First, before we start getting a bit technical, a welding rod is simply a solid or tubular cylinder made out of the metal that will be fused to the base metal (your weld piece) to create a weld. Welding electrodes replaced the more common oxyacetylene bare bronze wires that were used while welding was still in its infancy. In today's industry some of the welding electrodes and rods have gotten very advanced due to the huge focus in welding R&D and different types of welding processes which are now available. Different chemicals have been used to enhance the different characteristics of the very many variations of electrodes which are now required to meet safety, technical and worksite expectations and performance.
If you are like many of us though, or are at least a bit familiar with the welding industry, you may have heard of common SMAW (shielded metal arc welding) electrodes such as E7018 and E6010, perhaps if you've done some GTAW (gas tungsten arc welding) most commonly known as "TIG" you may have also heard of rods such as ER70S-2 and ER70S-6, both mild carbon steel rods (with different Si contents) ((we will talk about that in a bit)). A lot of my students often become so well acquainted to these rods that they know exactly the type of characteristics they have, what amperages are best used when welding with these rods and electrodes and even the positions in which they are to be used, however... do you know what the numbers and letters designations ACTUALLY mean?
Okay, time to get just a bit technical, and.. bear with me here. Let's break things down. When looking at a welding rod or electrode and reading it from left to right, manufacturers will usually, but not always, designate the letters "E" or "ER", which let the welder know the electrode or rod can be used as you guessed it, and Electrode or a Rod or both. So looking at a E7018 electrode, we now know it can be used as an Electrode. It *could* be used as a rod as well, but because it has a flux coating like SMAW electrodes do, it is typically not designated to be used without the flux. Phew, now let's move on to the first two numbers on the electrode designation. Most common rods are going to be within the 60's and 70s as that usually matches mild steel tensile requirements. When welding engineers are thinking of the materials which will be used for a specific project, they must assign a welding electrode which either matches or overmatches the tensile requirements of the base material characteristics that will be used during the welding process. The two numbers must be multiplied by 1,000 so 60*1,000 would give us a Pound Per Square Inch of 60,000lbs. The third number is to assign a position in which an electrode can be used in (if doing SMAW), so the "1" in an E7018 electrode represents that it can be used in all welding positions which are Flat, Vertical, Horizontal and Overhead. The position designator is going to be critical when choosing the right electrodes for a project as the welding position in which weld joints will be welded in mean the difference between going over budget on a project's finances (but that is a topic for another post). Lastly, the last number is reserved for the type of flux coating chemical composition which wraps the electrode as well as the welding current in which it can be used. For the inquisitive, here is a table of different number designators and it's chemical composition as well as polarities and currents assigned.
Summary, E = Electrode 70 = 70,000lbs/sqin 1 = Welding Position 8 = Type of coating/current
That pretty much wraps up our blog post over welding electrodes. If you enjoyed it please share it with your buddies, and if you want to sound really smart next time you are having an ego contest at work, bust out your newfound knowledge of types of coatings and welding currents assigned. Later!