Automatic band steel width detecting method

The invention relates to the field of plate band quality direction, in particular to a band steel width detecting method. The automatic band steel width detecting method comprises the following steps of configuring a detecting device, respectively arranging two groups of x-ray thickness detecting units on two sides of band steel, numbering a plurality of x-way detectors in each group of x-ray thickness detecting units, and respectively moving the x-ray thickness detecting units on the sides towards the central line of a unit from the edge portions of the operation side and the transmission side to perform edge searching operation till three conditions are met at the same time. After the edge searching operation is finished, respective movement distance values of the two groups of x-ray thickness detecting units respectively arranged on the operation side and the transmission side are obtained through displacement sensors, and then a width value of detected band steel is obtained through calculation. By means