Every stick welding rod has a code printed on its coating, and once you know what each character means, you can identify the rod’s strength, welding position, coating type, and current compatibility at a glance. The system follows a standard set by the American Welding Society (AWS), and it works the same way across manufacturers. A typical code looks like E7018 or E6011.
What the “E” Means
The letter “E” at the beginning stands for electrode. It simply tells you this is a consumable stick electrode designed for arc welding. Every standard mild steel stick rod starts with this letter, so it’s the easy part.
The First Two or Three Digits: Tensile Strength
The first two digits of a four-digit code (or first three digits of a five-digit code) tell you the minimum tensile strength of the weld metal in thousands of pounds per square inch (PSI). This is the amount of pulling force the finished weld can withstand before it breaks.
- E60xx = 60,000 PSI
- E70xx = 70,000 PSI
- E100xx = 100,000 PSI
- E110xx = 110,000 PSI
For most structural and general-purpose work, 70,000 PSI rods (the E70xx family) are standard. The 60,000 PSI rods are common for maintenance, repair, and thinner materials. Higher-strength rods exist for specialized applications like heavy equipment or high-strength steel.
The Next-to-Last Digit: Welding Position
The third digit in a four-digit code (or fourth in a five-digit code) tells you which positions you can weld in with that rod. There are three possible numbers here:
- 1 = All positions (flat, horizontal, vertical, overhead)
- 2 = Flat and horizontal only
- 4 = Flat, horizontal, vertical down, and overhead
If you’re doing any kind of field work or structural welding where the joint isn’t always beneath you, a “1” in this position is what you want. Rods with a “2” are designed for situations where gravity is working with you, not against you.
The Last Digit: Coating and Current Type
The final digit is the most information-dense. It tells you two things at once: the type of chemical coating (flux) on the rod and what electrical current the rod is designed to run on. This digit ranges from 0 to 8, and each number maps to a specific combination of flux chemistry and polarity. Rather than memorizing all of them, knowing the most common ones covers the vast majority of rods you’ll encounter in practice.
A “0” means a cellulose-based coating designed for DC current with the electrode on the positive side (reverse polarity). A “1” also has a cellulose coating but can run on AC as well. A “3” indicates a rutile (titanium dioxide) coating that runs on AC or DC. An “8” means a low-hydrogen, iron powder coating that runs on AC or DC reverse polarity. These last-digit differences have real effects on how the arc behaves, how much spatter you get, how deeply the weld penetrates, and how easily the slag peels off.
Putting It All Together: E7018
Take the most popular structural welding rod, E7018, and break it down piece by piece:
- E = Electrode
- 70 = 70,000 PSI tensile strength
- 1 = All-position welding
- 8 = Low-hydrogen, iron powder coating; AC or DC reverse polarity
That single code tells you the rod produces a high-strength weld, works in any position, and uses a low-hydrogen flux that minimizes the risk of cracking in thick or high-strength steel.
Common Rods and What They’re Best For
Knowing the numbering system is useful, but knowing how the most popular rods actually perform saves you from grabbing the wrong one.
E6010 delivers deep penetration and can dig through rust, oil, paint, and dirt. Many pipe welders rely on it for root passes. It runs on DC only, produces a forceful, aggressive arc, and the slag can be tricky to remove. This is a rod for experienced hands working on dirty or rusty metal.
E6011 performs almost identically to the 6010 but adds AC capability. That makes it the go-to for maintenance and repair work when you only have a basic AC buzz box available. It cuts through corroded metal the same way a 6010 does.
E6013 produces a soft, gentle arc with minimal spatter and moderate penetration. The slag comes off easily. It’s best suited for clean, new sheet metal and thinner materials where you don’t want to blow through the base metal. Not the rod for dirty or rusty surfaces.
E7018 is the workhorse for structural steel. It creates a smooth, quiet arc with minimal spatter and produces strong welds with high impact toughness, even in cold weather. It works on carbon steel, high-carbon steel, low-alloy steel, and high-strength steel. Many welders consider it the default choice for thick metals and code-quality work.
Low-Hydrogen Rods Need Special Storage
Any rod ending in 5, 6, or 8 (the low-hydrogen family, including the popular E7018) requires careful storage because the flux coating absorbs moisture from the air. Moisture introduces hydrogen into the weld, which can cause cracking, especially in thick or high-strength steel.
Unopened containers should be stored in a dry area. Once opened, these rods need to go into a holding oven set 50°F to 250°F above ambient temperature. If the rods have been left out and may have picked up moisture, they can be reconditioned by baking at 500°F to 800°F for one to two hours. Always check the manufacturer’s recommendations for your specific rod, but those temperature ranges from ASME specifications cover the E7018 family and its equivalents.
Rods like E6010, E6011, and E6013 are more forgiving. Their cellulose or rutile coatings don’t have the same moisture sensitivity, so standard dry storage is typically enough.
How to Identify a Rod Without Packaging
If you find loose rods without their original box, look at the bare grip end of the electrode. AWS and ASME codes require the alphanumeric classification to be stamped or printed on the coating within two inches of the grip end. This marking is on every individual rod, not just the packaging.
Some older resources mention color-coded dots or bands on the rod ends, but color coding varies by manufacturer and isn’t standardized across the industry. A brown dot might mean E6013 from one company and something different from another. The printed classification on the rod itself is the only reliable identification method. If the print has worn off and you can’t identify the rod, it’s safest not to use it for critical work.
Stainless Steel and Specialty Rod Codes
The system described above covers mild steel and low-alloy steel electrodes under AWS specification A5.1. Stainless steel rods follow a different format. A stainless rod might be labeled E308L-16, where 308L identifies the stainless steel alloy (the “L” means low carbon for better corrosion resistance) and the -16 suffix indicates the coating type and current.
Aluminum filler metals use an “ER” prefix, where E stands for electrode and R stands for rod, meaning the material can be used as either. An ER4043, for example, is a common aluminum filler alloy. Cast iron electrodes often carry an “ENi” prefix, indicating a nickel-based filler designed to be machinable after welding. These specialty codes follow their own AWS specifications, but the underlying logic is the same: each part of the code tells you something specific about the material and how to use it.