What Do the Numbers on Arc Welding Rods Mean: Explained Clearly
A welding rod marked E7018 is not labeled with a random product code. Each part identifies the electrode, its minimum tensile strength, approved welding positions, and the coating or current type. Reading those digits helps you choose a rod that matches the metal, joint position, and welding machine.
Understanding what do the numbers on arc welding rods mean is especially useful when a job calls for a specific classification such as E6010, E6013, or E7018. The marking follows an American Welding Society system for many shielded metal arc welding, or stick welding, electrodes.
What the Rod Code Identifies
A common AWS stick-electrode classification looks like this:
E7018
- E means electrode.
- 70 means a minimum tensile strength of 70,000 pounds per square inch, or 70 ksi.
- 1 identifies the approved welding position.
- 8 identifies the coating type and recommended welding current characteristics.
The same pattern applies to many carbon-steel electrodes, including E6010, E6011, E6013, E7014, and E7018. Some classifications use five digits after the letter E. In that case, the first three digits describe tensile strength. For example, E11018 represents a 110 ksi electrode, followed by the position and coating digits.
Meaning of the First Letter
The first character is normally E, which stands for electrode. In this context, it identifies a covered electrode used for shielded metal arc welding.
The coating around the steel core wire creates shielding gas and slag as the rod melts. The coating also affects arc behavior, penetration, slag removal, moisture sensitivity, polarity, and the positions in which the rod can be used.
Meaning of the Strength Numbers
The first two or three numbers after E state the electrode’s minimum tensile strength in ksi. Tensile strength describes the pulling force the deposited weld metal can withstand before it breaks.
| Electrode | Strength digits | Minimum tensile strength |
|---|---|---|
| E6010 | 60 | 60,000 psi |
| E7018 | 70 | 70,000 psi |
| E9018 | 90 | 90,000 psi |
| E11018 | 110 | 110,000 psi |
These numbers do not directly state the yield strength, hardness, impact toughness, or suitability for every application. They identify the required mechanical performance of the deposited weld metal under the applicable classification standard.
For example, E7018 has a minimum tensile strength of 70 ksi. That does not mean every part of the rod, including the mild-steel core wire, has exactly that strength. It refers to the weld metal produced when the electrode is used and tested according to the classification requirements.
Meaning of the Position Number
The next digit identifies the welding positions allowed by the electrode classification.
| Position digit | Meaning |
|---|---|
| 1 | All positions |
| 2 | Flat and horizontal fillet welds |
| 3 | Flat position only |
An electrode ending in 1, such as E6010 or E7018, is classified for all positions. This includes flat, horizontal, vertical, and overhead work, although the welder may need to change amperage, travel speed, and technique for each position.
An electrode with a 2 in this position-designation spot is intended for flat welds and horizontal fillet welds. An electrode with a 3 is limited to flat welding. E7024 is a common example of an electrode designed primarily for flat and horizontal fillet work.
The position digit does not tell you how easy the rod is to use. It only identifies the positions covered by the classification. A rod approved for all positions can still require careful technique, especially for vertical or overhead welding.
Meaning of the Last Digit
The final digit identifies the electrode’s coating family and the type of welding current or polarity used for the classification. This digit is read together with the previous digits, not as a standalone quality rating.
| Ending | Common coating description | Typical current or polarity | Common example |
|---|---|---|---|
| 0 | High-cellulose sodium | Usually DC electrode positive | E6010 |
| 1 | High-cellulose potassium | AC or DC electrode positive | E6011 |
| 2 | High-titania sodium | AC or DC, depending on classification | E6012 |
| 3 | High-titania potassium | AC or DC, depending on classification | E6013 |
| 4 | Iron powder and titania | AC or DC, depending on classification | E7014 |
| 5 | Low-hydrogen sodium | Usually DC electrode positive | E7015 |
| 6 | Low-hydrogen potassium | AC or DC electrode positive | E7016 |
| 8 | Iron powder and low-hydrogen potassium | AC or DC electrode positive | E7018 |
The coating controls important characteristics such as arc stability, penetration, slag appearance, weld profile, and the amount of hydrogen introduced into the weld. “Low hydrogen” electrodes are used when hydrogen-related cracking is a concern, but they must be stored and handled according to the manufacturer’s instructions.
The table gives common interpretations for carbon-steel electrodes. The exact current options and operating limits can vary by classification and manufacturer. The package label or product data sheet is the final reference for amperage range, polarity, and permitted current.
Common Rod Numbers Explained
E6010
E6010 is an all-position electrode with a minimum tensile strength of 60 ksi. Its high-cellulose sodium coating produces a forceful, penetrating arc and a fast-freezing slag. It is commonly associated with DC electrode-positive welding and is often selected for root passes, pipe work, and situations requiring strong penetration.
Broken down, E6010 means:
- E: electrode
- 60: 60 ksi minimum tensile strength
- 1: all positions
- 0: high-cellulose sodium coating, generally used with DC electrode positive
E6011
E6011 also has 60 ksi minimum tensile strength and is classified for all positions. Its high-cellulose potassium coating allows it to operate on AC as well as DC electrode positive. It is often considered when the welding power source does not provide the DC output preferred by E6010.
E6013
E6013 is a 60 ksi, all-position electrode with a high-titania potassium coating. It generally produces a smooth arc, moderate penetration, and an easily removed slag. It is commonly used for general-purpose fabrication and repair, but the manufacturer’s instructions should still be checked for exact current and polarity settings.
E7018
E7018 is a 70 ksi, all-position electrode with an iron-powder, low-hydrogen potassium coating. The final 8 identifies that coating and its associated current characteristics. E7018 is widely used for structural and general fabrication applications where stronger weld metal and low-hydrogen practice are important.
Because E7018 is a low-hydrogen electrode, moisture control matters. Damp or improperly stored rods may not provide the intended low-hydrogen performance. Follow the package instructions for storage, exposure time, and rebaking requirements rather than assuming all E7018 rods can be treated identically.
E7024
E7024 provides 70 ksi minimum tensile strength. The 2 indicates flat and horizontal fillet positions, while the 4 identifies an iron-powder, titania-type coating. Its design supports high deposition rates in suitable flat or horizontal welds, but it is not an all-position electrode.
What the Numbers Do Not Tell You
The classification does not tell you the rod diameter. A package may identify a product as 1/8-inch E7018 or 3/32-inch E6013, but the diameter is listed separately from the AWS classification.
The numbers also do not give the correct amperage by themselves. Amperage depends on electrode diameter, classification, welding position, joint design, machine characteristics, and the manufacturer’s operating range. A larger-diameter rod typically requires more current, but the package data remains the controlling reference.
The classification does not guarantee that a rod is suitable for every base metal. The electrode must be compatible with the material, service conditions, required strength, applicable welding code, and joint procedure. Stainless-steel, hardfacing, cast-iron, and other specialty electrodes may use different AWS classification systems and additional letters or numbers.
How to Read a Rod Marking
- Find the letter E and confirm that the product is a covered electrode classification.
- Read the first two or three digits to identify minimum tensile strength in ksi.
- Read the next digit to determine the approved welding position.
- Read the final digit to identify the coating family and general current characteristics.
- Check the package for rod diameter, amperage range, polarity, storage instructions, and any supplementary classification information.
For example, E7018 can be read as “electrode, 70 ksi, all positions, iron-powder low-hydrogen potassium coating.” E6013 means “electrode, 60 ksi, all positions, high-titania potassium coating.” That short interpretation supplies the basic information needed before selecting machine settings.
Frequently Asked Questions
What does E6013 mean on a welding rod?
E6013 identifies a covered electrode with 60 ksi minimum tensile strength, an all-position classification, and a high-titania potassium coating. It is commonly usable with AC or DC, but the exact polarity and amperage range should be confirmed on the package.
What does E7018 mean on a welding rod?
E7018 means 70 ksi minimum tensile strength, all-position capability, and an iron-powder low-hydrogen potassium coating. It is generally used with AC or DC electrode-positive current, subject to the manufacturer’s instructions.
Does a higher number mean a better welding rod?
No. A higher strength number means higher minimum tensile strength, not universal superiority. The best electrode depends on base metal, joint design, welding position, required toughness, current type, and the applicable welding procedure.
What number tells the welding position?
The position digit is the number immediately before the final coating digit. A 1 means all positions, a 2 means flat and horizontal fillet positions, and a 3 means flat position only.
Does the last number show polarity?
The last number identifies a coating and current classification that is associated with particular polarity options. It is not a simple positive-or-negative switch for every rod. Always verify the product data sheet, especially for less common classifications.
Do the numbers show rod size?
No. Rod size is listed separately, usually in inches or millimeters. The same classification, such as E7018, can be manufactured in several diameters with different recommended amperage ranges.
Conclusion
The numbers on a stick-welding electrode identify its strength, welding position, coating, and general current characteristics. Once what do the numbers on arc welding rods mean is understood, codes such as E6010, E6013, and E7018 can be read quickly; the package instructions still provide the final guidance for diameter, amperage, polarity, storage, and approved use.
