Evaluation method for flange forge piece of reactor pressure vessel

Abstract

The invention provides a method for evaluating a flange forge piece of a reactor pressure vessel, and relates to the technical field of manufacturing and production of the flange forge piece of the reactor pressure vessel. According to the evaluation method, the most representative position of the forging is selected according to the shape characteristics of the flange forging to cut a sample, and the sample is subjected to a tensile test, an impact test, a KV-T curve test, a drop weight test, a metallographic test, a grain size test, non-metallic inclusion determination and chemical component analysis. Various technical indexes of the reactor pressure vessel flange forge piece in the process evaluation stage can be comprehensively and effectively evaluated, and meanwhile the reasonability and feasibility of the flange forge piece manufacturing process can be verified.

Description

Technical Field

[0001] The invention relates to the technical field of reactor pressure vessel flange forging manufacturing and production, in particular to an evaluation method for reactor pressure vessel flange forging. Background Art

[0002] The reactor pressure vessel is an important component of the coolant pressure boundary of the reactor's primary circuit. It is used to contain the entire core and high-temperature and high-pressure coolant, and prevent the leakage of radioactive materials. The reactor pressure vessel flange forgings are mainly used to achieve the connection, support and sealing between pipelines or equipment to ensure the stable operation of the overall system. Reactor pressure vessel flange forgings usually have large size and weight, which can easily cause streamline disorder in the prefabricated blank during the forging process. Huge pressure needs to be applied during the forging process, and precise control is required during the heating, forming and cooling processes, otherwise the flange forgings will be deformed or internal stress will occur. Therefore, it is necessary to evaluate the quality of reactor pressure vessel flange forgings.

[0003] The reactor pressure vessel designed based on RCC-M "Design and Construction Rules for Mechanical Equipment of Pressurized Water Reactor Nuclear Island" requires forging assessment according to the provisions of RCC-M M140. The low-alloy steel main forgings of the reactor pressure vessel need to be tested and inspected for key performance indicators of the forgings to verify the rationality and feasibility of the manufacturing process. When testing and inspecting the key performance indicators of forgings, it is necessary to take samples from the forgings, but RCC-M only gives the principle requirements for forging sampling, and does not give specific sampling position requirements. Due to the large volume of flange forgings, the test results of samples at different positions vary greatly. Sampling and testing only according to the principle requirements in RCC-M will not reflect the performance of different parts of the flange forgings well, and the assessment of the flange forgings is far from enough, and it is impossible to comprehensively and completely evaluate the forging quality and forging process of the flange forgings. Summary of the invention

[0004] The object of the present invention is to provide an evaluation method for reactor pressure vessel flange forgings, which can comprehensively and effectively evaluate various technical indicators of reactor pressure vessel flange forgings in the process evaluation stage, and can also verify the rationality and feasibility of the flange forging manufacturing process.

[0005] Reactor pressure vessel flange forgings include top cover flange and container flange. As part of the pressure vessel, the main function of the top cover flange is connection and sealing, which refers more to the connection between the top of the container and other parts. The position and connection object of this flange are specific to the top of the container, ensuring the tight connection between the top structure and the container body to prevent leakage. Therefore, the design and processing of the top cover flange pay special attention to the sealing performance. The sealing surface forms include raised surface (RF), concave surface (FM), convex surface (M), tenon surface (T), groove surface (G), full plane (FF), etc. to meet different sealing requirements. At the same time, as an important component of the primary circuit bearing boundary and ensuring the sealing of the pressure vessel, the top cover flange of the reactor pressure vessel needs a smooth transition and uniform force to prevent excessive local stress.

[0006] The container flange usually refers to the flange connecting the cylinder and the head, the cylinder and the cylinder, or the head and the tube sheet, which combines different pressure-bearing components together, while ensuring that the connection parts do not leak, ensuring the safe operation and sealing of the container. The container flange for the reactor pressure vessel is used to seal the high-temperature, high-pressure, radioactive primary coolant and maintain pressure, while bearing dynamic loads and temperature loads. It plays a vital role in the operation of nuclear power plants, and its design and manufacturing must meet extremely high safety calibration and performance requirements.

[0007] The non-uniformity of the performance measurement values ​​of different parts of the top cover flange and container flange forgings is related to many factors, such as: the shape and quality of the forgings, smelting process, forging capacity and cooling rate, which will affect the deformation, microstructure, component segregation, inclusions, grain size, etc. of each part of the forgings. Even under the condition of certain forging smelting and forging process, the quenching cooling rate at different parts of the forging performance heat treatment is different, so the organization and performance also vary greatly. The cooling rate of the inner and outer walls is significantly higher than that of the center, and the hardened organization in the surface area will be more. With the increase of wall thickness, the cooling rate at the center of the forging decreases, and the hardened organization may not meet the design requirements. The above factors will cause differences in the performance measurement values ​​of different parts.

[0008] Based on the functions and requirements of the top cover flange and container flange, their forging process is relatively complex, and the structure after forming is also relatively complex. When evaluating their quality, it is more necessary to take targeted samples so that the test samples can fully reflect the quality of the top cover flange and container flange. Since it is impossible to take samples in all parts of the product performance test, the sampling position of the sample is required to be representative. The performance test results should be able to replace the actual performance of the product. It is necessary to select the most representative position of the forging according to the shape characteristics of the top cover flange and container flange forgings to cut the sample for inspection, so as to represent the comprehensive performance of the entire forging. The number of samples is also important for the performance evaluation of the top cover flange and container flange forgings. A sufficient number of samples can provide more comprehensive performance data.

[0009] The applicant took into account that carbon segregation is prone to occur at the nozzle end and the riser end of the flange forging during the forging process, so samples were taken at both ends for non-metallic inclusion inspection and chemical composition analysis; at the same time, considering the radial performance uniformity, samples were taken in layers for performance testing, making the technical assessment of the flange forging more complete and comprehensive.

[0010] Based on this, the present invention proposes an evaluation method for a reactor pressure vessel flange forging, wherein the flange forging includes a top cover flange and a vessel flange, and comprises the following steps:

[0011] (1) Three generatrixes parallel to the axis of the forging and spaced 120 degrees apart from each other are selected from the inner surface of the top cover flange and the container flange for sampling, and multiple samples are cut evenly spaced on the generatrix for chemical composition analysis;

[0012] (2) Grind the sulfur print inspection belt along three other generatrixes parallel to the axis of the forging and spaced 120° apart from each other, and perform the sulfur print inspection;

[0013] (3) Cut the sample at the position 40 mm from the inner surface of the nozzle end of the top cover flange for performance testing. Cut the sample at the position 40 mm from the inner surface of the nozzle end and the position 40 mm from the outer surface of the riser end at a 90° angle to the performance test sample for performance testing.

[0014] (4) Samples are cut for performance testing at the position where the nozzle end of the container flange is 1 / 4 of the wall thickness from the inner surface, and at the position where the riser end is 40 mm from the inner surface. Samples are cut for performance testing at the position where the nozzle end is 1 / 2 of the wall thickness from the inner surface, 3 / 4 of the wall thickness, the outer wall opposite the position of the performance sample at the riser end, and the inner wall, outer wall, and 1 / 2 of the wall thickness at a 90° angle between the riser end and the performance sample.

[0015] By cutting samples at multiple levels in the radial direction of the nozzle end face, riser end face, inner and outer walls, nozzle end and riser end of the forging, the typical area of ​​the forging is covered, which can represent and illustrate the overall performance of the flange forging. Through the test results, a comprehensive technical evaluation of the flange forging can be carried out from multiple dimensions such as smelting, forging, heat treatment, processing, sampling location, performance inspection, non-destructive inspection, etc., forming a complete and standardized comprehensive evaluation method, providing clear ideas and directions for the technical evaluation and process consolidation of reactor pressure vessel flange forgings.

[0016] Sampling is carried out at a position 40mm from the inner surface at the nozzle end and at a position 40mm from the inner surface / outer surface at the riser end. Compared with sampling in the wall thickness direction, sampling can be carried out separately in the circumferential and axial directions. Appropriate samples are selected for inspection according to the inspection items. The cut samples can fully cover the typical areas of the forgings, including high stress areas and surface areas. According to the inspection results, the forgings are evaluated from multiple dimensions to accurately judge the quality of the forgings.

[0017] Furthermore, in step (1), the spacing between adjacent samples on the same busbar is 200 mm. The sampling distance is limited to ensure the representativeness and accuracy of forging sampling and to avoid the influence of the sampling results on the unevenness of the heat treatment of the forging and the changes in the chemical composition and mechanical properties during the forging process.

[0018] Further, in step (2), the width of the sulfur print inspection tape is 100-150 mm. Limiting the width of the sulfur print inspection tape can ensure accurate measurement of sulfur distribution and avoid inspection errors caused by inspection areas that are too wide or too narrow. Such a limitation helps to improve the accuracy and reliability of the inspection, thereby ensuring that the quality of the forgings meets the standards and requirements. Preferably, it is 130 mm.

[0019] Further, in step (3), the sampling method is:

[0020] A circle with a radius of 40 mm and the center of the end face of the nozzle as the center is used as the first sampling line. Samples are taken at intervals of 30 mm along the first sampling line. The first extended surface is extended along the height direction of the top cover flange from the first sampling line as the starting point. Multiple samples are cut in layers at uniform intervals along the height direction on the first extended surface.

[0021] A circle with a radius of 40 mm and the center of the end face of the riser as the center is formed as the second sampling line, and samples are taken at intervals of 50 mm along the second sampling line. A second extended surface is formed by extending along the height direction of the top cover flange from the second sampling line as the starting point, and multiple samples are cut in layers at uniform intervals along the height direction on the second extended surface;

[0022] The first sampling line and the second sampling line are circumferential sampling, and the first extended surface and the second extended surface are axial sampling. This can meet the sampling requirements of different performance tests and cover typical areas of forgings. The sampling is representative and uniform. Under the conditions of line and surface sampling, layered and regional sampling can fully reflect the quality of forgings and help to comprehensively and effectively evaluate the various technical indicators of the reactor pressure vessel flange forging process evaluation stage.

[0023] Furthermore, in step (4), the sampling method is as follows: at each sampling position, a circle identical to the axis of the container flange is cut as a circumferential sampling line, and sampling is performed at intervals of 30 mm along the circumferential sampling line; at each sampling point, an axial sampling line parallel to the axis of the container flange is cut, and sampling is performed at intervals of 120 mm along the axial sampling line.

[0024] Among them, the wall thickness position, outer wall and inner wall are all radially sampled, which, combined with circumferential sampling and axial sampling, can cover different directions of the forging (longitudinal, transverse and height), making the sampling more representative. The sample test results can represent and explain the overall performance of the flange forging, and can accurately evaluate the forging process of the forging.

[0025] Furthermore, the sampling state of the test sample includes a performance heat treatment state and a simulated post-weld stress relief heat treatment state.

[0026] Furthermore, in the performance test, the tensile test temperatures are room temperature and 350°C, the impact test temperatures are -20°C, 0°C and 20°C, and the KV-T curve test should take at least 8 test temperatures, among which at least 3 specimens are tested at each test temperature.

[0027] Furthermore, the evaluation method also includes non-destructive testing, (a) performing 100% ultrasonic testing on the flange forging, the ultrasonic testing including straight probe testing and oblique probe testing; (b) performing magnetic particle testing on the non-surfacing surface of the flange forging, and performing magnetic particle testing or liquid penetration testing on the surface of the flange forging to be welded.

[0028] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0029] 1) A comprehensive technical assessment of low alloy steel flange forgings for reactor pressure vessels, which covers the entire process of forging manufacturing and can comprehensively and effectively evaluate various technical indicators in the process assessment stage of reactor pressure vessel flange forgings;

[0030] 2) It specifies the key processes and key parameters for evaluation in the manufacturing process, forming a complete and standardized comprehensive evaluation method, which can also verify the rationality and feasibility of the flange forging manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the reactor pressure vessel top cover flange;

[0032] Figure 2 It is a cross-sectional view of the reactor pressure vessel top cover flange;

[0033] Figure 3 It is a schematic diagram of the structure of the reactor pressure vessel flange;

[0034] Figure 4 It is a cross-sectional view of the reactor pressure vessel flange. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0036] For low alloy steel flange forgings for reactor pressure vessels, the most commonly used process flow is:

[0037] Smelting - forging - post-forging heat treatment - rough machining - performance heat treatment - finishing. The evaluation method of this embodiment is applicable to the above processes. Taking the top cover flange of the Hualong No. 1 reactor pressure vessel as an example, its specific implementation method is as follows:

[0038] (1) Smelting stage

[0039] The steel smelting should adopt electric furnace (EF) to smelt molten steel, and then vacuum refining in refining furnace. The steel ingot is cast by 3 bags of molten steel by vacuum casting process, and the total weight of steel ingot is 230 tons. The method of electric furnace rough refining + vacuum refining and vacuum casting process are the key processes for evaluation, the number of 3 bags of molten steel for co-casting is the key parameter for evaluation, and the weight of steel ingot is 230 tons (allowable deviation ±7%). At the same time, the impurity elements of raw materials for forgings should be strictly controlled, the impurity element P content is ﹤0.008%, the S content is ﹤0.005%, the Cu content is ﹤0.08%, and the chemical composition is in accordance with the relevant provisions of GB / T223.

[0040] (2) Forging stage

[0041] The forging process and forging sequence of forgings are key processes for evaluation. During forging, sufficient pressure should be ensured to deform the steel ingot deeply and complete plastic deformation under reasonable stress state to make the structure dense. The head and tail removal of forgings are key parameters for evaluation. The total forging ratio of forgings should be greater than 3, which is the key parameter for evaluation.

[0042] (3) Post-forging heat treatment stage

[0043] The normalizing + tempering process is adopted. The forgings are heated to the austenitizing temperature range and kept warm. After full austenitization, they are air-cooled to obtain a uniform and refined structure, and then tempered. The post-forging heat treatment process is the key process for evaluation. The number of heat treatments, normalizing temperature, tempering temperature, and holding time are the key parameters for evaluation. Thermocouples should be placed at the nozzle end and riser end of the forging to ensure that the positions of the expected maximum and minimum temperatures of the forging are covered. The maximum allowable deviation between the actual temperature of different parts of the forging being treated and the specified heat treatment temperature is ±10°C.

[0044] (4) Rough processing stage

[0045] The outer dimensions of the processed forgings should be as close as possible to those of the final product, but sufficient size should be left at the nozzle and riser ends of the forgings to cut test rings for performance testing. At the same time, sufficient margins should be left on the inner and outer walls of the forgings for subsequent defect removal (if any) and finishing processes.

[0046] (5) Performance heat treatment stage

[0047] The forging is heated in an electric furnace to the austenitizing temperature range (850℃~925℃) and kept warm to homogenize the austenite structure, and then quenched to fully transform the structure. Here, a multi-stage austenitizing heat treatment process can be selectively adopted according to the performance requirements of the forging (the forging is heated in an electric furnace to the austenitizing temperature range and kept warm to homogenize the austenite structure, and then quenched; then the forging is reheated to the critical temperature range, partially austenitized, and quenched again).

[0048] After completing the austenitization-quenching cycle, the forging is tempered at 635℃~665℃ to obtain a stable tempered bainite structure. The performance heat treatment process is the key process for evaluation, and the number of heat treatments, quenching temperature, tempering temperature, holding time, heating rate, and cooling rate are the key parameters for evaluation; thermocouples should be placed at the nozzle end and riser end of the forging to ensure that the positions of the expected maximum and minimum temperatures of the forging are covered. The maximum allowable deviation between the actual temperature of different parts of the forging being treated and the specified heat treatment temperature is ±10℃.

[0049] Therefore, the key processes and key parameters for evaluation formulated in this evaluation method are summarized as follows:

[0050] Smelting: smelting process, number of ladles, weight of ingots.

[0051] Forging: forging process, forging sequence, head / tail removal, total forging ratio.

[0052] Post-forging heat treatment: post-forging heat treatment process, number of heat treatments, normalizing temperature, tempering temperature, and holding time.

[0053] Performance heat treatment: performance heat treatment process, number of heat treatments, quenching temperature, tempering temperature, holding time, heating rate, cooling rate.

[0054] Sampling inspection: sample status, sampling location, and sampling quantity.

[0055] Non-destructive testing: acceptance criteria.

[0056] When evaluating key processes, the process method shall not be changed without authorization, otherwise the original forging evaluation results will be invalid. The key parameters of the evaluation are valid within the evaluation approval range, and exceeding the evaluation approval range will cause the original evaluation results to be invalid.

[0057] like Figure 1-4 As shown, this embodiment provides a method for evaluating a reactor pressure vessel flange forging, wherein the flange forging includes a top cover flange and a vessel flange, and includes the following steps:

[0058] (1) Three generatrixes parallel to the axis of the forging and spaced 120° apart from each other were selected from the inner surface of the top cover flange and the container flange for sampling. Multiple samples were cut evenly spaced on the generatrix for chemical composition analysis. The sample spacing was 200 mm.

[0059] (2) Grind the sulfur print inspection strips along three other generatrixes parallel to the axis of the forging and spaced 120° apart from each other. The width of the sulfur print inspection strips is 100-150 mm, and perform sulfur print inspection.

[0060] (3) Cut the sample at the position 40 mm from the inner surface of the nozzle end of the top cover flange for performance testing. Cut the sample at the position 40 mm from the inner surface of the nozzle end and the position 40 mm from the outer surface of the riser end at a 90° angle to the performance test sample for performance testing.

[0061] Specifically, a circle formed by taking the center of the end face of the nozzle as the center and taking the radius of 40 mm as the first sampling line is used as the first sampling line, sampling is performed at intervals of 30 mm along the first sampling line, and a first extension surface is formed by extending along the height direction of the top cover flange from the first sampling line as the starting point, and multiple samples are cut in layers at uniform intervals along the height direction on the first extension surface;

[0062] A circle with a radius of 40 mm and the center of the end face of the riser as the center is formed as the second sampling line, and samples are taken at intervals of 50 mm along the second sampling line. A second extended surface is formed by extending along the height direction of the top cover flange from the second sampling line as the starting point, and multiple samples are cut in layers at uniform intervals along the height direction on the second extended surface;

[0063] (4) Samples are cut for performance testing at the position of 1 / 4 wall thickness from the nozzle end of the container flange to the inner surface, and at the position of 40 mm from the inner surface from the riser end. Samples are cut for performance testing at the position of 1 / 2 wall thickness and 3 / 4 wall thickness from the nozzle end to the inner surface, at the outer wall and 1 / 2 wall thickness position opposite to the performance test sample position from the riser end, and at the inner wall, outer wall and 1 / 2 wall thickness position where the riser end is 90° away from the performance test sample;

[0064] Specifically: at each sampling position, cut a circle identical to the axis of the container flange as the circumferential sampling line, and sample along the circumferential sampling line at intervals of 30 mm; at each sampling point, cut an axial sampling line parallel to the axis of the container flange, and sample along the axial sampling line at intervals of 120 mm.

[0065] Among them, steps (1) and (2) are the preliminary inspection stage. The preliminary inspection is an additional requirement for the evaluation of forgings. The inspection at this stage can identify in advance the risks of forgings producing excessive defects, carbon segregation, excessive impurity elements, etc. during the forging process, and is predictive and necessary in the early stage of manufacturing.

[0066] Performance testing includes three categories: chemical composition analysis, metallographic testing and mechanical properties testing:

[0067] 1) The chemical composition needs to detect the content of C, Si, Mn, P, S, Cr, Ni, Mo, V, Cu, Al, Co, As, Sn, Sb, B, N, H, and O elements, and calculate the welding reheat crack sensitivity coefficient and carbon equivalent. Special attention should be paid to the control of impurity elements. For the top cover flange and container flange forgings, the P element content needs to be controlled below 0.008%, the S element content needs to be controlled below 0.005%, and the Cu element content needs to be controlled below 0.08%;

[0068] The chemical composition shall be determined in accordance with the relevant provisions of GB / T 223. Other testing standards and methods with a testing accuracy not less than that of GB / T223 may also be used. If there is a dispute over the test results of a certain element, the test results of GB / T223 shall prevail;

[0069] 2) The metallographic structure should measure the grain size of the material, evaluate the non-metallic inclusions, and provide metallographic photos;

[0070] 3) Mechanical property tests include tensile test, impact test, KV-T curve test and drop hammer test. The tensile test sampling is circumferential, the sample state includes HTMP state and HTMP+SSRHT state, the test temperature includes room temperature and 350℃, and the tensile strength, yield strength, elongation after fracture and cross-sectional shrinkage of the material should be obtained respectively; the impact test sampling includes circumferential and axial directions, the sample state includes HTMP state and HTMP+SSRHT state, the test temperature includes -20℃, 0℃ and 20℃, and the impact absorption energy and lateral expansion value should be obtained respectively; the KV-T curve test sampling is axial, the sample state includes HTMP state and HTMP+SSRHT state, at least 8 test temperatures should be taken, and a complete KV-T curve and upper platform energy should be obtained; the drop hammer test sampling is circumferential, the sample state is HTMP+SSRHT state, and the reference non-plastic transition temperature should be obtained.

[0071] After sampling and inspection, non-destructive inspection of forgings is also included, specifically: (a) 100% ultrasonic inspection of the processed reactor pressure vessel flange forgings. Ultrasonic inspection includes straight probe inspection and oblique probe inspection. The straight probe inspection results should meet the requirements of quality level II in Table 12 of NB / T 20003.2-2021. During oblique probe inspection, there should be no defect display with echo amplitude exceeding 100% of the DAC curve; (b) Magnetic particle inspection is performed on the non-surfacing surface of the processed reactor pressure vessel flange forgings. The surface that needs to be surfacing can be selectively subjected to magnetic particle inspection or liquid penetration inspection.

[0072] Through the above multi-dimensional comprehensive evaluation, a complete and standardized comprehensive assessment method is formed.

[0073] Test results

[0074] Table 1 Chemical composition analysis of top cover flange (mass fraction %)

[0075]

[0076]

[0077] Table 2 Chemical composition analysis of container flange (mass fraction %)

[0078]

[0079]

[0080] Among them, the mass fractions of chemical components are all average values.

[0081] According to Table 1-2, the chemical element segregation of each part of the top cover flange and container flange forgings is controlled within the qualified range, and the deviation of the chemical composition of each part is very small, indicating that the composition of each part of the top cover flange and container flange forgings is uniform and the content of impurity elements is very low.

[0082] Table 3 Tensile test results

[0083]

[0084] Among them, the sample states include HTMP state and HTMP+SSRHT state. The data in the table are for the former state and for the latter state.

[0085] According to Table 3, from the tensile test results of various parts of the top cover flange and the container flange, the strength value fluctuation between the various parts is small and the strength distribution is uniform.

[0086] In summary, the present invention conducts sampling tests on different parts of the top cover flange and the container flange, covering typical areas of the flange forgings, which can represent and illustrate the overall performance of the flange forgings, and can comprehensively and effectively evaluate the various technical indicators of the reactor pressure vessel flange forgings in the process evaluation stage, while verifying the rationality and feasibility of the flange forging manufacturing process.

[0087] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating reactor pressure vessel flange forgings, characterized in that: The flange forging comprises a top cover flange and a container flange, and comprises the following steps: (1) Three generatrixes parallel to the axis of the forging and spaced 120 degrees apart from each other are selected from the inner surface of the top cover flange and the container flange for sampling, and multiple samples are cut evenly spaced on the generatrix for chemical composition analysis; (2) Grind the sulfur print inspection belt along three other generatrixes parallel to the axis of the forging and spaced 120° apart from each other, and perform the sulfur print inspection; (3) Cut the sample at the position 40 mm from the inner surface of the nozzle end of the top cover flange for performance testing. Cut the sample at the position 40 mm from the inner surface of the nozzle end and the position 40 mm from the outer surface of the riser end at a 90° angle to the performance test sample for performance testing. (4) Samples are cut for performance testing at the position where the nozzle end of the container flange is 1 / 4 of the wall thickness from the inner surface, and at the position where the riser end is 40 mm from the inner surface. Samples are cut for performance testing at the position where the nozzle end is 1 / 2 of the wall thickness from the inner surface, 3 / 4 of the wall thickness, the outer wall opposite the position of the performance sample at the riser end, and the inner wall, outer wall, and 1 / 2 of the wall thickness at a 90° angle between the riser end and the performance sample.

2. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: In step (1), the spacing distance between adjacent samples on the same busbar is 200 mm.

3. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: In step (2), the width of the sulfur print inspection tape is 100-150 mm.

4. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: In step (3), the sampling method is: A circle with a radius of 40 mm and the center of the end face of the nozzle as the center is used as the first sampling line. Samples are taken at intervals of 30 mm along the first sampling line. The first extended surface is extended along the height direction of the top cover flange from the first sampling line as the starting point. Multiple samples are cut in layers at uniform intervals along the height direction on the first extended surface. A circle with a radius of 40 mm and the center of the end face of the riser as the center is used as the second sampling line. Sampling is carried out at intervals of 50 mm along the second sampling line. The second extended surface is extended along the height direction of the top cover flange with the second sampling line as the starting point. On the second extended surface, multiple samples are cut in layers at uniform intervals along its height direction.

5. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: In step (4), the sampling method is as follows: at each sampling position, a circle identical to the axis of the container flange is cut as a circumferential sampling line, and sampling is performed at intervals of 30 mm along the circumferential sampling line; at each sampling point, an axial sampling line parallel to the axis of the container flange is cut, and sampling is performed at intervals of 120 mm along the axial sampling line.

6. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: The sampling states of the test materials include the performance heat treatment state and the simulated post-weld stress relief heat treatment state.

7. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: In the performance test, the tensile test temperatures are room temperature and 350°C, the impact test temperatures are -20°C, 0°C and 20°C, and the KV-T curve test should take at least 8 test temperatures, among which at least 3 specimens are used for testing at each test temperature.

8. The reactor pressure vessel flange forging evaluation method according to claim 1, characterized in that: The evaluation method also includes non-destructive testing, (a) 100% ultrasonic testing of flange forgings, ultrasonic testing including straight probe testing and oblique probe testing; (b) magnetic particle testing of non-surfacing surfaces of flange forgings, and magnetic particle testing or liquid penetration testing of surfaces of flange forgings that require surfacing.

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