The thickness of coating

[minh_8888]

Dear Gordon,
I have a shaft 425 mm diameter with a crack on the surface. After grinding by portable Grinder machine the crack is channel with dimension: 50 mm Length x 20mm Wide x 20 mm Depth.
Please advise whether I can fulfill a channel 20 mm depth by Thermal Spraying Process! And which process can be applied? Powder Flame or Wire arc or HVOF?

Thanks so much for your support
minh_8888

[sreenuvundela]

Hi,

Filling such type of grooves with thermal spray coatings for such high thicknesses is not at all good idea.

Best option is welding only, if welding is not acceptable because of hardned material, then you may try brazing also as alternative.

IF you want to do by thermal spray process only, then best option is twin wire arc process with SS Coating.

Once again i want to make sure that thermal spray process for this type of work is bad option because of mechanical bonding.

I hope gordon and other friends will support my comments.


Regards,

SREENIVAS

[djewell]

Thermal spray is a coating process. It is not intended for applying lots of material. It also will not impart any strength to your part. Your 20 mm deep crack has significantly weakened your part.

Sreenivas is right. You should weld or braze your part to build up the crack. Then, if you want, you can coat the surface to enhance the properties. I would not even consider twin wire arc or any other process to fill the crack.

[sreenuvundela]

Dear djewell,

Very impressive explanation.

Regards,

SREENIVAS

[Meeker77]

Yes, I agree. TIG weld first, if that doesn't work, Braze the crack. Thermal spray will not work for a crack.

[Dr.Boris A.Eizner]

Dear Gordon,
I have a shaft 425 mm diameter with a crack on the surface. After grinding by portable Grinder machine the crack is channel with dimension: 50 mm Length x 20mm Wide x 20 mm Depth.
Please advise whether I can fulfill a channel 20 mm depth by Thermal Spraying Process! And which process can be applied? Powder Flame or Wire arc or HVOF?

Thanks so much for your support
minh_8888

Dear Minh
Use gas burner.
Look our clip on first page.Use wire of mild steel.