HVOF coating on bronze bearing housing

[demionkrishan]

Dear team,
Can you please suggest a best possible way to do HVOF coating on bronze base metal?
I have two bronze bearing housing to be coated using HVOF , but so far i haven't experience of doing on bronze base metal. Can you guys help me out??

Regards,
D..K.Francis

[Vadim Verlotski]

Dear team,
Can you please suggest a best possible way to do HVOF coating on bronze base metal?
I have two bronze bearing housing to be coated using HVOF , but so far i haven't experience of doing on bronze base metal. Can you guys help me out??

Regards,
D..K.Francis

Hi Krishan,

HVOF coating of bronzes works without problems, even better than coating of steels. The only thing you should consider is the minimum layer thickness. Since bronzes are much softer than steels, too thin hard coating can be "pushed through" under load. Minimum coating thickness (carbide coating) for bronze substrates will be around 300 microns.

[demionkrishan]

Dear Vadim,
I am not that much good about materials, My concern here is
Bronze melting point is about 1000° C and HVOLF coating flame temperature will
be higher than that so does it work?
2. Which is best for bearing housings - Nickel based alloy powders / Tungsten / Chrome carbide ?
3. if we keep 10 microns per pass will be ok?
4. Do i want to increase the robot surface speed?

Regards,
Krishan

[Vadim Verlotski]

Dear Vadim,
I am not that much good about materials, My concern here is
Bronze melting point is about 1000° C and HVOLF coating flame temperature will
be higher than that so does it work?
2. Which is best for bearing housings - Nickel based alloy powders / Tungsten / Chrome carbide ?
3. if we keep 10 microns per pass will be ok?
4. Do i want to increase the robot surface speed?

Regards,
Krishan

Krishan,

First, the temperature of the substrate has nothing to do with the temperature of the flame. The temperature of the component is usually kept below 150°C during HVOF spraying. It is done using a suitable robot program and efficient cooling. Even with plasma spraying (flame temperature > 10,000°C), the substrate does not get hotter than 150°C.

Second, the best material for plain bearings is your bronze (this part was made of bronze for an important reason!). If you want to repair the original part (reduce the inner diameter), then you should rather use similar bronze powder. If you apply a hard carbide coating instead of a bronze coating, the shaft will wear out instead of a sleeve during operation.

10 micron per pass is quite good for all metallic powders, but 5-7 microns would be better for carbide powders.

Regards
Vadim

[demionkrishan]

Dear Vadim,
Thanks a lot. I have checked with Praxair and they have Cu-114 & 104
hope this will work fine for bearings.

Regards,
Krishan