What Do the Numbers on a Welding Rod Mean? A Complete Guide to Reading Electrode Codes (E6010 to E11018-M)

Why Welding Rod Numbers Matter More Than You Think

You’re standing in the aisle at the welding supply shop, holding two rods that look almost identical. One is stamped E6013, the other E7018, and the price tag is nearly the same — but grab the wrong one and your weld can crack, sag, or fail inspection. Those cryptic digits aren’t decoration; they’re a complete spec sheet compressed into four or five characters, and once you can read them, you’ll never guess at the rack again.

Now watch what happens when the numbers get ignored. A hobbyist builds a utility trailer from 1/4-inch steel using E6013 — a rod that runs smoothly, lays a pretty bead, and flatters a beginner. The weld looks fine. A bend test tells the truth: the joint tears open. Swap in correctly stored E7018 on the same joint, same operator, same machine, and it passes cleanly.

The rod didn’t get stronger. The classification changed — and the classification is what the finished steel remembers.

Here’s a scene from a real fabrication shop. An inspector walks the floor, spots a can of electrodes left open overnight, and rejects the entire lot — no argument, no exceptions. Low-hydrogen rods like E7018 pull moisture out of the air, and that moisture becomes hydrogen that can crack a weld hours or even days after it cools. The number on the rod told the inspector it was a low-hydrogen type. The open can told him it wasn’t behaving like one anymore.

That’s why an electrode code is best understood as a legal specification, not a marketing label. Every character is defined by an AWS filler-metal specification. AWS A5.1 covers carbon steel covered electrodes; AWS A5.5 covers low-alloy steel electrodes and adds composition suffixes like -B2 and -M; A5.4, A5.20, and A5.10 handle stainless, flux-cored, and aluminum fillers.

Start with the first letter. An E prefix means the filler metal is an electrode intended for Shielded Metal Arc Welding — stick welding — under the AWS classification system. From there, E6013 packs four separate facts into four digits: minimum tensile strength, welding position, coating chemistry, and acceptable current and polarity. Miss one and you’ve mismatched the rod to the job.

Short Note: The code never tells you the rod’s diameter. Electrodes are supplied in standard sizes — 3/32 in., 1/8 in., 5/32 in., and 3/16 in. — and each diameter carries its own amperage range, which is why the same E7018 can run at 90 amps or 200 amps depending on what’s in the stinger.

That portability and forgiveness is why stick welding remains one of the most widely used processes in maintenance and field work — it works in wind, on rusty steel, and off a generator in a muddy field. It’s also why these numbers matter to such a wide audience: hobbyists and farm repair crews, welding apprentices learning to read a real spec sheet, and structural fabricators who need documented compliance. Different skill levels, same four digits deciding the outcome.

If you’re brand new to the process, start with our beginner’s guide to stick welding before you worry about classifications — getting a stable arc and a clean restart matters more at first than whether your rod is E6013 or E7018. Once your beads are consistent, the numbers become the deciding factor.

This guide walks the whole code, character by character. You’ll learn what each digit means, why the last two digits control coating and current, how the most common rods — E6010, E6011, E6013, E7018, E7024, and E11018-M — actually behave, and how low-hydrogen and impact-toughness suffixes change the rules. You’ll also get the mistakes that trip up even experienced welders, a practical matching guide, and a cheat sheet you can print and keep in the shop.

The Anatomy of an Electrode Code: What Every Digit Actually Means

Every SMAW electrode classification follows one master template, and once you see it, the code stops looking like random numbers. The American Welding Society (AWS) system reads: E + tensile strength + position + coating/current, with an optional suffix tacked on the end. The AWS A5 filler metal standards are the source document behind every stamp you’ll read on a rod.

Here’s the four-digit template — EXXYY — and its five-digit cousin, EXXXYY, broken into pieces.

The “E”: More Than Decoration

The leading E means electrode — a covered, stick-type consumable for shielded metal arc welding. The same logic runs through other filler metals in the Lincoln Electric AWS classification guide, where bare wire carries an ER prefix instead. No E at the front? You’re probably not holding a stick rod.

The Strength Digits: Tensile Strength in ksi

In a four-digit code, the first two digits are the minimum tensile strength of the deposited weld metal, measured in thousands of pounds per square inch — ksi. So the ’60’ in E6013 means 60,000 psi, and the ’70’ in E7018 means 70,000 psi. In metric, that’s roughly 414 MPa and 483 MPa.

In a five-digit code, the rule stretches by one digit: E11018-M carries ‘110’, or 110,000 psi (about 758 MPa). It isn’t a new category — just a higher strength value.

The Position Digit: 1, 2, or 3

The next single digit tells you where the rod can be used.

• 1 — All positions. Flat, horizontal, vertical, and overhead. The most versatile choice.
• 2 — Flat and horizontal fillet welds only. Higher deposition rates, less forgiving out of position.
• 3 — Flat welds only. Once common, now rarely specified.

That’s exactly why E7018 handles up-and-down pipe work while an E7024 stays on flat benches and fillets.

The Final Two Digits: Coating and Current

The last pair identifies the flux coating chemistry and the current the rod is built for. E7018’s ’18’ points to a low-hydrogen, iron-powder coating that runs on AC or DCEP, while E6010’s ’10’ signals a cellulosic coating designed for DCEP only, as outlined in this open welding textbook. These digits change running characteristics and polarity — not strength. We unpack them fully in the next section.

The Optional Suffix

Trailing characters capture what the numeric core can’t, as Hobart Brothers explains in its electrode classification guide: -1 adds improved impact toughness, -H4 caps diffusible hydrogen at 4 ml per 100 g of weld metal, -R signals a moisture-resistant coating, -B2 denotes a specific alloy chemistry, and -M confirms the electrode meets a military or composition requirement.

Digit by Digit: E7018 and E11018-M

E7018: E = electrode. 70 = 70,000 psi minimum tensile strength (483 MPa). 1 = all positions. 18 = low-hydrogen iron-powder coating, AC or DCEP. No suffix.

E11018-M: E = electrode. 110 = 110,000 psi minimum tensile strength (~758 MPa). 1 = all positions. 18 = low-hydrogen iron-powder coating. -M = meets a specified military/composition requirement.

Read left to right and the code never lies. When a suffix is missing from the stamp, don’t assume it isn’t there — check the packaging, because that trailing character can be the difference between a weld that passes inspection and one that doesn’t.

Decoding the Last Two Digits: Coating Chemistry and Welding Current

If the first two or three digits of an electrode code describe what the finished weld is capable of, the last two describe how you’ll actually get there. They tell you what’s baked into the flux coating around the core wire, which welding current the rod needs, and whether the arc will gouge deep into the joint or glide quietly across the surface. It’s the part of the code most welders skim past — and the part that quietly decides whether a rod runs like butter or sputters uselessly on your machine. Learn to read it and you can pick a rod for a job with confidence instead of guesswork.

Under the AWS A5.1 filler metal specification, that final pair works as a two-part label: the first digit sets the coating family and acceptable current, while the second signals position and how much iron powder rides along in the flux. Read the two digits together and you’re reading the rod’s whole personality — how it starts, how it runs, and where it belongs. Here’s the complete lineup.

The Last-Two-Digit Chart for Carbon Steel Electrodes

The “10” suffix is a specialist. Because it requires electrode-positive direct current (DCEP), it won’t run worth a nickel on a buzz box, but its cellulosic coating produces a forceful, digging arc that blows through mill scale and drives deep fusion — exactly what an open-root pipe pass demands. Move to “11” and the coating swaps sodium for potassium, unlocking AC capability while keeping that aggressive cellulosic bite. That polarity flexibility is why E6011 is the go-to repair rod on rusty, painted, or poorly fitted steel.

At the opposite end sits “13.” A rutile-potassium coating gives you a soft, stable, easy-striking arc on AC or either DC polarity, with shallow penetration that makes it forgiving on thin sheet metal. Then there’s “18.” An E7018 carries a low-hydrogen iron-powder coating and runs on AC or DCEP, delivering smooth arc transfer and noticeably higher deposition than an E7016 — which is precisely why it dominates structural work. And “24,” like E7024, is a high-iron-powder rutile electrode limited to flat and horizontal fillet positions, yet it can lay down several times more metal per hour than any all-position rod.

When a Hyphen Changes Everything

Here’s the trap. On a stainless rod like E308L-16, that hyphenated suffix has nothing to do with the A5.1 current table. Under AWS A5.4, the “-15,” “-16,” and “-17” designators describe the stainless coating and its polarity — so a “-15” is a lime-coated, DCEP-only rod, while a “-16” runs on AC or DCEP just like its carbon steel cousins. Hyphens can also flag optional supplemental requirements, such as the hydrogen-controlled E7018-H4 or the improved-impact E7018-1. Read the number, then read the context.

Get this pair wrong and the consequences show up fast: a rod that won’t strike, porosity from a coating never meant for your polarity, or a low-hydrogen weld that cracks months later. The Hobart Brothers electrode classification guide is a solid desk reference, and because coating chemistry also shapes welding fume exposure, matching the suffix to the job protects both the weld and your lungs. When in doubt, check the manufacturer’s data sheet before you strike an arc.

The Common Rods Decoded: E6010, E6011, E6013, E7018, E7024, and E11018-M

Six electrodes cover the vast majority of stick welding in the real world. Here is what each code promises — and where it bites back.

E6010 — The Pipe Root Workhorse

Deep-penetrating, fast-freeze cellulose coating that solidifies almost the instant the arc stops, ideal for open-root pipe work. It runs on DCEP only, so it needs a DC-capable machine or engine drive. A 1/8 in. E6010 runs roughly 70–110 A, according to manufacturer classification charts. The forceful, digging arc blasts through mill scale, rust, and ugly fit-up — exactly why pipe welders reach for it on root passes (see our guide to pipe welding roots). Expect spatter, a whip-and-pause technique, and a rod that will burn a hole straight through thin sheet.

E6011 — The Repair Rod for Dirty Steel

Chemically close to E6010, but the potassium-based coating lets it run on AC or DC — a lifesaver on older AC-only buzz boxes. The deposit matches E6010 at roughly 60,000 psi minimum tensile. It shines on farm repair, rusty gates, and dirty steel where fit-up is rough, penetrates deeply, and starts easily. The trade-offs are heavier spatter, more cleanup, and a coarser bead. Reach for it when the machine is AC-only or the metal hasn’t seen a grinder in years.

E6013 — The Beginner’s All-Rounder

The friendly all-position rod and the standard first spool for new welders. A rutile coating delivers a soft, stable arc, easy restarts, low spatter, and a bead that looks decent even in unsteady hands. It runs on AC or DC, any polarity. The catch is shallow penetration and a deposit of about 60,000 psi, so it suits sheet metal, thin tubing, and non-critical fabrication — not structural joints. Rushing travel speed traps slag and creates inclusions, the classic E6013 failure. A 1/8 in. rod runs about 70–130 A.

E7018 — The Structural Standard

The rod most often named on drawings. The 70 means a minimum 70,000 psi tensile deposit; the 18 signals a low-hydrogen, iron-powder coating that runs on AC or DCEP. Its principal job is minimizing hydrogen-induced cracking in structural and thick-section welds, because trapped hydrogen in a fast-cooling, restrained joint causes cracks. That’s why code work frequently specifies it and why moisture control is non-negotiable. A 1/8 in. E7018 runs about 115–165 A. Keep it in a rod oven — our E7018 storage guide explains re-baking and why a damp rod welds like a bad one.

E7024 — The High-Deposition Drag Rod

An iron-powder rutile rod built for volume. The heavy coating and high current let you literally drag it along the joint, boosting deposition rate and laying a fat, smooth bead in flat and horizontal fillet positions. A 1/8 in. E7024 runs roughly 140–200 A. Penetration is shallow and the puddle is fluid, so only tip it vertical if you enjoy watching metal run down the plate. On thick plate with long, straight fillets, nothing else lays metal faster.

E11018-M — The High-Strength Specialist

A low-hydrogen electrode with a minimum 110,000 psi tensile deposit and controlled alloy chemistry — the “M” denotes military-grade composition requirements. It is specified for quenched-and-tempered high-strength steels such as ASTM A514, where matching strength and low hydrogen are both critical. It runs on DCEP or AC, demands dry storage, and usually requires preheat and interpass control per the welding procedure. Using it on mild steel burns money and adds hydrogen risk with zero strength benefit.

Real-World Scenario: Choosing a Rod for a Trailer Build

Picture a utility trailer built from 1/8 in. mild-steel channel. E6013 will tack and run the thin cross members and side rails beautifully. But the tongue, coupler, spring hangers, and axle brackets are load-bearing, highly restrained, and thick relative to the rest — exactly where hydrogen-induced cracking lives. That’s why the plan calls for E7018: low hydrogen, higher strength, and tolerance for the abuse a trailer frame takes. Use E6013 for fit-up and sheet work, E7018 for anything holding the trailer together.

Codes Beyond Carbon Steel: Low-Alloy, Stainless, Aluminum, and Flux-Cored Numbers

Carbon steel rods are only the entry point. Take a few steps down the same welding aisle and the labels shift—suffixes, extra letters, and alloy numbers that behave nothing like E6013 or E7018. The good news is that the same “compressed spec sheet” thinking still works; you just need to add a few extra rules to your decoding process.

Low-Alloy Electrodes: When the Suffix Steals the Show

Under AWS A5.5, the first four characters still stand for tensile strength, welding position, coating type, and recommended current. The hyphenated suffix is the new piece—and that suffix names the alloy family, not the welding behavior you see on the puddle.

For example, E8018-B2 breaks down as 80,000 psi tensile strength, all-position capability, a low-hydrogen iron-powder coating, and DCEP polarity—plus 1.25% chromium and 0.5% molybdenum for chrome-moly service. Stepping up, E9018-D1 and E10018-D2 deliver higher strength with manganese-molybdenum chemistry. The well-known -M designation (seen on E11018-M) points to that manganese-molybdenum family, usually alloyed with nickel for added toughness. The rule is simple: match the suffix to the base metal, or you risk cracking in service.

Stainless Electrodes: E308L, E309L, E316L

Stainless follows a different rulebook altogether. The three digits identify the alloy family, not strength. E308 is roughly 19% Cr / 9% Ni and is the workhorse for 304-to-304 joints; E309 runs about 23% Cr / 13% Ni and is designed for dissimilar steels and overlays; E316 comes in near 19% Cr / 12% Ni plus molybdenum to boost pitting resistance in corrosive environments.

The letter “L” is the one that often saves welds. It means low carbon—typically 0.03% maximum—which limits carbide precipitation and sensitization, protecting the weld from intergranular corrosion. The trailing two digits describe the coating and polarity: -15 is a lime-type coating intended for DCEP, while -16 and -17 are rutile types that run on AC or DCEP, with -17 usually blended for a smoother arc and easier slag release. Lincoln’s AWS classification breakdown is a handy companion when the rack label gets busy.

One important safety footnote: stainless electrodes generate chromium and nickel fumes. Our stainless filler selection guide pairs nicely with NIOSH welding guidance on proper fume control.

Flux-Cored Wires: The “T” Says Tubular

Flux-cored classifications under AWS A5.20 look confusing until you split them into parts. In E71T-1, “E” means electrode, “7” indicates 70 ksi minimum tensile strength, “1” shows all-position capability, “T” means tubular, and the “-1” suffix defines shielding gas and polarity (commonly CO2 or a mixed gas). E70T-1 uses the same 70 ksi wire, but the “0” as the position digit flags a flat-and-horizontal-only electrode. Self-shielded versions, such as E71T-11, carry no external gas requirement at all.

Aluminum Fillers: ER4043 and ER5356 Are Alloy Names

Aluminum follows AWS A5.10, and the numbers are alloy designations—not strength or position indicators. ER4043 is Al-5Si, roughly 5% silicon, prized for fluidity and common in 6061 work. ER5356 is Al-5Mg, about 5% magnesium, which brings more strength and ductility. The “R” in ER means the filler can be used as a rod or as an electrode, so ER5356 works for both TIG and MIG. For high-magnesium base metals like 5083, higher-magnesium fillers such as ER5183 or ER5556 are usually the safer call.

Read the letters before the digits, then treat the digits as chemistry. Do that consistently, and nothing on the shelf will feel like a mystery anymore.

How the Digits Drive Performance, Safety, and Your Wallet

Every character stamped on an electrode does a job — and that job shows up on your invoice, in your inspection report, and in the air you breathe. Read the code as a performance spec, not a label, and you stop guessing.

Strength Matching: The Cost of Being Wrong

The tensile digits — 60, 70, 80, 90, 100, or 110 — state the minimum as-welded tensile strength in ksi. Under-match and a loaded joint yields before the base metal. Over-match on ductile, low-carbon steel buys nothing but cost, and high-strength codes like E11018-M are less ductile and more sensitive to hydrogen, restraint, and preheat, so they demand tighter fit-up and procedure control. Most matching work on mild steel sits at E70XX — if you can’t explain why you’d jump to E11018-M, don’t.

Position Digits, Slag, and Rework

The final two digits encode coating chemistry, current type, and position capability. A rutile rod like E6013 runs beautifully and climbs vertical-up, but push that thick, glassy slag into a deep overhead groove and you risk trapping it in the bead — a slag inclusion an inspector finds later. Grind out, re-weld, re-inspect: three labor hits from one digit choice. Pick the code for the position you’re welding, and reach for E7018 where slag must lift cleanly and the weld has to pass.

Low-Hydrogen Codes: Cheap Insurance

The 8 in E7018 and the 18 in E11018-M flag a low-hydrogen basic coating. Hydrogen is the enemy of thick-section and high-strength welds: it migrates into the heat-affected zone and causes delayed cracking that can appear days later. But low-hydrogen stays low-hydrogen only if it’s handled right — absorbed moisture from humid shop air reintroduces exactly the hydrogen the coating is designed to exclude, which is why manufacturers specify storage and re-drying, commonly holding electrodes at 250–300°F after opening the can. A rod oven costs far less than a repair.

Iron Powder and Polarity: Where the Money Is

Iron-powder codes such as E7024 pack iron powder into the coating, lifting deposition efficiency well above a standard rutile rod on flat and horizontal work. More metal per hour, fewer electrode changes, and faster travel translate straight into labor savings — the biggest cost in most welding jobs. The catch is position; iron-powder rods are flat-and-horizontal specialists that run poorly out of position. Polarity matters too, because the last digit also sets the current the rod wants: DCEP for E6010, AC or DCEP for E6011, AC or DC for E6013. Wrong polarity gives you arc blow, excess spatter, shallow penetration, and heat where you don’t want it.

The Health Reality Behind Coating Chemistry

The coating that shapes your arc also shapes your fume. Cellulosic coatings like E6010 and E6011 burn off a forceful gas shield and throw more visible fume and spatter than a rutile or basic rod. Stainless electrodes add chromium and nickel to the plume, and that changes the exposure math: according to OSHA, the permissible exposure limit for hexavalent chromium is 5 micrograms per cubic meter of air as an 8-hour time-weighted average, while NIOSH recommends keeping manganese at or below 0.1 mg/m³ as a 10-hour time-weighted average — well below OSHA’s ceiling for manganese fume.

OSHA’s 29 CFR 1910.252 states that welding may produce fumes and gases hazardous to health and requires adequate ventilation and protection, and OSHA’s welding hazard guidance notes that prolonged exposure may cause lung damage and cancers including lung, larynx, and urinary tract cancer. The International Agency for Research on Cancer classifies welding fumes as carcinogenic to humans (Group 1). The controls are simple: keep your head out of the plume, use local exhaust or forced ventilation, and wear respiratory protection when the fume, position, or confined space demands it.

What the Digits Cost You at the Rack

Read together, the digits set four things at once: strength, which decides whether the joint carries its load; position and coating, which decide whether the weld passes; deposition and polarity, which decide what the job costs and how fast you finish; and fume chemistry, which decides what you breathe while you do it. Under-spec and you rework. Over-spec and you pay twice — once at the counter, once in the extra care a stiff, crack-sensitive electrode demands.

Common Mistakes and Myths When Reading Welding Rod Numbers

Reading an electrode code may seem straightforward, but a handful of misconceptions can lead to brittle welds, failed inspections, or wasted time in the shop. While the digits are a compact spec sheet, they do not tell the full story. Knowing what they exclude is just as important as knowing what they mean.

Myths That Lead Welders Astray

One of the most persistent myths is that higher first digits always mean a better rod. The first two (or first three for high-strength alloys) digits indicate minimum tensile strength in thousands of psi, not quality. For thin sheet metal, an E6013 can outperform an E7018 by preventing burn-through, making it far better for that specific task. Similarly, the claim that any rod with a “1” in the third position is the best all-around choice is false. That digit denotes all-position capability, but it says nothing about penetration, slag, or suitability for code work.

Another false assumption is that E7018 and E6013 are interchangeable. Their coatings, hydrogen content, and mechanical properties differ drastically, so swapping them can violate structural requirements. Many also believe the numbers tell you the rod’s diameter, but the AWS classification does not include electrode diameter or amperage range — those appear separately on the package. Pushing a rod above its manufacturer current range causes excess spatter, undercut, and burn-through.

Not all AC-capable rods are equally smooth on AC, either. An electrode designed for stable DC performance can run rougher on alternating current due to its coating chemistry. A final myth to discard is that a rod out of an open can is fine if it looks dry. Low-hydrogen electrodes, such as E7018, are hygroscopic and can absorb moisture in minutes, drastically raising diffusible hydrogen levels. This is one of the leading causes of delayed cracking in thick or restrained joints.

Costly Mistakes in the Field

While myths spread misinformation, avoidable mistakes cost jobs. Running E7018 without a rod oven or with a contaminated coating is perhaps the most frequent error. For high-strength applications, codes often require storage in heated ovens to maintain the low-hydrogen designation. Using E6013 for structural code work can be equally problematic, as many specifications prohibit its use for critical, load-bearing welds.

Welders can also confuse overmatching base metal strength with success. Overmatching can reduce ductility in the joint and create stress concentrations, so undermatching for ductility is sometimes the correct choice. Misreading a five-digit code as a four-digit code (for example, overlooking the final characters in low-alloy classifications) can lead to mismatched chemistry. Treating the coating and current digits as a serial number, or ignoring the -H4/-R suffixes, strips away critical compliance data.

Polarity errors are equally damaging. Reversing polarity on a DC-only rod such as E6010 produces an unstable, sputtering arc and poor penetration. Always verify polarity against the manufacturer’s recommendations and the classification details outlined by the AWS filler metal standards program before striking an arc.

Perhaps the most sobering lesson comes from a repair shop scenario: tasked with repairing a high-carbon shaft, they opted for E6011 as a quick fix. The deep-penetrating, fast-freeze rod introduced extreme restraint and a hard, brittle heat-affected zone, resulting in cracking under load. It was not a bad electrode, but it was the wrong electrode for that metallurgy — a textbook “doctor’s error” of convenience over compatibility.

Above all, assuming one code fits every joint is the greatest mistake of all. Electrode selection is a trade-off, not a competition. By debunking these myths and correcting these errors, you will not only protect your welds, but you will also uphold the safety standards set by OSHA and the best practices tracked by the NIOSH Welding Program for the job at hand.

Practical Tips: How to Match a Welding Rod Number to the Job

Reading an electrode code is one skill. Choosing the right number for a specific job is the skill that keeps inspectors happy and rework off your schedule. Run this six-step routine every time you reach for a rod.

Step-by-Step: From Base Metal to Machine Setting

Why the order matters. Welders often grab a rod by habit, then fight the machine settings afterward. Working base metal, then strength, then position, then coating, then polarity, then storage means each choice narrows the next — and you rarely arrive at the torch holding the wrong rod.

Step 1 — Identify the base metal. Mild steel, low-alloy or high-strength steel, stainless, cast iron, and aluminum each live in their own code family: carbon steel electrodes under AWS A5.1, low-alloy under A5.5, stainless under A5.4. Knowing the family narrows your rack before you look at a single digit, as the AWS filler metal specifications show.

Step 2 — Match strength and toughness. Match deposited weld metal tensile strength to the base metal, avoiding significant undermatching and avoiding overmatching above roughly 70 ksi on mild steel. Then ask whether the code or your procedure requires impact toughness — that answer pushes you toward a low-hydrogen E7018 or E11018-M rather than a cellulosic rod.

Step 3 — Choose the position digit. The third digit is your geometry guide: 1 for all-position, 2 for flat and horizontal fillets, 4 for flat only. Weld overhead with an E7024 iron-powder rod and gravity will hand you back a puddle.

Step 4 — Pick coating and current to match conditions. Cellulosic E6011 digs through rust, mill scale, and light contamination in field repairs. Low-hydrogen E7018 lays tough, crack-resistant structural deposits. Iron-powder E7024 puts down metal fast on flat production. Conditions first, machine second.

Step 5 — Confirm polarity and amperage. The same digits that describe the coating dictate polarity: E6010 runs on DC+, E6011 on AC or DC+, E7018 on DC+ or AC. Dial amperage from a classification-specific chart, because a 1/8 in. rod can span roughly 70–165 A depending on the code.

Step 6 — Check storage and re-drying. Low-hydrogen electrodes absorb moisture, which brings porosity and underbead cracking. Hold E7018 in a 250–300°F oven, re-dry per the manufacturer’s data sheet, and keep rods sealed until the moment of use — the Hobart electrode classification guide is a handy reference.

Worked Examples: Four Jobs, Four Rods

Reading the table. The trailer frame and the pipe root both want cellulosic electrodes, but for different reasons — contamination tolerance for the repair, fast-freezing behaviour for the open root. The dairy tank demands cleanliness and a matching stainless classification. The heavy plate trades position flexibility for deposition rate.

Shop Tips That Prevent Rework

• Keep a laminated comparison chart at the rod rack, sorted by classification, position, and polarity.
• Mark every rod oven with the classification it holds and its holding temperature.
• Use the smallest practical diameter on sheet metal — thin plate overheats fast, and a 3/32 in. E6013 beats a 1/8 in. rod for burn-through control.
• Store each classification in its own sealed container; a stray E6010 among E7018 rods means moisture pickup and a surprise on the next structural weld.
• Check manufacturer data sheets for re-drying temperatures before you bake a batch, and log oven temperature daily.
• Rotate stock first-in, first-out — older rods deteriorate in humid shops.

Electrode Code Cheat Sheet, Comparison and Final Takeaways

After learning what each digit stands for, the rack at your local welding supply stops looking random and starts looking like a blueprint. With so many options to choose from, having a quick reference can mean the difference between a solid weld and a costly rework. Below is a compact rundown for the rods you’ll see most often, pulled directly from the core AWS A5 filler metal classifications that cover carbon steel, stainless steel, and common nonferrous electrodes.

The Go-To Electrode Cheat Sheet

Quick Comparisons for Common Confusions

E6013 vs E7018: E6013 is forgiving, runs exceptionally well on AC, and suits sheet metal or hobby repairs. E7018, on the other hand, is a low-hydrogen rod with higher tensile strength, making it the go-to for structural work under AWS D1.1. The tradeoff is storage: 7018 demands a dry rod oven and typically performs best on DC+.

E6010 vs E6011: Both are deep-penetrating, all-position rods built for getting into tight joints. E6010 runs strictly on DC+ and excels at root passes, especially on pipe. E6011 is nearly identical in its performance, but its potassium coating allows for AC operation, making it ideal when your machine lacks DC output or you’re working with older equipment.

E7018 vs E7024: Strength is equal at 70 ksi, but position is what splits these two apart. E7018 covers all positions, from overhead to vertical, while E7024 is limited to flat and horizontal (position “2”). In return for this limitation, E7024 lays down a tremendous amount of metal at a faster pace, perfect for large flat fillets where productivity matters most.

The Master Rule and Search Intent

With that breakdown in mind, the answer to the most common search intent is simple: the numbers represent strength, position, coating, and current — nothing more mysterious than that. As a quick sanity check for any rod, you can cross-reference its classification against the Lincoln Electric AWS classification guide or our weldgallery.com filler metal selection hub before ever striking an arc.

Final Takeaways and Action Items

Going back to our opening scenario of the shopper holding E6013 and E7018 in the welding supply aisle, this cheat sheet now allows them to make an educated decision. Instead of guessing based off of name alone, they can read the rack like a spec sheet, matching strength, position, and current to the specific job in a matter of seconds.

To put all of this knowledge into practice, keep these three actions in mind:

1. Write the code: Mark the classification clearly on your rod oven or storage bin to ensure low-hydrogen rods stay traceable and dry at all times.
2. Keep this cheat sheet in your toolbox: Reference it on-site for fast, accurate picks without having to scroll through pages on a dirty or gloved screen.
3. Never substitute without checking the WPS: For any code job, confirm the approved classification against your Welding Procedure Specification before changing electrodes under any circumstance.

Frequently Asked Questions

What does the ’60’ or ’70’ in E6010 or E7018 stand for?

It is the minimum tensile strength of the deposited weld metal, expressed in thousands of pounds per square inch (ksi). E6010 deposits weld metal with at least 60,000 psi tensile strength, while E7018 deposits at least 70,000 psi. In metric terms that is roughly 414 MPa and 483 MPa respectively.

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

For a four-digit classification, the third digit tells you which welding positions the electrode is designed for. A ‘1’ means all positions — flat, horizontal, vertical, and overhead — while a ‘2’ restricts the rod to flat and horizontal fillet welds. A ‘3’ (rarely seen today) would indicate flat welding only.

What do the last two digits of an electrode code tell me?

The final two digits describe the flux coating chemistry and the welding current the rod is intended to run on. For example, 10 means a cellulosic sodium coating for DCEP only, 11 means cellulosic potassium for AC or DCEP, 13 means rutile potassium for AC or either DC polarity, and 18 means a low-hydrogen iron-powder coating for AC or DCEP.

Why is E7018 called a low-hydrogen electrode?

Its coating is formulated to minimize the amount of hydrogen that dissolves into the weld pool, which dramatically reduces the risk of hydrogen-induced cracking in thick, restrained, or high-strength joints. That protection only holds if the rods are stored dry and re-dried in a rod oven between roughly 250°F and 300°F after the can is opened.

Is a higher number always a stronger, better welding rod?

No. A higher tensile number only means the deposited metal is stronger, and stronger is not always better — overmatching can make a joint less ductile and less forgiving. The best rod is the one whose strength, position capability, coating, and current match your base metal, joint design, and job specification.

Do the numbers on a welding rod tell me the rod’s diameter?

No. Diameter is printed separately on the package and is usually given in fractions of an inch, such as 3/32 in., 1/8 in., or 5/32 in. Amperage recommendations vary by both classification and diameter, so you need both pieces of information to set your machine correctly.

What do suffixes like -H4, -R, or -1 mean after an electrode code?

They add optional requirements to the basic classification. ‘-H4’ sets a maximum diffusible hydrogen level of 4 ml per 100 g of weld metal, ‘-R’ indicates a moisture-resistant coating, and ‘-1’ indicates improved impact toughness at a lower test temperature. Suffixes never change the strength, position, or coating meaning of the main digits.

Can I use E6013 instead of E7018 on a structural weld?

Generally no. E6013 is a rutile electrode with relatively low penetration and no low-hydrogen guarantee, and it is not typically approved for code structural work on thick or restrained joints. If a Welding Procedure Specification or structural code calls for E7018, substituting E6013 would be a nonconformance.

What do the numbers mean on a stainless rod like E308L-16?

Here the number is an alloy family designation rather than a strength rating. The 308 refers to the stainless alloy chemistry (roughly 19% chromium and 9% nickel), the ‘L’ means low carbon (typically 0.03% maximum) for better corrosion resistance, and the trailing 16 indicates a rutile coating that runs on AC or DCEP. These classifications come from AWS A5.4, not A5.1.

Are welding rod numbers the same across all manufacturers?

Yes — the four- or five-digit classification is defined by American Welding Society filler metal specifications, so an E7018 from one brand meets the same classification requirements as an E7018 from another. Brand matters for coating quality, arc characteristics, and packaging, but the meaning of the numbers themselves is standardized.

Authoritative Sources & Further Reading

• https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.252
• https://www.osha.gov/sites/default/files/publications/OSHA_FS-3647_WELDING.pdf
• https://www.cdc.gov/niosh/welding/about/index.html
• https://www.osha.gov/etools/hospitals/facilities-management/welding-fumes
• https://www.aws.org/standards/page/a5-filler-metals
• https://www.hobartbrothers.com/resources/technical-articles/electrode-classification/
• https://www.lincolnelectric.com/en/welding-and-cutting-resource-center/process-and-theory/aws-classifications
• https://openwa.pressbooks.pub/welding1/chapter/wa8-3/
• https://www.aiha.org/blog/an-insiders-perspective-on-welding-hazards
• https://www.nfpa.org/codes-and-standards