So, you want to know about welding electrodes? Well, I’m not just going to give you a list of names and types. That’s boring! Let me introduce you to the world of welding.
Welding is a great way to create strong bonds between metal objects. However, before welding can occur, the metal needs to be heated up and then cooled off in order for it to become stable enough to weld together. Welders use a variety of tools and techniques when they are working on a project. One tool that many welders use is an electrode or rods made from different metals. In this article, we will discuss the types of electrodes available for welders and their functions.
We will be exploring the types of welding electrodes and in this day and age, there is a huge variety of different options to choose from when shopping for new electrodes. From the type of metal to length and width, many factors can affect your decision about which electrode you should buy.
What are the types of welding electrodes? There are two primary types, consumable and non-consumable. Each type of electrode that is best for one job may not be the best for another. Let’s take a look at some further information and find out which ones might work well on your next project.
Table of Contents
What is a Welding Electrode?
A welding electrode is a metal rod with two different kinds of metal inside. An electrode’s job is to conduct electricity from the welder to the base material. It may come in the form of a metal rod or wire that melts due to the extreme temperatures of welding to connect two pieces of metal. This means being used as a filler rod, which contains a shielding gas and filler material, or it can be covered in flux. We will discuss different types of electrodes in depth further in this article.
What are the different types of Welding Electrodes?
An electrode is required to produce an electric current in a welder’s arc welding process. An electrical current is sent through an electrode while welding, which is used to join the parent metals. When you keep the electrode tip close to the parent metal, an electric current jumps from the electrode tip to the parent metal. The principal aim of welding electrodes is to create an electrical arc. These electrodes can be positively charged or negatively charged as the anode or cathode, respectively.
There are two primary types of welding electrodes, consumables and non-consumables. Consumable electrodes have a strip of filler metal inside them, which gets melted down as the rod is used for welding. It can be reused if the filler were to somehow stay intact. Non-consumable welding rods do not contain any filler material inside them. They are cheaper to use but cannot be reused once they are gone. There are many different types of electrodes within each type that fit specific purposes.
Consumable electrodes are those which turn into liquid metal as the welding process occurs, while non-consumable electrodes remain solid throughout the process.
These types of electrodes are mostly preferred when welding thick pieces of metal because it helps prevent a loss of heat to the backside of the workpiece. This is important when working with metals that require a lot of heat, such as stainless steel or aluminum since failing to deliver enough heat will result in an incomplete fusion between sheets.
For larger structures such as steel tanks, consumable electrodes can also be used for convenience purposes, allowing one worker to control wire feed speed while another focuses on manipulating the torch head and provides protection during welding tasks that involve moving around a lot.
a) Bare Electrodes
Bare electrodes are made from either mild steel or low-alloy steel as a rule. They have better corrosion resistance than high alloy electrodes, so they are typically used for welding structures above ground.
The most common type of bare electrode is the solid wire electrode, which comes in a spool and requires a constant flow of electricity to keep it fed into the weld puddle.
b) Light Coated Electrodes
Light-coated electrodes are bare electrodes with a thin layer of material on them to protect the metal from oxidation during welding. This can be anything from zinc alloys, aluminum, or even cadmium. They have less resistance than bare electrodes and this means more energy is transferred to the rod as opposed to the arc itself.
c) Medium Coated Electrodes
Medium-coated electrodes are bare electrodes with a coating of flux on them, which is usually borax or fluoroborates. This makes the electrode slag formers, where slag is the non-metallic byproduct of welding that comes out as molten glassy particles. The slag then protects the weld from atmospheric gases as it cools to form a crust that is easily removed.
d) Heavy Coated Electrodes or Shielded Arc Electrodes (SAE)
Heavy coated or shielded arc electrodes are bare electrodes with flux on them and an outer casing of copper and steel. This is why they are referred to as ‘coated’ electrodes either way. The outside coating serves two purposes: it helps stop the arc from sputtering at low currents, and it does not allow any flux to be carried out of the weld puddle. Flux inside the electrode protects the molten metal from atmospheric gases and other contaminants that would otherwise adversely affect the weld’s properties.
Non-Consumable rods or wires do not melt during the welding process. Instead, they provide a stable platform for electric conduction and a protective surface to shield weld joints from contamination caused by air or moisture. Note that these can still be used in combination with a consumable electrode to achieve certain things such as mitigating spatter when arc welding.
These electrodes often have more uses in the welding industry than consumables, since they can provide protection for certain types of metal rather than just joining them together. Because they are non-consumable, they are usually ideal for shielding gas applications where constant exposure to intense heat is not an issue.
This includes TIG welding where the electrode itself is used to protect the weld puddle from air and moisture contamination with a flux coating or by applying a shielding gas that does not interact with the particular metal being worked on.
a) Tungsten Electrodes
Tungsten electrodes are essentially thin wires made from tungsten, which is a metal that excels at high temperatures. It is extremely strong and able to withstand high levels of heat. These types of electrodes are used with inert gas (nitrogen) for general welding purposes since they can be heated up quickly and do not melt like other types of electrodes. They usually give the best results when welding thin metal sheets or objects under 1/8th inch thick due to their low tensile strength compared to other electrode types.
They are usually made from tungsten alloyed with either 15 or 30 percent thorium dioxide. This creates a high melting point that allows the metal to be heated to extremely high temperatures without vaporizing within the arc itself.
This is an ideal electrode for welding many different types of metals, including both ferrous and non-ferrous alloys. It also has a very low spatter compared to other types of rod electrodes since it is more easily compressed than metal with a lower melting point.
b) Carbon Electrodes
Carbon or graphite electrodes are used in the welding of carbon and low-alloy steels. They can also provide a stable platform for arc conduction in applications where the molten material is easily displaced such as when spot welding or seam welding.
These electrodes are made from a variety of materials, depending on the precise uses they will be put to in a specific application. Carbon is almost always present in some form, though the proportion can vary widely. In addition, other constituents such as titanium may also be used when welding with high voltage or high amperage applications.
They often take on an oblong shape to allow them to fit into tight spots and form around obstructions that may otherwise cause issues when trying to feed it through a conduit, for example.
What are the precautions while handling welding electrodes?
- Proper protective gear should be worn to avoid any splattering.
- Cautions should be taken while handling welding electrodes because they are always coated with flux.
- To avoid the risk of fire & explosion, make sure there is no flammable gas leakage in the surrounding area.
- Don’t bend the electrodes as it can harm the electrode coating.
- Avoid working in wet conditions because water can cause premature failure of bonding between electrode and coating.
- Avoid working in windy conditions because it may cause splattering & reduce the visibility of the arc.
- Use a gas shield, if necessary, to protect from pollutants and ensure a smooth welding process.
- If the arc is not stable due to improper approach angle, re-position electrodes according to need.
Welding electrodes come in many different shapes and sizes, but they all serve the same basic function of providing a stable platform for welding. There are several types of electrodes available to suit nearly every application and budget. Another important thing to remember is that welding electrodes have a tendency to spatter, so protective clothing and proper eye protection should be used at all times. Now that we understand the different types of electrodes, we can acquire the appropriate electrode for our needs and get to welding.