Build up with Powder Flame Spray

[Metallurgy_eng]

Hi evryone ,

I want to ask stng
What is the max limitation of build up coating with Powder flame spray (6PII).

Can we coat on the buildig up lyers with HVOF 100 - 200 micron?

For ex. 1 or 2 mm 316 L or other metal powders with 6P-II and than 100 micron WC Co with HVOF

[wilfred1963]

well from my experience in the past i have only used the 6p for soft coatings like nickle graphite not sure what the velocity of hvof would do to a softer base as we would use a standard 3m torch for base coating with nickle base powders prior to top coating with any thing else might be interesting to see if it works..as far as max limits of build up i have in the past put down up to 150 mils of coating with no issues.

[Gordon]

Quote:What is the max limitation of build up coating with Powder flame spray (6PII).

This would depend very much on the coating material used. Look at some of the Metco powder technical/data sheets, many will indicate a maximum thickness limitation.

Quote:Can we coat on the buildig up lyers with HVOF 100 - 200 micron?

Possibly, but it would certainly not be my first choice of process to use for undercoat. HVOF or arc would be my first consideration.

Quote:For ex. 1 or 2 mm 316 L or other metal powders with 6P-II and than 100 micron WC Co with HVOF

If I was forced to used the 6P-II I would use something like Metco 444, 447, 448, 449 type composite "self-bonding" "one-step" coatings - relatively high bond strength, high integrity coatings with very high thickness limitation.

I would avoid 316 and most austenitic steels due to poor bond (would require bond coat) and relatively low thickness limitation and high residual stress. High chromium steels - martensitic stainless steels on the other hand are low stress and have high thickness capability, but would also require a separate bond coat.

[Metallurgy_eng]

Hi Gordon thanks for your answer.

[joyee]

Well i just used the 6p for coating to aluminum and copper.
Well Gorden perform a nice job over here and i agree with his post.

[shantanu]

Just to add another point...if 316L or any other grade of SS has to be sprayed, the preferred way to spray it to 1 or 2 mm is with ARC after a suitable bond coat of say NiAl. You can easily top this up with 100 microns of HVOF coat
Shantanu

[Metallurgy_eng]

actually we sprayed 100 micron Ni-Al with 6PII and than we applied 2,5 mm metco 42C than grinded this coating, after we did grid blasting this surface again and than top of we sprayed WC-Co with HVOF (300 micron). And the results is very good. Thanks for your help gordon.
Note: We used high spray rate parameters for flame spray system.

Best regards