Re: 410 SS HVOF Application

Posted by Gordon England ( on 15:57:38 07/02/05

In Reply to:410 SS HVOF Application posted by john winne

typical 316 type stainless steel HVOF coating microstructure

: Currently experiencing unmelts/deformed particles when spraying -325 410SS through JP5000. Best results (deformed particles) have been with Oxy 167, Fuel 130, Comb Press @ 120 psig, although oxide stringers are beginning to appear. Nozzle length is 4" Suggestions have been to increase nozzle length to 6". Stand-off is 15.5" Have tried mfr parameters -125 Oxy,110 Fuel, Comb 95, but coating erodes itself while spraying and is blue in color indicating that it has completely oxidized. Hardness is 35 Rc. Powder flow is 10 LBs/Hr.

Hi John

It is difficult to comment without seeing the coating metallography. Unmelted particles in HVOF coatings are not necessarily a bad thing (see example) and are typically quite high in many HVOF coatings. As long as the coating density is high they should not be a problem. Adjusting parameters to completely remove them usually results in higher oxide content. The blue colour may be indicating over heating of the coating.

Regards Gordon

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