Combustion wire spray process for corrosion protection

Combustion wire spray process uses a set of drive rolls powered by an air turbine or an electric motor to draw a metal alloy wire through combustion spray gun. At the gun nozzle, fuel gas of acetylene, propane or MAPP is combined with oxygen in precise volumetric proportions by using a siphon plug and ignited to develop a flame that is then shaped at the gun’s air cap by compressed air. The metal wire is fed concentrically in the flame, melted and atomized by the compressed air and molten drops are propelled towards a prepared surface where they solidify and bond to the substrate to develop a coating.

Combustion wire spray is a wide choice for machine element repair and corrosion coatings. Hard or soft wires can be used.

Characteristics of combustion wire spray process

·         A range of alloys and pure metals for restoration, corrosion coatings and other applications

·         Installations from economical manual systems to fully automated production systems

·         Portable for onsite coatings

·         High spray rates with low gas use

·         Coatings can be machined to final dimensions and finish

·         Covering areas where coating is possible

·         Coating of internal shapes

·         Simple to use and maintain

Process

An electric arc spray wire process involves the use of two metallic wires, often the same composition. Both wires are electrically charged with opposing polarity and are supplied into the arc gun at matched and controlled speeds. When the wires are placed together at the contact location, the opposite charges on the wires produce sufficient heat to continuously melt the wire tips. Compressed air atomizes the molten material and accelerates it on the sample surface to produce the coating.

In electric arc wire spray, the coating weight that can be accumulated per unit of time is a function of the electrical power of the system and density and melting point of wire. Considering the columnar strength of the wire, the push, pull mechanisms can be used to feed the wire at a constant rate.

Attributes of electric arc wire spray

A range of alloys and pure metals for restoration, corrosion coatings and other purposes in solid wire or cored wire

Compact and self-contained systems

Outstanding portability for on-site coatings

Does not need any process water or gases except compressed air

High spray rates

Develops coatings that are easy to machine

Coating of internal shapes

Simple to use

Thermal spray wires have been available for decades. The wires work in multitude of applications successfully. Wire technology has revolutionized double wire arc spray. Cored wires are developed by creating a thin strip of metal in a wire, at one point in the process material is added to the center of the strip as it is being formed, the material can be metallic elements or non-metallic like carbides. Thermal spray wire materials have a proven history of excellent spray ability and are treated to improve feed ability and productivity.