The invention relates to a
welding method of a girth weld of an inner cladding thin-walled stainless steel composite tube. The
welding method comprises the following steps: girth welds of the inner cladding stainless steel composite tube are respectively and gradually welded by three
welding seams, an inner cladding layer welding seam and a
transition layer welding seam are welded by
argon tungsten-
arc welding, the stainless steel inner cladding layer welding seam adopts welding wires with the same quality thereof, the
transition layer welding seam adopts ER309 welding wires, and the base layer is welded by
shielded metal arc welding or CO2 gas shielded welding and adopts a welding material matched with the strength of the base layer; and the inner cladding layer, the
transition layer and the first layer of the base layer are welded under back
argon gas protection. The welding method guarantees
corrosion resistance of a joint of the inner cladding layer and
mechanical property of a
welding joint of the base layer; and the method plays an important role in promoting wide application of the inner cladding stainless steel composite tube in businesses such as oil-gas delivery,
chemical industry, oil refining and the like, improving
corrosion resistance of an inner wall of a
pipe, and solving the problems of high cost and the like caused by adopting a full wall-thickness stainless steel
pipe.