COBEM99

S18 Processos Mecânico-Metalúrgicos

Title:

MULTILAYER LASER CLADDING

Summary :

ABSTRACT. LASER CLADDING TECHNIQUE CONSISTS ON OBTAINING AN HOMOGENEOUS SURFACE LAYER WITH A STRONG METALLURGICAL BOND, A LOW DEGREE OF DILUTION AND MINIMAL DISTORTION. THE PROCESS USUALLY INVOLVES THE DELIVERY OF FINE GRAINED POWDERS DIRECTLY INTO THE MELT POOL DURING LASER IRRADIATION. MUCH HAS BEEN DONE REGARDING THE FEATURES OF THE COATINGS PRODUCED, AS A RESULT OF PROCESSING PARAMETERS FOR DIFFERENT MATERIALS. ALTHOUGH LASER CLADDING PROCESSING HAS SHOWN SEVERAL ADVANTAGES OVER COMPETING TECHNIQUES, SUCH AS WELDING OR PLASMA COATING, THE VAST MAJORITY OF LASER CLADDING RESEARCH HAS BEEN CARRIED OUT ON ONE LAYER CLADDED SPECIMEN. THIS CAN BE AN IMPORTANT LIMITATION TO THE PROCESS, PARTICULARLY WHEN RECOVERING OPERATIONS ARE CONCERN. DURING MAINTENANCE OPERATIONS, MOST FREQUENTLY MATERIAL HAS TO BE ADDED TO FILL UP IRREGULAR SURFACE AREAS THAT HAVE SUFFERED SOME SORT OF DAMAGE SUCH AS EROSION. IN ORDER TO BE ABLE TO ANSWER TO THIS REQUIREMENT, IT IS VERY IMPORTANT TO KNOW THE EFFECT OF OVERLAPPING SUCCESSIVE LAYERS BY LASER CLADDING TECHNIQUE. THIS WORK, SHOWS THE EFFECT OF DEPOSITING MULTILAYERS OF A COBALT BASED ALLOY, STELLITE 6, ON THE FEATURES OF THE COATED SURFACE. SPECIMEN WITH DIFFERENT NUMBER OF SUCCESSIVE LAYER WERE PRODUCED WITH A CO2 CW LASER. THE INFLUENCE OF MULTILAYER CLADDING ON MICROSTRUCTURE AND MECHANICAL CHARACTERISTICS WAS STUDY. RESULTS ARE DISCUSSED BEARING IN MIND THE POTENTIAL OF LASER CLADDING AS A TOOL FOR REPAIRING OPERATIONS. KEYWORDS: LASER CLADDING, HARDFACING, COATINGS, SURFACE TREATMENTS

Author :

DOliveira, Ana Sofia C.M.
Shigemori, A. 0
Villar, R. 0

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