Welding Rod Chart: Reading the Numbers, Its Analysis, and Functions

Welders can avoid confusion regarding all the different classifications of filler rods, wire, and electrodes. Refer to a welding rod chart or consumables binder as you should. Here is what you need to know to use one properly.

Starting to Read a Welding Rod Chart

Gas tungston arc welding schematic which uses a Welding Rod Chart

Image: CC by A-SA 3.0, Duk, via Wikipedia Commons

Understanding all the different classifications of filler rods, wire, and electrodes used in the welding process appears as one of the bigger challenges for apprentice welders. The number of product lines available daunts them all. So, a mix of classification systems only multiplies that confusion. However, when asked to retrieve or reorder supplies, they feel befuddled.

There comes a way to avoid much of this if you become an apprentice welder. Accordingly, start by learning the industry vernacular, weld symbols, and the jargon used in your employer’s shop. Also, understand what people mean when they ask you to refill the E-7018 rods. Also, take time to understand all the variables that come into play whenever selecting or ordering new consumables.

The Details

Know what object you weld, such as a pipe, and what metal makes up the object. Then, know the size and shape of the groove and any code or structural requirements. Have in mind how the welder approaches the weld, such as from above or below, and the environment.

Moreover, the necessary options such as Hot or cold? Inside or outside? Hence, all of those factors help you choose the right rods to replace. Having a good background of your welding projects comes essentially to the process.

Take Advantage of the Welding Rod Chart

Welder doing Arc welding on metal frames with a wood bases who uses a Welding Rod Chart

Image: CC by A-SA 4.0, Santeri Viinamäki via Wikipedia Commons

Take full advantage of the shop’s welding rod chart or consumables binder.  Notably, an important guide to welding beginners helps you know what to retrieve. Every professional shop has one of these charts or binders. It comes as a searchable digital database in more sophisticated shops.

In there, you find product spec sheets that outline material properties and compliance standards. Subsequently, determined by the American Welding Society, American Society of Mechanical Engineers, and other industry associations.

The Materials

As long as you adhere to the standards set out by these professional organizations, you choose the proper material and consumables that meet the welding code. However, to do that, you need to familiarize yourself with those standards and classifications.

Surprisingly, this helps you when you inevitably encounter different brand names for the same material. Rather than focus on the brand name, know the material classification.  Moreover, you never have to worry about selecting the wrong rod. In this article, we reviewed some of those classifications and what they mean.

Electrode or Filler Rod?

Various Shielded Metal Arc Welding electrodes and an electrode holder which uses Welding Rod Chart as a guide

Image: Public Domain U.S., Triddle, via Wikipedia Commons


At their base level, welding electrodes remain as simply metal wires with a chemical coating added to assist the weld. The rod maintains the welding arc. Also, the filler metal used during the process. Next, the chemical coating further protects the metal, provides some stabilization to the arc, and often helps the welder create a better weld.

Metal Types

The proper way of welding involves choosing the right type of metal for the job. Most likely, you will work with one of the following metals and the rod you select will be of a similar composition:

  • Aluminum
  • Cast iron
  • Mild steel
  • Stainless steel
  • Low-alloy steel

Chemical Additives

The industry categories stick electrodes into four groups, based on chemical additives. These additives protect the weld pool. Additionally, they prevent oxidation and porosity and protect against potential weld defects. Welders also categorize them based on the physical position they find themselves in.

  1. First, the “fast freeze,” denoted by the numbers (0,1) comes useful for welding overhead. The metal in these rods solidifies quickly, avoiding a weld pool shift prior to solidification.
  2. Second, the “Fast fill,” denoted by the code (21-27), for the flat or horizontal position and rarely for anything else. It melts quickly, maximizing welding speed.
  3. Third, “Fill freeze,” with the code (2, 3, 4), comes as an intermediate rod.
  4. Fourth, the “low hydrogen” electrode, noted by the code (18, 28) for limiting porosity.

Know Your Numbers on a Welding Rod Chart

Primarily, one of the first requests you get during your apprenticeship appears in the retrieval of an . Coworkers ask you to fetch a filler rod. In most cases, and specifically in stick welding, they exist the same.

Man Using a couple of filler metal welding rods and to solder the adapters onto that baseuses Welding Rod Chart as a guide

Image: CC by A-SA 2.0, Dennis van Zuijlekom, via Flickr

While going through the welding rod chart, whether it is an old notebook or a laptop computer, you are bound to run into a lot of numbers. As an apprentice, it is your job to learn and understand what these electrode numbers mean.

Know, too, that each number contains a wealth of information. Let’s consider a number like E-7018, a common code, especially in pipe welding.

Here, the letter “E” stands for “electrode,” which is simple enough. The next two digits, 70, indicate the tensile strength of the weld. In this case, 70 equals a minimum tensile strength per square inch of 70,000 pounds.

The Welding Rod Chart Analysis

If the first two numbers were 50, then the tensile strength would be a minimum of 50,000 pounds, and so on. According to some experts, the next two numbers can tell you the most difficult physical position you can be in while welding with the electrode and what flux/deoxidizers are used in the electrode coating.

Therefore, in the number 18, the 1 would represent the position, in this case, “any position,” and the 8 would refer to the flux on the rod. The higher that last number, the better the shielding and the more flux is deposited. It is confusing and antiquated, but you need to know it.

Metal Polarity Readings on a Welding Rod Chart

Welder with helmet Using filler metal welding rodswho uses Welding Rod Chart as a guide

Image: CC 0 by Public Domain, skeeze, via Pixabay

Life would be easy if those numbers were the only classifications any apprentice welder would need to know to select the right material. Maybe that is why there are more classifications out there. If you come across a code with a suffix, such as C1, for example, the number is most likely telling you what additional alloys manufacturers have added to the metal.

You also have to concern yourself with the polarity of the metal. In most welding rod charts, you will encounter one of three different polarity choices. The first, AC, stands for “alternating current” and stands by itself with respect to the electrodes that work best with that polarity. However, the second and third, both DC choices, are a little more complicated.

The Choices

The two choices are DCEP and DCEN. The DC stands for “direct current,” as you may expect. The EP in the first stands for “electrode positive” and the second for “electrode negative.”

Most stick welders use DCEP, also known as “reversed polarity.” The benefit of DCEP is the ability to reverse the current by switching the connections on the electrode holder and work clamp. About 70 percent of the heat generated by the electric arc is used in the welding process, while the other 30 percent is dispersed to the workpiece.

Interestingly enough, DCEN polarity is the opposite. Now 30 percent of the heat is focused on the welding process while 70 percent is dispersed to the workpiece. So when would you use this? Use it when working with thinner metals like aluminum.

Preparing the Welding Rod Chart Final Analysis

Student Tackles Large Welding Project on a welding school who uses Welding Rod Chart as a guide

Image: CC by 2.0, COD Newsroom via Flickr

At this point, you are pretty close to selecting the right electrode as requested by your colleague, but you have a couple final choices to make. You need to know what the diameter of the electrode should be and the amperage that is right for the chosen diameter.

The wire’s diameter determines the overall size of the welding rod. The chemical coating is not measured as part of the rod’s diameter. The smaller the diameter, the less current required to create the weld. Smaller diameters also issue less filler material. Don’t worry.

Other Welding Rod Chart Functions

This information should be in the welding rod chart as well. To pick the right rod diameter, you will need to know what type of joint the welder is working on and what the thickness of the base metal is. Larger welds often use larger diameter rods, as a point of reference. Allowable amperage rankings will tell you how much heat a particular metal can take.

You will need to know this to make sure you don’t select the right diameter but the wrong amperage and risk a defect or lost time and money if a weld goes bad.

Keep Those Rods Safe and Sound

Man Learning how to weld titanium pipes who uses Welding Rod Chart as a guide

Image: CC by 2.0, PEO ACWA, via Flickr

Finally, remember that once you open the seal on a box of electrodes, you warm them in a rod oven at around 250 degrees for a half hour or more before using them. Knowing that you should not heat the rods more than three times, you do some math.

You do this to get a good sense of how much consumables you or your colleague will need in the field. These calculations may also be found in some welding rod charts.

Welding Rod Chart Reading Skills

As always, time and practice will help you gain both the knowledge and skill necessary to become a master welder. Practicing with different welding guns and electrodes on different metals ensures higher pay. You will get a sense of how each electrode reacts to the weld.

Take time to learn how to weld, the industry and your shop’s vernacular. Know that there is a standard set forth by industry experts, and your shop. Ultimately, a welding rod chart helps you make heads and tails of both your colleagues’ requests and the tools you need to get the weld done. If you remember these things, your apprenticeship should go as smoothly as possible.

Featured Image: Public Domain, Official U.S. Navy Page, Flickr

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