Understanding AWS Classification of Carbon Steel Welding Electrodes: E6010, E6013, and E7018

In structural steel fabrication, pressure vessel manufacturing, and industrial maintenance, selecting the correct welding consumable is a critical decision. Using the wrong welding rod can result in poor weld penetration, excessive spatter, slag inclusions, or weld cracking under load.

To standardize selection, the American Welding Society (AWS) established the classification system for carbon steel electrodes (AWS A5.1).

This technical guide decodes the AWS classification system, compares the three most widely used industrial electrodes—E6010, E6013, and E7018—and explains how their chemical coatings dictate their performance.

---

1. Decoding the AWS Classification System

The alphanumeric code stamped on every carbon steel welding rod contains specific engineering data regarding its strength, welding position, and coating chemistry.

The First Digit: “E”

Indicates an arc welding Electrode.

The Next Two Digits: Tensile Strength

Represents the minimum tensile strength of the deposited weld metal in thousands of pounds per square inch (ksi):

• 60: Minimum tensile strength of 60,000 psi (414 MPa).
• 70: Minimum tensile strength of 70,000 psi (482 MPa).

The Third Digit: Welding Position

Dictates the positions in which the electrode can be successfully operated:

• 1: All positions (Flat, Horizontal, Vertical, Overhead).
• 2: Flat and Horizontal fillet welds only.
• 4: Vertical-down, Flat, Horizontal, and Overhead.

The Fourth Digit: Coating and Current

Indicates the chemical composition of the flux coating, the penetration depth, and the electrical current compatibility (AC, DCEP, or DCEN).

---

2. Coating Chemistry: Cellulose vs. Rutile vs. Low-Hydrogen

The flux coating on a welding rod performs several functions: it stabilizes the arc, generates a shielding gas to protect the weld pool from atmospheric oxygen and nitrogen, and forms a protective slag over the cooling weld bead.

---

3. Engineering Performance Matrix

The following matrix compares the mechanical and operating characteristics of these three critical electrodes:

Parameter	E6010	E6013	E7018
Tensile Strength	62,000 psi (427 MPa)	67,000 psi (462 MPa)	72,000 psi (496 MPa)
Yield Strength	50,000 psi (345 MPa)	58,000 psi (400 MPa)	60,000 psi (414 MPa)
Arc Force & Penetration	Violent / Deep Penetration	Soft / Light-to-Medium	Medium / Medium-to-Deep
Slag Characteristic	Very thin, easily cleaned	Heavy, self-peeling	Medium, glassy, requires chipping
Current Compatibility	DCEP only	AC, DCEN, DCEP	DCEP, AC
Weld Quality (X-Ray)	Good	Fair	Outstanding (X-ray quality)

---

4. Selection Guidelines for B2B Procurement and Engineering

When specifying welding consumables for a project, consider the following application rules:

Specifying E6010: The Pipe Welder’s Rod

E6010 is the industry standard for the root pass of open-butt pipe welds (such as oil and gas pipelines). Its aggressive arc forces the weld metal through the gap, creating a solid backside bead (high penetration). It is also highly tolerant of rust, oil, and paint.

Specifying E6013: The General Fabricator’s Rod

E6013 is optimized for thin sheet metal, light structural frames, and cosmetic welds. Because it has a very stable arc and low spatter, it is easy for welders to control. It is also highly effective when using small, portable AC welding machines.

Specifying E7018: The Structural Standard

E7018 is mandatory for all structural steel buildings, bridges, pressure vessels, and heavy machinery fabrications. The iron powder in the coating increases the deposition rate, while the low-hydrogen mineral base ensures the weld metal is free of microscopic cracks, making it capable of surviving high dynamic loads.

---

Conclusion: Partner with VOTNE for Certified Welding Consumables

Consistent weld quality requires consistent electrode manufacturing. At VOTNE, our carbon steel welding electrodes are manufactured using ultra-pure steel cores and precision-extruded flux coatings. Whether you need the deep penetration of E6010, the smooth operability of E6013, or the certified low-hydrogen performance of E7018, VOTNE consumables are batch-tested to exceed AWS standards.

Contact our sales and engineering team today to receive product data sheets, chemical mill certificates, or a B2B volume quotation.

• Email: sales@votne.com
• Technical Support: Fill out our Contact Form to consult with a B2B parts specialist.