Martensitic stainless steel wire and additive manufacturing process thereof

The invention discloses a special martensitic stainless steel wire suitable for electric arc additive manufacturing and an additive manufacturing process of the special martensitic stainless steel wire, and belongs to the technical field of additive manufacturing. The wire comprises the following components in percentage by weight: 0.02%-0.05% of C, 0.30%-0.50% of Si, 0.40%-0.70% of Mn, 15.20%-16.00% of Cr, 4.20%-4.70% of Ni, 3.40%-3.90% of Cu, 0.15%-0.30% of Nb, less than or equal to 0.02% of P, less than or equal to 0.01% of S and the balance of Fe and inevitable impurity elements. According to the electric arc additive manufacturing process, a cold metal transition (CMT) + pulse (P) additive mode is adopted, the current ranges from 150 A to 198 A, the voltage ranges from 17.4 V to 19.2 V, the scanning speed ranges from 0.36 m/min to 0.48 m/min, the wire feeding speed ranges from 5.0 m/min to 7.0 m/min, protective gas Ar + 1.5%-2.5% CO2, the gas flow ranges from 15 L/min to 25 L/min, and the interlayer temp