MIG welding has become the leading welding process because of its ease of use, range of applicable mechanical properties, and high deposition rate.
After almost four decades, MIG welding wire has basically retained the same characteristics it was born with:
• Wire made of steel
• A well-defined analysis with copper-coating
• Generally supplied on small reels or spools
The Marathon PacTM bulk wire package is the only really significant innovation to be introduced over the last decade. This package is ideal for robotics and automated welding processes.

Why is copper coating often used on MIG/MAG Wire?
A MIG wire must satisfy three main requirements:
• Metallurgical: The wire must have the correct chemical analysis
• Electrical: The wire must have good electrical conductivity to enable the current to flow with more ease through the contact tips and assure good arc stability
• Mechanical: The wire must feed smoothly through the feed system from the feed rollers through the liner to the contact tips.  The copper coating on the surface of the wire satisfies the last two of these requirements in practical terms and protects the wire from environmental oxidation. Copper coating also permits an easier and faster drawing cycle during manufacturing, thereby enabling the wire manufacturer to obtain higher productivity and lower costs.  However, from an objective point of view, copper coating is regarded as a necessary evil.

Negative Aspects of Copper Coating on MIG Wire
Considered one of its positive aspects, but also one of its weaknesses, copper coating acts as a lubricant to facilitate the passage of the wire during feeding. Depending on the level of copper adherence to the wire surface, the continuous passage of the wire through feed rolls and liners causes the loss of copper particles. This results in uneven wire feeding, blockage of the torch liner, and other subsequent problems, often causing welding defects, arc instability, the need for repairs, cycle interruptions, cost increases, the loss of productivity, and so on. To eliminate this problem, frequent maintenance is required. Once again, this
results in cycle interruptions, extra time and costs, and, ultimately, the loss of productivity.  From a metallurgical point of view, it is known that copper, when added to the weld pool, even if it comes from the wire surface, may produce negative effects such as an increased risk of hot cracking, and reduced impact properties. The environmental impact of copper coating on MIG wire is often overlooked. The copper that comes from the welding fumes is environmentally harmful. Other harmful by-products are also generated during the manufacturing process of copper coated wire.

The Solution: OK Autrod 12.50 non-copper-coated MIG Wire
The negative aspects of copper coated MIG wire inspired ESAB to develop OK Autrod 12.50, a non-copper-coated ER70S-6 wire.
The guiding principle for the development of OK Autrod 12.50 was very simple:  Eliminate the negative effects of copper coating without losing any of the ideal characteristics of a good MIG/MAG wire.
In-depth research, extensive experiments, and the development of sophisticated process technology have resulted in an exclusive manufacturing procedure, producing a wire that is comparable and even better than copper-coated wire.  Compared with traditional copper-coated wires, OK Autrod 12.50 provides smoother, uniform feeding, as there are no copper particles the wire can shed. This guarantees cleanliness and a long service life for the liners and the entire feed system — up to three times longer than when a standard copper-coated wire is used. As a result, the time wasted on cleaning and maintenance is reduced and productivity is improved. Another important characteristic of OK Autrod 12.50 is its arc stability. The weld is practically spatter-free, which results in enhanced quality and fewer welding defects. This is obviously a benefit in terms of time-savings and reduced rework costs.  Finally, OK Autrod 12.50 has no harmful impact on the environment or on the welder, since no copper fumes develop from the wire surface during welding. The ease of use provides the welder with improved comfort, quality satisfaction, and greater efficiency.

OK Autrod 12.50 - The Best Choice for MIG/MAG Welding
• The arc-stability characteristics and improved feedability of OK Autrod 12.50 make it ideal for robotic or automated processes, where welding steadiness and uniformity are essential in order to avoid welding defects and very expensive cycle interruptions
• Less post-weld cleanup means less grinding
• The absence of copper on the wire surface results in a cleaner deposit and avoids the metallurgical risks that can be induced by the increase in copper in the weld pool rod 12.50