Two welders in protective equipment welding steel

Understanding the Numbers on Welding Rods

If you’re a new welder, there is probably a lot about the process that you’re confused about. After all, there’s just so much to remember, including the different kinds of inert gasses you will be utilizing and all of their interactions with different metals.

You also need to understand how equipment can impact the process, as well. Many different kinds of welding make use of welding rods – also known as welding electrodes – and there are a ton of types of these that you’re likely to see.

The numbers and letters on different welding rods signify quite a few things. These include the tensile strength of each welding electrode, the position that the electrodes can be used in, what kinds of current can be used with that electrode, and what type of electrode coating is used.

Knowing what each of these numbers means and how to recognize them is an essential part of being able to weld properly. Using the wrong type of electrode or using an electrode improperly can lead to all kinds of problems, including damaged welding equipment, ruined metal, and a wasted day – not to mention possible injuries. Let’s learn more about these numbers you’ll see on different welding rods.

Tensile Strength of an Electrode

The second digit or number on an electrode will represent the strength of the welding bead that that material can produce. Tensile strength refers to how much force a material can withstand when pulled or stretched before breaking, cracking, or otherwise incurring damage. Obviously, the tensile strength of a welding rod can play a significant role in the overall effectiveness of the welding process.

This number is typically marked on a welding rod in one or two digits. For example, a welding rod marked with a 70 would indicate that that welding rod can produce a welding bead with a tensile strength of up to 70,000 PSI.

However, you’ll want to be on the lookout for what kind of measurement process your welding rods are utilizing, as tensile strength is sometimes represented in KSI.

Man wearing work gloves pulling welding rods out of box

Welding Position

The second digit shown on a welding rod indicates what welding positions the rod can be placed in. There are four types of welding positions, and an appropriate number represents each.


A couple of different numbers represent welding rods that you can only use in the flat position, depending on the material they are made of. Flat welding is generally considered the easiest type of welding to get involved in since you don’t have to worry about gravity when conducting it.


Horizontal welding positions are also quite friendly to beginners because it’s generally easy to support the welding gun and other equipment you might be utilizing when in this position.


Vertical welding can get a little bit trickier to deal with, especially for beginners, but generally, you’ll get the hang of it with some experience.


You’ll rarely come across a welding rod that can only be utilized in an overhead welding position, but they do exist. Overhead welding is most often done on pieces of base metal that can’t be moved. You’ll often see this welding on the underside of cars and other heavy vehicles.

Box of metal welding rods

Type of Coating

The next number you’ll come across will let you know the electrode coating surrounding the welding rod. This coating is also known as flux, and its essential purpose is to produce a protective atmosphere that will keep oxygen and other gasses out of your weld pool.

When flux coating is burned, it releases gasses such as carbon dioxide, argon, or helium, which will prevent oxidation from occurring during your welding process. The number on the welding rod will tell you precisely what kind of flux you’re working with. This is a must, as different gasses will interact with different metals, well, differently.

You’ll always want to double-check to make sure that you’re using the right kind of flux when doing any type of welding, as choosing to ignore this kind of vital information could lead to a shoddy weld that won’t hold up over time and that’s the absolute last thing that you want to happen.

This digit will also let you know what welding current you can use. With certain types of rods, you can only use an alternating current as opposed to a direct welding current, and vice versa. You’ll always want to check your welding machine to ensure you correctly convert currents during welding.

Chemical Composition

Finally, you will want to check the last digit to find out the chemical composition of your welding rod. This will let you know what kind of metals you can use this welding rod with. The chemical composition you find in your welding rods will affect almost every type of metal you can interact with.

For example, you might not want to use a particular kind of steel, say, cold-pressed steel, with a copper or nickel-based alloy welding rod. If you aren’t entirely sure of what kind of welding rod you’re utilizing, then you aren’t going to want to continue with the welding process.

Understanding the Numbers

Now that we’ve broken down what the numbers on a welding rod mean, we hope you better understand how these welding electrodes work. Any kind of welding can be tough to get into but don’t let your not understanding numbers keep you away from learning how to weld effectively – there’s just no fun in that at all! Good luck with your future welding.

Back to blog