Slag preventive structure for use in welding of automobile dashboard beams

The invention discloses a slag preventive structure for use in welding of automobile dashboard beams. An automobile dashboard beam is placed on a support base and is provided with a standard part; one side of the support base is provided with a pneumatic clamping mechanism; the pneumatic clamping mechanism comprises a mounting base fixed on the support base, a cylinder disposed on the mounting base and a presser head disposed on an output shaft of the cylinder; one side of the upper end of the presser head is provided with an L-shaped block; the L-shaped block comprises a transverse arm and a vertical arm perpendicularly connected to the same; the transverse arm is fixed to the presser head; a protective housing is fixed to the vertical arm; the protective housing houses the standard part. The slag preventive structure can protect the standard part well, welding slag is avoided spattering to a screw thread of the standard part, and the quality and performance of an automobile is guaranteed.