What Do the Numbers Mean on a 7018 Welding Rod?

A apprentice welder once bought a crate of rods for a structural job, struck an arc, and watched the first bead cold-crack overnight — the rods were right, but nobody on the crew could read the code printed on the box. E7018 is more than four random characters; it is a complete specification for strength, welding position, coating chemistry, and hydrogen control, and once you can read it you can pick the correct rod for almost any carbon steel joint.

The Short Answer: Reading E7018 at a Glance

When it comes to the question of what the numbers mean on a 7018 welding rod, the answer is simple: it’s a coded classification that tells you exactly how the rod will perform before you strike an arc. Far more than a random string of characters, the code E7018 is a complete breakdown of tensile strength, welding position, coating type, and current compatibility. Learning to read it is one of the first skills that can prevent costly mistakes, especially on structural or code-restricted work.

Breaking Down E7018 One Character at a Time

The E7018 classification comes from the AWS A5.1 classification system maintained by the American Welding Society. This system is specifically for covered stick, or SMAW (Shielded Metal Arc Welding), electrodes. Each character of the first four digits has its own meaning:

• E – Stands for “Arc Welding Electrode”. This denotes that the rod is a consumable electrode that carries welding current and melts to become part of the weld metal. This differs from a non-consumable tungsten electrode, or filler rods such as ER70S-6, where the “R” specifies a solid rod rather than a covered electrode.
• 70 – Represents the minimum tensile strength of the deposited weld metal, measured in thousands of pounds per square inch. For E7018, this is a 70,000 psi (490 MPa) minimum. According to Lincoln Electric’s AWS classification data, this also comes with a minimum yield strength of 58,000 psi (400 MPa) for the all-weld-metal test specimen, not the base metal itself.
• 1 – Indicates all-position capability. An electrode with a ‘1’ can be used in the flat, horizontal, vertical, and overhead positions. However, this does not mean every diameter is equally practical out-of-position, a detail that will be expanded on later in this guide.
• 8 – Denotes a low-hydrogen, iron-powder rich coating. This coating type is designed for use with DCEP (Direct Current Electrode Positive), and for many qualified brands, can also be used on AC. It produces a smooth, stable arc with high deposition rates, making it one of the most versatile low-hydrogen rods available.

Quick Reference Table For E7018

Digit	Meaning	Application for E7018
E	Electrode (Covered, Consumable)	Stick electrode for SMAW.
70	70,000 psi Minimum Tensile Strength	Strong enough for most structural carbon steel work.
1	All-Position Welding	Usable flat, horizontal, vertical, and overhead.
8	Low-Hydrogen, Iron Powder Coating (DCEP/AC Qualified)	Quiet arc, high deposition, and hydrogen controlled welds.

A System That Scales With Strength

This coding isn’t exclusive to 7018. It is a scalable system used across the board for carbon steel electrodes. For example, E6010 is a 60,000 psi rod, E7014 is a 70,000 psi rod, and E8018 jumps up to an 80,000 psi class. The system even expands past four digits, with five-digit codes such as E10018 existing where the first three digits denote a 100,000 psi minimum tensile strength, as noted by the NRC’s welding training module.

For those just getting started in stick welding, this is designed with beginners and intermediate welders in mind. While this section covers the foundation, the rest of this

The Prefix E: Electrode, Rod, and Why the Letter Matters

Before you can work out the strength, welding position, or coating of a rod, you have to read the very first character of the code. On a 7018 stick electrode, that character is a single letter: E. It looks like a minor detail, but it is doing more work than any digit that follows it, because it tells you what kind of product you are holding, which process it belongs to, and whether it is meant to carry welding current at all.

What the E Actually Stands For

The E simply means electrode. Under the classification system published by the American Welding Society, a consumable arc welding electrode begins with E, and a plain carbon steel stick electrode such as E7018 falls under AWS A5.1, titled “Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding.” Every character in E7018 is dictated by that one specification, and the letter is the entry point.

What makes the designation meaningful is the unusual triple role a stick electrode plays. In stick welding, that one piece of metal is simultaneously:

• the filler metal that becomes the weld bead,
• the conductor that carries welding current from the machine to the arc, and
• the carrier of a flux coating that shields the puddle and cleans the base metal.

A bare TIG rod does none of the first job of carrying current, so it does not earn an E by itself. That distinction is the whole reason the letter exists.

Electrode, Rod, or Filler Wire? The Letter Tells You

Shop talk mixes up “rod,” “stick,” “wire,” and “electrode,” but the AWS prefixes are strict. Knowing the prefix keeps you from buying the wrong product for your machine, because the letter tells you whether the filler is designed to be part of the electrical circuit.

Prefix	Meaning	Typical example
E	Electrode: consumable and designed to carry arc current	E7018, E6011, E6013
ER	Electrode or filler rod: bare wire usable either way	ER70S-6 for MIG and TIG
F	Filler metal used as feed wire rather than a stick electrode	Submerged arc wire such as F7A6-EM12K
B / RB	Brazing filler metal or brazing rod	Classification under AWS A5.8

That comparison explains why ER70S-6 looks so different from E7018 even though both deposit a similar strength weld. The ER prefix says the wire can be used as a filler rod or as an electrode in a process like GMAW, and the S in the middle signals a silicon-killed, deoxidized bare wire. An E, by contrast, commits the product to arc electrode duty, where the covering and the current path are built into the design.

Why the Letter Matters at the Machine

The E also sets your expectations before you strike an arc. A covered electrode has a flux sheath that must survive being dragged, dipped, and restarted, so its manufacturer specifies the current type and polarity it tolerates, whether it runs on AC, DC straight, or DC reverse, and how dry the covering has to be kept. None of that applies to bare ER wire. In short, the first letter is your signal that you are dealing with a coated, current-carrying consumable that needs the right machine settings, the right electrode holder, and sensible storage.

Everything after the E narrows the picture down: how strong the weld metal is, which positions you may weld in, what the covering is made of, and what polarity the rod prefers. Those details are encoded in the four digits and the trailing suffix. But if you misread the first letter, the rest of the number is irrelevant, because you may be holding a filler wire for a different process entirely.

Once the E is settled, the digits take over, and that is where the actual numbers start to tell you something about what the rod can do.

The 70 Explained: Tensile Strength, Yield, and What 70,000 PSI Really Means

When looking at an E7018 rod, the “70” is the number that draws the most attention. After all, 70,000 psi sounds like an impressive rating, but it’s important to understand exactly what that number is referring to.

The short answer: it is a minimum tensile strength for the weld metal you deposit, set by the American Welding Society’s specification for carbon steel covered electrodes, AWS A5.1. In practical terms, one square inch of sound 7018 weld metal should survive roughly 70,000 pounds of pulling force, about 480 megapascals, before it fractures.

Tensile Strength: What the Test Actually Measures

Tensile strength is the stress a material withstands up to fracture (see how it is defined). To produce the number, a lab welds a standard groove joint under the procedure in AWS A5.1, machines a tensile coupon out of that weld, and pulls it apart in a testing machine. The peak load is divided by the cross-sectional area of the specimen, which gives the ultimate tensile strength.

So 70,000 psi describes a tested coupon, not a marketing claim: a bar with a one-inch square cross section would need about 70,000 pounds of force to snap it. The figure matters because most structural steels are weaker. Common A36 structural steel is specified around 58,000 psi tensile, so a properly fused 7018 welding rod deposit is actually stronger than the plate it joins.

Yield Strength: Where Permanent Deformation Starts

Tensile strength is the last stop before breakage; yield strength is where trouble begins. Yield is the stress at which metal stops springing back and starts deforming permanently (yield defined). For E7018 electrodes, minimum yield generally lands near 57,000 psi, roughly 390 MPa, or about 80 percent of the tensile figure.

Yield is often the more useful number in design and inspection. A beam loaded past yield is permanently distorted even though it has not snapped, while tensile strength only governs outright fracture. Welding codes and engineering specifications call out both, and compliant electrodes ship with a certificate of compliance listing the tested values.

Classification	Minimum tensile	Typical job
E6010	60,000 psi (410 MPa)	Deep-penetration root passes
E6011	60,000 psi (410 MPa)	AC all-position repair
E7018	70,000 psi (480 MPa)	Low-hydrogen structural welding

The Requirements That Aren’t Printed on the Can

Strength alone does not qualify a rod. AWS A5.1 also demands ductility: E7018 weld metal must show roughly 22 percent elongation in a two-inch gauge length and pass guided bend tests without cracking. A weld that hits 70,000 psi but splits on a bend test is rejected. That combination of high tensile strength with real ductility is why 7018 is the default for structural work instead of a harder, more brittle filler.

What 70,000 PSI Does Not Mean

• It is not the strength of the rod in your hand. The core wire is mild steel; the rating describes the deposited metal after the flux has done its work.
• It is not the strength of the finished joint. Fit-up, penetration, joint design, heat input, travel speed, and preheat decide whether the weld delivers rated properties.
• It does not change with diameter. A 1/8-inch and a 5/32-inch 7018 both carry the same “70” because the classification describes deposited weld metal, not rod size.
• It is not a pass on technique. Sloppy beads, poor fusion, or out-of-position welding performed against the rod’s listed positions can fall short of lab values.

The bottom line: the “70” sets a floor for tensile performance of the completed weld, with a yield figure near 57,000 psi and ductility requirements attached. Read it as a guaranteed minimum for correctly deposited metal, not as a promise about your finished joint, and it becomes one of the most useful numbers on the package.

The Third Digit 1: All-Position Welding and the Position Codes 1, 2, and 4

The third character in E7018 answers a very practical question: which way up can you actually weld with this rod? It is the position qualification, and on carbon steel stick electrodes it is almost always a 1, a 2, or a 4. Each number is a shorthand for a set of welding positions defined by the AWS A5.1 specification, and reading it correctly is the difference between buying a rod that works overhead and buying one that only works on a bench.

Position Codes at a Glance

Third digit	Positions the rod is qualified for
1	Flat, horizontal, vertical up and overhead (all positions)
2	Flat and horizontal only
4	Flat, horizontal, vertical down and overhead

These are the three codes you will meet most often, and they are exactly how Lincoln Electric’s AWS classification reference lays them out. So a 7018 is an all-position electrode, a 7024 is a position-4 electrode, and a 7028 is a position-2 electrode. That single digit also hints at the coating chemistry, because the positions a rod can handle are a direct consequence of how fast the arc digs, how fluid the puddle gets, and how the slag behaves. A coating that freezes the puddle quickly can be pointed in almost any direction; a coating loaded with iron powder builds a wide, fluid pool that needs gravity working with it rather than against it.

What “All Position” Actually Means (and Doesn’t Mean)

A 1 in the third slot means the electrode is qualified for flat, horizontal, vertical-up and overhead welding when tested at the diameters covered by the classification. It does not promise that every diameter will be comfortable everywhere. Look at the Pinnacle Alloys E7018 datasheet: the typical parameters table lists 3/16 in E7018 as suitable for flat and horizontal positions, while the all-position notation applies to the smaller diameters. Run a fat 3/16 in rod overhead or vertical and you will get a sagging, slippery puddle regardless of what the box says. In practice, most welders keep 1/8 in and 5/32 in rods for out-of-position work and save the thicker diameters for bench fillets, where travel speed matters more than access.

There is a second caveat. Although 7018 is technically qualified for vertical welding, that means vertical up. Almost no one recommends 7018 for vertical-down work, because the heavy lime-type slag traps ahead of the arc and drags into the weld, causing lack of fusion. You can see this reflected in product listings: Lincoln’s 7018 AC datasheet lists the welding positions as “All, except vertical down.” Vertical-down work is where fast-freeze rods like 6010 belong, since their thin coating lets the arc punch through and the puddle set almost instantly behind it.

Why the Codes Differ: 7024 and 7028

Compare the 7018 with its neighbours and the pattern is easy to spot:

• E7018 (position 1): low-hydrogen lime coating, medium penetration and a controllable puddle. The only rod in this group at home on a root pass, overhead or vertical up.
• E7024 (position 4): heavy iron-powder coating with high deposition and fast travel speeds. It shines on long butt welds and horizontal fillets on plate, where you can lay a wide bead and let the arc do the work.
• E7028 (position 2): the iron-powder cousin of the 7018, flat and horizontal only, built for high-deposition cover passes where a plain 7018 would crawl.

Practically, the third digit is a shortcut for matching a rod to the joint in front of you. If the work can be turned so the weld stays flat, a position-2 rod will deposit metal faster and with less fuss. If you are welding a pipe, a structural column or anything you cannot flip over, the 1 in E7018 is the reason that rod belongs on your list. Position codes say nothing about hydrogen, penetration or amperage; the strength digits and the final coating digit cover that. What they do tell you is simple: whether gravity will be helping or fighting the weld.

The Fourth Digit 8: Low-Hydrogen Iron-Powder Coating and Current Type

The last digit of an E7018 tells you about the coating and the recommended current. For the 7018 family that digit is 8: a low-hydrogen, iron-powder-rich mineral coating designed primarily for DCEP (Direct Current Electrode Positive), with many qualified products also rated for AC.

According to the AWS classification system, that coating is what gives E7018 its signature traits: a quiet arc, very low spatter, smooth fine ripples, medium penetration, and high deposition efficiency. All of them tie back to the iron powder blended into the low-hydrogen mineral flux.

Why Iron Powder Matters for Deposition Rate

The most visible benefit of iron powder is how much metal you can lay down per hour. Instead of relying solely on the core wire becoming weld metal, the coating itself melts and contributes filler to the puddle. That is where the deposition boost comes from.

On Pinnacle Alloys E7018 data, a 1/8″ rod running around 100 A shows a typical deposition rate of 2.6 lb/hr across its 90–130 A range. Compared with non-iron-powder electrodes, that added filler means fewer passes on larger joints and less rod consumed for the same volume of weld metal. It is a big reason E7018 is the default for structural fill and cap work, where speed, appearance, and hydrogen control all matter at once.

Comparing the Common Coating Digits

Each coating digit on carbon steel SMAW electrodes trades off penetration, positionability, current type, and hydrogen control to fit a specific job.

Digit	Coating Type	Common Example	Polarity	Key Traits
0	High-cellulose sodium	E6010	Primarily DCEP	Deep, digging arc for open roots and dirty steel. As NRC training materials note, this coating is very aggressive.
1	Cellulosic potassium	E6011	AC or DCEP	Similar penetration to E6010, but easier to run on older AC machines.
2	Rutile titania	E6013	AC or DCEP	Soft, stable arc with minimal spatter. Forgiving, but higher hydrogen than low-hydrogen rods.
3	Iron oxide	Variants of E7024	AC or DCEP	Fast, heavy deposition for flat and horizontal work, often paired with drag techniques.
4	Iron powder titania	E7014	AC or DCEP	Forgiving and easy to run with high deposition, but not a designated low-hydrogen rod.
8	Low-hydrogen iron powder	E7018	DCEP (AC if qualified)	Quiet arc, low spatter, medium penetration, and high deposition from its iron powder content.

The Trade-Off: Control Over Penetration

All that iron powder and hydrogen control comes with a trade. E7018 will not dig like an E6010. Its medium penetration suits most structural joints, but it is not the rod for burning through heavy rust and mill scale, or for a keyhole root on a wide open bevel without proper prep. On those joints, crews switch to a cellulose rod’s digging arc and come back to the 8 for fill and cap.

The goal of E7018 isn’t maximum penetration, it’s maximum soundness. The low-hydrogen coating limits the diffusible hydrogen reaching the weld, which is why it is far more resistant to hydrogen-induced cracking than the high-cellulose options.

Arc Characteristics You Can Expect

In practice, the 8 coating is what makes E7018 easy to stack beads with: a quiet, stable arc, very little spatter, and a puddle that feels slightly more viscous than a rutile electrode. Fillet welds come out slightly convex with smooth, fine ripples, the telltale sign of a properly running 7018. To keep those traits, the arc has to stay short. Long arcing wastes the coating’s benefits and raises the odds of porosity.

Putting It All Together

The fourth digit is why E7018 earns its spot as a code-driven rod: a low-hydrogen mineral base blended with iron powder, built for soundness over brute force. On DCEP you get medium penetration, a clean arc, high deposition, and crack resistance. Qualified AC-rated products add machine versatility without giving up the low-hydrogen benefits.

Compared with the rest of the coating family, the trade is simple. You give up some of the digging power of an E6010 or E6011 in exchange for better bead appearance, faster fill work, and the confidence that comes with hydrogen control. Wherever cold cracking is a concern, that swap is more than worth it.

Beyond Four Digits: Reading Suffixes Like H4, H8, R, -1, A1, and M

Once you understand the base E7018 code, the letters and numbers that follow are where most welders get lost. These suffixes aren’t just extra markings, they tell you exactly how much diffusible hydrogen is allowed, how well the rod resists moisture, its low-temperature toughness, and sometimes, which low-alloy steel it’s meant to weld.

Diffusible Hydrogen: The H Designators

The most important suffixes for code work are the hydrogen designators: H4, H5, H8, H10, and H16. These numbers represent the maximum allowable diffusible hydrogen in milliliters per 100 grams of deposited weld metal, tested in accordance with AWS A4.3. According to Böhler’s guide, H4 is defined as less than 4 mL per 100 g of weld metal. The lower the number, the stricter the hydrogen limit.

These limits are a ceiling, not a guarantee. For example, Lincoln IRONARC 7018 MR is classified E7018 H4R, carrying a maximum of 4 mL/100 g with typical results between 1–3 mL/100 g. On the other hand, Lincoln 7018 AC is classified E7018 H8, allowing up to 8.0 mL/100 g with typical results of 2–4 mL/100 g. Both can be very clean, however, the H4R is held to a much tighter requirement.

Moisture Resistance: The “R” Suffix

Next to an H designator, you’ll often see R. This denotes a moisture-resistant coating, meaning the flux has been formulated and treated to reduce moisture absorption. As Böhler states, R stands for reduced moisture absorption. This doesn’t mean the rod is waterproof, it simply buys you more time before it becomes vulnerable to dampness. Even with an R coating, proper storage is still mandatory for any low-hydrogen rod.

Low-Temperature Toughness: The “-1” Suffix

If you see a -1 after the position/coating digits, such as E7018-1, this indicates improved low-temperature impact toughness. These rods typically keep manganese at the high end of its allowed range to achieve this. To prove it, they’re tested to meet optional low-temperature impact requirements. Pinnacle Alloys notes their E7018-1 has typical diffusible hydrogen of just 2.1 mL/100 g by gas chromatography, showing that high toughness and ultra-low hydrogen can go hand in hand.

Alloy Designators: A1, B2, B3, C1, C2, C3, and M

When stepping away from plain carbon steel and into low-alloy steels, you’ll see chemistry suffixes from AWS A5.5 or AWS A5.1. For those looking into alloy steel welding electrodes, these are essential. Examples include A1 (carbon-molybdenum), B2/B3 (chromium-molybdenum), C1/C2/C3 (nickel steels), and M, which denotes a military specification variant under MIL-E-22200. These tell the welder the deposited weld metal is alloyed to match or complement specific low-alloy base metals.

Putting It All Together With Real Examples

The suffixes can be combined, and this is exactly what you’ll find on code boxes. Here’s a quick breakdown of some real world classifications:

Classification	What It Means In Practice
E7018-1 H4R	70 ksi low-hydrogen rod, improved low-temperature toughness (-1), max 4 mL/100 g hydrogen, and moisture resistant coating.
E7018-A1 H4R	Same low hydrogen and moisture resistance, but with A1 carbon-molybdenum alloy for welding A335 P1 or similar low-alloy steels.
E8018-C3 H4R	80 ksi, nickel-alloyed (C3) low-hydrogen rod for higher strength, low-alloy applications with strict hydrogen control.
E71T-8 H8	A flux-cored example. Notice the H8 carries over, showing hydrogen designators aren’t exclusive to stick electrodes.

One commercial example worth noting is ESAB’s Atom Arc 7018, which carries E7018 H4R with approvals from ABS, DNV, LR, and MIL-E-22200/1. These third-party approvals are only obtainable when the rod consistently meets its H4R qualifications.

Why the Hydrogen Code Matters: Cracking, Codes, and Rod Storage

The “8” on E7018 tells you the flux is low-hydrogen, and the optional H designators tell you exactly how low. That distinction is not marketing. It is the difference between a weld that passes inspection at 8 a.m. and a weld that has a hairline crack under the bead by lunchtime. Low-hydrogen electrodes exist because hydrogen, in the wrong place at the wrong time, quietly breaks steel apart after the arc is gone (Lincoln Electric’s guide to low-hydrogen SMAW electrodes explains why this class of coating became the default for structural work).

Hydrogen-Induced Cracking: The Crack You Do Not See Form

Hydrogen-induced cracking is also called cold cracking or delayed cracking, and it happens in three overlapping conditions:

– Diffusible hydrogen is present. Water in the flux, oil, rust, paint, or grease on the plate all dissociate in the arc and release hydrogen, which soaks into the cooling metal.
– A susceptible microstructure forms. The heat-affected zone (HAZ) cools into hard, brittle regions, especially in thicker or higher-carbon steel.
– Residual stress pulls at it. Shrinkage of a restrained joint provides the tension.

Give all three to the same spot and a crack can nucleate hours after you racked your stinger. It usually shows up as an underbead crack in the HAZ or a toe crack at the weld edge, invisible until magnetic particle or ultrasonic inspection finds it. This delayed behavior is exactly why a repair weld that “looked fine” overnight can fail later.

The three controls welders and codes use against it are straightforward:

1. Low-hydrogen consumable — E7018’s lime-based coating, plus H4/H8 limits where specified.
2. Heat input and preheat — slow the cooling rate so hard structures never form.
3. Stress management — sequence, peening where permitted, and avoiding extreme restraint.

Storage and Reconditioning: Where Rods Go Wrong

A fresh E7018 starts with a low hydrogen pickup, then gains it from the atmosphere the moment the carton is opened. Flux coatings are hygroscopic, so storage is an active task, not a shelf decision. The Hobart Brothers storage chart gives practical numbers:

Electrode type	Holding temperature	Reconditioning
E7018 / E8018 / E9018 (low hydrogen)	250–300°F holding oven	500–800°F for 1–2 hours
Cellulosic E6010 / E6011	Room temperature, dry	Not recommended; never above 130°F

Those two rows explain the most common oven mistake in small shops: baking 6010. The cellulose in a cellulosic coating is what gives E6010 its deep, digging arc, and heat destroys it. Bake it and you have ruined the rod’s penetration characteristics, not dried it.

Manufacturers vary slightly on the details. Pinnacle Alloys recommends holding opened E7018 cartons at 250–300°F, and for rods exposed long-term, ramping slowly to 600°F and baking one hour (Pinnacle E7018 datasheet). The Fabricator reports that most low-hydrogen rods need roughly 500–700°F for effective reconditioning (electrode storage myths and rod oven temperatures).

Between oven sessions, treat rods like food: keep them in sealed containers, rod caddies, or a portable quiver oven, and bake only what you will use that shift. The visible symptom of skipping this is porosity — clusters of pinholes and blowholes from moisture in the flux. Underbead cracking is the invisible one, and it is far more expensive.

Low-alloy rods such as E7018-A1 and E8018-C3 carry the same H designators and the same storage discipline (Alloy Steel Welding Electrodes: Selection, Use & Safety). If the box says H4, treat the rod as a precision consumable: dry, warm, capped, and used within the exposure window. That habit, more than any dial setting, is what keeps a 7018 weld out of the repair column.

7018 vs the Other Common Numbers: 6010, 6011, 6013, 7014, 7024

A rod code tells you what one electrode can do. Knowing which rod the job actually calls for is the other half of the skill, because E7018 is not a universal answer. A 7018 that runs like glass on clean 3/8 in plate will fight you on a rusty bracket, while a 6010 that chews through an open root will splatter on thin sheet. Here is how the six carbon-steel stick electrodes you will really meet compare.

Quick Comparison: Six Electrodes Side by Side

Electrode	Tensile	Coating type	Current	Penetration	Storage
E6010	60 ksi	High cellulose sodium	DCEP only	Deep, forceful	Dry only
E6011	60 ksi	Cellulosic potassium	AC or DC	Deep, forceful	Dry only
E6013	60 ksi	Rutile titania	AC or DC	Shallow, soft	Dry only
E7014	70 ksi	Iron powder titania	AC or DC	Medium	Dry only
E7024	70 ksi	High iron powder titania	AC or DC	Medium; flat/horizontal only	Dry only
E7018	70 ksi	Low-hydrogen iron powder	DCEP (AC when qualified)	Medium	Rod oven or sealed container

The Cellulosic Family: E6010 and E6011

E6010 is the classic DCEP root rod. Its cellulose-sodium coating burns with a violent, digging arc that punches through mill scale, light rust and contamination, and it leaves a thin, easily cleaned slag. A typical 1/8 in E6010 runs at about 75–135 A on DCEP. It is the rod of choice for open-root pipe, where you need to see the keyhole and drive the puddle into the root face.

E6011 is the same idea adapted for AC. The potassium in the coating stabilizes the arc when the current alternates, so E6011 runs on AC, DCEP or DCEN machines, which makes it the universal repair rod. Lincoln Electric’s classification guide notes that cellulosic rods burn through rust, paint, oil and galvanized coatings that would wreck a low-hydrogen arc. Keep both types dry, but never rebake them in a rod oven.

The Easy Rods: E6013, E7014, and E7024

E6013 is the soft-arc hobby rod. It starts easily on AC or DC, runs quiet with minimal spatter, and penetrates gently enough for thin sheet and body panels. The trade-off is shallow fusion and a 60 ksi strength class, so it is not a structural choice.

E7014 steps up to 70 ksi and adds iron powder to a titania coating, which boosts deposition and lets you run longer arcs and faster travel. It behaves similarly to E7018 but without the strict storage requirements, making it a smart production rod for clean steel where rod ovens are impractical. E7024 takes the iron powder concept further: a thick coating, very high deposition rates, and a position rating of 4, meaning flat and horizontal only. It is the go-to for long, fat fillets on heavy plate. For more on how position ratings limit rod choice, see our all position welding rod guide.

The Code Rod: E7018

E7018 is the only low-hydrogen electrode in this group, and that is the whole point. It runs a quiet arc with low spatter and medium penetration, producing weld metal with the toughness and hydrogen control that structural codes demand. ESAB’s Atom Arc 7018 data describes exactly this profile, and the Pinnacle Alloys datasheet lists a 1/8 in range of roughly 90–130 A, with Lincoln Electric’s AC-tolerant variant rated around 100–140 A on DC+ and 105–150 A on AC. The price is storage discipline: opened cartons belong in a rod oven or sealed container, unlike every other rod here.

The Classic Two-Rod System

Most field work uses two rods, not one. The standard practice in pressure piping is a 6010 (or 6011 on AC machines) root pass for penetration and keyhole control, followed by 7018 fill and cap passes for strength, toughness and appearance. Structural welding under AWS D1.1 generally requires low-hydrogen electrodes for the production passes, so 7018 fills and caps dominate; the cellulosic rod is there to solve the root. That is one reason stick still holds its ground on jobsites, as we cover in the advantages of stick welding.

The Real Trade-Offs

Every choice here is a balance. Penetration favors 6010 and 6011; deposition favors 7024 and 7014; appearance and low spatter favor 7018 and 6013. Hydrogen control favors 7018 alone, and that control costs money, in rod price and in the oven, propane and sealed containers that protect it. Cleanup differs too: cellulosics leave a thin slag that chips easily but throw more spatter, while 7018 leaves a heavier shell that lifts in strips once the bead cools. Commodity 6013 and 7014 are cheapest per pound; low-hydrogen 7018 is priced for code work.

What a Hobbyist With a 180-Amp Machine Should Keep on Hand

A 180 A machine comfortably runs 1/8 in rods across the board and can push 5/32 in 7018 in flat positions. The practical starter kit is a pack of 1/8 in E6013 for thin material and practice, a pack of 1/8 in E7014 for general fabrication without oven worries, and a pack of 1/8 in E7018 for anything structural. Add 1/8 in E6010 for dirty metal or a root pass, and you can cover nearly anything that shows up on a home shop floor.

Settings and Technique: Getting the Most Out of Your 7018

Reading the classification tells you what the rod can do. Getting a sound 7018 weld out of it depends on settings and hand skills the wrapper never prints. Once you understand what the “8” coating actually is, the technique mostly explains itself.

Amperage by Diameter: Where to Start

Amperage is the first variable, and it scales with rod diameter and material thickness. These are the commonly cited starting windows:

Diameter	Typical Range	Best Suited For
3/32 in (2.5 mm)	70–110 A	Thin material, out-of-position, root passes
1/8 in (3.2 mm)	90–160 A	The do-everything shop size
5/32 in (4.0 mm)	120–220 A	Flat and horizontal fill and cap

Manufacturer data backs this up. ESAB’s Atom Arc 7018 lists direct-current electrode positive ranges of 70–110 A, 90–160 A, and 120–220 A for those three diameters, and reports deposition efficiency of roughly 69% at 3.2 mm with a deposition rate near 0.92 kg/h (about 2.0 lb/h) at 90% of maximum current. That high efficiency comes straight from the iron powder in the covering, which melts into the puddle rather than burning away as slag.

AC ranges run slightly higher than DC on the same rod because effective output is lower on most machines. Lincoln Electric’s operating data for E7018 AC lists 75–120 A at 3/32 in, 105–150 A at 1/8 in, and 130–200 A at 5/32 in, with DC+ ranges of roughly 70–115 A, 100–140 A, and 120–185 A. When a box says “E7018 AC,” the rod is specifically qualified and tested on alternating current; a standard E7018 is intended for direct current electrode positive unless the manufacturer says otherwise.

Polarity: Why DCEP Is the Default

Most 7018 rods perform best on DCEP (DC+, electrode positive). The deeper, more stable arc and cleaner transfer on DC are part of why 7018 is the workhorse of structural welding. Reach for AC in only two situations: when your rod is explicitly AC-qualified, or when you are welding magnetized or position-critical work where arc blow on DC becomes unmanageable. If you are curious how stick compares to other processes, our advantages of stick welding guide covers where SMAW still beats everything else.

Arc Length, Angle, and Travel

Here is the single most important technique rule for 7018: keep the arc short. Pinnacle Alloys’ technical data advises a short arc at all times, because the mineral-based low-hydrogen covering is not self-stabilizing the way a cellulose or rutile rod is. Hold the electrode roughly one diameter or less from the puddle and you get the quiet, buttery arc 7018 is famous for. Stretch it out and the arc wanders, the covering cracks back prematurely, and you introduce both spatter and hydrogen from the atmosphere.

Travel angle follows the same logic. Use a modest drag angle of about 10 to 15 degrees and let the puddle lead. The iron powder content means 7018 deposits more metal per amp than a 6010 or 6013, so slow your travel slightly. A properly fed bead looks almost glassy, with consistent ripples and a slag cover that lifts cleanly off the edges.

Vertical-Up and Out-of-Position Work

Out of position, drop amperage by roughly 10 to 15% and step down in rod size: 3/32 in or 1/8 in handles vertical-up and overhead far better than 5/32 in. On vertical-up, a slight weave or tight circles tie into both walls and control the shelf of puddle that wants to run ahead of you. Vertical-down is generally not recommended, because the heavy mineral covering can’t keep up with fast travel and you will trap slag. For more on which rods suit which positions, see our all position welding rod guide.

A few practical details round out the technique:

• Tacks: use the same rod and polarity you will use for the weld. Tack with a cold rod and you may crack the tack before the real pass goes down.
• Restarts: strike on the crater or a slight lead-in, then come back onto the solidified bead. Trim the end before striking rather than arcing on exposed core wire.
• Long arcing: never drag the rod across the plate like a match. It bakes moisture out of the covering away from the puddle, wrecks the flux chemistry, and is a leading cause of porosity and hard starts.
• Slag removal: chip and wire-brush between passes. If slag welds over stubbornly, the real problem is usually amperage, not the chipping hammer.

Common Mistakes, Troubleshooting, and Safety with 7018

Even experienced welders ruin good E7018 rods and good joints, usually through habits that would never hurt a 6013 but destroy a low-hydrogen electrode. The classification itself warns you: the “8” in E7018 promises a quiet, low-spatter, low-hydrogen arc only if the coating and your technique cooperate. Here is what goes wrong, why, and how to fix it.

Common Mistakes That Ruin 7018 Welds

• Storing rods in a damp bucket or open carton. The calcium carbonate coating actively absorbs moisture from the air. Rods left overnight in a humid shop can pick up enough hydrogen to cause porosity or, worse, invisible underbead cracking. Welding with those “cold” rods the next morning is not welding with the rods you bought, no matter what the box says.
• Running too long an arc. Low-hydrogen electrodes require a short arc to maintain shielding and avoid hydrogen pickup from the atmosphere, as Lincoln Electric’s low-hydrogen SMAW guidance emphasizes. Stretching the arc invites arc blow, porosity, and a coarse, wandering bead.
• Welding too cold. Undersized amperage shows up as sluggish slag, cold lap, slag inclusions, and lack of fusion, especially at the toes.
• Using flat drag technique everywhere. 7018 is a drag rod in flat and horizontal, but vertical-up work demands a different manipulation with slightly faster travel and a tight arc to keep the puddle from sagging.
• Welding rusty or greasy plate. Contaminants break down shielding and add hydrogen. Clean at least an inch either side of the joint.
• Skipping preheat on thick or restrained joints. Hydrogen cracking needs three ingredients: hydrogen, stress, and a hard microstructure. On heavy, cold, or highly restrained steel, preheat removes one of them.
• Confusing E7018 with “E7018 AC.” A rod marketed as E7018 AC is a separately qualified product with a different coating. Do not assume a standard DCEP 7018 will run smoothly on your machine’s AC setting.
• Baking cellulosic rods. Never put 6010 or 6011 rods in a rod oven. The cellulose burns, and the electrode is ruined.

Troubleshooting by Symptom

Symptom	Likely Cause	Fix
Porosity and pinholes	Damp flux, long arc, contaminated joint	Rebake at 500–800°F for 1–2 hours, shorten the arc, clean the plate
Heavy spatter	Too much current, wrong polarity, arc too long	Drop amperage 5–10 A, switch to DCEP, tighten the arc
Difficult arc starts	Cold rods, cracked coating, AC on a DCEP rod	Use dry rods, check the stick, run DCEP or an AC-qualified rod
Slag trapped in the weld	Amperage too low, travel too fast, no cleaning between passes	Increase amperage, slow down, brush and grind each pass
Underbead or toe cracking	Excess hydrogen, hard HAZ, high restraint	Dry rods, preheat, verify an H4 or H8 rod for code work
Flat, washed-out bead	Amperage too high	Reduce current; a 7018 bead should be a smooth, slightly convex ripple

Rebaking and Rod Oven Discipline

Hobart’s electrode storage guidance recommends holding open cartons in a low-temperature holding oven around 250–300°F and rebaking exposed low-hydrogen rods at 500–800°F for one to two hours, with Pinnacle Alloys advising gradual temperature ramping to avoid shocking the coating. A household oven that cannot hold a stable, verified temperature is not a rod oven. And keep one rule absolute, per The Fabricator’s coverage of electrode storage myths: cellulose-coated 6010 and 6011 rods are never baked.

Safety: The Part Nobody Reads Until It Matters

Rebaked rods come out of the oven at several hundred degrees. Let them cool in a controlled area, handle them with gloves and tongs, and keep them away from solvent rags and packaging. Welding arcs emit intense ultraviolet and infrared radiation, so a properly shaded helmet, fire-resistant clothing, and dry gloves are non-negotiable. Ventilation matters too: stick welding generates manganese and other fumes, and OSHA’s welding, cutting, and brazing guidance covers eye protection, ventilation, and fire control as core requirements for any shop. Use local exhaust where space is confined, keep a charged extinguisher within reach, and never weld where a failed oven’s exhaust is still pooling.

Short Note: Treat your rod oven as safety equipment, not storage furniture. Ovens not rated for the temperature can overheat coatings, damage elements, or start fires.

Respect the hydrogen the code warns you about, keep your amperage honest, and an E7018 rod will hand you the same tough, code-qualifying weld today and a year from now. For how these designators extend beyond carbon steel, our guide to alloy steel welding electrodes covers the A5.5 system in the same numbering logic.

Frequently Asked Questions

What does the 70 mean on a 7018 welding rod?

It means the weld deposit has a minimum tensile strength of 70,000 psi (about 490 MPa), tested as all-weld-metal per AWS A5.1. Actual test results from quality 7018 electrodes often run 80,000 to 85,000 psi.

What does the 1 in the middle of E7018 mean?

The third digit is the position code. A 1 means the electrode can be used in all positions: flat, horizontal, vertical up, and overhead. A 2 means flat and horizontal only, and 4 adds vertical down.

What does the 8 in E7018 stand for?

The fourth digit describes coating type and current. An 8 indicates a low-hydrogen, iron-powder mineral coating that runs on DCEP (and on AC when the specific product is qualified for it), giving a smooth arc with low spatter.

What do H4 and H8 mean after E7018?

They are diffusible hydrogen limits in milliliters per 100 grams of deposited weld metal: H4 is 4 mL/100 g maximum and H8 is 8 mL/100 g maximum, measured per AWS A4.3. Lower numbers mean drier, more crack-resistant deposits.

What does the R suffix mean on E7018 H4R?

R stands for a moisture-resistant coating that slows moisture pickup during storage and handling. It does not replace proper storage, but it gives extra margin before rebaking is required.

Does E7018 need to be kept in a heated oven?

For code and structural work, yes: hold opened low-hydrogen rods at 250–300°F and rebake exposed rods at 500–800°F for 1–2 hours per manufacturer guidance. Rods stored at room temperature for casual non-code work will still often weld, but they can pick up moisture and cause porosity.

Can I run a 7018 rod on an AC stick welder?

Standard E7018 prefers DC electrode positive, but products such as E7018 H8 AC are formulated for stable AC operation. Always check the data sheet; running a non-AC-rated 7018 on AC can give erratic arcs and poor starts.

What is the difference between E7018 and E6010?

E6010 is a 60 ksi cellulose electrode with a digging arc for roots and dirty steel, while E7018 is a 70 ksi low-hydrogen electrode for strong, tough, code-quality fill and cap passes. Many jobs use a 6010 root with 7018 fill.

What amperage should I use for a 1/8 inch 7018 rod?

Typical ranges are 90–130 A on DCEP for general products and about 100–150 A for AC-qualified versions, depending on manufacturer. Reduce amperage roughly 15% for out-of-position welding.

What does E7018-1 mean?

The -1 suffix indicates an optional supplementary test for improved low-temperature impact toughness, with the manganese content held at the high end of the AWS range. It is chosen for service where notch toughness at low temperature matters.