Experimental Study On High Speed Arc Spraying-laser Remelted Composite Prepared Fe-based Coating

FeCrNi, FeCrAl, FeCrNiAl and FeCrNiAlBSi cored wire were manufactured, use stainless steel coated with suitable size and proportion of Fe, Cr, Al, Ni, etc. metal powder, then four kinds of Fe-based coatings were successfully prepared with suitable high speed arc spraying parameters. FeCrNiAlBSi coating were remelted by laser technology, explore the optimal parameters. Comparative study the abrasion resistance, high temperature oxidation resistance, microstructure and properties of the matrix, FeCrNiAlBSi coating and laser remelted layer by microscope, micro hardness tester, scanning electron microscope(SEM) with subsidiary energy dispersive spectrometer(EDS), X-ray diffraction (XRD). The main conclusions of the study are summarized as follows:The cross-sectional structure of the four Fe-based coatings prepared with air pressure 0.5MPa, arc voltage 32-34V, current 200-220A showed a typical layered structure, the microstructure of FeCrNiAlBSi coating structure is densified and low porosity, with a higher microhardness and adhesive strength, microhardness is about 501.0 HVo.i-673.2HVo.i and there is a big unevenness of the microhardness, combined strength is about 17.2MPa. FeCrNiAlBSi coating mainly consist of Fe-Cr phase, metal oxides and a small amount of porosity.Repeated remelting experiments showed that the surface quality of remelted layer is good, microhardness is about 837.4 HVo.i with a good uniformity, under the parameters power 280W, defocus amount-0.5mm, scanning speed 180mm/min, overlapping 70%, and the thickness of laser remelted layer is about 340.0um.Porosity inside the coating significantly was reduced and layered organization was eliminated, mechanical bond between the laminate, between the coating and the substrate converted to the metallurgical combine after laser remelting, the surface flatness of the laser remelted layer is better than the arc spraying coating, coating phase mainly composed of Ni-Cr-Fe, Fe-Cr, etc.High temperature oxidation experiment show that, under the condition of 600 ℃ X 48h, laser remelted layer has the best high temperature oxidation resistance with oxidation weight gain is about 4.96mg/cm2, FeCrNiAlBSi coating followed and oxidation weight gain is about 10.35mg/cm2.Friction and wear tests show that friction coefficient of matrix, FeCrNiAlBSi coating and laser remelted layer successively lowered and stabilized. Laser remelted layer has the best wear resistance, FeCrNiAlBSi coating followed. The wear amount of FeCrNiAlBSi coating is about half of the matrix, and the wear amount of laser remelted layer wear was only 1/3 of the matrix.