The two main types of welding electrodes are consumable and non-consumable electrodes. When welding two pieces of metal, the electrode helps conduct electricity from the workpiece to fuse two metal pieces.
Consumable electrodes are melted and reduced in size during the welding process. Meanwhile, non-consumable electrodes are more durable and don’t melt off into the parent metals.
Table of Contents
What Is an Electrode?
An electrode in welding is a stick piece of metal attached to your welding machine that creates a current. In turn, this current forms the arc that melts the workpiece.
The arc is identified as the short circuit between the two pieces. This short-circuiting ignites the heat needed for fusion.
In most cases, the electrode piece contains the same kind of metal as the parent metals being fused.
If you are looking for more information about the diameter and sizes of welding rods, then I have written a guide dedicated to this topic.
Consumable electrodes are mainly used in Metal Inert Gas (MIG) and stick welding. These electrodes melt off quickly into your workpiece due to their low melting point.
That being said, consumable electrodes are usually made with nickel and mild steel in their production process. Using this kind of electrode usually involves changing it regularly during welding.
Aside from that consumable electrodes come in bare and coated variations.
Welders don’t regularly use bare electrodes due to their instability. Keeping the arc in check with a bare electrode is often difficult.
Since they’re not very commonplace, you may find people using them to weld manganese steel. Contrastingly, coated electrodes are more user-friendly.
Coated consumable electrodes are available in three different options including light, medium, and heavy-coated electrodes. Let’s dive into the light and heavy options.
Light Coated Electrodes
The lightly sprayed or brushed coat on this kind of electrode helps in reducing impurities during the welding process.
Impurities such as sulfur and oxide tend to reduce a weld’s quality. For this reason, the light coat creates a more evenly melted layer across the parent metal pieces.
In addition to this, a lightly-coated electrode produces little slag compared to heavy-coated electrodes.
Heavy Coated Electrodes
Also referred to as shielded arc electrodes, these heavily coated lengths of metal offer better protection from corrosion.
It creates an effective gas layer that separates the weld zone from the surrounding air. Broadly speaking, when gases like oxygen and nitrogen make contact with hot metal, the workpiece is brittle and unusable.
Additionally, shielded arc electrodes create a more reliable arc that makes the welding process go smoother. Although this type of electrode is heavy on the slag, this byproduct can be useful by withdrawing impurities from the weld such as oxides and sulfur.
Also known as refractory electrodes, non-consumable welding sticks are primarily applied in industry-level work.
Non-consumable electrodes have a substantially high melting point making them last much longer than consumable options.
You can find two different kinds of non-consumable electrodes, namely, carbon and tungsten electrodes.
Carbon or graphite electrodes are commonly used in arc welding and cutting. Carbon arc electrode welding holds lots of benefits.
Some of these include welding thin pieces of metal, more arc control, and you can weld either ferrous or non-ferrous metal.
One of the downsides of using carbon electrodes is that it requires a lot more current compared to metal arc welding. On top of that, some of the carbon material from the electrode can transfer to the weld, which may harden the deposit.
Tungsten electrodes are employed during gas tungsten arc welding. The non-consumable electrode may be fully tungsten-derived.
In other cases, it can be fused with other metals such as zirconium and thorium. In terms of the latter, it usually comes in about 1 to 2% of the electrode components. Meanwhile, a zirconium mix can provide 0.3 to 0.5% of the metal’s content.
You can determine whether a tungsten electrode is made purely of tungsten or not from its painted ends.
If they’re green, the electrode most likely contains 99.5% tungsten. Now, this may not be the best to use when attempting to produce a seamless weld since the electrode has a low carrying capacity.
Consequently, the electrode may get contaminated more easily. For this reason, welders might choose these pure electrodes if the project requires less heat.
Yellow and Red
Yellow-painted ends on the electrode point to a 1% thorium incorporation. In addition to this, red indicates a larger 2% thorium content.
Thorium alloyed tungsten electrodes yield a better welding output due to their lesser contamination levels.
Brown-painted ends specify 0.3 to 0.5% zirconium content present in the tungsten electrode. While not better than thorium-alloyed tungsten electrodes, the zirconium-fused option still outperforms its pure tungsten alternative.
Consumable vs. Non-Consumable Electrodes: Differences and Similarities
After delving into each type of welding electrode, here’s a brief comparison of each type.
The first difference you’ll notice between the electrode types is that the consumable one gets melted in the metal piece. In contrast, the non-consumable one maintains its shape.
Secondly, consumable electrodes act as a filler for any gaps during the welding process. Non-consumable electrodes need extra filler content to fill in the empty spaces.
Thirdly, the choosing process differs. The consumable electrode needs to be a similar metal type to the workpiece. On the other hand, its non-consumable counterpart can be a different kind of metal.
Lastly, non-consumable electrodes can allow you to perform autogenous, homogenous, and heterogenous welding. Nevertheless, consumable electrodes only allow for homogenous and heterogeneous welding. Here’s what each means:
- Autogenous: Using no filler during the fusion process.
- Homogenous: Welding metals using a filler with the same metal characteristics as the parent metals.
- Heterogenous: Fusion by using an external filler with a different metal composition to your workpiece.
When it comes to the similarities, both consumable and non-consumable electrodes emit an arc through conductivity.
Additionally, the electrode types need a shielding gas to protect the weld from external contaminants
Electrode Identification System
The electrode identification system is used by the American Welding Society to identify an electrode’s key specifications easily.
These specifications include the electrode’s tensile strength, welding position, coating type, and other properties like iron powder percentage. Here’s a comprehensive guide on how to read an electrode’s identification.
- The initial “E” stands for electrodes.
- The next two or three digits refer to the electrode’s tensile strength measured in pounds per square inch. Tensile strength is the material’s resistance to being pulled apart.
- The third or fourth digit indicates the electrode’s welding position: 1 means flat, horizontal, overhead, and vertical positions, 2 means flat and horizontal positions, 3 means flat position only, and 4 means horizontal, flat, and vertical positions.
- The fifth digit of the electrode’s identification system points to its coating as well as the used power supply. It can be AC/DC or Direct Current Reverse Polarity (DCRP) vs. Direct Current Straight Polarity (DCSP). This number may also inform you of the electrode’s penetration, whether it’s medium, low, or deep.
Check out the table below for better clarification of powder coating and current identification.
|Digit||Coat Type||Weld Current|
|1||High Cellulose Potassium||AC, DCRP, and DCSP|
|2||High Titania Sodium||AC and DCSP|
|3||High Titania Potassium||AC, DCRP, and DCSP|
|4||Iron Powder Titania||AC, DCRP, and DCSP|
|5||Low Hydrogen Sodium||DCSP|
|6||Low Hydrogen Potassium||AC and DCRP|
|7||High Iron Oxide, Iron Powder||AC and DCSP|
|8||Low Hydrogen Potassium, Iron Powder||AC, DCRP, and DCSP|
After understanding what each digit means, let’s look at a few examples below.
Example #1: E6013
The E6013 electrode has 60,000 psi with a flat, vertical, horizontal, and overhead welding position. The 3 means it has a low hydrogen potassium and iron powder coating with an AC, DCRP, and DCSP current.
Example #2: E4043
In this example, the E4043 electrode utilizes 40,000 psi and has a horizontal, flat, and vertical welding position. Additionally, its coating is composed of titania potassium. Plus, the electrode’s current is powered by AC, DCRP, and DCSP current.
To keep your electrodes in shape, you’ll want to keep them in a dry area. Too much humidity can cause excessive spatters during welding.
If the electrodes are exposed to moisture, you can heat them in the oven for about a couple of hours at 500 degrees F.
Plus, don’t try to bend the electrodes. You may end up ruining the coating, which may lead to an exposed wire. In this case, you’ll need to dispose of the damaged electrode.
Common Welding Electrodes
|E6010||High cellulose sodium||All Positions||DCEP||Deep||60,000 PSI|
|E6011||High cellulose potassium||All Positions||DCEP|
|E6012||High titania sodium||All Positions||DCEP|
|E6013||High titania potassium||All Positions||DCEP|
|E7018||Iron powder low hydrogen||All Positions||DCEP|
|Shallow to Medium||70,000 PSI|
|E7028||Iron powder low hydrogen||Flat Horizontal Fillets||DCEP|
|Shallow to Medium||70,000 PSI|
Whether you’re a welding enthusiast or want to brush up on some knowledge, welding electrodes are a great place to start.
These kinds of electrodes offer two different options, consumable and non-consumable electrodes. The consumable ones are usually eaten up during the welding process.
Non-consumable electrodes retain their shape, but still heat up and reduce in size over a longer period of time.