00Cr special alloy steel ultra-high-speed laser cladding process and application thereof

Abstract

This invention discloses an ultra-high-speed laser cladding process based on 00Cr special alloy steel, comprising the following steps: S1 heat treatment before cladding; S2 machining; S3 pretreatment of cladding powder; S4 ultra-high-speed laser cladding treatment; S5 fluorescent flaw detection; and S6 fine grinding. The coating dilution rate of the WC alloy cladding produced by this invention is less than 10%, resulting in stable process quality, high surface smoothness, and a post-cladding roughness of Ra2.5μm. It also features minimal machining allowance, uniform thickness, powder utilization exceeding 90%, and minimal material waste. Furthermore, the process cycle is short, leading to high production efficiency. After ultra-high-speed laser cladding, the 00Cr special alloy steel forms a complete and excellent metallurgical bond with the substrate, free from leaks, cracks, bubbles, or pores. It exhibits fine grains, high hardness, and excellent wear and corrosion resistance, significantly optimizing the performance of the oil pump plunger and making it suitable for long-term service in harsh oil well corrosive environments.

Description

Technical Field

[0001] This invention relates to an ultra-high-speed laser cladding process based on 00Cr special alloy steel and its application, specifically relating to B22F and the field of metal powder processing. Background Technology

[0002] Oil pumps are one of the three pumping devices in rod pump oil extraction systems in the petroleum industry. They experience significant wear and tear, and the pump plunger is a major wear component, its lifespan significantly limiting the pump's service life. The pump plunger suffers severe wear from fine sand particles in the oil-water mixture and is also subject to strong chemical corrosion, especially electrochemical corrosion. 00Cr special alloy steel possesses excellent mechanical and corrosion resistance properties and is widely used in the oil extraction industry. However, surface treatment is still required when manufacturing pump plungers to enhance their wear and corrosion resistance. Existing processing techniques are inefficient, and the adhesion between the plunger substrate and the surface coating is poor, leading to coating peeling over long-term use and shortening the plunger's service life. Therefore, developing a coating processing technology that enables pump plungers to meet both wear and corrosion resistance requirements is crucial.

[0003] Chinese invention patent CN202010898188.1 discloses a method for strengthening magnesium alloys using high-entropy alloy composite powder and ultra-high-speed laser cladding. This method involves melting the high-entropy alloy composite powder into droplets and dropping them into a molten pool on the surface of the magnesium alloy. Irradiation through the high-entropy alloy composite powder onto the magnesium alloy surface prevents over-melting of the magnesium alloy, resulting in a magnesium alloy with advantages such as low deformation and high surface smoothness. However, it is not suitable for cladding high-melting-point, high-wear-resistance substrates like 00Cr special alloy steel. Chinese invention patent CN202111463667.1 discloses a tungsten carbide-reinforced high-entropy alloy composite powder for ultra-high-speed laser cladding, its coating, preparation method, and application. The raw materials for the tungsten carbide-reinforced high-entropy alloy composite powder include tungsten carbide ceramic powder and high-entropy alloy powder, effectively avoiding the problem of coating cracking easily caused by tungsten carbide ceramic powder content exceeding 30wt% in existing technologies after ultra-high-speed laser cladding. It is suitable for surface protection of marine engineering equipment and mining machinery, but its corrosion inhibition effect is not significant in the oil extraction industry. Summary of the Invention

[0004] To improve the wear and corrosion resistance of oil pump plungers used in oil extraction, the first aspect of this invention provides an ultra-high-speed laser cladding process based on 00Cr special alloy steel, comprising the following steps:

[0005] S1 heat treatment before cladding;

[0006] S2 machining;

[0007] S3 cladding powder pretreatment;

[0008] S4 ultra-high-speed laser cladding process;

[0009] S5 fluorescent flaw detection;

[0010] S6 is obtained by fine grinding.

[0011] In a preferred embodiment, the heat treatment temperature in step S1 is 620-720℃, the holding time is 30-50min, and then the furnace is cooled to 250℃ before being removed from the furnace and air-cooled for annealing.

[0012] In a preferred embodiment, the specific steps of the cladding powder pretreatment in step S3 are as follows: place the cladding powder in a drying oven and dry it at a temperature of 60-130℃ for 30-60 minutes.

[0013] In a preferred embodiment, the cladding powder in step S3 is WC alloy powder or nickel-based alloy powder, wherein the particle size of the WC alloy powder is 25-80 μm and the mass fraction of WC alloy in the WC alloy powder is 20-30%.

[0014] In a preferred embodiment, the WC alloy powder is a mixture of nickel and WC alloy. More preferably, the WC alloy powder is a mixture of 75wt% Ni60A and 25wt% WC.

[0015] In a preferred embodiment, the ultra-high-speed laser cladding process in step S4 includes the following steps:

[0016] (1) Fix the cladding substrate; (2) Set the equipment parameters; (3) Align the laser cladding nozzle with the cladding substrate, with the cladding focal point 2-5mm away from the cladding substrate; (4) Start the ultra-high speed laser cladding process, and use the powder monitoring equipment to set the process parameters of the ultra-high speed laser cladding; (5) Start the remelting process.

[0017] As a preferred embodiment, the method for fixing the cladding substrate is as follows: the cladding substrate is clamped on a special machine tool for high-speed laser cladding, and then fixed by a hydraulic tailstock.

[0018] In a preferred embodiment, the cladding focal point is 3 mm away from the cladding substrate.

[0019] In a preferred embodiment, the device in step (2) includes a laser and a powder feeder, wherein the laser is selected from a disk laser, a fiber laser, or a diode laser.

[0020] In a preferred embodiment, the laser is a fiber laser.

[0021] In a preferred embodiment, the fiber laser has a laser power of 10-20kW, a laser wavelength of 900-950nm, and a laser spot diameter of 3-5mm. Preferably, the laser spot is circular, the laser power is 15kW, the laser spot diameter is 4mm, and the laser wavelength is 915nm.

[0022] In a preferred embodiment, the powder feeder is a synchronous powder feeder, and the powder feeder nozzle is a six-beam high-efficiency 3D powder feeding nozzle.

[0023] In a preferred embodiment, the powder feeder uses an inert gas with a pressure of 0.1-0.5 bar, a flow rate of 6-30 L / min, and a powder feeding rate of 5-80 g / min.

[0024] In a preferred embodiment, the powder feeder also includes a protective gas, wherein both the powder feeding gas and the protective gas are argon gases with a volume fraction greater than 99.9%.

[0025] The synchronous powder feeder uses a powder feeding gas with a pressure of 0.1-0.5 bar and a flow rate of 6-30 L / min, which can synchronously transport metal powder. The presence of argon gas can protect the coating from high-temperature oxidation.

[0026] As a preferred embodiment, the process parameters for ultra-high-speed laser cladding in step (4) are as follows: stepping speed of high-speed laser cladding machine tool: 1.0-5.0 mm / s; rotation speed: 100-500 r / min; cladding rate: 20-200 m / min; scanning line speed: 0.1-10 m / min; overlap rate: 50-90%; single-layer cladding thickness: 0.10-0.50 mm.

[0027] As a preferred embodiment, the process parameters for ultra-high-speed laser cladding in step (4) are as follows: stepping speed of high-speed laser cladding machine tool: 1.0-3.0 mm / s; rotation speed: 100-500 r / min; cladding rate: 20-100 m / min; scanning line speed: 0.1-3 m / min; overlap rate: 50-90%; single-layer cladding thickness: 0.10-0.50 mm.

[0028] During the experiment, the applicant discovered that laser cladding of WC alloy powder onto the surface of 00Cr special alloy steel, using a laser power of 10-20kW, resulted in a cladding layer with a thickness of 0.1-0.5mm. The resulting product can be used in plungers or polished rods of pump products. The likely reason is that both 00Cr special alloy steel and WC alloy powder have high melting points, requiring ultra-high-speed lasers to melt the WC alloy powder while it flows through the air. Simultaneously, the 00Cr special alloy steel substrate melts to form a molten pool, which, after bonding, rapidly cools to form a metallurgical coating. This coating is thin but not easily deformed, resulting in parts with high surface hardness without brittleness and good core toughness. This meets the requirements of strong chemical corrosion resistance, especially electrochemical corrosion, of the oil and water in oil pumps. Oil pump plungers also require a certain degree of toughness to meet wear and fatigue resistance requirements. If the laser power is below the preferred range, simultaneous melting of the substrate and powder cannot be achieved. If the power is above the preferred range, the coating thickness increases, leading to increased brittleness and decreased toughness, failing to meet the requirements of pump plungers.

[0029] In a preferred embodiment, the process parameters for remelting in step (5) are: scanning line speed of 0.5-5 m / min.

[0030] In a preferred embodiment, step S5 specifically involves: performing fluorescent flaw detection on the ultra-high-speed laser cladding layer using a fluorescent flaw detection device; if no microcracks are found, it is acceptable.

[0031] In a preferred embodiment, step S6 specifically involves: finely grinding the outer circle of the cladding substrate after ultra-high-speed laser cladding to obtain a coating that meets the technical requirements of the design drawings.

[0032] The second aspect of the present invention provides an application of ultra-high-speed laser cladding technology based on 00Cr special alloy steel, which is applied to the processing of oil pump plungers, water pump plungers, and oil sucker rods.

[0033] In a preferred embodiment, the cladding substrate is a pump plunger, and the outer diameter of the pump plunger machined in step S2 is [missing information].

[0034] In a preferred embodiment, the cladding substrate material is 00Cr special alloy steel, and the mass fraction of the elements in the 00Cr special alloy steel is as follows: C: ≤0.065%, Si: ≤0.35%, Mn: 0.80-1.20%, P: ≤0.035%, S: ≤0.010%, Cr: 9.00-12.50%, Ni: 0.60-1.00%, Mo: 0.15-0.90%, Cu: 0.30-0.60%, V: 0.05-0.15%, with Fe as the balance.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The ultra-high speed laser cladding process based on 00Cr special alloy steel described in this invention uses WC alloy powder to perform laser cladding on the surface of 00Cr special alloy steel. The metal powder and the substrate melt simultaneously, resulting in high production efficiency, short process cycle, low cost, good social and economic benefits, and great application potential.

[0037] (2) The ultra-high speed laser cladding process based on 00Cr special alloy steel described in this invention uses a laser power of 10-20kW to form a cladding layer with a thickness of 0.1-0.5mm. The resulting product can be applied to the plunger or polished rod of pump products and has good wear resistance and corrosion resistance.

[0038] (3) The ultra-high speed laser cladding process based on 00Cr special alloy steel described in this invention has a powder feeding gas pressure of 0.1-0.5 bar, a powder feeding gas flow rate of 6-30 L / min, and a powder feeding amount of 5-80 g / min. The conveyed powder can be uniformly bonded to the substrate and can protect the high-temperature coating from oxidation.

[0039] (4) The ultra-high speed laser cladding process based on 00Cr special alloy steel described in this invention, after ultra-high speed laser cladding, 00Cr special alloy steel forms a good metallurgical bond with the substrate, without leaks, cracks, bubbles or pores, with fine grains, high hardness, good wear resistance and corrosion resistance, which greatly optimizes the performance of the oil pump plunger and is suitable for long-term service in the harsh corrosion environment of oil wells.

[0040] (5) The ultra-high speed laser cladding process based on 00Cr special alloy steel described in this invention has a coating dilution rate of less than 10% for WC alloy cladding, stable process quality, high surface flatness, and a roughness of Ra2.5μm after cladding. It has a small processing allowance, uniform thickness, and is adjustable from 0.10 to 0.50mm. The powder utilization rate is greater than 90%, and there is little material waste. Moreover, the process cycle is short and the production efficiency is high. Attached Figure Description

[0041] Figure 1 Metallographic photograph of 00Cr special alloy steel after ultra-high speed laser cladding, Example 1;

[0042] Figure 2 Metallographic photograph of 00Cr special alloy steel after ultra-high-speed laser cladding, Example 2;

[0043] Figure 3 Metallographic photograph of 00Cr special alloy steel after ultra-high-speed laser cladding, Example 3;

[0044] Figure 4This is a metallographic photograph of 00Cr special alloy steel after ultra-high-speed laser cladding, as shown in Example 4.

[0045] Figure 5 This is a picture of the actual product after ultra-high speed laser cladding of 00Cr special alloy steel in Example 1.

[0046] Example 1

[0047] A high-speed laser cladding process based on 00Cr special alloy steel includes the following steps:

[0048] S1 heat treatment before cladding;

[0049] S2 machining;

[0050] S3 cladding powder pretreatment;

[0051] S4 ultra-high-speed laser cladding process;

[0052] S5 fluorescent flaw detection;

[0053] S6 is obtained by fine grinding.

[0054] The heat treatment temperature in step S1 is 670℃, the holding time is 40min, and then the furnace is cooled to 250℃ before being removed from the furnace and air-cooled for annealing.

[0055] The specific steps of the pretreatment of cladding powder in step S3 are as follows: place the cladding powder in a drying oven and dry it at a temperature of 90°C for 45 minutes.

[0056] The cladding powder in step S3 is WC alloy powder with a particle size of 45 μm. The WC alloy powder is a mixture of 75 wt% Ni60A and 25 wt% WC, and was purchased from Lingyun Welding Materials Factory in Nangong City.

[0057] The ultra-high-speed laser cladding process in step S4 includes the following steps:

[0058] (1) Fix the cladding substrate; (2) Set the equipment parameters; (3) Align the laser cladding nozzle with the cladding substrate, with the cladding focal point 3mm away from the cladding substrate; (4) Start the ultra-high speed laser cladding process and use the powder monitoring equipment to set the ultra-high speed laser cladding process parameters; (5) Start the remelting process.

[0059] The method for fixing the cladding substrate is as follows: the cladding substrate is clamped on a special machine tool for high-speed laser cladding, and then fixed by a hydraulic tailstock.

[0060] The equipment in step (2) includes a fiber laser and a synchronous powder feeder; the parameters of the fiber laser are shown in Table 1.

[0061] The powder feeder is a synchronous powder feeder, and the powder feeder nozzle is a six-beam high-efficiency 3D powder feeding nozzle.

[0062] The powder feeder contains a protective gas and an inert gas. Both the powder feeder and the protective gas are argon gases with a volume fraction greater than 99.9%. The parameters of the powder feeder are shown in Table 1.

[0063] The process parameters for ultra-high-speed laser cladding in step (4) are shown in Table 1.

[0064] The process parameters for the remelting process in step (5) are shown in Table 1.

[0065] The specific operation of step S5 is as follows: use a fluorescent flaw detection device to perform fluorescent flaw detection on the ultra-high speed laser cladding layer, and it is acceptable if no microcracks are found.

[0066] The specific operation of step S6 is as follows: the outer circle of the cladding substrate after ultra-high speed laser cladding is finely ground to obtain a coating that meets the technical requirements of the drawing design.

[0067] The cladding substrate is a pump plunger, and the outer diameter of the pump plunger machined in step S2 is [missing information].

[0068] The cladding substrate is 00Cr special alloy steel, and the mass fraction of elements in the 00Cr special alloy steel is as follows: C: ≤0.065%, Si: ≤0.35%, Mn: 0.80-1.20%, P: ≤0.035%, S: ≤0.010%, Cr: 9.00-12.50%, Ni: 0.60-1.00%, Mo: 0.15-0.90%, Cu: 0.30-0.60%, V: 0.05-0.15%, with Fe as the balance. The 00Cr special alloy steel material was purchased from Zhejiang Ruizhi Steel Industry Co., Ltd.

[0069] Example 2

[0070] A high-speed laser cladding process based on 00Cr special alloy steel is described. The specific steps are the same as in Example 1, and the different process parameters are shown in Table 1.

[0071] Example 3

[0072] A high-speed laser cladding process based on 00Cr special alloy steel is described. The specific steps are the same as in Example 1, and the different process parameters are shown in Table 1.

[0073] Example 4

[0074] A high-speed laser cladding process based on 00Cr special alloy steel is described. The specific steps are the same as in Example 1, and the different process parameters are shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] Performance testing

[0079] 1. Test the microscopic hardness of the ultra-high speed laser cladding coating according to the standard GB / T 4340.1-2009; use a fluorescent flaw detector to perform fluorescent flaw detection on the ultra-high speed laser cladding layer to observe whether there are microcracks.

[0080] 2. Cut the 00Cr special alloy steel after high-speed laser cladding perpendicular to the cladding direction and take a photograph with an optical microscope. The thickness of the cladding layer is H, the melting depth of the 00Cr special alloy steel substrate is h, and the dilution rate is [h / (h+H)]×100%.

[0081] The test results are shown in Table 2.

[0082] Table 2

[0083] Cladding layer thickness (mm) Microcracks Melting depth (mm) Dilution rate (%) Hardness (HV) Example 1 0.200 none 0.022 9.91 721 Example 2 0.185 none 0.016 7.96 766 Example 3 0.212 none 0.028 11.67 704 Example 4 0.413 none 0.102 19.81 620

[0084] Metallographic photographs of Examples 1-4 are shown below. Figure 1-4 The marked value is the thickness of the cladding layer.

[0085] Note: When taking metallographic photographs, differences may exist due to variations in the actual marking positions of the photographers, resulting in significant discrepancies in some values.

Claims

1. A high-speed laser cladding process based on 00Cr special alloy steel, characterized in that, Includes the following steps: S1 heat treatment before cladding; S2 machining; S3 cladding powder pretreatment; S4 ultra-high-speed laser cladding process; S5 fluorescent flaw detection; S6 can be obtained by fine grinding; The heat treatment temperature in step S1 is 620-720℃, the heat treatment holding time is 30-50min, and after the heat treatment in step S1, the furnace is cooled to 250℃ and then removed from the furnace for air cooling annealing. The cladding powder in step S3 is WC alloy powder, which is a mixture of 75wt% Ni60A and 25wt% WC, and the particle size of the WC alloy powder is 25-80μm. The process parameters for ultra-high-speed laser cladding in step S4 are as follows: stepping speed of the high-speed laser cladding machine tool: 1.0-5.0 mm / s; rotation speed: 100-500 r / min; cladding rate: 20-200 m / min. The scanning line speed is 0.1-10 m / min; the overlap rate is 50-90%; and the single-layer cladding thickness is 0.10-0.50 mm. The cladding substrate material is 00Cr special alloy steel, and the mass fraction of the elements in the 00Cr special alloy steel is as follows: C: ≤0.065%, Si: ≤0.35%, Mn: 0.80-1.20%, P: ≤0.035%, S: ≤0.010%, Cr: 9.00-12.50%, Ni: 0.60-1.00%, Mo: 0.15-0.90%, Cu: 0.30-0.60%, V: 0.05-0.15%, and Fe balance.

2. The ultra-high-speed laser cladding process based on 00Cr special alloy steel according to claim 1, characterized in that, The specific steps of the pretreatment of cladding powder in step S3 are as follows: place the cladding powder in a drying oven and dry it at a temperature of 60-130℃ for 30-60 minutes.

3. The ultra-high-speed laser cladding process based on 00Cr special alloy steel according to claim 1, characterized in that, The ultra-high-speed laser cladding process in step S4 includes the following steps: (1) Fix the cladding substrate; (2) Set the equipment parameters; (3) Align the laser cladding nozzle with the cladding substrate, and keep the cladding focal point 2-5 mm away from the cladding substrate; (4) Start the ultra-high speed laser cladding process and use the powder monitoring equipment to set the ultra-high speed laser cladding process parameters; (5) Start the remelting process.

4. The process for super high velocity laser cladding on 00Cr special alloy steel according to claim 3, characterized in that, The equipment in step (2) includes a laser and a powder feeder, wherein the laser is selected from one of a disk laser, a fiber laser, and a diode laser.

5. The process for super high velocity laser cladding on 00Cr special alloy steel according to claim 4, characterized in that, The fiber laser has a laser power of 10-20kW, a laser wavelength of 900-950nm, and a laser spot diameter of 3-5mm.

6. The ultra-high-speed laser cladding process based on 00Cr special alloy steel according to claim 4, characterized in that, The powder feeder includes a powder feeding gas, which is an inert gas with a pressure of 0.1-0.5 bar, a flow rate of 6-30 L / min, and a powder feeding amount of 5-80 g / min.

7. Use of the process according to any one of claims 1 to 6 for the superhigh-speed laser cladding of 00Cr special alloy steels, characterized in that, It is used in the machining of oil pump plungers, water pump plungers, and sucker rods.

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