raviswanadha Wrote:hi gordon this is Ravi ,
i have tried spraying tungstun carbide cobolt(metco 71ns) by sulzer metco 9mb gun but i found porosity and the carbide particles were bouncing back. what i need is exact parameters for spraying 71ns.
then do i grind the surface with silicon carbide wheel or diamond wheel. please let me know the procedure as i have lot of work spraying tungsten carbide.
regards
ravi viswanadha
Dear Ravi, you are in a very complicated situation.
First and frankly, plasma praying is not the method for carbides. The jet temperature is too high for optimum coating quality. HVOF/HVAF are the processes to get best coating results. If these methods are not available, then the only solution is to work with (Metco) given parameters.
The bouncing back happens with all materials and spraying methods and is a typical behavior for all materials/processes with bad or normal efficiency factor.
bhe