Study On Cladding Technology Of Ni-based Alloy Based On Arc Cold-Welding

Arc cold-welding technology has the advantages of high efficiency,high heat concentration,low heat input,small heat affected zone of the substrate.It can greatly improve the surface performance of the workpiece.It is often applied to the fusion cladding and repair welding of carbon steel and cast iron parts.The cold-welding of iron-based alloy is mostly used as the cladding of material,but the cold-welding of Ni-based alloy is rarely reported.Ni-based alloy has low beginning melting temperature,excellent wear resistance and corrosion resistance.Ni-based alloy has also good wettability toward iron-based materials and good metallurgical bonding between Ni-based alloy and iron-based material.Ni-based alloy has become a functional cladding material that is commonly used in industry for wear resistance,corrosion resistance,and high temperature oxidation resistance.The study on cladding technology of Ni-based alloy based on arc cold-welding can expand the application range of Ni-based alloy cladding.In this study,the following innovative works were completed:?1?The arc cold-welded fusion cladding tests find that the Ni-based alloy fusion cladding layer fabricated by arc cold-welding mainly contains?-Ni,Ni₃Si,and CrB phases,and the microstructure of the fusion cladding layer is uniform and fine,and contains an amorphous structure.At the top of the near-fusion cladding layer,the dendrites are slightly finer and unknown directionality,and at the same time,fine feather-like structures are observed between the dendrites.After heated treatment,with the increase of the heat treatment temperature,the dendrites of the fusion cladding gradually decreased and columnar grains and cell crystals gradually increased;Fusion cladding amorphous alloys generated nanocrystalline alloys hard phases in-situ,which made the microstructure of the fusion cladding layer enhanced twice.?2?The metallographic microstructure of the cold-welded fusion cladding layer cross-section shows that there is a clear white bright zone at the interface of the fusion cladding and substrate,forms a good metallurgical bond.In the heat-affected zone,after rapid cooling fine martensites are formed,and the heat-affected zone is small,with a thickness of about 200?m.?3?After the friction and wear tests,the observation of the morphology of the wear scars of the fusion cladding layer shows that the wear mechanism of the Ni-based alloy fusion cladding layer fabricated by arc cold-welding is mainly the adhesive wear and the abrasive grain wear;Compared with the 45#carbon steel substrate,the amount of wear of the Ni-based alloy fusion cladding layer fabricated by arc cold-welding decreased by 77%,and its wear resistance is significantly better than that of the substrate.?4?After proper heat treatments,the cross-section hardness test of the fusion cladding layer shows that its hardness increased,the hardness value could reach745-983HV,and the hardness of the fusion cladding is 2.5-3.5 times that of the substrate.With the increase of heat treatment temperature,the wear amount of Ni-based alloy fusion cladding layer firstly decreased and then increased.When the heat treatment temperature is 525°C,Ni-based alloy fusion cladding layer has the lowest wear and the best wear resistance.Wear scar depth and wear scar width also indicates that the Ni-based alloy fusion cladding layer has the best wear resistance when the heat treatment temperature is 525°C.?5?The corrosion tests shows that the corrosion resistance of the Ni-based alloy fusion cladding layer fabricated by arc cold-welding was significantly better than that of the induction fusion cladding.After 96 hours and 144 hours of corroding,the induction fusion cladding layer shows typical intergranular corrosion,while the fusion cladding layer fabricated by arc cold-welding shows uniform corrosion,a little local intergranular corrosion and pitting corrosion.