Preparation Method of Gradient Quality Control Samples for Trace Element Analysis of Superalloys

Abstract

The invention discloses a preparation method of a gradient quality control sample for trace element analysis of superalloys, belonging to the technical fields of material preparation and element analysis. Trace elements are added to the GH4169 alloy in the invention, and then a gradient quality control sample for trace element analysis of superalloys is prepared through high-temperature multi-stage homogenization treatment, hot isostatic pressing treatment, rolling, uniformity inspection, certified value analysis and uncertainty evaluation. It provides a basis for the accurate and rapid analysis of trace elements in superalloys by the GDMS method. After calibrating the RSF with a reference material or quality control sample matching the superalloy matrix, the accuracy of the analysis data can be improved.

Description

Technical Field

[0001] The technical field relates to material preparation and elemental analysis, and particularly to a preparation method for a gradient quality control sample for trace element analysis of superalloys at high temperature. Background Art

[0002] Nickel-based superalloys are used to manufacture hot-end components of aeroengines and gas turbines due to their excellent comprehensive properties such as high-temperature strength and corrosion resistance. The performance of superalloy products is usually closely related to the alloy composition. In addition to the main elements such as tungsten, molybdenum, aluminum, titanium, and niobium, their service life is also affected by various trace elements such as lead, bismuth, tellurium, thallium, silver, tin, selenium, and arsenic. For example, in the GH4169 nickel-based superalloy, which is the most widely used and has the largest consumption in aeroengines, more than 20 trace elements need to be controlled, and the content of multiple trace components is required to be controlled below 0.00003%. This not only places extremely high requirements on the purity of the material but also poses a severe challenge to composition analysis.

[0003] The testing of trace elements in superalloys usually adopts the traditional wet method combined with instrumental analysis methods, such as atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), etc. These methods require pretreatment operations such as dissolving the sample. However, due to the complex matrix of superalloys, it is difficult to dissolve them, and the wasted time and a large amount of reagents also lead to high testing costs and low efficiency, ultimately resulting in high analysis costs for trace elements. Glow discharge mass spectrometry (GDMS) analysis technology can directly and rapidly measure solid samples, with an element detection limit reaching 10 -9 order of magnitude, and can simultaneously determine multiple elements, and has been widely used in the analysis and detection of high-purity materials, metal materials, and semiconductor materials. Therefore, the GDMS analysis method is the most effective solution for the rapid, accurate, and low-cost analysis of trace elements in nickel-based superalloys.

[0004] The quantitative determination of GDMS technology uses the relative method, and the relative sensitivity factor (RSF) is obtained through a reference material matching the matrix, and the analysis accuracy reaches within 10%, reaching the analysis accuracy of the conventional wet method. However, the lack of reference materials for GDMS technology analysis limits the application of the GDMS method in the field of superalloy composition analysis. The realization of a gradient uniform distribution of dozens of trace elements poses high requirements for the sample preparation process and quantitative analysis. Based on the requirements of trace element analysis of various superalloys, it is urgent to develop a set of nickel-based superalloy trace element gradient bulk quality control samples. Summary of the Invention

[0005] The present invention provides a method for preparing a gradient quality control sample for trace element analysis of superalloys, which is used to solve the problem of the shortage of trace element superalloy quality control samples suitable for solid sampling analysis in China caused by unreasonable design of the composition gradient of the quality control sample, high smelting difficulty, and time-consuming and costly methods for detecting the composition uniformity.

[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 trace element analysis of superalloys, comprising the following steps:

[0008] Based on the actual values and standard ranges of trace elements in common grade wrought superalloys, 34 trace elements are selected, and the upper and lower limits of each trace element are determined as the design reference values for the upper and lower limits of the target composition of the gradient quality control sample. The designed composition gradient spans no less than two orders of magnitude; after determining the target composition and its gradient, the expected uncertainty of the gradient quality control sample is determined based on the expanded uncertainty of the similar content of the corresponding elements in common grade wrought superalloys; a GH4169 alloy bar with a weight of not less than 800 kg is used as the raw material for preparing the gradient quality control sample, and the 34 trace elements are Ag (silver), As (arsenic), Au (gold), B (boron), Ba (barium), Bi (bismuth), Ca (calcium), Cd (cadmium), Ce (cerium), Co (cobalt), Cu (copper), Ga (gallium), Ge (germanium), Hf (hafnium), In (indium), La (lanthanum), Mg (magnesium), Mn (manganese), P (phosphorus), Pb (lead), Pd (palladium), Pt (platinum), Ru (ruthenium), S (sulfur), Sb (antimony), Sc (scandium), Se (selenium), Si (silicon), Sn (tin), Ta (tantalum), Te (tellurium), Tl (thallium), Y (yttrium), and Zn (zinc);

[0009] According to the target composition of the gradient quality control sample, on the basis of the raw material composition, elemental substances or compounds of the trace element components are added by vacuum induction melting.

[0010] After vacuum induction melting, an ingot is obtained. The ingot is subjected to high-temperature multi-stage homogenization treatment, and the high-temperature multi-stage homogenization treatment is as follows: First, heat it at a rate of 5-10 °C / min to 1120-1140 °C and hold for 5-15 h. Then, heat it at a rate of 1-5 °C / min to 1150-1170 °C and hold for 20-40 h. Finally, heat it at a rate of 1-5 °C / min to 1180-1200 °C and hold for 40-70 h. Since the matrix of the gradient quality control sample is GH4169 alloy, the Nb content in the alloy is relatively high and prone to segregation. Secondly, the alloy also contains a large number of trace elements, and the contents of various trace elements exceed the limit range of the alloy, and the diffusion rate of some elements with relatively high atomic numbers is slow. However, the quality control sample has high requirements for the uniformity and consistency of the composition. Therefore, in the present invention, the high-temperature multi-stage homogenization treatment method is adopted to reduce the segregation of Nb element and the diffusion and homogenization of high-content trace elements. Slow heating and holding between 1120 °C and 1170 °C are to eliminate the low-melting Laves phase and reduce the influence of Nb element segregation on the chemical composition uniformity of the alloy; long-term holding at 1180-1200 °C is for the trace elements to achieve uniform distribution;

[0011] The ingot after the high-temperature multi-stage homogenization treatment is subjected to hot isostatic pressing treatment;

[0012] The ingot after the hot isostatic pressing treatment is prepared into a round bar by cogging. The surface of the round bar is processed, and the composition of the head and tail of the round bar after the surface processing is detected to ensure the successful addition of the added trace elements, and the content of the trace elements shows a designed gradient distribution. When the success rate of the added trace elements is not less than 85%, the gradient quality control sample is processed, uniformity inspection, value determination analysis and uncertainty evaluation are carried out;

[0013] The feasibility of the gradient quality control sample is evaluated by means of comparison and verification. The content of the comparison and verification includes linear investigation and consistency investigation. When the correlation coefficients of the linear investigation and the consistency investigation are both not less than 0.99, the gradient quality control sample for trace element analysis of the superalloy is prepared.

[0014] The common grades of the wrought superalloy are GH4169 alloy, GH4169D alloy, GH4720Li alloy, GH4065A alloy, GH4738 alloy, FGH4096 alloy, DD405 alloy and DD406 alloy.

[0015] The vacuum induction melting includes: processing the GH4169 alloy bars into massive raw materials with a weight of not less than 100 kg, adding the massive raw materials into a vacuum induction melting furnace, evacuating the vacuum induction melting furnace to a vacuum degree of not higher than 5 Pa, heating the vacuum induction melting furnace until all the massive raw materials are melted, introducing argon gas, adding elemental substances or compounds of the trace element components according to the target components of the gradient quality control samples, with a refining time of not more than 30 min, taking out of the furnace for pouring to obtain an ingot.

[0016] During the hot isostatic pressing treatment: the heating rate is 0.1 - 5 °C / min, the temperature is 1150 - 1200 °C, the pressure is 140 MPa - 180 MPa, heat preservation and pressure maintenance are for 2 - 4 h, and it is cooled with the furnace while filling argon gas.

[0017] The steps of preparing a round bar by blooming the ingot after the hot isostatic pressing treatment are as follows: heating the ingot to 1060 - 1100 °C at a rate of 2 - 5 °C / min, after heat preservation for 4 h, upsetting by 20 - 30%; then returning to the furnace for heat preservation for 4 h, and performing unidirectional drawing with a deformation amount of 20 - 40%; after returning to the furnace for heat preservation again, the heat preservation temperature is 1040 - 1080 °C, and unidirectional drawing is continued with a deformation amount of 20 - 40%. By repeating the unidirectional drawing process 1 - 3 times, a 32 - mm round bar is obtained.

[0018] The certified value analysis is carried out by combining the certified values of multiple laboratories with multiple methods. According to JJF 1343 - 2022 "Certification and Evaluation of Homogeneity and Stability of Reference Materials", the mean value of the mean values of the certified value data of the characteristic quantities of each laboratory is used as the certified value of the characteristic quantity.

[0019] The uncertainty is the combined standard uncertainty, and the combined standard uncertainty is calculated with reference to JJF 1343 - 2012 "General Principles and Statistical Principles for the Certification of Reference Materials", and the specific details are shown in formula (1):

[0020] (1)

[0021] In formula (1), is the combined standard uncertainty, is the standard uncertainty brought by the certification process, is the standard uncertainty caused by the between - bottle inhomogeneity, is the standard uncertainty caused by the long - term instability, is the standard uncertainty caused by the short - term instability;

[0022] The standard uncertainty brought by the certification process consists of the type A evaluation component (i.e., the type A uncertainty) and the type B evaluation component (i.e., Type B uncertainty) is synthesized, as shown in formula (2):

[0023] (2)

[0024] Type B uncertainty involves the influence of non-statistical factors in the measurement process, such as the calibration of instruments, changes in the measurement environment, etc. In the case of co-determination by multiple accurate methods, these non-statistical factors have been reflected in the observed values of each laboratory. Therefore, Type B uncertainty is not calculated separately during the value determination process. During the preparation process of the gradient quality control sample for trace element analysis of superalloys in the present invention, a normality test was performed on the laboratory value determination data, and the test data that caused the non-normal distribution in the normality test was excluded. When the overall normality of the value determination data is good, the Type A uncertainty is calculated by formula (3):

[0025] (3)

[0026] In formula (3), is the standard deviation during the value determination process, is the number of data groups;

[0027] The rounding of the certified value data of the gradient quality control sample follows the principle of only rounding up and not rounding down according to the rounding rules of uncertainty in GB 8170-2008 Rules for Rounding off of Numerical Values and Presentation and Judgment of Limit Values.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] (1) The present invention successfully prepared a gradient quality control sample for trace element analysis of superalloys. 31 elements were successfully added and distributed in a gradient, meeting the requirements of the target composition design, providing a reference for the subsequent preparation of superalloys and other quality control samples. The route of the present invention is simple and the cost is low, enabling large-scale manufacturing of quality control samples and effectively reducing the cost of component analysis.

[0030] (2) The gradient quality control sample for trace element analysis of superalloys prepared by the present invention provides a basis for the accurate and rapid analysis of trace elements in superalloys by the GDMS method. After calibrating the RSF with a reference material or quality control sample matching the superalloy matrix in the GDMS analysis method, the accuracy of the analysis data can be improved. The present invention solves the problem of the lack of superalloy reference materials for the GDMS analysis method in China, fills the domestic gap in this field, and has great significance in the production control of superalloy products, finished product analysis, and metrology of testing equipment.

[0031] (3) The present invention lays a foundation for the application of rapid analysis technology for trace elements in superalloys. By combining gradient quality control samples with the GDMS method, the analysis cycle of traditional chemical wet methods and instrumental analysis methods can be shortened from 15 working days to within 1 working day, and the cost can be reduced by about 90%. It provides technical support for the low-cost, rapid, and accurate analysis of superalloy materials, serves the preparation of high-end equipment in our country, and ensures its service safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0033] Figure 1 It is a schematic diagram of the preparation process of the quality control sample for trace element analysis of superalloys in the present invention;

[0034] Figure 2 It is a physical diagram of the ingot after rolling in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0035] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0036] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0037] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can 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 related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0038] Without departing from the scope or spirit of the present invention, various modifications and variations to the specific embodiments of the description of the present invention will be apparent to those skilled in the art. Other embodiments obtained from the description of the present invention will be apparent to those skilled in the art. The description and examples of the present invention are merely exemplary.

[0039] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0040] An embodiment of the present invention provides a method for preparing a gradient quality control sample for trace element analysis of superalloys, comprising the following steps:

[0041] (1) Composition gradient design of the gradient quality control sample for trace element analysis of superalloys: Based on the actual values and standard ranges of trace elements in the commonly used grades of wrought superalloys with the largest consumption in China (GH4169 alloy, GH4169D alloy, GH4720Li alloy, GH4065A alloy, GH4738 alloy, FGH4096 alloy, DD405 alloy, and DD406 alloy), 34 trace elements were selected as the objects. The 34 trace elements are Ag, As, Au, B, Ba, Bi, Ca, Cd, Ce, Co, Cu, Ga, Ge, Hf, In, La, Mg, Mn, P, Pb, Pd, Pt, Ru, S, Sb, Sc, Se, Si, Sn, Ta, Te, Tl, Y, and Zn. Following the principle of meeting a wider analysis requirement with fewer sample points, attempting to cover the composition requirements of superalloy grades with one set or fewer sample points to improve the comprehensiveness, the upper and lower limits of each trace element were determined as the design reference values for the upper and lower limits of the target composition of the gradient quality control sample. The designed composition gradient spans no less than two orders of magnitude; after determining the target composition and its gradient, the expected uncertainty of the gradient quality control sample was determined based on the expanded uncertainty of the similar content of the corresponding elements in steel and alloys; Considering high purity, low cost, and output, the GH4169 alloy prepared by triple smelting was selected as the master alloy. After testing the composition of 50 furnace batches of GH4169 alloy, it was finally determined that GH4169 alloy bars with a weight of not less than 800 kg were used as the raw materials for preparing the gradient quality control sample;

[0042] (2) According to the target composition of the gradient quality control sample, on the basis of the raw material composition of GH4169 alloy, the elemental single metal or compound of the trace element composition is added by vacuum induction melting, that is, after the raw materials and the elemental single metal or compound to be added are prepared, the vacuum induction melting method is used for remelting to achieve the preparation of the target alloy ingot, specifically: first, the GH4169 alloy bar is cut into block raw materials with a weight of not less than 100kg (preferably the weight of the block raw materials is 100kg~500kg), and then added into a vacuum induction melting furnace, evacuated to a vacuum degree of not more than 5Pa, heated to between 1300℃ and 1400℃ to ensure that the alloy is completely melted, and then argon (Ar gas) not higher than 0.1MPa is introduced, and the target trace element is added to make the component ratio weight reach the alloy target value, the refining time does not exceed 30min, and then the ingot containing different trace elements is cast out of the furnace;

[0043] (3) The ingots containing different trace elements were subjected to homogenization treatment: the temperature was raised to 1120~1140℃ at a rate of 5~10℃ / min, and kept at this temperature for 5~15h, then the temperature was raised to 1150℃~1170℃ at a rate of 1~5℃ / min, and kept at this temperature for 20~40h, and finally the temperature was raised to 1180~1200℃ at a rate of 1~5℃ / min, and kept at this temperature for 40~70h. Since the matrix of the gradient quality control sample is GH4169 alloy, the Nb content in the alloy is high and easy to segregate. Secondly, the alloy also contains a large number of trace elements, and the content of many trace elements exceeds the limit range of the alloy. In addition, the diffusion rate of some elements with relatively high atomic numbers is slow. The quality control sample has high requirements for the uniformity and consistency of the composition. The high-temperature multi-stage homogenization method is used to reduce the segregation of the Nb element and the uniform diffusion of high-content trace elements. The slow rate heating and heat preservation between 1120℃~1170℃ is to eliminate the low-melting point Laves phase and reduce the influence of Nb element segregation on the uniformity of the chemical composition of the alloy; the long-term heat preservation at 1180~1200℃ is to achieve uniform distribution of trace elements.

[0044] (4) The ingot after homogenization treatment is subjected to hot isostatic pressing treatment: heating rate 0.1~5℃ / min, temperature 1150~1200℃, pressure 140MPa~180Mpa, heat and pressure maintenance for 2~4h, and cooling with Ar gas. The ingot after vacuum induction melting has shrinkage holes at the head and local microcracks inside. Some trace elements are easy to segregate at the grain boundary, resulting in grain boundary weakening, and high-temperature plasticity is seriously reduced. Direct thermal deformation will cause cracking. Therefore, hot isostatic pressing treatment effectively reduces the microcracks inside the ingot and further improves the thermoplasticity.

[0045] (5) Prepare it into a round bar by cogging. Heat the ingot after hot isostatic pressing to 1060 - 1100 °C at a rate of 2 - 5 °C / min. After holding for 4 h, upset it by 20 - 30%; then return it to the furnace and hold for 4 h, and perform unidirectional drawing with a deformation amount of 20% - 40%; after returning to the furnace and holding again, the holding temperature is 1040 - 1080 °C, and continue unidirectional drawing with a deformation amount of 20% - 40%. By repeating the unidirectional drawing process 1 - 3 times, obtain a 32 - mm round bar;

[0046] (6) Perform surface processing on the 32 - mm round bar to remove the surface black skin and expose the metallic luster, obtaining a 30 - mm round bar for subsequent processing of gradient quality control samples;

[0047] (7) Select the head and tail of the rolled small - sized bar (i.e., the 30 - mm round bar) for composition detection to ensure the successful addition of various trace elements and the content shows a designed gradient distribution. When the success rate of the added trace elements is not less than 85%, perform subsequent processing of gradient quality control samples and homogeneity inspection;

[0048] (8) The rolled small - sized bar is sequentially wire - cut according to a length of 30 mm to obtain 30 - mm × 30 - mm cylindrical samples, which are spectral quality control samples, and are sequentially labeled as 1 - 1, 1 - 2, 1 - 3, 1 - 4, 1 - 5, etc. The number in front is the code of 5 kinds of samples, arranged in ascending order of composition, and the number behind is the cutting order of a certain - composition sample. Randomly select 10 samples from each sample and machine them into chip - shaped samples, mix them thoroughly, and pack them into bottles of 50 g each. Accurately determine the values of each element composition by multiple laboratories with inspection qualifications using traditional wet methods and instrumental analysis methods;

[0049] (9) Perform homogeneity inspection. The homogeneity inspection work of this batch of quality control samples is sampled according to the provisions of JJF1342 - 2022 "General Requirements for Standard Substance Research and Development (Production) Institutions"; data processing is carried out according to the requirements of JJF 1343 - 2012 "General Principles and Statistical Principles for Standard Substance Value Assignment";

[0050] (10) Conduct value assignment analysis and uncertainty evaluation on the quality control samples:

[0051] In this invention, there are many value - assigned elements in the quality control samples, the element content is low, and the value - assignment is difficult. Multi - laboratory and multi - method combined value - assignment is adopted. According to JJF 1343 - 2022 "Value Assignment and Homogeneity and Stability Evaluation of Standard Substances", the mean of the mean values of the characteristic quantity value - assignment data of each laboratory is used as the certified value of the characteristic quantity.

[0052] Referring to JJF 1343-2012 "General Principles and Statistical Principles for the Determination of Standard Materials", JJF 1343-2012 "General Principles and Statistical Principles for the Determination of Standard Materials" specifies in detail the evaluation method of the uncertainty of standard materials. The specification points out that the uncertainty of standard materials consists of three parts: the uncertainty introduced by uniformity, the uncertainty introduced by stability, and the uncertainty caused by the determination process. The combined standard uncertainty is obtained by calculating the square root of the sum of the squares of these three parts, and finally multiplying it by the inclusion factor k to obtain the expanded uncertainty, where k is usually 2, corresponding to a 95% confidence probability of 2. The basic calculation formula for the combined standard uncertainty is detailed in formula (1):

[0053] (1)

[0054] In formula (1), is the combined standard uncertainty, The standard uncertainty brought by the determination process, is the standard uncertainty due to the inhomogeneity between bottles, is the standard uncertainty due to long-term instability, is the standard uncertainty due to short-term instability;

[0055] Standard uncertainty caused by the determination process A-rated weight (i.e., Type A uncertainty) and Type B assessment components (i.e. Class B uncertainty) synthesis. The assessment of Class B and Class A uncertainties comes from JJF 1059.1-2012 "Evaluation and Expression of Uncertainty in Measurement", referred to as the GUM method, which can also be called the Bottom-up method. It is the measurement uncertainty assessment method currently used in various industries internationally. Class B uncertainty refers to the uncertainty component evaluated by non-statistical methods, which is usually evaluated based on experience, information or assumed probability distribution. First, it is necessary to identify the source of uncertainty, which includes factors such as the metrological performance of the measuring instrument, the influence of environmental conditions, and the accuracy of the measurement model. Based on relevant information or experience, the possible value range of the measured value is judged, and the probability distribution of the measured value is assumed. On this basis, the inclusion factor k is determined according to the probability distribution and the required inclusion probability p, thereby calculating the Class B standard uncertainty. The calculation method of is shown in formula (2):

[0056] (2)

[0057] Type B uncertainty involves the influence of non-statistical factors in the measurement process, such as instrument calibration, changes in the measurement environment, etc. In the case of co-determination by multiple accurate methods, these non-statistical factors have been reflected in the observed values of each laboratory, so type B uncertainty is not calculated separately during the value determination process. During the preparation of the gradient quality control samples for the analysis of trace elements in superalloys of the present invention, a normality test was performed on the laboratory value determination data, and the test data that caused the non-normal distribution in the normality test was excluded. When the overall normality of the value determination data is good, type A uncertainty is calculated by formula (3):

[0058] (3)

[0059] In formula (3), is the standard deviation during the value determination process, is the number of data groups.

[0060] For the rounding of the standard value data of trace elements in the gradient quality control samples for the analysis of trace elements in superalloys, the rounding rule of uncertainty in GB8170-2008 Rules for Rounding off of Numerical Values and Presentation and Judgment of Limit Values is adopted, and the principle of only rounding up and not rounding down is followed.

[0061] (11) The feasibility of the gradient trace element quality control samples for superalloys is evaluated by means of comparison verification (including linearity investigation and consistency investigation). When the correlation coefficients of both the linearity investigation and the consistency investigation are not less than 0.99, the above-mentioned gradient quality control samples have passed the finished product uniformity, homogeneity test and comparison verification in sequence, and the preparation of the gradient quality control samples is successful.

[0062] In the following embodiments of the present invention, 34 trace elements are added in the following form: silver, arsenic, gold, barium, bismuth, cadmium, gallium, germanium, hafnium, indium, lead, palladium, platinum, ruthenium, antimony, scandium, selenium, tin, tellurium, thallium, zinc, copper, cobalt and tantalum are added in the form of elemental metals; silicon, chromium, manganese, boron, phosphorus and sulfur are added in the form of ferroalloys of ferrosilicon, ferrochromium nitride, ferromanganese, ferroboron, ferrophosphorus and ferrosulfur respectively; calcium, lanthanum, cerium and yttrium are added in the form of calcium oxide, lanthanum oxide, cerium oxide and yttrium oxide respectively.

[0063] In the following embodiments of the present invention, the reference materials GBW01636 to GBW01640 are all purchased from National Research NanoScience & Technology Co., Ltd.

[0064] In the following embodiments of the present invention, the information value refers to those characteristic quantity values that have certain use value for the users of reference materials, but there is insufficient information in the evaluation of uncertainty for these quantity values. Information values are usually not regarded as traceable or strictly measured quantity values, but are more provided to users as reference information to help users understand the matrix composition of reference materials or judge their applicability.

[0065] It should be noted that the parts not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0066] The technical solution of the present invention will be further described below through embodiments.

[0067] Embodiment 1

[0068] Referring to the standard regulations of other common grades of wrought superalloys (GH4169 alloy, GH4169D alloy, GH4720Li alloy, GH4065A alloy, GH4738 alloy, FGH4096 alloy, DD405 alloy and DD406 alloy), the composition points are designed. For example, the composition requirement of trace element Ag in wrought and powder superalloys is ≤0.0005%, and the composition requirement of single crystal superalloys is <0.0001%. Therefore, the Ag composition is designed as 0.00001%, 0.0005%, 0.0001%, 0.0002%, and the expected uncertainties are 0.00001%, 0.00003%, 0.00005%, 0.00007% respectively; the composition requirement of As in wrought superalloys is ≤0.0025%, and the composition requirement of single crystal superalloys is ≤0.001%. The composition is designed as 0.0007%, 0.0010%, 0.0020%, 0.0040%, and the expected uncertainties are 0.0003%, 0.0003%, 0.0004%, 0.0007% respectively; the composition requirement of Au in single crystal superalloys is <0.000005%. The composition is designed as 0.00005%, 0.0001%, 0.0002%, 0.0005%, and the expected uncertainties are 0.00003%, 0.00005%, 0.00008%, 0.0002%; the composition requirement of La in single crystal superalloys is 0.00007%. The composition is designed as 0.00001%, 0.00005%, 0.0001%, 0.0002% respectively, and the expected uncertainties are 0.00001%, 0.00003%, 0.00005%, 0.00007%; the composition requirement of Ce in single crystal superalloys is <0.0001%. The composition is designed as 0.00001%, 0.00005%, 0.0001%, 0.0002%, and the expected uncertainties are 0.00001%, 0.00003%, 0.00005%, 0.00007% respectively; matrix elements such as Cu in wrought superalloys have a composition requirement of ≤0.3%, and the composition requirement of single crystal superalloys is ≤0.1%. The composition is designed as 0.0039%, 0.010%, 0.020%, 0.050%, and the expected uncertainties are 0.001%, 0.002%, 0.004%, 0.005%, etc. The target values, composition gradient designs and uncertainties of 34 trace elements in 5 samples are shown in Tables 1 to 2. The sample numbered 1 is the GH4169 alloy without adding any additional elements, so it is not shown in Tables 1 to 2. The samples numbered 2 to 4 are gradient quality control samples for trace element analysis of the high-temperature alloy of the present invention with different gradients.

[0069] Table 1 Composition Design of Reference Materials (mass fraction (×10 -2 ))

[0070]

[0071] Table 2 Design of standard material composition (mass fraction (×10 -2 )

[0072]

[0073] (2) Cut GH4169 alloy bars weighing not less than 800 kg into blocks weighing 120 kg and add them into a vacuum induction melting furnace as raw materials. The vacuum induction melting furnace is evacuated to less than 5 Pa and heated to 1340 ° C to ensure that the alloy is completely melted. Ar gas is introduced to 0.06 MPa, and target trace elements (single substance or compound) are added to make the component ratio weight reach the target value of the alloy. The alloy is fully heated and stirred, and poured after 20 minutes of refining. After the pouring is completed, wait for 20 minutes before taking it out of the furnace to obtain alloys containing different trace elements. 200mm ingot.

[0074] (3) The temperature was raised to 1130°C at a rate of 10°C / min, and kept at this temperature for 10 hours. Then, the temperature was raised to 1160°C at a rate of 5°C / min, and kept at this temperature for 30 hours. Finally, the temperature was raised to 1190°C at a rate of 2°C / min, and kept at this temperature for 50 hours. After being taken out of the furnace, the ingot was further subjected to hot isostatic pressing treatment at a heating rate of 2°C / min, and maintained at 1190°C and 150MPa for 3 hours. The ingot was cooled by cooling with Ar gas, and then air-cooled after being taken out of the furnace.

[0075] (4) The ingot after hot isostatic pressing was heated to 1080°C at a rate of 3°C / min, kept at this temperature for 4 hours, and then upset by 25%. Then, the ingot was returned to the furnace for keeping at this temperature for 4 hours, and then unidirectionally stretched with a deformation of 30%. After being returned to the furnace for keeping at this temperature again, the ingot was kept at this temperature at 1060°C, and then unidirectionally stretched with a deformation of 35%. By repeating the unidirectional stretching process twice, the ingot was obtained. 32mm round rod, the round rod is polished to remove the black skin on the surface and the metallic luster is visible, 30mm round rod.

[0076] (5) Take one rolled sample each ( 30mm round bars), finished product inspection was carried out using the GDMS method, and the results are shown in Tables 3 and 4.

[0077] Table 3 Finished product inspection (mass fraction (×10 -2 )

[0078]

[0079] Table 4 Finished product inspection (quality score (×10 -2 )

[0080]

[0081] The results in Table 3 to Table 4 show that the Ba element could not be successfully added, the Cd and Sc elements were only added at high points, other elements basically met the addition requirements, the success rate of the target elements added was 91%, and the success rate exceeded 85%, proving that the preparation process of the present invention is reasonable and feasible.

[0082] (6)Samples were taken at intervals of 20 cm for 5 kinds of samples, and 12 block samples were obtained respectively. The measurements were carried out in the following order (all were tested 3 times). Repeated measurement 1: 1-3-5-7-9-11-2-4-6-8-10-12; Repeated measurement 2: 12-11-10-9-8-7-6-5-4-3-2-1; Repeated measurement 3: 2-4-6-8-10-12--1-3-5-7-9-11.

[0083] The homogeneity study was carried out on 34 trace elements by GDMS method. A complete GDMS analysis method was established by optimizing the glow discharge conditions (discharge current 40 mA, discharge gas flow 450 mL / min, pre-sputtering time 10 min), studying isotope interference, correcting the RSF factor, etc., and the homogeneity detection data were obtained using the optimized method.

[0084] For the homogeneity results, the F statistic of the comparative variance analysis was used and compared with the F critical value. The homogeneity test results showed that the certified elements of the quality control samples had good homogeneity (the F statistic was less than the F critical value), meeting the requirements of the quality control samples for homogeneity.

[0085] (7)Certification was carried out jointly by 10 laboratories with detection capabilities and qualifications. The trace element certification methods were ICP-MS method and ICP-AES method. After performing normal distribution test, outlier test and equal precision test on the certification data in turn, valid data were obtained.

[0086] (8)Determine the uncertainty of the quality control samples. During the development process of the gradient quality control samples for the analysis of trace elements in superalloys: Multiple laboratories were used for collaborative certification, and two or more methods were used for the certification of each element, so the type B uncertainty was no longer considered. is the standard uncertainty caused by the non-uniformity between bottles. Among the uncertainties caused by homogeneity, it includes the uncertainty between units and the uncertainty within units. In the present invention, when the F value > 1, is the uncertainty between units s bb ; when F < 1, is estimated from the variance of the non-uniformity within the unit. In the stability study, the chemical properties of the superalloy are very stable, so the influence brought by stability can be ignored. The expanded uncertainty U is calculated according to where For the coverage factor, when the confidence probability is 95%, k = 2 is taken.

[0087] (9) After the gradient quality control samples passed through the component design, sample development, finished product inspection, homogeneity inspection, and comparison test in sequence, it was proved that their development was successful. The certified values (X) and expanded uncertainties (U) of the gradient quality control samples for trace element analysis of superalloys are shown in Tables 5 to 6.

[0088] Table 5 Certified values and expanded uncertainties of gradient quality control samples for trace element analysis of superalloys (mass fraction (×10 -6 ))

[0089]

[0090] Table 6 Certified values and expanded uncertainties of gradient quality control samples for trace element analysis of superalloys (mass fraction (×10 -6 ))

[0091]

[0092] Note: In Tables 5 and 6, "X" is the certified value, "U" is the expanded uncertainty ( = 2), the values in "()" are reference values, and the values with "#" are information values.

[0093] Example 2

[0094] Same as Example 1, the difference is only that in step (6), in the homogeneity study, in addition to performing the F - statistic test, the total standard deviation S and the inhomogeneity variance S 2 bb were also examined to see if they meet the actual needs, and a complementary homogeneity evaluation of the simple F - test was carried out. The specific method is as follows:

[0095] (1) Comparison of the uncertainty related to the assigned value, with a smaller standard deviation between and / or within units, such as ;

[0096] (2) Allow for the inhomogeneity of the material, calculate the combined standard uncertainty of the standard value, and confirm that it is acceptable for the intended use;

[0097] (3) For reference materials for which the combined standard uncertainty is not calculated, such as quality control reference materials, compare with the typical inter - laboratory reproducibility standard deviation in the application field. The standard deviation between units is small enough. Ideally, ;

[0098] The uniformity test results of other methods show that the trace elements of the gradient quality control sample of the present invention still have good uniformity and meet the actual needs.

[0099] Example 3

[0100] The same as Example 1, except that, in step (6), in order to save time, when using glow mass spectrometry to detect the uniformity of the sample, the pre-sputtering time is set to 5 minutes, and the other conditions remain the same.

[0101] The experimental results show that within 5 to 10 minutes of the start of discharge, the intensity of the interfering element Ca is unstable and shows a trend from high to low, which cannot meet the normal test requirements. However, after 10 minutes, the intensity of Ca tends to be stable, indicating that the pollution caused by it can be completely removed at least after 10 minutes. At this time, the strength of the matrix Ni also changes slowly, which meets the test requirements.

[0102] GDMS was used to fit the 30 trace elements and 5 content level gradients of the gradient quality control sample for trace element analysis of the high-temperature alloy prepared in this embodiment, and it was found that the fitting results were linear. The results show that the 5-point standard curve has a very good linear relationship, and the correlation coefficients are all greater than 0.995. At the same time, the gradient quality control sample for trace element analysis of the high-temperature alloy prepared in this embodiment was curve-fitted with the 16 elements of the nickel-based deformed high-temperature alloy standard material (standard sample) GBW01636~GBW01640 developed in 2002. The 10-point standard curve has a very good linear relationship, and the correlation coefficients are all greater than 0.998, indicating that the consistency of the two sets of standard materials is good. Through comparison experiments, it is proved that the present invention successfully prepared gradient quality control samples.

[0103] Comparative Example 1

[0104] The same as Example 1, except that in step (3), the hot isostatic pressing step is omitted to save time and energy consumption, and the subsequent effect is observed.

[0105] Results: The ingot of this comparative example exhibited severe cracking during the rolling process of step (4) (see Figure 2 ), it is speculated that due to the presence of shrinkage holes at the head of the vacuum induction melted ingot and local microcracks inside, some trace elements are prone to segregation at the grain boundaries, resulting in grain boundary weakening, a serious decrease in high temperature plasticity, and direct thermal deformation leading to the occurrence of cracking.

[0106] Application Example 1

[0107] Taking the gradient quality control sample prepared in Example 1 as an example, through the combination of the gradient quality control sample and the GDMS method, a relatively complete analytical method for analyzing trace impurity elements in superalloys by glow discharge mass spectrometry was established by optimizing the glow discharge conditions, studying isotope interference, and correcting the RSF factor. The stability of the same type of nickel-based superalloy composition analysis reference materials numbered GBW01636 to GBW0640 was monitored within 8 hours. The measured elements were 20 trace elements such as Ag, As, B, and Bi. The standard values of the elements showed no obvious changes. The monitoring results are shown in Tables 7 to 8. The specific method is as follows:

[0108] According to JJF 1343-2022 "Certification of Reference Materials and Evaluation of Homogeneity and Stability", if the conditions are met: Then it can be considered that the material is stable enough and the stability is proved. In the formula Represents the characteristic value of the CRM, Is the measured observed value, k is the coverage factor, and k = 2 when the confidence level is 95%. The standard uncertainty caused by the measurement, The standard uncertainty of the characteristic value.

[0109] According to the definition of expanded uncertainty: , Since Is non-negative, it can be proved that in this stability monitoring, if Holds, then Holds, and the stability is thus proved.

[0110] Table 7 Summary of Stability Monitoring Results of GBW01636 - GBW01640 in January 2022 (μg / g)

[0111]

[0112] Table 8 Summary of Stability Monitoring Results of GBW01636 - GBW01640 in January 2022 (μg / g)

[0113]

[0114] The above results show that using the GDMS method for stability monitoring shortens the analysis cycle of traditional chemical wet methods and instrumental analysis methods from 15 working days to less than 1 working day. Moreover, the GDMS method mainly relies on the same type of reference materials and detection instruments, without the need to use additional chemical reagents, reducing the detection cost by about 90% (from more than 20,000 yuan to about 2,000 yuan).

[0115] The above are only the 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 those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy, characterized in that: The following steps are involved: Based on the actual values ​​and standard ranges of trace elements in commonly used grades of deformed high-temperature alloys, 34 trace elements were screened out, and the upper and lower limits of each trace element were formulated as the design reference values ​​for the upper and lower limits of the target composition of the gradient quality control sample. The designed composition gradient spanned no less than two orders of magnitude; after determining the target composition and its gradient, the expected uncertainty of the gradient quality control sample was determined by the expanded uncertainty of the similar content of the corresponding elements in the commonly used grades of deformed high-temperature alloys; A GH4169 alloy rod weighing not less than 800 kg is used as a raw material for preparing the gradient quality control sample, and the 34 trace elements are Ag, As, Au, B, Ba, Bi, Ca, Cd, Ce, Co, Cu, Ga, Ge, Hf, In, La, Mg, Mn, P, Pb, Pd, Pt, Ru, S, Sb, Sc, Se, Si, Sn, Ta, Te, Tl, Y and Zn; According to the target composition of the gradient quality control sample, adding the elemental single substance or compound of the trace element component to the raw material composition through vacuum induction melting; After the vacuum induction melting is completed, an ingot is obtained, and the ingot is subjected to a high-temperature multi-stage homogenization treatment, wherein the high-temperature multi-stage homogenization treatment is as follows: firstly, the temperature is increased to 1120-1140°C at a rate of 5-10°C / min, and the temperature is kept for 5-15 hours, then the temperature is increased to 1150-1170°C at a rate of 1-5°C / min, and the temperature is kept for 20-40 hours, and finally, the temperature is increased to 1180-1200°C at a rate of 1-5°C / min, and the temperature is kept for 40-70 hours; Performing hot isostatic pressing on the ingot after the high-temperature multi-stage homogenization treatment; The ingot after hot isostatic pressing is prepared into a round rod by blanking, the round rod is surface processed, and the head and tail of the round rod after surface processing are tested for composition to ensure the successful addition of the added trace element and the content of the trace element presents a designed gradient distribution. When the success rate of the added trace element is not less than 85%, the gradient quality control sample is processed, uniformity tested, fixed value analyzed and uncertainty evaluated; The feasibility of the gradient quality control sample is evaluated by comparison and verification, and the content of the comparison and verification includes linearity inspection and consistency inspection. When the correlation coefficients of the linearity inspection and the consistency inspection are not less than 0.99, the gradient quality control sample for trace element analysis of the high-temperature alloy is prepared; The commonly used grades of deformed high-temperature alloys are GH4169 alloy, GH4169D alloy, GH4720Li alloy, GH4065A alloy, GH4738 alloy, FGH4096 alloy, DD405 alloy and DD406 alloy.

2. The method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy according to claim 1, characterized in that: The vacuum induction melting includes: processing the GH4169 alloy rod into a block raw material with a weight of not less than 100 kg, adding the block raw material into a vacuum induction melting furnace, evacuating the vacuum induction melting furnace to a vacuum degree not higher than 5 Pa, heating the vacuum induction melting furnace until the block raw material is completely melted, introducing argon gas, adding the element single substance or compound of the trace element component according to the target composition of the gradient quality control sample, refining time not exceeding 30 minutes, taking out of the furnace and pouring to obtain an ingot.

3. The method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy according to claim 1, characterized in that: During the hot isostatic pressing treatment, the heating rate is 0.1-5°C / min, the temperature is 1150-1200°C, the pressure is 140MPa-180MPa, the temperature and pressure are kept for 2-4h, and the furnace is cooled with argon gas.

4. The method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy according to claim 1, characterized in that: The step of preparing the round rod by opening the ingot after the hot isostatic pressing treatment is as follows: heating the ingot to 1060-1100°C at a rate of 2-5°C / min, keeping the temperature for 4 hours, and upsetting by 20-30%; then returning the ingot to the furnace for keeping the temperature for 4 hours, and unidirectionally stretching the ingot with a deformation of 20-40%; returning the ingot to the furnace for keeping the temperature again, keeping the temperature at 1040-1080°C, and continuing the unidirectional stretching with a deformation of 20-40%, and repeating the unidirectional stretching process 1-3 times to obtain the round rod. 32mm round rod.

5. The method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy according to claim 1, characterized in that: The fixed value analysis adopts multi-laboratory and multi-method joint fixed value, and according to JJF 1343-2022 "Value Determination and Uniformity and Stability Evaluation of Reference Materials", the average of the average values ​​of the fixed value data of the characteristic quantity of each laboratory is used as the certified value of the characteristic quantity.

6. The method for preparing a gradient quality control sample for trace element analysis of a high-temperature alloy according to claim 1, characterized in that: The uncertainty is the combined standard uncertainty. The calculation formula of the combined standard uncertainty is shown in formula (1): （1） In formula (1), is the combined standard uncertainty, The standard uncertainty brought by the determination process, is the standard uncertainty due to the inhomogeneity between bottles, is the standard uncertainty due to long-term instability, is the standard uncertainty due to short-term instability; The standard uncertainty caused by the determination process is A-rated weight and B-level rating Synthesis, see formula (2): （2） When the overall normality of the fixed value data is good, the type A uncertainty is calculated by formula (3): （3） In formula (3), is the standard deviation in the setting process, is the number of data sets.

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