We are carrying out Boiler Tube Coating by TAFA ARC SPRAY PROCESS. We have TAFA 8030 ARC SPRAY system. These coatings are currently being done in Running units during ANNUAL shutdown in S.- BENDS & ECONOMISER region.

We would like to know if we can carry out coating on New Boiler tubes and if so how does ARC SPRAY COMPARE TO HVOF as far life expectancy is compared. We are currently using BONDARC75B & TAFA 95MXC wires.

WHAT is the life expectancy of Coated & uncoated Tubes respectively.

Will appreciate if anybody has relevant experience on the matter to give us an opinion.

Thanks

Hi Ehasan

Welcome to the Surface Engineering Forum.

May be a little out of touch with this industry, but back in the 90s the old UK CEGB rated plasma spray 50/50 Ni/Cr coatings (no bond coat). HVOF versions of this coating I think would be superior. Obviously the environment next to the coating will be a critical factor, so there is probably not going to be one ideal coating for all situations. Again, estimating life expectancy will be difficult for the same reasons.

Below is a link to an interesting article. I'm not suggesting it as a recommendation, as I have no experience with the product and don't know how much sales hype is being used. You will find it interesting because it is arc spray applied and has comparisons to 95MXC and 625.

Sorry, these links seem to be dead now.
Links deleted.

Thanks for the reply and the link to the othersite. Problem is every body has tall claims and no proper assessment from 3rd party. In any case it was a good lead.

As a group, we have had lot of expriences on boiler tube coating in India and in Europe in 90'ies.As Gordon has rightly pointed out, type of coating materials to be used depends on interacting?environment. For??high ash Indian coal,use high hardness coat to minimize erosion wheras high sulphur Waste heat boiler tubes need corrosion resistant coatings.European coal requires Ni-Cr.In-situ coating operation is much more difficult than OEM
For boiler tube application details, check with my book on 'Advanced Thermally Assisted Surface Engineering Processes',Kluwer Academic Publishings,MA,USA,2004
Ram