Method for measuring niobium in high-speed steel and stainless steel

Abstract

The invention discloses a method for determining niobium in high-speed steel and stainless steel, which comprises the following steps: weighing 0.2000 g of sample in a polytetrafluoroethylene beaker, adding 20mL of mixed sample dissolving acid, dissolving in a low-temperature electric hot plate, taking down the dissolved sample, slightly cooling, adding 10mL of 15% tartaric acid, and making a blank sample; and a proper analysis spectral line is selected, so that the interference of Cr, Mo, V, W, Co and Al on Nb is avoided. The invention aims to establish a simple, convenient, rapid, accurate and reliable analysis method for determining niobium in high-speed steel and stainless steel by an ICP-AES method.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy analysis, and in particular relates to a method for determining niobium in high-speed steel and stainless steel. Background Art

[0002] High-speed steel is a complex matrix high-alloy steel, the main alloying elements are tungsten, molybdenum, chromium, vanadium, and some high-speed tool steels add cobalt, aluminum, niobium and other elements. Adding niobium to stainless steel can significantly improve strength and plasticity, improve comprehensive mechanical properties and welding performance, and enhance corrosion resistance. Therefore, it is very important to accurately determine the niobium content in high-speed steel and stainless steel.

[0003] At present, there is a national standard GB / T 223.40-2007 for the determination of niobium in carbon steel and low alloy steel. This method uses spectrophotometry to determine niobium, which is not suitable for the detection of niobium in high-speed steel and stainless steel. The determination of niobium in stainless steel only has the national standard GB / T11170-2008. The determination of multiple elements in stainless steel uses spark discharge atomic emission spectrometry. This method has strict requirements on the composition and structure of the sample and is not suitable for analyzing high-speed steel with complex matrix. There is no standard or relevant report on the detection of niobium in high-speed steel.

[0004] This method mainly studies the dissolution method, so that multiple elements such as Cr, Mo, V, W, Co, Al, Nb can coexist in hydrochloric acid, nitric acid, hydrofluoric acid and tartaric acid media; select appropriate analytical spectra to avoid the interference of Cr, Mo, V, W, Co, Al on Nb. Establish a simple, fast, accurate and reliable ICP-AES method for the determination of niobium in high-speed steel and stainless steel. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining niobium in high-speed steel and stainless steel, and to establish a simple, rapid, accurate and reliable ICP-AES analysis method for determining niobium in high-speed steel and stainless steel.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for determining niobium in high-speed steel and stainless steel, comprising the following steps:

[0008] Step 1: Prepare mixed sample dissolving acid: add 400 mL hydrochloric acid, 130 mL nitric acid, and 50 mL hydrofluoric acid to 400 mL water and mix well;

[0009] Step 2: Weigh 0.2000g of sample into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, cool it slightly, add 10mL of 15% tartaric acid, and make a blank sample at the same time;

[0010] Step 3: After the sample solution cools to room temperature, transfer it to a 100 mL polytetrafluoroethylene volumetric flask, dilute to the mark with high-purity water, and shake well;

[0011] Step 4: Preparation of standard calibration curve solutions

[0012] Niobium single element standard solution: concentration is 1000 μg / mL, from the National Center for Standard Materials;

[0013] Weigh 6 portions of 0.2g of high-purity iron respectively into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, cool it slightly and add 10mL of 15% tartaric acid, wait for the sample solution to cool to room temperature, add niobium single element standard solution, and prepare a solution containing Nb0, 0.010%, 0.050%, 0.25%, 1.00%, 5.00%, transfer the solution to a 100mL polytetrafluoroethylene volumetric flask, dilute to the scale with high-purity water, and shake well; this solution is used to prepare the standard curve;

[0014] Step 5: Select the spectrum line

[0015] By measuring the Nb standard solution, the spectral line position was adjusted to determine Nb269.706 nm, and after correction, Nb269.729 nm was used as the analysis line;

[0016] Step 6: Draw a calibration curve: introduce the standard calibration curve solution into the inductively coupled plasma emission spectrometer, measure the signal intensity of the Nb ion, and draw a calibration curve with the mass percentage of the element as the abscissa and the emission intensity of the element as the ordinate;

[0017] Step 7: The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Nb ions, and the Nb content in the sample solution is calculated based on a calibration curve of a standard solution with a known mass percentage;

[0018] The content of Nb element in the sample is calculated as follows:

[0019] W%=W i -W0

[0020] Where: W-mass percentage of the element in the sample;

[0021] W0-mass percentage of the element in the blank solution to be tested;

[0022] W i -The mass percentage of the element in the sample to be measured.

[0023] Furthermore, the measuring instrument is Optima 5300DV, produced by PE Company, USA.

[0024] Furthermore, the sample introduction system is a polyethylene nebulizer.

[0025] Furthermore, the observation method is horizontal observation.

[0026] Furthermore, the detection range is: Nb 0.0100~5.00%.

[0027] Furthermore, less chemical reagents are used, which not only saves materials but also reduces the discharge of chemical waste liquid.

[0028] Furthermore, the method is simple to operate, has a short operation process and a fast detection speed.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are:

[0030] 1. The present invention uses less chemical reagents: only 9 mL of hydrochloric acid, 3 mL of nitric acid, 1.5 mL of hydrofluoric acid, and 10 mL of tartaric acid (15%) are used. The less chemical reagents used not only save materials but also reduce the discharge of chemical waste liquid.

[0031] 2. Establish an ICP-OES method for determining niobium in high-speed steel and stainless steel, filling the gap in the method for detecting niobium in high-speed steel. This method is simple to operate, has a short operation process and a fast detection speed.

[0032] 3. Use horizontal observation method to increase the signal intensity of Nb, thereby improving the sensitivity of the measurement.

[0033] 4. Selecting Nb269.729 nm as the analysis line avoids the interference of vanadium, tungsten and molybdenum and improves the accuracy of detection.

[0034] 5. The detection range of niobium in high-speed steel and stainless steel of the present invention is 0.0100-5.00%. The present invention has good application effect through multiple inspections of high-speed steel and stainless steel samples, and provides reliable data for the detection of niobium in high-speed steel and stainless steel. This method can be promoted in the metallurgical industry. DETAILED DESCRIPTION

[0035] In the embodiments of the present invention, the reagents used are preferably:

[0036] Hydrochloric acid, nitric acid, hydrofluoric acid: high-grade purity;

[0037] Prepare mixed sample dissolving acid: add 400 mL hydrochloric acid, 130 mL nitric acid and 50 mL hydrofluoric acid into 400 mL water and mix well.

[0038] Tartaric acid (15%) aqueous solution;

[0039] Niobium single element standard solution: concentration is 1000μg / mL, sourced from the National Standard Material Center.

[0040] 100mL polytetrafluoroethylene volumetric flask; Argon: argon purity ≥99.9%; Compressed air.

[0041] The preferred inductively coupled plasma emission spectrometer model is Optima 5300DV of PE Company; the observation method is horizontal observation; and the sample injection system is a polyethylene atomizer.

[0042] Sample analysis

[0043] Decomposition sample

[0044] Weigh 0.2000g of sample into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, cool it slightly and add 10mL of 15% tartaric acid, after the sample solution cools to room temperature, transfer it to a 100mL polytetrafluoroethylene volumetric flask, dilute to the scale with high-purity water, shake well, and make a blank sample at the same time.

[0045] Preparation of standard calibration curve solutions

[0046] Weigh 6 portions of 0.2g of high-purity iron into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, add 10mL of 15% tartaric acid after cooling slightly, add niobium single element standard solution after the sample solution cools to room temperature, and prepare a solution containing Nb0, 0.010%, 0.050%, 0.25%, 1.00%, 5.00%, transfer to a 100mL polytetrafluoroethylene volumetric flask, dilute to the scale with high-purity water, and shake well. This solution is used to make a standard curve.

[0047] Plot the calibration curve:

[0048] Select the spectrum line: determine Nb269.706 nm, and after correction, use Nb269.729 nm as the analysis line. Introduce the standard calibration curve solution into the inductively coupled plasma emission spectrometer to measure the signal intensity of the Nb ion, and draw a calibration curve with the mass percentage of the element as the horizontal axis and the emission intensity of the element as the vertical axis.

[0049] Determination:

[0050] The sample solution and the blank sample solution were introduced into the inductively coupled plasma emission spectrometer to measure the signal intensity of Nb ions, and the Nb content in the sample solution was calculated based on the calibration curve of the standard solution with known mass percentage.

[0051] The content of Nb element in the sample is calculated as follows:

[0052] W%=W i -W0

[0053] Where: W-mass percentage of the element in the sample;

[0054] W0-mass percentage of the element in the blank solution to be tested;

[0055] W i - mass percentage of the element in the sample to be tested;

[0056] The detection range of this method is: Nb 0.0100%~5.00%.

[0057] Example 1

[0058] A working curve was prepared according to the above method, and the curve correlation coefficient r of Nb was 0.999998. Eleven blank solutions were prepared according to the experimental method and measured three times. According to the detection limit formula CL=3Sb / k (Sb is the standard deviation of the blank, k is the corresponding slope of the calibration curve) defined by the International Union of Pure and Applied Chemistry (IUPAC), the detection limit of Nb was calculated to be 0.0011 μg / mL.

[0059] Example 2 Accuracy Test

[0060] In order to evaluate the accuracy of the method, high speed steel and stainless steel standard materials were measured, and the results are shown in Table 1.

[0061] Table 1 Accuracy test

[0062] Sample name serial number Certification value% Measured value% Stainless steel YSBC15342-2008 0.613 0.618 Stainless steel YSBC15343-2008 0.024 0.023 High temperature steel GBW02551 1.52 1.513 New high speed steel 80110 0.319 0.319 New high speed steel 80111 0.481 0.486 New high speed steel 80108 0.0866 0.0872 Stainless steel GSB03-2030-06 2.42 2.404

[0063] In order to verify the upper limit of the determination of the method, the recovery rate tests of high-speed steel sample 1#, stainless steel sample 1#, and standard substances were carried out. The results are shown in Table 2.

[0064] Table 2 Spike recovery test

[0065]

[0066]

[0067] Example 3 Method Precision

[0068] Under the selected experimental method, weigh the high-speed steel sample 2 # , 3 # And stainless steel sample 2 # , 3 # , 8 sample solutions were prepared in parallel for precision investigation. The standard deviation (SD) and relative standard deviation (RSD) of the determination results of each component were calculated, Table 3.

[0069] Table 3 Precision test results

[0070]

[0071] Therefore, through the verification of the above implementation examples, it can be seen that the detection range of the ICP-OES method for determining niobium in high-speed steel and stainless steel is 0.0100% to 5.00%. The invention has a good application effect through multiple inspections of high-speed steel and stainless steel samples. The invention has the characteristics of wide linear range, high sensitivity, simple operation, fast analysis speed, accurate and reliable analysis results, and provides reliable data for the detection of niobium in high-speed steel and stainless steel.

[0072] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for determining niobium in high-speed steel and stainless steel, characterized in that: The following steps are involved: Step 1: Prepare mixed sample dissolving acid: add 400 mL hydrochloric acid, 130 mL nitric acid, and 50 mL hydrofluoric acid to 400 mL water and mix well; Step 2: Weigh 0.2000g of sample into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, cool it slightly, add 10mL of 15% tartaric acid, and make a blank sample at the same time; Step 3: After the sample solution cools to room temperature, transfer it to a 100 mL polytetrafluoroethylene volumetric flask, dilute to the mark with high-purity water, and shake well; Step 4: Preparation of standard calibration curve solutions Niobium single element standard solution: concentration is 1000 μg / mL, from the National Center for Standard Materials; Weigh 6 portions of 0.2g of high-purity iron respectively into a polytetrafluoroethylene beaker, add 20mL of mixed dissolving acid and dissolve on a low-temperature electric hot plate, remove the dissolved sample, cool it slightly, add 10mL of 15% tartaric acid, wait for the sample solution to cool to room temperature, add niobium single element standard solution, and prepare a solution containing Nb0, 0.010%, 0.050%, 0.25%, 1.00%, and 5.00%. Transfer the solution to a 100mL polytetrafluoroethylene volumetric flask, dilute to the scale with high-purity water, and shake well; This solution is used to prepare the standard curve; Step 5: Select the spectrum line By measuring the Nb standard solution, the spectral line position was adjusted to determine Nb269.706 nm, and after correction, Nb269.729 nm was used as the analysis line; Step 6: Draw a calibration curve: introduce the standard calibration curve solution into the inductively coupled plasma emission spectrometer, measure the signal intensity of the Nb ion, and draw a calibration curve with the mass percentage of the element as the abscissa and the emission intensity of the element as the ordinate; Step 7: The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Nb ions, and the Nb content in the sample solution is calculated based on a calibration curve of a standard solution with a known mass percentage; The content of Nb element in the sample is calculated as follows: W%=W i -W0 Where: W-mass percentage of the element in the sample; W0-mass percentage of the element in the blank solution to be tested; W i -The mass percentage of the element in the sample to be measured.

2. The method for determining niobium in high speed steel and stainless steel according to claim 1, characterized in that: The measuring instrument is Optima 5300DV, produced by PE Company, USA.

3. The method for determining niobium in high speed steel and stainless steel according to claim 2, characterized in that: The injection system was a polyethylene nebulizer.

4. The method for determining niobium in high speed steel and stainless steel according to claim 2, characterized in that: The observation method is horizontal observation.

5. The method for determining niobium in high speed steel and stainless steel according to claim 1, characterized in that: Detection range: Nb0.0100~5.00%.

6. The method for determining niobium in high speed steel and stainless steel according to claim 1, characterized in that: Less chemical reagents are used, which not only saves materials but also reduces the discharge of chemical waste liquid.

7. The method for determining niobium in high speed steel and stainless steel according to claim 1, characterized in that: The method has the advantages of simple operation, short operation process and fast detection speed.

Images