What type of current do welding machines typically use for SMAW?

In Shielded Metal Arc Welding (SMAW), welding machines are versatile and can utilize both Alternating Current (AC) and Direct Current (DC). This flexibility allows welders to select the appropriate current type based on the specific requirements of the job, including the type of electrode used, the position of the weld, and the type of material being welded.

Using AC is common in SMAW, especially with certain types of electrodes designed for it, as it can help prevent arc instability and provide a smoother weld. Conversely, DC is often preferred for its ability to produce a more stable arc, especially when working with materials that require better penetration and control, such as stainless steel or during vertical welding positions.

The choice of current can significantly affect the welding process, arc stability, and the quality of the welds produced, making the ability to use both AC and DC essential for comprehensive welding practices. Therefore, the correct answer reflects the versatility inherent in SMAW techniques.