Railway fasteners a century of development, the use of what part even more than a lifetime to verify. Back to the problem - galvanized anti-rust fastener.
For example, there is no need to be oiled or even bolted, and there is no need to tighten. The chemical composition of the fastener is very important, so in most cases the chemical composition is the acceptance index. The chemical composition also determines whether the mechanical properties and defects of fasteners occur. Less than 0.03%, for example, the amount of magnesium in the grey iron fasteners, gray cast iron casting inevitably will be affected, the occurrence of the chemical composition of bad knot ball is very important, so in most cases, the chemical composition is acceptance. The chemical composition also determines whether the mechanical properties and defects of fasteners occur.
For example, the amount of magnesium in the gray iron fastener is less than 0.03%, and the gray iron casting is bound to be affected, and the failure of the ball is bad. The chemical composition changes with the time of the furnace, and the results of sampling test become the analysis of the furnace condition, and the result is different from the analysis method. Non-ferrous metal fasteners and special performance, high alloy steel fasteners required special cast iron and high temperature alloy fasteners and chemical composition of casting alloy is usually as a technical conditions, for fasteners.
Many are alloy chemical composition does not accept the technical conditions of fasteners, in order to guarantee the quality of fasteners, fastener factory should also in the process of production inspection and control of the chemical composition of the alloy. Construction fasteners, general component is the chemical analysis of furnace inspection and finished product fasteners terminal.
Furnace before trials often adopts thermal analysis method, the fast analysis methods such as ultrasonic, spectrometry, gas rapid analysis method and the corresponding instruments, can quickly determine the content of main component, impurity elements, and in a few minutes of casting alloy liquid or casting alloy dissolved gas analysis in a sample, or all the elements to casting alloy specimen, rapid quantitative analysis.
Taking thermal analysis as an example, the content of carbon, silicon and carbon equivalent in cast iron was determined by the thermal analysis of the continuous cooling curve of the sample, and the inoculation of iron water and the effect of the ball were judged. Through X-ray fluorescence spectrum analysis, we can full analysis of the chemical composition of the sample, the entire process, from the casting sample to print out the results of the analysis, it only takes a few minutes, the use of hydrogen, oxygen and nitrogen gas meter, can quickly analyze the kazakhstan dissolved in the liquid hydrogen, oxygen, nitrogen and other gases.
After the completion of the construction fasteners, chemical analysis method is as follows: titration method, chromatography, decomposition method, volumetric method and gravimetric method, potential method, electric method, point method, colorimetric method, luminescent analysis, photometric method, spectrophotometry, spectral methods, mass spectrometry, chromatography, microprobe analysis, diffraction analysis, thermal analysis and the analysis of gas.