Welding rods are a vital part of the welding process. Therefore, choosing the right weld electrode is crucial for creating a clean, strong weld. The primary electrode types used in welding are consumable electrodes and non-consumable ones. However, welding electrodes are also classified depending on their application and type of weld.
Welding is a highly skilled profession and knowing how to weld two pieces of metal to create a stable weld requires expertise. After all, choosing the wrong weld rod can result in a weakened weld. Therefore, one of the first things amateur welders learn is the basic electrode types.
What is a Weld Electrode?
A welding electrode is a metallic steel rod or wire that allows an electrical current to pass through. The electrode creates an electric arc that generates tremendous heat and fuses two pieces of metal. Depending on the welding process, the welding wire can be coated with flux or be bare.
Weld electrodes used in MIG (metal inert gas), flux-cored arc, and stick welding are classed as consumable electrodes. This is because the welding wire melts to form a weld puddle and helps fuse the pieces of metal.
Welding electrodes used in TIG (tungsten inert gas) welding uses a type of non-consumable material that doesn’t melt, usually made from tungsten or carbon. In modern TIG welding, tungsten electrodes are the most common. Welding rods made from carbon are typically used for welding and cutting, however, they are not used as widely
What is the Difference between Electrode and Welding Rod?
A welding electrode and weld rod are the same things. Electrodes and rods create an electric arc and are filler metals to create a strong weld. Some types of MIG welding use a wire feed. So, although this isn’t technically a long rod used in stick welding, the purpose is the same.
Why are Electrodes used in Welding?
Weld electrodes are crucial to the welding process because it carries a continuous electrical current to create the welding arc. When the electrode is pulled away from the metal surface, a small gap forms and electricity flows through that gap. The electric current creates extreme heat to melt both metals, allowing them to fuse together.
Some types of welding electrodes have a shielding gas or flux coating. This shield protects the weld puddle from contamination by atmospheric gases.
In shielded metal arc welding (SMAW or stick welding), the metal welding rod has a coating of flux. As this melts during the welding process, a shielding gas protects the weld bead from contamination. Because electrodes play such a crucial role in the welding process, it is vital to buy high-quality consumables to ensure deep penetration and avoid spatter, poor fusion, and weld cracking.
What are Welding Electrodes made of?
A welding electrode is made from metal and a flux coating. The three most common metal alloys used in manufacturing an electrode are mild steel alloy coated in copper, high carbon steel alloy, and 3-percent nickel steel alloy.
Knowing what the electrode is made from is crucial to ensure a strong weld. The electrode weld rod must have greater tensile strength than the base metals in the weld. In addition, the type of electrode can affect the joint design, welding position, shape, and specifications of the base metals.
What are Basic Electrodes?
The two primary types of welding rods or electrodes are consumable electrodes and non-consumable ones. Typically, consumable electrode types are for MIG, stick, and flux-cored arc welding. Welding with consumables is the most versatile and popular type of welding process.
Consumable Welding Rods
Consumable electrodes melt into the weld pool. Typically, consumables can be a wire feed or a stick electrode. Some MIG welding machines have an automatic wire feed that continually feeds the electrode wire through the welding gun. Stick electrodes are around 14 inches long and come in varying diameters of 1/16 to 5/16 inches.
Consumable electrodes come in two types — coated electrodes and bare electrodes. Coated electrodes can have coatings in varying thicknesses depending on the type of weld. The coatings on consumable electrode rods can be cellulose, minerals, or a mixture of cellulose and minerals.
Bare consumable electrodes are typically only used to weld manganese steel.
Non-consumable Welding Electrodes
The two types of non-consumable electrodes are tungsten electrodes and carbon/graphite electrodes. These basic electrodes are called “non-consumable” because they don’t melt during the weld. When welding with a non-consumable, using a reliable shielding gas is necessary.
It’s good to note that carbon electrode welding is an older form of welding and is rarely used.
Types of Electrodes Used in Welding
Choosing the type of welding rod for the right welding job requires knowing the weld electrode classifications. The American Welding Society (AWS) classifies an individual welding rod by its tensile strength, welding position, and electrode coating type.
Here is a guide to the most common electrodes used in modern welding:
- E6010 electrodes — This electrode type is for DC (direct current) welders for deep penetration welding. They are used for welding metals that are oily, painted, or dirty. Due to their tight arc, they are not for inexperienced welders. They are often used in pipe welding.
- E6011 electrodes — Used with AC (alternating current) welding machines to penetrate deep into metal.
- E6012 electrodes — This popular electrode type is for fast welding, where it’s possible to weld at a horizontal position. Post-weld cleaning is necessary because it tends to leave spatter and slag.
- E6013 electrodes — This electrode type is ideal for welding clean, new sheet metal free from impurities.
- E7014 electrodes — Suitable for high amperage welders, the electrode has shallow penetration and is used for welding low-alloy steel metal.
- E7018 electrodes — One of the easiest welding rods to use, this electrode has a smooth arc that produces minimal splatter. The welds are strong and are suitable for high-impact applications and various types of metals and alloys.
- E7014 electrodes — These electrodes have high-iron content that minimizes splatter. This type of welding rod is suitable for thick steel plate.
Guide to understanding Welding Electrode Classification
When choosing a suitable electrode, it helps to know how they are classified. So, what do the numbers and letters mean?
The first letter, ‘E,’ signifies this is an electrode. The following two digits represent the weld bead’s minimum tensile strength and represent pounds per square inch (psi). The next number is the welding position. And the last one is the coating type.
1/ Welding Electrode Tensile Strength
The first two digits of the welding electrode classification refer to the tensile strength. For example, ‘60’ is a minimum strength of 60,000 psi.
2/ Welding Position
After the first two digits, the next one indicates the position for welding. These are as follows:
- 1 — Flat, horizontal, or vertical position
- 2 — Flat or horizontal position
- 4 — Can be used flat, horizontal, vertically downward position, or overhead position
3/ Welding Rod Coatings
Another consideration when matching the right electrode to the type of weld and metal is the coating and type of current.
Here is the list of coatings the AWS has approved:
- 0 — High cellulose sodium; DC+
- 1 — High cellulose potassium; AC, DC±
- 2 — High titania sodium; AC, DC-
- 3 — High titania potassium; AC, DC±
- 4 — Iron power, titania; AC, DC±
- 5 — Low hydrogen sodium; DC+
- 6 — Low hydrogen potassium; AC, DC±
- 7 — High iron oxide, iron powder; AC, DC±
- 8 — Low hydrogen potassium, iron powder; AC, DC±
What 6 factors are essential when choosing electrodes for your welding
It is crucial to choose the right electrode for the welding job. The factors affecting your decision are the base material, material condition, tensile strength, weld position, service conditions, and current. One or two common electrode types are suitable for most welds in many cases.
Here are the major factors to consider when choosing a welding rod.
1/ Base metal
First, the electrode must be the same as the metals you plan on welding. For example, magnetic metals tend to be alloys or carbon steel. Also, they produce more sparks when you take a grinder to them.
2/ Condition of the base metal
To produce a solid and stable weld, you need to choose the right electrode for the metal’s condition. Very often, welders don’t have the choice of using new, clean steel for the weld. So, it’s vital to check if it’s cast metal or if the metal contains many impurities. This means taking into consideration the penetration of the electrode when choosing one.
3/ Choose an electrode with similar tensile strength
Matching the tensile strength with the base metals is the best way to void cracks appearing in the weld when it cools or is under pressure. For example, an electrode with an AWS classification of E6012 has a tensile strength of 60,000 psi.
4/ Primary welding position
The position of the weld will also influence which type of electrode to choose. For example, horizontal welding or vertical welding requires the correct types of welding rods. Of course, the most common position is welding on a flat surface. However, that is not always possible. Therefore, check the AWS classification to ensure the welding rod can weld at your required position.
5/ Service conditions
You must ensure that the type of electrode you choose will create a weld that will last the service time of the item. For example, will the welded item be used in high heat or low-temperature environments? Will it be subjected to shock loading? If so, you should choose an electrode with low hydrogen and high ductility to prevent weld cracking.
6/ Power source and type of welding current
Finally, the electrode must match the welding current of the welder. So, check to see if you can use the rod with AC, DC, or both types of electrical current.
Welding Rod Types — In Conclusion
Welding rods and electrodes significantly affect weld strength and durability. Therefore, it is crucial to choose the right type of welding rod for your application. Whether you choose a stick rod or welding wire, the electrode must protect the weld puddle from impurities and cool to form a clean, strong weld.