Influence of welding current on microstructure and properties of nickel-based alloy hardfacing by plasma transferred arc welding

In order to improve the abrasion resistance of Z2CN18-10 stainless steel, the nickel-based alloy powder was deposited on the Z2CN18-10 stainless steel by plasma transferred arc welding. The microstructures, phase structure, compositions, microhardness and wear resistance properties of the hardfacing layer with different welding currents were characterized by scanning electron microscope, energy disperse spectroscopy, X-ray diffractometer, microhardness tester and abrasion tester. The results show that the surfacing layer mainly consists of γ-Ni and precipitates such as FeNi3, Cr23C6, Cr7C3 and CrB. The microstructures of nickel base alloy surfacing layer vary from clusters of petals to aquatic plants and the banded structure with the increase of welding current. At the welding current of 110 A, the hardfacing layer possesses the highest average microhardness of 898 HV, and its wear resistance is the best, and its relative wear resistance is 13.76, compared with the substrate. Wear mechanism of the hardfacing layer is adhesive and abrasive wear early, and then oxidative wear later.