Welded steel plate stress detection device

The utility model belongs to the technical field of steel plate stress detection, and particularly relates to a welded steel plate stress detection device, which solves the problems of troublesome fixation and difficult movement in the prior art, and comprises a base and a steel plate, a protective cover is fixedly connected to the top of the base through a screw, a cavity is formed in the protective cover, an air cylinder seat is fixedly connected to the top of the protective cover through a screw, a first air cylinder is installed in the air cylinder seat, and through arrangement of structures such as a first sliding block and a second sliding block, the first air cylinder drives a connecting rod; the connecting rod drives the first sliding block to move upwards, and the second sliding block is partially connected into the first sliding block in a sliding mode, so that the second sliding block can move towards the middle along with upward movement of the first sliding block and is matched with the third pre