基于近年来发展的X射线面探测器技术 ,提出了一种金属板材晶粒尺寸在线检测方法。在细致分析X射线二维衍射几何关系的基础上 ,通过合理采集衍射数据并对其沿方位角积分 ,统计了衍射峰的数量、每个衍射峰的衍射强度和参加衍射的晶粒数目 ,计算了平均衍射强度 ,建立了X射线平均衍射强度与晶粒尺寸之间的关系。以家电用低碳钢板为例 ,在配备面探测器和三维平移样品台的X射线衍射仪上模拟实际工业生产过程 ,用实时采集的衍射图像计算了X射线平均衍射强度和晶粒尺寸。实验和计算结果表明 ,这种方法简单、快速和准确 ,有希望发展成为家电钢板及其它金属板材在工业生产中的晶粒尺寸在线检测技术 Based on the X-ray surface detector technology developed in recent years, an on-line detection method for grain size of sheet metal is proposed. Based on the detailed analysis of the 2D X-ray diffraction geometry, the diffraction data were collected and integrated along the azimuths. The number of diffraction peaks, the diffraction intensity of each diffraction peak and the number of grains participating in diffraction were calculated. The average diffraction intensity was established and the relationship between the average X-ray diffraction intensity and grain size was established. Taking the low carbon steel plate for home appliances as an example, the actual industrial process was simulated on an X-ray diffractometer equipped with a surface detector and a three-dimensional translation sample table. The average diffraction intensity and the grain size of the X-ray were calculated by using real-time diffraction images. The experimental and calculation results show that this method is simple, rapid and accurate, and it is hoped that this method can be applied to the on-line detection of the grain size of industrial steel sheets and other metal sheets in industrial production