Arc narrow gap welding of the 35L carbon cast steel (cast carbon steel J03502, grade 1) and the 110G13L high-manganese steel (austenitic manganese steel, ASTM A128) is performed using chromium-nickel-manganese wires in a shielding gas mixture (GOST R ISO 14175-2010 - M21). The welded samples are examined by different methods including optical metallography, hardness measurement, and mechanical tests. The weld metal structure along the weld height in the welded samples proves to be fairly uniform, namely austenite with ferrite inclusions. The experiment results show that the mechanical properties of the weld metal correspond to the intermediate values for the joined steels. The developed technology has made it possible to produce a welded joint with high mechanical properties and a ductile structure.