Study On Spectral Characteristics During Laser Cladding

Laser-Induced Breakdown Spectroscopy(LIBS)is a material analysis technique that uses a lens converging pulse laser to excite a sample to generate plasma and analyze its emission spectrum for qualitative and quantitative analysis.In this paper,the laser-induced breakdown spectroscopy method developed in recent years is used to study the defects and plasma spectral characteristics of the cladding layer.Using laser cladding and laser-induced breakdown spectroscopy,the defects on the surface of the large-area cladding layer were studied and graded.The thesis selects cladding samples of different proportions as the experimental samples,and uses LIBS technology to scan the cladding samples over a large area.Through the analysis of experimental data,qualitatively and semi-quantitatively discuss the surface defects of the sample and classify the sample's defect level,and analyze the spectral characteristics of the cladding layer.It provides an effective detection method for large area,fast and efficient cladding layer defect detection and classification.The main content and conclusions of the paper include the following aspects:First of all,the traditional detection of cladding layer morphology and performance is studied.According to the industrial laser cladding technology requirements,the design of laser cladding test schemes,preparation of TiC / Ni35 cladding samples with different contents,laser cladding samples and pretreatment of subsequent samples include sample cutting,grinding and polishing.And use traditional detection methods to detect the performance and defects of the cladding layer.The results show that the cladding layer forms a good metallurgical bond with the metal matrix,and the cladding layer is densely organized;the overall forming quality of the cladding layer is ranked from good to poor: 100%Ni35 ?94%Ni35/6%TiC?97%Ni35/3%TiC?91%Ni35/9%TiC?88%Ni35/12%TiC.Secondly,research on LIBS detection and classification of cladding surface defects.Aiming at the requirement of defect analysis of cladding layer,LIBS detection method is proposed.The results show that it is feasible to use LIBS technology to detect and classify defects in large-area cladding layers;to classify cladding layer defects according to more than two elements can reduce experimental errors;LIBS line scan results are more sensitive and sensitive to micro areas The identification is more obvious.Final grading result: 88% ni35 / 12% TIC cladding samples have the most defects.Defects of 91% ni35 / 9% TIC cladding samples ranked second.94% ni35 / 6% TIC cladding samples have the least defects.The defects of 100% ni35 cladding samples and 97% ni35 / 3% TIC cladding samples are similar between 94% ni35 / 6% TIC cladding samples and 91% ni35 / 9% TIC cladding samples.Finally,research on the plasma characteristics of the cladding layer.In view of the hardness properties of the cladding layer,laser-induced breakdown spectroscopywas used to study the correlation between the hardness and spectrum of different scanning cladding samples.Collect the spectral data of samples with different hardness to extract the spectral intensity ratio of ion and atomic spectral lines and compare with the micro hardness of the sample.The results show that the plasma line intensity,ion line atomic line intensity ratio,and plasma temperature cannot establish a direct linear relationship with hardness.There is a large systematic error in hardness testing,which makes it impossible to establish a correlation between hardness and spectrum.