Co-based alloy welding layer deposited by plasma surfacing on Q235 steel was introduced. Dry friction and abrasion behaviors of surfacing layer were examined by block-on-ring friction and abrasion tester. The microstructure and property of the surfacing layer were studied by adopting optical microscope, scanning electron microscope(SEM), X-ray diffractometer(XRD) and microhardness tester. The results show that the surfacing layer microstructure is made up of dendrite(γ-Co) and eutectic structure(γ-Co+M7C3)....