Welding Rod Number Meaning: How to Read E6013 and E7018

A hobbyist builder once burned through an afternoon because he grabbed a box of E6013 rods for a structural repair that the inspection sheet explicitly called for E7018 — the weld looked fine to him, but it failed the paperwork. Every number printed on a welding rod is a set of instructions, and learning to read it takes about five minutes.

What a Welding Rod Number Actually Is (and Why It Exists)

A builder once lost an afternoon because he grabbed a box of E6013 rods for a structural repair that the inspection sheet explicitly called for E7018. The weld looked perfectly fine to him, but it failed the paperwork. That story is the whole point of this article: the number printed on a welding rod is not a product label or a marketing badge. It is a specification, and specifications get checked.

So, what is a welding rod number? At its simplest, it is a standardized classification code published by the American Welding Society (AWS). The code tells you, in a fixed order, four things about a stick electrode: what kind of electrode it is, how strong the weld metal it deposits will be, which welding positions it can be used in, and what the flux coating is made of plus which current it runs on. When someone asks what “E7018” means, they are asking for a translation of exactly those four facts.

What the number does not tell you matters just as much. It will not tell you the amperage range, how to prep the base metal, whether the steel is mill scaled or painted, or whether you have the skill to run it overhead. Those decisions come from the procedure, the joint, and the welder — not from the digits.

Two Different Systems: Stick Electrodes and Filler Wires

The familiar four-digit codes belong to covered stick electrodes used in shielded metal arc welding, or SMAW. The flux coating on the rod burns to create shielding gas and slag, which is why these rods are called “covered” electrodes.

Wire processes work differently. MIG (GMAW) and TIG (GTAW) feed a bare or lightly treated wire from a spool or straight lengths, and those get a different code: ER. A spool marked ER70S-6 reads like this — ER means electrode or filler rod, 70 means 70,000 psi tensile strength, S means solid wire, and 6 describes the deoxidizer chemistry in the wire. The same logic runs through aluminum filler wire such as ER4043 and ER5356, which is covered in detail in our Aluminum MIG Welding: The Complete Practical Guide. Flux-cored wires use an E71T-style code where the T simply means tubular.

Why Standardization Matters

Before classification codes, a welder bought “a half-inch rod that runs on AC” and hoped for the best. Today, a structural drawing, a written welding procedure specification (WPS), and an inspector all reference the same alphanumeric string. If the WPS says E7018, the box in your hand has to say E7018 too. Standardization also makes purchasing predictable: you can buy rods from different manufacturers and know they meet the same minimum requirements.

Those requirements live in AWS specification documents:

• AWS A5.1 — carbon steel electrodes for SMAW, the standard behind E6010, E6013, E7018 and friends
• AWS A5.18 — carbon steel filler metals for GMAW and GTAW, covering the ER70S family
• AWS A5.9 — bare and corrosion-resistant filler wires, including stainless ER308L and ER316L

Outside North America, the same rods are often classified under ISO 2560 or EN ISO standards, which use a completely different format. An EN ISO designation such as E 38 0 B R 32 encodes an E5013-class mild steel rod using its own logic, so a European box will not read like an American one. The AWS electrode classification breakdown from Hobart Brothers is a useful side-by-side reference if you work with both systems.

Once you accept that the number is a compressed spec sheet rather than a brand name, the rest of the decoding becomes mechanical. The next section walks through each digit, one position at a time.

Reading the Number Digit by Digit: E, 70, 1, 8

Pull a stick electrode out of the box and you will usually find a short code stamped or printed along the flux: E7018, E6013, E6010. That code is not a catalog number or a brand name. It is a compressed specification, and each character answers one specific question about the weld metal you are about to deposit. Learn those four questions and you can read any stick rod in seconds.

Position	Example	Question it answers
1st character	E	What kind of consumable is it?
2nd–3rd digits	70	How strong is the deposited weld metal?
4th digit	1	What welding positions can it handle?
5th digit	8	What is in the coating, and which current works?

The American Welding Society lays out these rules in its A5-series standards, and manufacturer references such as Lincoln Electric’s AWS classification guide follow the same structure.

The Leading Letter: What Kind of Consumable It Is

The letter E simply means a covered electrode for arc welding: a solid core wire wrapped in flux, used in SMAW (stick) work. Change that letter and you change the whole category. An R prefix marks a welding rod or brazing electrode, and an A marks filler metals used with gas tungsten arc (TIG) and other processes. An ER-coded rod such as ER70S-2 is a different animal: no flux coating, and shielding comes from the gas bottle rather than the flux.

The First Two Digits: Minimum Tensile Strength

The next two digits are the strength rating, expressed in thousands of psi (ksi) — 70 means the deposited weld metal is guaranteed to reach a minimum tensile strength of 70,000 psi. Tensile strength is simply the maximum stress a material survives before it pulls apart in a destructive test. It is measured on the weld metal itself, not the rod and not the base plate, which is why the same number shows up regardless of what steel you are joining.

Practically, E60xx rods deposit weld metal rated at 60,000 psi, E70xx at 70,000 psi, and the series climbs from there — E80, E90, E110 and beyond for high-strength low-alloy steels.

The Third Digit: Welding Position Capability

This is the digit most often ignored, and the one that causes the most field trouble. A 1 means the electrode is qualified for all positions: flat, horizontal, vertical and overhead. A 2 limits it to flat work and horizontal fillets only. A 4 also covers all positions but signals a special electrode design.

So E7018 will run overhead on a ladder, while E7024 will not, despite both being 70 ksi rods. Use a position-2 rod out of position and you get sagging, washed-out beads and a weld that fails inspection. Position limits also appear in qualification documents; all position welding rod guides cover which rods belong in which situation.

The Fourth Digit: Coating and Current

The last digit describes the flux chemistry and, by implication, the current you can run. Low digits (0, 1) are cellulose-based rods that dig deep; middle digits cover titania and iron powder types; 7 and 8 are low-hydrogen coatings. In E7018, the 8 tells you it is a low-hydrogen, iron-powder coating — the rod known for smooth arcs, friendly slag and structural-grade weld metal. The box label confirms the current it accepts: AC, DC straight or DC reversed.

Run through it once more with E6013: E = covered electrode, 60 = 60,000 psi minimum tensile strength, 1 = all positions, 3 = rutile (titania) coating, typically run on AC or DC. Same four questions, different answers.

When the Code Gets Longer: Alloys and Hydrogen Suffixes

Four digits are only the baseline. Electrodes for higher strength classes or service above room temperature carry extra characters, and where those characters sit changes how you read the number. In codes such as E7018-A1, E8018-B3 or E11018-M, the tensile strength expands to three digits (70, 80, 110 ksi) while the trailing letters describe alloy additions: A1 is molybdenum-bearing weld metal for heat-resistant steel, B3 is chromium-moly. This is the family covered in guides to alloy steel welding electrodes.

Letter suffixes carry their own limits. H4, H8 and H16 set maximum diffusible hydrogen in millilitres per 100 grams of deposited weld metal: H4 allows 4 ml per 100 g, H8 allows 8, and so on. Lower hydrogen means less risk of cold cracking in restrained joints, which is the whole reason E7018 exists. Other suffixes such as -Z flag special chemistry requirements. None of them change the core four-part reading.

The First Two Digits: Tensile Strength and Matching Steel

The first two digits after the prefix are the part most welders memorize first, because they answer the question everyone actually asks: how strong is this weld going to be? Before decoding them, it helps to know what tensile strength really means. A tensile test pulls a machined bar of metal until it breaks, then measures the maximum stress it survived. That figure is usually written in ksi, where 1 ksi = 1,000 psi. So the “70” in E7018 is a promise that the deposited weld metal — the filler you actually lay into the joint — will hold at least 70,000 psi (roughly 480 MPa) in tension before it fails.

That is a minimum, not a typical value, and there is a companion number behind it: yield strength, the point where the metal starts to stretch permanently. E7018 weld metal is specified with a typical minimum yield around 57,000–58,000 psi. If that gap surprises you, you are not alone — steel only feels “stronger” than its tensile rating until you remember that yield is where permanent deformation begins, not where the bar snaps.

What the 60 and 70 Families Actually Share

The “60” prefix covers a whole crowd of familiar rods. E6010, E6011, E6012, E6013 and E6019 all sit in the same 60,000 psi minimum tensile class, even though their coatings, penetration and ideal applications are very different. This is worth repeating: the strength digits say nothing about penetration, position or current. Two rods can carry identical strength numbers and behave nothing alike under the arc. The full breakdown of what each digit controls is covered in our guide to reading welding rod numbers.

According to the Lincoln Electric’s AWS classification reference, classifications run from the familiar E60xx and E70xx all the way through E110xx and beyond, each step up corresponding to a stronger deposited weld metal with its own chemical recipe.

Class	Min. tensile strength	Typical min. yield	Common electrodes	Typical use
E60xx	60,000 psi (415 MPa)	50,000 psi	E6010, E6011, E6012, E6013, E6019	Light fabrication, sheet, farm repair, root passes
E70xx	70,000 psi (480 MPa)	57,000–58,000 psi	E7014, E7018, E7024	Structural steel, pipe, general fabrication
E80xx	80,000 psi (550 MPa)	Varies by classification	E8018 variants	High-strength low-alloy (HSLA) steel, pressure piping
E90xx	90,000 psi (620 MPa)	Varies by classification	E9018 variants	HSLA, heavy equipment, bridge components
E100xx	100,000 psi (690 MPa)	Varies by classification	E10018 variants	Quenched-and-tempered high-strength steel
E110xx	110,000 psi (760 MPa)	Varies by classification	E11018-M	HSLA, military, mining and off-road structures

Matching the Electrode to the Base Metal

Here is the part beginners find counterintuitive: you almost never need a rod that is exactly as strong as the plate. Welding ordinary A36 mild steel (minimum tensile around 58,000 psi) with E7018 is standard practice on nearly every job site, because the weld metal over-matches the base metal slightly and the joint is limited by the weaker parent steel anyway. Under-matching — using E6010 on stronger steel — is sometimes deliberate too, especially on thin or heat-treated material where you want the weld to be the ductile fuse rather than the hard point.

That cracking risk is why the Hobart Brothers electrode classification guide emphasizes that E8018, E9018, E10018 and E11018 rods are built for high-strength low-alloy steels and frequently come with preheat requirements and strict hydrogen control. If you are moving into that territory, our Alloy Steel Welding Electrodes: Selection, Use & Safety guide covers the alloy-specific rods and their handling rules.

Toughness: The Qualification You Cannot See in the Number

Tensile digits tell you strength, but they say nothing about toughness — the weld metal’s ability to absorb impact without fracturing, especially at low temperature. AWS A5.1 lists impact-tested variants of the common classifications, with Charpy V-notch testing performed at specified temperatures (often −20°F or −40°F). When a project falls under AWS D1.1 structural requirements or a cold-climate service condition, the WPS will call for a toughness-qualified rod, and a plain “E7018” box may not satisfy it. Always read the full classification and the certification paperwork, not just the digits.

The Third Digit: Welding Position Codes Explained

If the first two digits tell you how strong the weld will be, the third digit tells you where you’re allowed to make it. It’s the character most beginners skip right past, and it’s the one that decides whether a rod that works beautifully on a bench is useless once you’re lying on your back under a trailer.

In the AWS classification system, the third digit of a stick electrode code is the position designation. As Lincoln Electric’s AWS classification reference lays it out, there are effectively three values you’ll run into in normal shop work.

Digit	Positions allowed	Typical electrodes
1	All positions: flat, horizontal, vertical (up or down), and overhead	E6010, E6011, E6013, E7015, E7018
2	Flat and horizontal fillet welds only	E7024, E7027
4	All positions, but with a special electrode design or restricted application	Rare, application-specific rods

What “All Position” Actually Means

AWS defines four basic plate positions. Flat is welding down onto a joint sitting below the arc. Horizontal is running a bead along a vertical face, fighting gravity’s pull on the puddle sideways. Vertical is welding up or down a seam that runs floor to ceiling. Overhead is the hard one: you’re underneath, and molten metal wants to drip on you. A rod stamped with a 1 in the third position, like E6013 or E7018, is qualified for all four. That’s why they’re the default choices for pipe, repair work, and anything that can’t be rolled into the flat position. Our All Position Welding Rod Guide breaks down which rods behave best in each of them.

Why the Position Digit Changes Deposition Rate

Position capability and deposition rate trade directly against each other. A rod that has to hold a puddle overhead needs a light, fast-freezing puddle, and that limits how much metal it can put down per pass. A rod that only ever runs flat can use a heavy, slow-freezing slag system plus iron powder in the coating, which dramatically boosts output.

That’s exactly what E7024 is. It’s a “fast-fill” iron powder rod: in flat and horizontal fillet work it runs at high amperage, lays a wide, fluid bead, and fills a big joint in a fraction of the passes a 7018 would need. Flip it overhead, though, and the puddle sags, the slag runs, and you get a mess. The 2 in the third position is telling you that upfront. If you want the same 70,000 psi strength out of position, you step up to E7018 and accept the slower fill rate.

Fillet and Groove Positions: 1F–4F and 1G–4G

Welding standards don’t just say “overhead” on a drawing; they label the joint. Fillet welds are numbered 1F (flat), 2F (horizontal), 3F (vertical), and 4F (overhead). Groove welds use the same scale with a G: 1G through 4G. Pipe adds its own set, including 5G for a fixed horizontal pipe where you must weld vertical and overhead positions without rotating the joint, and 6G for an inclined pipe, widely considered the toughest common qualification.

These labels connect directly to the electrode’s third digit. You cannot use a 2-position rod on a 3G or 4G groove, and a WPS will explicitly restrict the electrode to the positions it’s certified for.

How Position Limits Show Up on WPS and Qualification Tests

Under AWS D1.1, welder performance qualification is issued by welding position. A welder qualified in the flat position is not automatically qualified to weld overhead; each position has to be tested and recorded. The same principle applies to the procedure itself: a WPS qualified for 1F fillets doesn’t give you blanket permission to hang a beam and weld 4F, and the electrode listed in that WPS is the electrode you use. Hobart Brothers’ electrode classification article makes the same point: the position digit is a qualification boundary, not a suggestion.

Two Realistic Scenarios

Production shop, flat fillet work: building I-beams or tank shells on rotators, everything sits flat. E7024’s high deposition rate wins, labor costs drop, and the position restriction never bites because nothing goes out of position.

Open-root pipe in the field: the joint is fixed, you’ll weld flat, horizontal, vertical, and overhead on a single circumpference, and rotation may not be possible. A 2-position rod is disqualified before you strike an arc. E6010 for the root, E7018 for the fill and cap, both stamped with a 1.

Read the third digit first when you know the joint geometry, and you’ll never buy a rod that can’t legally touch the work in front of you.

The Fourth Digit: Coating Types, Current, and Hydrogen Designations

The last digit of a stick electrode code is the one beginners skip, and it may be the most useful. The first three digits tell you strength and welding position; the fourth tells you what the flux coating is made of, how it burns, and which current your machine must put out. Change that digit and you change the rod’s whole personality, which is why an E6010 and an E7018 behave like different tools despite looking similar.

What the Flux Coating Actually Does

That dull sheath around the core wire is not decoration. As it burns it:

• Shields the puddle — the coating breaks down into gas that protects molten metal from oxygen and nitrogen, which is one reason stick welding remains so versatile on job sites.
• Builds slag — the molten covering floats up and freezes into a crust that protects the cooling bead and shapes its profile.
• Controls the arc — ionizing materials like potassium make the arc easier to restart, iron powder boosts deposition, and other ingredients raise or soften penetration.
• Deoxidizes — scavengers such as silicon, manganese, and titanium pull gas and impurities out of the puddle.
• Releases hydrogen — cellulose and moisture in the coating are the main source of diffusible hydrogen, and therefore the cracking risk.

Coating Digit by Coating Digit

Digit	Coating type	Typical rod	Current	Character
0	High cellulose sodium	E6010	DC+ (reverse) only	Deep, forceful penetration; fast-freezing arc; harsh spatter
1	High cellulose potassium	E6011	AC or DC+	E6010 behavior with a smoother AC arc; farm and repair favorite
2	High titania sodium / rutile	E6012	AC, DC-, or DC+	Moderate penetration, soft arc, easy starts
3	High titania potassium (some low-hydrogen sodium types)	E6013	AC or DC	Soft, quiet, shallow arc; beginner friendly
4	Iron powder, high recovery	E7024	AC, DC-, or DC+	“Fast-fill” flat and horizontal production rod
5	Low-hydrogen potassium, optional iron powder	E7014	AC or DC+	Low hydrogen with faster travel and easier AC use
6	Iron powder with rutile	E7027	AC, DC-, or DC+	Heavy horizontal fillets on plate and pipe
7	Low-hydrogen sodium	E7015	DC+ only	Old-school low-hydrogen bead; strict storage
8	Low-hydrogen potassium plus iron powder	E7018	AC or DC+	Smooth arc, high deposition, low hydrogen workhorse
9	Special (defined by the manufacturer)	varies	varies	Reserved for proprietary or special-purpose coatings

The split that matters most is cellulose versus low hydrogen. Digits 0 and 1 mark cellulose coatings: they run hot, dig hard, and suit root passes on open-root pipe, dirty steel, and out-of-position work, but they dump more hydrogen into the puddle. Digits 5, 7, and 8 mark low-hydrogen coatings, the family structural codes prefer. Details of each member are covered in our all-position welding rod guide.

Reading the Suffixes: Alloys and Hydrogen Levels

The digits are not always the end of the code. Anything after the fourth digit is a suffix, and the most important ones are:

• -A1, -B1, -B2, -B3, -C1 and similar — alloy additions. E7018-A1 is a chromium-molybdenum rod for heat-resistant steels. These move you into alloy steel electrode territory, where strength, temperature rating, and preheat requirements all shift.
• -G — an unspecified chemical composition defined by the manufacturer, common on specialty rods and a reminder to read the data sheet.
• -H4, -H8, -H2 — diffusible hydrogen limits in milliliters per 100 grams of deposited weld metal. An E7018-H4 rod is limited to 4 ml per 100 g under AWS classification requirements, H8 to 8 ml, and H2 to 2 ml.
• -Z — a desulfurized, low-manganese designation for corrosion-resistant or sulfur-sensitive service.

Why care about hydrogen? It is the classic cause of cold cracking in restrained, thick, or high-strength joints. It diffuses into the heat-affected zone, collects at grain boundaries, and can open a crack hours after a bead that looked perfect. Low-hydrogen electrodes must therefore stay dry: manufacturer storage and re-drying guidance and ESAB’s storage guidance both treat moisture pickup as a real process-control issue, not an optional nicety.

Rod Numbers Beyond Stick: MIG Wire, TIG Filler, and Specialty Alloys

The E7018 logic you have learned does not stop at the electrode holder. Once you move to a MIG gun, a TIG torch, a flux-cored spool or a hardfacing stick, the printing changes shape, but the underlying idea stays the same: a standard classification code that tells you what the metal is, how strong it is and how it behaves in the arc. The difference is that these codes are governed by a different set of AWS specification books, so the digits mean slightly different things.

Start With the Prefix: What E, R and ER Mean

On bare wire, the leading letters tell you how the consumable is used. An E is an electrode, meaning it carries welding current. An R is a rod, meaning it is melted in as filler without carrying current. Most MIG and TIG wires are stamped ER because they can serve both roles: the same ER70S-6 spool runs as an electrode in GMAW and can be cut into lengths and fed by hand as filler in GTAW. Flux-cored wire and stick electrodes keep the plain E prefix because they always carry current. For a full breakdown of how these letters are defined, see the Lincoln Electric AWS classification guide.

The good news is that the first two digits still read the same way as they do on a stick rod: they are the minimum tensile strength of the deposited weld metal in thousands of psi. ER70S-6 has the same 70,000 psi rating as E7018. What follows changes by family.

Mild Steel MIG Wire: ER70S-2, 3, 4, 5 and 6

Here the S simply means solid wire, as opposed to tubular wire. The final digit is a deoxidizer rating, which describes how aggressively the wire cleans up oxygen in the puddle so the weld does not bubble:

• ER70S-1 and ER70S-2 carry aluminum, titanium and silicon deoxidizers, making them a smart choice for clean, killed steels and precision TIG work.
• ER70S-3 uses a moderate silicon-manganese deoxidizer and suits clean sheet metal.
• ER70S-4 has a heavier silicon-manganese package for faster travel speeds on thicker clean plate.
• ER70S-5 is a low-hydrogen, silicon-deoxidized wire for general work.
• ER70S-6 is the most common mild-steel MIG wire in the world. The 6 denotes a high deoxidizer content, so it runs well on rusty, mill-scaled or slightly dirty steel and produces a smooth, attractive bead on butt joints and fillets.

One step up sits ER80S-D2, an 80 ksi low-alloy wire with molybdenum for higher strength and better hot strength. It is the natural match for the alloy steel welding electrodes you would use in stick form on pressure and heavy-equipment work. The D2 suffix is a specific alloy designation, so strength alone does not tell you the chemistry; the suffix does.

Stainless, Aluminum and Nickel Filler Wires

For stainless, the digits stop describing strength and start describing the alloy. ER308L, ER309L and ER316L follow the AWS A5.9 specification for bare wire, where 308, 309 and 316 identify the stainless chemistry being deposited. The L stands for low carbon, capped around 0.03%, which limits carbide precipitation in the heat-affected zone, a problem the industry calls sensitization that can cost a stainless part its corrosion resistance. Choose 308L for 304 stainless, 316L where molybdenum-bearing corrosion resistance matters, and 309L for welding stainless to carbon steel.

Aluminum filler wire follows the same pattern with the alloy number doing the work:

• ER4043 is silicon-based, flows beautifully, resists cracking and is the default for most general aluminum TIG and MIG work, including castings.
• ER5356 is magnesium-based, stronger and harder, and preferred for structural and marine fabrications where strength and anodizing color matter.

Aluminum also punishes dirty base metal more than steel does, so proper aluminum cleaning before welding matters as much as the filler choice. If you are feeding wire through a spool gun or push-pull setup rather than a torch, our aluminum MIG welding guide walks through the setup. On the nickel side, ERNiCu-7 is the classic 70/30 nickel-copper filler for Monel and similar alloys, while cast-iron repair uses trade-style rods such as Ni55 and Ni99, where the number is a nickel content grade rather than a tensile figure.

Flux-Cored Wire, Stainless Stick Rods and Hardfacing

E71T-1 is the workhorse of flux-cored welding, and its digits behave like a hybrid. The T marks tubular wire, 71 indicates a nominal 70 ksi tensile rating, the third digit 1 means all-position capability, and the final digit identifies the flux and shielding type, with T-1 meaning a gas-shielded, fast-freeze tubular wire. It runs in flat and horizontal production work at far higher deposition rates than any stick rod, which is why structural shops lean on it. Our all-position welding rod guide covers where the position limits start to bite.

Stick stainless codes still follow the familiar four-digit skeleton plus chemistry. E308L-16 and E309-16 under the AWS A5.4 classification read as electrode, alloy grade, optional low-carbon letter, then a coating and current digit in which -16 denotes a low-hydrogen iron-powder coating usable on AC or DC. Hardfacing goes further afield entirely: classifications such as FAA-Fe1 or trade numbers like D-1165 describe alloy system and hardness bands under AWS A5.13 and related surfacing standards, because a wear face has no meaningful tensile-strength rating in the E7018 sense.

Common Wire and Filler Codes at a Glance

Code	Process	Alloy	Typical Use
ER70S-6	GMAW / GTAW	Carbon steel, high deoxidizer	General fabrication, rusty or scaled plate
ER70S-2	GMAW / GTAW	Carbon steel, killed steel deoxidizers	Precision TIG, clean sheet and tube
ER80S-D2	GMAW / GTAW	Low-alloy, molybdenum	Higher-strength and pressure work
ER308L	GMAW / GTAW	304 stainless, low carbon	Food, chemical and general stainless
ER309L	GMAW / GTAW	Stainless for dissimilar joints	Steel-to-stainless transitions
ER316L	GMAW / GTAW	316 stainless, low carbon	Marine, coastal and chemical service
ER4043	GMAW / GTAW	Aluminum-silicon	General aluminum, castings, wheels
ER5356	GMAW / GTAW	Aluminum-magnesium	Structural and marine aluminum
ERNiCu-7	GMAW / GTAW	Nickel-copper	Monel and nickel alloy fabrication
E71T-1	FCAW	Carbon steel, tubular	Heavy structural, high deposition
E308L-16	SMAW (stick)	304 stainless, low carbon	Stainless pipe and plate, out of position
FAA-Fe1 / D-1165	SMAW / specialized	Hardfacing alloy	Wear surfaces on earthmoving parts

The pattern to remember is simple: read the prefix first, read the tensile number if there is one, and then read the suffix for chemistry or flux behavior. That habit works on a stick electrode, a MIG spool, a TIG rod and a hardfacing stick alike, and it is exactly what an AWS classification reference is built around.

Choosing the Right Number for the Job: E6010 vs E6011 vs E6013 vs E7018

Knowing how to decode a rod number is only half the battle. The harder question comes at the point of purchase, when you are standing in front of a wall of yellow and blue boxes trying to decide which number actually belongs on the job in front of you. The code tells you what the rod can do. It does not tell you what it should do on your specific joint. That decision comes down to five things: the steel you are welding, the position you are stuck in, the condition of the metal surface, the machine you are running, and whether anyone will be inspecting the result.

The Five Workhorse Rods Side by Side

Most stick welders spend their entire careers on five classifications. Here is how they compare:

Rod	Tensile	Position	Current	Penetration	Slag	Best For	Limitations
E6010	60 ksi	All	DC only (DCEP)	Deep, narrow	Thin, tight	Root passes, open-root pipe, burnt or dirty steel	Spattery, hard to run on AC machines
E6011	60 ksi	All	AC or DC	Deep	Thin	Rusty farm repairs, maintenance, AC buzz boxes	Rougher bead profile, not for cosmetic work
E6013	60 ksi	All	AC or DC	Shallow	Heavy, lifts clean	Sheet metal, thin gauge, beginners, cosmetic passes	Weak against mill scale and contamination
E7018	70 ksi	All	AC or DC (DC preferred)	Moderate	Heavy, smooth	Structural code work, pressure vessels, out-of-position passes	Needs dry storage; must be cleaned of slag before re-welding
E7024	70 ksi	Flat and horizontal only	AC or DC	Moderate	Thick, easy peel	Production fillet welds, heavy plate in a jig	Cannot be used overhead or vertical

The strength figures line up with the AWS classification system published by Lincoln Electric’s AWS classification reference and explained in similar detail by Hobart Brothers’ electrode classification guide.

What Each Rod Is Really For

• E6010 is the root pass rod. Its deep, forceful arc burns through mill scale and cuts into the joint, which is exactly what you want on an open-root pipe weld or a corner joint with a tight fit-up. It runs only on DC electrode positive, so an AC-only machine rules it out.
• E6011 is the farm rod. Same deep penetration as the 6010, but the potassium-rich coating lets it strike and hold an arc on AC, which is what most cheap shop machines output. It will weld over paint, rust and dirt better than any other common rod, though the bead will never win a beauty contest.
• E6013 is the beginner rod. Soft arc, shallow bite, forgiving arc length, and slag that lifts in one piece. It is the right choice for thin sheet and clean flat practice plates, and the wrong choice for anything heavily scaled or structurally loaded. Our All Position Welding Rod Guide goes deeper on where all-position rods fit.
• E7018 is the code rod. Low-hydrogen, 70 ksi, smooth bead, and the electrode most structural drawings actually specify under AWS D1.1. If the paperwork says E7018, nothing else substitutes.
• E7024 is the production rod. Loaded with iron powder, it dumps metal fast in the flat position. A shop running repetitive fillet welds in a fixture can move two to three times faster with a 7024 than with a 7018. Overhead, it simply will not run.

Base Metal Condition Changes Everything

Amperage ranges in the box are starting points, not rules. A 1/8-inch E7018 might run happily at 90–130 amps on clean plate, but the same rod on a chamfered heavy groove needs the upper end. Thinner stock pulls you down. Polarity matters just as much: running a DC-only rod on AC produces an arc that wanders, spatters badly, or refuses to start at all.

Surface condition is the variable beginners underestimate. Heavy mill scale favors E6010 or E6011. Clean, ground steel opens the door to E6013. Galvanizing burns off as toxic white zinc oxide fume and must be ground back before any structural pass. Paint and oil are never acceptable under a code weld.

A Real Scenario: Trailer Frame vs. Code Handrail

Picture two jobs in the same shop. First, a trailer frame has cracked at a gusset. The owner wants it back on the road. There is mill scale, some surface rust, maybe a coat of old paint, and no inspector will ever see it. Grind the crack, open a small V, and run an E6010 root followed by E6011 or E7018 hot passes. Speed and penetration win here, and the repair is sound.

Now the handrail. It is welded to a structural column in a commercial building, and the inspection sheet calls for E7018 to AWS D1.1. This is where rod choice stops being a preference and becomes a compliance requirement. The root must be low-hydrogen, the rod must come from a sealed container or rod oven, and every pass must be cleaned of slag before the next one goes over it. Dropping an E6013 cap over a required E7018 root does not just weaken the joint; it invalidates the weld paperwork and fails inspection.

The practical rule is simple. Read the number, read the drawing, and let the harder of the two decide. For general shop work, a stick welding setup with E6013 and E7018 on hand covers most of what you will meet, and for high-strength or alloyed structures, specialist selections like those covered in Alloy Steel Welding Electrodes apply the same decoding logic to tougher base metals.

Common Mistakes When Reading (and Using) Welding Rod Numbers

Decoding a rod number is only half the job. The rest is avoiding the traps that turn a correctly read code into a rejected weld, a blown-through root pass, or an afternoon spent grinding. Most of the errors below come from welders who learned the digits and skipped the fine print.

The Nine Mistakes That Cost the Most

1. Assuming every 70-series rod is interchangeable. E7018, E7024 and E6010 all hit 70,000 psi tensile strength, but they share little else. E7018 is a low-hydrogen, all-position rod for DCEP or AC; E7024 is an iron-powder, flat-and-horizontal rod that runs hot and fast; E6010 is a deep-penetrating cellulose root rod. Substituting one for another is no shortcut. On code work the inspection sheet names a specific classification, and a matching tensile number does not satisfy it. As Lincoln Electric’s classification guide lays out, coating, current and position are each their own specification.

2. Ignoring the position digit. An E7024 rod is superb on a flat production fillet and useless overhead; the heavy iron-powder coating and high deposition rate will not hold a bead upside down. If your work includes pipe, vertical or overhead, you need a position-1 rod. Our All Position Welding Rod Guide covers which rods qualify and how the position code shows up in welder qualification tests.

3. Running a DC-only rod on an AC machine. E6010 is a straight DCEP rod. Put it on an AC-only buzz box and the alternating polarity blows the arc out every half cycle; it will not strike cleanly, let alone run a bead. E6011 is the AC-compatible alternative in the same family. Check what your machine actually puts out before you buy the box.

4. Using a hydrogen-sensitive rod on rusty or highly restrained joints. Low-hydrogen rods perform best on clean, prepared steel. Welding over rust, oil, paint or heavy mill scale feeds moisture and contaminants into the puddle, and on a restrained, high-strength joint that is a direct path to hydrogen cracking. For dirty or galvanized material, a cellulose rod like E6010 or E6011 punches through better. High-strength alloy steels raise the cracking risk further; see our alloy steel welding electrodes guide for the selection rules.

5. Welding thin sheet with a 6010 root. E6010’s aggressive penetration is an asset on heavy plate and open-root pipe and a liability on 16-gauge sheet, where it burns edges before you can control the puddle. Thin work wants a softer, fast-freeze rod like E6013 at reduced amperage.

6. Thinking a higher number always means a better weld. E11018 on mild A36 plate is not an upgrade. The weld metal is harder, less ductile and more crack-sensitive than the base metal, and the extra strength buys nothing. Match the electrode to the steel, not to the box that impressed you.

7. Ignoring polarity. A rod run on the wrong polarity arcs badly, penetrates wrong and deposits a chemically incorrect weld. The fourth digit tells you what the coating expects; the box confirms it. For a quick refresher on what each digit signals, our advantages of stick welding overview walks through the basics.

8. Not checking lot codes and shelf life. Sealed boxes carry a date; opened boxes age faster. Low-hydrogen coatings absorb moisture from humid shop air within hours out of the container, and that moisture is the leading source of both porosity and hydrogen cracking. Hobart Brothers and other manufacturers publish exposure limits and storage temperatures for exactly this reason.

9. Buying unlabeled loose rods. A coffee can of mystery electrodes has no classification, no lot number and no manufacturer’s drying instructions. You cannot write a welder against a rod you cannot identify, and no inspector will sign off on it.

Quick Troubleshooting: Reading the Weld, Not Just the Box

Symptom	Most Likely Cause	Fix
Porosity in an E7018 bead	Moisture absorbed by the low-hydrogen coating	Re-bake per the manufacturer’s schedule, or discard the rods
Cracks at the toe of a cold joint	Hydrogen pickup plus high restraint	Preheat where required, store rods properly, slow cool
Arc will not strike or keeps going out	Wrong polarity, damp storage, contaminated tip	Switch polarity, use fresh rods, clean the last inch of coating
Rough arc, heavy spatter, mushy bead	Amperage too high, or a rod too large for the plate	Drop 5–10 amps at a time and re-check travel speed
Coating flakes or crumbles	Over-baked in a rod oven or badly handled	Discard per manufacturer guidance — damaged coatings cannot be trusted

The common thread is respect for the specification. A welding rod number is a legal and technical claim, not a marketing label, and the OSHA welding, cutting and brazing standard treats the whole system — electrode, procedure and storage — as a linked safety chain. Read the digits, then honor them.

Storage, Safety, and Code Requirements Behind the Number

A welding rod classification is more than a strength rating. It is a set of handling instructions. For an E7018, that number not only promises 70,000 psi tensile strength and all-position capability, but it also tells you that its flux is moisture-sensitive, needs to stay dry, and may need to be accounted for if an inspector ever asks where it came from.

Moisture, Hydrogen, and Low-Hydrogen Rods

Low-hydrogen electrodes, such as those ending in …15 or …18, get their resistance to hydrogen from a lime-based flux that is manufactured as dry as possible. The downside is that this flux is hygroscopic, meaning it will pull moisture from the air if left exposed. During welding, that moisture dissociates and introduces atomic hydrogen into the puddle. As the weld cools, hydrogen can migrate to stressed points and cause hydrogen embrittlement, creating cracks that can appear days after a weld looked flawless.

To combat this, AWS A5.1 calls for strict control of these electrodes. Exposed low-hydrogen rods are typically held in a heated rod oven between 225–300°F (107–149°C). If they have been left out past their allowable exposure, they may need to be rebaked between 500–800°F (260–430°C) for one to two hours, but only by following the manufacturer’s published schedule. Both Lincoln Electric’s storage and re-drying guidance and ESAB University’s electrode storage article stress that rebaking is a controlled process, not a guess.

Not every rod requires this level of care. Cellulose rods like E6010 and E6011 are not low-hydrogen, though damp flux will still ruin arc quality. On the other hand, high-strength rods such as E8018-G and E11018-M are even more hydrogen-sensitive than E7018. Selection and handling for these can be found in our alloy steel welding electrodes guide.

Exposure Limits and Shop Control

Once opened, a low-hydrogen can starts a clock. Most manufacturers publish a total allowable exposure time for their rods, and after reaching it, exposed electrodes must either be re-dried or discarded. To prevent this, many shops only unseal a small amount at a time, use heated quivers for each welder, and rely on a shop rod oven for bulk storage. On pipe and structural jobs, it’s common for a supervisor to issue rods daily and collect leftovers, ensuring nothing is left to sit in a truck cab overnight.

Codes That Make the Number Binding

The classification isn’t just a recommendation, it’s often a legal requirement. For structural steel, AWS D1.1 requires control of diffusible hydrogen on many joints and recognizes H-suffixes on the classification, such as H4, which means no more than 4 milliliters of diffusible hydrogen per 100 grams of deposited weld metal. For pressure vessels and piping, ASME Section IX ties the electrode classification directly to an approved welding procedure specification (WPS) and the welder’s performance qualification records.

This is exactly why an inspection sheet may demand E7018. The rod on a WPS is a specification, not a suggestion. Swapping it out is not the welder’s decision to make. For more information on which rods fit specific procedures, take a look at our all position welding rod guide.

Fume, PPE, and Exposure Control

The number also gives a hint at what’s coming off of the arc. Every stick electrode produces fume with metallic constituents, such as manganese. Stainless electrodes, like E308L-16 and E309-16, add hexavalent chromium and nickel to that mix. For this reason, NIOSH welding research recommends reducing exposure through ventilation, local exhaust, and respiratory protection when needed.

These controls aren’t optional. OSHA’s welding, cutting, and brazing standards (29 CFR 1910.252 for general industry and 1926.353 for construction) require ventilation sufficient to keep fumes and gases below exposure limits, respiratory protection under a written program when ventilation alone isn’t enough, proper PPE such as a shade-rated helmet, fire-resistant clothing, gloves, safety glasses, and hearing protection, and strict confined-space procedures that include atmospheric testing and mechanical ventilation.

All of these precautions, from heated ovens to sealed storage, are an investment in both code compliance and safety. For help deciding what is worth owning, our Airgas welding supplies guide breaks it down by shop size. At the end of the day, read the number, and respect the number. It tells you not just what the rod will deposit, but exactly how dry it must be to do it safely.

Practical Tips, Quick-Reference Chart, and Conclusion

You now know how to read a welding rod number digit by digit. The last step is turning that knowledge into habit: a chart to keep nearby, a repeatable decoding routine, and the buying and storage habits that keep good rods from going bad before you strike an arc.

The At-a-Glance Rod Chart

If you only print one thing from this article, make it this table. It covers the five stick electrodes you will actually meet in a home shop or production bay.

Rod	Tensile Strength	Position	Current	Penetration	Best For
E6010	60,000 psi	All positions	DC electrode positive	Deep, digging	Root passes, open-root pipe, burnt or dirty plate
E6011	60,000 psi	All positions	AC or DC+	Deep, digging	Farm and field repair on rusty or painted steel
E6013	60,000 psi	All positions	AC, DC- or DC+	Shallow to moderate	Thin sheet, cosmetic work, beginners
E7018	70,000 psi	All positions	DC+	Medium	Structural and code work, low-hydrogen applications
E7024	70,000 psi	Flat and horizontal only	AC or DC+	Medium, high deposition	Fast production fillet and groove welds in the flat position

The current and position columns are exactly why “they are all 70-series” is not a reason to mix rods, and why an all-position rod choice matters once the work leaves the bench.

A Six-Step Routine for Decoding Any Rod

1. Find the classification. It is printed on the paper wrapper or stamped into the flux near the grip end. Bare wire carries it on the reel or spool label.
2. Read the prefix. “E” means a covered arc welding electrode. “R” is a brazing rod, “ER” is bare filler wire for TIG or MIG, and “T” as in E71T-1 signals a tubular flux-cored wire.
3. Decode the tensile digits. Two digits in stick codes (three in five-digit codes such as E11018-M), read in thousands of psi.
4. Decode the position digit. 1 is all positions, 2 is flat and horizontal fillets only, 4 is all positions with a special electrode design.
5. Decode the coating and current digit. This tells you the flux family, which drives penetration, slag behavior, and polarity. Cross-check it against your machine before you buy.
6. Check the suffix and the paperwork. Suffixes such as -H4, -H8, -A1, -A3 or -G modify hydrogen limits and alloy content. Then confirm the whole string against your welding procedure specification or the engineer’s callout sheet.

Buying and Storage Tips That Protect the Number’s Promise

The classification is a guarantee, and it only holds if the rod arrives and stays in spec. Buy sealed packaging rather than loose rods from an open bin, and check the lot or date code on the carton so you can trace it later. Low-hydrogen rods punish careless buying: they are baked and sealed at the factory, and once the seal breaks, the clock starts. As Lincoln Electric outlines in its guidance on storing and redrying electrodes, opened low-hydrogen rods belong in a rod oven or sealed quiver, not on the shelf above a damp garage floor. Our alloy steel welding electrodes guide applies the same handling discipline to high-strength consumables, where hydrogen sensitivity is even less forgiving.

On code work, the WPS legally controls electrode selection, not the operator’s preference. That is a large part of why the AWS Certified Welding Inspector program exists: a CWI checks that the filler metal actually installed matches the governing specification, down to the classification and lot.

A Practice Drill That Builds Real Intuition

Reading charts is useful; feeling the difference is better. Cut a piece of clean mild steel plate, clamp it flat, and run three beads side by side at recommended amperage: one E6013, one E6010, and one E7018. For each, note the arc force, how deep it digs, how the slag peels, and how the finished bead looks. The E6013 will sit proud and shallow, the E6010 will cut a narrow, deep channel, and the E7018 will lie between the two with a glassy, easily lifted slag. One afternoon of that drill teaches more than an hour of chart study, and it pairs well with our broader look at the advantages of stick welding and our best rod for beginners picks.

Safety Reminders Worth Repeating

Whatever rod you load, the basics do not change: a properly rated helmet and shade, flame-resistant clothing, gloves, and ventilation sized to the space. OSHA’s welding, cutting, and brazing standards set the legal floor for fume control and fire prevention, and NIOSH welding guidance adds detail on exposure, especially for stainless and alloy work where hexavalent chromium and nickel are concerns. Store rods in a dry area, keep low-hydrogen consumables heated or sealed, and treat a wet, corroded rod as scrap.

Conclusion: The Number Is a Specification, Not a Label

Every digit stamped on a welding rod is a small contract between the manufacturer, the engineer, and the welder. E7018 promises 70,000 psi minimum tensile strength, all-position capability, and a low-hydrogen coating, and it delivers only when it is stored correctly, run on the right polarity, and applied where the procedure allows. Learn to read the code, check it against the paperwork, and buy, store, and practice with that code in mind, and you will never again burn an afternoon on the wrong rod.

Frequently Asked Questions

What do the numbers on a welding rod mean?

They are an American Welding Society classification code. The letters identify the product type, the first two digits give minimum tensile strength in thousands of psi, the third digit gives welding position, and the fourth digit describes the flux coating and recommended current.

What is the difference between E6013 and E7018?

E6013 has 60,000 psi minimum tensile strength and a titania coating with soft, shallow-penetrating arc, ideal for beginners and sheet metal. E7018 has 70,000 psi strength and is a low-hydrogen iron powder electrode required by most structural codes.

What does the ‘E’ at the start of a welding rod number mean?

E stands for electrode — a consumable coated rod used in arc welding. In filler wire codes such as ER70S-6, the ER prefix means the product can be used as either an electrode or a filler rod.

What does 70 mean in E7018?

It means the deposited weld metal has a specified minimum tensile strength of 70,000 psi (70 ksi, roughly 480 MPa). The accompanying minimum yield strength for E7018 weld metal is typically around 57,000 psi.

What does the third digit in a welding rod number mean?

It is the welding position code. A 1 means the rod can weld flat, horizontal, vertical and overhead; a 2 such as on E7024 means flat and horizontal fillet positions only.

Do I need to store E7018 rods in an oven?

Low-hydrogen rods absorb moisture from the air, so manufacturers recommend heated storage around 225–300°F and re-drying at higher temperatures when exposed. Keeping opened E7018 rods in a sealed container or rod quiver between uses prevents porosity and hydrogen cracking.

Is a higher welding rod number always better?

No. A higher tensile strength rod weld metal is stronger but can be less ductile and more prone to hydrogen cracking in restrained joints. Electrode choice should match the base metal, joint design and the governing welding procedure specification.

Can I use E6011 rods on an AC welder?

Yes — the potassium coating on E6011 lets it run on AC as well as DC, which makes it a good repair rod for farm and outdoor work. By contrast E6010 is DC-only and will not run cleanly on AC.

What does the H4 suffix on a welding rod mean?

H4 is a diffusible hydrogen designation, limiting hydrogen to 4 milliliters per 100 grams of deposited weld metal. H8 and H16 follow the same scale with higher allowed hydrogen.

How do I know which rod my project requires?

On code or structural work the welding procedure specification states the exact AWS classification. For general repair, match the rod to steel type, position, machine polarity and thickness, and when in doubt consult the electrode manufacturer’s selection chart.