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Welding Rods: A Complete Guide to SMAW Electrodes

 

Shielded Metal Arc Welding (SMAW), commonly known as stick welding, is one of the most versatile and widely used welding processes. At its heart are the **welding rods (electrodes)**—consumable filler materials coated with flux. This guide will walk you through the AWS classification system, the most common rod types, and how to choose the right one for your project.

 

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 What the Numbers Mean: Decoding the AWS Code

 

The American Welding Society (AWS) uses a standardized numbering system printed on every stick electrode. This code tells you everything you need to know about the rod's strength, position, and current requirements.

 

Take the commonly used **E7018** electrode:

 

`E` `70` `1` `8`

 

| Part | Meaning | Example (E7018) |

| :--- | :--- | :--- |

| **E** | **Electrode** (for arc welding). | E |

| **First 2-3 Digits** | **Tensile Strength** in thousands of pounds per square inch (psi) times 1,000. | **70** = 70,000 psi. |

| **Next Digit** | **Welding Position:** <br> • **1** = All positions <br> • **2** = Flat & horizontal only <br> • **4** = Flat, horizontal, vertical down, & overhead. | **1** = Can be used in all positions (except vertical down). |

| **Last Digit(s)** | **Flux Coating & Current Type:** The specific coating composition dictates the arc characteristics, penetration, and compatible power source (AC or DC). | **8** = Low-hydrogen, iron powder coating. Runs on AC or DC+. |

 

### Flux Coating & Current Compatibility Chart

 

Below is a chart detailing common flux coatings and their recommended current types based on the last digit of the AWS classification.

 

| Last Digit(s) | Flux Coating Type | Current Type |

| :--- | :--- | :--- |

| **10** | High cellulose sodium | DC+ (DCEP - Direct Current Electrode Positive) |

| **11** | High cellulose potassium | AC or DC- (DCEN) |

| **12** | High titania sodium | AC or DC- |

| **13** | High titania potassium | AC, DC-, or DC+ |

| **14** | Iron powder, titania | AC, DC-, or DC+ |

| **15** | Low hydrogen sodium | DC+ |

| **16** | Low hydrogen potassium | AC or DC+ |

| **18** | Low hydrogen, iron powder | AC or DC+ |

| **20** | High iron oxide | AC, DC-, or DC+ |

| **24** | Iron powder, titania | AC, DC-, or DC+ |

| **28** | Low hydrogen, iron powder | AC or DC+ |

 

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## Common Welding Rod Types & Their Best Uses

 

Here is a breakdown of the most popular electrodes and their ideal applications.

 

### E6010 (Cellulosic Sodium)

- **Characteristics:** Deep penetrating, "fast-freeze" slag, forceful arc.

- **Current:** DC+ only.

- **Key Uses:** Pipeline welding ("stove-piping"), root passes on pipe, fabrication, and repairs. Excellent for welding through dirt, rust, and paint.

- **Note:** Requires skill to manage the fast-freezing puddle.

 

### E6011 (Cellulosic Potassium)

- **Characteristics:** Very similar to E6010 with deep penetration and a fast-freeze slag.

- **Current:** AC or DC.

- **Key Uses:** The go-to rod for maintenance and repair when only an AC machine is available. Also good for sheet metal and galvanized steel.

 

### E6013 (High Titania Potassium)

- **Characteristics:** Smooth, soft arc with medium penetration. Low spatter and easy to use.

- **Current:** AC or DC.

- **Key Uses:** General-purpose welding on clean, thin sheet metal. An excellent choice for beginners and hobbyists.

 

### E7018 (Low Hydrogen, Iron Powder)

- **Characteristics:** Low-hydrogen formula that produces strong, ductile, crack-resistant welds. Smooth arc and easy slag removal.

- **Current:** AC or DC+ (runs best on DC).

- **Key Uses:** Structural steel, pressure vessels, power generation, and any critical fabrication requiring high strength and toughness.

- **Important:** Requires dry storage. Often labeled H4 or H4R to indicate low moisture content. Must be kept in a rod oven to prevent hydrogen pickup, which causes cracking.

 

### E7014 (Iron Powder, Titania)

- **Characteristics:** High deposition rate, smooth arc, and medium penetration. Contains iron powder which increases welding speed.

- **Current:** AC or DC.

- **Key Uses:** Fast, flat or horizontal welding on thicker materials. Good for general fabrication and structural work where high speed is desired.

 

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## Quick Selection Charts

 

### 1. Electrode Selection by Base Material and Application

 

| Electrode | Base Material & Application | Best Use Case |

| :--- | :--- | :--- |

| **E6010** | Mild steel, pipe, dirty/rusty metal | Root passes, pipeline, deep penetration |

| **E6011** | Mild steel, maintenance, AC-only machines | Repair work on dirty metal, general fabrication |

| **E6013** | Sheet metal, clean mild steel | Beginner practice, thin materials, general purpose |

| **E7014** | Mild steel, flat/horizontal heavy sections | Fast welding, high deposition rate projects |

| **E7018** | Structural steel, pressure vessels, low-temp | Critical welds, high strength, crack resistance |

 

### 2. Electrode Size, Amperage, and Metal Thickness Guide

 

This chart provides a starting point for matching rod diameter and amperage to metal thickness.

 

| Electrode Type | Diameter (in) | Diameter (mm) | Amperage Range | Metal Thickness |

| :--- | :--- | :--- | :--- | :--- |

| **6010/6011** | 3/32" | 2.4 | 40 – 85 A | 3/32" – 3/16" |

| | 1/8" | 3.2 | 75 – 125 A | 1/8" – 1/4" |

| | 5/32" | 4.0 | 110 – 165 A | 1/4" – 3/8" |

| | 3/16" | 4.8 | 140 – 210 A | Over 3/8" |

| **6013** | 1/16" | 1.6 | 20 – 45 A | Up to 1/8" |

| | 3/32" | 2.4 | 40 – 90 A | 3/32" – 3/16" |

| | 1/8" | 3.2 | 80 – 130 A | 1/8" – 1/4" |

| | 5/32" | 4.0 | 105 – 180 A | 1/4" – 3/8" |

| **7014** | 3/32" | 2.4 | 80 – 125 A | 3/32" – 3/16" |

| | 1/8" | 3.2 | 110 – 165 A | 1/8" – 1/4" |

| | 5/32" | 4.0 | 150 – 210 A | 1/4" – 3/8" |

| **7018** | 3/32" | 2.4 | 65 – 100 A | 3/32" – 3/16" |

| | 1/8" | 3.2 | 110 – 165 A | 1/8" – 1/4" |

| | 5/32" | 4.0 | 150 – 220 A | 1/4" – 3/8" |

 

**Note:** Always adjust amperage based on machine power, welding position (decrease for overhead, increase for vertical down), and joint type. Start in the middle of the range and fine-tune.

 

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Essential Tips for Success

 

1.  Match the Metal:

The electrode must be compatible with the base metal and its intended application. Never use a general-purpose rod for critical structural work.

 

2.  Store Electrodes Properly:

This is especially crucial for low-hydrogen rods like E7018, which must be stored in a heated rod oven to prevent moisture absorption. Expired rods can cause weld cracking.

 

3.  Start with a Clean Surface: 

While E6010 and E6011 are forgiving of surface impurities, the best results always come from clean, mill-scale-free metal.

 

4.  Match Size to Thickness:

Using a rod that is too large on thin metal will cause burn-through. Using one that is too small on thick metal will result in a lack of penetration.