AU2021102203A4

AU2021102203A4 - Method for quickly determining yttrium content in steel by using full spectrum spark direct reading spectrometry

Info

Publication number: AU2021102203A4
Application number: AU2021102203A
Authority: AU
Inventors: Chaobin Lai; Jie Li; Chunfa LIAO; Fan Liu; Jianfeng Liu; Min Liu; Zhifang Liu; Diqiang Luo; Yong SHUAI; Changqing Wang; Yinhong Yu; Bo ZENG; Zhenming Zhang
Original assignee: Jiangxi University of Science and Technology; Xinyu Iron and Steel Co Ltd
Current assignee: Jiangxi University of Science and Technology; Xinyu Iron and Steel Co Ltd
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2021-06-17
Anticipated expiration: 2029-04-27

Abstract

The invention discloses a detection method for quickly determining yttrium content in steel by using full spectrum spark direct reading spectrometry, which comprises the following steps: refining steel ingots with different yttrium contents by changing the addition amount of rare earth yttrium, and rolling into steel billets. A standard sample is taken from one section of billet, and the uniformity of the standard sample is detected by spark direct reading instrument, and the sample with the best uniformity is selected as the standard sample. Sampling drill cuttings on standard samples, preparing standard solutions, and determining yttrium content in the standard solutions by ICP-AES. The standard sample is excited and calibrated to obtain the strength ratio, and the standard analysis curve of rare earth yttrium element is formed by fitting the strength ratio with yttrium content. The method can quickly detect the yttrium content in steel, and has important practical scientific value and economic and social significance for researching and popularizing the application of yttrium in steel. 1/1 FIGURES A Poish chanfi Fig 1 A -AZ content NewFunction (User) Fit of content 0.06 0 2 0.02 0.00 0 1000000 2000000 3000000 4000000 light intensity Fig.2 a a b c Statistics Value Error Value Error Value Error Reduced Chi-Sqr Adj R-Square content -1.97843E-15 3.53869E-16 285535E-B 128482E-9 -0002 706773E-4 9.37421E-7 0.99881 Fig.2 b

Description

1/1

FIGURES A

Poishchanfi

Fig 1

A -AZ content NewFunction (User) Fit of content

0.06

0 2

0.02

0.00

0 1000000 2000000 3000000 4000000 light intensity

Fig.2 a

a b c Statistics Value Error Value Error Value Error Reduced Chi-Sqr Adj R-Square content -1.97843E-15 3.53869E-16 285535E-B 128482E-9 -0002 706773E-4 9.37421E-7 0.99881

Fig.2 b

Method for quickly determining yttrium content in steel by using full spectrum

spark direct reading spectrometry

TECHNICAL FIELD

The invention belongs to the technical field of rare earth yttrium detection methods,

and particularly relates to an on-line rapid detection method of rare earth yttrium content

in steel.

BACKGROUND

Rare earth elements play an increasingly prominent role in molten steel, which is

expected to become an important element in developing new high value-added steel

materials in the 21st century. Adding a small amount of heavy rare earth yttrium into

steel can significantly improve the mechanical properties and mechanical properties of

steel. However, there is no relevant standard method for the determination of yttrium

content (mass fraction) in steel in domestic and foreign standards at present. The standard

of EDTA titration is adopted for the single rare earth content in GB/T 14635 "Chemical

Analysis Methods of Rare Earth Metals and Their Compounds". This method is

cumbersome and cannot meet the requirements of on-line rapid detection in the

production practice, and it is difficult to meet the requirements of yttrium content (mass

fraction) detection in steel.

Spark direct reading spectrum analysis is one of the important means of rapid

metallurgical analysis, but it is also a relative measurement method, which must be

compared with corresponding standard materials, and at the same time, special channels

and spectral lines for rare earth yttrium detection are needed. At present, there are relatively few standard materials for metallurgical analysis containing rare earth elements in China, especially the standard materials for steel containing yttrium, which are not available in the market and have not been reported at home and abroad However, the traditional spark direct reading spectrometer has not developed a special channel and spectral line for measuring yttrium, which leads to the bottleneck of studying the action and mechanism of yttrium in steel. Full-spectrum spark direct reading spectrometer can realize full-spectrum scanning without channel limitation and solve the problem of no yttrium channel. However, there is no yttrium detection method for full spectrum spark direct reading spectrometer. Therefore, the research and development of yttrium containing steel reference materials and rapid detection methods have important practical scientific value and economic and social significance for the research and popularization of the application of yttrium in steel.

SUMMARY

In view of the above-mentioned prior art, the object of the present invention is to

provide a detection method for rapidly determining yttrium content in steel by using full

spectrum spark direct reading spectrometry. The method can quickly detect the yttrium

content in steel, and has important practical scientific value and economic and social

significance for researching and popularizing the application of yttrium in steel.

In order to achieve the above purpose, the invention adopts the following technical

scheme:

The invention provides a detection method for rapidly measuring yttrium content in

steel by using full spectrum spark direct reading spectrometry, which comprises the

following steps:

(1) By changing the amount of rare earth yttrium, steel ingots with different yttrium

contents are refined and rolled into billets.

(2) Taking a plurality of samples on one section of each billet obtained in the step

(1) and carrying out surface treatment, selecting the best working spectral line of the full

spectrum spark direct reading spectrometer according to the principle of minimum

interference of elements, detecting the uniformity of the samples by using the best

working spectral line, and selecting the sample with the best uniformity as a standard

sample.

(3) Sampling drill cuttings on the standard sample obtained in step (2), preparing a

standard solution, and calibrating the yttrium content in the standard solution by ICP

AES.

(4) Performing excitation calibration on the standard sample obtained in step (2) to

obtain an intensity ratio, establishing a corresponding relationship between the intensity

ratio and the yttrium content obtained in step (3), and drawing a rare earth yttrium

element standard analysis curve; The mathematical model of yttrium is obtained by

fitting the standard analysis curve, and the steel with unknown rare earth yttrium content

is detected by using the standard analysis curve of rare earth yttrium.

Preferably, in step (1), the steel billet is prepared by the following method:

SOL. a magnesium oxide crucible is built in a medium frequency induction furnace,

baked and washed with matrix raw materials; The addition amount of matrix raw

materials and pure rare earth yttrium is determined by proportioning calculation, and the

raw materials are polished, weighed and put into a magnesium oxide crucible.

S02. start vacuumizing and slowly raise the temperature, keeping the vacuum degree

at 6.67x10-1 Pa. When the base material is completely melted, pure rare earth yttrium is

added and kept warm, and then poured into a casting mold after melting, forged after

demoulding, and rolled into a billet with a thickness of 30mm.

Preferably, in step S01, the purity of the rare earth yttrium is 99.9%.

Preferably, in step SO1, the matrix material consists of the following chemical

components in percentage by mass:

C 0.09%, Mn 1.34%, S 0.006%, P 0.021%, Si 0.2%, Als 0.027%, N 0.0044%, Nb

0.029%, Ca 0.0013%, Ti 0.011%, Sn 0.0044% and the balance Fe.

Preferably, in step (3), the working conditions of the spark direct reading instrument

are as follows: the discharge frequency is 400-500 Hz. The argon flow rate is 220-2301/h.

Environmental temperature 25°C/ light room temperature 20°C, humidity 5 0 - 6 0 %,

purging time is 1, the excitation time is 12s, and the precombustion time is 4s.

Preferably, in the step (2), the uniformity detection is that a full spectrum spark

direct reading spectrometer is used to dot and scan the surface of a standard sample, and

each standard sample is marked with 8 dots, and the uniformity of the sample is judged

by the relative standard uncertainty of the intensity ratio.

According to the standard uncertainty (UA1) and relative standard uncertainty

(U(rel,A1)) of repetitive test data, the stability of the data is checked. The smaller the

relative standard uncertainty (U(rel,A1)), the smaller the data difference, the better the

stability, that is, the better the uniformity.

Preferably, in step (2), the working spectral line is XY=371.029nm.

Preferably, in step (3), the standard solution is prepared by the following method:

Al. Take 0.50g of steel scrap, add 25mL of mixed solution prepared by water,

hydrochloric acid and nitric acid according to the mass ratio of 1: 1: 3 until the steel scrap

is completely dissolved, add 5mL of perchloric acid, heat until perchloric acid smokes,

and continue heating until the volume of test solution remains 1-2 ml.

A2. Add 20mL of water and 5mL of hydrochloric acid after cooling the test solution,

heat and dissolve until the test solution is clear and free of impurities, and cool to room

temperature to obtain standard solution.

Preferably, in step (3), sampling is carried out according to the method specified in

GB/T20066-2006, and the surface of the sample is ground after sampling, and the particle

size of the ground material is 0.124-0.25 mm.

Sampling method: sampling is respectively carried out on a cross section of the billet

prepared in step (1) and a quarter of the diagonal line of the cross section, and the

distance between the edge of the sample and the edge of the cross section is 1mm.

Sampling diagram is shown in Figure 1.

Preferably, in step (4), the standard analysis curve is that the mathematical model is

y=1.94724*10 8 x2 +3.16856*10 7 x+89329.93426, where x is the element content, Y is the

intensity ratio.

The invention has the beneficial effects that:

According to the invention, yttrium-containing steel calibration samples are

researched and developed. The standard analysis curve of yttrium was drawn by full

spectrum spark direct reading spectrometer, and the content of yttrium in steel was

determined. The detection method provided by the invention is rapid, accurate, good in repeatability and stability, and has important practical scientific value and economic and social significance for researching and popularizing the application of yttrium in steel.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1: Sampling diagram of sample uniformity test;

Fig. 2: A is the standard analysis curve of yttrium, and B is the fitting parameter;

DESCRIPTION OF THE INVENTION

It should be noted that the following detailed description is exemplary and is

intended to provide further explanation for this application. Unless otherwise specified,

all technical and scientific terms used herein have the same meanings as commonly

understood by those of ordinary skill in the technical field to which this application

belongs.

As introduced in the background section, adding a small amount of heavy rare earth

yttrium into steel can significantly improve the mechanical properties and mechanical

properties of steel. However, there is no relevant standard method for the determination

of yttrium content (mass fraction) in steel in domestic and foreign standards at present.

Due to the low content of yttrium in steel, it is difficult to detect the content of yttrium in

steel by the existing technology.

Based on this, the purpose of the present invention is to provide a detection method

for on-line rapid determination of yttrium content in steel by full spectrum spark direct

reading spectrometry. The method comprises the following steps: firstly, establishing a

standard material for steel containing yttrium, developing a standard analysis curve of

yttrium, and establishing a mathematical model of yttrium.

Working principle of full spectrum spark direct reading spectrometer:

Discharge between the prepared block sample and the counter electrode under the

action of spark light source generates plasma in high temperature and inert atmosphere.

When the atom of the measured element is excited, the electrons transition between

different energy levels in the atom, and when the transition from high energy level to low

energy level is the generated characteristic spectral line, measure the spectral intensity of

the selected analysis element and internal standard element characteristic spectral line.

According to the relationship between spectral line intensity and concentration of the

measured element in the sample, the content of the measured element is calculated by

calibration curve.

Based on the above working principle, the relationship between the strength ratio

and the content of yttrium element is established, and the standard analysis curve of rare

earth yttrium element is formed, thus realizing the accurate customization of the standard

analysis curve.

The method realizes on-line rapid detection of yttrium content in steel. At the same

time, the standard samples of iron and steel containing yttrium were prepared. The

method solves the problem of how to accurately hit the required yttrium content in steel

in yttrium content detection, that is, how to accurately hit the target component. In order

to achieve this goal, multi-heats smelting is adopted, from which the best choice is made.

The medium frequency induction melting furnace used in preparing the calibration

sample has electromagnetic stirring function, which can effectively promote the full and

uniform mixing of all components in steel. The yttrium content in the steel ingot cannot

be directly obtained by adding yttrium with different qualities to the steel ingot in step 1

of the invention, because yttrium will burn to different degrees in the smelting process, and the yield of yttrium in each furnace steel cannot be guaranteed to be completely the same. Different amounts of rare earth yttrium are added for refining standard samples with different yttrium contents, and the yttrium content in each furnace steel has a gradient through different addition amounts. The value of yttrium content in refined steel ingot cannot be determined, so it needs to be determined by ICP-AES. This method is a chemical analysis method, which can determine the content of all chemical elements in theory, and has a mature technical development. However, compared with spark direct reading spectrum detection, ICP-AES detection takes a long time and has low efficiency, which can not meet the demand of online rapid detection in the production process. In actual detection, the composition of the steel containing yttrium (Y) does not have to be exactly the same as the chemical composition and content of the raw materials in the invention, but the chemical composition and content of the raw materials are different, which has no obvious influence on the detection of yttrium content. The method of the invention can quickly detect the content of Y in steel and achieve the purpose of quick analysis and detection required by the production line. And it is not a destructive test, which can keep the integrity of steel.

In order to enable those skilled in the art to understand the technical scheme of this

application more clearly, the technical scheme of this application will be described in

detail with specific examples below.

Test materials used in the embodiments of the invention are all conventional test

materials in the field and can be purchased through commercial channels.

Example 1

Step 1: Sample preparation

Using medium frequency induction furnace, steel ingots with different yttrium

contents were refined and rolled into billets by changing the addition amount of rare earth

yttrium. Eight standard samples were smelted in total, and the sample numbers were Z1,

Z2, Z3, Z4, Z5, Z6, Z7 and Z8 respectively.

Operation steps are as follows:

The crucible in the medium frequency induction furnace is a crucible with built-in

magnesium oxide, which is baked and washed with matrix raw materials. The addition

amount of matrix raw materials and pure rare earth yttrium is determined by batching

calculation, grinding raw materials, weighing, putting matrix raw materials into crucible,

putting rare earth pure Y into silo, wherein the purity of rare earth yttrium is 99.9%, the

chemical composition of magnesium oxide crucible is shown in Table 1, and the

chemical composition of substrate is shown in Table 2.

Start vacuumizing and slowly raise the temperature, keeping the vacuum degree at

6.67x101 Pa. The melting state of matrix raw materials was observed, and the total

melting time was about 70mins. Add rare earth into that silo, keep the temperature for

about 2mins, and carry out electromagnetic stirring. Electromagnetic stirring is beneficial

to the homogenization of temperature and alloy composition, ensures the uniformity of

the calibration sample, confirms the molten state, pours it into the corresponding mold,

knocks the ingot after demoulding, and rolls it into a steel plate with a thickness of

mm.

Table 1 Chemical composition of crucible chemical MgO SiO 2 A1 2 0 3 CaO Fe203 composition content >97.5 <0.70 <0.10 <1.10 <0.460

The selection of crucible has a certain influence on the preparation of steel ingot, so

the magnesium oxide crucible is selected to reduce the influence of crucible on the

preparation of steel ingot.

Table 2 Chemical composition of substrate element C Mn S P Si Als

content (

0.09 1.34 0.006 0.021 0.2 0.027

element N Nb Ca Ti Sn others

content ( The 0.0044 0.029 0.0013 0.011 0.0044 allowance isFe

Step 2: Uniformity test

Sampling is carried out at 1/4 of the diagonal line of one side of each billet refined in

step one and 1mm away from the edge of the side, and four samples with specifications

of 20mm*20mm*10mm are obtained from each calibration sample, as shown in Figure 1.

And the samples are numbered. In order to prevent the surface oxidation and pollution of

steel samples from affecting the accuracy and precision of data, a milling machine is used

to grind the surface of the samples, and the particle size of the grinding material is 0.2

mm.

In this experiment, SPECTROLAB S spark direct reading instrument is used to test

the uniformity of standard samples. The working conditions of SPECTROLAB S spark

direct reading instrument are: discharge frequency 450Hz. The argon flow rate is 2201/h.

Environmental temperature 25°C/ light room temperature 20°C, humidity 50-60%,

Purging time is Is. The excitation time is 12s, and the precombustion time is 4s.

According to the above working conditions, the upper surface of the sample is scanned

with SPECTROLAB S spark direct reading instrument to measure its intensity ratio.

According to the principle of minimum interference of elements, the working spectral

line is selected from the measuring spectral lines recommended by the instrument. the

working spectral line selected in this experiment isXY=371.029nm. The full spectrum

spark direct reading spectrometer is used to scan the upper surface of the sample by

dotting. Each sample is randomly selected from one side, and 8 points are punched. The

uniformity of the sample is judged by the relative standard uncertainty of intensity ratio,

and a sample with the best uniformity is selected as the standard sample in each group for

drawing the standard analysis curve. Eight steel plates Z1-Z8 prepared in step one, and

the strength ratio of each steel plate for uniformity detection is shown in Table 3.

Table 3 Strength ratio of uniformity samples Sample S RSD U (A, 1) Urel (A, 1) No. Zi 45706 1136.82 2.49 401.93 0.0088 Z2 49594 903.28 1.82 319.36 0.0064 Z3 141804 5037 3.55 1780.85 0.0126 Z4 177574 4079.22 2. 3 1442.22 0.0081 Z5 261809 5998.8 2.29 92563.46 0.3511 Z6 520329 12208.28 2. 35 4316.28 0.0083 Z7 754800 8114.46 1.08 2868.9 0.0038 Z8 986454 16926.24 1. 72 5984. 33 0.0061

The data of 8 points measured on each calibration sample are investigated, and the

data stability is checked by calculating the standard uncertainty (UAl) and the relative

standard uncertainty (U(rel,Al) of repetitive test data. The smaller the relative standard

uncertainty (U(rel,Al)), the smaller the data difference, the better the stability, that is, the

better the uniformity.

Standard uncertainty of passing repeatability test:

The relative standard uncertainty of repeatability test is:

S U(rei,A1)=" (1.2)

In which: S is the standard deviation of the sample to be measured;

N: determination times of a single sample;

X: the average value of the sample to be measured.

The measured standard uncertainty (UAl) and relative standard uncertainty

(U(rel,Al)) of calibration sample data and data repeatability test are shown in table 3 below.

Judging the uniformity of the data in Table 3, we can see that the relative standard

deviation (RSD) is less than 5%, which meets the requirement that the absolute value

between the two test results should not exceed the probability of 95% under the

conditions of repeatability and reproducibility. It shows that the data fluctuation of 8

points of each calibration sample is small, which proves that the uniformity of the refined

calibration sample is good and that the calibration sample is desirable.

The closer the relative standard uncertainty (U(rel,Al)) is to 1, the worse the data

stability is. The relative standard uncertainties(U(rel,Al)) in the table are all less than 1, and

the values are all small, which proves that the uniformity of the refined calibration

samples is good again.

Step 3: ICP fixed value of yttrium content in steel

Through the uniformity test in step 2, four samples were taken out from each steel

plate from Z Ito Z8, and one of the four samples with the best uniformity was selected as

the standard sample of the numbered steel plate, and eight standard samples respectively

correspond to Z1 to Z8. Drilling cuttings were sampled at a quarter of the standard samples (pay attention not to over-high bit temperature during sampling), and 0.50g of steel cuttings was taken, add 25mL mixed solution of water-hydrochloric acid-nitric acid

(1: 1: 3) and slowly heat it until the sample is completely dissolved, add 5mL perchloric

acid, heat it to smoke with perchloric acid, and continue heating until the volume of the

test solution remains 1 ml ~ 2 ml. Cool, add 20mL of water and 5mL of hydrochloric

acid, dissolve the salts with slight heat, and cool to room temperature, when the test

solution is clear and free of impurities. The obtained standard solutions correspond to

steel plates Z1-Z8 one by one, and the standard solutions are numbered X1, X2, X3, X4,

X5, X6, X7 and X8.

The yttrium content in standard solution was determined by ICP-AES, and the

standard solution was used to calibrate ICP-AES, and the sample was determined under

the condition of good accuracy and stability of ICP-AES. The content of yttrium in steel

samples from ZI to Z8 can be obtained by detecting the standard solution (X1

corresponds to the content of yttrium in steel samples from Z1, and so on). The yttrium

content measured by ICP-AES is shown in table 4.

Table 4 yttrium content in standard solution measured by ICP-AES Standard X1 X2 X3 X4 X5 X6 X7 X8 solutionNo. Yttrium content 0.0023 0.0024 0.012 0.01 0.021 0.042 0.062 0.075 (wt/%)

Step 4: Drawing the standard analysis curve

Use the working spectral lines screened in step 2 to excite each standard sample

respectively, use SPECTROLAB S spark direct reading instrument to excite and calibrate

the standard samples with different rare earth yttrium content, establish a database corresponding to the intensity ratio and rare earth yttrium content in the spectrometer, as shown in Table 5, and perform linear fitting on the data to form a rare earth yttrium standard analysis curve (see Figure 2), thus realizing accurate customization of the standard spectral lines.

The mathematical model of yttrium is: y=1.94724*108

x 2+3.16856*10 7 x+89329.93426

Table 5 Corresponding relationship between intensity ratio measured by Spectrolab S spark direct reading instrument and rare earth yttrium concentration Sample Zi Z2 Z3 Z4 Z5 Z6 Z7 Z8 No. strength 145177 160860 511194 457703 833727 1713390 2864766 3533816 ratio

Content% 0. 0023 0. 0024 0. 012 0.01 0.021 0.042 0.062 0.075

Example 2

Eight points were randomly selected from yttrium-bearing steel, and dot scanning

was performed by full spectrum spark direct reading spectrometer. Set the working

conditions of full spectrum spark direct reading spectrometer: discharge frequency

400Hz. The argon flow rate is 2201/h. Environmental temperature 25°C/ light room

temperature 20°C, humidity 50-60%, purging time is Is. The excitation time is 12s and

the precombustion time is 4s. Dot scanning is performed on the surface of the sample by

using a spark direct reading spectrometer to obtain the intensity ratio, and the yttrium

content in the sample is calculated according to the standard analysis curve obtained in

step 4 of Example 1.

The intensity ratio measured by dot scanning of full spectrum spark direct reading

spectrometer is 410040, and the mathematical model of yttrium introduction is: y=1.94724*10 8 x 2+3.16856*10 7 x+89329.93426, and the yttrium content is

0.00956%.

Determination of yttrium content by ICP-AES: adopt the above yttrium-containing

steel, sample the drill cuttings at 1/4 of the sample of yttrium-containing steel (pay

attention to the bit temperature not to be too high during sampling), take 0.50g sample of

steel cuttings, add 25mL mixed solution of water-hydrochloric acid-nitric acid (1: 1: 3)

and slowly heat it until the sample is completely dissolved, add 5mL perchloric acid, heat

it to smoke, and continue heating until the volume of the test solution remains 1. Cool,

add 20mL of water and 5mL of hydrochloric acid, dissolve the salts with slight heat, and

cool to room temperature, when the test solution is clear and free of impurities. The

yttrium content in the sample solution to be tested was determined by ICP-AES, and the

standard solution was used to calibrate ICP-AES. When the accuracy and stability of

ICP-AES were good, the yttrium content in the steel sample to be tested was 0.0087%.

Example 3

500Hz. The argon flow rate is 2301/h, environmental temperature 25°C/ light room

temperature 20°C,humidity 50-60%, purging time is Is. The excitation time is 12s and the

precombustion time is 4s. Dot scanning is performed on the surface of the sample by

step 4 of Example 1.

spectrometer is 265096, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2+3.16856*10 7 x+89329.93426, and the yttrium content is

0.00537%.

Determination of yttrium content by ICP-AES: use the above steel, sample the drill

cuttings at 1/4 of the yttrium-containing steel sample to be measured (during sampling,

pay attention to the bit temperature not to be too high), take 0.50g of steel cuttings, add

mL of mixed solution of water-hydrochloric acid-nitric acid (1: 1: 3) and slowly heat it

until the sample is completely dissolved, add 5mL of perchloric acid, heat it to smoke,

and continue heating until the volume of the test solution remains 1 ml. Cool, add 20mL

of water and 5mL of hydrochloric acid, dissolve the salts with slight heat, and cool to

room temperature, when the test solution is clear and free of impurities. The yttrium

content in the sample solution to be tested was determined by ICP-AES, and the standard

solution was used to calibrate ICP-AES. When the accuracy and stability of ICP-AES

were good, the yttrium content in the steel sample to be tested was 0.0053%.

Example 4

420Hz. The argon flow rate is 2201/h, environmental temperature 25°C/ light room

using a spark direct reading spectrometer to obtain the intensity ratio, and the yttrium content in the sample is calculated according to the standard analysis curve obtained in step 4 of Example 1.

spectrometer is 707314, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2 +3.16856*10 7 x+89329.93426, and the yttrium content is 0.0176%.

were good, the yttrium content in the steel sample to be tested was 0.017%.

Example 5

440Hz. The argon flow rate is 2301/h, environmental temperature 25°C/ light room

the precombustion time is 4s. Dot scanning is performed on the surface of the sample by using a spark direct reading spectrometer to obtain the intensity ratio, and the yttrium content in the sample is calculated according to the standard analysis curve obtained in step 4 of Example 1.

spectrometer is 1065743, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2 +3.16856*10 7 x+89329.93426, and the yttrium content is 0.0265%.

were good, the yttrium content in the steel sample to be tested was 0.0274%.

Example 6

460Hz. The argon flow rate is 2201/h, environmental temperature 25°C/ light room

temperature 20°C, humidity 50-60%, purging time is Is. The excitation time is 12s and the precombustion time is 4s. Dot scanning is performed on the surface of the sample by using a spark direct reading spectrometer to obtain the intensity ratio, and the yttrium content in the sample is calculated according to the standard analysis curve obtained in step 4 of Example 1.

spectrometer is 2013699, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2 +3.16856*10 7 x+89329.93426, and the yttrium content is 0.0471%.

were good, the yttrium content in the steel sample to be tested was 0.045%.

Example 7

480Hz. The argon flow rate is 2301/h, environmental temperature 25°C/ light room temperature 20°C, humidity 50-60%, purging time is Is. The excitation time is 12s and the precombustion time is 4s. Dot scanning is performed on the surface of the sample by using a spark direct reading spectrometer to obtain the intensity ratio, and the yttrium content in the sample is calculated according to the standard analysis curve obtained in step 4 of Example 1.

spectrometer is 2211772, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2 +3.16856*10 7 x+89329.93426, and the yttrium content is 0.051%.

were good, the yttrium content in the steel sample to be tested was 0.0492%.

Example 8

450Hz.The argon flow rate is 2251/h, environmental temperature 25°C/ light room

step 4 of Example 1.

spectrometer is 389,569, and the standard analysis curve of yttrium is:

y=1.94724*10 8 x 2+3.16856*10 7 x+89329.93426, and the yttrium content is

0.00898%.

were good, the yttrium content in the steel sample to be tested was 0.0091%.

The measured values (spark direct reading measured values) of the method

according to the present invention in Examples 2 to 8 were compared with the detected results (ICP measured values) of the ICP measuring method, and the results are shown in

Table 6.

Table 6 Comparison of test results

ICP estimated Spark direct Deviation Deviation Y value wt% reading measured value wt% rate

% value wt%

Example2 0.0087 0.00956 0.00086 0.098850575 Example 0.0053 0.00537 0.0000700 0.013207547 Example4 0.017 0.0176 0.0006 0.035294118

Example5 0.0274 0.0265 -0.0009 0.032846715

Example 0.045 0.0471 0.0021 0.046666667

Example7 0.0492 0.051 0.0018 0.036585366

Example8 0.0091 0.00898 -0.00012 0.013186813

At present, the determination of yttrium content mainly adopts ICP method, but the

process of detecting yttrium content by this method is very complicated, and destructive

detection is needed for the sample to be detected, which takes a long time. It can be seen

from Table 6 that compared with ICP method, the deviation value of the method of the

present invention is very small, which is basically negligible. However, the detection

method of the invention does not need to destroy the sample to be detected, and the

detection speed is fast. And is suitable for popularization and application.

Test example: uncertainty test

The uncertainty analysis was carried out on the detection results of Examples 2-8.

Uncertainties are mainly divided into two categories: Class A uncertainty and Class

B uncertainty. By calculating the uncertainty, the influencing factors of the determination

results are determined.

1. uncertainty caused by test results ((U(rel,Al)))

Reference formula (2.1) for calculating standard uncertainty and relative standard

uncertainty introduced by repetitive test

U(rei,A1)=-: (2.1)

Table 7 Relative standard uncertainty of repeatability test of y

Y Example2 Example3 Example4 Example5 Example6 Example7 Example8 average value 0.009560 0.005370 0.017600 0.026500 0.047100 0.051000 0.008980 S 0.000173 0.000747 0.000316 0.000469 0.000200 0.000300 0.000200 U(A,1) 0.000061 0.000264 0.000112 0.000166 0.000071 0.000106 0.000071 U(A,1)averag 0.000121 e value Urel(A,1) 0.006386 0.049198 0.006352 0.006255 0.001501 0.002080 0.007874 Urel(A,1)aver 0.011378 age value

According to the analysis in Table 7, the uncertainty calculated by repetitive test is

0.0001. The smaller the uncertainty, the smaller the deviation value of the measured

results, the better the test accuracy and the higher the use value of the values. The

uncertainty of yttrium is only 0.0001, and the uncertainty values are all small, which

shows that the measurement results are of good quality and high reliability.

2. Uncertainty brought by steel matrix(U(rel,B))

It is known that the content of each element in steel is based on iron matrix as

internal standard. In the testing process, the content of iron matrix in the calibration

sample and the sample to be tested should be the same or basically the same. The

difference of iron matrix content between the sample to be tested and the calibration

sample will bring uncertainty to the measurement results. Generally, the difference of

iron matrix content between the calibration sample and the sample to be tested is not

more than 1% (according to experience, every 1% difference in iron matrix content will bring about an error of 0.3), and the standard uncertainty caused by evenly distributed iron quantity difference is as follows:

According to the determination of content analysis, assuming that the average

concentration of iron is 98%, then

0.3 UB1 0.18 (1)

Urei,B1 0.0018 98 (2)

According to the analysis, the uncertainty of yttrium caused by steel matrix is

0.0018.

Evaluation of synthetic uncertainty (Urei)

The uncertainty brought by different reasons is judged by the uncertainty brought by

the test results, the uncertainty brought by the nonlinearity of calibration spectral lines

and the uncertainty brought by steel matrix, and the whole experimental test results are

judged by calculating the combined uncertainty. The calculation process is as follows:

Urei = Urei,A1 2 + UreIB1 2 (3)

Table 9 Evaluation of Synthetic Uncertainty Y Al/wt% 0.000121 Bi/wt% 0.001800 Urel/wt% 0.001804

The measurement result is judged by calculating the uncertainty of class a and class

b. If the confidence level of 95% is taken, then the factor k=2 is included, then in the test

sample:

UYttrium=. 001804 X 2=0. 003608 (4)

According to the above formula, the uncertainty of yttrium is 0.003608, that is, the

fluctuation range of yttrium detection results is 0.003608%.

In an embodiment, the deviation values of the values measured by ICP-AES and full

spectrum spark direct reading spectrometry are 0.00086, 0.00007 and 0.0006,

respectively, and the deviation rates are all less than the uncertainty of yttrium

(0.003608), so it can be concluded that the accuracy of the values measured by full

spectrum spark direct reading spectrometry is better and meets the detection

requirements.

The above is only a preferred embodiment of this application, and is not used to

limit this application. For those skilled in the art, this application can be modified and

varied. Any modification, equivalent substitution, improvement, etc. made within the

spirit and principle of this application shall be included in the protection scope of this

application.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1.Method for quickly determining yttrium content in steel by using full spectrum

spark direct reading spectrometry, which is characterized by comprising the following

steps:

(1) By changing the addition amount of rare earth yttrium, steel ingots with different

yttrium contents are refined and rolled into billets.

interference of elements, carrying out uniformity detection on the samples by using the

best working spectral line, and selecting the sample with the best uniformity as a standard

sample.

AES;

is detected by using the standard analysis curve of rare earth yttrium.

2. The detection method according to claim 1, characterized in that in step (1), the

billet is prepared by the following method:

SO. a magnesium oxide crucible is built in a medium frequency induction furnace,

baked and washed with matrix raw materials; The addition amount of matrix raw

materials and rare earth yttrium is determined by proportioning calculation, and the raw

materials are polished, weighed and put into a magnesium oxide crucible;

at 6.67x10-1 Pa. When the matrix raw materials are completely melted, rare earth yttrium

is added, the temperature is kept, electromagnetic stirring is carried out, melted, poured

into a casting mold, forged after demoulding, and rolled into a billet with a thickness of

mm.

3. The detection method according to claim 2, wherein in step SO1, the purity of the

rare earth yttrium is 99.9%.

4. The detection method according to claim 2, characterized in that, in step SO1, the

matrix material consists of the following chemical components by mass fraction:

C 0.09%, Mn 1.34%, S 0.006%, P 0.021%, Si 0.2%, Als 0.027%, N 0.0044%, Nb

0.029%, Ca 0.0013%, Ti 0.011%, Sn 0.0044% and the balance is Fe.

5. The detection method according to claim 1, which is characterized in that, in step

(2), sampling is carried out according to the method specified in GB/T20066-2006, and

the surface of the sample is ground after sampling, and the particle size of the ground

material is 0.124-0.25 mm.

6. The detection method according to claim 1, which is characterized in that in step

(2), the working conditions of the full spectrum spark direct reading instrument are as

follows: the discharge frequency is 400-500 Hz. The argon flow rate is 220-2301/h, environmental temperature 25°C/ light room temperature 20°C, humidity 50-60%.

7. The detection method according to claim 1, characterized in that, in step (2), the

uniformity detection is as follows: spot scanning is performed on the surface of the

sample by using a full spectrum spark direct reading spectrometer, 8 spots are made for

each sample, and the uniformity of the sample is judged by the relative standard

uncertainty of the intensity ratio.

8. The detection method according to claim 1, characterized in that in step (2), the

best working spectral line isXY=371.029nm.

9. The detection method according to claim 1, characterized in that in step (3), the

standard solution is prepared by the following method:

Al. Take 0.50g of steel scrap and add 20mL of hydrochloric acid solution with a

density of 1.19g/mL. After the steel scrap is completely dissolved, add 5 drops of

perchloric acid with a density of 1.67g/mL, heat until the perchloric acid smokes

completely, and continue heating until the volume of the test solution remains 1-2 ml.

A2. Cool the test solution, dilute it to constant volume, mix well, and then let it

stand until the test solution is clear and free of impurities, thus obtaining the standard

solution.

10. The detection method according to claim 1, characterized in that in step (4), the

mathematical model is y=1.94724*10 8 x 2 +3.16856*107 x+89329.93426, where x is the

element content, y is the intensity ratio.