Thermal spraying is used for new production, as well as repair and maintenance. In repair and maintenance, the method often offers cost advantages compared to buying new parts. It is not unusual for the lifetime of the renovated part to increase, leading to longer intervals between preventive maintenance.
Thermal spraying is a common expression for several spraying methods, one of which is flame spraying. During spraying, the additive material, which can take the form of powder, wire or sticks, is heated to melting temperature or a practically melted condition. The heated material is finely distributed and sprayed, by means of a gas flow, towards the surface of the piece (the substrate) where it fastens and solidifies. The sprayed surface can be used as is, or worked into the correct dimensions.
A component’s surface is what most often limits its lifetime, since it is the surface that is exposed to wear, corrosion and/or high temperatures. Materials and thermal spraying methods are available for practically every surface quality.
Flame spraying with the correct additive material can improve the surface’s resistance to corrosion, wear and high temperatures. You can achieve surfaces with high or low friction, or alter the surface’s conductivity. Damaged surfaces can be repaired and faulty parts can be corrected to the right dimensions.
The choice of fuel gas depends on the melting temperature of the additive material and the type of spraying equipment used. For spraying polymers, it may be sufficient to use propane mixed with compressed air, in order to achieve a sufficiently high temperature. For the highest temperature, acetylene mixed with pure oxygen should be used.