Detonation syringes

The detonation spraying or flame shock spraying is a thermal coating process . It differs from flame spraying in that it is discontinuous.

In quick succession, to about 10 Hz, in a be cannon well-dosed amounts mentioned pipe oxygen, fuel gas, for. B. acetylene or propane, and coating powder caused by an ignition device to explode. The hot gas entrains the powder particles and heats them up. On the prepared material surface a dense, firmly adhering layer of the powder material, z. B. tungsten carbide. After each explosion, the pipe is purged with nitrogen .

Flame temperatures over 3000 ° C, particle speeds over 600 m / s, and application rates of 3 to 6 kg / h are achieved. These are heated in the flame front and hit a prepared workpiece surface at high speed in a focused beam. Applications for this technology are, for example, turbine rotors and plungers . In the meantime, however, the process has largely been replaced by high-speed flame spraying , which also offers very good layer qualities with a higher application rate.

literature

Hans J. Fahrenwaldt, Volkmar Schuler: Practical knowledge of welding technology: materials, processes, production , Vieweg + Teubner, 2011, ISBN 978-3-8348-1523-1 , limited preview in the Google book search.