Arc Welding Rod Chart: AWS Classifications, Amperage Ranges, and Selection Guide

A welder standing in front of a rack of rod holders often faces the same question: which rod actually belongs on this joint? With dozens of AWS classifications stamped on tiny rod ends, a reliable arc welding rod chart is the difference between a sound weld and a costly rework.

Introduction: Why an Arc Welding Rod Chart Matters

It is a scene that plays out in nearly every fabrication shop and home garage. A welder walks up to the rod rack with a mild steel bracket to join, reads a code stamped on the end of a rod — E7018 — and hesitates. Does that number mean it is strong enough? Is it for flat work only? Can it run on the machine’s AC setting? Ten minutes later, the rod is back on the rack and the search continues, or worse, the wrong rod gets struck on the arc and the weld comes out brittle, cracked, or out of position.

That hesitation is exactly why an arc welding rod chart exists. It is the decoder ring for the alphanumeric classifications stamped on welding consumables, turning a confusing string of letters and numbers into practical information: how strong the weld deposit is, which welding positions the rod supports, what coating or flux covers the core wire, and what current and polarity the rod expects. Within about thirty seconds, a chart tells a welder whether E7018 is the right choice for that bracket — and what to reach for instead when it is not.

What Exactly Is an Arc Welding Rod?

Before the chart makes sense, the term does. In shielded metal arc welding (SMAW), commonly called stick welding, the “rod” is technically a covered electrode: a solid core wire wrapped in a flux coating. When the arc strikes, the coating burns to create shielding gas, forms a protective slag over the molten puddle, and adds alloying elements that fine-tune the mechanical properties of the finished weld. Both the core wire and the coating are engineered as a system, which is why the classification on the side covers more than just the wire itself.

Gas-shielded processes use the same idea in a different form. Gas metal arc welding (GMAW/MIG) feeds a bare or metal-cored wire from a spool, shielded by an external cylinder of gas. Gas tungsten arc welding (GTAW/TIG) uses a non-consumable tungsten electrode to establish the arc while a separate filler rod is fed into the puddle by hand. The rod is still a classified filler metal — it simply is not carrying the current. All of these consumables, stick electrodes and filler wires alike, fall under the classification umbrella of the AWS A5 series of filler metal specifications.

Why the Classification Numbers Exist

The American Welding Society developed its A5 committee structure so that a filler metal’s performance characteristics travel with the product, regardless of manufacturer. Specifications such as AWS A5.1 for carbon steel SMAW electrodes, AWS A5.18 for carbon steel GMAW and GTAW filler metals, and AWS A5.4 for stainless steel covered electrodes each define the same set of things: chemical composition limits, mechanical property requirements (including minimum tensile strength), diffusible hydrogen levels where applicable, approved welding positions, and recommended current conditions. When a rod is classified as E7018 under A5.1, that designation means the manufacturer has certified it meets every requirement the specification attaches to that code.

A chart compresses all of that certification data into readable digits. For carbon steel stick electrodes, the first digits after the “E” identify minimum tensile strength, the third digit identifies welding position, and the final digit identifies coating type, current, and operating characteristics. For gas-shielded wires, the prefix shifts (ER for filler wire, EA for composite electrode) and the digits lean toward chemical composition rather than tensile strength. Understanding these patterns is what separates informed selection from trial and error.

What This Guide Covers

This guide walks through arc welding consumables from the ground up. It explains how the AWS A5 classification systems are structured across carbon steel, low alloy, stainless, aluminum, nickel, copper, and titanium families; how to read a carbon steel arc welding rod chart with SMAW codes like E6010, E6011, E6013, and E7018 as worked examples; and how gas-shielded designations such as ER70S-6 differ from their stick counterparts. From there, it connects rod diameter, amperage windows, welding position, and joint geometry to real selection decisions, covering low hydrogen storage and rod oven requirements alongside the common mistakes that cause porosity, cracking, and hydrogen-induced defects.

Whether the project is a structural fillet weld on mild steel, a repair job requiring an all-position rod, a low alloy steel application demanding controlled chemistry, or aluminum work through GMAW, the selection workflow is the same: identify the base metal, determine the mechanical and service requirements, consult the correct specification, and verify that diameter, amperage, polarity, and storage conditions all align. By the end of this article, the rod rack should stop being intimidating and start being a well-organized library of choices — with the arc welding rod chart as the index.

Understanding AWS Filler Metal Classification Systems

Every arc welding rod chart you tape inside a cabinet door is a compressed translation of one source: the American Welding Society (AWS) A5 series of filler metal specifications. The A5 committee drafts those documents, which are published through AWS Publications and also distributed through the ANSI webstore. A chart cannot show every clause, alloy limit, and test requirement, so it strips a specification down to the handful of digits a welder needs at the machine.

That is why understanding the classification system matters more than memorizing the chart. Once you know how AWS builds a designation, you can decode an unfamiliar code even when no chart is hanging nearby, and you will know which specification to open when the job is unusual.

Who Writes the Rules: The A5 Series Structure

AWS does not publish one giant filler metal standard. Instead, the A5 series is a family of specifications, each scoped to a specific material family and welding process. A few of the anchors you will meet most often:

Specification	What it covers
AWS A5.1	Carbon steel covered electrodes for shielded metal arc welding (stick)
AWS A5.18	Carbon steel electrodes and rods for gas shielded arc welding (GMAW/GTAW)
AWS A5.9	Stainless steel wire, rods, and electrodes
AWS A5.28	Low alloy steel electrodes and rods for gas shielded arc welding
AWS A5.10	Bare aluminum and aluminum alloy electrodes and filler metal
AWS A5.14	Bare nickel and nickel alloy electrodes and filler wires
AWS A5.6 / A5.16	Copper alloy electrodes / titanium and titanium alloy filler metals

So the first move in any chart lookup is really a spec lookup: identify the base metal, then identify the process. Stick electrode for carbon steel sends you to AWS A5.1. A solid MIG wire or TIG rod sends you to AWS A5.18. Stainless bare product sends you to AWS A5.9. Within that specification, the classification code tells you exactly what you are holding.

Reading the Prefix: E, ER, EC, and R

The prefix is the first clue, and it describes product form and process family rather than strength:

• E — an electrode. In practice this usually means a covered stick electrode that carries welding current, though “E” also appears on wires that are part of the circuit, as in GMAW.
• ER — an electrode rod: bare filler supplied as wire or rod. It may or may not carry current depending on the process, so ER70S-6 works as a GMAW wire while an ER-prefixed alloy rod feeds into a GTAW torch.
• EC — a composite electrode, meaning a tubular wire filled with metal powder. Metal-cored and stranded products fall here, and they behave differently from solid wire in terms of deposition rate and arc characteristics.
• R — a plain rod, filler that never becomes part of the electrical circuit. Some specifications use this alone for torch-fed rod.

Letters can also appear after the numbers. A trailing G means some requirements are deliberately unspecified by the manufacturer, which you will see on versatile but less tightly defined wires. Hydrogen suffixes such as H4, H8, and H16 appear on low hydrogen stick electrodes and show up again in the storage discussion later in this article.

Same Skeleton, Different Dialects by Material Family

The structure feels consistent until you cross into a new material family, where the digits change meaning. Carbon steel and low alloy designations encode tensile strength, position, and coating type, which the following sections break down. Aluminum and stainless classifications lean heavily on a registered alloy number instead, so ER4043 and ER5356 under AWS A5.10 point you straight to a chemistry rather than a strength level, exactly the logic covered in our Aluminum MIG Welding: The Complete Practical Guide.

Low alloy steels under AWS A5.28 add an alloy suffix that describes the deposited weld metal chemistry, such as a chromium-molybdenum grade for heat-resistant service, and that family is explored in our Alloy Steel Welding Electrodes: Selection, Use & Safety. Nickel alloys under AWS A5.14 use a registered trade-style designation with a weldability suffix, as you would see selecting filler for an Alloy 20 Welding job. Copper and titanium families follow their own conventions again. The reliable habit is to confirm which specification applies before assuming what a digit means.

System A and System B: The Stainless Wrinkle in A5.9

Stainless steel adds one wrinkle worth knowing. AWS A5.9 classifies stainless wire and rod under two parallel approaches: System A and System B. In simple terms, one system specifies requirements around the chemical composition of the deposited weld metal, while the other specifies requirements around the mechanical properties the weld metal must meet. A product may be listed against one system or both, and the suffix letters can signal additional chemistry distinctions, such as lower carbon or a controlled silicon range.

The practical takeaway: when you read an ER308L-type designation on a stainless chart, check which system the product is described under before comparing it to a test report or a customer requirement. Assuming the two systems are interchangeable is a common source of paperwork trouble on code work.

With the prefixes and specification families sorted, the next step is decoding the numbers themselves, starting with the carbon steel stick electrodes that dominate most arc welding rod charts.

How to Read a Carbon Steel Arc Welding Rod Chart (SMAW Focus)

Most welders meet their first arc welding rod chart at a welding supply counter, staring at a wall of E-numbers and trying to turn them into a rod that will hold a joint together. Once the code makes sense, the chart behaves more like a map than a menu. For shielded metal arc welding (stick welding), everything on it traces back to one specification: AWS A5.1, Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding.

The Four-Part Code Behind Every E-Number

A typical stick electrode classification reads like E7018 or E6013. Each block of characters answers a different question, and a carbon steel arc welding rod chart simply lays those answers out in columns so you can compare rods side by side.

Position in code	What it tells you	E7018 example
“E”	Electrode for arc welding	E
First two or three digits	Minimum tensile strength of deposited weld metal, in ksi	70 = 70,000 psi
Next digit	Welding position usability	1 = all positions
Final digit	Coating type, current/polarity, operating characteristics	8 = low hydrogen iron powder, DC+

The strength digit is the one most people get right without thinking. In E70XX, the “70” means a minimum tensile strength of about 70,000 psi. In the 60-series rods such as E6010, E6011, and E6013, that number drops to 60,000 psi. Read the number, multiply by 1,000, and you have the minimum tensile requirement for the deposited metal.

The third digit controls where you can weld. A “1” means the rod is qualified for all positions — flat, horizontal, vertical, and overhead. A “2” limits you to flat and horizontal fillet welds. That single digit decides whether you can climb a pipe rack or stay at a workbench, so check it first; the All Position Welding Rod Guide goes deeper.

The final digit is the densest part of the code, because it bundles coating type, allowable current and polarity, and puddle behavior into one number. Here is how the common carbon steel rods break down:

• E6010 — high cellulose sodium coating, DC electrode positive only, deep penetration, fast-freeze puddle, ideal for root passes and out-of-position work.
• E6011 — cellulose potassium coating, AC or DC+, similar penetration to 6010 but friendlier on AC machines, a jobsite favorite for dirty or rusty plate.
• E6013 — rutile (titanium dioxide) coating, AC/DC, smooth arc, shallow penetration, soft ripple pattern — the classic beginner and sheet metal rod.
• E7018 — low hydrogen iron powder coating, AC or DC+, high deposition rate, excellent toughness, and the workhorse for structural and pressure vessel work.

Storage and Drying: Where Charts Quietly Matter

A low hydrogen rod that has absorbed moisture is no longer the rod you bought. E7018 and its H-series variants are baked and sealed for a reason: moisture in the coating becomes hydrogen in the arc, and hydrogen in the weld is how you get porosity, cracking, and rejected radiographs. AWS A5.1 addresses this, with annexes covering storage and drying for covered electrodes. Keep packaging sealed until use, hold opened rods in a rod oven at the maker’s recommended temperature, and observe the exposure-time limits the specification and manufacturer publish. For how alloy choices and consumable families differ, see Alloy Steel Welding Electrodes: Selection, Use & Safety.

Amperage Ranges in the Chart

Every serious arc welding rod chart carries an amperage column, and those numbers are not guesses. AWS A5.1 includes annexes listing typical ranges for covered electrodes, tabulated by diameter, welding position, and whether the pass is a root or a cover. A 1/8-inch E7018 commonly runs in the 90–140 amp window, a 5/32-inch rod moves toward roughly 130–180 amps, and 3/32-inch rods for thin material sit lower still. Position shifts the setting: vertical and overhead work usually takes the lower half of the range to keep the puddle from running.

Used properly, the chart connects four decisions in one row: how strong the weld must be, where you can weld it, what current you can run, and how hot the rod wants to be. Read those four columns before you strike an arc, and selection gets considerably simpler.

Gas-Shielded Rods and Wires: Reading ER/EA Classifications

Once you move away from stick welding, the chart changes shape. Gas-shielded processes like GMAW (MIG) and GTAW (TIG) have no flux coating to shield the puddle, so the classification system stops describing coating types and current characteristics and starts describing chemistry and mechanical properties. Read a gas-shielded section of an arc welding rod chart that way, and it stops looking like alphabet soup.

What the Prefixes Mean: E, ER, and EC

The first letters tell you what the consumable is and how it can be used:

• E means electrode. It carries welding current, which applies to GMAW wire feeding through the gun and to flux-cored wire.
• ER means electrode or filler rod. The same consumable can carry current in one process and simply melt into the puddle in another, which is exactly what an ER70S-2 TIG rod is.
• EC means composite electrode, the category for metal-cored and stranded-core wires where a metal sheath is filled with powdered alloy rather than solid metal throughout.

For carbon steel gas-shielded work, the governing document is AWS A5.18, which classifies solid, composite stranded, and metal-cored carbon steel electrodes and rods for GMAW, GTAW, and plasma arc welding. The current revision is available through AWS A5.18/A5.18M-2025. Crucially, A5.18 allows classification on weld metal chemical composition, weld metal mechanical properties, or both, depending on the classification family. A gas-shielded classification may therefore be telling you what the weld metal is made of, what it can withstand, or some combination of the two.

ER70S-2 vs ER70S-6: The Deoxidizer Story

Both are 70 ksi minimum tensile strength solid wires for mild steel, and both work in GMAW and GTAW. S simply means solid. The difference sits in the number behind the S, which indicates the type and amount of deoxidizers present:

Classification	Deoxidation	Best suited for
ER70S-2	Moderate, using aluminum, titanium, and zirconium	Clean, mill-scale-free steel where a smooth, quiet arc and thin sheets matter
ER70S-6	High, with extra silicon and manganese plus aluminum	Mill scale, light rust, and dirty plate; also faster wetting and higher travel speeds
ER70S-G	Manufacturer-defined	General purpose where the filler maker sets the exact chemistry under the “G” catch-all

ER70S-6 is the shop workhorse for exactly this reason. Its extra deoxidizers tolerate the surface contaminants that real-world plate carries, which is why it dominates mild steel MIG work. ER70S-2 earns its place on clean or thin material where puddle control beats contamination tolerance. The ER70S-G category exists for wires whose chemistry doesn’t fit a numbered suffix, so always check the manufacturer’s data sheet before assuming what a G-classified wire will do.

Metal-Cored and Composite Stranded Wires

Metal-cored wires carry an EC classification and consist of a tubular sheath packed with alloy powder. They run on the same feeders as solid wire but deposit metal faster, often produce less spatter than flux-cored, and handle higher currents. They are a logical step up when productivity on fillet and lap welds matters, though they cost more per pound and usually need a tighter gas setup. For alloy work, similar logic applies in alloy steel welding electrode selection, where the suffix after the strength number tells you what the weld metal is alloyed to do.

GTAW Rods vs GMAW Wires: Same ER, Different Job

An ER70S-2 rod used for TIG is bare filler metal dipped into the puddle with no current passing through it. The same alloy fed through a MIG gun carries current and melts at the arc. The classification stays the same; behavior, diameter choice, and handling do not. TIG rods come in short, clean lengths while GMAW wire arrives on a spool, and contamination a TIG rod picks up from a dirty glove shows up as porosity just as surely as it does in MIG.

When Composition Matters More Than Strength

Some families classify almost entirely on chemistry. Aluminum fillers under AWS A5.10 are the clearest example: ER4043 and ER5356 have similar, modest strengths, so you choose by base alloy, service, and corrosion rather than by tensile number. If aluminum gas-shielded welding is your direction, this aluminum MIG welding guide walks through that filler choice in practice.

The pattern repeats across the alloy families. Low alloy GMAW wires under A5.28 use suffixes such as B2 or Ni1 to identify the alloying package, and nickel alloy rods under A5.14 do the same. In every case, read the classification as a summary, then confirm against the official specification, because only the full document defines the required chemistry, testing, and tolerances.

Alloy, Stainless, Aluminum, Nickel, and Other Rod Families

A carbon steel rod covers most everyday jobs, but once the base metal changes, the chart shifts with it. Lay a mild-steel bead on stainless and the seam rusts first. Drag iron or steel into an aluminum puddle and it may look okay but fails later. Each alloy group comes with its own AWS specification, and those specs read differently. Spot the right one and the rest of the chart falls into place.

Low-Alloy Steel Electrodes

Low-alloy rods follow the same start as carbon steel: a leading E followed by digits for minimum tensile strength. The difference is chemistry. Chromium, molybdenum, nickel, and manganese add elevated-temperature strength, creep resistance, or low-temperature toughness. For gas-shielded low-alloy wires, AWS A5.28 applies (AWS A5.28 preview). Stick electrodes in this group fall under the A5.5 section of the same series. Watch the trailing chemistry suffix: ER80S-D2 signals composition as clearly as E7018 signals strength and position. Use these when heat, toughness, or matching a specific alloy steel matters more than simple fill. For more on stick options in this family, see Alloy Steel Welding Electrodes: Selection, Use & Safety.

Stainless: System A and System B

Stainless makes things interesting because AWS A5.9 defines two classification systems for the same product (AWS A5.9 preview). System A is composition-driven: the classification spells out the filler’s nominal chemistry. System B is alloy-type driven: it identifies the stainless family, such as 300-series austenitic or 400-series ferritic, and the spec sets requirements for that type. Most rods carry both, like ER308L or ER316L. The ER prefix means the same code works for GMAW wire or GTAW rod. The 3xx or 4xx number names the alloy family, and a trailing L marks low carbon for better resistance to sensitization.

Stainless stick electrodes follow AWS A5.4. The final two digits show coating and current: -16 runs AC or DCEP, -15 is DC straight polarity, and -25/-26 are the low-hydrogen heavy coatings. Choose stainless when the joint faces food service, chemicals, marine exposure, or any wet environment where carbon steel fails. Corrosion-matched work has extra filler nuances covered in Alloy 20 Welding: Procedures, Filler Metals, and Best Practices.

Aluminum Fillers: Classified by Chemistry

AWS A5.10 covers aluminum alloy solid wires and rods, and the logic is chemical (AWS A5.10 preview). No tensile-strength digit to decode. Read the four-digit AWS aluminum designation directly. ER4043 is silicon-bearing, general-purpose, flows well, and resists cracking. ER5356 is magnesium-bearing, higher strength, and better for structural and marine work. The ER prefix again means it fits torch and wire-feed processes.

Everyday aluminum work ties straight to the chart: Aluminum MIG Welding: The Complete Practical Guide covers wire-fed selection, and Alloy Wheel Welding shows how wheel alloy drives filler choice in repairs.

Nickel, Copper, and Titanium

Three more families complete the group, each with its own naming. Nickel and nickel alloys fall under AWS A5.14 for bare wires and rods, where the base symbol like ERNiCr-3 or ERNiCu-3 names the alloy system (AWS A5.14 preview). Copper alloys sit in AWS A5.6 with short codes such as ECuSi, ECuSn, and ECuAl. Titanium lives in AWS A5.16, where ERTi-1 through ERTi-5 map to commercially pure and alloy grades; shielding gas purity matters more than almost anything else there. The full A5 series is distributed through AWS Publications, and published specs remain the final word.

Family	Governing AWS spec	Classification clue	Reach for it when
Low alloy (gas-shielded)	A5.28	Strength digits plus chemistry suffix	Heat, toughness, or matching alloy steel
Stainless bare wire/rod	A5.9	ER + 3xx/4xx alloy type	Corrosion and clean-service work
Stainless stick electrode	A5.4	E + strength + position + -16/-15	Field stick welding of stainless
Aluminum	A5.10	Four-digit alloy number	Nonferrous, lightweight structures
Nickel alloys	A5.14	ERNi plus alloy system	Aggressive media, high-temperature service
Copper alloys	A5.6	ECu plus compositional code	Conductivity, bronze, marine fittings
Titanium	A5.16	ERTi plus grade number	Chemical, aerospace, oxygen-sensitive parts

Across every row the pattern holds: leading letters identify the process, middle characters identify material or strength, and suffixes describe coating, position, or composition. Read one family and the others only change the vocabulary.

Amperage, Diameter, Position, and Joint Considerations

An arc welding rod chart only becomes useful once you connect three variables that rarely move independently: the diameter in your hand, the position you are welding in, and the amperage window that makes the electrode behave. Set any one of them wrong and the rod fights you, whether it is stubbing, wandering, freezing to the joint, or washing through the plate. That is where most rework starts, so it is worth slowing down here.

Diameter Sets the Amperage Window First

Diameter is the primary driver of current. A thin 1/16 in (1.6 mm) rod simply cannot dissipate the heat that a 5/32 in (4.0 mm) rod can, so the usable amperage range shifts with it. The AWS A5.1 specification for carbon steel stick electrodes includes Annex A.4, which lists typical recommended current ranges for each diameter, polarity, and welding position. Read that annex carefully and you will notice it is labelled as informational guidance rather than a mandatory requirement: a starting recommendation, not a pass/fail limit.

A typical picture for common low hydrogen electrodes looks like this:

Rod Diameter	Typical Amperage Window	Common Positions
1/16 in (1.6 mm)	30–55 A	All-position, thin material, root passes
5/64 in (2.0 mm)	50–80 A	All-position, sheet and light gauge
1/8 in (3.2 mm)	80–130 A	All-position, general fabrication
5/32 in (4.0 mm)	110–165 A	Flat and horizontal primarily
3/16 in (4.8 mm)	140–210 A	Flat, heavy sections

Coating and polarity matter more than beginners expect. A cellulosic 6010 runs hot and digging on DCEP, while a basic 7018 wants steadier, slightly cooler settings and will crackle or leave porosity if dragged too cold. If you want a fuller comparison of how these rods behave in practice, our All Position Welding Rod Guide: Types, Uses & Tips breaks down where each electrode fits.

Position Limits Are Already Written Into the Classification

Before you trust a chart, confirm the rod is even legal for the position you plan to weld. The third digit of an AWS carbon steel classification tells you that: a 1 means all-position capability, a 2 means flat and horizontal only, and a 4 indicates flat, horizontal, and vertical-down. A 7018 (E7018, third digit 1) can run vertical-up on a structural joint; an E7024 is a fast-fill electrode built for flat and horizontal fillets and will sag or undercut if you force it overhead.

Position changes heat input demand, too. Overhead welding requires the lowest practical current for a given diameter so gravity does not pull the puddle out, while a flat butt joint on thick plate can take the upper end of the range. The American Welding Society publishes position qualification guidance alongside the A5 filler metal specifications, and many of the position rules are echoed in code documents such as AWS D1.1 and ASME Section IX.

Joint Geometry and Fit-Up Change Everything

Amperage is not chosen from the rod alone; it is chosen from the rod plus the joint. Consider the differences:

• Butt joint with good fit-up: root gap and land allow full penetration, so you can run toward the middle or lower end of the window.
• Butt joint with a tight or uneven fit-up: add a little current or slow down, or you risk lack of fusion at the root.
• Fillet weld, especially a small leg: too much current washes the toes and creates undercut; drop a size or reduce amps.
• Thin sheet: drop a diameter rather than starving the arc into porosity.
• Heavy, restrained joints: larger diameters and higher amperage in controlled passes prevent cold-lap, but preheat and interpass temperature still govern.

Rod length also quietly affects performance. Long, thin electrodes flex and wander, which is exhausting in out-of-position work, while shorter rods give better control overhead. The same applies to arc length: a tight, consistent arc keeps heat in the joint, while a long arc burns coating, adds spatter, and lets the puddle run ahead of you.

When the Chart Must Give Way to Procedure

Here is the part that matters for anyone welding to code: a chart tells you what is likely to work, but a qualified welding procedure specification (WPS) tells you what is permitted. Prequalified and qualified procedures define essential variables such as process, filler metal classification, diameter range, current range, position, and heat input. Welding outside those ranges without a procedure change is a documentation failure even if the bead looks perfect.

In short: pick the diameter from the joint and position, use Annex A.4 as your starting amperage, adjust by arc sound and bead shape, then confirm everything against your WPS before the work leaves the fixture.

Common Mistakes, Storage, and Troubleshooting

Reading a chart correctly is only half the job. Some of the worst weld failures in the shop come from rods that were classified perfectly on paper but ruined by moisture, mismatched alloy, or a machine set on the wrong polarity. The painful part is that many of these welds look fine on the surface. They pass a visual check, get loaded into service, and then crack.

Moisture: The Quiet Killer of Low Hydrogen Electrodes

The basic-covered electrodes everyone leans on, the E7018 family, earn their toughness from a coating that keeps hydrogen out of the weld pool. That advantage disappears the moment the coating absorbs moisture. Atmospheric humidity is enough. Once the flux goes damp, the arc breaks down the water and drives atomic hydrogen into a cooling weld, where it collects at grain boundaries and stress points and produces hydrogen cracking, sometimes hours after the weld has cooled and the inspector has gone home.

This is why AWS A5.1 treats storage as a specification issue, not a housekeeping suggestion. The storage annex in AWS A5.1/A5.1M lays out the expected handling for low hydrogen electrodes: sealed containers, limited exposure once a package is opened, and rod ovens used to hold or re-dry them. Manufacturers publish recommended drying temperatures and holding times, and those numbers govern. Ovens set too hot will char the coating; ovens set too cool will not drive the moisture out.

Suppliers take storage seriously too, and a reputable welding supply source will keep sealed low hydrogen electrodes in a dry, climate-controlled area rather than on an open shelf. If your distributor stores E7018 cartons next to the loading dock, that is worth asking about before you buy.

Using the Wrong Rod for the Material

Filler metal mismatch is one of the most frequent causes of weldability problems. A rod can be the right strength class and still be wrong for the base metal. Running a mild steel electrode on stainless, using an unmodified 308L filler on a stabilized or high-molybdenum grade, or welding a low alloy pressure vessel with plain carbon filler can all produce welds that look sound and fail mechanically. These defects show up as cracking, poor impact toughness, or accelerated corrosion, and no amount of amperage adjustment fixes a composition problem.

The fix is to match the filler to the base metal and the governing specification. Our alloy steel welding electrodes guide walks through that matching logic for low alloy work, and specialized materials like Alloy 20 have their own filler requirements, covered in our Alloy 20 welding procedures. Aluminum is the classic example of where mismatch gets ignored: filler selection depends on the alloy series, service temperature, and whether the part must stay corrosion resistant. For that, read our aluminum MIG welding guide alongside proper aluminum surface preparation, because contamination is as damaging as a wrong classification.

Misreading the Chart and Setting the Wrong Current

Chart errors usually come from skimming. A welder grabs an E6013 because it was the cheapest box, then wonders why the bead sits on top of the joint instead of tying in. Each classification carries position and current information in its digits, and ignoring it is a choice to fight the rod. Deep-rooted, root-pass work generally wants a penetrating rod such as E6010 or E6011 on direct current, while cap passes and out-of-position work often favor E7018 or E7024 depending on travel speed and joint access. If all-position capability matters to your work, our all-position welding rod guide maps the common choices.

Symptom	Likely Cause	What to Check
Porosity near the surface	Moisture in coating, contaminated base metal, short arc	Oven records, cleaning, arc length
Cracking hours after welding	Hydrogen pickup or wrong filler for the alloy	Low hydrogen storage, classification match
Lack of fusion on root passes	Wrong rod type or too low heat	Amperage window, current type, technique
Excessive spatter, rough bead	Wrong polarity, damp electrode, bad machine settings	DCEN versus DCEP, ground clamp, oven

Classification, Hydrogen, and Mechanical Requirements

Many current specifications allow optional diffusible hydrogen designators and supplementary toughness requirements to be appended to the basic classification. Those suffixes are not decoration. They tell you the weld metal has been tested for hydrogen level and, in some cases, for impact performance at low temperature. When a drawing or procedure calls for a specific hydrogen limit, using a bare-numbered rod is a specification violation even if the tensile strength matches.

Above all, treat any chart as a summary. The published AWS specifications, available through AWS publications and resold through ANSI, remain the source of truth for exact requirements, test values, storage recommendations, and current editions. A quick look at the current spec before the rod reaches the joint takes minutes and prevents the kind of rework that a chart alone never could.

Practical Selection: A Step-By-Step Approach Using an Arc Welding Rod Chart

Reading an arc welding rod chart and choosing the right rod are two different skills. A chart decodes what an electrode is; a selection workflow tells you which chart to open in the first place. Welders who rarely make filler mistakes run the same short sequence every time, whether they are picking a stick rod for a field fillet or a TIG filler for a pressure header.

Step 1: Confirm the Base Metal and the Process

Start with the material, not the rod rack. Verify the base metal grade from a mill test report, heat number, or material marking, and use a positive material identification (PMI) check whenever the paperwork is missing. Carbon steel, low-alloy steel, stainless, aluminum, nickel, and copper each belong to different filler families, and a mismatched alloy is one of the fastest routes to a cracking weld.

Then fix the process, because each one draws from its own AWS A5 specification:

Process	Base metal	AWS spec	Marking
SMAW	Carbon steel	A5.1	E7018
GMAW / GTAW	Carbon steel	A5.18	ER70S-6
SMAW	Low alloy	A5.5	E8018-B2
GMAW / GTAW	Low alloy	A5.28	ER80S-B2
SMAW / GMAW / GTAW	Stainless	A5.4 / A5.9	E308L, ER308L
SMAW / GMAW / GTAW	Aluminum	A5.10	ER5356
GTAW / GMAW	Nickel alloys	A5.14	ERNiCrMo-3

This mapping is not academic. An E7018 is a stick electrode, and the AWS A5.1 specification never shares a classification table with the A5.18 specification that covers gas-shielded carbon steel filler. Weighing whether SMAW still suits the job at hand? Our advantages of stick welding guide covers the trade-offs, while alloy steel welding electrodes digs into the low-alloy side in depth.

Step 2: Write Down the Real Requirements

Before comparing rods, list four things: minimum tensile strength, welding position, service temperature, and the surrounding environment. The last two decide the alloy family. Ambient structural steel rarely needs more than a 70 ksi carbon steel filler; a steam header running at 600 to 900 °F points toward a 1.25Cr-0.5Mo consumable such as E8018-B2; seawater or chemical service points at stainless or duplex; cryogenic duty favors tough 300-series stainless or nickel fillers.

Position matters as much as chemistry. A rod that runs beautifully flat may be unusable overhead, and the third digit in an SMAW classification tells you which positions are permitted. Our all position welding rod guide breaks that down rod by rod.

Step 3: Open the Specification, Not Just the Chart

Charts are summaries; specifications are the authority. Once the process and alloy family are settled, pull the matching AWS A5 document and read two sections: the classification table, which lists the mandatory tensile, yield, and chemistry requirements, and the annex, which offers suggested amperage, polarity, and position guidance. Both AWS Publishing and the ANSI Webstore carry current editions, and revisions genuinely change content, so check the date on the page in front of you.

Step 4: Verify Diameter, Amperage, Polarity, and Storage

With the classification settled, confirm the physical details. Match rod diameter to material thickness and joint position, then set current inside the suggested window for that diameter. Check polarity as well, because E6010 runs only on DCEP while E6013 also accepts AC and DCEN, and the wrong setting can produce porosity or lack of fusion that looks acceptable until it fails. Finally, storage: low-hydrogen electrodes need sealed containers and must be handled according to the exposure and re-baking limits stated in the specification.

Step 5: Test Before You Commit

For anything non-routine, weld a mock-up first: same base metal, thickness, position, and joint geometry as the real work. Inspect it visually, then run the mechanical or NDT checks your code requires. Structural jobs may follow AWS D1.1 while pressure work follows ASME Section IX, and both tie consumable selection back to a qualified procedure. Critical sectors are stricter still, as our aerospace welding guide illustrates.

Three Worked Examples

1. Rusted structural column, field fillet, all positions. A36 steel covered in rust and mill scale: E6011 on AC or DCEP burns through the contamination, and once the joint is cleaned, E7018 delivers the stronger, tougher weld.
2. Boiler header on P11 alloy steel. High-temperature service drives a low-alloy filler, so E8018-B2 under A5.5 is the starting point, with preheat, interpass control, and postweld heat treatment set by the written procedure.
3. 5052-H32 aluminum trailer panel, GMAW. Per the AWS A5.10 chart, ER5356 with 100% argon shielding gives strength and corrosion resistance. Surface prep is half the battle, so pair it with our aluminum MIG welding guide.

Treat selection as a chain rather than a guess: material, process, requirements, specification, consumable details, and a test. Every link has to hold, and a chart only helps when you bring it the right question.

Quick Reference Tables and When to Consult Official Specs

After working through the many classification systems throughout this guide, it’s time to consolidate everything into a usable reference. While a printed or digital arc welding rod chart can save time on the shop floor, it should never be treated as a final authority. The real governing documents will always be the current AWS A5 specifications, as these are the only sources that hold the exact chemical, mechanical, and testing requirements for any filler metal.

Common Carbon Steel SMAW Rods at a Glance

For the vast majority of mild steel fabrication, these are the rods you’ll come across the most. Use this table strictly as a memory aid, as every job will still need to be verified against its applicable code.

Classification	Coating Type	Positions	Common Polarity	Shop Notes
E6010	High cellulose sodium	All-position	DCEP	Deep penetration, excels on dirty or rusty steel.
E6011	High cellulose potassium	All-position	AC or DCEP	A great option for older AC machines with similar traits to E6010.
E6013	Titania potassium	All-position	AC, DCEP, or DCEN	Very forgiving, smooth arc, and ideal for light gauge sheet.
E7018	Low hydrogen iron powder	All-position	DCEP	Strong, ductile, and requires dry storage. Often needed for structural work.

Quick Amperage and Diameter Notes

These ranges are only starting points for common SMAW diameters. Machine type, joint fit-up, position, and technique can all shift them drastically. If you’re looking to run a true all position welding rod, always dial in by test, not by guesswork.

Rod Diameter	E6010/E6011 (Amps)	E6013 (Amps)	E7018 (Amps)
1/16″ (1.6mm)	20 – 40	20 – 40	25 – 40
3/32″ (2.4mm)	40 – 70	40 – 65	70 – 100
1/8″ (3.2mm)	75 – 125	80 – 110	115 – 165
5/32″ (4.0mm)	110 – 165	110 – 140	150 – 215

Decoding Common Abbreviations: E, ER, and R

With so many filler metals on a rack, prefixes are your first clue before ever looking at the digits. This is especially important when branching out from mild steel to more specialized consumables, such as alloy steel welding electrodes.

• E – Stands for Electrode. Primarily used for covered stick electrodes under specs like AWS A5.1 for carbon and low alloy steels.
• ER – Stands for Electrode or Rod. A dual-purpose classification, most often seen for gas-shielded wires and filler rods under specs such as AWS A5.18.
• R – Stands for Rod. Typically a bare filler rod, most commonly used in GTAW or other processes where it isn’t being fed as a consumable electrode.

When to Consult Official Specs

No condensed reference can account for every scenario, so knowing when to pull the source material is just as important as knowing how to read the chart itself. The following rules should be considered non-negotiable in the right circumstances:

• For code-governed work: If your job falls under any code or standard, you must use the current edition of the applicable AWS A5 specification called out by that code. Older charts are not valid substitutes.
• For critical service: Applications involving pressure, impact, low temperature, or severe cyclic loading often require specific mechanical properties, chemistry, and diffusible hydrogen requirements that can only be confirmed through the official spec.
• For uncommon alloys: Stainless, nickel, aluminum, copper, titanium, or highly alloyed steels all have their own A5 specifications with unique rules. A generalized carbon steel chart will not cover any of these families.

At the end of the day, treat any arc welding rod chart as a roadmap to get you pointed in the right direction, however the AWS A5 specifications remain the source of truth. Take the extra minute to consult the current edition, review its annexes, and verify your filler metal to the job at hand. That small step is often the difference between a passable weld, and a fully compliant, sound one.

Conclusion

Nothing magic happens because a rod matches a line in an arc welding rod chart. The chart does one job extremely well: it turns a stamped code like E7018 or ER70S-6 into a set of decisions you can actually make. Strength, position, coating, polarity, and process all sit inside those few characters. Once you can read them, the rack of electrodes in front of you stops being a wall of jargon and starts behaving like a menu.

That decoding skill is the real takeaway from this guide. The first digits tell you the minimum tensile strength the deposited weld metal must reach. The position digit tells you whether the rod will tolerate overhead and vertical work or reward you only in flat and horizontal runs. The final digit describes the covering type, the recommended current and polarity, and the welding characteristics you should expect in the arc. The same habit of reading prefixes applies outside stick welding: ER means filler rod or wire with a required minimum tensile strength, while other designations point to composition-only requirements. Get the prefix right and you have already avoided a bad match before you strike an arc.

What to Carry Back to the Shop

If you remember nothing else from this article, remember these points:

• Identify before you select. Base metal type, thickness, joint position, and service conditions come before rod preference. Carbon steel, low alloy, stainless, aluminum, and nickel families each live in their own AWS A5 specification.
• Match the process. SMAW, GMAW, and GTAW each use different product forms. If you are still deciding whether the stick process fits your work, the advantages of stick welding make a useful case for keeping it in your toolkit.
• Position matters as much as strength. A 70 ksi rod that cannot run overhead will fail you in the wrong joint. The all position welding rod guide breaks down which classifications handle which orientations.
• Alloy work needs alloy thinking. When the base metal is not plain carbon steel, reach for family-specific guidance such as alloy steel welding electrodes rather than assuming a general chart applies.
• Diameter and amperage are a paired decision. Thicker rod, higher current, more penetration, more heat input. Deviate carefully and watch dilution, undercut, and burn-through.
• Surface prep is part of selection. Even the correct filler fails on a contaminated joint, which is why cleaning aluminum before welding matters as much as choosing the right classification.

Where the Chart Ends and the Specification Begins

The most important limitation to accept is this: charts summarize, specifications govern. The AWS A5 series defines the classification, testing, and requirements for each filler metal family, and only the current published version carries authority. Purchase documents, code work, and procedure qualification all reference the specification itself, including its annexes on amperage ranges, diffusible hydrogen levels, and mechanical property requirements. Copies are available through the AWS publications store, and the American Welding Society also publishes supporting educational and certification resources at app.aws.org. For standards that cross into ANSI territory, the ANSI webstore is the usual companion source.

This matters most in regulated work. Pressure vessels, structural steel, and aerospace components do not care what the label on the rod box suggested. They care whether your procedure, your filler lot, and your welder performance qualification line up with the governing code. If you work in that world, resources like the aerospace welding guide show how much further qualification extends beyond a chart lookup.

Selection Is Always a Balance

Good filler metal selection is a balancing act rather than a single answer. You are weighing tensile strength against ductility, position capability against deposition speed, hydrogen control against convenience, and chemistry against service conditions such as corrosion, elevated temperature, or fatigue. A rod that satisfies all four of those at once is the right rod. A rod that satisfies only the strength number is usually the beginning of a rework conversation.

Read the digits honestly, confirm the amperage window for your diameter, store low hydrogen electrodes the way the specification asks, and qualify the procedure when the application demands it. Do that consistently and the arc welding rod chart becomes what it was always meant to be: a fast, reliable bridge between the stamp on the rod and a weld you can stand behind. The chart gives you the answer’s starting point; careful practice, verified against the current AWS A5 specification, is what turns it into a sound joint.

Frequently Asked Questions

What do the numbers in E7018 mean?

E indicates electrode (SMAW). 70 means minimum tensile strength ~70,000 psi. The third/fourth digits relate to welding position and the coating/type (e.g., 1 = all position, 8 = low hydrogen iron powder coating with specific polarity/characteristics). Refer to AWS A5.1 for exact definitions.

What’s the difference between E7018 and ER70S-6?

E7018 is a covered electrode for SMAW (shielded metal arc welding). ER70S-6 is a solid wire/rod for gas-shielded processes like GMAW or GTAW per AWS A5.18. Different processes, forms, and sometimes deoxidizer levels; they are not directly interchangeable without procedure considerations.

How do I choose rod diameter and amperage?

Diameter depends on joint thickness and position. Amperage depends on diameter, coating/classification, polarity, and technique. AWS A5.1 provides typical amperage ranges in annexes as starting points; always follow WPS/procedure or manufacturer recommendations.

Why do low hydrogen rods need special storage?

Low hydrogen coatings can absorb moisture from air, which can introduce hydrogen into the weld and increase risk of cracking. AWS A5.1 and manufacturers recommend storage in rod ovens at specified temperatures/drying cycles to maintain low hydrogen characteristics.

Do I need to follow AWS specifications for hobby welding?

For non-code work, AWS classifications still help you select appropriate filler metal. For code/structural work, you must follow applicable codes and often use qualified procedures/WPS with filler metals meeting the required AWS classification.

Where can I find the official arc welding rod classification tables?

Official tables are in AWS A5 series specifications (e.g., A5.1, A5.18, A5.9, A5.10, A5.14, A5.28) published by the American Welding Society. These are the authoritative primary sources for classification requirements.

What does ER70S-2 vs ER70S-6 mean for GMAW?

Both are AWS A5.18 classifications for gas-shielded carbon steel. ER70S-6 has higher manganese/silicon deoxidizers than ER70S-2, making it more tolerant of light mill scale/rust on cleanable surfaces. Selection depends on base metal condition and shielding gas.

Can I use a stainless rod on mild steel?

Sometimes for dissimilar/joining or specific applications, but it’s not general practice. Different chemistries/mechanical properties and potential for galvanic/corrosion issues. Consult AWS specs and procedure guidance for dissimilar welding.

Are amperage charts on rod boxes always accurate?

Box charts are typical starting recommendations from manufacturers. Actual optimal amperage varies with equipment, cable length, joint fit-up, position, and technique. Treat them as starting points, not absolute values.

How often do AWS A5 specifications change?

AWS A5 specifications are revised periodically (editions/errata). For code work, use the edition referenced by the applicable code. Always consult the current edition for precise classification requirements.