Shielded Metal Arc Welding Parameters and Techniques

摘要

Shielded metal arc welding (SMAW) has been a popular process for joining metals for many years. Its economical operation, versatility and easy use in the field have contributed to its appeal. Depending on the choice of electrodes, SMAW can be performed on either AC or DC polarity. The arc is most steady and the transfer the smoothest with DC polarity. Direct current electrodes perform well at low amperage and because of this are often selected for welding thin metals. The DC electrodes are also preferred for vertical and overhead welding. Most covered electrodes operate best with electrode positive (reverse polarity), which produces the deepest penetration. Electrode negative operation might produce a higher melting rate.