, namely, the excessively high impact energy generates severe stress and strain gradients within the homogeneous cladding coating. This high strain rate cyclic loading easily induces microcrack initiation at defects (such as pores and inclusions) or grain boundaries within the homogeneous cladding coating. Intense plastic deformation and energy accumulation can disrupt the metallurgical bond or mechanical interlocking between the homogeneous cladding coating and the substrate, leading to microcracks at the interface and significantly reducing the toughness and bonding strength of the homogeneous cladding coating. Therefore, 600W is the preferred impact power for the homogeneous cladding coating surface.

[0104] Secondly, residual stress was characterized for the composite cladding coating samples 2-1, 2-2, and 2-3 after ultrasonic impact treatment with different impact numbers obtained in Example 2. The results are as follows: Figure 5 As shown.

[0105] from Figure 5 As can be seen, the residual compressive stress introduced on the surface of the homogeneous cladding coating after 3 impacts is the largest (-542MPa), but the excessive local stress introduced by it causes micro-cracks on the surface of the homogeneous cladding coating. Therefore, 2 impacts are the most effective.

[0106] Furthermore, residual stress was characterized in the ultrasonically impacted composite cladding coating samples 3-1, 3-2, 3-3, and 3-4 with different impact overlap rates obtained in Example 3. The results are as follows: Figure 6 As shown.

[0107] from Figure 6 As can be seen, the introduced residual compressive stress does not increase linearly with the increase of the overlap rate. The residual compressive stress introduced by the 50% overlap rate and the 95% overlap rate is not much different. Taking all factors into consideration, the 50% overlap rate is preferred.

[0108] In addition, residual stress was compared between the composite cladding coating samples 4-1 and 4-2 after ultrasonic impact treatment in Example 4, the final X80 pipeline steel cladding coating samples 3-1 and 3-2 obtained in Comparative Example 3, and the original samples. The results are as follows: Figure 7 As shown, Figure a is Comparative Example 3, and Figure b is Example 4.

[0109] from Figure 7 As can be seen, with an ultrasonic impact power of 600W and an overlap rate of 50% as the basic parameters, the hardness reaches its optimum when the number of impacts is 2. After introducing trace oxygen, the average hardness of the cladding coating can reach 285HV. Compared with the cladding coating without introducing trace oxygen but subjected to the same ultrasonic impact parameters (hardness 260HV), the hardness is increased by 9.6%. Compared with the cladding coating with only trace oxygen introduced but without ultrasonic impact (hardness 232HV), the hardness is increased by 22.8%.

[0110] Finally, the tensile properties of the composite cladding coating samples 4-1 and 4-2 after ultrasonic impact treatment in Example 4, the final X80 pipeline steel cladding coating samples 3-1 and 3-2 obtained in Comparative Example 3, and the original sample (X80 pipeline steel without any treatment) were compared. Tensile testing was performed using a tensile testing machine, and the average bond strength was calculated. The results are as follows: Figure 8 As shown, Figure a is Comparative Example 3, and Figure b is Example 4.

[0111] With an ultrasonic impact power of 600W and an overlap rate of 50% as the basic parameters, the surface mechanical properties of the cladding coating were optimal when the number of impacts was 2. The engineering stress and yield strength of the material were significantly improved after the introduction of oxygen, reaching 733.39MPa and 463.35MPa, respectively, which were 15.7% and 15.4% higher than those without the introduction of oxygen (633.23MPa and 401.38MPa), while the engineering strain of the material did not differ significantly.

[0112] In summary, ultrasonic impaction, as one of the core control methods of this invention, has a significant impact on the comprehensive performance of the composite cladding coating of X80 pipeline steel. Specifically, ultrasonic impaction can effectively reduce the internal porosity of the cladding coating through plastic deformation, improve the density and particle bonding strength of the cladding coating, and break the slight agglomeration of nano-oxide particles, promoting their uniform dispersion and distribution within the cladding coating. In turn, in conjunction with the introduction of trace oxygen and low-temperature oxidation post-treatment, it significantly improves the hardness, bonding strength and mechanical stability of the cladding coating.

[0113] The ultrasonic impact process, by controlling the macroscopic properties and microstructure of the cladding coating in multiple dimensions, works synergistically with the introduction of trace oxygen and low-temperature oxidation post-treatment to improve the overall performance of the X80 pipeline steel composite cladding coating. This further verifies the scientific nature and superiority of the preparation process of this invention, and clarifies the optimal control range of ultrasonic impact process parameters, providing reliable process guidance and characterization data support for the industrial preparation of cladding coatings.

[0114] It should be noted that the X80 pipeline steel arc additive manufacturing-ultrasonic impact composite cladding coating of this invention can be applied to X80 pipeline steel components in chemical equipment, marine engineering equipment, and nuclear power equipment. These components include structural parts and / or connectors, including pipes, valves, and / or flanges. The composite cladding coating can be used stably for a long time in harsh corrosive conditions such as temperatures ranging from -50℃ to 300℃ and media that are acidic, alkaline, or salt spray.

[0115] It is worth noting that this invention utilizes the synergistic effect of homogeneous CMT additive manufacturing and ultrasonic impaction. Specifically, CMT additive manufacturing technology is applied to the X80 pipeline steel substrate to clad a homogeneous X80 pipeline steel metal layer onto the substrate surface. During the CMT additive manufacturing process, argon is used as the working gas, and the welding wire is stably deposited at low heat input, rapidly depositing onto the substrate surface to form a dense homogeneous cladding coating. Simultaneously, the trace oxygen reaction during the additive manufacturing process promotes the formation of nanoscale oxide particles within the cladding coating, achieving initial dispersion strengthening of the cladding coating. Finally, the CMT additive cladding coating is subjected to ultrasonic impaction. The process involves impact treatment to introduce a plastic deformation hardening layer, which forms a nanocrystalline structure on the surface of the CMT additive manufacturing layer. Combined with the inherent density of the CMT additive manufacturing layer, this creates a composite cladding coating with dual reinforcement of "nanocrystalline grains + dense cladding coating". This composite cladding coating is firmly bonded to the X80 pipeline steel substrate, significantly improving the surface strength, hardness, and wear resistance of the X80 pipeline steel while retaining its excellent corrosion resistance. Moreover, the preparation process is simple, the raw materials are readily available, and the cost is low. It can be used stably for a long time under harsh conditions such as marine engineering, nuclear power equipment, and chemical plants, effectively solving many drawbacks of existing strengthening technologies.

[0116] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel, characterized in that, The method includes: S1: CMT arc additive manufacturing is used to deposit X80 pipeline steel substrate material to form a homogeneous cladding coating. During the CMT arc additive manufacturing process, oxygen is introduced, causing it to react with Ni, Mn, and Fe in the cladding wire to generate dispersed nano-oxide particles. The oxygen is introduced by mixing it into the shielding gas, with the oxygen volume fraction in the shielding gas being 0.1%-1.0%. S2: The homogeneous cladding coating is subjected to ultrasonic impact treatment to introduce a plastic deformation hardening layer on the surface of the homogeneous cladding coating, forming a composite cladding coating with nanocrystals and nano oxide particles. The process parameters for ultrasonic impact treatment are as follows: ultrasonic impact power is 300W~800W, ultrasonic impact frequency is 20kHz, impact head diameter is 2-5mm, impact speed is 1-5mm / s, impact overlap rate is 20%-80%, impact spacing is 0.1-0.5mm, and the number of ultrasonic impacts is 1-3.

2. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, Before S1, the process also includes grinding, degreasing, and derusting the X80 pipeline steel substrate material.

3. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, The CMT arc additive manufacturing process parameters in S1 are as follows: the shielding gas is argon, the gas flow rate is 15-25L / min, the welding current is 80-180A, the arc voltage is 12-20V, the wire feed speed is 3-8m / min, the welding torch travel speed is 5-15mm / s, the interpass overlap rate is 30%-60%, and the interpass temperature is ≤150℃.

4. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, The diameter of the cladding wire is 1.0-1.2 mm, and its chemical composition by mass fraction is: Cr: ≤0.05%, Ni: 0.80%-1.20%, Mo: 0.02%-0.3%, Mn: 1.10%-1.60%, Ti: 0.02%-0.1%, Cu: 0.04%-0.15%, Si: ≤1.0%, C: ≤0.05%, P: ≤0.02%, S: ≤0.01%, with the balance being Fe.

5. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, The thickness of the homogeneous cladding coating after additive manufacturing is controlled between 0.5 and 1.5 mm.

6. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, The thickness of the plastic deformation hardening layer is 500-600 μm, and the particle size of the nanocrystals is 20-100 nm.

7. The method for preparing an electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel according to claim 1, characterized in that, It also includes post-processing steps: polishing the composite cladding coating to remove surface burrs and oxide layers, followed by cleaning and drying at 80°C for 5 minutes.

8. An electric arc additive-ultrasonic impact composite cladding coating for X80 pipeline steel, characterized in that, The coating was prepared using the electric arc additive-ultrasonic impact composite cladding method for X80 pipeline steel according to any one of claims 1-7.

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