Poor flame with Ni-based metallic powder - HVOF process

[Roy]

Hello, everyone.

I would like to hear your kind advice on the check points for solving poor flame of HVOF spray gun.

I operates HVOF gun that uses LPG as fuel.
When I tried to spray Ni-based metallic powder(Colmonoy 63HV, Particle size -63/20 um), it seemed powder feed rate was insufficient.
Please see the inserted photo.
When I checked feed rate, it was good - 45g/min.

I adjusted oxy/fuel ratio to increase flame temperature, but there was no change. After trying WC(-45/+15 um) or Co-based metallic powder(-53/20 um), I found out that only Col 63HV had a poor flame problem. I think that the powder quality is okay.

How could I get the proper flame with this metallic powder?
Please advise me as to the check points or hints for trouble shooting.

Yours truly,

[Vadim Verlotski]

Hi Roy,
Powder JK 576 (Stellite 6, -53+10 microns) has quite a lot of fine fraction (< 20 microns), which be hot in the flame. For this reason, the flame be lighter and powder application be greater than in colmonoy 63HV, without any share of fraction < 20 microns. The powder colmonoy 63HV, Particle size -63/20 is simply too coarse for your HVOF system.

[Roy]

Hi Roy,
Powder JK 576 (Stellite 6, -53+10 microns) has quite a lot of fine fraction (< 20 microns), which be hot in the flame. For this reason, the flame be lighter and powder application be greater than in colmonoy 63HV, without any share of fraction < 20 microns. The powder colmonoy 63HV, Particle size -63/20 is simply too coarse for your HVOF system.

Hi Vadim,

Thank you for your kind advice~