Effect of Process Parameters on Microstructure and Properties of Fe-Cr-Mo-B Flux Cored Wire Argon Arc Welding Cladding Layer

The single-pass multi-layer cladding layers were fabricated on the Q235 steel substrate by argon arc welding with Fe-Cr-Mo-B flux cored wire. The effects of cladding current （120, 180, 240 A） and cladding layer number （1, 2, 3） on the morphology, microstructure, hardness and wear resistance of the cladding layer were studied. The results show that the cladding layer had a smooth surface under different process parameters, and there were no defects such as holes and cracks at the interface with the substrate. The cladding layer was composed of Mo₂FeB₂, （Mo, Fe, Cr）₃B₂, α-Fe, M₂₃（C, B）₆ phases. With the increase of cladding current, the number of Mo₂FeB₂ hard phases first increased and then decreased, the size decreased and the shape became regular; the M₂₃（C, B）₆ hard phase changed from continuous network to intermittent network or daisy-shaped; the hardness of the cladding layer first increased and then decreased, and the wear mass loss first decreased and then increased. With the increase of cladding layer number, the number of Mo₂FeB₂ hard phases increased, with the shape changing from block-like to rod-like, and the M₂₃（C, B）₆ changed from intermittent network to continuous network; the hardness of the cladding layer increased, and the wear mass loss decreased.