Fuel for HVOF
05-15-2007, 02:32 PM,
#1
Fuel for HVOF
Hi, forum.
Sorry for my English...
I have one question. Anybody used oxy-fuel systems (e.g. GTV-K2)? What parameters in fuel for HVOF spraying are very important. What fuel can be used on this systems (e.g. Isopar L, exxsol or what)?

How fuel influence on process and coatings quality?

Thank you.
Reply
05-18-2007, 10:43 AM,
#2
RE: Fuel for HVOF
Hi Panf

I would be inclined to only use fuels recommended by the equipment manufacturer or at least proven high quality equivalents with the same combustion characteristics (assuming point is to find cheaper fuel). Combustion properties of the fuel are obviously very important factor, changing these will impact upon coating quality and equipment/process performance.
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05-18-2007, 01:14 PM,
#3
RE: Fuel for HVOF
Hi, Gordon!
Yes, I see. But in principle what products may be fuel for HVOF process? And what is 'Combustion properties'?
how Aromatics Content influence on process and coating quality?

Thank's
Reply
05-18-2007, 04:06 PM,
#4
RE: Fuel for HVOF
Hi Panf

Not sure on the reason for your questions or how best to answer them, but each HVOF system and hardware setup is design around a specific fuel/oxidant combination. Using fuels that are different from those recommended for a particular gun setup is likely to cause problems. A bit like trying to run your petrol engine using diesel fuel or using low octane fuel when you should use high octane fuel. I'm afraid my knowledge of kerosene fuel specifications for use with HVOF is very limited, hopefully somebody with experience can advise you further.
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05-19-2007, 08:47 PM,
#5
RE: Fuel for HVOF
Hi Panf,

for example the recommendation for liquid fuel from PRAXAIR (gun JP-5000) is kerosine JET A1. It?s worldwide used type of kerosine for jet plains.In US it is type 1-K.
These types of kerosene may also cause undue wear on the pump. Kerosene is a very non-lubricous material. To compound this problem, distributors and retailers of kerosene have increasingly begun marketing low sulfur fuels because of various EPA (Environmental Protection Agency) and other government regulations. Low sulfur fuels are even less lubricous than many of the traditional kerosenes.
Moreover, type 1-K kerosene used in the United States is not standardized as regards to lubrication qualities. To compound the matter, 1-K kerosene is generally not available in countries other than the USA. In an effort to select the proper types of fuels, a number of our customers have tried a wide range of kerosene-like products. As a result of their experience and what we have learned, I suggest the following:
1.When selecting a fuel, make every effort to obtain U.S.-supplied 1-K kerosene.
2.If 1-K is not available, select a fuel which has a flash point of approximately 40?C and a boiling point of 280?C. Aviation grades Jet-A and Jet-A1 are often suitable. Jet-A1 has an anti-corrosion additive and is preferred over Jet-A.
3.In no circumstance select a fuel which has flash points approaching 60?C or boiling points over 300?C.
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05-21-2007, 10:17 AM,
#6
RE: Fuel for HVOF
Hi Vladimir

Thank you for your post, very helpful.

Cheers
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05-21-2007, 03:40 PM,
#7
RE: Fuel for HVOF
Hi Vladimir
Thank's for you reply.
Why fuel flash points must be lower 60 grad?
And how Aromatics Content influence on process and coating quality (if you know)?
Reply
05-21-2007, 06:25 PM,
#8
RE: Fuel for HVOF
Hi Panf!

I think lower flash point is better for ignition.
For your second question I havn?t an answer.
Reply
05-21-2007, 07:35 PM,
#9
RE: Fuel for HVOF
Hi Panf

Kerosene (paraffin) as you probably know contain mixtures of hundreds of chemical species in varying amounts depending on the crude oil. refinement and even time of year.

Quote:And how Aromatics Content influence on process and coating quality (if you know)?

Not easy to answer, but my guess would be that a significant change in kerosene composition would effect the combustion properties like; flame temperature/velocity, energy content, stoichiometric combustion ratio with oxygen, flashpoint, boiling point etc.. The effect on HVOF process and coatings assuming no changes to gun hardware and parameters would be just like not setting the parameters properly in the first place. Obviously, the coating quality would suffer, unless gun hardware modifications or parameter adjustments are made to compensate for differences in the fuel.

The only way to really know is the risky business of try it and see Mad0233 sorry getting carried away.
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05-23-2007, 08:45 PM,
#10
RE: Fuel for HVOF
Panf Wrote:Hi Vladimir
Thank's for you reply.
Why fuel flash points must be lower 60 grad?
And how Aromatics Content influence on process and coating quality (if you know)?

Dear Panf,

to your second question: I think, that the aromatic hydrocarbons (anthracen, benzene, benzendiazephin, toluen, naftalen, xylen) content in its molecule the benzene circle. While are burning make carbon black. These can be a cause of worst coating adhesion.
Lower content of aromatic hydrocarbons contents raw oil BRENT, higher contents raw oil from Near East.
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06-21-2007, 09:07 AM,
#11
RE: Fuel for HVOF
Hi to all
We buy Isopar L by EXXON-mobile without aromatic hydrocarbons. But nevertheless we have to much quantity of carbon black in combustion chamber and in coatings.
Reply
07-28-2007, 05:30 PM,
#12
RE: Fuel for HVOF
Hi,

There two types of HVOF Guns.

1.Liquid based 2.Gas based

For liquid based gun generally use kerosine for Job shop applications.Using Robot.

2.Foe Gas based guns use LPG.The gun weight is far less and it can be used in-situ application.

If you require further info you may contact.

Bye

Ravishankar



Panf Wrote:Hi, forum.
Sorry for my English...
I have one question. Anybody used oxy-fuel systems (e.g. GTV-K2)? What parameters in fuel for HVOF spraying are very important. What fuel can be used on this systems (e.g. Isopar L, exxsol or what)?

How fuel influence on process and coatings quality?

Thank you.
Reply
08-03-2007, 03:59 PM,
#13
RE: Fuel for HVOF
Panf Wrote:Hi to all
We buy Isopar L by EXXON-mobile without aromatic hydrocarbons. But nevertheless we have to much quantity of carbon black in combustion chamber and in coatings.

Hello and sorry for my english,

New on the forum!

Most of the time (90%) too much carbon coming from the combustion is related to a harware problem in the gun or on the system and the 10 % left are related to the kerozen.

For kerozen problem juste check the density witch is normaly good (0.8 is a normal value)

Let me know if you are using MK 2 Gun or another one and what is the backpreasure in the gun when the gun is running and if it's not secret Wink
your parameters.

What is the inner diameter of injector and what kind of lightning your system is using : sparkplug or gaz pilot flame.

I will try to help you.

Diucky
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08-03-2007, 04:11 PM,
#14
RE: Fuel for HVOF
Hi Diucky

Sign0016 to the Surface Engineering Forum.

Thanks for your input Big Grin
Reply
12-28-2007, 11:34 PM,
#15
RE: Fuel for HVOF
Vladimir Wrote:Hi Panf!

I think lower flash point is better for ignition.
For your second question I havn?t an answer.

HELLO EVERYBODY
I m surprised to hear that flash point must be under 60 C
for years ,we use kirosen with flash point at 72 C with JP 5000
-distilation interval bigin :198 C END 240 C
-auto inflamation 230 C.
I think we have a good ignition and few oxydation
some years ago we were using the same kirosen with a manuel old jam box and other parameters,it was horrible oxydation . I think the regulation kirosen pressure is importante to reduce oxydation
Reply
02-11-2008, 04:54 PM,
#16
RE: Fuel for HVOF
Hi Panf / All,

I'm not an expert on Kerosene but have experienced that different parts of the world may have different properties within the same grade of Kerosene. For example, Jet A1 in UK may be called Jet A1 in the middle east but will have different additives due to local storage climate etc. (see post from Gordon above re Kerosene differing).

As has been suggested, in some cases, the only thing you can do is try it out. Most manufacturers only have spray parameters as a guideline. It is the quality of flame and coating that is important. Therefore you may need to start off with the manufacturers parameters and then change the fuel/oxygen ratio to acheive the optimum coating with that fuel.

Good luck.
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