Galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water and preparation method thereof

Abstract

The present invention belongs to the field of metal material corrosion, specifically a galvanic corrosion specimen and preparation method with strictly controlled area ratio in high temperature and high pressure water, which solves the problem that the commonly used galvanic corrosion specimen design is not applicable under high temperature and high pressure water conditions. The galvanic corrosion specimen includes a surfacing layer test plate, a cylindrical blind hole, a cylindrical specimen, a cap surfacing layer, and a circular hole. Its preparation process includes: blanking, surfacing I, machining I, flaw detection, drilling I, cylindrical machining, cleaning, assembly, surfacing II, heat treatment, cutting, drilling II, cleaning, packaging, etc. The present invention strictly controls the area ratio between different materials by controlling the aperture during drilling II. In the specimen preparation process, no other packaging materials except the test material are used, there is no risk of crevice corrosion, and the real position (space) relationship between materials in actual use can be strictly simulated. It is particularly suitable for related galvanic corrosion experiments in high temperature and high pressure water environments.

Description

Technical Field

[0001] The invention belongs to the field of metal material corrosion, and relates to the design and preparation technology of corrosion samples, and specifically to a galvanic corrosion sample with strictly controlled area ratio in high-temperature and high-pressure water and a preparation method thereof. Background Art

[0002] The inner surface of the SA-508grade 3 low alloy steel of the reactor pressure vessel of the pressurized water reactor nuclear power plant is welded with a 308L stainless steel lining to prevent the low alloy steel from being exposed to the primary water and corroding. During the operation of the nuclear power plant, bolts and other parts may fall off on the top of the pressure vessel. After a long period of friction and wear, the stainless steel lining on the surface of the low alloy steel may be worn through, exposing the corrosion-resistant low alloy steel to the primary water. Due to the large differences in composition and organization between low alloy steel and stainless steel, there will be a significant potential difference in the primary water, which makes it easy for galvanic corrosion to occur. Especially in the "large cathode and small anode" state, the low alloy steel will be severely corroded. However, the corrosion rate, possible corrosion development form and its impact on the operational reliability of the reactor pressure vessel are still unclear. In order to evaluate the galvanic corrosion tendency between the SA-508grade 3 low alloy steel and the 308L stainless steel cladding layer on the surface of the pressurized water reactor nuclear power plant reactor pressure vessel, it is necessary to evaluate the galvanic corrosion behavior of the SA-508grade 3 low alloy steel and the 308L stainless steel cladding layer in a simulated actual service environment. However, the traditional galvanic corrosion packaging method can neither withstand the high temperature and high pressure (350°C, 15.5MPa) primary circuit water environment, nor reflect the spatial position relationship between the low alloy steel and stainless steel cladding layers.

[0003] Therefore, it is necessary to obtain a method for preparing galvanic corrosion samples that can be used in a high-temperature and high-pressure (350°C, 15.5MPa) primary-loop water environment and strictly control the area ratio, so as to accurately study the galvanic corrosion behavior in high-temperature and high-pressure water, which is of great significance for the safe design, operation and management of nuclear power plants. Summary of the invention

[0004] The purpose of the present invention is to provide a galvanic corrosion specimen and a preparation method with strictly controlled area ratio in high-temperature and high-pressure water, so as to solve the problem that the traditional galvanic corrosion packaging method can neither withstand the high-temperature and high-pressure (350°C, 15.5MPa) primary circuit water environment nor reflect the spatial position relationship between the low-alloy steel and the stainless steel cladding layer, thereby improving the accuracy and repeatability of the experiment.

[0005] The technical solution of the present invention is as follows:

[0006] A galvanic corrosion specimen with strictly controlled area ratio in high-temperature and high-pressure water, the galvanic corrosion specimen comprising a surfacing test plate, a cylindrical blind hole, a cylindrical specimen, a cover surfacing layer, and a circular hole. The upper surface of the surfacing test plate is provided with a cylindrical blind hole, the cylindrical specimen is installed in the cylindrical blind hole, the cylindrical specimen and the cylindrical blind hole are in close contact and fit, the upper surface of the cylindrical specimen is flush with the upper surface of the surfacing test plate, the upper surfaces of the cylindrical specimen and the surfacing test plate are the cover surfacing layers, the cover surfacing layers are provided with a circular hole coaxial with the cylindrical blind hole, so that the cylindrical specimen is exposed, and the cylindrical specimen and the cover surfacing layer form a corrosion galvanic of dissimilar materials.

[0007] The method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water includes blanking, surfacing I, machining I, flaw detection, drilling I, cylindrical machining, cleaning, assembly, surfacing II, heat treatment, cutting, drilling II, cleaning, and packaging. The specific process is as follows:

[0008] (1) Cutting: by cutting, a test plate with a thickness of not less than 20 mm is obtained;

[0009] (2) Overlay welding I: Overlay welding is performed on the test plate to obtain a combined test piece of the test plate and the overlay welding layer test plate;

[0010] (3) Machining and flaw detection: cutting off the edge area, the top uneven area and the bottom of the weld overlay test plate to obtain a weld overlay test plate of specified size and smooth surface, and then flaw detection;

[0011] (4) Drilling I: Drilling a cylindrical blind hole on the surface of the weld cladding test plate;

[0012] (5) Cylindrical machining, processing cylindrical specimens;

[0013] (6) Cleaning and assembly: clean and assemble cylindrical blind holes and cylindrical specimens;

[0014] (7) Overlay welding II: applying a cover overlay welding layer on the surface of the overlay welding layer test plate with cylindrical specimens;

[0015] (8) Heat treatment: the whole specimen shall be subjected to post-weld heat treatment after surfacing welding;

[0016] (9) Cutting: Cut the test pieces according to the specified markings;

[0017] (10) Drilling II: drilling a hole in the cover weld layer on the surface of the test block to obtain the final galvanic corrosion test specimen;

[0018] (11) Clean and package the galvanic corrosion specimens.

[0019] In the method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water, in step (2), the surfacing process refers to the actual welding process of the specimen simulated by the galvanic corrosion specimen, and the thickness of the surfacing layer is determined by the final size of the galvanic corrosion specimen. The thickness of the surfacing layer is at least 3 mm larger than the final galvanic corrosion specimen size.

[0020] In the method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water, in step (3), the weld overlay test plate is subjected to flaw detection to eliminate the influence of welding defects in the weld overlay test plate, thereby ensuring the validity of the final galvanic corrosion sample and the accuracy of the galvanic corrosion test.

[0021] In the method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water, in step (4), the size of the weld overlay test plate is measured, and the specific positions of the drilling holes are determined, and the edge of the test plate corresponding to the positions of the two holes is marked, and a mechanical method is used for marking to prevent the mark from being lost in the subsequent preparation process.

[0022] The method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water, in step (5), a smooth cylindrical specimen is obtained by turning, the material of the cylindrical specimen is selected from the material specified in the test, and a corrosion couple is formed with the material of the cladding layer test plate.

[0023] The method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water comprises the following steps: in step (6), the weld overlay test plate, the cylindrical blind hole on the weld overlay test plate, and the cylindrical specimen are cleaned with alcohol or acetone to remove surface contamination during processing; the cylindrical specimen is assembled into the cylindrical blind hole on the weld overlay test plate, and in order to prevent large welding defects during subsequent weld overlay, the cylindrical specimen and the cylindrical blind hole should be tightly fitted.

[0024] The method for preparing a galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water comprises the following steps: in step (8), the whole specimen is subjected to post-weld heat treatment after surfacing welding, and the heat treatment process is consistent with the actual heat treatment process of the simulated specimen; and the upper surface of the cover surfacing layer of the whole specimen after the heat treatment is leveled.

[0025] In the method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water, in step (10), the exposed area of ​​the cylindrical sample material is controlled by controlling the aperture of the circular hole, thereby achieving control of the area ratio.

[0026] The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water comprises the following steps: in step (11), the galvanic corrosion sample is ultrasonically cleaned in alcohol or acetone, and the galvanic corrosion sample after ultrasonic cleaning is sealed and packaged to prevent pollutants from contaminating the circular hole.

[0027] The advantages and beneficial effects of the present invention are:

[0028] 1. In the present invention, no other materials (including traditional sealing materials) except the test materials are used, which eliminates the possibility of other materials affecting galvanic corrosion, and also enables the galvanic corrosion specimen to be directly tested in high-temperature and high-pressure primary circuit water;

[0029] 2. In the present invention, the cylindrical sample material is wrapped in the cladding material, exposed by drilling, and a galvanic couple is formed between the cladding materials, thereby simulating the real spatial position relationship between dissimilar materials in a nuclear power plant;

[0030] 3. In the present invention, the exposure area ratio between different materials is controlled by controlling the drilling hole diameter, which is simple, convenient and easy to operate;

[0031] 4. In the present invention, the surfacing process is the same as the actual welding process, thereby simulating the actual situation of the relevant components in the nuclear power plant to the greatest extent possible and ensuring the reliability of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1(a)-Figure 1(b) 1(a) is a front view, and 1(b) is a top view.

[0033] Figure 2(a)-Figure 2(b) It is a schematic diagram of the test piece after applying surfacing welding I. Among them, Figure 2 (a) is a front view, and Figure 2 (b) is a top view.

[0034] Figure 3(a)-Figure 3(b) Schematic diagram of drilling holes on the surface of the weld cladding test plate, wherein FIG3(a) is a main view and FIG3(b) is a top view.

[0035] Figure 4(a)-Figure 4(b) Schematic diagram of the cylindrical test, wherein FIG4(a) is a front view and FIG4(b) is a top view.

[0036] Figure 5(a)-Figure 5(b) Schematic diagram of the specimen after applying cover cladding II, wherein FIG5(a) is a front view and FIG5(b) is a top view.

[0037] Figure 6 Schematic diagram of the final galvanic corrosion specimen.

[0038] Figure 7 The photos of the final galvanic corrosion samples are shown in Figure 1. (a) The diameter of the circular hole is Φ1mm, (b) The diameter of the circular hole is Φ2mm, (c) The diameter of the circular hole is Φ4mm, (d) The diameter of the circular hole is Φ6mm, and (e) The diameter of the circular hole is Φ10mm.

[0039] In the figure, 1 is the test plate, 2 is the cladding layer test plate, 3 is the cylindrical blind hole, 4 is the mark, 5 is the cylindrical specimen, 6 is the cover cladding layer, 7 is the circular hole, A is the machined baseline 1, B is the machined baseline 2, C is the machined baseline 3, D is the machined baseline 4, E is the machined baseline 5, F is the machined baseline 6, and G is the machined baseline 7. DETAILED DESCRIPTION

[0040] like Figure 1(a)-Figure 1(b) , Figure 2(a)-Figure 2(b) , Figure 3(a)-Figure 3(b) , Figure 4(a)-Figure 4(b) , Figure 5(a)-Figure 5(b) , Figure 6 As shown, the method for preparing galvanic corrosion samples with strictly controlled area ratio in high temperature and high pressure water of the present invention mainly includes: blanking, surfacing I, machining I, flaw detection, drilling I, cylindrical machining, cleaning, assembly, surfacing II, heat treatment, cutting, drilling II, cleaning, packaging, etc. The specific preparation process is as follows:

[0041] like Figure 1(a)-Figure 1(b) As shown, materials with the same or similar composition as the test cladding layer are selected for blanking. Blanking needs to be determined according to the number and size of the samples to be prepared. Blanking can be carried out by various machining methods. The thickness of the obtained test plate 1 is generally not less than 20mm. The surface of the test plate 1 should be cleaned to avoid contamination of the composition of the cladding layer or serious welding defects during subsequent cladding.

[0042] like Figure 2(a)-Figure 2(b) As shown, surfacing I is performed on the surface of the test plate 1 obtained by cutting. The surfacing process refers to the actual welding process of the test piece simulated by the galvanic corrosion sample. The thickness of the surfacing layer is determined by the final size of the galvanic corrosion sample. In principle, the thickness of the surfacing layer should be at least 3 mm larger than the final galvanic corrosion sample size.

[0043] After the cladding is completed, machining I is performed. Machining I mainly involves cutting the combined test piece (test plate 1 and cladding layer test plate 2) obtained above, with the purpose of removing the edge area, the top area of ​​the cladding layer test plate 2 and the test plate 1 obtained by cutting, so as to obtain a cladding layer test plate 2 with a smooth surface and edge; machining I needs to be performed according to "machining baseline 1 (A)", "machining baseline 2 (B)", "machining baseline 3 (C)" and "machining baseline 4 (D)" in Figure 2, and the area with poor quality or uneven thickness of the edge cladding layer is removed, and "machining baseline 1 (A)", "machining baseline 2 (B)", "machining baseline 3 (C)" and "machining baseline 4 (D)" are machined. The "machined baseline 4 (D)" is distributed around the edges of the weld overlay surface; then the upper surface of the weld overlay test plate 2 is leveled according to the "machined baseline 5 (E)", and the "machined baseline 5 (E)" is 1 to 2 mm away from the upper surface of the weld overlay; then the test plate 1 is cut off according to the "machined baseline 6 (F)", and the "machined baseline 6 (F)" must be located in the weld overlay, and the distance between the upper surface of the test plate 1 and the lower surface of the weld overlay should be greater than 2 mm; the distance between the "machined baseline 6 (F)" and the "machined baseline 5 (E)" is determined by the specific sample design, and a weld overlay test plate 2 with a specified size and a smooth surface is obtained.

[0044] The cladding layer test plate 2 is subjected to flaw detection. The flaw detection is mainly performed on the cladding layer test plate 2 prepared by cladding I. The purpose is to eliminate the influence of larger welding defects in the cladding layer test plate 2, thereby ensuring the validity of the final galvanic corrosion specimen and the accuracy of the galvanic corrosion test.

[0045] like Figure 3(a)-Figure 3(b) As shown, the size of the weld overlay test plate 2 is measured, and the specific position of the drilling hole is determined. A mark 4 is made on the edge of the weld overlay test plate 2 corresponding to the position of the two holes. Mechanical methods should be used as much as possible when making marks to prevent the marks from being lost in the subsequent preparation process. Then, a hole I is drilled on the surface of the weld overlay test plate 2. The drilling hole I is mainly performed on the weld overlay test plate 2 obtained after machining I, and a cylindrical blind hole 3 of a certain size is obtained to provide a cylindrical space for the cylindrical specimen 5.

[0046] like Figure 4(a)-Figure 4(b) As shown, cylindrical machining is performed, and the cylindrical specimen 5 is machined, mainly to obtain a smooth cylindrical specimen 5 of a certain size. Generally, turning is used. The material is selected from the material specified in the test and forms a corrosion couple with the cladding layer material.

[0047] Alcohol or acetone is used to clean the weld overlay test plate 2, the cylindrical blind hole 3 on the weld overlay test plate 2, and the cylindrical sample 5 for 30 minutes to remove surface contamination during processing. The cylindrical sample 5 is assembled into the cylindrical blind hole 3 on the weld overlay test plate 2. In order to prevent large welding defects during subsequent weld overlay, the cylindrical sample 5 and the cylindrical blind hole 3 should be tightly matched. Therefore, the size should be strictly controlled during drilling I and cylindrical machining.

[0048] like Figure 5(a)-Figure 5(b) As shown, surfacing II is performed on the surface of the surfacing layer test plate 2 equipped with the cylindrical sample 5, and the cylindrical sample 5 is sealed in the surfacing layer test plate 2 to obtain the cover surfacing layer 6. The surfacing process refers to the actual welding process of the simulated specimen of the galvanic corrosion sample, and the thickness of the cover surfacing layer 6 is determined by the actual size of the simulated specimen. After surfacing, the entire specimen is subjected to post-weld heat treatment, and the heat treatment process is consistent with the actual heat treatment process of the simulated specimen.

[0049] For the whole specimen after heat treatment, the upper surface of the cap cladding layer 6 is leveled according to the "machined baseline 7 (G)". The distance between the "machined baseline 7 (G)" and the upper surface of the cap cladding layer 6 is determined by the specific sample design; then, the specimen is cut along the mark 4 to obtain the galvanic corrosion specimen. During the cutting process, the surface quality should be close to that of the actual part.

[0050] like Figure 6 As shown, a circular hole 7 is obtained by drilling II in the cover weld layer 6 on the surface of the weld layer test plate 2. The circular hole 7 is coaxial with the cylindrical blind hole 3, exposing the cylindrical sample 5 material sealed in the weld layer test plate 2, thereby forming a corrosion galvanic couple of dissimilar materials with the cover weld layer 6 material. The exposed area of ​​the cylindrical sample 5 material is controlled by controlling the aperture of the circular hole 7 to achieve control of the area ratio, and the final galvanic corrosion sample is obtained after drilling.

[0051] The galvanic corrosion test specimen is fully cleaned, generally by ultrasonic cleaning in alcohol or acetone for 30 minutes. The cleaned galvanic corrosion specimen is sealed and packaged, especially to prevent pollutants (such as water vapor, salt, etc.) from contaminating the circular hole.

[0052] In the present invention, the galvanic corrosion specimen mainly includes a surfacing test plate 2, a cylindrical blind hole 3, a cylindrical specimen 5, a cover surfacing layer 6, and a circular hole 7. The upper surface of the surfacing test plate 2 is provided with a cylindrical blind hole 3, and the cylindrical specimen 5 is installed in the cylindrical blind hole 3. The cylindrical specimen 5 and the cylindrical blind hole 3 are in close contact and fit. The upper surface of the cylindrical specimen 5 is flush with the upper surface of the surfacing test plate 2. The upper surfaces of the cylindrical specimen 5 and the surfacing test plate 2 are the cover surfacing layer 6. The cover surfacing layer 6 is provided with a circular hole 7 coaxial with the cylindrical blind hole 3, so that the cylindrical specimen 5 is exposed, and the cylindrical specimen 5 and the cover surfacing layer 6 form a corrosion galvanic of dissimilar materials.

[0053] Example

[0054] In this embodiment, the cylindrical specimen is processed by SA-508grade 3 low alloy steel, the surfacing material is 308L stainless steel, and the final galvanic corrosion specimen size is: length 30±0.1mm, width 30±0.1mm, height 35±0.1mm. Figure 7 As shown in (a)-(e), the specified sizes of the circular hole diameter are Φ1mm, Φ2mm, Φ4mm, Φ6mm, and Φ10mm, and the processing accuracy is ±0.1mm. The area ratios of SA-508grade 3 low alloy steel and 308L stainless steel are approximately 1:7188, 1:1798, 1:450, 1:200, and 1:72, respectively.

[0055] In a simulated primary circuit high temperature and high pressure water, the prepared galvanic corrosion samples with different openings (exposed areas) were subjected to a long-term immersion test, and the samples were taken out after immersion for 500h, 1000h, 2000h, 3000h, 4000h, and 5000h, respectively, for analysis. The test environment was a simulated primary circuit high temperature and high pressure water environment of 300℃, 1500ppm B, 2.3ppm Li, and high purity nitrogen deoxygenation. After the 5000h test, the sample was photographed as follows: Figure 7 As shown, the specimen meets the test and design requirements.

[0056] The results of the embodiment show that the materials used in the sample preparation process of the present invention are mainly determined by the materials specified in the test, and the area ratio between different materials is strictly controlled by controlling the aperture in the drilling II process. In the sample preparation process, no other packaging materials except the test materials are used, there is no risk of crevice corrosion, and the actual position (space) relationship between materials in actual use can be strictly simulated, which is particularly suitable for related galvanic corrosion experiments in high temperature and high pressure water environments. The present invention solves the problem that conventional packaging materials are not suitable for high temperature and high pressure water environments, can strictly control the area ratio and reflect the actual spatial position relationship, and effectively improve the accuracy and repeatability of the experiment.

Claims

1. A galvanic corrosion specimen with strictly controlled area ratio in high temperature and high pressure water, characterized in that: The galvanic corrosion specimen comprises a surfacing weld layer test plate, a cylindrical blind hole, a cylindrical specimen, a cover surfacing weld layer, and a circular hole. A cylindrical blind hole is provided on the upper surface of the surfacing weld layer test plate, and the cylindrical specimen is installed in the cylindrical blind hole. The cylindrical specimen and the cylindrical blind hole are in close contact and fit, and the upper surface of the cylindrical specimen is flush with the upper surface of the surfacing weld layer test plate. The upper surfaces of the cylindrical specimen and the surfacing weld layer test plate are the cover surfacing weld layers, and the cover surfacing weld layer has a circular hole coaxial with the cylindrical blind hole to expose the cylindrical specimen, so that the cylindrical specimen and the cover surfacing weld layer form a corrosion galvanic of dissimilar materials.

2. A method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 1, characterized in that: Including cutting, surfacing I, machining I, flaw detection, drilling I, cylindrical machining, cleaning, assembly, surfacing II, heat treatment, cutting, drilling II, cleaning, packaging, the specific process is as follows: (1) Cutting: by cutting, a test plate with a thickness of not less than 20 mm is obtained; (2) Overlay welding I: Overlay welding is performed on the test plate to obtain a combined test piece of the test plate and the overlay welding layer test plate; (3) Machining and flaw detection: cutting off the edge area, the top uneven area and the bottom of the weld overlay test plate to obtain a weld overlay test plate of specified size and smooth surface, and then flaw detection; (4) Drilling I: Drilling a cylindrical blind hole on the surface of the weld cladding test plate; (5) Cylindrical machining, processing cylindrical specimens; (6) Cleaning and assembly: clean and assemble cylindrical blind holes and cylindrical specimens; (7) Overlay welding II: applying a cover overlay welding layer on the surface of the overlay welding layer test plate with cylindrical specimens; (8) Heat treatment: the whole specimen shall be subjected to post-weld heat treatment after surfacing welding; (9) Cutting: Cut the test pieces according to the specified markings; (10) Drilling II: drilling a hole in the cover weld layer on the surface of the test block to obtain the final galvanic corrosion test specimen; (11) Clean and package the galvanic corrosion specimens.

3. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (2), the surfacing process refers to the actual welding process of the specimen simulated by the galvanic corrosion sample, and the thickness of the surfacing layer is determined by the final size of the galvanic corrosion sample. The thickness of the surfacing layer is at least 3 mm larger than the final galvanic corrosion sample size.

4. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (3), the weld overlay test plate is inspected to eliminate the influence of welding defects in the weld overlay test plate, thereby ensuring the validity of the final galvanic corrosion specimen and the accuracy of the galvanic corrosion test.

5. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (4), the dimensions of the weld overlay test plate are measured, and the specific positions of the drilling holes are determined. The edges of the test plate corresponding to the positions of the two holes are marked. The marking is done mechanically to prevent the marks from being lost during the subsequent preparation process.

6. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (5), a smooth cylindrical specimen is obtained by turning. The material of the cylindrical specimen is selected from the material specified in the test and forms a corrosion couple with the material of the weld overlay test plate.

7. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (6), the weld overlay test plate, the cylindrical blind hole on the weld overlay test plate, and the cylindrical sample are cleaned with alcohol or acetone to remove surface contamination during the processing; the cylindrical sample is assembled into the cylindrical blind hole on the weld overlay test plate. In order to prevent large welding defects during subsequent weld overlay, the cylindrical sample and the cylindrical blind hole should be tightly fitted.

8. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (8), the whole specimen is subjected to post-weld heat treatment after surfacing welding, and the heat treatment process is consistent with the actual heat treatment process of the simulated specimen; after the heat treatment, the upper surface of the cover surfacing layer of the whole specimen is leveled.

9. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (10), the exposed area of ​​the cylindrical sample material is controlled by controlling the aperture of the circular hole, thereby achieving control of the area ratio.

10. The method for preparing a galvanic corrosion sample with strictly controlled area ratio in high temperature and high pressure water according to claim 2, characterized in that: In step (11), the galvanic corrosion sample is ultrasonically cleaned in alcohol or acetone, and the galvanic corrosion sample after ultrasonic cleaning is sealed and packaged to prevent pollutants from contaminating the circular hole.

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