06-21-2011, 12:41 PM,
(This post was last modified: 06-21-2011, 02:57 PM by Justin.)
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Justin
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What is the main factor for affecting the efficiency of melting the powder?
Hello...everyone!
I'm a newbie.
I have a question about melting the powder. I heard a special view point from someone. He said "The powder would be melted better if the gun have higher energy density, although the power of this gun is smaller than the other gun." Is it possible?
I feel confused very much. The energy desity becomes higher and higher with increasing the power, doesn't it?
Please share your experience and opinion.
Thanks.
Justin
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06-21-2011, 03:19 PM,
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Justin
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RE: What is the main factor for affecting the efficiency of melting the powder?
(06-21-2011, 02:47 PM)Metallurgy_eng Wrote: What types of gun ? and what types of fuel du you use in your system...?
First, thanks for your reply.
Herein, we discuss plasma guns. Two used gases are argon and hydrogen.
Generally, we can know how the power of a plasma gun is. But we may rarely hear about what the energy density of the gun is.
Regards,
Justin
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06-22-2011, 02:22 AM,
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Gordon
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RE: What is the main factor for affecting the efficiency of melting the powder?
Hi Justin
to the Surface Engineering Forum.
Quote:I have a question about melting the powder. I heard a special view point from someone. He said "The powder would be melted better if the gun have higher energy density, although the power of this gun is smaller than the other gun." Is it possible?
Yes
Quote:I feel confused very much. The energy desity becomes higher and higher with increasing the power, doesn't it?
Yes to some extent, when considering the same plasma system and nozzle.
But plasma spraying a powder to form a good coating is reliant on many other factors. A lot of my experience with the higher energy plasma spraying has been with carbide based coatings. These do not actually require that much heating, but very high velocity.
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06-23-2011, 06:31 AM,
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Justin
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RE: What is the main factor for affecting the efficiency of melting the powder?
Hi Gordon
Thanks for your reply.
How about NiAl coating?
Velocity is also a reason of affecting the quality of coating.
Herein, Energy density that we discuss is related closely to the concentration of heating (power) for a plasma gun.
I don't know whether the statement exists or not.
Regards,
Justin
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07-14-2011, 07:10 AM,
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dcrawford
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RE: What is the main factor for affecting the efficiency of melting the powder?
Justin,
Just to complicate the issue for you there are other factors affecting the melting of powders:
1. Plasma flicker. I have seen cases with an F4 where there was no plasma 10% of the time due to arc strike. It was very clear during the times when there was no plasma that the particles were not melted.
2. Plasma Shape. Different torch manufactures claim their plasmas have various shapes which help particle melting. For example, the Sulzer Metco Triplex torch has a three lobed plasma. They inject the powder inbetween the lobes and are able to get a very consistent powder injection and energy transfer to the particles.
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