Spray & Fuse coating for Boiler tubes

[Jaydev]

Usually Carbide coating with HVOF & Cored wire coating with Arc spray are well known & adopted processes for Boiler tubes coating in coal based thermal power plant.

I have came to know that spray & fuse coating is also another option for this application!
What kind of boiler tubes are these?
Are these different from the one which is done with either hvof or arc spray?

Kindly share your thoughts, as we are Indian based thermal spray coating manufacturer & based on the new developments & applications worldwide we try to make it better with our resources & spread in the national market.

[Gordon]

Hi jaydev choudhary

I'm sure some fused self-fluxing alloys would work well in some arduous conditions. Its just the hot process side of fusing the coatings that maybe a problem.

[Vig]

Hi Jaydev

Spray and fuse coatings are being used for superheater tubes. Fuse is not a problem if well organised

BR
Vitaly

[abhay]

hi,

This is Abhay, we are providing spray and fuse coatings to glass mould plungers in INDIA,

i want to know about coating boiler tubes by spray and fuse process.

1)what will be the hardness of spray and fuse coating on boiler tubes?
2)what will be the other alloying elements with nicrbsi for this application?
3)if the hardness of the spray and fuse coating is 50 hrc, what kind of post coating treatment is required(considering the size of these tubes)?

50 hrc coatings crack, on atmospheric cooling due to thermal stress(i think it is thermal stress)

[Vadim Verlotski]

hi,

This is Abhay, we are providing spray and fuse coatings to glass mould plungers in INDIA,

i want to know about coating boiler tubes by spray and fuse process.

1)what will be the hardness of spray and fuse coating on boiler tubes?
2)what will be the other alloying elements with nicrbsi for this application?
3)if the hardness of the spray and fuse coating is 50 hrc, what kind of post coating treatment is required(considering the size of these tubes)?

50 hrc coatings crack, on atmospheric cooling due to thermal stress(i think it is thermal stress)

Hi Abhay,

The coating for boiler plants (pipe walls and superheater tubes) has a single goal - corrosion protection. Unlike molds for glass pressing, the wear resistance and the amount of hardness is not necessary. For this reason, pure NiCrBSi alloys are used without carbon and carbides for boiler plants mainly. NiCrBSi layers are relatively soft and do not tend to cracking. Such layers are melted after the flame spraying at about 1050°C. There is no further heat treatment is necessary.

Regards

[abhay]

THANK YOU , VADIM.

so i guess 40 hrc nicrbsi coating will be ideal for boiler tubes.

if corrosion is the only concern, can we give it a zinc (wire flame spray) coating(which is used for structural rust prevention)

it will reduce the cost i believe.

[Vadim Verlotski]

THANK YOU , VADIM.

so i guess 40 hrc nicrbsi coating will be ideal for boiler tubes.

if corrosion is the only concern, can we give it a zinc (wire flame spray) coating(which is used for structural rust prevention)

it will reduce the cost i believe.

Hi Abhay,

Corrosion of boiler components is not the normal corrosion in water, zinc can not help in this case. The tube walls and superheater tubes may be hot up to 600°C. This corrosion is thus a high-temperature corrosion. The most corrosive agents are Chloride and HCl, they attack quickly the iron. Nickel-based alloys (NiCrBSi, Nimonic, Inconel and others) are more stable than iron against such corrosion, but not absolutely resistant.
A detailed information about boiler corrosion you can get here:

https://www.chemin.de/Publikationen/Publikationen.php

Regards

[abhay]

Thank you
Vadim

[SENTESBIR-POWDERS]

[quote='abhay' pid='9748' dateline='1434896272']
hi,

This is Abhay, we are providing spray and fuse coatings to glass mould plungers in INDIA,

i want to know about coating boiler tubes by spray and fuse process.

1)what will be the hardness of spray and fuse coating on boiler tubes?
2)what will be the other alloying elements with nicrbsi for this application?
3)if the hardness of the spray and fuse coating is 50 hrc, what kind of post coating treatment is required(considering the size of these tubes)?

50 hrc coatings crack, on atmospheric cooling due to thermal stress(i think it is thermal stress)


Hi,
My customer ask for Spray and Fuse process and preticularly Castolin RW 12112 powder which is Ni-WC blend.
So we will offer him Sentesbir Ni-WC blend powder with 60 HRC Ni matrix and FTC.
Regards,
Gökhan