<p>Wire rods used to produce metal inert gas (MIG) wire, typically ranging from 5.5 to 12&#xa0;mm in diameter, are generally produced by hot rolling continuously cast billets in wire rod mills. These rods are subsequently processed in wire drawing plants, where they are drawn into wires with reduced cross sections suitable for welding applications. The most commonly used steel grade in MIG is ER70S-6, a premium mild steel featuring low carbon content (0.06–0.08 wt.%), relatively high manganese (1.40–1.50 wt.%), and low sulfur (maximum 0.020 wt.%). This composition is engineered to deliver high-quality welds and consistent performance across a range of applications—from high-speed, spray transfer welding to low-speed, short-arc operations. The quality of drawn wires is critically important, as any material defects or abnormalities can lead to significant productivity losses and potential customer claims. In the present study, wire samples that failed during the wire drawing process were collected and analyzed to determine the underlying causes of failure. Microstructural analysis revealed that the root cause of wire breakage originated from poor weld quality at the wire joints. Specifically, improper fusion at the welded ends of the wire rods—introduced during the customer’s welding process—was identified as the primary defect. This highlights the need for stringent control and improved practices in weld joint preparation to ensure proper fusion and mechanical integrity of the wires during downstream processing.</p>