Characterization of carbides in powder high-speed steel based on digital image processing
SHI Hui1.，WU Binhan1.，LU Yuhua2.，YU Xing1.，ZHU Yifei1.，ZHANG Songchuang1.，
WAN Weihao2.
（1. Beijing Key Laboratory of Metal Materials Characterization, NCS Testing Technology Co., Ltd., Beijing
100081, China; 2.Beijing Advanced Innovation Center for Materials Genome Engineering, Central Iron and
Steel Research Institute, Beijing
Abstract：Aiming at the problems of characterization of small, numerous and complicated carbides in powder met‐
allurgy high speed steel, based on the high-throughput field emission scanning electron microscope，a quantitative
characterization method of carbides in powder metallurgy high speed steel was established by means of digital im‐
age processing. By filtering, double threshold segmentation, feature extraction, expansion, corrosion and skeleton
extraction on a large number of SEM images, the method can quickly obtain the quantitative statistical distribution
information of carbides in SEM images. It has been applied to the quantitative analysis of the size, quantity and dis‐
tribution of MC, M6C type carbides of AHPT15M in different states. The results show that the carbide size distribu‐
tion of AHPT15M is 0-5 μm, and the carbide size below 2 μm accounts for more than 95% of the total carbide.
The area fraction of carbide area in annealed speed steel is 21.62%, of which the proportion of MC type carbide is
14.05%, and that of M6C type carbide is 7.57%. After heat treatment, the area fraction of carbide decreases to 15.05%, of which the MC carbide is 10.47%, and that the M6C carbide is 4.58%. The quantitative result of carbides
obtained by this method is consistent with the statistical data of physicochemical phase analysis. It shows that this
method can quickly identify carbides of a large number of images in powder metallurgy high speed steel, and the
results are more comprehensive.
2023, Vol. 33 
