By Kevin Beck, Updated Mar 24, 2022

Welding is the art of joining metals by heating them to a molten state, allowing the pieces to fuse and solidify into a strong, lasting bond. Whether working with the same metal or disparate alloys, welds provide the structural integrity required for buildings, bridges, and countless everyday applications.

Arc welding relies on an electric arc produced by a current‑driven electrode. The 7018, or E7018, electrode is one of the most widely used in industrial settings, prized for its strength and versatility.

Welding Methods in Practice

• Arc welding: The industry standard for large‑scale projects. Common electrodes include the 7018 and 6010. Peak temperatures can reach 7,000°F.
• Oxy‑fuel gas welding: Uses heated gas to create a flame for welding. Oxyacetylene and oxyhydrogen are typical fuel combinations.
• Resistance welding: Also known as spot welding, this technique heats sheet metal by passing a current through it, exploiting electrical resistance.
• Solid‑state welding: Bonds metals without melting, using controlled temperature and pressure.
• Advanced techniques: Electron‑beam, slag, laser‑beam, and thermite welding represent cutting‑edge applications.

Stick (Shielded Metal Arc) Welding Explained

Stick welding—technically called Shielded Metal Arc Welding (SMAW)—employs a consumable electrode that melts to form the weld metal. A protective gas film generated by the electrode shields the arc from atmospheric contamination. As the electrode is consumed, it also acts as filler material, enhancing joint strength during cooling.

Classifying Welding Electrodes

Electrodes are identified by a three‑ or four‑digit code. For four‑digit numbers, the first two digits represent the minimum tensile strength in thousands of psi. For example, “61” denotes 61,000 psi (61 ksi). The third digit indicates the welding position (1 for any position, 2 for flat, 4 for overhead). The final two digits convey coating type and recommended polarity/current (AC or DC).

Decoding the 7018 Electrode

The “E” in E7018 signifies an electrode for arc welding. The “70” indicates a minimum tensile strength of 70,000 psi. The “1” confirms usability in any welding position, while “18” signals a low‑hydrogen coating suitable for DC current. This combination delivers robust, low‑defect welds across a range of industrial scenarios.