7018 Welding Rod Meaning: What the Numbers Actually Mean

A welder opens a fresh box of 7018 rods on a structural job, and a journeyman asks what the numbers on the package actually mean — the room goes quiet, because most people can only guess at the ’70’. That four-digit code is not decoration; it is a complete specification for strength, position, flux chemistry and current, and once you can read it you can pick the right rod for any joint.

The Short Answer: What 7018 Welding Rod Meaning Really Is

A box of rods shows up on the bench and someone reads the label out loud: “seven-oh-eighteen.” Somebody nods, somebody guesses at the “70,” and nobody actually explains the rest. That scene plays out in nearly every shop and welding lab, and it matters more than it looks. Those four digits are a complete specification, and misreading them is how a beginner ends up running a rod that looks similar but behaves nothing like the one the job called for.

Here is the direct answer. 7018 is shorthand for the AWS classification E7018, a covered stick electrode used in shielded metal arc welding, better known as SMAW or simply stick welding. The leading “E” stands for electrode, which distinguishes it from an “ER” classification (electrode/rod) used for bare GMAW and GTAW filler wires. So when someone asks what 7018 “means,” they are really asking what the specification E7018 promises about the weld it deposits.

The Standard Behind the Code

That promise is not a marketing invention. It comes from AWS A5.1, Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding, the governing document for this family of electrodes. The current edition is AWS A5.1/A5.1M:2025, which replaced earlier revisions such as the widely referenced fourteenth edition, A5.1/A5.1M:2012.

The history is worth knowing because it explains why the code is trusted. According to AWS’s own foreword, the predecessor to A5.1 was issued in 1948 as ASTM A233-48T / AWS A5.1-48T, making it the first filler metal specification ever published. That is more than 70 years of accumulated testing, welding practice and inspection data sitting behind a number you can read off a cardboard box.

What Each Character Promises

You do not need the whole standard memorized to get real value out of the code. Each character carries one piece of the specification:

• E – the product is an electrode (a consumable that carries welding current).
• 70 – the deposited weld metal has a minimum tensile strength of 70,000 psi, roughly 480-490 MPa.
• 1 – the electrode is qualified for all positions: flat, horizontal, vertical and overhead.
• 8 – the covering type, penetration and current group. An “8” indicates a low-hydrogen (basic) covering with iron powder, medium penetration, usable on AC or DCEP.

Taken together, E7018 describes a low-hydrogen, iron-powder, all-position electrode that runs on AC or direct current electrode positive and delivers at least 70,000 psi of tensile strength. That is a great deal of information in five characters, and each part directly changes how the rod behaves in your hands.

Why This Matters on Your First Rod

This article is written for beginners, welding students, DIYers and apprentices who keep running into the same wall: everything in the rack looks like a metal stick with a coating. Rod choice is where hobby work starts behaving like real work. The wrong selection shows up later as porosity, lack of fusion, a cracked root, or a visual inspection reject that costs time and money. If you can read the classification, you can walk into any supply house and ask for what the drawing actually specifies instead of describing a color or a shelf position.

The classification also explains why stick welding refuses to disappear. If you are weighing processes, our Advantages of Stick Welding: Why SMAW Still Wins guide covers where this process still outperforms wire feeding, and our All Position Welding Rod Guide: Types, Uses & Tips shows how the position digit reshapes what you can do out of position.

From here, we will take the code apart digit by digit, then work through the suffixes, the metallurgy behind the “8,” machine settings, rod comparisons, storage rules and the real jobs where E7018 is required. The short version to carry with you: 7018 means a strong, all-position, low-hydrogen electrode certified to a standard older than most of the equipment in your shop.

Decoding the Digits: E, 70, 1 and 8 Explained

The AWS classification reads left to right, and each character answers a different question about the rod. Once you see the pattern, E7018 stops being a random number and becomes something you can reason about. Here is the whole code unpacked in one pass.

Character	What it tells you	What E7018 specifically means
E	The product type	A covered consumable electrode that carries welding current
70	Minimum tensile strength	70,000 psi (70 ksi) minimum on the deposited weld metal
1	Welding position capability	All positions: flat, horizontal, vertical and overhead
8	Covering type, penetration and current	Low-hydrogen (basic) covering with iron powder, medium penetration, AC or DCEP

The “E” — electrode, not filler wire

The leading letter tells you what the product is. An E is an electrode: a covered stick that carries current across the arc and becomes part of the weld. When you see ER, as in ER70S-6, you are looking at a filler rod that feeds into the puddle but does not carry the arc itself — the TIG or MIG torch does. Same digits, different animal. Since 7018 is always an E, you know instantly that it is a stick electrode for shielded metal arc welding, and that the flux covering on the outside is doing real work in the arc.

The “70” — strength in thousands of psi

The two digits after the letter are the minimum tensile strength of the deposited weld metal, expressed in thousands of pounds per square inch. E7018 therefore guarantees at least 70,000 psi tensile strength. The governing standard, AWS A5.1/A5.1M:2025, specifies 480 MPa (70 ksi) minimum tensile, 400 MPa (58 ksi) minimum yield and 22% minimum elongation for a plain E7018. The same specification also requires a Charpy V-notch impact value of 27 J (20 ft-lb) minimum at −29°C (−20°F) for a non-suffixed E7018, which is why structural inspectors care about the number rather than the brand on the box.

Read the rest of the family the same way: E6010 guarantees 60,000 psi, E8018-B2 guarantees 80,000 psi. If the strength figure rises above 70, you are almost always looking at a low-alloy or hardfacing rod rather than plain carbon steel.

The “1” — position

The third digit is the position qualifier. A 1 means the electrode is qualified for all four positions: flat, horizontal, vertical and overhead. A 2 would restrict it to flat work and horizontal fillets only, which is common on heavy, high-deposition rods that dump metal too fast to fight gravity. This is the digit that separates a rod you can climb a column with from one you can only run in a shop on the bench. For more on how that plays out in the field, see our all-position welding rod guide.

The “8” — the fourth digit table

The last digit is the most misunderstood, because it is not a strength or position number at all. It is a pointer into a table in AWS A5.1 that codes three things at once: the chemistry of the flux covering, how deeply the arc penetrates, and which currents the rod will run on. An 8 means a basic (low-hydrogen) covering loaded with iron powder, medium penetration, and the ability to run on AC or DCEP (reverse polarity). The manufacturer’s classification chart in Hobart’s AWS classification reference lays out the full set side by side.

That is why 7018 and 6013 weld so differently even when the digits before them look similar. The covering dictates arc action: cellulose rods dig, titania rods wash and smooth out, and the basic covering on a 7018 gives up some penetration in exchange for clean, tough, low-hydrogen weld metal. Digits 5, 6 and 7 are essentially unused in routine carbon steel work, so if you can read 0, 1, 2, 3, 4, 8 and 9, you can decode almost every stick electrode you will pull off the rack.

The Suffixes: What -1, H4, H8 and R Add to 7018

Pick up a box of 7018 and you may see more than four digits. The label might read E7018-1 H4R, E7018 H8, or E7018-1 H4. Those trailing characters are not marketing and they are not brand codes. They are optional supplemental designators defined in the same AWS A5.1 specification that governs the base classification, published as AWS A5.1/A5.1M:2025. A manufacturer only earns the right to print them by testing and documenting the extra requirement. Once you can read them, you know exactly what that rod was built to survive.

The “-1” Suffix: Toughness That Holds Up in the Cold

Plain E7018 must pass a Charpy V-notch impact test at −29°C (−20°F). Rods marked E7018-1 are held to a tougher standard: 27 J (20 ft-lb) at −46°C (−50°F). Same tensile strength, same all-position capability, but verified resistance to brittle fracture at far lower temperature. That matters on a January structural erection in Minnesota, on outdoor pressure piping, or anywhere a shock load hits a cold weld. The “-1” does not make the rod stronger; it makes the weld metal more predictable when the thermometer drops.

H4, H8 and H16: The Diffusible Hydrogen Numbers

The H designator is a ceiling on diffusible hydrogen, measured in millilitres per 100 grams of deposited weld metal. Lower is better, and the number is the maximum allowed:

Designator	Max diffusible hydrogen	Typical use
H16	16.0 mL / 100 g	General purpose, less critical work
H8	8.0 mL / 100 g	Shop fabrication, repair, everyday code-adjacent work
H4	4.0 mL / 100 g	Structural, pressure, low-alloy and cold-weather work

AWS A5.1 lists these limits, along with covering moisture limits and improved-toughness requirements, as optional supplemental requirements, so the same E7018 core can be offered at several hydrogen tiers. Typical certified H4 results land around 2.1–3.9 mL/100 g, comfortably inside the limit. If you want the reasoning behind why those millilitres matter so much, the hydrogen-induced cracking discussion below picks up that thread.

The R Designator: Moisture-Resistant Covering

An R means the covering passed the absorbed moisture test as received, straight from the package. The Washington Alloy 7018 H4R data sheet describes the exposure condition as more than 9 hours at 27°C and 80% relative humidity. In plain terms: the rod tolerates humid shop air longer before its hydrogen performance drifts off spec. It buys handling time, not immunity. A rod left out overnight in a wet shop will still climb in hydrogen, and no R suffix changes that.

What the Suffixes Look Like on Real Packages

Three common products show how manufacturers combine these designators:

• Lincoln 7018 AC — classified E7018 H8 (Lincoln Electric data). Built to run on AC machines, capped at 8 mL/100 g hydrogen. A practical shop rod, not a cold-climate impact rod.
• Hobart 7018 XLM — classified E7018-1 H4R (Hobart datasheet). Toughness at −46°C, 4 mL hydrogen ceiling, moisture-resistant covering. This is the “checks every box” rod for outdoor structural and code work.
• ESAB Weld 7018-1 — classified E7018-1 H4. Improved toughness and low hydrogen without the R, which means standard storage discipline applies from the moment the box is opened.

Notice the pattern: H8 suits controlled indoor fabrication, H4 suits inspection-heavy and cold work, and R is a convenience layer on top. On a bridge job where the inspector will ask for the manufacturer’s typical test values, or in a shop running alloy steel welding electrodes on low-alloy base metal, the H4 and -1 designators are the ones worth paying for. On a bench repair in July, an H8 rod welds identically in the finished joint’s appearance but gives you less margin.

What Each Suffix Actually Buys You

Think of the suffixes as risk margins. -1 buys fracture resistance in the cold. H4 buys a lower hydrogen dose into a weld that may sit under high restraint. R buys hours of ambient tolerance before baking becomes necessary. Strip them away and you still have a perfectly good E7018; add them and you have a rod matched to a specific service condition. Match the suffix to the job’s temperature, restraint and inspection level, and you will never over- or under-buy a box of rods again.

Why the ‘8’ Matters: Low Hydrogen and Hydrogen-Induced Cracking

The final digit in E7018 is the one most beginners skip, and it is arguably the most important character in the code. The ’70’ tells you strength and the ‘1’ tells you position, but the ‘8’ tells you chemistry: this electrode belongs to the low-hydrogen (basic) covering family. That distinction separates a weld that quietly outlasts the structure from one that cracks three days after the inspector has gone home.

Where the Hydrogen Comes From

Hydrogen does not sneak in through shielding gas, because stick welding has no gas cylinder. It comes out of the electrode coating. Organic materials in a covering — cellulose, wood flour, organic binders — break down in the arc and release hydrogen gas straight into the weld pool. A basic covering is built around limestone (calcium carbonate) and fluorspar with very little organic content. As the Pinnacle Alloys/Praxair E7018 data sheet puts it, coverings high in limestone produce weld deposits low in hydrogen. That is the entire engineering purpose of the ‘8’.

Once dissolved in molten steel, hydrogen is extremely mobile. As the weld cools, it diffuses out of the bead and into the surrounding heat-affected zone (HAZ) — the thin band of base metal that was heated but not melted. If that zone has hardened into a brittle, martensitic microstructure and the joint is under restraint, the trapped hydrogen exerts pressure from inside the metal. The result is hydrogen-induced cracking, also called cold cracking or delayed cracking, because it can appear hours or even days after the weld is completed.

Why 6013-Type Rods Crack Harder Steels

This is where the fourth digit earns its keep on the job. Titania-type electrodes such as 6013 use coverings that produce relatively high hydrogen. On mild steel in an easy, low-restraint joint, that is usually harmless. On high-carbon steel, quenched-and-tempered alloy steel, or thick restrained members, the same rod can produce cracking that no amount of technique can rescue. As Lincoln Electric notes in its E7018 AC product literature, electrodes with other than low-hydrogen coverings may produce hydrogen-induced cracking in high-strength, high-carbon or low-alloy steels — which is exactly why structural procedures specify low-hydrogen fill and cap passes.

For the same reason, 7018 is the default for welding medium-carbon and low-alloy steels, including the 4130, 4140 and similar grades covered by our alloy steel welding electrodes guide. Deposit chemistry also matters: AWS limits E7018 weld metal to 0.15% carbon, 1.60% manganese, 0.75% silicon, and 0.035% each for phosphorus and sulfur — a composition that keeps the bead tough without pushing the HAZ toward brittleness.

Diffusible Hydrogen: The H4 and H8 Suffixes Explained

“Low hydrogen” is a category, not a precise number, so AWS A5.1 puts real values behind it. Every low-hydrogen classification is tested for diffusible hydrogen, measured in millilitres of hydrogen per 100 grams of deposited weld metal. The bare E7018 designation carries an 8.0 mL maximum, which is where the H8 suffix comes from. Published Pinnacle Alloys data shows E7018 diffusible hydrogen results of roughly 2 to 4 mL/100 g against that ceiling — modern rods typically run well under it.

H4 limits hydrogen to 4 mL/100 g, and H8R or H4R add moisture resistance on top. Inspectors do not take hydrogen control on faith: AWS A5.1 requires moisture content testing of low-hydrogen coverings as a core part of classification, and manufacturers publish typical and maximum values on their data sheets. Hobart Brothers’ 7018 XLM sheet, for instance, shows a typical deposit of 0.05% carbon and 0.93% manganese with Charpy V-notch impact values around 86 ft-lb (117 J) at −50°F, versus a 20 ft-lb specification minimum — toughness that only remains available if hydrogen stays low.

Practically, H4 buys three things: a wider safe window on restrained joints, a defensible paper trail when an inspector asks for consumable documentation, and reliable low-temperature toughness in cold weather. If you are welding structural steel to AWS D1.1 or pressure components under ASME Section IX procedures, those procedures frequently name the hydrogen suffix explicitly. Substituting a plain E7018 for an E7018 H4 where the procedure demands H4 is a documented non-conformance, not a judgment call.

That also explains the handling rules in the next section. A low-hydrogen covering is low-hydrogen when it leaves the factory, and stays that way only as long as you keep moisture out of it. Once a basic covering absorbs water, you are back to running a high-hydrogen rod — with the classification stamped on the package quietly no longer describing what is going into the joint.

Settings and Technique: Polarity, Amperage and Arc Length for 7018

Reading the number gets you the right rod. Setting the machine correctly is what gets you the weld. The good news is that 7018 is one of the more forgiving electrodes to run once you dial in three things: polarity, amperage, and arc length. Everything else is hand position and patience.

Polarity: Set It to DCEP

Standard E7018 is a basic-covered electrode designed to run on DC electrode positive (DCEP), also called reverse polarity or DC+. On DCEP most of the heat goes into the work through the electrode, the arc starts easily, and the covering burns off evenly to leave a stable, quiet arc. AC is also acceptable and is the reason 7018 variants exist for low-cost machines and field repair work; as Lincoln Electric’s 7018 AC data shows, the same rod simply wants a slightly hotter setting on AC to compensate for the alternating cycle.

DCEN (straight polarity) is generally not recommended for standard 7018. On DCEN the arc becomes wandering and unstable, penetration drops, and the covering tends to burn back toward the holder. If your arc looks erratic and the bead sits proud and cold, polarity is the first thing to check.

Amperage: Start From the Data Sheet, Not a Guess

Manufacturer typical operating procedures give you a starting window, not a fixed rule. Below are Lincoln’s published ranges for 7018 AC, which line up closely with what other manufacturers recommend for standard 7018:

Diameter	DC+ (DCEP)	AC
3/32 in (2.4 mm)	70–115 A	75–120 A
1/8 in (3.2 mm)	100–140 A	105–150 A
5/32 in (4.0 mm)	120–185 A	130–200 A
3/16 in (4.8 mm)	~160–240 A (typical)	~170–250 A (typical)

Within the window, move toward the lower end on thin material and out-of-position work, and toward the upper end on thick plate in the flat position. The tell-tales are simple: too cold and the rod sticks, the bead piles up round, and the sidewalls show lack of fusion; too hot and you get a fast, fluid puddle, undercut along the toes, and a bead that washes out flat.

Arc Length, Work Angle and Travel

7018 rewards a tight arc. Keep the length less than half the electrode diameter — for a 1/8 in rod that means roughly 1/8 in or less, close enough that you can hear a steady crackle rather than a hiss. A long arc lets oxygen reach the molten puddle and destroys the shielding the covering is working to provide, which shows up as porosity in the first few inches.

For a flat butt or fillet, hold a 10–15 degree drag (travel) angle from perpendicular and let the rod follow itself. As covered in our all position welding rod guide, 7018 is a true all-position electrode, but the technique changes with position: vertical-up only. Both Hobart’s 7018 XLM sheet and Pinnacle Alloys data explicitly state that vertical-down is not recommended. Running downhill on a basic covering lets the slag run ahead of the puddle and trap itself in the weld, and penetration suffers badly. See this vertical-up 7018 walkthrough for travel speed and weave length.

Weaving and What a Good 7018 Bead Looks Like

On a root or a narrow joint, a straight stringer is enough. On a cap, use a slow side-to-side weave, pausing briefly at the toes so the puddle wets into the edges without undercutting. Keep the weave width to about 2.5 times the electrode diameter; any wider and the puddle gets too fluid to control.

When it is dialed in, 7018 is one of the quietest rods you can run: a soft, steady arc, very little spatter, and a bead that comes out flat to slightly convex with a smooth, even ripple pattern. The slag lifts off in a clean skin if you tap it at the end. Deposition is efficient too, with ESAB’s Weld 7018-1 data listing roughly 1.2 kg per hour for a 3.2 mm rod at 110–140 A, so a 1/8 in rod covers ground faster than beginners expect. If you want to understand why stick still earns its place over other processes on structural work, the advantages of stick welding break down the portability and field case in detail.

7018 vs 6010, 6011, 6013 and 7014: Which Rod When

Now that you know how to decode the 7018 classification, it’s time to see where it fits amongst the other workhorses of stick welding. While all SMAW electrodes serve a purpose, each one has its own strengths, weaknesses, and ideal applications. Choosing the correct rod can be the difference between a structurally sound weld, and one that is prone to failure. With that being said, let’s break down the five most common electrodes and when to reach for each one.

Breaking Down The Common Electrodes

When comparing stick electrodes, the biggest factors to look at are penetration, polarity, position capability, and the flux type. These characteristics are what determine how each rod will perform under different conditions. The table below breaks down these key differences according to their AWS classifications:

Electrode	Flux Type	Polarity	Penetration	Positions	Best Used For
6010	Cellulose Sodium	DCEP Only	Deep	All Positions	Root passes, dirty steel, and pipe welding.
6011	Cellulose Potassium	AC or DCEP	Deep	All Positions	Farm and repair work on low-cost AC machines.
6013	Titania Potassium	AC, DCEP, or DCEN	Light to Medium	All Positions	Beginners, sheet metal, and cosmetic beads.
7014	Iron Powder Titania	AC or Either DC Polarity	Medium	Flat & Horizontal (Primarily)	High deposition and smooth beads on larger projects.
7018	Low-Hydrogen (Basic) with Iron Powder	AC or DCEP	Medium	All Positions (Except Vertical-Down)	Structural, code work, and high strength steels.

When To Choose Each Rod

6010 and 6011 are the go-to rods for penetration. The cellulose coverings of these electrodes create a forceful arc that can dig through rust, mill scale, and even some light contaminants. For this reason, 6010 (DCEP only) and 6011 (AC or DCEP) are heavily utilized for open root passes on pipe. They are extremely versatile positionally, however, their aggressive arc tends to be less forgiving for beginners.

6013 is the polar opposite in terms of arc characteristics. With its titania potassium covering, it provides an easy to control arc with minimal spatter. This makes it perfect for sheet metal work, tacking, and cosmetic beads. If you’re just getting your feet wet in stick welding, this rod is one of the easiest to start and restrike.

7014 takes the smoothness of a titania rod and adds iron powder to drastically increase deposition rates. This allows for quicker fills on thicker material while still laying down a clean, smooth bead. It’s best suited for flat and horizontal work, making it a staple for fabrication jobs that don’t require the low-hydrogen properties of 7018.

7018 is the strength focused rod of the group. Classified as a low-hydrogen electrode with medium penetration, 7018 is designed to produce tough weld metal with a minimized risk of hydrogen-induced cracking. This is crucial for structural steel, pressure vessels, and any code work. While it runs much quieter than a 6010, it comes with the trade-offs of being harder to restart, more sensitive to moisture, and requiring a much shorter arc length to run properly.

The Power Of Mixed Procedures

One of the most common practices throughout the industry is utilizing a mixed procedure, specifically a 6010 or 6011 root pass paired with 7018 fill and cap passes. This technique utilizes the deep, digging penetration of cellulose rods to achieve full joint penetration on a root, while the low-hydrogen properties of 7018 protect the completed weld from delayed cracking in the subsequent passes. This hybrid approach is seen throughout structural and pipeline work and is a prime example of utilizing each electrode to its maximum potential.

At the end of the day, there is no “best” rod, only the correct rod for the job. If you need to burn through grime on a repair, reach for 6011. If you need a pristine bead on sheet metal, utilize 6013. If the joint is governed by a structural code, however, the unmatched toughness and hydrogen control of 7018 will always be the gold standard.

Storage, Baking and Handling: Keeping 7018 Low-Hydrogen

The biggest selling point of E7018 is its low-hydrogen covering, but that advantage is only as good as the condition of the rods themselves. Once a box of 7018 is opened, its basic flux coating begins to absorb moisture from the surrounding air. If that moisture is driven into the arc, it breaks down and introduces hydrogen into the puddle. This raises the level of diffusible hydrogen in the weld metal, which in turn greatly increases the risk of porosity and delayed cold cracking. For those looking to understand why this rod is held in such high regard over others, it’s worth revisiting the advantages of stick welding in the first place, as its low-hydrogen reliability is one of them.

The Enemy: Moisture and Diffusible Hydrogen

When moisture is present in a damp 7018 covering, the arc’s heat converts it into atomic hydrogen. This hydrogen is small enough to slip into the molten weld and later migrate into the heat-affected zone as the joint cools. With enough hydrogen, enough tensile stress, and a hard, susceptible microstructure, all three combine to create hydrogen-induced cracking. On a more immediate level, excess moisture is also the most common culprit for what welders refer to as “starting porosity”. You’ll often see tiny, pinhole-sized gas pockets at the very beginning of a bead with damp rods, long before any delayed cracking would occur.

Across the board, open containers and long atmospheric exposure are the most common shop causes of hydrogen pickup in 7018 coverings. This is exactly why manufacturers put so much emphasis on storage, and why products such as Hobart 7018 XLM specifically market their ‘extra low moisture’ formulation to prevent starting porosity in the first place.

Proper Storage: Ovens, Packaging, and Quivers

To keep hydrogen out, 7018 rods must be kept dry from the moment they’re unsealed. Major manufacturers such as Hobart, Pinnacle Alloys and Washington Alloy all specify storage ovens controlled at 250-300°F (120-150°C). Keeping them at this temperature prevents any moisture from re-absorbing while in holding.

When not in an oven, a few simple habits go a long way:

• Keep the original packaging: Only open what you’ll reasonably use for the shift. The hermetically sealed box is your first line of defense against ambient humidity.
• Use rod quivers: For short jobs away from the oven, a heated or well-insulated rod quiver is far better than leaving rods loose on a bench or in an open bucket.
• Be cautious of time: Even rods labeled with the R designator (as seen on products like Washington Alloy 7018-H4R) have limits. The R designation only covers an absorbed moisture test at 80°F/80% RH for more than 9 hours, not unlimited exposure.

Reconditioning Damp 7018

Sometimes, despite best efforts, rods are left out overnight, forgotten in an open can, or pulled from an unverified storage setup. For these cases, reconditioning can salvage them, but it must be done correctly. The widely accepted procedure is to place exposed electrodes in a 250°F oven, slowly increase to 600°F (about 315°C), and bake for one hour. After baking, rods must be transferred to a holding oven at 250-300°F (120-150°C) until they’re used. Never attempt to rush this with an open flame, and never bake rods that are heavily rusted or have a flaking, cracked covering.

It’s important to remember that the suffixes that buy you leeway, such as H4, H8, or H4R, buy time, not immunity. Once exceeded, the only safe remedy for most shop work is the bake outlined above, or to discard them entirely for any code-governed welds.

Lastly, when in doubt, discard old or rusty rods. No amount of baking is worth the risk of a hidden hydrogen crack, especially when the fix is far cheaper than NDT rejection or a structural failure. For 7018, dryness isn’t optional. It’s part of the specification.

Common 7018 Mistakes and How to Fix Them

Here is the good news about E7018: once you understand what the classification promises, most problems stop being mystery faults and start being identifiable habits. Almost every bad 7018 bead traces back to arc length, polarity, amperage, rod condition, travel direction, or cleanup. The rod itself is rarely the culprit, which is part of the reason stick welding still dominates jobsites where reliability matters (see our advantages of stick welding guide for the bigger picture). Work through this checklist symptom by symptom and you will fix the cause instead of fighting the symptom.

The Troubleshooting Checklist: Symptom, Cause, Cure

Mistake	What you see	Why it happens	The fix
1. Arc too long	Porosity, heavy spatter, a loud hissing crackle, dull lumpy bead	The flux shielding and iron powder can no longer protect the puddle	Keep the arc under half the electrode diameter and drag tight
2. Wrong polarity (DCEN)	Wandering, unstable arc, poor starts, cold lumpy deposits	Standard 7018 is designed for DCEP (reverse) or AC	Switch to DCEP; use AC only if DC is unavailable
3. Amperage too cold	Stuck rods, narrow ropey bead, cold lap at the toes, sluggish puddle	Machine too small for the diameter, or setting guessed	Raise in 5–10 A steps, or step down a diameter on thin stock
4. Amperage too hot	Undercut along the toes, flat watery puddle, excessive fluidity	Too much heat for that diameter and position	Trim amperage; out-of-position, cut roughly 15% below flat settings
5. Damp or old rods	Starting porosity, popping at arc initiation, fine spatter, black sooty beads	Basic coverings absorb moisture from open air	Use fresh rods from sealed packaging, store in a quiver or rod oven
6. Vertical-down welding	Cold lap, lack of fusion, slag washed into the weld	Fast travel plus heavy slag outruns the puddle	Weld vertical-up with a tight arc and a small weave
7. Dirty stops and starts	Slag inclusions, porosity at tie-ins, dark streaks	Slag dragged into the next pass or crater left unfilled	Chip, grind and wire brush every pass before overlapping
8. Restart and stub problems	Crater cracks, failed restrikes, burned-back stubs	Restriking on a cooled crater, or burning a stub too short to hold an arc	Back up and restart on solid weld metal; discard stubs you cannot control

The Two Mistakes That Cost the Most

Long arcs and wet rods deserve extra attention because both destroy low-hydrogen performance at the same time. Excessive arc length is the single most cited cause of porosity with low-hydrogen electrodes; you are literally breaking the gas envelope that the covering was engineered to provide. Lincoln Electric’s published guidance for E7018-type electrodes recommends a short arc, minimal manipulation and moderate weaving, which keeps the puddle narrow enough to protect itself. If your bead is wide, flat and speckled with pores, shorten the arc before touching anything else.

Moisture is the other silent killer. Starting porosity at the beginning of a bead is the classic fingerprint of a damp covering, because the moisture releases hydrogen the moment the arc strikes. This is exactly why extra-low-moisture products exist: Washington Alloy’s 7018 H4R datasheet specifies low diffusible hydrogen and moisture-resistant packaging precisely so that the rod stays weldable longer after the box is opened. The moisture-resistant covering buys you time on the job, not immunity at the end of the week.

Vertical-down deserves a special warning. It works beautifully for fast, thin-cellulose rods, but 7018 deposits too much metal and generates too much slag to survive a fast downward run. The result is cold lap and trapped slag that radiographic inspection will find immediately. Move to vertical-up: short arc, small keyhole-free weave, patient upward travel. Our all position welding rod guide covers how 7018 behaves across flat, horizontal, vertical and overhead, and Welding Tips and Tricks’ vertical-up walkthrough is a solid companion demonstration.

Finally, fix your restart habits. Never end a pass by simply pulling away, because the shrinking crater concentrates stress and often cracks; step back, fill it and lift. And restrike a rod promptly after a short stall. A cooled stub holds a stiff, stubborn arc that splatters and contaminates the tie-in, while a stub burned down to a stubby nub will burn your fingers and arc erratically. Replace it. A few cents of electrode is nothing compared to a rejected weld.

Where 7018 Is Used: Applications, Codes and Real Jobs

A weld classification only earns its keep when something real is riding on the weld. On a garden gate or a rusty trailer fix, almost any rod will do. On a beam splice, a bridge girder, a boiler seam or a pipeline tie-in, the welding procedure specification (WPS) will name the exact filler metal to use, and more often than not it names E7018. That is the practical meaning of the code on the box: it is the rod an inspector can accept without a second conversation, because the classification itself is the certification.

The Jobs That Call for 7018

Typical applications listed for 7018 electrodes run across most of heavy industry:

• Pipeline work: mainline tie-ins, repair and integrity digs, where low hydrogen and positional capability are non-negotiable.
• Boiler and pressure vessel fabrication: thick-walled seams that will later be X-rayed.
• Structural fabrication and field erection: buildings, bridges, stadiums and industrial frames.
• Shipbuilding, offshore rigs and marine work: hulls, decks and legs subject to cyclic loading.
• Power plants and petrochemical units: high-temperature piping and heavy plate assemblies.
• Heavy equipment repair and general fabrication: buckets, frames, frames and anything that must not crack in service.

Manufacturers build variants around those niches. Lincoln’s IronArc 7018 MR is classified AWS E7018 H4R and positioned for pipeline, pipe repair and integrity work, where a four-millilitre hydrogen ceiling and a moisture-resistant covering matter more than deposition rate (Lincoln IronArc 7018 MR product data). Hobart’s 7018 XLM carries AWS, ASME, ABS and CWB approvals and is aimed at offshore and power-plant construction (Hobart 7018 XLM datasheet). Same base rod, different paperwork and testing to match the job. It is also worth remembering why SMAW survives in these environments at all: it goes where wire feeders cannot, as covered in Advantages of Stick Welding: Why SMAW Still Wins.

The Codes Behind the Classification

Several standards reference the same four digits, which is why 7018 travels so well across industries and borders:

Standard	What it covers
AWS A5.1/A5.1M:2025	The base specification for carbon steel SMAW electrodes, including E7018 requirements for tensile strength, toughness, hydrogen and testing.
AWS D1.1 (Structural Welding Code)	Governs welded steel structures in the US; procedures commonly specify E7018 for fills, caps and complete-joint-penetration grooves.
ASME Boiler and Pressure Vessel Code (ASME SFA-5.1)	References AWS A5.1 for filler metals used in boilers, pressure vessels and power piping.
CSA W48 (Canada)	Classifies the same rod as E4918, reflecting a 490 MPa tensile requirement instead of 70 ksi.
ABS / ABS-CB approvals	American Bureau of Shipping acceptance for ship, offshore and marine fabrication.

That last row matters more than it looks. Marine and offshore builders often require rod approvals from the certifying society as well as the welder’s qualification, and classification approvals are a large part of boiler and ship work too, which is the daily reality of shops like Alamo Welding & Boiler Works and AJ Marine Welding. For structural steels that are quenched and tempered or low-alloy, the procedure may push beyond plain E7018 into territory covered by Alloy Steel Welding Electrodes.

Inspection Is Where the Code Gets Real

In these environments the weld is usually inspected by radiography or ultrasonic testing, backed by tensile and impact testing of the deposited weld metal. That is exactly what E7018 certifies: a minimum 70 ksi tensile strength plus the Charpy V-notch values listed in the standard. Where low-temperature toughness is required, procedures specify an E7018-1 variant, impact tested at −46°C (−50°F), for arctic pipelines, cryogenic-adjacent service and cold-climate structures.

The takeaway is simple: when the drawing says E7018, it is specifying a verified package of strength, position, chemistry and hydrogen control, not asking for a brand. Match the full classification, including any H4, H8 or −1 suffix, to the procedure, and the inspector and the engineer are already on your side.

Practical Buying Guide, Tips and Final Takeaways

Now that you can read the code, buying 7018 becomes a straightforward decision instead of a guess. The last piece of the puzzle is matching the rod in your hand to the joint in front of you.

Choosing the Right Diameter

Standard 7018 rods come in four sizes: 3/32, 1/8, 5/32 and 3/16 inch. Each one has a job.

• 3/32 inch: Best for thin material, root passes and tight joints where heat control matters more than speed. It runs cool and gives you the most control.
• 1/8 inch: The workhorse. If you only buy one size, buy this. It handles light fabrication through medium plate, runs roughly 90–150 A depending on position and polarity, and works in all positions.
• 5/32 inch: A step up for thicker stock and faster fill on structural work.
• 3/16 inch: Built for thick material and high-deposition flat and horizontal work. This size is generally restricted to flat and horizontal positions, so it is not a shop-everything rod.

Deposition rate rises sharply with diameter, which is why diameter choice is really a productivity choice. At optimum parameters, a 3/32 rod deposits roughly 1.8 lb per hour, while a 3/16 rod deposits around 5.2 lb per hour. That is nearly three times the metal for the same hour of welding.

Diameter	Approx. Deposition	Typical Use
3/32	~1.8 lb/hr	Thin stock, roots, control work
1/8	Mid-range	General shop, all positions
5/32	Higher	Plate, structural fill
3/16	~5.2 lb/hr	Thick, flat/horizontal only

What to Look for on the Package

Do not just read the big number. Check the full AWS classification, including any suffix. A box marked E7018-1 H4R tells you the rod is a 7018 with improved low-temperature toughness, a diffusible hydrogen limit of 4 mL per 100 g, and a moisture-resistant covering. A bare “7018” with no suffix leaves those three questions unanswered.

Also look for the batch or lot number, and pull the manufacturer’s data sheet before you buy. Reputable sheets list tensile strength, yield, elongation, Charpy V-notch impact values and diffusible hydrogen. Those are the numbers a QC inspector will ask about, and they vary between brands even within the same E7018 classification. For reference, the governing standard is AWS A5.1/A5.1M:2025, the current edition; older A5.1:2012 listings are now marked historical, so treat outdated data sheets accordingly.

How Many to Buy, and How to Store Them

Buy by the box, not by the handful. Rods sitting loose in a drawer absorb moisture, and a 7018 that has gone damp loses the exact property you paid for. Budget for storage at the same time: a rod quiver for the field, or a rod holding oven at 120–150°C (250–300°F) for the shop. If you weld structural or code work regularly, the oven is not an luxury accessory; it is part of the consumable system. Our All Position Welding Rod Guide covers how 7018 fits alongside other all-position rods if you are still building out your kit.

Safety Still Applies

“Low hydrogen” describes the weld metal, not the fume. 7018 coverings still produce welding fumes and trace amounts of harmful constituents, so use adequate ventilation or fume extraction, wear your hood and follow the Safety Data Sheet. If you are new to stick, our Advantages of Stick Welding piece explains why SMAW remains the default for field work despite these handling requirements.

The Code in One Sentence

E7018 means: a stick electrode, minimum 70,000 psi tensile strength, usable in all positions, with a low-hydrogen basic covering that runs on AC or DCEP.

Final Takeaways

1. Read the full classification including suffixes like -1, H4 and R.
2. Match diameter to material thickness and position, not to price.
3. Compare data sheets for tensile, Charpy and diffusible hydrogen values.
4. Store rods dry, and never weld a questionable rod.
5. Take amps from the manufacturer’s table, then adjust about 15% down out of position.

The four digits on that box were never decoration. Once you can read them, you can walk into any supply house, pick the correct rod off the shelf, and know exactly what it will do before the arc ever strikes. For more on electrode selection beyond carbon steel, see our guide to Alloy Steel Welding Electrodes.

Frequently Asked Questions

What does the number 7018 mean on a welding rod?

It is the AWS classification E7018: ’70’ means the weld metal has a minimum tensile strength of 70,000 psi, ‘1’ means it can be used in all welding positions, and ‘8’ identifies a low-hydrogen, iron-powder covering usable on AC or DCEP. The leading ‘E’ simply stands for electrode.

What does the E in E7018 stand for?

E stands for electrode, meaning a consumable that carries welding current through a covered (flux-coated) stick. Bare filler rods use ‘ER’ instead, as in ER70S-6 for MIG/TIG welding.

Is 7018 stronger than 6013?

No. Both deposit weld metal with a 70,000 psi minimum tensile strength. The difference is the covering: 7018 is low-hydrogen and all-position with better toughness and crack resistance, while 6013 is a titania coating that is easier to start and better for sheet metal and cosmetic work.

What polarity should I run 7018 on?

DCEP (direct current electrode positive, also called reverse polarity) is preferred, and AC is acceptable. Standard 7018 should not be run on DCEN, which gives poor arc stability and erratic penetration.

What do H4, H8 and R mean after E7018?

H4, H8 and H16 are diffusible hydrogen limits — 4, 8 and 16 milliliters of hydrogen per 100 grams of deposited weld metal. R means the covering passed an absorbed-moisture resistance test, so the rod tolerates humid storage better before use.

Do 7018 rods need to be baked or stored in an oven?

Yes, for code or structural work. Manufacturers specify holding ovens at 250-300°F (120-150°C), and rods exposed to air for a long time can be reconditioned by slowly ramping to 600°F and baking one hour. Casual hobby use tolerates rod quivers, but damp rods cause porosity and cracking risk.

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

Most manufacturer data sheets recommend roughly 90-150 amps for 1/8 inch depending on polarity and position, with Lincoln listing 100-140 A on DC+ and 105-150 A on AC. Reduce the setting about 15% for vertical and overhead work.

Can I weld vertical down with 7018?

No. Manufacturer instructions list all positions except vertical down, because the fast travel rate and slag interference risk lack of fusion. Run 7018 vertical-up with a weaving technique.

What is the difference between E7018 and E7018-1?

The -1 suffix means the electrode passed supplemental impact testing, requiring 27 J (20 ft-lb) Charpy V-notch at -46°C (-50°F) instead of the standard -29°C. Use -1 or H4 grades when welding in cold environments or to toughness-critical specifications.

Where is 7018 welding rod typically used?

Structural steel, bridges, pipelines, boilers and pressure vessels, shipbuilding, offshore platforms, power plants, and general fabrication where inspected, code-quality welds are required. It is the default fill and cap rod in most structural welding procedures.