Application of MATLAB Software in Quantitative Analysis ofStructure of Railway Wheel Steel

Firstly, the traditional quantitative metallographic method was used to calculate the proportion of proeutectoid ferrite in two new railway wheel steel. Secondly, the grey treatment for the SEM image of the wheel steel structure was carried out by using MATLAB software. It was observed that the grayscale histogram was a single peak distribution. Afterwards an improved triangle algorithm for segmentation of SEM image of wheel steel structure was proposed based on the characteristics of gray histogram. The main idea of the algorithm is as follows: a line segment could be acquired by connecting the maximum value of the wave crest and the minimum value on the left side of the gray histogram waveform, then a vertical line to the acquired line segment would be made and the intersection distance to the waveform should be the longest. Furthermore, the ultimate intersection point between the vertical line and the histogram waveform would be selected as the image segmentation threshold. Compared with the results of traditional quantitative metallographic analysis method, this method had better accuracy and higher calculation efficiency, which can provide reference for calculating the proportion of proeutectoid ferrite phase and pearlite phase in railway wheel steel.