Detection method of nano-carbide precipitates in microalloyed steel

The nano-carbide precipitates in Ti microalloyed steel are obtained through direct thinning. Extraction replica and nondestructive electrolysis extraction, and different detection methods of nano-carbide precipitates are also compared. In the case of direct thinning, the orientation relationship between the nano-carbide precipitates and the matrix can be identified and used to analyze the formation process of nano-carbide precipitates. Since the M₃C/MCmass fraction is more than 45, the MC-type carbide is more difficult to be observed for the direct thinning as compared in the case of extraction replica and nondestructive electrolysis extraction. In addition, direct thinning and extraction replica are only used to observe nano-carbide precipitates in a plane, while nondestructive electrolysis extraction can be used to observe the nano-carbide precipitates in a cube with a certain size, thus delivering representative and repeatable test results. Furthermore, after obtaining the nano-carbide precipitates by nondestructive electrolysis extraction, the phase composition and the particle size distribution of nano-carbide precipitates can be investigated through chemical phase analysis and X-ray small angle scattering. Therefore, the analysis results of nano-carbide precipitates obtained by nondestructive electrolysis extraction are more comprehensive.