SMAW

From GAWDAwiki

Shielded Metal Arc Welding (SMAW), also known as Manual Metal Arc (MMA) welding or simply stick welding, is a method of arc welding in which metals are melted and joined when an arc is heated between a covered metal electrode and a work piece. Protective shielding gas and slag are provided by the flux, or outer coating of the electrode, while filler metal is provided by the electrode’s core.^[1]

SMAW setup

Power Sources

SMAW power sources are constant current, and may be either AC (alternating current) or DC (direct current), depending on the electrodes being used.¹ Direct current reverse polarity welding is preferred over AC for most SMAW applications due to easier starts and out-of-position welding, smoother arcs, fewer arc outages and less sticking.^[2]

Diagram of arc and weld area in shielded metal arc welding

Electrode Designation

SMAW electrodes have a standard coding system to identify them. There are three parts to the electrode designation.

An E6010 electrode would be defined as follows:

“E” stands for electrode.

“60” or the first two digits (E60XX) on the electrode are an abbreviation that represents a minimum of 60,000 pounds of tensile strength per square inch of weld. The first two digits require adding three zeros like XX,000 to identify the minimum weld strength of the electrode.

“10” or the last two digits (EXX10) designate the amount of flux, shielding, and or powdered filler metal added to the coating of the electrode.

Some of the most common Stick welding electrodes and there weld characteristics are:

E6010 deep penetration works well in all positions and is excellent on dirtier metals.
E6011 deep penetration works well in all positions and is excellent on dirtier metals.
E6013 mild penetration works well in all positions and needs a cleaner joint.
E7018 mild penetration works well in all positions and works best on clean metals.
E7024 mild penetration works well in the flat positions and needs a clean joint.^[3]

Striking an Arc

In the scratch-start technique, an electrode is dragged across a work piece in the same way that one might light a match—the electrode is lifted immediately after contact with the work piece is made.
In the tapping technique, an electrode is brought straight down onto a work piece and immediately lifted slightly.
If the electrode is lifted too high in either technique, the arc will go out. If the electrode sticks to the work piece, it can be freed with a quick twist.¹