Arc Wire

Arc Wire

Arc wire brings the operational simplicity and portability of MIG welding technology to the field of thermal spray. The result is a system capable of applying a quality surface treatment at virtually any location.

Arc Wire thermal sprayAdditionally, the high feedstock capacity of the arc wire system makes it ideal for coating large areas, such as structural surfaces and large rolls.

Common Applications

  • Journal and Bearing Repair and Buildup
  • Roll Resurfacing
  • Exposed Outdoor Structure Protection

Method

Arc wire thermal sprayed coatings bear a similarity to flame wire coatings in that both are applied by completely melting and atomizing a wire feedstock before projecting the droplets onto the work surface. Rather than using an oxy-fuel flame to liquefy the metal, an arc wire system uses the heat of an electric arc. In a twin wire system, this arc is struck at the merging tips of two oppositely charged wires made of the material to be sprayed. The point of intersection of these wires is positioned directly in front of a jet of compressed air. As the heat from the arc melts the wire, the jet blows molten droplets forward onto the part. A mechanical feed mechanism pushes both wires forward to maintain the arc and the flow of material.

 

Practice

The compressed air jet used in the arc wire system tends to promote oxidization of the molten particulate more readily than other systems using inert carrier gasses. As a result, photomicrographs of arc wire-sprayed coatings tend to reveal a higher percentage of oxidized material than those of coatings applied by plasma or HVOF systems. The added oxide content also increases the hardness of these coatings over those of other processes. Though this oxidization may be a concern in some applications, the high mechanical interlock of particles in an arc wire coating often makes this chemical feature irrelevant. Alternatively, nitrogen may be used as an atomizing gas to minimize oxide formation in the deposit.

 

Arc wire also affords the unique opportunity to create custom 50-50 pseudo-alloy coatings. The arc must be struck between two wires, but the wires need not necessarily be of the same material. By using two wires of differing metals, the coating applied will be a blend of these. Though this feature is seldom requested, it is only possible through the use of an arc wire system.