High-performance laser additive alloy for surface of valve rod of high-temperature and high-pressure valve of power plant

Abstract

The invention relates to the technical field of alloys, and discloses a power plant high-temperature and high-pressure valve rod surface laser additive high-performance alloy which comprises the following components in parts by weight: 40-50 parts of Ni, 25-30 parts of Co, 20-25 parts of Cr, 6-10 parts of Mo, 2-5 parts of Al, 1-2 parts of Ti, 0.4-0.8 part of Y and 0.1-0.3 part of La. The high-performance alloy disclosed by the invention has relatively good corrosion resistance and wear resistance.

Description

Technical Field

[0001] The present invention relates to the field of alloy technology, and in particular to a high-performance alloy for laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem of a power plant. Background Art

[0002] High-temperature, high-pressure valves in power plants play a vital role in energy conversion and transmission. However, these valves are subjected to long-term exposure to harsh operating environments characterized by high temperatures, high pressures, and severe corrosion, placing extremely high demands on the performance of valve stem materials. Traditional valve stem materials often struggle to simultaneously meet these multiple performance requirements, including high strength, high-temperature resistance, and corrosion resistance. This leads to problems such as wear, corrosion, and deformation of the valve stem during use, impacting valve operation and reducing power plant efficiency and safety. Therefore, preventing this phenomenon is crucial to solving the problem. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In response to the deficiencies in the prior art, the present invention provides a high-performance alloy for laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant, which is wear-resistant and corrosion-resistant.

[0005] (2) Technical solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-performance alloy for laser additive manufacturing of the surface of a high-temperature and high-pressure valve stem in a power plant, comprising the following components by weight: 40-50 parts by weight of Ni, 25-30 parts by weight of Co, 20-25 parts by weight of Cr, 6-10 parts by weight of Mo, 2-5 parts by weight of Al, 1-2 parts by weight of Ti, 0.4-0.8 parts by weight of Y, and 0.1-0.3 parts by weight of La.

[0007] Further, the following steps are included:

[0008] Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum reactor according to the ratio of claim 1 for smelting, and hold the mixture for 40-60 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot;

[0009] Step 2: crushing and grinding the alloy ingot, using air flow milling to make it into powder, and screening;

[0010] Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface;

[0011] Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

[0012] Furthermore, the smelting temperature in step 1 is 1550-1600°C.

[0013] Furthermore, in the step 2, the powder particle size is controlled to be 45-80 μm.

[0014] Furthermore, the substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra1.1-1.6μm; the substrate surface is preheated at a temperature of 260-300°C for 40-55 minutes to reduce thermal stress during the laser additive process;

[0015] The preparation method of the rust remover is:

[0016] S1. Add 1.3-1.5 g of 1,4-phenylenediamine and 2.2-2.3 g of vanillin to acetone solvent, stir and mix, and react at 50-55 ° C for 3-6 hours. After the reaction is complete, wash and dry to obtain an intermediate;

[0017] S2. Add 1-2 g of the intermediate and 0.4-0.8 g of citric acid into a blender and stir for 10-15 min to obtain a rust remover.

[0018] Furthermore, in the step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 2400-3000W, the scanning speed is 7-10mm / s, and the spot diameter is 3-4mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating. The thickness of each layer is 0.3-0.5mm, and the deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 20-25L / min to prevent the alloy from oxidizing at high temperatures.

[0019] Furthermore, after the laser additive manufacturing in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 850-900°C, keeping warm for 2-4 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to a surface roughness of Ra0.4-0.8μm.

[0020] Furthermore, the valve stem of the high-temperature and high-pressure valve of the power plant is made of high-performance alloy.

[0021] (3) Beneficial technical effects

[0022] The high-performance alloy laser-additive-coated on the surface of the high-temperature, high-pressure valve stem in power plants exhibits high strength, wear resistance, and corrosion resistance, meeting the requirements for long-term, stable operation of high-temperature, high-pressure valve stems in complex, harsh environments. The alloy coating maintains excellent bonding strength with the stem substrate, preventing peeling or cracking during use, ensuring valve safety and reliability and extending the lifespan of the valve stem. The rust remover, containing a double Schiff base structure, effectively removes rust from the alloy surface, facilitating laser-additive-coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the H NMR spectrum of the intermediate. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] A high-performance alloy for laser additive manufacturing of the surface of high-temperature and high-pressure valve stems in power plants comprises the following components by weight: 40 parts by weight of Ni, 25 parts by weight of Co, 20 parts by weight of Cr, 6 parts by weight of Mo, 2 parts by weight of Al, 1 part by weight of Ti, 0.4 parts by weight of Y, and 0.1 parts by weight of La.

[0028] A method for preparing a high-performance alloy by laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant comprises the following steps:

[0029] Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum reactor according to the ratio and smelt them at a temperature of 1550°C for 40 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot;

[0030] Step 2: crushing and grinding the alloy ingot, and using air flow milling to make it into powder, the powder particle size is controlled at 45 μm, and sieving;

[0031] Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface;

[0032] Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

[0033] The substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra1.1μm; the substrate surface is preheated at a temperature of 260°C and a preheating time of 40 minutes to reduce thermal stress during the laser additive process;

[0034] The preparation method of the rust remover is:

[0035] S1. Add 1.3 g of 1,4-phenylenediamine and 2.2 g of vanillin to acetone solvent, stir and mix, and react at 50°C for 3 h. After the reaction is complete, wash and dry to obtain an intermediate;

[0036] S2. Add 1 g of the intermediate and 0.4 g of citric acid into a blender and stir for 10 min to obtain a rust remover.

[0037] In step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 2400W, the scanning speed is 7mm / s, and the spot diameter is 3mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating. The thickness of each layer is 0.3mm, and the deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 20L / min to prevent the alloy from oxidizing at high temperatures.

[0038] After the laser additive manufacturing process in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 850°C, keeping the temperature for 2 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to achieve a surface roughness of Ra0.4μm.

[0039] Example 2

[0040] A high-performance alloy for laser additive manufacturing of the surface of high-temperature and high-pressure valve stems in power plants comprises the following components by weight: 50 parts by weight of Ni, 30 parts by weight of Co, 25 parts by weight of Cr, 10 parts by weight of Mo, 5 parts by weight of Al, 2 parts by weight of Ti, 0.8 parts by weight of Y, and 0.3 parts by weight of La.

[0041] A method for preparing a high-performance alloy by laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant comprises the following steps:

[0042] Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum reactor according to the ratio and smelt them at a temperature of 1600°C for 60 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot;

[0043] Step 2: crushing and grinding the alloy ingot, and using air flow milling to make it into powder, the powder particle size is controlled at 80 μm, and sieving;

[0044] Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface;

[0045] Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

[0046] The substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra 1.6 μm; the substrate surface is preheated at a temperature of 300° C. and a preheating time of 55 minutes to reduce thermal stress during the laser additive process;

[0047] The preparation method of the rust remover is:

[0048] S1. Add 1.5 g of 1,4-phenylenediamine and 2.3 g of vanillin to acetone solvent, stir and mix, and react at 55°C for 6 h. After the reaction is complete, wash and dry to obtain an intermediate;

[0049] S2. Add 2 g of the intermediate and 0.8 g of citric acid into a blender and stir for 15 min to obtain a rust remover.

[0050] In the step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 3000W, the scanning speed is 10mm / s, and the spot diameter is 4mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating. The thickness of each layer is 0.5mm, and the deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 25L / min to prevent the alloy from oxidizing at high temperatures.

[0051] After the laser additive manufacturing process in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 900°C, keeping the temperature for 4 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to achieve a surface roughness of Ra0.8μm.

[0052] Example 3

[0053] A high-performance alloy for laser additive manufacturing of the surface of high-temperature and high-pressure valve stems in power plants comprises the following components by weight: 45 parts by weight of Ni, 27 parts by weight of Co, 22 parts by weight of Cr, 8 parts by weight of Mo, 4 parts by weight of Al, 2 parts by weight of Ti, 0.6 parts by weight of Y, and 0.2 parts by weight of La.

[0054] A method for preparing a high-performance alloy by laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant comprises the following steps:

[0055] Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum induction furnace according to the proportions for smelting at a temperature of 1570°C for 50 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot;

[0056] Step 2: crushing and grinding the alloy ingot, and using air flow milling to make it into powder, the powder particle size is controlled at 70 μm, and sieving;

[0057] Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface;

[0058] Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

[0059] The substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra1.4μm; the substrate surface is preheated at a temperature of 280°C for 46 minutes to reduce thermal stress during the laser additive process;

[0060] The preparation method of the rust remover is:

[0061] S1. Add 1.4 g of 1,4-phenylenediamine and 2.2 g of vanillin to acetone solvent, stir and mix, and react at 53°C for 5 h. After the reaction is complete, wash and dry to obtain an intermediate;

[0062] S2. Add 1.5 g of the intermediate and 0.6 g of citric acid into a blender and stir for 12 min to obtain a rust remover.

[0063] In step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 2600W, the scanning speed is 8mm / s, and the spot diameter is 4mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating. The thickness of each layer is 0.4mm, and the deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 22L / min to prevent the alloy from oxidizing at high temperatures.

[0064] After the laser additive manufacturing process in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 870°C, keeping the temperature for 3 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to achieve a surface roughness of Ra0.6μm.

[0065] Example 4

[0066] A high-performance alloy for laser additive manufacturing of the surface of high-temperature and high-pressure valve stems in power plants comprises the following components by weight: 40 parts by weight of Ni, 25 parts by weight of Co, 20 parts by weight of Cr, 6 parts by weight of Mo, 2 parts by weight of Al, 1 part by weight of Ti, 0.4 parts by weight of Y, and 0.1 parts by weight of La.

[0067] A method for preparing a high-performance alloy by laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant comprises the following steps:

[0068] Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum reactor according to the ratio and smelt them at a temperature of 1550°C for 40 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot;

[0069] Step 2: crushing and grinding the alloy ingot, and using air flow milling to make it into powder, the powder particle size is controlled at 80 μm, and sieving;

[0070] Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface;

[0071] Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

[0072] The substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra 1.6 μm; the substrate surface is preheated at a temperature of 300° C. and a preheating time of 55 minutes to reduce thermal stress during the laser additive process;

[0073] The preparation method of the rust remover is:

[0074] S1. Add 1.4 g of 1,4-phenylenediamine and 2.2 g of vanillin to acetone solvent, stir and mix, and react at 53°C for 5 h. After the reaction is complete, wash and dry to obtain an intermediate;

[0075] S2. Add 1.5 g of the intermediate and 0.6 g of citric acid into a blender and stir for 12 min to obtain a rust remover.

[0076] In step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 2600W, the scanning speed is 8mm / s, and the spot diameter is 4mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating. The thickness of each layer is 0.4mm, and the deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 22L / min to prevent the alloy from oxidizing at high temperatures.

[0077] After the laser additive manufacturing process in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 870°C, keeping the temperature for 3 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to achieve a surface roughness of Ra0.6μm.

[0078] Performance Testing

[0079] The alloys were tested after being passivated at a constant potential in seawater (3.5 wt.% NaCl solution).

[0080] Wear test: Anton Paar THT friction and wear tester was used for testing, with a loading force of 20N, a wear time of 100min, a wear speed of 15m / min, and a wear distance of 1500m.

[0081] Table 1: Corrosion and wear resistance tests.

[0082]

[0083] As can be seen from Table 1, the high-performance alloy laser-added on the surface of the valve stem of the high-temperature and high-pressure valve in the power plant of the present invention has good corrosion resistance and wear resistance.

[0084] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

[0086] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.

Claims

1. A high-performance alloy for laser additive manufacturing of the surface of a high-temperature and high-pressure valve stem in a power plant, characterized in that: The invention comprises the following components by weight: 40-50 parts by weight of Ni, 25-30 parts by weight of Co, 20-25 parts by weight of Cr, 6-10 parts by weight of Mo, 2-5 parts by weight of Al, 1-2 parts by weight of Ti, 0.4-0.8 parts by weight of Y, and 0.1-0.3 parts by weight of La.

2. A method for preparing high-performance alloy by laser additive on the surface of high-temperature and high-pressure valve stems in power plants, characterized in that: The following steps are involved: Step 1: Place Ni, Co, Cr, Mo, Al, Ti, Y, and La into a vacuum reactor according to the ratio of claim 1 for smelting, and hold the mixture for 40-60 minutes to fully melt and uniformly mix the raw materials to obtain an alloy ingot; Step 2: crushing and grinding the alloy ingot, using air flow milling to make it into powder, and screening; Step 3: After pre-treating the surface of the valve stem substrate, laser additive manufacturing is used to deposit alloy powder on the substrate surface; Step 4: Heat treatment and surface treatment of the coating after laser additive manufacturing.

3. The method for preparing high-performance alloy by laser additive manufacturing on the surface of high-temperature and high-pressure valve stems of power plants according to claim 2, characterized in that: The smelting temperature in step 1 is 1550-1600°C.

4. The method for preparing high-performance alloy by laser additive manufacturing on the surface of high-temperature and high-pressure valve stems of power plants according to claim 2, characterized in that: In the step 2, the powder particle size is controlled at 45-80 μm.

5. The method for preparing high-performance alloy by laser additive manufacturing on the surface of high-temperature and high-pressure valve stems of power plants according to claim 2, characterized in that: The substrate pretreatment process in step 3 is as follows: the surface of the high-temperature and high-pressure valve stem substrate of the power plant is cleaned with a rust remover, and a combination of sandpaper polishing and ultrasonic cleaning is used to ensure that the substrate surface roughness reaches Ra1.1-1.6μm; the substrate surface is preheated at a temperature of 260-300°C for 40-55 minutes to reduce thermal stress during the laser additive process; The preparation method of the rust remover is: S1. Add 1.3-1.5 g of 1,4-phenylenediamine and 2.2-2.3 g of vanillin to acetone solvent, stir and mix, and react at 50-55 ° C for 3-6 hours. After the reaction is complete, wash and dry to obtain an intermediate; S2. Add 1-2 g of the intermediate and 0.4-0.8 g of citric acid into a blender and stir for 10-15 min to obtain a rust remover.

6. The method for preparing high-performance alloy by laser additive manufacturing on the surface of high-temperature and high-pressure valve stems of power plants according to claim 2, characterized in that: In the step three, the laser additive process is as follows: a fiber laser is used as the laser source, the laser power is 2400-3000W, the scanning speed is 7-10mm / s, and the spot diameter is 3-4mm; the alloy powder is evenly transported to the laser action area through a coaxial powder feeding system, and is deposited layer by layer on the surface of the valve stem substrate to form a high-performance alloy coating, with each layer having a thickness of 0.3-0.5mm. The deposition operation is repeated according to the required coating thickness until the predetermined thickness is reached; during the laser additive process, argon is used as the protective gas, and the protective gas flow rate is 20-25L / min to prevent the alloy from oxidizing at high temperatures.

7. The method for preparing high-performance alloy by laser additive manufacturing on the surface of high-temperature and high-pressure valve stems of power plants according to claim 2, characterized in that: After the laser additive manufacturing process in step 4 is completed, the coating is heat treated. The heat treatment process is as follows: heating to 850-900°C, keeping the temperature for 2-4 hours, and then air cooling to room temperature. The heat treatment can eliminate the residual stress generated during the laser additive manufacturing process, further improve the density and bonding strength of the coating, and finally grind and polish the coating surface to achieve a surface roughness of Ra0.4-0.8μm.

8. A method for preparing a high-performance alloy by laser additive manufacturing on the surface of a high-temperature and high-pressure valve stem in a power plant using the method according to any one of claims 1 to 7, characterized in that: The valve stem of the high-temperature and high-pressure valve of the power plant is made of high-performance alloy.

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