Super DSS repair using monel metal spray

[MadieKerang]

Dear all, i would to get an advise. Have anybody experience super DSS shaft repair using monel metal spray on damaged area od shaft. The shaft will be used for seawater pump. Unfortunately, there is no super DSS material for metal spray. Appreciate any feedback.

 

[EdStainless]

I presume that you doing this because of localized wear?
Wouldn't something stronger than Monel be better?
Maybe a Ni alloy like 625?
I have used 625 for local repair on Monel shafts.
We deposited it with HVOF, minimal heat input and maximum density.
If there is any porosity in your coating you are likely to get serious localized crevice corrosion.

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P.E. Metallurgy, Plymouth Tube

 

[Tmoose]

Is the repair on a bearing seat, a seal surface, pump inmpellar mounting seat, or ???

 

[MadieKerang]

Hi Sir, it is on the shaft itself.

Thanks EdStainless, i will have a look into using HVOF using 625, i believe that is the best option we have at the moment.

 

Whatever you do with spray, it is not repair.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Dhurjati Sen]

Dear MadieKerang,

Metal spraying is a very modern and fantastic technique. I know of a gas plant in the middle east where this was done inside stabilization columns.

The coating lasted for only a year.

Regards.

DHURJATI SEN
Kolkata, India

 

[TugboatEng]

Whatever you do with spray, it is not repair.

Why do you feel this way? We metal spray our propeller shaft seal liners when they're new. It works great.

 

[Corroneer]

@Dhurjati Sen … can you elaborate more on your experience with that metal spaying? Service, Ops Parameters, metal used, substrate ... Thanks.

 

[Dhurjati Sen]

Dear Corroneer,

Service - Amine Regenerator Column, bottom dish end

Material - Carbon Steel

Nature of corrosion - Pitting & general corrosion

Metal sprayed - Hastalloy

Regards.

DHURJATI SEN
Kolkata, India

 

[Corroneer]

Thanks for that @Dhurjati Sen, but that seems to me wrong application of the thermal spray rather than unsuitability of the Hastelloy for the service?

 

[Dhurjati Sen]

Dear Corroneer,

Actually I am old school. I would have gone for weld build up and subsequent localized PWHT for the time being and plan for partial replacement at the next turn-around.

I may be biased against these modern repair techniques and inspection strategies, so my opinion should not count.

Regards.

DHURJATI SEN
Kolkata, India

 

[Corroneer]

@Dhurjati Sen, do not say that man ... everybody's opinion is valuable.

Regards.

 

[MadieKerang]

Tqvm all..fully appreciate all your advise