Protective device for lower cross beam of titanium plate hot rolling production line

A titanium plate hot rolling production line lower cross beam protection device comprises a lower cross beam and guide wheel mechanisms, a plurality of guide wheel mechanisms are arranged on the inner side of the lower cross beam, each guide wheel mechanism comprises a rolling shaft, a positioning ring, threaded sleeves, threads and a guide wheel set, the guide wheel sets are arranged at one ends of the rolling shafts, the threads are arranged at the other ends of the rolling shafts, the threaded sleeves are arranged on the outer sides of the threads, and the positioning rings are arranged on one sides of the threaded sleeves. The positioning ring is sleeved with the rolling shaft; when a titanium plate is rolled, the rolling shaft is arranged on the lower cross beam in a penetrating mode, the positioning ring is placed, the threaded sleeve is screwed on the threads, the rolling shaft is fixed by extruding the positioning ring, when the titanium plate passes through the lower cross beam, the guide wheel set r