Underwater laser cladding material and forming method based on laser-induced self-purification / molten pool fluidity control coupling

Abstract

Based on the underwater laser cladding material and forming method coupled with laser-induced self-purification / molten pool fluidity control, the present invention aims to solve the problems of poor fluidity or even inability to form the laser cladding layer of damaged underwater parts of ships in an underwater environment, inability to eliminate internal pores in a timely manner, and low laser energy utilization efficiency. The underwater laser cladding material of the present invention includes an underwater molten pool fluidity control functional layer and an underwater laser-induced self-purification functional layer, wherein the underwater molten pool fluidity control functional layer includes a metal-based high-entropy alloy material and a strong carbide / high-fluidity eutectic structure-forming element, and the underwater laser-induced self-purification functional layer includes CaF2, SiO2, Al2O3, ZnO, ZrO2, CeO2, a metal-based high-entropy alloy material, and a waterproof adhesive. The forming quality of the underwater wet laser cladding layer prepared by the present invention is significantly improved, the cladding layer is full and the penetration depth is greatly increased, and the corrosion resistance of the prepared underwater wet laser cladding layer is significantly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of material processing, and in particular relates to an underwater laser cladding material and a forming optimization method based on the coupling of laser-induced self-purification and molten pool fluidity regulation. Background Art

[0002] As marine engineering continues to advance into the deep seas and oceans, the complex and ever-changing marine environment places higher demands on the service stability of key marine engineering equipment, such as ships. Large, critical underwater facilities, such as offshore platforms, unmanned underwater vehicles, and submarine pipelines, are constantly exposed to extremely harsh marine environments, including waves, winds, currents, and storms. They are inevitably subject to damage from corrosion, wear, and seawater scouring, which seriously impacts their service life and safety and stability. Furthermore, the difficulty and high cost of returning unpowered ships, unmanned underwater vehicles, and large underwater structural components to shore for repairs have limited the implementation of rapid repair technologies for these equipment.

[0003] Underwater laser in-situ repair technology can provide fast and effective emergency repair guarantees for key damaged underwater parts of marine engineering equipment such as ships. Underwater laser in-situ repair technology can be divided into three types: dry, local dry, and wet. Among them, the implementation of dry underwater laser cladding technology is restricted by the need for professional drainage equipment and professionals, and is costly and inefficient. Compared with dry underwater laser cladding technology, local dry underwater laser cladding technology is more convenient and economical, but due to the influence of drainage quality, water cannot be completely discharged, which will have an adverse effect on the quality of underwater laser cladding forming. When the entire molten pool is completely exposed to water, a well-formed underwater repair layer cannot be obtained. Underwater wet laser cladding technology relies solely on the characteristics of the material itself and does not require additional drainage equipment. It has huge application potential and broad application prospects.

[0004] The presence of water complicates the underwater laser cladding process. When conducting underwater laser cladding, the influence of the water environment on the deposition process will have a serious impact on the entire deposition process. The underwater laser cladding process faces harsh repair conditions such as water layer intrusion, high hydrogen and oxygen levels, and energy loss, which seriously affect the quality of underwater laser cladding and the high-quality repair of marine engineering equipment. At the same time, the heat exchange process of underwater wet laser cladding is significantly different from that of an air environment, and the cooling rate underwater is several times faster than in an air environment. The laser-induced plasma generated during the underwater wet laser cladding process can also shield some of the laser energy. The convection of underwater heat exchange also causes greater laser energy loss. The underwater laser-induced plasma will shield the laser, significantly reducing the efficiency of laser energy transmission, which in turn leads to poor quality or even failure of underwater laser cladding forming. In summary, how to achieve the coordinated improvement of forming quality, laser energy absorption efficiency and service performance in the underwater wet laser cladding process through the perspective of underwater repair material design is a key and difficult problem that needs to be solved urgently. This has important practical significance for the development of underwater in-situ online repair technology for key damaged underwater components of marine engineering equipment such as ships. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of poor fluidity or even inability to form the laser cladding layer of damaged underwater parts of ships in water environment, the inability to eliminate internal pores in time, and low laser energy utilization efficiency, and to provide an underwater laser cladding material and forming optimization method based on the coupling of laser-induced self-purification / molten pool fluidity control.

[0006] The underwater laser cladding material based on the coupling of laser-induced self-purification and melt pool fluidity control includes an underwater melt pool fluidity control functional layer and an underwater laser-induced self-purification functional layer. The underwater laser-induced self-purification functional layer is located above the underwater melt pool fluidity control functional layer. The underwater melt pool fluidity control functional layer and the underwater laser-induced self-purification functional layer are formed by a laser cladding process.

[0007] The underwater molten pool fluidity control functional layer is a mixed powder formed by mixing 90% to 95% by mass of a (high-strength and tough) metal-based high-entropy alloy material and 5% to 10% of a strong carbide / high-fluidity eutectic structure-forming element. The mixed powder is coated on the ship base material through a waterproof adhesive; the strong carbide / high-fluidity eutectic structure-forming element is Nb, Ta or Zr.

[0008] The underwater laser-induced self-purification functional layer is formed by mixing 20% ​​to 25% of CaF2, 20% of CaO, 15% to 20% of SiO2, 5% to 15% of Al2O3, 5% to 10% of ZnO, 5% to 10% of ZrO2, 0.5% to 1.5% of CeO2, 5% to 15% of metal-based high-entropy alloy material and 3% to 5% of waterproof adhesive in mass fraction.

[0009] The forming method of underwater laser cladding materials based on the coupling of laser-induced self-purification and molten pool fluidity control of the present invention is implemented according to the following steps:

[0010] 1. Grind the underwater part of the ship to be repaired to obtain the polished base material;

[0011] 2. Add 90% to 95% (high strength and toughness) metal-based high-entropy alloy material and 5% to 10% strong carbide / high fluidity eutectic structure forming elements into a planetary ball mill according to mass fraction, then add a waterproof binder and mix evenly, and then apply it on the polished base material to obtain a base material with an underwater molten pool fluidity control functional layer;

[0012] 3. Mixing 20-25% CaF2, 20% CaO, 15-20% SiO2, 5-15% Al2O3, 5-10% ZnO, 5-10% ZrO2, 0.5-1.5% CeO2, 5-15% metal-based high-entropy alloy material and 3-5% waterproof binder in accordance with mass fractions, and then coating the mixture on the underwater molten pool fluidity control functional layer to obtain a base material with a composite functional layer;

[0013] Fourth, the base material with the composite functional layer is placed in the underwater repair chamber, and the laser power is controlled to 3600-4000W and the scanning speed is 6-8mm / s for wet laser cladding, thereby completing the repair and forming of the underwater laser cladding material;

[0014] The strong carbide / high fluidity eutectic structure forming element in step 2 is Nb single substance, Ta single substance or Zr single substance.

[0015] The high-strength and toughness metal-based high-entropy alloy material of the present invention is a spherical powder with a mesh size of 150 to 200.

[0016] The underwater laser induced self-purification of the present invention is achieved by thermally decomposing protective materials such as CaO-SiO2-Al2O3-ZnO-ZrO2 metal oxides, CaF2 metal fluorides and the like under strong laser irradiation in the form of molten salts, thereby generating local micro-air bags near the underwater laser molten pool to ensure forming space, and at the same time, by generating low-melting-point slag, greatly reducing the content of inclusions inside the underwater laser cladding layer, thereby purifying the molten pool; utilizing the CeO2 rare earth oxide in the underwater laser induced self-purification functional layer to purify the molten pool, further reducing the distribution and content of impurities inside the cladding layer; utilizing the ZnO alkaline metal oxide in the underwater laser induced self-purification functional layer to regulate the acidity and alkalinity of the underwater laser induced self-purification functional layer, thereby preventing defects such as pores in the underwater cladding layer caused by excessive acidity from affecting the forming quality. The fluidity control of underwater molten pool is achieved through the design of high entropy alloy eutectic structure. The strong carbide-forming elements Nb / Ta / Zr and the eutectic structure-forming elements have more negative mixing enthalpy, which makes it easier to generate eutectic structure with better fluidity to fix the carbon elements inside the molten pool, reduce the viscosity of the molten pool and improve the metallurgical reaction in the molten pool. The forming quality of the underwater wet laser cladding layer and the laser energy absorption efficiency of the underwater molten pool are regulated. The effective control of fluidity promotes the flow behavior of the underwater molten pool and can significantly improve the utilization of underwater laser energy and processing efficiency. The application of high entropy alloys in underwater environment can also have more flexible design to meet the various requirements of underwater environment for cladding layer forming and key performance, and has broad application prospects.

[0017] By optimizing the formation of underwater laser cladding materials using the present invention on underwater steel surfaces used in ships, the resulting underwater wet laser cladding layer significantly improves its formation quality, resulting in a fuller cladding layer and a significantly increased penetration depth, significantly enhancing the corrosion resistance of the resulting underwater wet laser cladding layer. This underwater wet laser cladding forming quality optimization method boasts high laser energy absorption efficiency, good cladding layer formation quality, ease of operation, and ease of underwater automated repair. It has great potential for underwater in-situ repair of damaged critical underwater components of marine engineering equipment, such as ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the underwater laser cladding material based on the coupling of laser-induced self-purification and molten pool fluidity control of the present invention;

[0019] Figure 2 This is a macroscopic morphology of the NiCrCoFe laser cladding layer in water environment without the pre-set layer for underwater laser-induced self-purification and molten pool fluidity control functions in Example 1;

[0020] Figure 3 This is a macroscopic morphology of the NiCrCoFe laser cladding layer in water environment without the pre-set layer for underwater molten pool fluidity control in Example 2;

[0021] Figure 4 This is a cross-sectional morphology of the NiCrCoFe laser cladding layer in an aqueous environment without the pre-set layer for underwater molten pool fluidity control in Example 2;

[0022] Figure 5 This is a macroscopic morphology of the NiCrCoFe laser cladding layer in an aqueous environment with a pre-set layer for underwater laser-induced self-purification and molten pool fluidity control functions in Example 3;

[0023] Figure 6 This is a cross-sectional morphology of the NiCrCoFe laser cladding layer in an aqueous environment with a pre-set layer for underwater laser-induced self-purification and molten pool fluidity control functions in Example 3. DETAILED DESCRIPTION

[0024] Specific embodiment 1: The underwater laser cladding material based on the coupling of laser-induced self-purification and molten pool fluidity control in this embodiment includes an underwater molten pool fluidity control functional layer and an underwater laser-induced self-purification functional layer. The underwater laser-induced self-purification functional layer is located above the underwater molten pool fluidity control functional layer. The underwater molten pool fluidity control functional layer and the underwater laser-induced self-purification functional layer are formed by a laser cladding process.

[0025] The underwater molten pool fluidity control functional layer is a mixed powder formed by mixing 90% to 95% by mass of a (high-strength and tough) metal-based high-entropy alloy material and 5% to 10% of a strong carbide / high-fluidity eutectic structure-forming element. The mixed powder is coated on the ship base material through a waterproof adhesive; the strong carbide / high-fluidity eutectic structure-forming element is Nb, Ta or Zr.

[0026] The underwater laser-induced self-purification functional layer is formed by mixing 20% ​​to 25% of CaF2, 20% of CaO, 15% to 20% of SiO2, 5% to 15% of Al2O3, 5% to 10% of ZnO, 5% to 10% of ZrO2, 0.5% to 1.5% of CeO2, 5% to 15% of metal-based high-entropy alloy material and 3% to 5% of waterproof adhesive in mass fraction.

[0027] High-entropy alloys for underwater applications have flexible design capabilities to meet diverse requirements for cladding layer formation and key performance in underwater environments. Metal-based high-entropy alloy materials have excellent high-temperature stability, which can reduce the generation of oxide inclusions. Forming quality and service performance can be guaranteed through phase regulation. Metal-based high-entropy alloy materials are combined with strong carbide / high-fluidity eutectic structure-forming elements to improve the flow behavior of the underwater molten pool.

[0028] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the thickness of the underwater molten pool fluidity regulation functional layer is 1.2-1.6 mm, and the thickness of the underwater laser induced self-purification functional layer is 0.1-0.2 mm.

[0029] Specific embodiment 3: The forming method of underwater laser cladding material based on the coupling of laser-induced self-purification and molten pool fluidity control in this embodiment is implemented according to the following steps:

[0030] 1. Grind the underwater part of the ship to be repaired to obtain the polished base material;

[0031] 2. Add 90% to 95% (high strength and toughness) metal-based high-entropy alloy material and 5% to 10% strong carbide / high fluidity eutectic structure forming elements into a planetary ball mill according to mass fraction, then add a waterproof binder and mix evenly, and then apply it on the polished base material to obtain a base material with an underwater molten pool fluidity control functional layer;

[0032] 3. Mixing 20-25% CaF2, 20% CaO, 15-20% SiO2, 5-15% Al2O3, 5-10% ZnO, 5-10% ZrO2, 0.5-1.5% CeO2, 5-15% metal-based high-entropy alloy material and 3-5% waterproof binder in accordance with mass fractions, and then coating the mixture on the underwater molten pool fluidity control functional layer to obtain a base material with a composite functional layer;

[0033] Fourth, the base material with the composite functional layer is placed in the underwater repair chamber, and the laser power is controlled to 3600-4000W and the scanning speed is 6-8mm / s for wet laser cladding, thereby completing the repair and forming of the underwater laser cladding material;

[0034] The strong carbide / high fluidity eutectic structure forming element in step 2 is Nb single substance, Ta single substance or Zr single substance.

[0035] Specific embodiment 4: This embodiment is different from specific embodiment 3 in that the metal-based high entropy alloy material described in step 2 and step 3 is a spherical powder of 150 mesh to 200 mesh.

[0036] Specific embodiment five: This embodiment differs from specific embodiment three or four in that the metal-based high entropy alloy material in step two and step three is NiCrCoFe high entropy alloy.

[0037] In the NiCrCoFe high entropy alloy of this embodiment, Ni / Cr / Co / Fe are arranged in an equiatomic ratio.

[0038] Specific embodiment six: The difference between this embodiment and any one of specific embodiments three to five is that in step two, 95% of the metal-based high entropy alloy material and 5% of the strong carbide / high fluidity eutectic structure forming elements are added to the planetary ball mill according to mass fraction.

[0039] Specific embodiment 7: This embodiment is different from any one of specific embodiments 3 to 6 in that the strong carbide / high fluidity eutectic structure forming element is single substance Nb.

[0040] Specific embodiment eight: The difference between this embodiment and any one of specific embodiments three to seven is that in step three, 25% CaF2, 20% CaO, 20% SiO2, 10% Al2O3, 5% ZnO, 5% ZrO2, 0.5% CeO2, 9.5% metal-based high entropy alloy material and 5% waterproof binder are mixed evenly according to mass fraction.

[0041] Specific embodiment 9: This embodiment differs from any one of specific embodiments 3 to 8 in that a high-power JPT fiber laser is used in step 4.

[0042] Specific embodiment ten: This embodiment differs from any one of specific embodiments three to nine in that in step four, the laser power is controlled to be 3600-3800 W and the scanning speed is 6-8 mm / s for wet laser cladding.

[0043] Example 1: The forming method of underwater laser cladding material in this embodiment is implemented according to the following steps:

[0044] 1. Take a 50mm×20mm×10mm (thick) steel plate for underwater use on ships, perform sandblasting and grinding to remove impurities, use 240-1500﹟ sandpaper to perform rough grinding to make the surface of the steel plate bright and clean, and use acetone solution ultrasonic cleaning for 30 minutes to obtain a polished base material with a rough surface and no oil stains;

[0045] 2. Mixing a high-strength and tough metal-based high-entropy alloy material NiCrCoFe and a waterproof binder uniformly and coating the mixture on the surface of the polished base material to obtain a base material with a high-entropy alloy layer;

[0046] 3. The base material with the high-entropy alloy layer is placed in the underwater repair chamber. The underwater laser cladding adopts a high-power JPT fiber laser with a laser core diameter of 200μm, a controlled processing power of 3600W, and a scanning speed of 6mm / s to complete the repair and forming of the underwater laser cladding material.

[0047] The surface macroscopic image of the underwater laser cladding layer obtained in this embodiment is as follows Figure 2As shown in the figure, it can be seen that there are a large number of pore defects on the surface of the underwater wet laser repair layer without the addition of the underwater laser induced self-purification functional layer and the underwater molten pool fluidity control functional layer, the forming quality of the repair layer is poor, and the repair forming is discontinuous.

[0048] Example 2: The forming method of underwater laser cladding material in this embodiment is implemented according to the following steps:

[0049] 1. Take a 50mm×20mm×10mm (thick) steel plate for underwater use on ships, perform sandblasting and grinding to remove impurities, use 240-1500﹟ sandpaper to perform rough grinding to make the surface of the steel plate bright and clean, and use acetone solution ultrasonic cleaning for 30 minutes to obtain a polished base material with a rough surface and no oil stains;

[0050] 2. Mixing a high-strength and tough metal-based high-entropy alloy material NiCrCoFe and a waterproof binder uniformly and coating the mixture on the surface of the polished base material to obtain a base material with a high-entropy alloy layer;

[0051] 3. Mixing 25% CaF2, 20% CaO, 15% SiO2, 5% Al2O3, 5% ZnO, 5% ZrO2, 0.5% CeO2, 9.5% of a metal-based high-entropy alloy material NiCrCoFe and 5% of a waterproof binder according to mass fractions, and then coating the mixture on the high-entropy alloy layer to obtain a base material with a composite functional layer;

[0052] Fourth, the base material with the composite functional layer is placed in the underwater repair chamber. The underwater laser cladding adopts a high-power JPT fiber laser with a laser core diameter of 200μm, a controlled laser power of 3600W, and a scanning speed of 6mm / s for wet laser cladding, thereby completing the repair and forming of the underwater laser cladding material.

[0053] The surface macroscopic image of the underwater laser cladding layer obtained in this embodiment is as follows Figure 3 As shown in the figure, the porosity defects of the underwater wet laser repair layer with the underwater laser induced self-purification functional layer are significantly reduced, and the forming quality is improved, but the melting depth is shallow, and the surface still has obvious defects such as unevenness, incompleteness, and biting.

[0054] Example 3: The forming method of underwater laser cladding materials based on the coupling of laser-induced self-purification and molten pool fluidity control in this embodiment is implemented according to the following steps:

[0055] 1. Take a 50mm×20mm×10mm (thick) steel plate for underwater use on ships, perform sandblasting and grinding to remove impurities, use 240-1500﹟ sandpaper to perform rough grinding to make the surface of the steel plate bright and clean, and use acetone solution ultrasonic cleaning for 30 minutes to obtain a polished base material with a rough surface and no oil stains;

[0056] Second, 95% of a high-strength and tough metal-based high-entropy alloy material NiCrCoFe and 5% of a strong carbide / high-fluidity eutectic structure-forming element Nb are mixed evenly with a waterproof binder according to mass fraction, and then coated on the surface of the polished substrate material to obtain a substrate material with an underwater molten pool fluidity control functional layer;

[0057] 3. Mix 25% CaF2, 20% CaO, 20% SiO2, 10% Al2O3, 5% ZnO, 5% ZrO2, 0.5% CeO2, 9.5% metal-based high-entropy alloy material NiCrCoFe and 5% waterproof binder according to mass fraction, and then apply it to the underwater molten pool fluidity control functional layer to obtain a base material with a composite functional layer;

[0058] Fourth, the base material with the composite functional layer is placed in the underwater repair chamber. The underwater laser cladding adopts a high-power JPT fiber laser with a laser core diameter of 200μm, a controlled laser power of 3600W, and a scanning speed of 6mm / s for wet laser cladding, thereby completing the repair and forming of the underwater laser cladding material.

[0059] The surface macroscopic image of the underwater laser cladding layer obtained in this embodiment is as follows Figure 5 and Figure 6 As shown in the figure, it can be seen that under the coupling effect of laser-induced self-purification / molten pool fluidity control, the underwater repair layer has no obvious defects such as undercuts and pores, the penetration depth is significantly increased, and the forming quality is excellent.

Claims

1. Underwater laser cladding material based on laser-induced self-purification / molten pool fluidity control coupling, characterized by The underwater laser cladding material includes an underwater molten pool fluidity regulating functional layer and an underwater laser induced self-purification functional layer, wherein the underwater laser induced self-purification functional layer is located above the underwater molten pool fluidity regulating functional layer, and the underwater molten pool fluidity regulating functional layer and the underwater laser induced self-purification functional layer are formed by a laser cladding process; The underwater molten pool fluidity control functional layer is a mixed powder formed by mixing 90% to 95% by mass of a metal-based high-entropy alloy material and 5% to 10% of a strong carbide / high-fluidity eutectic structure-forming element. The mixed powder is coated on the ship base material through a waterproof adhesive; the strong carbide / high-fluidity eutectic structure-forming element is Nb, Ta or Zr. The underwater laser-induced self-purification functional layer is composed of 20% to 25% by mass of CaF2, 20% by mass of CaO, 15% to 20% by mass of SiO2, 5% to 15% by mass of Al2O3, 5% to 10% by mass of ZnO, 5% to 10% by mass of ZrO2, 0.5% to 1.5% by mass of CeO2, 5% to 15% by mass of a metal-based high-entropy alloy material, and 3% to 5% by mass of a waterproof binder. The metal-based high entropy alloy material is NiCrCoFe high entropy alloy.

2. The underwater laser cladding material based on laser-induced self-purification / molten pool fluidity control coupling according to claim 1 is characterized in that The thickness of the underwater molten pool fluidity control functional layer is 1.2~1.6mm, and the thickness of the underwater laser induced self-purification functional layer is 0.1~0.2mm.

3. The forming method of underwater laser cladding materials based on the coupling of laser-induced self-purification and molten pool fluidity control is characterized in that The forming method is implemented according to the following steps:

1. Grind the underwater part of the ship to be repaired to obtain the polished base material; Second, 90% to 95% of a metal-based high-entropy alloy material and 5% to 10% of a strong carbide / high-fluidity eutectic structure-forming element are added to a planetary ball mill according to their mass fractions. A waterproof binder is then added and mixed evenly. The mixture is then coated on the polished substrate to obtain a substrate material with an underwater molten pool fluidity control functional layer.

3. According to the mass fraction, 20-25% of CaF2, 20% of CaO, 15-20% of SiO2, 5-15% of Al2O3, 5-10% of ZnO, 5-10% of ZrO2, 0.5-1.5% of CeO2, 5-15% of a metal-based high-entropy alloy material and 3-5% of a waterproof binder are uniformly mixed, and then coated on the underwater molten pool fluidity control functional layer to obtain a base material with a composite functional layer; Fourth, place the base material with the composite functional layer into the underwater repair chamber, control the laser power to 3600~4000W, and the scanning speed to 6~8mm / s for wet laser cladding, thereby completing the repair and forming of the underwater laser cladding material; The strong carbide / high fluidity eutectic structure forming element described in step 2 is Nb, Ta or Zr; the metal-based high entropy alloy material described in steps 2 and 3 is NiCrCoFe high entropy alloy.

4. The underwater laser cladding material forming method based on the coupling of laser-induced self-purification and molten pool fluidity control according to claim 3 is characterized in that The metal-based high entropy alloy material described in step 2 and step 3 is a spherical powder with a mesh size of 150 to 200.

5. The underwater laser cladding material forming method based on the coupling of laser-induced self-purification and molten pool fluidity control according to claim 3 is characterized in that In step 2, 95% of the metal-based high entropy alloy material and 5% of the strong carbide / high fluidity eutectic structure forming elements are added into the planetary ball mill according to the mass fraction.

6. The underwater laser cladding material forming method based on the coupling of laser-induced self-purification and molten pool fluidity control according to claim 3 is characterized in that The strong carbide / high fluidity eutectic structure forming element is Nb.

7. The underwater laser cladding material forming method based on laser-induced self-purification / molten pool fluidity control coupling according to claim 3 is characterized in that In step three, 25% CaF2, 20% CaO, 20% SiO2, 10% Al2O3, 5% ZnO, 5% ZrO2, 0.5% CeO2, 9.5% metal-based high entropy alloy material and 5% waterproof binder are mixed evenly according to mass fraction.

8. The underwater laser cladding material forming method based on the coupling of laser-induced self-purification and molten pool fluidity control according to claim 3 is characterized in that In step 4, a high-power JPT fiber laser is used.

9. The underwater laser cladding material forming method based on laser-induced self-purification / molten pool fluidity control coupling according to claim 3 is characterized in that In step 4, the laser power is controlled to 3600~3800W and the scanning speed is 6~8mm / s for wet laser cladding.

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