stellite coating 1

[afarboudi]

Hi
is it possible to use stellite coated trims in Boiler feed water services which include amines and hydrazine ?

 

[metengr]

Yes, it is done on valve seats.

 

[pradipgoswami]

Hi afarboudi,

Stellite is not applied as coating. It applied through hard facing process, which creates metallurgic bond between the substrate (C.S/LAS/SS) and the applied hard facing material(Stellite. Stellite-6 is most popular for power plant related applications.For valves, most popular process is Plasma Transferred Arc Process, where powdered stellite is sprayed on the substrate and melted under the plasma arc.

Coming back to your query, Non Nuclear feed water valves are often hard faced with Stellite, to avoid steam cuts and resultant valve leaks.Stellite has generally good resistance to corrosion attack of amines and hydrazines(depending on temperature and PH level). However you need to verify the results with the manufacturer. Stellite has some restrictions on Nuclear Valves.

You may read though the following presentation to a general feel of this alloy.

Thanks.

http://stellite.com/Portals/0/Micro...ces in Wear Resistant Alloys and Products.pdf

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

 

[EdStainless]

The Nuc restrictions are because these are Co based alloys and you have to consider radiation exposure.

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P.E. Metallurgy, Plymouth Tube

 

[afarboudi]

tanx guys