Welding Rod Types: What Are They and Their Various Uses?
Welding consumables are a factor to consider with welding. Several of the different kinds of welding require the use of consumable welding rods. These welding rods, also known as electrodes, are essential to the production of clean, solid, and finished welds. The trouble is there are many different kinds of welding rods. How do you know which one to pick for your project?
Below, we’ll discuss those rod types and how they can benefit you in your welding projects. Each variety has different uses and benefits, so read on to learn more about them and their applications.
Consumable Vs. Non-Consumable Electrodes
The first important information is learning whether your MIG or TIG setup uses consumable or non-consumable electrodes.
- Generally, processes like stick welding and MIG welding use consumable electrodes.
- TIG welding, in comparison, uses non-consumable electrodes but requires a filler rod in addition to the electrode.
This distinction is vital because most forms of welding have three elements. These three elements are the joined pieces and the filler metal to secure the joint. In these welding processes, the intense heat from the electrical arc melts the metal from both pieces being joined and adds the filler metal to give it more material to fuse into a solid weld.
In stick, MIG, and similar welding processes, the electrode itself is made of the filler material and is melted, often along with flux, into the joint as you weld. In TIG welding, the electrode provides the current, but a secondary rod of filler metal is required to give it additional strength. This filler rod is the consumable part.
Why the Type of Metal is Important
While you can technically grab any old filler rod that fits your welding setup, you must pick the right rod to avoid problems. Choosing the incorrect filler metal leads to all sorts of issues; rusting and corrosion, inclusions and tearing, weakness in the joins or around the weld, or other sources of failure.
Consider an image of a wooden door with a robust deadbolt lock. Breaking through the deadbolt is difficult or impossible, but it would be easy to break the doorframe the lock slots into with sufficient force. So it goes with welding; even picking a strong filler metal doesn’t help if the surrounding metal doesn’t match and breaks under stress.
There are many different kinds of electrodes or filler rods because there are many different materials you may want to join together. Filler rods are most commonly different kinds of steel but can be other metals, including aluminum and bronze, depending on the welder’s needs.
The list goes on and on, but one thing’s for sure: if you don’t know what kind of metal you’re working with, chances are you won’t know what type of welding rod to use yet.
Considerations When Choosing a Welding Rod
There are many factors to consider when picking the correct welding rod for any project.
First, and among the most critical factors, is the materials being joined. As mentioned above, your filler metal needs to match your base materials. Picking the wrong filler will result in everything from burn-through to weakened welds to a non-functional joint.
Second, the position can be significant. Whenever possible, it’s ideal first to rotate the materials, so you’re working on a flat, horizontal surface for welding. If that’s not possible, and you must weld on a vertical or overhead position, certain filler materials won’t work. Instead of pooling and cooling, the materials can drip off the joint and further damage the surface.
Third, there may be external requirements for specific fillers in particular applications. These can come from many sources. For example, industry regulations may specify certain materials used in a given application, either for their chemical or physical properties or for their strength. Welding in construction, for example, needs to be robust for safety reasons, whereas welding for artistic projects may not have any regulations.
Fourth, the shielding gas used for your weld also makes a difference. In particular, various densities of CO2 in your shielding gas can make a significant difference, intended or otherwise. The gas choice is essential because certain gasses react to certain metals, which can compromise the weld if that reaction is present.
All of these must be considered when picking a welding rod because different rods have different properties. So, how do you identify what rod is helpful for what?
Decoding Welding Rod Codes
Welding rods are classified by their properties and are assigned an alphanumeric code. This code is one or two letters followed by four or five numbers. Each has a meaning.
The first code is the letter. Most welding rods start with E, which stands for Electrode, and indicates that the rod is the current-carrying electrode. R means it is a welding rod of filler material but not an electrode. ER means it is both in flux-core or stick welding, where the electrode and the rod are the same (this is a consumable electrode rod.) RB stands for a brazing rod used in brazing rather than welding or usable in both.
Next, you have the first two or three digits of the number. If the number is five digits (such as E10018), then the first three digits are significant. If the total number is four digits long (such as E6010), then the first two digits are meaningful.
These digits specify the capacity or tensile strength of the material and are in kPSI, or thousand pounds per square inch. So the E6010 has 60,000 PSI strength, while the E10018 has 100,000 PSI strength. The most common steel welding rods usually have a 60 or 70.
The following single number will typically be a 1, 2, or 4. This number indicates the position of the material you can use in welding. Remember above we mentioned that the position is essential and that some materials will stay hot for too long and will drip away from overhead or vertical welds. This digit is the number that specifies this information. A “1” indicates that you can use the rod in any position. A “2” shows that you can only use it in flat or horizontal welding, and a “4” means that you can use the rod for flat, horizontal, vertical down, or overhead welding. A “3” would indicate a vertical-only material, but these are not commonly seen.
The final number will be somewhere between 0 and 8 inclusive. This number specifies two things: the coating of the rod (the flux) and what current can be used on it. Sometimes, the last two digits are used instead of just the one.
Here’s an idea of what you might see:
- X0 – High Cellulose Sodium Flux
- X1 – High Cellulose Potassium Flux
- X2 – High Titania Sodium Flux
- X3 – High Titania Potassium Flux
- X4 – Iron Powder and Titania Flux
- X5 – Low Hydrogen Sodium Flux
- X6 – Low Hydrogen Potassium Flux
- X7 – High Iron Oxide, Iron Powder Flux
- X8 – Low Hydrogen Potassium, Iron Powder Flux
- 10 – The same as X0
- 11 – The same as X1
- 22 – High Iron Oxide Flux
- 28 – The same as X8
The content of the flux also determines whether it should be AC, DC+, DC-, or DC±. This information is typically found on the packaging of welding rods and can be found on charts like this.
Another factor you may need to consider is the thickness of the coating of flux on your electrode. This measurement is indicated by a coating factor, which is the ratio of the rod’s diameter and the coating’s diameter. There’s some margin of error, but the three ranges center around these values:
- Light: A coating factor of around 1.25
- Medium: A coating factor of around 1.45
- Heavy: A coating factor of 1.6-2.2.
Light-coated rods offer less shielding gas and are more prone to slag and inclusions. Hence, they are less widely recommended for many applications, particularly those where purity and strength are paramount.
Medium-coated rods are usable in any position and are easier to remove slag than many other types. They are often used in large-scale projects like offshore drilling, pipeline welding, and bridge construction, among other uses. They’re also common for hobbyist applications.
Heavy-coated rods are the most guaranteed to shield a weld and produce superior results. They are used wherever extreme purity is necessary but are overkill in many situations.
Tungsten Electrode Color Codes
Another factor you may encounter is rods coded by color. These are tungsten electrodes that are non-consumable and used in TIG welding.
They come in four primary varieties:
- Green is pure tungsten.
- Yellow is tungsten with around 1% thorium.
- Red is tungsten with around 2% thorium.
- Brown is tungsten with some zirconium percentage, between 0.3% and 5%.
Though, you may see others, such as:
- Light Blue is tungsten with around 0.5% thorium.
- Purple is tungsten with around 3% thorium.
- Orange is tungsten with around 4% thorium.
- White is tungsten with around 0.75% zirconium.
- Black is tungsten with around 1% lanthanum.
- Gold is tungsten with around 1.5% lanthanum.
- Dark Blue is tungsten with around 2% lanthanum.
- Grey is tungsten with around 2% lanthanum.
- Turquoise is a non-standardized tungsten with various mixed oxides.
- Purple is also a non-standardized tungsten with various mixed oxides.
There are also carbon electrodes, but the carbon arc welding process is rarely used today outside of very specific military applications. It is an outdated process that creates more extensive and more difficult-to-control arcs.
The Most Popular Types of Welding Rods
Welding typically follows the 80/20 rule. That is, 80% of your welding will be done using 20% of your rods. In reality, given the vast array of possible niche rods, it’s more like a 99/1 rule. In most arc welding processes, there are typically only about six rods in everyday use.
E6010. Among the most popular electrodes, these require DC and a narrow arc. They are common in steel welding applications that require deep penetration, such as shipbuilding, steel storage tanks, and other large-scale applications.
E6011. These are similar to E6010 but can be used with AC as well. They are one of the most common go-to electrodes for thick welding materials, with a bit more leeway and ease of use than E6010. Their primary drawback is that their weld beads tend to be flatter and leave waves, so they may not be as aesthetically pleasing as other welds.
E6012. These welding rods support both AC and DC current and are ideal for welding with minimal spatter and slag. They create a stable arc and are great at shallow penetration. As such, they are best for repair, cosmetic, non-critical welds, and welds of certain materials like oxidized carbon steel. They also produce thick welds, which may need cleaning after.
E6013. Another of the most popular electrodes, this composition is easy to use and creates very little spatter. It’s commonly used in mid-penetration welding and for mid-thickness materials. It’s also good for short runs and multiple welds, where consistency between welds is necessary during a repositioning.
E7018. Perhaps the most popular electrode, this is one of the best multipurpose rods available and a staple of every welder’s kit. It’s mostly used for welding low and medium-carbon steel and can create a significantly stronger weld than any of the E60XX rods. The flux coating on the rod is also essential for preventing inclusions in the weld itself. E7018 is found in many kinds of construction and other joinery.
E7024. This rod uses a high iron content in its flux, which makes it very quick in heating and deposition. This characteristic makes it ideal for fast, high-speed welds but risks issues if your process is too slow. They’re also ideal for smooth, flat-surfaced, or finely-waved finished welds.
All of this only scratches the surface of electrodes and welding rods. There are many, many other rods out there, many of which have specific purposes. Design specifications, industry regulations, or directives often identify distinct rods necessary for individual projects. Most of this doesn’t need to be memorized, though knowing the basics of how the rods are categorized can give you immediate insight into what you’re working with.
Remember, too, that this is primarily about welding rod electrodes. Filler rods can have other numbers to identify them. For example, aluminum filler rods have numerical codes to specify the aluminum alloy used in the rod so that you can match it as closely as possible to the joined materials.
The rabbit hole is deep, and there’s always more to learn, even among experienced welding veterans. Feel free to contact us with questions about which rods are ideal for your projects or welding equipment requirements. We’re happy to help.