Low-temperature steel splicing welding trolley and welding method

According to the low-temperature steel splicing welding trolley and the welding method, an argon filling box is a square box with the top open, a plurality of square grooves are symmetrically formed in the two sides of the argon filling box, the height of the square grooves is the same as that of the argon filling box, T-shaped bolts sequentially penetrate through top plates and pressing plates of the square grooves, and plates to be welded are located between the top plates and the pressing plates of the square grooves; a welding seam formed by the two to-be-welded plates is located above the argon filling box, a welding gun is arranged above the to-be-welded plates, and the welding gun is fixed to the welding gun trolley through a welding gun support. The argon filling box is located in the argon filling box bracket, the argon filling box bracket is provided with a front support and a rear support, the front support and the rear support are each fixedly provided with a set of pulley blocks, the pulley block