Military Vehicles, March 1997,: Re: What's Thermal Spray?
Re: What's Thermal Spray?
G740@aol.com
Tue, 25 Mar 1997 21:21:15 -0500 (EST)
There are several different types of Thermal spray. First, there is spray
and fuse type. This involves a torch, of special design, and oxy/acet gas.
The part is heated up to a dull red heat and a powdered metal is applied
thru the torch and basically brazed on. The second type also uses a torch of
special design and the same gas but the powdered metal alloy is mechanically
bonded to the part similarly to weld spatter. This system starts at about
$5000 and can go to $20,000 depending on options. There is wire arc spray
that uses an electric arc and a consumable wire which is propelled onto the
part and uses the same mechanical bond. There is plasma spray which uses a
very high temp. electric arc,(60-80kw), the same mechanical bond takes
place. Plasma is often used for applying ceramic materials. Lastly, there
is HVOF. High velocity oxy fuel. This is the cadillac way of applying
metallic coatings. Systems run upwards of $70,000. Mechanically bonded
coatings but they have the highest bond strength of all the sysems. Lowest
amount of porsity of all systems. Many types of alloys can be applied
including nickel, cobalt, iron, stainless etc. As an example over 1000 parts
of a jet engine are thermally sprayed. It can be used as a repair process
for worn areas or it can be used to apply a protective layer both from
corrosion and heat or abrasive wear.
I hope this hasn't bored all of you but it is a great way of reclaiming the
parts for our vehicles which have worn out. I have been in this business for
15 years and it has saved me numerous times. If you still don't quite get
this let me know and I'll go into more detail. Thanks for listening. John