Automatic welding device for pipe flange

The invention discloses a pipe flange automatic welding device which comprises a pipe flange body and a driving mechanism used for driving the pipe flange body to rotate, the driving mechanism comprises two sets of roller carriers, rolling shafts are installed in the two sets of roller carriers, connecting plates are arranged at the two ends of the rolling shafts correspondingly, and four sets of fixing supports are arranged at the other ends of the connecting plates; the four sets of fixing supports are connected through bolts, the pipe flange body is located in the middle of the four sets of fixing supports, and each fixing support is in threaded connection with a fixing screw facing the pipe flange body. The connecting plate comprises an inner disc and an outer circular ring, four groups of connecting strips which are uniformly distributed are connected between the inner disc and the outer circular ring, a moving block is slidably mounted on each connecting strip, and a hole for a bolt to penetrate through