Study On The Relationship Of Element Distribution And Metallographic Structure Of Heating Surface Material By Laser Induced Breakdown Spectroscopy

Recently, with the problem of energy pinch, thermal power plant units develop to be high-capacity and high-parameters. Heating surface is facing a bigger challenge due to the high temperature and high pressure and the erosion-corrosion. The macroscopic properties and microstructure of the metal material will transform because of the long-time serving in the harsh environment. Aging and damage brings cracks, which increases the chance of tube burst. To ensure the stable and safe operation of power plants, we should pay more attention to heating material safety.Laser Induced Breakdown Spectroscopy(LIBS) is a new type atomic emission spectroscopy analysis technique with little ablation, which is deemed as a non-destructive testing technology. Comparing to the traditional testing methods, LIBS has lots of advantages, such as rapid detection, nondestructive testing, etc. In this paper, we take advantages of matrix effects of LIBS to analyze the spectral characteristics, as well as the influence of element distribution and relationship with metallographic structure, and distinguish different 12Cr1 MoV samples with the results.First we introduced the background and significance of the paper and summarized the strengths and weaknesses of traditional testing methods. We took a brief introduction of Laser Induced Breakdown Spectroscopy technology and the research status of the world wild.Secondly, we use MicroSpot focusing lens to get smaller laser spot and observed the variation of spectral characteristics. With the analysis of the nonuniformity of surface spectral intensity distribution and the comparison of different elements, we found the element with less content is more nonuniform. Which indicates there is no connection between single-point LIBS spectroscopic data and the sample characteristic.After that we adjusted the experiment bench and parameter, and compared the intensity distribution of different metallographic structure 12Cr1 MoV samples. After the comparison and analysis of average methods, we obtained the reasonable data average method. In order to make the LIBS spectral characteristics can accurately describe the characteristic of heating surface material.Then we compared the spectral characteristics of different metallographic structure12Cr1 MoV samples, including intensities, plasma temperature, electron concentration and intensity ratio. We used the difference to distinguish the different metallographic structure12Cr1 MoV samples. We associated the spectral characteristics with the hardness of the samples to predict the failure of heating surface material.At last, we made a conclusion of the research and summarize the innovative point of this paper and make a suggestion of the further work.