Novel method for accurately measuring content of easily segregated elements in as-cast alloy

Abstract

The invention discloses a novel method for accurately measuring the content of easily segregated elements in an as-cast alloy, which comprises the following steps of: performing heat treatment on an as-cast sample at the aggregation phase redissolution temperature of the easily segregated elements, and testing by using an X-ray fluorescence spectrum analyzer after the easily segregated elements are uniformly diffused in an alloy matrix, so that the content of the easily segregated elements in the as-cast alloy can be accurately measured. The method is characterized by comprising the following steps that S1, according to an alloy component system, the redissolution temperature of an easily segregated element aggregation phase is obtained through simulation software or an experimental method; s2, preparing a cylindrical as-cast sample; the method has the beneficial effects that the content of the easily segregated elements in the as-cast alloy can be accurately measured through the method, the method is simple to operate and easy to master, and the method is provided for accurately measuring the content of the easily segregated elements in the as-cast alloy by X-ray fluorescence spectrum analysis equipment; and meanwhile, the method is suitable for monitoring the content of segregation-prone elements in the as-cast alloy in the large-scale production process of production enterprises, and the stability of product quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of measuring the content of elements prone to segregation in cast alloys, in particular to a new method for accurately measuring the content of elements prone to segregation in cast alloys. Background Art

[0002] X-ray fluorescence spectrometry is a common method for measuring the content of chemical elements in solid metals. The principle is to analyze the wavelength (or energy) and intensity of X-rays generated by different elements when a high-energy electron beam irradiates a sample, and use the mathematical and physical relationship between the type and content of elements and the wavelength and intensity of elements to obtain the composition and content information of elements in the sample, so as to achieve the purpose of qualitative and quantitative analysis. Since the penetration ability of high-energy electron beams is limited when irradiating metal samples, it is impossible to analyze the information of deeper elements on the surface of the metal sample, and only the element information of a certain depth layer on the surface of the metal sample (<1μm) can be analyzed. However, the size of the solid aggregate phase formed by the easily segregated elements in the cast alloy is generally>1μm, so the uneven distribution of the easily segregated elements in the cast alloy on the sample surface will lead to a decrease in the measurement accuracy of the X-ray fluorescence spectrometer. The present invention heat treats the cast sample at the re-dissolution temperature of the easily segregated element aggregate phase, and after the easily segregated elements are evenly diffused in the alloy matrix, the X-ray fluorescence spectrometer is used for testing to improve the measurement accuracy. Summary of the invention

[0003] The object of the present invention is to provide a new method for accurately measuring the content of segregation-prone elements in cast alloys to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a new method for accurately measuring the content of easily segregated elements in a cast alloy, wherein the cast sample is heat treated at the dissolution temperature of the easily segregated element aggregate phase, and after the easily segregated elements are uniformly diffused in the alloy matrix, an X-ray fluorescence spectrometer is used for testing, comprising the following steps:

[0005] S1. According to the alloy composition system, use simulation software or experimental methods to obtain the dissolution temperature of the aggregation phase of the easily segregated elements;

[0006] S2, preparing a cylindrical cast specimen;

[0007] S3, baking the cylindrical sample prepared in S2 at the re-dissolution temperature calculated in S1, and then cooling the material to room temperature;

[0008] S4. Use sandpaper to select one of the planes of the sample for polishing, then use X-ray fluorescence spectrometry equipment to measure the sample and output the final test results.

[0009] Preferably, the cylindrical cast specimen in S2 has a diameter of 36 mm and a thickness of 20-30 mm.

[0010] Preferably, the baking time in S3 is 1 h-5 h.

[0011] Preferably, the cooling method in S3 is water cooling or air cooling.

[0012] Preferably, the mesh number of the sandpaper in S4 is 120 meshes.

[0013] Compared with the prior art, the beneficial effects of the present invention are: through this method, the content of easily segregated elements in cast alloys can be accurately measured; the method is simple to operate and easy to master, and provides a method for X-ray fluorescence spectrometry equipment to accurately measure the content of easily segregated elements in cast alloys; and at the same time, it is suitable for production enterprises to monitor the content of easily segregated elements in cast alloys during large-scale production to ensure the stability of product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a step diagram of Example 1 of the present invention;

[0015] Figure 2 This is the metallographic structure comparison of the GH4169 as-cast sample and the sample after 1160℃ heat treatment in Appendix B of the present invention;

[0016] Figure 3 This is the metallographic structure comparison of the GH4169G cast sample in Appendix C of the present invention and the sample after heat treatment at 1140℃. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-3 , the present invention provides a technical solution:

[0019] Case 1: Accurate measurement method of Nb, an element that is prone to segregation, in GH4169.

[0020] S1. According to the composition system of GH4169 alloy, the heat treatment experiment of GH4169 cast sample is designed. Appendix B is the metallographic photos of GH4169 cast sample and after heat treatment at 1160℃. It can be seen that the laves phase has been completely dissolved after heat treatment at 1160℃ for 1h. Therefore, the dissolution temperature of the laves phase, which is the aggregation phase of the easily segregated element Nb, is 1160℃.

[0021] S2. Prepare GH4169 cylindrical cast specimens with a diameter of 36 mm and a thickness of 20 to 30 mm.

[0022] S3. Bake the GH4169 cylindrical sample prepared in the second step at the re-dissolution temperature calculated in the first step for at least 1 h to 5 h, and then water-cool or air-cool the material to room temperature.

[0023] S4. Use 120-grit sandpaper to select one plane of the sample for polishing, then use X-ray fluorescence spectrometry equipment to measure the sample and output the final test results.

[0024] The Nb element content in the tested sample was 5.25%, which deviated from the Nb element ratio in the alloy (the ratio was 5.23%) by 0.02%, which was within the allowable error of the instrument. The result of measuring the unheat-treated cast sample by X-ray fluorescence spectrometer was 5.50%, which deviated from the ratio by 0.27%, which was much larger than the allowable error of the instrument.

[0025] Case 2: Accurate measurement method of P and Nb elements in GH4169G.

[0026] S1. According to the GH4169G alloy composition system, the heat treatment experiment of GH4169G cast sample is designed. Appendix C is the metallographic photos of GH4169G cast sample and after heat treatment at 1140℃. It can be seen that after heat treatment at 1140℃ for 1h, the laves phase of Nb and P elements has been completely dissolved. Therefore, the dissolution temperature of the laves phase of Nb and P elements that are easy to segregate is 1140℃.

[0027] S2. Prepare GH4169G cylindrical cast specimens with a diameter of 36 mm and a thickness of 20 to 30 mm.

[0028] S3. The GH4169G cylindrical sample prepared in the second step is baked at the laves phase re-dissolution temperature obtained by the first step experimental method for 1 hour, and then the material is water-cooled or air-cooled to room temperature.

[0029] S4. Use 120-grit sandpaper to select one plane of the sample for polishing, then use X-ray fluorescence spectrometry equipment to measure the sample and output the final test results.

[0030] The P content of the sample was 0.022%, which was 0.001% different from the P ratio of the alloy (0.021%), within the instrument's allowable error range. The result of the unheat-treated cast sample measured by X-ray fluorescence spectrometer was 0.035%, which was 0.014% different from the ratio, far greater than the instrument's allowable error.

[0031] Case 3: Accurate measurement of Ti element in GH4720Li

[0032] S1. According to the composition system of GH4720Li alloy, the decomposition temperature of the eutectic phase of Ti, an element that is easy to segregate, is obtained by experimental method, which is 1150℃.

[0033] S2. Prepare GH4720Li cylindrical cast specimens with a diameter of 36 mm and a thickness of 20 to 30 mm.

[0034] S3. The GH4720Li cylindrical sample prepared in the second step is baked at the re-dissolution temperature obtained by the first step experimental method for 1.5 h, and then the material is water-cooled or air-cooled to room temperature.

[0035] S4. Use 120-grit sandpaper to select one plane of the sample for polishing, then use X-ray fluorescence spectrometry equipment to measure the sample and output the final test results.

[0036] The Ti content in the sample was tested to be 5.15%, which deviated from the Ti ratio in the alloy by 0.02%, and was within the allowable error range of the instrument.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new method for accurately measuring the content of segregation-prone elements in cast alloys, wherein the cast sample is heat treated at the dissolution temperature of the segregation-prone element aggregation phase, and after the segregation-prone elements are uniformly diffused in the alloy matrix, an X-ray fluorescence spectrometer is used for testing, characterized in that: The following steps are involved: S1. According to the alloy composition system, use simulation software or experimental methods to obtain the dissolution temperature of the aggregation phase of the easily segregated elements; S2, preparing a cylindrical cast specimen; S3, baking the cylindrical sample prepared in S2 at the re-dissolution temperature calculated in S1, and then cooling the material to room temperature; S4. Use sandpaper to select one of the planes of the sample for polishing, then use X-ray fluorescence spectrometry equipment to measure the sample and output the final test results.

2. A new method for accurately measuring the content of segregation-prone elements in cast alloys according to claim 1, characterized in that: The cylindrical cast specimen in S2 has a diameter of 36 mm and a thickness of 20-30 mm.

3. A new method for accurately measuring the content of segregation-prone elements in cast alloys according to claim 1, characterized in that: The baking time in S3 is 1 h to 5 h.

4. A new method for accurately measuring the content of segregation-prone elements in cast alloys according to claim 1, characterized in that: The cooling method in S3 is water cooling or air cooling.

5. A new method for accurately measuring the content of segregation-prone elements in cast alloys according to claim 1, characterized in that: The mesh number of the sandpaper in S4 is 120 meshes.

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