Trace Elements In Steel Research Articles

Rapid online analysis of trace elements in steel using a mobile fiber-optic laser-induced breakdown spectroscopy system

A mobile fiber-optic laser-induced breakdown spectrometer (FO-LIBS) prototype was developed to rapidly detect a large quantity of steel material online and quantitatively analyze the trace elements in a large-diameter steel tube. Twenty-four standard samples and a polynomial fitting method were used to establish calibration curve models. The R2 factors of the calibration curves were all above 0.99, except for Cu, indicating the elements’ strong self-absorption effect. Five special steel materials were rapidly detected in the steel mill. The average absolute errors of Mn, Cr, Ni, V, Cu, and Mo in the special steel materials were 0.039, 0.440, 0.033, 0.057, 0.003, and 0.07 wt%, respectively, and their average relative errors fluctuated from 2.9% to 15.7%. The results demonstrated that the performance of this mobile FO-LIBS prototype can be compared with that of most conventional LIBS systems, but the more robust and flexible characteristics of the FO-LIBS prototype provide a feasible approach for promoting LIBS from the laboratory to the industry.

Effect of laser wavelength and energy on the detecting of trace elements in steel alloy

In order to investigate the effect of laser wavelength and energy on the detection of the trace elements in alloy steel, pulsed laser at 1064 nm and 532 nm wavelength have been employed to generate plasma. The effects of the laser energy of these two laser wavelengths on plasma emission intensity, plasma temperature and electron density were studied. The trace elements of Ni, Al and Cr in the sample were quantitatively analyzed by internal standard method under these two different laser wavelengths with different laser energies. The results have shown that the intensities of the spectral intensities increased with the increasing of laser energy at different wavelengths, and then tended to change gently. The plasma temperature also increased with the increasing of laser energy, and the change of plasma temperature under 532 nm wavelength is slower. The plasma electron density firstly increased with laser energy, and then decreased when the laser energy exceeded the threshold. The quantitative analysis results show that the elements of Ni and Al have lower detection limits at 1064 nm wavelength, while the lower detection limit of Cr corresponding to the 532 nm wavelength. When the sample was ablated at 1064 nm wavelength, the detection limit of the three elements was gradually reduced with the increasing of laser energy.

非金属元素分析のためのヘリウム大気圧マイクロ波プラズマ発光分光分析法

The accurate determination of trace elements in steel is an important and challenging task in analytical chemistry. The variation of the contents of nonmetal elements such as C, P and S in steel can have a significant influence on the mechanical and physical properties. A sensitive and accurate method for the determination of these elements in steels is therefore required.The aim of the present work is to develop an accurate method using He-MIP AES (Helium Microwave-Induced Plasma Atomic Emission Spectrometry) to determine the trace amounts of these elements in the gas, liquid and solid samples. The optimization of the He-MIP AES technique and its analytical figures of merit, as well as its application to the determination of these elements in the samples, were described. The samples were transported and excited in a microwave induced helium plasma operated at atmospheric pressure.A high-power (∼1000 watt CW, 2.45 GHz) annular-shaped microwave-induced helium plasma (He-MIP) was developed for the determination of nonmetals in the aqueous solutions, and the characteristics were presented. The plasma was generated at atmospheric pressure by an Okamoto cavity of the surface wave mode. No external cooling was used to stabilize the plasma. The electron density and iron-excitation temperature were on the order of 1014/cm3 and 6500K, respectively. An air for gas sample was aspirated with an aspirator and introduced directly into the He-MIP. Carbon (247.9 nm) in the air was detected. An aqueous solution was injected into the plasma by an ultrasonic system with desolvation and condensation. Introduction of aqueous fluoride in the form of NaF, chloride in the form of NaCl and bromide in the form of KBr produced intense emission and detection limits of 100 ppb for FI (685.6 nm), Cl II (479.5 nm) and 150 ppb for Br II (470.5 nm) were obtained. Detection limits of the carbon and phosphorous in the aqueous solution were 1 ppb and 2 ppb, respectively.

水素化物生成-高出力窒素マイクロ波誘導プラズマ発光分光分析による鉄鋼中の微量元素の定量

水素化物生成-高出力窒素マイクロ波誘導プラズマ発光分光分析による鉄鋼中の微量元素の定量

鋼中微量成分分析のための試料前処理技術

鋼中微量成分分析のための試料前処理技術

High Power Nitrogen Microwave Induced Plasma for the Determination of Some Trace Elements in Steels by Atomic Emission Spectrometry with Hydride Generation Technique

An annular-shaped high power nitrogen microwave induced plasma (N 2 -MIP) sustained at atmospheric pressure by an Okamoto cavity has been used as a new excitation source for atomic emission spectrometry (AES). In the preliminary study of high power N 2 -MIP-AES, the background equivalent concentrations and detection limits for a number of elements were measured at the most sensitive wavelengths of the elements by using a conventional solution nebulization as a sample introduction method. The detection limits obtained for the elements of interest are inferior by approximately one to two orders of magnitude compared with those obtained in this laboratory by a conventional argon inductively coupled plasma atomic emission spectrometry with solution nebulization. Subsequently, the combination of high power N 2 -MIP-AES with continuous-flow hydride generation technique was examined for the sensitive determination of such hydride-forming elements as antimony, arsenic, selenium and tellurium. Under the optimized experimental conditions, the best attainable detection limits at Sb(I)217.581, As(I)228.812, Se(I)196.026 and Te(I)214.281 nm by use of N 2 -MIP-AES coupled with hydride generation were 4.46 ngSb/ml, 2.99 ngAs/ml, 0.86 ngSe/ml and 15.0 ngTe/ml with linear dynamic ranges of three to four orders of magnitude in concentrations. After the interference study, the present method has been applied to the determination of trace concentrations of the above-mentioned hydride-forming elements in several steel standard reference materials issued by The Japan Iron and Steel Federation. The results obtained by the proposed method were in good agreement with the certified values.

"Why do we Need to Measure Trace Elements in Steel ?"

With the increase in performance requested by users in the last twenty years, steel makers have had to improve their melting operations dramatically. Numerous chemical elements are now controlled or eliminated at levels of 50 ppm and below.Sinces it is difficult to give a rating to the importance of these elements, this paper lists a series of them alphabetically, and comments on them, non-exhaustively. Control of these substances has led to improvements in : - Mechanical characteristics at room and elevated temperatures, as well as creep resistance. - Toughness and fracture mechanics at low temperature. - Practical weldability - Hot and cold formability - Corrosion resistance in numerous media.

Simultaneous multi-element analysis of solid samples by laser ablation—microwave-induced plasma optical emission spectrometry

An experimental arrangement for multi-element microanalysis of solid samples by laser ablation-microwave-induced plasma optical emission spectrometry is introduced. The application of optical fibres as the interface between an échelle spectrograph and a gateable optical multi-channel detector head allows simultaneous measurements of up to ten elements with single laser shots and investigations of element correlation in samples from shot to shot. Correlation measurements of trace elements in steel and aluminum and sodium and lithium in high-purity quartz are given as examples.

Determination of trace elements in steel by laser ablation inductively coupled plasma mass spectrometry.

A rapid quantitative analysis of the trace elements in steel by laser ablation inductively coupled plasma mass spectrometry is described. The conditions for laser ablation and normalization methods to improve the analytical precision are given. The optimum conditions for laser ablation were achieved when the ion yield was a maximum at the focus position in the fixed Q pulse mode, and above the focus position in the Q-switched pulse mode. It was found that the fixed Q pulse mode was most suitable for the determination of trace metal elements in steel, and that the Q-switched pulse mode was most suitable for both non-metallic elements and elements with a high boiling-point. In order to improve the analytical precision for those elements with a strong background intensity, normalization methods with both the matrix ion, 57Fe+, and 38Ar+ are proposed.

Mg程度の試料を用いた溶液法の黒鉛炉原子吸光法による鋼中の微量元素定量

mg程度の試料を用いた溶液法の黒鉛炉原子吸光法による鋼中の微量元素定量

An Automatic Hollow-Cathode Light Source Device for Emission Spectrochemical Analysis

Abstract The construction and operation of the ZKG-I automatic hollow-cathode hight source device for the emission spectrochemical analysis of trace elements in steels, superalloys, nonferrous metals and super-high-purity substances are presented in this booklet. The questions discussed include high voltage electrical source unit for steady current and steady voltage supply, dynamic equilibrium-type vacuum system, programme control unit of the light source, and the comparison of the effect of He and Ar to be used as carrier gas in the hollow-cathode lamp on the limit of detection for different elements. The different methods for the detection of trace elements in superalloys, super-high-purity substances, pure metals, and oxides of pure metals are also listed.

Rapid determination of lead, bismuth, antimony and silver in steels by flame atomic absorption spectrometry combined with flow injection analysis

A procedure based on pulse-nebulization flame atomic absorption spectrometry (a.a.s.) is shown to give considerably lower detection limits than conventional flame a.a.s. for the direct determination of trace elements in steels, because more concentrated sample solutions can be aspirated. Optimum conditions with respect to injected sample volume, total salt concentration in sample solution, (i.e., dilution factor) and selected resonance wavelengths were investigated. Results for a variety of low and high alloy steels are presented. The detection limits in the solid steel were as follows: Pb 2.5, Bi 2.5, Sb 10 and Ag 0.3 μg g −1.

Demountable double-chamber hollow-cathode lamp: a new approach to the determination of trace elements in steel

A new type of excitation source for emission spectrochemical analysis of steel has been constructed and studied. The source is a water-cooled demountable hollow-cathode lamp; a tubular sample forms the cathode and can be sputtered from both ends. This yields very low detection limits. The detection limits for the elements studied, aluminium, arsenic, boron, calcium, cobalt, chromium, manganese, molybdenum, niobium, nickel, lead, silicon, tin, titanium and tungsten, were found to be below 1 µg g–1(except for cobalt and silicon). It was also found that the lamp could be used to determine concentrations of up to several per cent. for some elements and the relative standard deviations were in the range 1–3%. The lamp makes a very interesting complement to the instrumental techniques normally used in steel analysis, X-ray fluorescence and spark source optical emission spectrometry, as the suitability of these for the determination of trace elements is limited.

The Use of a High Temperature Hollow Cathode Lamp for the Determination of Trace Elements in Steels, Nickel-Base Alloys, and Ferroalloys by Emission Spectrometry

A high temperature hollow cathode lamp from Applied Research Laboratories, Luton, was used for multielement determination of trace elements in steels, nickel-base alloys and ferroalloys. A 10-mg sample (chips) was placed inside a hollow graphite electrode in the lamp, which was filled with helium. It was possible to raise the power through the lamp linearly and automatically, so that the combined thermal and sputtering effect in the lamp atomized the different elements one after another according to their boiling points. This selective volatilization improved the precision and the limits of detection for the elements determined. Analysis results for Pb, Bi, Zn, Ag, Sb, and Ca in the concentration range 0.05 to 100 μg g−1 are discussed. Because of the effective atomization in the lamp, no matrix effects were observed for these elements. One of the main purposes of this investigation was to study the time dependence of the intensity for the different elements during the volatilization phase. This procedure gave very clean spectra. In this investigation a new computerized image dissector echelle spectrometer, was used as the registration system.

A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. V. Determination of Minor Constitutents and Trace Elements in Steel

Abstract The applicability of the modified hollow cathode emission source to the determination of some elements usually contained in steel was tested in the case of chromium (0.144 – 3.07%), copper (0.090 – 0.49%), manganese (0.016 – 1.42%), molybdenum (0.007 – 1.41%), nickel (0.048 – 5.15%, silicon (0.013 – 0.81%), and vanadium (0.034 – 0.64%). The linearity of the calibration curves was found to be highly satisfactory, the Bravais - Pearson correlation coefficient ranging from 0.97 to 0.99. Moreover, results showed that background intensity is negligible and that blackening values can be plotted without resorting to internal standards or other preliminary corrections.

Effects of several experimental parameters on the relative sensitivity factors in spark-source mass spectrometric analysis of steel

The effects of spark gap, sample electrode size, spark technique, spark position, and energy-pass bandwidth of the ion beam, on the relative sensitivity factors in analysis for trace elements in steel by spark-source mass spectrometry have been investigated by means of electrical-detection, peak-switching techniques. The effects of spark gap and spark position are of the greatest importance. The energy distributions of both matrix and impurity ions were measured. For several elements, changes in spark position produced corresponding changes in the distribution of ion energies. These changes of energy distribution were partly responsible for variations in relative sensitivity factors with changing spark position.

Application of the Mass Spectrometry to the Analysis of Trace Elements in Steels (1st Report)

Aiming at improving of the precision in analyzing trace elements in steels by a r-f spark source mass spectrography an investigation about measuring conditions was made.The repetition frequency gives remarkable influence to the ion intensity and it is desirable to fix the frequency.In order to take a photo of a spectrum of low exposed amount it is effective to use an ion-beam chopper making the repitition frequency fixed.In a narrow range, the influence of accelerating voltage makes little difference. And the precision is favorable under a condition of a good focusing.It was presumed that the time fluctuation of ion intensity depended upon measuring errors of a beam monitor, variety of plates etc. and not upon the separating distilling.

The use of a high temperature hollow-cathode lamp for the spectrographic analysis of steels, high temperature alloys and related materials for trace elements

A study has been made of factors affecting the operation of high temperature hollow-cathode lamp discharges for the emission-spectrographic determination of trace elements in steels, high temperature alloys and related materials. The factors studied include electrode geometry, carrier-gas pressure and exposure times. The effect of these parameters on element sensitivity and the precision of analysis is discussed.The analysis of dissimilar alloy types has been shown to present problems associated with inter-element effects, and the magnitude of these effects is illustrated. A simple method for overcoming inter-element effects is described, involving the addition of silicon as a buffer to both samples and standards. Results by this method for the analysis of a wide variety of materials from calibration graphs based on a single set of synthetic powder standards are presented. It is possible by this technique to obtain quantitative trace-analysis results without the necessity of providing chemically analysed standards.

Some Problems on the Spectrochemical Analysis of Trace Elements in Steel (Using D.C.Arc Technique for Powdered Samples)

Application of the D-C Arc Method to the emission spectrographical analysis for powdered samples gives good results in controlling the amount of trace elements in steel.Exam nation of the analytical conditions, pre-treatments of the samples and selective volatilizations was found necessary as the results of th's study.The deviations in the contents of Si (0.001-0.02%) and Pb (0.0001-0.01%) were both less than 10%.

A chemical-spectrographic procedure for determination of some trace elements in steel and nickel-base alloys

A chemical-spectrographic procedure, which involves three steps, is proposed for determining certain residual metals in steel and nickel-base alloys: (1) Dissolve the sample with a suitable acid mixture. (2) Separate the iron, chromium or nickel from the residuals by a mercury-cathode electrolysis. (3) Analyse the resulting concentrated residuals in a solution form by the rotating-disk spectrographic technique. Cobalt serves as the internal standard. Metals containing 0.003-0.10% of aluminium, calcium, vanadium and titanium can be determined accurately and rapidly with this procedure. Eight samples in duplicate may be analysed for the above elements in 12 hr.