Thermal spraying is used for new production as well as repair and maintenance. In repair and maintenance, the method often offers cost advantages compared with buying new parts. Moreover, it is not unusual that the life-time of the renovated part will increase, leading to increased intervals between preventive maintenance.
Thermal spraying is a common expression for several different spraying methods, one of which is flame spraying. When spraying, the additive material, which can be in 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 to the correct dimensions.
It is often a component’s surface that limits the life-time since it is exposed to wear, corrosion and/or high temperatures. There are materials and thermal spraying methods 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.
