The chemical composition of railway fasteners is very important, so in most cases, chemical composition is the acceptance index. The chemical composition also determines the mechanical properties and defects of the fastener. For example, the residual magnesium content in the grey iron fastener is less than 0.03%, and the casting of grey iron will inevitably be affected, resulting in the defects of poor spheroidization. The results of sampling and testing are analyzed in different ways. Non-ferro-alloy rail fasteners, and high-alloy steel fasteners, special cast iron fasteners and high-temperature alloy fasteners requiring special performance are generally accepted as one of the technical conditions. Dozens of alloy chemical components do not as acceptance technical conditions of fasteners, in order to guarantee the quality of fasteners, fasteners factory should also check and control the chemical components of alloy in the production process. Chemical analysis of building fasteners is generally divided into inspection of furnace money and final inspection of finished fasteners. Before furnace inspection usually adopts thermal analysis, ultrasonic, spectrometry, gas rapid analysis method such as quick analysis method and corresponding equipment, can be in a few minutes for rapid determination of the main ingredient in casting alloy liquid or casting alloy sample elements, impurity elements and dissolved gas content, or the yuan to casting alloy specimen fast quantitative analysis.
For example, the continuous cooling curve of the thermal analysis specimens that can be cast in different places is adopted by thermal analysis. The carbon and silicon content and carbon equivalent in cast iron are measured. X-ray fluorescence spectrophotometry can be used to analyze the chemical composition of the sample. The whole process, from pouring the sample to printing the analysis results, takes only a few minutes.The content of hydrogen, oxygen, nitrogen and other gases dissolved in the alloy solution can be rapidly analyzed by using hydrogen meter, oxygen meter and nitrogen meter. Finished product chemical analysis methods mainly include: construction fasteners titration method, chromatography, decomposition method, volumetric method and gravimetric method, potential method, power method, point method, colorimetric method, luminescent analysis, photometric method, spectrophotometry, spectrometry, mass spectrometry, chromatography, microprobe analysis, diffraction analysis, thermal analysis and gas analysis, etc.