Hayden Corporation

Flame Spray coatings

Flame Spray coatings

Flame spray coatings are a surface enhancement that can be applied quickly and easily to many types of components. The process involves using a oxy-acetylene flame to spray metallic or composite coatings onto surfaces. This coating can provide enhanced traction, improved thermal conductivity, cathodic protection, and other improvements. Flame spray coatings are typically used in industrial and commercial applications but can also be used for general repair and maintenance tasks. One of the key advantages of flame spray coatings is the portability of the equipment. Flame spray coatings can easily be applied on-site for applications that are too large or costly to ship.

Flame Spray Method

Flame spraying actually describes two similar but different methods: flame spraying of wire and flame spraying of metal powder. All flame spray guns, however, perform the same essential function of heating and projecting the coating material through the use of an oxy-fuel flame and a pressurized carrier gas jet.
Materials sprayed with this process come in both wire (flame wire process) and powder (flame powder process) forms, depending on the gun used. In either case, the gun serves to melt and atomize or soften the material as it is fed into the flame, and eject the soft or molten particulate in a directed stream through the gun’s nozzle.

Flame Spray Practice

Flame spray guns typically require very little additional equipment. Most powder-fed guns have a hopper built into the gun body. Others use a small external powder feed unit. Wire guns usually have a mechanism built into the gun body to guide the feeding of wire and regulate its speed. Typically, only supply lines for oxygen, fuel, and, occasionally, compressed air are required. Beyond the obvious ease of transport and installation this feature affords, this simplicity also significantly reduces setup time and the margin for operator error.
The relatively low particle velocity of the flame spray process leaves a coating of moderate but not outstanding density. As a result, flame sprayed coatings of self-fluxing alloys are often candidates for spray and fuse processes where the additional fusing stage can allow the coating to flow more freely and fill many of the voids that the spray process may have left.