The invention discloses a
dissimilar metal welding method of low-
carbon steel and
cast iron. The method comprises the following steps of S1, preparing of
base metal, wherein the carbon content of the low-
carbon steel is smaller than or equal to 0.6wt%, the thickness of the low-
carbon steel ranges from 0.5 mm to 8 mm, the carbon content of the
cast iron ranges from 2wt% to 4wt%, and the thickness of the
cast iron is larger than or equal to 1 mm; S2,
base metal surface cleaning and assembling, wherein the
base metal is cleaned,
oxide and oil
dirt on the surface are removed, the to-be-welded low-carbon steel and cast iron subjected to
surface cleaning are in
lap joint and are assembled, a tool clamp is adopted for fixing, a to-be-welded part is formed, and the
assembly gap of a
lap joint of the low-carbon steel and the cast iron is smaller than or equal to 0.5 mm; and S3, a
welding process, wherein a
galvanometer laser welding head is adopted, swinging and self-fluxing welding are carried out in the
welding process, the low-carbon steel is all subjected to penetration through
laser welding, the side surface of the cast iron is partially molten, and the contact faces of the low-carbon steel and the cast iron are subjected to self-fluxing to form a
weld bead for fixed connection. According to the method, the welding cost can be reduced, and the anti-
cracking performance of the
weld bead can be improved; and compared with traditional welding methods such as gas shielding welding, deformation of the
welding joint is small, and the obvious technical advantages are achieved.