Spraying on nitriding surface

[Panf]

Hi forum,

I need help. We have troubles with HVOF spraying on nitriding surfaces. We use stainless steel FeCrNiBSiC. If coating contact with nitriding surface, his crashed. What I can to do?
May be anybody recommend other material with microhardness around 800HV for repair and build-up.

Thank you.

[Gordon]

Hi Panf

Coating nitrided surfaces can be difficult. It is difficult to get a decent grit blast profile and many coatings appear not to bond too well compared to untreated steel, particularly if white layers are present.

I would recommend removing the nitrided layer if that is possible.

[drramc]

Hi,
Nitrided layer removal, as suggested by Gordon is necessary to build up spray deposit.To soften the nitriding layer you can do a heat treatment at 500-540C,nitriding temperature.Alternatively you can use diamond/or BN tools to remove the thin nitride layer.
ram chattopadhyay

[Panf]

Yes, I see
But what to do, if I coating the surface right against the nitrided surface
I need to place masking shield over nitrided surface, and during spraying the coating deposit on her and crashed

[Gordon]

Hi Panf

Sorry, I am having trouble understanding what you are trying to achieve. Could you try to give us more information (a sketch or drawing may be helpful).

[Panf]

yes, my English is very bad

sorry

I hope Gordon will attach the sketch to my post

[Gordon]

Hi Panf

You can email me here or here with your image ideally in jpg or gif format. Or you could use one of many free file hosting sites, see http://www.gordonengland.co.uk/sef/image...t-139.html