Abstract: The present disclosure discloses a welding gas shielding device, a laser filler wire welding system and a welding method. The welding gas shielding device comprises an upper shielding gas dragging cover device and a back shielding gas device. The laser filler wire welding system comprises a welding gas shielding device, a height adjusting mechanism, a wire feeding system, a laser system, a numerical control console and the like. The welding gas shielding device for narrow gaps made of dissimilar materials is reasonable in structural design, gas shielding can be carried out on the upper area and the lower area of a welding area in the welding process of the narrow gaps made of dissimilar materials, the problem that laser narrow-gap welding gas shielding is insufficient and unstable is solved, the weld joint cooling speed can be adjusted and controlled, the shielding effect is enhanced, and the welding efficiency is improved.

Abstract: The disclosure provides a low-nickel nitrogen-containing austenitic stainless steel flux-cored wire and a preparation method thereof, and belongs to the technical field of welding materials. The disclosure aims at solving the technical problems of nitrogen element loss, air holes, hot cracks in a welding seam area, and pitting corrosion caused by nitride precipitation in a heat affected area that are easily generated in a welding joint when low-nickel nitrogen-containing austenitic stainless steel is welded in the prior art. The flux-cored wire of the disclosure is prepared from a flux core and a stainless steel sheath. During welding, gas protection is not needed. The flux core is formed by mixing an alloy component and a slag system. The alloy component is formed by mixing electrolytic manganese, ferrosilicon, chromium metal, nickel metal, ferromolybdenum, copper powder and ferrochrome nitride powder in percentage by mass.