Foreword

By analyzing the composition of metal materials, we can deeply understand the reasons and laws of the performance of metal materials. Because of the differences in crystal structure and bonding between atoms of various components of metal materials, their performances are different. Only by deeply understanding the composition of the metal material can the metal material be processed correctly. On the basis of clarifying its composition, the most suitable processing method for this metal material can be found through theoretical knowledge and production practice. Correct metal processing methods can not only do more with less, but also fully guarantee the performance of metal materials. After selecting the correct metal processing method, the processed metal material must also be heat treated. Heat treatment of metal materials can not only remove defects in the processing link, but more importantly, significantly improve the properties of metal materials. In short, the correct analysis of the composition of metal materials can not only give full play to the performance of materials, but also reduce production costs and maximize economic benefits.

Traditional method

2.1 Spectrophotometry
Spectrophotometry is the most common method in traditional metal material analysis methods, and this method has a complete legal basis. Through qualitative and quantitative observation, calculate the luminous intensity or absorbance of the measured substance in a certain wavelength range or specific wavelength to determine the composition of the metal material. In the experiment, a spectrophotometer was used to uniformly and continuously irradiate light with different wavelengths into a solution. This solution is not suitable for any solution, it has certain specificity in concentration. The composition of the metal material can be qualitatively obtained by observing the intensity of the corresponding absorption at different wavelengths.

2.2 Titration analysis method
Titration analysis method is a relatively convenient and fast method to analyze the composition of metal materials. The principle of this method of analyzing the composition of metal materials is by adding a standard solution of known precise concentration to the solution to be measured. Until the substance to be tested and the solution of known precise concentration fully react according to the stoichiometric unit. When the reaction is complete, record the volume of the standard solution of known concentration consumed, and find out the relevant amount of the standard solution to obtain the content of the substance to be tested. This method can still accurately and quickly analyze the composition of metal materials.

2.3 Atomic Spectroscopy
Atomic spectroscopy can be divided into atomic absorption spectroscopy and atomic emission spectroscopy, which is a traditional technique for analyzing the composition of metal materials. The principle of atomic absorption spectrometry to analyze the composition of metal materials is to quantitatively analyze the content of the measured element by the absorption intensity of the outer electrons of the ground state atoms to the corresponding atomic resonance radiation of visible light and ultraviolet light in the gaseous state. This measurement method is especially suitable for the absorption of light radiation by gaseous atoms, and has the advantages of high sensitivity, strong anti-interference ability, strong selectivity, wide analysis range and high precision. Of course, this method also has its drawbacks, and it cannot analyze multiple elements at the same time. The unsatisfactory aspect is that the sensitivity of the determination of refractory elements is not high, and the effect of measuring some complex samples is not satisfactory. Atomic emission spectroscopy is one of the oldest methods for analyzing the composition of metallic materials by spectroscopy. The principle of this method is that the ions or atoms of each element have the characteristic of emitting special electromagnetic radiation under electrical or thermal excitation. This method uses the emissive to carry out qualitative and quantitative elemental analysis. It can measure multiple elements at the same time, so that the measurement purpose can be achieved with less sample consumption, and the measurement results can be obtained quickly. Generally, the whole batch is tested. This method is used for samples, but its fatal disadvantage is poor accuracy, and it can only detect the composition of metallic materials, and it is helpless for most non-metallic compositions.

2.4 X-ray fluorescence spectroscopy
X-ray fluorescence spectrometry is mostly used to determine metal elements, and it is also a relatively traditional method for determining the composition of metal materials. Its principle is: the ground state atoms will be in a low-energy state when they are not excited, and once excited by a certain frequency of radiation, they will become a high-energy state, and they will emit fluorescence in a high-energy state. The wavelength of this fluorescence is very special. The element species of the sample can be determined by the wavelength of these X-ray fluorescence lines. After the element type is determined, the spectral line intensity of the standard sample is used as a reference to compare the spectral line of the tested sample, that is, the definite and accurate content of the sample element can be obtained. The method of X-ray fluorescence spectrometry to determine the composition of metal materials is widely used in water quality monitoring, environmental science, minerals, medical analysis, biological products and so on.

In pressure pipeline engineering, the methods of 2.3 and 2.4 are commonly used for material analysis (remarks by pressure pipeline personnel).

2.5 Electroanalysis
Electroanalysis is also a traditional metal material composition analysis method. Originally this method was only to explore the chemical reactions that take place in metal batteries, it was later used to determine the composition of metal materials. The principle it is based on is the correlation between the electrical properties and composition content of metal materials, but compared with other methods for analyzing the composition of metal materials, this method gradually withdraws from the historical stage due to the difficulty of implementation and the high error of interference.

New traditional method

3.1 Laser-induced plasma spectroscopy
The analysis of metal material composition by laser-induced plasma spectroscopy does not need to be carried out on complex equipment, and the equipment requirements are not high, so the investment will not be very high. The advantage of this method is that it can measure multiple elements at the same time, so it has higher efficiency, and this method is often used to determine the types of elements in stainless steel. The narrow range of use is the only disadvantage of the laser-induced plasma spectroscopy method.

3.2 Inductively coupled plasma mass spectrometry
The development of this method began in the 1970s, and its principle is to analyze isotopes and inorganic elements in materials to analyze the composition of metal materials. The specific process is: inductively coupled plasma will ionize at high temperature. The advantage of mass spectrometer is very significant, it can achieve the purpose of fast and sensitive scanning. Using an interface technology, these two characteristics are skillfully combined to form a unique analysis technology. This analytical technique is most widely used for precious, refractory and rare metals. The advantages of inductively coupled plasma mass spectrometry are high sensitivity, simple operation, fast determination process, and high accuracy; the disadvantage is that the cost of using this method will be quite high, so this method is mostly used in relatively special metals.

3.3 Graphite Furnace Atomic Absorption Spectrometry
Graphite furnace atomic absorption method is also a new type of metal material composition analysis method. Its principle is to determine the metal material composition by detecting the types of atoms adsorbed by special graphite. The atomization instruments used in this method are made of special graphite materials, and there are special requirements for the shape of these instruments, which are processed into a cup-like or tubular shape to increase the contact area. Because the sample components are atomized and the dilution of atomic concentration is avoided during the measurement process, this method has high sensitivity and is widely used in its application fields, especially for the analysis of solid samples and small amounts of samples. .

Epilogue

This paper mainly discusses the methods of metal material composition analysis, starting from two aspects of traditional methods and new methods, and introduces many kinds of metal material composition analysis methods in detail. In these methods, the high importance of science and technology is everywhere. The application of science and technology not only improves the accuracy of metal material composition analysis results, but also improves its efficiency. At the same time, we should also be soberly aware of the lack of efficiency and accuracy of the existing metal material composition analysis methods, and continue to explore new technical means for metal material analysis from these two aspects.