The invention relates to the technical field of steel plate sampling detection, and discloses a fixed-length
cutting device for hot rolling production of a medium-thickness plate, which comprises a shell, the interior of the shell is hollow, a guide
assembly, a positioning roller and a transmission roller are respectively arranged at the front part, the middle part and the rear part of the interior of the shell, and the guide
assembly, the positioning roller and the transmission roller are all located at the center line of the interior of the shell; the number of the positioning rollers is two, the number of the transmission rollers is two, a dividing
assembly is arranged between the positioning rollers and the transmission rollers, the dividing assembly comprises a truss, a plurality of
water jet cutter heads are arranged on the truss, and the
water jet cutter heads are used for conducting
cutting and sample separation on a plate, utilizing
cutting liquid of a
water jet cutter and guiding the cutting liquid into rotating guide rollers. The guide roller is cooled, so that when the guide roller guides a high-temperature plate, the
cooling effect on the high-temperature plate is achieved, and the situation that due to the fact that the temperature of the plate is too high, water jet liquid is gasified and even subjected to
steam explosion when the water jet works is avoided.