Stellite 6 coating with HVOF/Plasma on Ball Valves.
Firstly i wish all the members of the forum A Happy & Prosperous New Year 2011.
coming to the problem we have been doing stellite 6 coating with HVOF/Plasma on Ball Valves. Initially we did not see any problem in coating and also the pressure testing of balls.
recently we sprayed stellite 6 on 300mm balls and lapped them and did not find any problem. But when the balls we subjected to testing we found a chip of the coating.
could you explain any reasons for the coating to chip off during pressure testing and not during lapping process.
i am attaching a couple of photos for your reference.
regards