A method for detecting boron content in steel
By optimizing sample pretreatment and spectral measurement techniques, the spectral interference and volatilization loss of boron in steel were eliminated, solving the problem of decreased detection accuracy in existing technologies and enabling accurate and rapid determination of boron content in various steel grades.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PANGANG GROUP JIANGYOU CHANGCHENG SPECIAL STEEL COMPANY LIMITED
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies suffer from spectral interference, volatilization loss, and interference from coexisting elements when detecting boron content in steel, leading to decreased detection accuracy and limited applicability.
A mixed acid dissolution method combined with perchloric acid and hydrogen peroxide treatment was used to eliminate spectral interference from phosphorus, sulfur, and carbon, as well as boron volatilization loss. Furthermore, by establishing working curves and calculating corrections for interfering elements, spectral overlap interference from coexisting elements such as tungsten, molybdenum, and cobalt was eliminated.
It improves the accuracy and reliability of boron content determination in complex matrix samples, is applicable to a variety of steel grades, and is simple, fast, and environmentally friendly to operate.
Smart Images
Figure CN122109055A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel processing technology, and in particular to a method for detecting the boron content in steel. Background Technology
[0002] In the field of steel processing technology, the boron content has a significant impact on its mechanical properties, such as hardenability. Therefore, accurate determination of the boron content in steel is crucial for material research and development and quality control. Traditional methods for detecting boron in steel mainly employ chemical wet analysis, but this method suffers from drawbacks such as cumbersome operation, long analysis cycle, high consumption of chemical reagents, and environmental unfriendliness. With the development of spectroscopic analysis technology, inductively coupled plasma atomic emission spectrometry (ICP-AES) has been increasingly applied to the chemical composition analysis of steel and alloys due to its advantages such as fast detection speed, high sensitivity, and wide linear range.
[0003] However, determining the boron content in steel using ICP-AES still faces a series of technical challenges. First, since over 95% of steel grades have boron content below 0.05%, detection must be performed at a wavelength of 182.641 nm in the ultraviolet region. However, elements such as phosphorus, sulfur, and carbon cause spectral interference at this wavelength, leading to decreased detection accuracy. Second, boron in steel readily forms tungsten carbide and nitride with elements such as tungsten and nitrogen. If these are not sufficiently destroyed during sample pretreatment, boron cannot completely enter the solution, affecting the representativeness of the measurement results. To address these issues, existing methods typically use a mixed acid of nitric acid and hydrochloric acid to decompose the sample, or add hydrofluoric acid after the mixed acid decomposition to destroy the carbides and nitrides. However, practice shows that these methods are only suitable for low-carbon steel with a carbon content below 0.1%, limiting their applicability. More importantly, during the addition of hydrofluoric acid, boron readily reacts with fluorine to form boron trifluoride (BF3), which volatilizes and escapes, resulting in a systematically low measurement result.
[0004] Furthermore, while existing publicly available methods mention using 182.641 nm as the analytical spectral line for boron, they do not provide a clear solution for effectively subtracting multiple coexisting elements (such as tungsten, molybdenum, cobalt, cerium, and lanthanum) that cause interference at this wavelength. This makes it difficult for existing methods to guarantee the accuracy and stability of detection results in practical applications. Summary of the Invention
[0005] In view of this, the present invention proposes a method for detecting boron content in steel, which can effectively eliminate spectral overlap interference from coexisting elements such as tungsten, molybdenum and cobalt in steel, and improve the accuracy and reliability of boron content determination in complex matrix samples.
[0006] To achieve the above objectives, embodiments of the present invention provide a method for detecting the boron content in steel, specifically comprising the following steps: S1. Dissolve the steel sample with a solvent to obtain the test solution; S2. Prepare a series of standard solutions and measure the intensity of the first analytical line of boron in the standard solutions to establish a calibration curve; S3. Measure the intensity of the second analytical line of boron in the test solution, and obtain the instrument measurement value of boron based on the calibration curve and the intensity of the second analytical line; S4. Measure the content of interfering elements in the test solution, and perform calibration calculations based on the content of interfering elements and the instrument measurement values of boron in the standard series solutions to obtain the boron content in the steel sample.
[0007] In some embodiments, in step S1, the solvent includes a mixed acid prepared from hydrochloric acid and nitric acid, the mixing ratio of hydrochloric acid and nitric acid being determined according to the steel grade of the steel sample, including low alloy steel, stainless steel, blade steel and tungsten-molybdenum alloy.
[0008] In some implementations, step S1 includes: Perchloric acid was added to the dissolved steel sample and heated until perchloric acid fumes were emitted, then cooled. After cooling, water, hydrochloric acid, and hydrogen peroxide were added and heated until bubbles were emitted, then cooled. The cooled solution was diluted to a predetermined volume and then filtered dry to obtain the solution to be tested.
[0009] In some implementations, step S1 includes: Hydrogen peroxide was added to the dissolved steel sample and heated until bubbles appeared. The sample was then cooled until the bubbles disappeared. Yttrium solution was added and the sample was cooled to room temperature again. The solution was diluted to a predetermined volume and then filtered dry to obtain the test solution.
[0010] In some embodiments, in step S2, several initial standard solutions are prepared based on boron standard solutions of a preset concentration, and a solvent is added to each initial standard solution to prepare each target standard solution. All target standard solutions are used as a standard series solution for measuring the intensity of the first analytical line of boron in them.
[0011] In some embodiments, in step S2, the intensity of emitted light from boron in a series of standard solutions is measured using a spectrometer to determine the intensity of the first analytical line, and a calibration curve is established with boron concentration as the abscissa and the intensity of the first analytical line as the ordinate.
[0012] In some embodiments, in step S3, the intensity of the emitted light of boron in the test solution is measured using a spectrometer to determine the intensity of the second analytical line; the intensity of the second analytical line is substituted into the calibration curve to obtain the instrument measurement value of boron.
[0013] In some embodiments, in step S4, a spectrometer is used to measure the intensity of the third analytical line of each interfering element in the test solution to establish a corresponding working curve. The content of the interfering element in the test solution is determined based on the working curve corresponding to each interfering element. The interfering elements include one or more of tungsten, molybdenum, cobalt, cerium and lanthanum.
[0014] In some embodiments, in step S4, the boron content in the steel sample is obtained by correcting the instrument measurement value of boron based on the content of interfering elements and the standard series solutions, including: Obtain the interference correction coefficients corresponding to each interference element, and calculate the total interference contribution value based on the content of each interference element and the interference correction coefficients. The average correction factor is determined based on a series of standard solutions, and the drift-corrected instrument measurement value is obtained based on the average correction factor and the instrument measurement value of boron. The boron content in the steel sample was obtained based on the instrument measurement value after drift correction and the total interference contribution value.
[0015] In some implementations, in step S4, determining the average correction factor based on a standard series of solutions includes: Select a target standard solution from the standard series solutions that matches the boron content in the test solution as the calibration reference solution; Before and after measuring the test solution with a spectrometer, the boron content of the calibration reference solution is measured to obtain the boron content measurement value. The first correction factor and the second correction factor are calculated based on the known concentration of the calibration reference solution and the two boron content measurement values, respectively. The average of the first correction factor and the second correction factor is taken as the average correction factor.
[0016] This invention offers at least the following beneficial technical effects: By optimizing the sample pretreatment process and employing a combination of mixed acid dissolution and treatment with perchloric acid and hydrogen peroxide, the use of phosphoric acid, sulfuric acid, and hydrofluoric acid is effectively avoided. This eliminates spectral interference from phosphorus, sulfur, and carbon, as well as boron loss due to the volatilization of boron trifluoride, ensuring the accuracy of the detection results. Simultaneously, by establishing a working curve and incorporating the content of interfering elements for correction calculations, the spectral overlap interference from coexisting elements such as tungsten, molybdenum, and cobalt in steel is eliminated, improving the accuracy and reliability of boron content determination in complex matrix samples. Furthermore, this method is simple to operate, rapid in detection, and environmentally friendly, making it suitable for the accurate determination of boron content across a wide range of steel grades, from low-alloy steel to high-temperature alloys. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a block diagram of an embodiment of the method for detecting boron content in steel provided by the present invention. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.
[0020] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.
[0021] Based on the above objectives, this invention provides a method for detecting boron content in steel, applicable to the determination of boron content in steel and ferroalloys, with a determination range of 0.0005% to 5.00% by mass percentage. This method achieves accurate and rapid determination of boron through optimized sample pretreatment processes and spectroscopic measurement techniques. Figure 1 As shown, the method for detecting boron content in steel includes the following steps: S1. Dissolve the steel sample with a solvent to obtain the test solution; S2. Prepare a series of standard solutions and measure the intensity of the first analytical line of boron in the standard solutions to establish a calibration curve; S3. Measure the intensity of the second analytical line of boron in the test solution, and obtain the instrument measurement value of boron based on the calibration curve and the intensity of the second analytical line; S4. Measure the content of interfering elements in the test solution, and perform calibration calculations based on the content of interfering elements and the instrument measurement values of boron in the standard series solutions to obtain the boron content in the steel sample.
[0022] The principle of the method is as follows: The steel sample is dissolved using a mixed acid solution of hydrochloric acid and nitric acid as a solvent; perchloric acid is heated to produce perchloric acid fumes to destroy carbides and nitrides, allowing complete release of boron. Then, water and hydrochloric acid are added to dissolve the salts. Niobic acid and tungstic acid precipitates are treated with hydrogen peroxide, and excess hydrogen peroxide is heated to decompose the dissolved tungstic acid, causing it to redeprecipitate; alternatively, the sample can be dissolved directly with a mixed acid solution of hydrochloric acid and nitric acid, followed by treatment with hydrogen peroxide to remove niobic acid and some tungstic acid precipitates. After diluting the solution to a certain volume and dry filtering, the atomized solution is introduced into an inductively coupled plasma. The emission intensity of boron is measured at the recommended analytical line wavelength, and the boron content is calculated using the working curve.
[0023] Unless otherwise specified, analytical grade reagents and high-purity water or water of equivalent purity were used in all analyses. Specific reagents are as follows: The reagents used include: hydrochloric acid, density ρ approximately 1.19 g / mL; nitric acid, density ρ approximately 1.42 g / mL; perchloric acid, mass fraction 70%–72%; and hydrogen peroxide, mass fraction 30%.
[0024] To facilitate internal standard calibration, a yttrium solution was also prepared: 20.00 mL of a 1000 g / L yttrium standard solution was transferred to a 2000.0 mL volumetric flask, 25.0 mL of nitric acid was added, and the solution was diluted to the mark with water and mixed well to obtain a 0.01000 g / L yttrium solution.
[0025] Boron standard solutions of different concentrations were prepared. Specifically, the boron standard solution (1.000 g / L) was prepared as follows: 5.7082 g of primary boric acid was weighed into a 1000 mL wide-mouth beaker, 500–700 mL of water was added, and the solution was heated and stirred until completely dissolved. After cooling to room temperature, the solution was transferred to a 1000.0 mL volumetric flask, diluted to the mark with water, and mixed well. The boron standard solution (200 μg / mL) was prepared as follows: 2.2833 g of primary boric acid was weighed into a 1000 mL wide-mouth beaker, 500–700 mL of water was added, and the solution was heated and stirred until completely dissolved. After cooling to room temperature, the solution was transferred to a 2000.0 mL volumetric flask, diluted to the mark with water, and mixed well. The boron standard solution (50 μg / mL) was prepared as follows: 50.00 mL of a 1.000 g / L boron standard solution was transferred to a 1000.0 mL volumetric flask, diluted to the mark with water, and mixed well. The preparation method for boron standard solution (10 μg / mL) is as follows: Transfer 10.00 mL of 1.000 g / L boron standard solution to a 1000.0 mL volumetric flask, dilute to the mark with water, and mix well. The preparation method for boron standard solution (5 μg / mL) is as follows: Transfer 10.00 mL of 1.000 g / L boron standard solution to a 2000.0 mL volumetric flask, dilute to the mark with water, and mix well.
[0026] Measurements were performed using an inductively coupled plasma atomic emission spectrometer, specifically the iCAP PRO XP model. The linear correlation coefficient of the working curve should be greater than 0.99 to ensure the accuracy of the measurement results. Samples were taken and prepared according to the methods specified in GB / T 20066 or the corresponding national standards.
[0027] The method for detecting boron content in steel according to this invention optimizes the sample pretreatment process by employing a mixed acid dissolution method combined with perchloric acid and hydrogen peroxide treatment. This effectively avoids the use of phosphoric acid, sulfuric acid, and hydrofluoric acid, thereby eliminating spectral interference from phosphorus, sulfur, and carbon, as well as boron loss due to the volatilization of boron trifluoride, ensuring the accuracy of the detection results. Simultaneously, by establishing a working curve and incorporating the content of interfering elements for correction calculations, the spectral overlap interference from coexisting elements such as tungsten, molybdenum, and cobalt in steel is eliminated, improving the accuracy and reliability of boron content determination in complex matrix samples. Furthermore, this method is simple to operate, rapid in detection, and environmentally friendly, making it suitable for the accurate determination of boron content in a wide range of steel grades, from low-alloy steel to high-temperature alloy steel.
[0028] In some embodiments, the purpose of step S1 is to convert the solid steel sample into a clear solution suitable for inductively coupled plasma atomic emission spectrometry (ICP-AES) measurement, while ensuring that the boron is completely dissolved without introducing interference.
[0029] This invention provides two sample processing methods, which are suitable for different detection needs and application scenarios.
[0030] Method 1 for sample preparation is suitable for sample analysis or arbitration analysis requiring precise control. Weigh the sample according to the boron content range in the sample as shown in Table 1, accurate to 0.1 mg, and place it in a 300 mL Erlenmeyer flask. The correspondence between boron content and sample weight is as follows: when the boron content is less than 0.001%, weigh 1.0 g of sample; when the boron content is 0.001%–0.005%, weigh 0.5 g of sample; when the boron content is 0.005%–0.05%, weigh 0.3 g of sample; when the boron content is 0.05%–0.10%, weigh 0.2 g of sample; when the boron content is 0.10%–5.00%, weigh 0.10 g of sample. The stock solution dilution volume is 100.0 mL for all samples, but for samples with a boron content of 0.10%–5.00%, the stock solution dilution volume is 250.0 mL.
[0031] Table 1
[0032] Depending on the steel grade, add 30–50 mL of a mixed acid prepared from hydrochloric acid and nitric acid according to the proportions shown in Table 2. Heat at a low temperature until the sample is completely decomposed, then cool slightly. The steel grades include low-alloy steel, stainless steel, blade steel, and tungsten-molybdenum alloys. The correspondence between the steel grade and the mixed acid ratio is as follows: for low-alloy steel, use a mixed acid with a hydrochloric acid to nitric acid volume ratio of 3+2; for stainless steel or blade steel, use a mixed acid with a volume ratio of 1+1; for high-temperature alloys with a tungsten-molybdenum content of less than 5%, use a mixed acid with a volume ratio of 1+5; for high-temperature alloys with a tungsten-molybdenum content of 5%–10%, use a mixed acid with a volume ratio of 1+10; for high-temperature alloys with a tungsten-molybdenum content greater than 10%, use a mixed acid with a volume ratio of 1+12.
[0033] Table 2
[0034] Add 10.0 mL of perchloric acid to the steel sample that has been completely dissolved using the above steps, mix well, and heat until perchloric acid fumes are emitted and fill the mouth of the bottle; allow it to cool slightly. This step is used to destroy any carbides and nitrides that may be present in the sample, ensuring complete release of boron. Then add 50 mL of water, mix well, add 10.0 mL of hydrochloric acid, and mix well. Add 10.0 mL of hydrogen peroxide, mix thoroughly immediately, and heat until a large number of bubbles are just generated; if there are too many bubbles, cool with a cold water bath; after a large number of bubbles disappear, heat to boiling until large bubbles are emitted, and cool to room temperature. Dilute with water according to the volumes specified in Table 1 and mix well. Perform dry filtration using slow-speed filter paper; use three layers of slow-speed filter paper for tungsten-containing samples and one layer for other samples. Collect the filtrate as the test solution. Throughout the preparation process, avoid using phosphoric acid, sulfuric acid, hydrofluoric acid, and organic complexing agents, as phosphoric acid and sulfuric acid will cause spectral interference at the analysis wavelength of boron, while hydrofluoric acid will cause boron to form volatile boron trifluoride, resulting in loss.
[0035] Method 2 for sample preparation is suitable for rapid testing of steel samples with carbon content below 0.10% and boron content in the range of 0.001% to 0.10%. Weigh the sample according to Table 3, accurate to 0.1 mg, and place it in a 100 mL quartz volumetric flask. The correspondence between boron content and sample weight is as follows: when the boron content is 0.001% to 0.005%, weigh 0.3 g of sample; when the boron content is 0.005% to 0.10%, weigh 0.2 g of sample.
[0036] Table 3
[0037] Add 20.0 mL of the corresponding proportions of hydrochloric acid and nitric acid mixture as shown in Table 2, and heat at low temperature until the sample is completely decomposed. Add 1.0 mL of hydrogen peroxide, mix well, and after a large number of bubbles disappear, add another 1.0 mL of hydrogen peroxide, mix well, and after a large number of bubbles disappear, add 5.00 mL of yttrium solution as an internal standard and mix well. Cool to room temperature, dilute with water to the mark, and mix well. If the solution is turbid or contains precipitate, filter slowly with filter paper and collect the filtrate as the test solution.
[0038] In some embodiments, in step S2, several initial standard solutions are prepared based on boron standard solutions of a preset concentration. A mixed acid and a solvent are added to each initial standard solution to prepare target standard solutions. All target standard solutions are used as a standard series solution for measuring the intensity of the first analytical line of boron in them. The intensity of the first analytical line is determined by measuring the emitted light intensity of boron in the standard series solution using a spectrometer. A calibration curve is established with boron concentration as the abscissa and the first analytical line intensity as the ordinate.
[0039] The working curve can be established using the standard sample method or the standard solution method.
[0040] When using the standard sample method, weigh 5-6 standard samples with a matrix similar to the test sample and a gradient of boron content. Process them according to the same sample processing method as in step S1 to prepare a series of working curve solutions. Using the reagent blank as the calibration blank, measure the emission intensity of boron in the working curve solutions from low to high. Plot the boron concentration on the x-axis and the analytical line intensity on the y-axis to obtain the working curve.
[0041] When using the standard solution method, a series of standards with different concentrations are prepared according to the boron content range. For boron content ≤0.100%, 0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 5.00 mL, 10.00 mL, 20.00 mL, 30.00 mL, and 40.00 mL of boron standard solution with a concentration of 5 μg / mL are added to a 300 mL quartz Erlenmeyer flask or a 100.0 mL quartz volumetric flask, respectively, as initial standard solutions. Mixed acid, perchloric acid, and hydrogen peroxide in the same proportions as in step S1 are added to each initial standard solution. The solution is then processed according to the same heating, cooling, volume adjustment, and dry filtration process as in step S1 to obtain the target standard solution. All target standard solutions are used as the standard series solutions. This processing method ensures that the physical properties and chemical matrix of the standard series solutions are highly consistent with those of the test solution, thereby guaranteeing the accuracy of calibration. The correspondence between the amount of boron standard solution (5.00 μg / mL) added and the boron content is shown in Table 4.
[0042] Table 4
[0043] For boron content ranging from 0.100% to 1.00%, 0 mL, 2.00 mL, 5.00 mL, 10.00 mL, 15.00 mL, and 20.00 mL of a 50 μg / mL boron standard solution were added to 300 mL quartz Erlenmeyer flasks as initial standard solutions. The target standard solutions were then obtained by processing the samples using the same method as in step S1. The relationship between the amount of boron standard solution (50.00 μg / mL) added and the boron content is shown in Table 5.
[0044] Table 5
[0045] For boron content ranging from 1.00% to 5.00%, 0 mL, 2.00 mL, 5.00 mL, 10.00 mL, 15.00 mL, 20.00 mL, and 25.00 mL of boron standard solution with a concentration of 200 μg / mL were added to 300 mL quartz Erlenmeyer flasks as initial standard solutions. The target standard solutions were then processed using the same sample preparation method as in step S1. The relationship between the amount of boron standard solution (200.00 μg / mL) added and the boron content is shown in Table 6.
[0046] Table 6
[0047] Start the inductively coupled plasma atomic emission spectrometer (ICP-AES) and allow it to warm up for at least 30 minutes before measurement. Optimize the instrument's operating parameters according to the instrument manual. After the instrument stabilizes, select a characteristic spectral line for boron, such as wavelength 182.641 nm. Select background control points near this line, such as left background at 182.636 nm and right background at 182.646 nm, for background correction to eliminate background radiation interference. Using a reagent blank as the calibration blank, measure the emission intensity of boron in a series of standard solutions from low to high. Plot the boron concentration on the x-axis and the intensity of the first analytical line on the y-axis to obtain a working curve, which serves as the calibration curve. The correlation coefficient should be greater than 0.99. The analytical spectra are shown in Table 7.
[0048] Table 7
[0049] In some embodiments, in step S3, the intensity of the emitted light of boron in the test solution is measured using a spectrometer to determine the intensity of the second analytical line; the intensity of the second analytical line is substituted into the calibration curve to obtain the instrument measurement value of boron.
[0050] Under the same instrument conditions as when establishing the working curve, the emitted light intensity of boron in the test solution prepared in step S1 was measured, and the instrument measurement value of boron was calculated by substituting it into the calibration curve. It should be noted that the instrument measurement value is not a physical quantity directly measured by the instrument, but rather an initial concentration result calculated by the instrument software from the directly measured light intensity based on the working curve. This result has not yet undergone subsequent drift correction and interference correction.
[0051] In some implementations, in step S4, a spectrometer is used to measure the intensity of the third analytical line of each interfering element in the test solution to establish a corresponding working curve, and the content of the interfering element in the test solution is determined based on the working curve corresponding to each interfering element.
[0052] For coexisting interfering elements that may exist in steel, including one or more of tungsten, molybdenum, cobalt, cerium, and lanthanum, under the same instrument conditions as for measuring boron, inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to simultaneously measure the spectral intensity of the interfering elements in the test solution, and the accurate content of these interfering elements in the test solution is calculated based on their respective working curves.
[0053] In some embodiments, in step S4, to eliminate the drift effect that may occur due to prolonged instrument operation, a quality control sample with a known content is measured before and after measuring the test solution. Specifically, a target standard solution matching the boron content in the test solution is selected from a series of standard solutions as a calibration reference solution, and this calibration reference solution is measured before and after measuring the test solution. A first correction factor and a second correction factor are calculated based on the standard concentration of the calibration reference solution and the two measurements, respectively. The average of the first and second correction factors is taken as the average correction factor, which is used to correct the drift of the instrument measurements. This operation ensures the stability and reliability of the measurement results. The following is a detailed explanation of this process: (1) The boron content in the calibration reference solution is a known standard value, denoted as W; (2) Before starting to measure a batch of test solutions, first measure the selected calibration reference solution. Record the instrument measurement value of boron in the calibration reference solution as Wo1. Calculate the first correction factor k1 based on the standard value of the calibration reference solution and the measured value. This first correction factor k1 reflects the degree of deviation of the instrument when measuring this content point under the current operating conditions. The calculation formula is: k1 = W / Wo1; (3) After establishing the first correction factor, begin measuring the test solution. Record the instrument reading of boron in each test solution, denoted as Wo2.
[0054] (4) After completing the measurement of a batch of test solutions, immediately measure the same calibration reference solution again. Record the instrument measurement value of boron in the calibration reference solution displayed at this time, denoted as Wo3. Calculate the final correction factor k2 based on the standard value of the calibration reference solution and the measured value. This second correction factor k2 reflects the degree of deviation of the instrument after completing a batch of sample measurements. The calculation formula is: k2 = W / Wo3; (5) For the test solution measured between two calibration reference solutions, the degree of instrument drift is considered to change linearly from k1 to k2. Therefore, the average of the initial calibration factor k1 and the final calibration factor k2 is taken as the average calibration factor k, and the calculation formula is: k = (k1 + k2) / 2; (6) The calculated average correction factor k is used to correct the drift of the instrument measurement value of boron in the test solution, and the drift-corrected instrument measurement value is denoted as . The calculation formula is: = Wo3× k.
[0055] To ensure the calibration effect, the number of test solutions that can be detected between two calibration reference solution measurements is controlled. When |k1 - k2| ≤ 0.01, it indicates that the instrument is stable during this period, and 2 to 4 test solutions can be detected between two calibration reference solution measurements; if |k1 - k2| > 0.01, it indicates that the instrument fluctuates greatly, and to ensure measurement accuracy, only 1 test solution can be detected between two calibration reference solution measurements.
[0056] The relationship between boron content and allowable difference is shown in Table 8 below.
[0057] Table 8
[0058] The drift correction steps described above effectively eliminate the influence of signal drift caused by long-term instrument operation on the test results, ensuring the stability and reliability of the measurement data. The preliminary boron content value after drift correction will be combined with subsequent interference element correction calculations to finally obtain the accurate boron content in the steel sample.
[0059] To eliminate interference from coexisting elements, interference correction is required for the measurement results. Based on the pre-determined interference correction coefficients for interfering elements such as tungsten, molybdenum, cobalt, cerium, and lanthanum, and the content of these interfering elements in the test solution, the total interference contribution value is calculated. The drift-corrected instrument measurement value is then summed or subtracted from the total interference contribution value to obtain the final boron content in the steel sample. The interference correction coefficients are shown in Table 7. For example, for different instrument models, the correction coefficient for tungsten can be 0 or 3.9 × 10⁻⁶. -5 The correction factor for cobalt can be 1.3 × 10⁻⁶.-5 Or 1.7×10 -5 The correction factor for molybdenum can be 8.1 × 10⁻⁶. -5 or -3.7×10 -4 The correction factor for cerium can be 2.4 × 10⁻⁶. -4 2.2×10 -4 1.9×10 -4 Or 1.7×10 -4 The correction factor for lanthanum can be 2.2 × 10⁻⁶. -4 2.3×10 -4 2.1×10 -4 Or 1.1×10 -4 The formula for calculating the boron content in a steel sample can be expressed as: ; In the formula, The boron content in the steel sample. Let be the content of the i-th interfering element. Let be the interference correction coefficient for the i-th interference element, and n be the number of interference elements.
[0060] A series of boron-containing standard samples were tested using the method of this invention, and the test results are shown in Table 9 below.
[0061] Table 9
[0062] In summary, the method for detecting boron content in steel provided by this invention is applicable to both precise analysis and rapid detection scenarios through two different sample treatment methods. The optimized acid dissolution system and hydrogen peroxide treatment process effectively avoid boron loss and interference. Combined with working curves and calibration calculations, it achieves accurate determination of boron content over a wide range in steel and ferroalloys. This method is standardized in operation, yields reliable results, and has good practicality and promotional value.
[0063] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. The sequence numbers of the disclosed embodiments of this invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.
[0064] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.
[0065] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.
Claims
1. A method for detecting boron content in steel, characterized in that, include: S1. Dissolve the steel sample with a solvent to obtain the solution to be tested; S2. Prepare a series of standard solutions and measure the intensity of the first analytical line of boron in the standard solutions to establish a calibration curve; S3. Measure the intensity of the second analytical line of boron in the test solution, and obtain the instrument measurement value of boron based on the calibration curve and the intensity of the second analytical line; S4. Measure the content of interfering elements in the test solution, and perform calibration calculations based on the content of interfering elements and the instrument measurement values of boron in the standard series solutions to obtain the boron content in the steel sample.
2. The method for detecting boron content in steel according to claim 1, characterized in that, In step S1, the solvent includes a mixed acid prepared from hydrochloric acid and nitric acid. The mixing ratio of hydrochloric acid and nitric acid is determined according to the steel grade of the steel sample. The steel grades include low alloy steel, stainless steel, blade steel and tungsten-molybdenum alloy.
3. The method for detecting boron content in steel according to claim 1, characterized in that, Step S1 includes: Perchloric acid was added to the dissolved steel sample and heated until perchloric acid fumes were emitted, then cooled. After cooling, water, hydrochloric acid, and hydrogen peroxide were added and heated until bubbles were emitted, then cooled. The cooled solution was diluted to a predetermined volume and then filtered dry to obtain the solution to be tested.
4. The method for detecting boron content in steel according to claim 1, characterized in that, Step S1 includes: Hydrogen peroxide was added to the dissolved steel sample and heated until bubbles appeared. The sample was then cooled until the bubbles disappeared. Yttrium solution was added and the sample was cooled to room temperature again. The solution was diluted to a predetermined volume and then filtered dry to obtain the test solution.
5. The method for detecting boron content in steel according to claim 2, characterized in that, In step S2, several initial standard solutions are prepared based on boron standard solutions of a preset concentration. A solvent is added to each initial standard solution to prepare each target standard solution. All target standard solutions are used as a standard series solution for measuring the intensity of the first analytical line of boron in them.
6. The method for detecting boron content in steel according to claim 1, characterized in that, In step S2, the intensity of the emitted light of boron in the standard series solutions is measured using a spectrometer to determine the intensity of the first analytical line, and a calibration curve is established with boron concentration as the abscissa and the intensity of the first analytical line as the ordinate.
7. The method for detecting boron content in steel according to claim 1, characterized in that, In step S3, the intensity of the emitted light of boron in the test solution is measured using a spectrometer to determine the intensity of the second analytical line; the intensity of the second analytical line is substituted into the calibration curve to obtain the instrument measurement value of boron.
8. The method for detecting boron content in steel according to claim 1, characterized in that, In step S4, the intensity of the third analytical line of each interfering element in the test solution is measured using a spectrometer to establish the corresponding working curve. The content of the interfering element in the test solution is determined based on the working curve corresponding to each interfering element. The interfering elements include one or more of tungsten, molybdenum, cobalt, cerium and lanthanum.
9. The method for detecting boron content in steel according to claim 8, characterized in that, In step S4, the boron content in the steel sample is calculated by correcting the instrument measurements of boron based on the content of interfering elements and the standard series solutions, including: Obtain the interference correction coefficients corresponding to each interference element, and calculate the total interference contribution value based on the content of each interference element and the interference correction coefficients. The average correction factor is determined based on a series of standard solutions, and the drift-corrected instrument measurement value is obtained based on the average correction factor and the instrument measurement value of boron. The boron content in the steel sample was obtained based on the instrument measurement value after drift correction and the total interference contribution value.
10. The method for detecting boron content in steel according to claim 9, characterized in that, In step S4, the average correction factor is determined based on the standard series solutions, including: Select a target standard solution from the standard series solutions that matches the boron content in the test solution as the calibration reference solution; Before and after measuring the test solution with a spectrometer, the boron content of the calibration reference solution is measured to obtain the boron content measurement value. The first correction factor and the second correction factor are calculated based on the known concentration of the calibration reference solution and the two boron content measurement values, respectively. The average of the first correction factor and the second correction factor is taken as the average correction factor.