How does Electric Arc Spraying work?
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Sulzer Metco
Electric arc spraying (EASP) is a thermal spraying process that uses an electric arc between two consumable electrodes of the
surfacing materials as the heat source. A compressed gas atomizes and propels the molten material to the workpiece. The two
consumable electrode wires are fed by a wire feeder to bring them together at an angle of approximately 30 degrees and to maintain
an arc between them. A compressed air jet is located behind and directly in line with the intersecting wires. The wires melt in the arc
and the jet of air atomizes the melted metal and propels the fine molten particles to the workpiece. The power source for producing
the arc is a direct-current constant-voltage welding machine. The wire feeder is similar to that used for gas metal arc welding
except that it feeds two wires. The gun can be hand held or mounted in a holding and movement mechanism. The part or the gun is
moved with respect to the other to provide a coating surface on the part.
Coating Characteristics
- The layers of electric-arc process are characterized by an outstanding adhesion, yet not reached in the flame spraying. The spraying particles weld with the basic material.
- Excellent for applications that require heavy coating build-up or for large surfaces. Arbitrarily strong layers from 0.2mm to 20mm can be laid on.
- Can be sprayed at extremely high rates of speed.
- The sprayed coatings can hardly be differentiated by colour from the basic material.
- Good machinability of the oxide-poor sprayed coatings.
- Electric-arc sprayed coatings have approximately 3 times higher strength and smaller contraction strain than flaming sprayed coatings.
- Metal sprayed coatings are micro porous, which has big advantages for sliding bearings and Simmerring seats.
- You can adjust coating characteristics, such as coating hardness or surface texture.
- Independent of the basic material can all materials be coated e.g. 13% chromium steel on aluminium
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