Study Of The Efficiency Of Electric Spark Cladding

In order to improve the cladding efficiency of the electric spark deposition, theeffects of the electrode materials and cladding process parameters on the claddingefficiency were studied. The cladding process parameters include electric capacity,discharge frequency, electrode rotation speed and cladding time. Before the orthogonalexperiment, the process experiment of individual process parameter was carried out.Then the process optimization experiment was done by orthogonal experiment basedon the individual process experiments. The alternating cladding methods were alsostudied to further incease the cladding efficiency. They are the high and low energyalternating cladding and the different electrode materials alternating cladding.The characterization of microstructure and composition of the cladding coatingwere analyzed by the mean of the optical microscope (OM), X-ray diffraction (XRD),scanning electron microscope (SEM) and Electron energy spectrum (EDS). Thecharacterization of the cladding coating includes surface morphology, micerostructure,alloy distribution and so on. The main conclusions were as follow:The physical and chemical properties of the electrode material could affect theESD efficiency. The melting point of electrode material is higher, the claddingefficiency is lower. The cladding efficiency would increase with the increase of theelectric capacity, discharge frequency, electrode rotation speed and cladding time.However, cladding efficiency would fall sharply if the cladding time was more than acertain time.The surface morphology of electric spark cladding coating is a splash shape. XRDanalysis results indicated that Ni base cladding coating of ESD is composed of the richNi solid solution, CrSi2, FeNi3, Cr2B and so on. Electronic energy spectrum analysisresults show that Fe, Ni, Cr, Mn alloy elements in the coating and base metal canmutual diffusion to form a kind of metallurgical bonding between the cladding coating and substrate.Although the alternating cladding methods, both high and low energy claddingmethod and different electrode materials cladding method, can improve the claddingefficiency, the later process route should be better.The optimizational process parameters of the high efficiency ESD were as follow:electric capacity120μF, discharge frequency100Hz, electrode rotation speed293r/min,cladding time10min. Among these process parameters, the electrode rotation speed isthe key factor that affected the cladding efficiency.