10-27-2008, 07:39 AM,
(This post was last modified: 10-27-2008, 07:43 AM by karunanidhi.)
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karunanidhi
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RE: sealer for sink roll coating
(10-23-2008, 12:55 PM)drramc Wrote: In India,thermal spray coatings of Sink Rolls had more failures than sucess, inspite of using the right material and process.The reasons are too numerous to describe here, but mostly due to lack of knowledge in the basics of thermal spraying and the application.
R.Chattopadhyay
Dear Mr. Chattopadhyay
I agree with your comment, But the technological scenario in india is changing rapidly for the last 3-4 years. Earlier thermal spray workshops are been run by workshop supervisors with their past working knowledge without much educational background. But now Themal spray became a Blistering technology for researchers as well as Mechanical and metallurgical engineers in India.
So, my intention of the above long description is , What is the differentiating thing of us from the rest of the world. I believe that IF our effort is sincere and proceeded with right approach there is no barricade for sucess. India is not at all going to be lag behind in any of the technological innovations. One day we have to do it.
and i appreciate your sincere support for the above effort.
with regards
karunanidhi.
(10-24-2008, 01:53 AM)Stephen Booth Wrote: Considering the working conditions, loose fitting tolerances, heavy loading, temperatures, I would not consider using any thermal spray process for the Sink Rolls. Deloro Stellite of Koblenz makes Bushing for the sink rolls of solid stellite materials, or you could even weld the sink rolls with stellite or similar.
Why take the risk on such a critical application.
Dear Mr. Stephen,
I dont think of coating sink rolls as a risk. Because, sink rolls are being coated for a long years and are using successively in steel industries.
we had proper materials for all the surface charecteristics. and quality also can be maintained as desired.
Could you give some more details of your current process.
regards
karunanidhi
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11-13-2008, 10:14 AM,
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karunanidhi
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RE: sealer for sink roll coating
(10-31-2008, 06:14 PM)rayudugirish Wrote: Hi Karuna,
For sealing you can use basically two techniques :
1 Polymer sealer like loctite or any other high temperature sealer will do.
alternately you can do one more thing
2 Apply a flash coat of NiCrBSi using plasma or HVOF. Results are good with plasma. Because after grinding you will not observe any visible porosity and Si will become SiO2 giving glassy finish. And the fluxing nature of the coating will penetrate into the pores. It works fine.
I believe liquid Zn will not dilute any of the coatings as well resist hot corrosion too.
As for as tolerances are concerned we have produced shafts in +- 2 microns.
Girish
Dear Girish,
Thank you for your reply.
With refence to your reply at point 1. Loctite can never fulfill the requirements of sinks roll working environemnt
2. NiCrBsi may control the porosity but it will also differ with the working environment.
the main problems of the above case is thermal shock & dross pickup, so the coating applied on the roll should withstand for the above two charecteristics as well as satisfying the said requirements like porosity and Co-eff of thermal expansion with the bond coat.
Currently we are working on the above case in our R& D, Results reached almost required values. We will reveal the results very soon.
thanks& regards
karunanidhi
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02-11-2009, 09:40 PM,
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RE: sealer for sink roll coating
There is a nano ceramic coating sealer available to close the pores. The life improvement is 2 to 3 times of unsealed carbide coated rolls.
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02-11-2009, 10:56 PM,
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Gordon
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RE: sealer for sink roll coating
Hi Bala Kailasshankar
to the Surface Engineering Forum.
More information on this product would be welcome.
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02-20-2009, 05:55 AM,
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karunanidhi
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RE: sealer for sink roll coating
(02-11-2009, 09:40 PM)Bala Kailasshankar Wrote: There is a nano ceramic coating sealer available to close the pores. The life improvement is 2 to 3 times of unsealed carbide coated rolls.
Dear Mr. Bala kailasshankar,
may i know the nano material & tests that you have performed on the samples. By which process you have applied the coating.
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05-01-2011, 08:32 AM,
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dadasotare
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RE: sealer for sink roll coating
(02-11-2009, 09:40 PM)Bala Kailasshankar Wrote: There is a nano ceramic coating sealer available to close the pores. The life improvement is 2 to 3 times of unsealed carbide coated rolls.
Dear Mr. Bala,
How to be apply this nano ceramic coating saler. Wether it bymanually or by .........Pl. describe.
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