变截面铸钢件是高速列车常见零部件，应用X射线照相法检测难度很大。采用450 kV X射线数字平板成像检测系统(DR)，采用光栏限束准直器、叠加曝光或连续透射以降低图像噪声；屏蔽散射线以提高信噪比；利用软件调节以增强图像细节，达到充分利用数字成像动态范围大、宽容度良好的特性，成功地检测了高速列车变截面铸钢件中的各种缺陷。

The variable cross-section cast steel parts are common parts in high-speed trains, and it is very difficult to apply X-ray radiographic inspection to it. But fortunately, the X-ray DR system could acquire richer original image; the continuous exposure Log-calculation or the images averaging could decrease the noise; the scattered radiation shield could improve the signal to noise ratio; the logarithmic demodulation could enhance the image details; and the digital radiography could get wide dynamic range, and have excellent Latitude. By using all these methods and technologies, we successfully tested various defects of the cross-section steel castings in the high-speed train.