Preparation And Research Of Cavitation Performance Of The Cladding Layer Of Cobalt Alloy On The Stainless Steel

In modern industry,316stainless steel has been used under many harsh conditionsbecause of its own excellent mechanical properties and high temperature strength such asocean Equipment, chemical dyes, agricultural fertilizers and other production equipment;photography, food industry, machinery parts and so on. However, due to its poor resistanceto atmospheric corrosion and wear, thereby they affect the service life of its own. With thedevelopment of high energy and maintenance welding spark deposition technology, theyprovides an effective approach for316stainless steel surface hardening coating preparation,repair and remanufacturing.In this paper, Micro-arc spark deposition and high welding with Stellite alloy as thecoating material on316stainless steel substrates was carried out. The microstructure,chemical compositions, phase identification and hardness of the deposition layers wereexamined by using scanning electron microscopy (SEM), energy dispersive X-rayspectroscopy (EDS), X-ray diffraction (XRD) and micro-hardness tester, respectively.Moreover, through experiments of wear resistance and cavitation erosion, the corrosion andwear resistance of the samples were analyze were analyzed systematically.The results show that the morphology of the single pulse deposit is splash-shape. Alarge number of the single pulse deposits were superimposed continuously and thendeposition layers with a certain thickness were formed. The epitaxial growth coating withcolumnar grains was then achieved by micro-arc spark deposition. The coating of Stellitealloy has a good metallurgical combination with the316stainless steel substrate. Thecoating layer is mainly composed of γ-Co solid solution, Cr carbide and Co6W6C phases.With the deposition of micro-arc voltage increases, the microstructure of deposited layer isslightly coarse and the hardness has a decreasing trend, then the average hardness of thedeposited layer over the316stainless steel substrate increased by about2.5times. Thedeposited layer of Welding energy is mainly composed of γ-Co and M23C6other phases.The Cladding microstructure appears roughly dendrite growth, and the dendrite growthdirection remains almost the same. There is no obvious characteristic structure at thecross-section of the "white band" transition layer and there is a good metallurgical bond between the cladding layer and the substrate. The cladding layer hardness is superior to316stainless steel which increased by2times. Under two enhanced methods, the wearperformance of Stellite alloy was significantly higher than the substrate, and the main wearmechanism were adhesive wear, oxidation wear and abrasive wear. With the normal loadincreases, the friction coefficient decreases. The cavitation performance of Stellite coatingis significantly better than the substrate and the lose weight was only the1/5of thesubstrate under the same time. After cavitation, the hardness of Stellite alloy increasedwhich in turn improve its own anti-cavitation performance.