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MG-50 (AWS A5.18 ER70S-G) MG-50 is one of the most popular solid wires for gas metal arc welding of mid- and heavy-thick mild steel and 490N/mm2-class high strength steel with C02 shielding. Steel structures, construction machin- ery, and industrial machinery are typical applica- tions of MG-50. A Stable Arc at High Currents A stable arc at high currents is the most important feature of MG-50. If a general solid wire is used at high currents with CO^ shielding, it may generate much spatter, undercut and irregular bead appearance because of an unstable arc or irregular transfer of molten metal in large drops from the tip of the solid wire across the arc. In contrast, MG-50 generates less spatter and undercut with smoother bead appearance due to smoother molten metal transfer in smaller drops, even though the transfer mode is of globular transfer. This is owing to the specific chemical elements contained in MG-50 a small amount of titanium in particular plays such an important role. Wide Bands of Welding Currents and Arc Voltage
MG-50 performs over wide bands of welding currents
and arc voltage, exhibiting the excellent arc stability.
Figure 1 shows the proper current and voltage ranges
for 1.2- and 1.6-mm (]) wire.
Fig. 1 - Proper ranges of welding currents and arc voltage for MG-50 (1.2mm, 1.6mm) |
High Deposition Rates Contribute to High Welding Speeds The use of a higher current produces a higher deposition rate, as in Fig.2, thereby increasing welding speeds, which can decrease welding costs. This is the most important benefit of MG-50 derived from its outstanding usability at high currents in flat and horizontal fillet positions. However, to ensure the minimum tensile strength of 490N/mm2, the procedure should be controlled with heat input of 30kJ/cm max and pass-to-pass intervals causing a interpass temperature of 250°C max.
Fig. 2 - Deposition rates of MG-50 (wire extension: 15mm for 1.2mm; 20mm for 1.6mm) Good Wire-Feeding and Seam-Tracking Minimize Downtime in Robotic Welding The smooth surface and consistent cast and helix of MG-50 ensure smooth wire-feeding and seam-tracking along welding lines, thereby minimizing downtime in robotic welding and other automatic welding processes. Because of such invaluable characteristics, MG-50 has earned a consistent reputation from users as in the steel structure, construction machinery and industrial machinery industries.
Fig. 3 - MG-50 maintains a persistently high reputation in the steel structure industry |