Surface hardening techniques of steel are of important practical significance for the production of wear-resistant parts. Hardfacing is a well-recognized technique that is efficient and economical. In this work, a martensitic stainless steel hardfacing coating was deposited by multiple-pass MIG welding. The surface wear and corrosion resistance of the Q345 steel were significantly improved by the coating. The bonding strength between the substrate and the coating is greater than the tensile strength of the substrate. The microstructure of the coating consists of lath martensite embedded with (Cr, Fe) 7C 3 particles. The formation of martensite in the coating plays a vital role in improving the wear resistance and bonding strength. The presence of a large amount of chromium imparts excellent corrosion resistance to the coating. The wear resistance increases while the corrosion resistance decreases in the order of X12Cr13, X20Cr13, and X30Cr13 coatings. X30Cr13 coating has the best wear resistance among these three coatings. Hence, the optimum coating is X30Cr13 coating. These results highlight new possibilities for the surface hardening of steel.