Spraying 86-10-4 extra thick
07-05-2019, 02:23 PM,
#1
Spraying 86-10-4 extra thick
Does anyone have experience spraying tungsten carbide 86-10-4 up to .055" thick?
Customer is requiring .050" finished thickness all around on their impeller. I know the risks of cracking and delamination are higher but the customer says that's what they want!

Does anyone have tips and tricks to successfully make this work?
I am spraying HVOF with a JP5000

Thanks
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07-05-2019, 05:37 PM,
#2
RE: Spraying 86-10-4 extra thick
With HVAF, its possible but...
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07-09-2019, 02:22 PM,
#3
RE: Spraying 86-10-4 extra thick
I am using HVOF gun Metco DJ2700. According to metxo datasheet, max thickness is about 0.025”, as sprayed So, far, I have never beeen successful spraying more than 0.03”.
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07-11-2019, 11:18 AM,
#4
RE: Spraying 86-10-4 extra thick
Hello Neufeld!
There are two ways:
1) (Optimal) Try to convince the customer that the thermally sprayed tungsten carbide of 0.008-0.011" thick works better than 0.050". Surfaces of impeller blades experience cavitation wear, so the thicker coating will spall quicker. Of course, erosion and abrasive wear play significant role in reducing of a coating life cycle, but nevertheless... Furthermore, the cost of spraying of 0.05" thick coating will be much higher than for 0.008", but increasing of inspection interval (or overhaul period) is questionable. It seems that the customer took the thickness requirements for WC layer from some specification for plasma arc transferring (PTA) or something else and he isn't familiar with HVOF.
2) (At one's own risk)
2.1) Set up the shortest spray distance - for example, if you usually use 12" try to spray at 6-8"; spray angle should not be less than 75°); traverse speed is 20-27" per second; apply good air cooling to a part, temperature should not be greater than 300-350°F - all these factors build compressive stresses in the coating.
2.2) Oxygen to fuel ratio is 2314 (for example: oxygen 880 l/min, fuel 0.380 l/min); feed rate, particle size, carrier gas flow - up to you, some trials are required.

Good luck!

Kind regards,
Artyom
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07-11-2019, 05:21 PM,
#5
RE: Spraying 86-10-4 extra thick
Good luck. With a DJ2700 system I've gotten close to that and agree with Artyom on temperature controls, as well as experimenting with variables. The "Less is More" Wc approach is excellent as well.

I have had good luck with a slight change in alloy. Will the customer accept a different blend? 85-9-5-1 Wc is basically the same thing with the addition of 1 part Ni. This gives it just a little more ductility.

Slow cooling is critical too.

Good luck
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07-17-2019, 08:47 AM,
#6
RE: Spraying 86-10-4 extra thick
(07-09-2019, 02:22 PM)arlen.nurlan Wrote: I am using HVOF gun Metco DJ2700. According to metxo datasheet, max thickness is about 0.025”, as sprayed So, far, I have never beeen successful spraying more than 0.03”.
hallo pak Arlen , bagaimana kabarnya



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07-17-2019, 09:00 AM,
#7
RE: Spraying 86-10-4 extra thick
(07-17-2019, 08:47 AM)gito Wrote:
(07-09-2019, 02:22 PM)arlen.nurlan Wrote: I am using HVOF gun Metco DJ2700. According to metxo datasheet, max thickness is about 0.025”, as sprayed So, far, I have never beeen successful spraying more than 0.03”.
hallo pak Arlen , bagaimana kabarnya

Hello Pak Gito.
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