Every SMAW electrode carries a stamped code that tells a trained eye everything — tensile strength, welding position, flux chemistry, current type, and alloy composition. Misread it and you risk under-matched welds, hydrogen cracking, or sensitisation failure in service. Read it correctly and you’ll select the right rod the first time, every time.

The American Welding Society standardises SMAW electrode classification across three key specifications: AWS A5.1 for carbon steel, AWS A5.5 for low-alloy steel, and AWS A5.4 for stainless steel. This guide decodes all three systems in full, with comparison tables, real-world electrode examples, and the practical knowledge you need on the shop floor.

What is SMAW?

Shielded Metal Arc Welding — universally known as stick welding — is one of the oldest and most versatile arc welding processes. A consumable flux-coated electrode is clamped in a holder; striking an arc melts both the electrode core and base metal, while the burning flux coating generates a shielding gas and forms a protective slag layer over the solidifying weld pool.

The critical insight is this: it is the flux coating that determines how an electrode behaves — its arc stability, penetration, deposition rate, positional capability, current requirement, and the mechanical properties of the deposited weld metal. The AWS classification system encodes all of that into the stamped designation.

Carbon Steel Electrodes — AWS A5.1

Carbon steel SMAW electrodes follow the AWS A5.1 specification. The designation takes the form E X X X X, where each position carries specific meaning.

The ‘E’ — Electrode

The letter E simply identifies this as a consumable arc welding electrode. Every SMAW electrode starts here, regardless of material category.

Digits 1–2: Minimum Tensile Strength

The first two digits (occasionally three for higher-strength grades) express the minimum tensile strength of the deposited weld metal in thousands of psi (ksi). E60XX deposits metal with at least 60,000 psi tensile strength; E70XX gives 70 ksi; E80XX gives 80 ksi — and so on up to E120XX for ultra-high-strength applications.

3rd-to-Last Digit: Welding Position

This single digit defines which orientations the electrode can be used in. For a full breakdown of every plate and pipe position including 5G and 6G pipe, see our complete guide: A Complete Guide to Welding Positions — ISO 6947 & ASME Section IX.

Last Digit: Flux Coating Type & Current

This is the most information-dense digit in the designation. It encodes the flux chemistry, the current type (AC, DCEP, DCEN), and by extension the penetration profile and usability characteristics.

Most Used Carbon Steel Electrodes

Selecting the right electrode is not just about matching the grade — current availability, machine type, and position all factor in. For a broader framework on how to approach welding consumable selection across all processes, see our dedicated guide.

Low Alloy Steel Electrodes — AWS A5.5

Low alloy steel electrodes follow AWS A5.5. The designation builds directly on the A5.1 carbon steel format, adding an alloy suffix after a hyphen to identify the deposited weld metal chemistry.

The Alloy Suffix Groups

Stainless Steel Electrodes — AWS A5.4

Stainless steel SMAW electrodes follow AWS A5.4 and use a fundamentally different designation format: E XXX (L or H) – XX. The alloy type number replaces the tensile strength digits, carbon content is explicitly declared, and the coating/current suffix becomes two digits.

The Three-Digit Alloy Number

The L / H Carbon Suffix

Carbon content is so critical in stainless steel welding that AWS explicitly includes it in the designation — unlike carbon or alloy steel classifications. The underlying metallurgical reason is sensitisation — the formation of chromium carbides at grain boundaries that strips the surrounding matrix of its corrosion resistance.

Coating Suffix — -15, -16, -17

Side-by-Side Comparison of All Three Systems

Now that each system has been examined individually, it is instructive to place them in direct comparison. The table below summarises every structural difference between AWS A5.1, A5.5, and A5.4 designations.

Pro Tips for the Field

1 — Low-Hydrogen Electrode Storage

E7018, E8018-B2, E316L-16, and all other low-hydrogen electrode families absorb moisture from ambient air within hours of opening. Moisture in the coating converts to atomic hydrogen in the arc plasma, which then diffuses into the HAZ and can cause hydrogen-induced cracking (HIC) — often hours after the weld is complete and inspected. The risk is strongly correlated with the base metal’s carbon equivalent (CE); higher CE steels are significantly more susceptible.

2 — Always Match Filler to Base Metal

For stainless steel, never substitute E308 for E316L on 316L base metal. The molybdenum in 316 is specifically there to resist pitting corrosion in chloride environments — it cannot be substituted out. Similarly, never use a carbon steel electrode on Cr-Mo pipe: the weld will be under-matched in creep strength and may fail in high-temperature service without any visible warning.

3 — Current and Polarity First

Before striking an arc, confirm your machine’s output and polarity. E6010 will not run on AC. E308-15 requires DCEP. Running the wrong current type will cause arc instability, excessive spatter, and potential lack of fusion — a non-destructive test failure waiting to happen. If using an AC transformer on site, select -16 suffix stainless or an E6011 carbon steel electrode.

4 — Read the Data Sheet

The AWS designation tells you the minimum. The manufacturer’s data sheet tells you everything else: diffusible hydrogen levels, impact values at temperature, interpass temperature limits, actual deposition rate, and suggested amperage range. For code work, the data sheet is a job-site document, not optional reading.