Preparation method of gradient quality control sample for nickel-based superalloy nitrogen element analysis

Abstract

The invention discloses a preparation method of a gradient quality control sample for nickel-based high-temperature alloy nitrogen element analysis, and belongs to the technical field of material preparation and element analysis. The gradient quality control sample for nickel-based superalloy nitrogen element analysis is obtained through homogenization treatment, two times of upsetting and drawing deformation treatment, surface turning, uniformity inspection and constant value analysis, and the problem that gradient introduction of nitrogen elements in the field of nickel-based superalloy material preparation is difficult is solved. A set of matrix-matched high-temperature alloy gradient quality control sample is provided for determining the nitrogen element by an inert gas melting thermal conductivity method (relative method), a high-temperature alloy nitrogen element quality determination system is perfected, and the accuracy and traceability of nitrogen element determination of the high-temperature alloy sample are ensured; and meanwhile, the blank of the nitrogen element gradient quality control sample of the nickel-based high-temperature alloy sample is filled.

Description

Technical Field

[0001] The invention belongs to the technical field of material preparation and element analysis, and in particular relates to a method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy. Background Art

[0002] Due to its excellent high-temperature strength, oxidation resistance and corrosion resistance, high-temperature alloys are widely used in the preparation of core components of major equipment such as aerospace, ships and energy. The structure and properties of high-temperature alloy components are affected by the chemical composition. Therefore, the accurate control and determination of the chemical composition has always been the focus of industry research. Among them, nitrogen, as an interstitial element and the main element in the formation of nitrides, has a great influence on the performance of high-temperature alloys, and its composition must be strictly specified in various high-temperature alloys. The nitrogen content is mainly determined by the smelting process of the high-temperature alloy, but the control range of nitrogen content varies greatly in different nickel-based high-temperature alloys. For example, the nitrogen content in the most commonly used GH4169 alloy is 30~60ppm, with an upper limit of 100ppm; the content of nitrogen in the disk is 20~60ppm. The nitrogen content in nickel-based high-temperature alloys is 10-20ppm, with an upper limit of 32ppm; for solid solution strengthened nickel-based high-temperature alloys, nitrogen is considered to be a strengthening phase that is beneficial to material strength and can be controlled at 100-400ppm. On the one hand, nitrogen can act as an interstitial strengthening element to improve strength and corrosion resistance; on the other hand, it is also a nitride-forming element, and the nitride inclusions formed have an impact on the fatigue properties of the material. Therefore, strict control and rapid and accurate detection of nitrogen in various nickel-based high-temperature alloys are of great significance to the quality control and cost control of high-temperature alloy products.

[0003] The most commonly used and recognized method for nitrogen testing of high-temperature alloys is the inert gas melting thermal conductivity method. This method uses direct solid sampling and is a relative method, so it is heavily dependent on quality control samples. It requires a series of quality control samples of the same type to draw a calibration curve, and single-point quality control samples of the same type to be used as control samples to correct the test results of the samples to be tested or as quality control samples to control the measurement quality. However, there is currently a lack of dedicated quality control samples for nitrogen analysis of high-temperature alloys, and standard samples of steel are usually used in the actual analysis process. There is a big difference between the iron-based composition of steel and the nickel-based composition commonly used in high-temperature alloys, which affects the accuracy of the nitrogen analysis results of high-temperature alloys. However, with the continuous improvement of the requirements for the quality stability of high-temperature alloys in high-end equipment such as aircraft engines, the accurate determination of alloy components has become increasingly urgent.

[0004] In order to improve the accuracy of nitrogen analysis of high-temperature alloys by inert gas melting thermal conductivity method, it is urgent to develop a set of high-temperature alloy granular gradient quality control samples of nitrogen to solve the problem of its lack. There are two main difficulties in its preparation. First, due to the complexity of the matrix of high-temperature alloys, multiple smelting is required. As a gas element, nitrogen is difficult to reach the target content in a gradient and accurately. On the other hand, the prepared quality control samples need a more accurate method to determine the composition to ensure the accuracy and traceability of the value, but there is currently a lack of a more accurate determination method for nitrogen. Summary of the invention

[0005] The present invention proposes a method for preparing a gradient quality control sample for analyzing the nitrogen element in a nickel-based high-temperature alloy, which solves the problem of the lack of gradient quality control samples due to the difficulty in accurate gradient control and inability to trace the value of the nitrogen element in the nickel-based high-temperature alloy. The gradient quality control sample of the present invention can accurately analyze the nitrogen element in the nickel-based high-temperature alloy, ensure its traceability, and guarantee the service safety of the nickel-based high-temperature alloy in major equipment.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy, comprising the following steps:

[0008] Taking GH3536 nickel-based superalloy as the matrix, ingots with gradient nitrogen content were prepared. Ingots were named N1 to N5 in descending order according to the nitrogen content. Ingot N1 was GH3536 nickel-based superalloy.

[0009] Performing homogenization treatment on the N1-N5 ingots;

[0010] The ingot subjected to the homogenization treatment is subjected to two upsetting deformation treatments to obtain a rod;

[0011] The bar is surface polished and processed into a specification of 30mm~ For small bars of 100 mm, the uniformity of the small bars is initially inspected at the head, middle and tail positions;

[0012] The small bars that have passed the initial inspection are processed into 6.35mm alternative material;

[0013] Conducting uniformity inspection and fixed value analysis on the candidate materials, wherein the fixed value analysis method includes an inert gas melting thermal conductivity method and a prompt gamma neutron activation analysis k0 standard method;

[0014] When using the gradient quality control sample, the sample weight is >20 mg.

[0015] The nitrogen content in nickel-based high-temperature alloys is mainly determined by the smelting process and raw materials. Combined with the requirements for controlling the content of nitrogen in nickel-based high-temperature alloys and the actual use needs, the present invention selects the GH3536 nickel-based high-temperature alloy with a larger amount as the base material. The content of elements that are easily combined with nitrogen (such as Ti and Nb) in this material is relatively low. Ingots N1 to N5 with different nitrogen contents are prepared to solve the problem that nitrogen is difficult to add gradually during the melting and casting process in nickel-based high-temperature alloys, and at the same time solve the problem that nitrogen is difficult to be uniform. The nitrogen content in ingot N1 refers to the nitrogen present in the raw material (i.e., GH3536 nickel-based high-temperature alloy), and ingots N2 to N5 are respectively made of high-nitrogen ferrochrome according to weight and content to achieve nitrogen content regulation.

[0016] Before the N1-N5 ingots are homogenized, the N1-N5 ingots are treated as follows: the head and tail of the N1-N5 ingots are cut off to reveal the metallic luster, and there is no looseness and shrinkage cavity visible to the naked eye. The ingots after the above treatment are homogenized at high temperature for a long time, so that the gradient quality control samples can meet the requirements of element uniformity and consistency.

[0017] After two upsetting deformation treatments, the as-cast structure of the ingot is completely broken and the composition is further uniform.

[0018] The GH3536 nickel-based high-temperature alloy includes the following components in terms of mass percentage: Fe: 17%~20%, Cr: 20.5%~23%, Mo: 8%~10%, Co: 0.5%~2.5%, W: 0.2%~1%, C: 0.05~0.15%, Ti≤0.15%, N≤0.04%, and Ni: balance.

[0019] The steps for preparing the ingot with gradient nitrogen content are: adding high nitrogen ferrochrome into a matrix, and preparing the ingot with gradient nitrogen content by vacuum induction melting.

[0020] The gradient of the gradient nitrogen content in the ingot is: the N content of ingot N1 is 0.0005~0.003wt%, the N content of ingot N2 is 0.003~0.007wt%, the N content of ingot N3 is 0.007~0.015wt%, the N content of ingot N4 is 0.015~0.025wt%, and the N content of ingot N5 is 0.025~0.045wt%, wherein the range values ​​of the N content do not include the upper limit endpoint value.

[0021] The steps of the homogenization treatment are: heating to 1160-1200° C. at 1-10° C. / min, keeping the temperature for 40-80 hours, and cooling to room temperature after the end of the heat preservation.

[0022] The deformation temperatures of the two upsetting deformation treatments are both 1140-1160°C, the heating rates are both 1-5°C / min, the holding time is not less than 4h, and the single deformation amount is both 30-60%.

[0023] The bar material after the two upsetting deformation treatments is 32~ 102mm round bar.

[0024] In the inert gas melting thermal conductivity method, the analysis power is 5.5 KW, the analysis time is 180 s, and the reference reagent is potassium nitrate (purity> 99.9%).

[0025] The specific method of the prompt gamma neutron activation analysis k0 standard method is: the gradient quality control sample to be tested and potassium chloride are packed with carbonate, and 7×10 9 n / s 14MeV neutron beam irradiation for 10 minutes, cooling for 2 minutes respectively, measuring the analytical sensitivity ratio of nitrogen element and comparator in turn, and then using the wide energy range efficiency calibration curve to obtain the k0 value;

[0026] The comparator is 36 1951KeV gamma ray of Cl.

[0027] According to the wide energy range efficiency calibration curve, 36 The 1951KeV gamma rays emitted by the Cl nuclear reaction and 15 The 1884KeV gamma ray emitted by the N nuclear reaction corresponds to Substituting into equation (1), we can obtain the value of k0:

[0028] (1)

[0029] Substituting the k0 value into formula (2) we can calculate the nitrogen content (C x ),

[0030] (2)

[0031] The x's represent the parameters of the element to be measured, and the c's represent the comparator parameters.

[0032] A p , counting rate per unit weight (Bq / g);

[0033] A sp , counting rate per unit weight (Bq / μg);

[0034] , the absolute detection efficiency of the full energy peak;

[0035] C x Unit: μg / g.

[0036] The present invention uses prompt gamma neutron activation analysis single comparator k0 method, and selects Cl( 36 Cl) as a single comparator and high-purity potassium chloride (purity of 99.8%) as the standard to achieve quantitative analysis of nitrogen in gradient quality control samples.

[0037] Compared with the prior art, the present invention has the following advantages and technical effects:

[0038] The present invention solves the problem of the difficulty of introducing nitrogen in a gradient in the field of nickel-based high-temperature alloy material preparation. It provides a set of matrix-matched high-temperature alloy gradient quality control samples for the determination of nitrogen by the inert gas melting thermal conductivity method (relative method), improves the quality determination system of nitrogen in nickel-based high-temperature alloys, and ensures the accuracy and traceability of nitrogen determination in nickel-based high-temperature alloy samples.

[0039] The present invention fills the gap in the nitrogen element gradient quality control samples of nickel-based high-temperature alloy samples. Nitrogen is one of the elements that must be tested in nickel-based high-temperature alloy testing. The raw materials of the gradient quality control samples used in the present invention can be repeatedly prepared at a low cost, which can provide a reference for the preparation of other gas element quality control samples. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0044] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0045] An embodiment of the present invention provides a method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy:

[0046] The nitrogen content in the nickel-based high-temperature alloy is mainly determined by the smelting process and raw materials. Combined with the content control requirements and actual use requirements of the nitrogen element in the nickel-based high-temperature alloy, the present invention uses GH3536 nickel-based high-temperature alloy as a matrix to prepare ingots with gradient nitrogen content, which are named N1 to N5 ingots from low to high according to the nitrogen content. Ingot N1 is GH3536 nickel-based high-temperature alloy. GH3536 nickel-based high-temperature alloy includes the following components in terms of mass percentage: Fe: 17%~20%, Cr: 20.5%~23%, Mo: 8%~10%, Co: 0.5%~2.5%, W: 0.2%~1%, C: 0.05~0.15%, Ti≤0.15%, N≤0.04%, Ni: balance. The present invention designs five ingots with gradient content, which are named N1 to N5 quality control samples from low to high according to the nitrogen content. The nitrogen content in ingot N1 refers to The nitrogen element present in the raw material (i.e., GH3536 nickel-based high-temperature alloy), ingots N2 to N5 are respectively added with high-nitrogen ferrochrome according to weight and content to achieve the regulation of nitrogen content, the N content of ingot N1 is 0.0005-0.003wt%, the N content of ingot N2 is 0.003-0.007wt%, the N content of ingot N3 is 0.007-0.015wt%, the N content of ingot N4 is 0.015-0.025wt%, and the N content of ingot N5 is 0.025-0.045wt%, wherein the range values ​​of the N content do not include the upper limit endpoint value, and the expanded uncertainty is given after fully referring to factors such as the material preparation level, the test level, the actual application requirements, and the level of quality control samples with similar components at home and abroad. The present invention solves the problem that the nitrogen element in the nickel-based high-temperature alloy is difficult to be added gradually during the melting and casting process. When the gradient quality control sample of the present invention is used, the sample weight is greater than 20mg;

[0047] Cut off the head and tail of the N1-N5 ingots to reveal the metallic luster, without visible looseness and shrinkage cavities, and perform homogenization treatment on the N1-N5 ingots: heat up to 1160-1200° C. at a rate of 1-10° C. / min, keep the temperature for 40-80 hours, and cool to room temperature after the end of the heat preservation;

[0048] The homogenized ingot is subjected to two upsetting deformation treatments to completely break the as-cast structure and further promote the uniformity of the composition. 32~ For 102mm bars, the deformation temperature of the two upsetting deformation treatments is 1140~1160℃, the heating rate is 1~5℃ / min, the holding time is not less than 4h, and the single deformation is 30~60%;

[0049] The surface of the bar is polished and processed into specifications 30mm~ For 100mm small bars, perform a preliminary uniformity inspection at the head, middle and tail of the small bars;

[0050] The small bars that have passed the initial inspection are processed into 6.35mm alternative material;

[0051] Eight units with standard sample value determination qualifications were selected for value determination analysis. The selected units have passed CNAS accreditation or qualification certification and have the standard sample value determination testing capabilities that meet the requirements. The gradient quality control sample for nitrogen element in nickel-based high-temperature alloy of the present invention uses the inert gas melting thermal conductivity method (ISO 10720 potassium nitrate reference reagent method) and prompt gamma neutron activation analysis k0 standard method in the value determination process, which ensures the accuracy and traceability of the value.

[0052] In the present invention, "high nitrogen ferrochrome" refers to high nitrogen ferrochrome that complies with the YB / T 4135-2016 standard. The YB / T4135-2016 standard stipulates that high nitrogen ferrochrome is divided into three grades according to nitrogen content: HNCF10, HNCF15 and HNCF20. Among them, the nitrogen content of HNCF10 is not less than 10%, the nitrogen content of HNCF15 is not less than 15%, and the nitrogen content of HNCF20 is not less than 20%.

[0053] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0054] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in the art and are not the focus of the present invention.

[0055] The technical solution of the present invention is further illustrated by the following embodiments.

[0056] Example 1

[0057] (1) A GH3536 nickel-based high-temperature alloy (comprising the following components, in terms of mass percentage: Fe: 18.5%, Cr: 21.8%, Mo: 9%, Co: 1.5%, W: 0.6%, C: 0.08%, Ti: 0.02%, N: 0.0005-0.003, Ni: balance) was used as a matrix to prepare ingots with gradient nitrogen content. The ingots were named N1 to N5 in descending order according to the nitrogen content. Ingot N1 was a GH3536 nickel-based high-temperature alloy. Ingots N2 to N5 were prepared by adding 0.3 kg, 0.6 kg, 1.2 kg, and 2.6 kg of HNCF10 high-nitrogen ferrochrome to a 600 kg matrix, respectively, to achieve nitrogen content control. The designed component contents (wt%) and expected uncertainties (%) of ingots N1 to N5 in this embodiment are shown in Table 1.

[0058] Table 1 Designed content (wt%) and expected uncertainty (%) of gradient quality control samples

[0059]

[0060] (2) The ingot is prepared by adding the matrix and / or HNCF10 high nitrogen ferrochrome into vacuum induction melting according to the above ratio to prepare 305mm vacuum induction ingot, each weighing 600kg, is then electroslag remelted after cutting, trimming, and surface polishing (exposing metallic luster, without visible looseness and shrinkage), and the diameter of the obtained electroslag ingot is 406mm;

[0061] (3) Perform high-temperature homogenization treatment on the electroslag ingot: heat it to 1190°C at a rate of 2°C / min, keep it at this temperature for 60 hours, take it out of the furnace and cool it to room temperature after the end of the heat preservation to ensure uniform composition;

[0062] (4) The ingot that has undergone high-temperature homogenization treatment is subjected to two upsetting and drawing deformation treatments: the first upsetting deformation is 30%, the deformation temperature is 1150°C, and the holding time is 4h; the drawing deformation is 30%, the deformation temperature is 1150°C, and the holding time is 4h. The second upsetting deformation is 40%, the deformation temperature is 1150°C, and the holding time is 4h; the drawing deformation is 40%, the deformation temperature is 1150°C, and the holding time is 4h. After the two upsetting and drawing deformation treatments, the intermediate billet is drawn to 80mm round bar, deformation temperature is 1150℃, single deformation is 35%. Then rolling, single drawing deformation is 30%, deformation temperature is 1150℃, holding time is 4h, and preparation is 33mm small size rolled bars;

[0063] (5) After the small-sized rolled bars are polished on the surface, they are processed into For the 30 mm rolled rods, one rolled rod was taken every three rolled rods for component analysis, and the head, middle and tail of each rolled rod (5 grains were cut from each part) were analyzed for component analysis. The test results are shown in Table 2. The nitrogen content was consistent with the expected component design, and the RSD values ​​of the samples were less than 5%. The rolled rods prepared by the present invention met the initial inspection and analysis of the component uniformity of the quality control samples and met the conditions for preparing standard substances.

[0064] Table 2 Summary of initial inspection (%)

[0065]

[0066] (6) 30mm rolled rods according to 6.35mm is an alternative material for gradient quality control samples. The packaging material is a high-density polyethylene bottle with a capacity of 15mL, and each bottle contains 50 tablets. The minimum packaging unit number of each sample is 500 bottles. The samples packaged into the minimum packaging unit are subjected to uniformity inspection according to JJF1343-2012 "General Principles and Statistical Principles for the Determination of Standard Materials". 20 bottles are randomly selected and numbered 1-20 in sequence. They are measured in the following order, and each bottle is measured three times.

[0067] First time: 1-3-5-7-9-11-13-15-17-19-2-4-6-8-10-12-14-16-18-20;

[0068] Second time: 20-19-18-17-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-1;

[0069] The third time: 2-4-6-8-10-12-14-16-18-20-1-3-5-7-9-11-13-15-17-19;

[0070] The inert gas melting thermal conductivity method (refer to GB / T20124-2006) was used for determination, with the minimum sample weight being 1.0 g. The test results were statistically analyzed using the single factor variance analysis method. All F statistics were less than the F critical value of 1.85, which can meet the requirements for the uniformity of national standard materials. The test results are shown in Table 3.

[0071] Table 3 Summary of statistical results of uniformity test (%)

[0072]

[0073] (7) In accordance with GB / T15000.1~15000.8 “Guidelines for Standard Samples”, a total of 8 laboratories (referred to as units 1~8) participated in the determination analysis. The determination methods mainly adopted the inert gas fusion thermal conductivity method (ISO 10720 potassium nitrate reference reagent method), the neutron activation method (prompt gamma neutron activation analysis k0 standard method) and the inert gas fusion thermal conductivity method (refer to GB / T20124-2006).

[0074] Inert gas fusion thermal conductivity method (ISO 10720 potassium nitrate reference reagent method):

[0075] The sample weight is 1.0g, the flux is 0.2g nickel foil, the graphite crucible, and the instrument setting parameters are: analysis power 5.5KW, analysis time 180s. The reference reagent (purity>99.9%) potassium nitrate is dried and cooled to room temperature to prepare the calibration curve of nitrogen content (0%~0.05%) shown in Table 4.

[0076] Table 4 Calibration curve of nitrogen content

[0077]

[0078] Neutron activation method (prompt gamma neutron activation analysis k0 standard method):

[0079] Using prompt gamma neutron activation analysis single comparator k0 method, Cl( 36 Cl 1951 KeV γ-ray) as a single comparator, with high-purity potassium chloride as the standard. Accurately weigh 50 mg of the gradient quality control sample to be tested and 1.0 g of high-purity potassium chloride, and pack them in high-purity carbonate, respectively, with 7×10 9 Irradiate with 14MeV neutron beam count rate of n / s for 10 minutes, cool down for 2 minutes respectively, measure the analytical sensitivity ratio of nitrogen element and comparator in turn, and find out according to the wide energy range efficiency calibration curve 36 The 1951KeV gamma rays emitted by the Cl nuclear reaction and 15 The 1884KeV gamma ray emitted by the N nuclear reaction corresponds to Substituting into formula (1), we can obtain the value of k0:

[0080] (1)

[0081] Substituting the k0 value into formula (2) we can calculate the nitrogen content (C x ),

[0082] (2)

[0083] The x's represent the parameters of the element to be measured, and the c's represent the comparator parameters.

[0084] A p , counting rate per unit weight (Bq / g);

[0085] A sp , counting rate per unit weight (Bq / μg);

[0086] , the absolute detection efficiency of the full energy peak;

[0087] C x Unit: μg / g.

[0088] Inert gas fusion thermal conductivity method (refer to GB / T 20124-2006): Three granular standard samples for steel nitrogen analysis (purchased from Shanghai Wugang Co., Ltd. of Baosteel Group, Shanghai Iron and Steel Research Institute and Baoshan Iron & Steel Co., Ltd.) were selected to draw the standard curve, and the nitrogen content was between 0.001% and 0.05%. The weight of the standard sample and the sample was 1.0g, and the instrument setting parameters were: analysis power 5.5KW, analysis time 180s.

[0089] The fixed value units (units 1 to 8) and the fixed value methods are shown in Table 5.

[0090] Table 5 Summary of various fixed value units and fixed value methods

[0091]

[0092] (8) The Shapiro-Wilk method was used to test whether all the fixed value data of each unit obeyed the normal distribution. The average value of the data obeying the normal distribution was taken as the single measurement value to form a new set of data for testing by the Grubbs method. Then, the Cochran method was used to test whether the data of each group were of equal precision. After processing each group of data, the arithmetic mean and standard deviation of each group of data were calculated. The significant digits of the standard value were rounded according to GB 8170 "Data Rounding Rules". The obtained data are the standard values ​​of the high-temperature alloy nitrogen series quality control samples. The results are shown in Table 6.

[0093] Table 6 Standard values ​​and uncertainties (%) of gradient quality control samples for nitrogen analysis of nickel-based superalloys

[0094]

[0095] Comparative Example 1

[0096] The same as Example 1, except that the high temperature homogenization treatment in step (3) is not performed.

[0097] When performing the component analysis in step (5), the nitrogen content of the rolled rod varies greatly from head to tail, which does not meet the uniformity requirement, and the nitrogen contents of the five N1 to N5 do not show a gradient.

[0098] Comparative Example 2

[0099] The same as Example 1, except that in step (4), only one upsetting deformation treatment is performed.

[0100] Step (5) surface polishing, processing When the 30 mm rod was rolled, the shape of the rod was irregular and cracks appeared in many places on the rod.

[0101] Comparative Example 3

[0102] The same as Example 1, except that in step (7) the inert gas fusion thermal conductivity method (ISO 10720 potassium nitrate standard reagent method), the instrument analysis power is set to 4.5 KW.

[0103] During the measurement, although the sample can be completely melted, the nitrogen release curve has a tail and the measurement result is low.

[0104] Comparative Example 4

[0105] The same as Example 1, except that in step (7) of the neutron activation method, the weight of the gradient quality control sample to be tested is 20 mg.

[0106] When conducting the measurement, the sample weight was too small and the sample uniformity was poor, resulting in poor parallelism in the measurement results.

[0107] From the above content, it can be seen that the present invention solves the problem of the difficulty of gradient introduction of nitrogen in the field of nickel-based high-temperature alloy material preparation. It provides a set of matrix-matched high-temperature alloy gradient quality control samples for the determination of nitrogen by inert gas melting thermal conductivity method (relative method), improves the quality determination system of high-temperature alloy nitrogen, ensures the accuracy and traceability of high-temperature alloy sample nitrogen determination, and fills the gap of nickel-based high-temperature alloy sample nitrogen gradient quality control samples.

[0108] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy, characterized in that: The following steps are involved: Taking GH3536 nickel-based superalloy as the matrix, ingots with gradient nitrogen content were prepared. Ingots were named N1 to N5 in descending order according to the nitrogen content. Ingot N1 was GH3536 nickel-based superalloy. Performing homogenization treatment on the N1-N5 ingots; The ingot subjected to the homogenization treatment is subjected to two upsetting deformation treatments to obtain a rod; The bar is surface polished and processed into a specification of 30mm~ For small bars of 100 mm, the uniformity of the small bars is initially inspected at the head, middle and tail positions; The small bars that have passed the initial inspection are processed into 6.35mm alternative material; Conducting uniformity inspection and fixed value analysis on the candidate materials, wherein the fixed value analysis methods include an inert gas melting thermal conductivity method and a prompt gamma neutron activation analysis k0 standard method; When using the gradient quality control sample, the sample weight is >20 mg.

2. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The GH3536 nickel-based high-temperature alloy includes the following components in terms of mass percentage: Fe: 17%~20%, Cr: 20.5%~23%, Mo: 8%~10%, Co: 0.5%~2.5%, W: 0.2%~1%, C: 0.05~0.15%, Ti≤0.15%, N≤0.04%, and Ni: balance.

3. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The steps for preparing the ingot with gradient nitrogen content are: adding high nitrogen ferrochrome into a matrix, and preparing the ingot with gradient nitrogen content by vacuum induction melting.

4. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 3, characterized in that: The gradient of the gradient nitrogen content in the ingot is: the N content of ingot N1 is 0.0005~0.003wt%, the N content of ingot N2 is 0.003~0.007wt%, the N content of ingot N3 is 0.007~0.015wt%, the N content of ingot N4 is 0.015~0.025wt%, and the N content of ingot N5 is 0.025~0.045wt%, wherein the range values ​​of the N content do not include the upper limit endpoint value.

5. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The steps of the homogenization treatment are: heating to 1160-1200° C. at 1-10° C. / min, keeping the temperature for 40-80 hours, and cooling to room temperature after the end of the heat preservation.

6. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The deformation temperatures of the two upsetting deformation treatments are both 1140-1160°C, the heating rates are both 1-5°C / min, the holding time is not less than 4h, and the single deformation amount is both 30-60%.

7. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The bar material after the two upsetting deformation treatments is 32~ 102mm round bar.

8. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: In the inert gas melting thermal conductivity method, the analysis power is 5.5 KW, the analysis time is 180 s, and the reference reagent is potassium nitrate.

9. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: The specific method of the prompt gamma neutron activation analysis k0 standard method is: the gradient quality control sample to be tested and potassium chloride are packed with carbonate, and 7×10 9 n / s 14MeV neutron beam irradiation for 10 minutes, cooling for 2 minutes respectively, measuring the analytical sensitivity ratio of nitrogen element and comparator in turn, and then using the wide energy range efficiency calibration curve to obtain the k0 value; The comparator is 36 1951KeV gamma ray of Cl.

10. The method for preparing a gradient quality control sample for nitrogen element analysis of a nickel-based high-temperature alloy according to claim 1, characterized in that: According to the wide energy range efficiency calibration curve, 36 The 1951KeV gamma rays emitted by the Cl nuclear reaction and 15 The 1884KeV gamma ray emitted by the N nuclear reaction corresponds to Substituting into equation (1), we can obtain the value of k0: （1） Substituting the k0 value into formula (2) we can calculate the nitrogen content (C x ), （2） The x's represent the parameters of the element to be measured, and the c's represent the comparator parameters. A p , counting rate per unit weight (Bq / g); A sp , counting rate per unit weight (Bq / μg); , the absolute detection efficiency of the full energy peak; C x Unit: μg / g.

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