Achieving quality results in any welding operation is a matter of having the right equipment and filler metal, as well as the appropriate level of welding operator skill to complete the job efficiently and accurately. Productivity and cost savings matter in an industry where competition can be tight.

In addition to the right welding technique, it is also beneficial for welding operators to have a solid understanding of the welding procedures required for the application and know the classifications of filler metals being used. 

Why Stick Electrodes and Filler Metal Classifications Matter

American Welding Society (AWS) classifications for filler metals provide valuable information about their usability, including what materials they are best suited for and how to use these products in a way that maximizes performance. They also offer insight into the mechanical properties that a given filler metal will provide.  

AWS classifications standardize filler metals, ensuring clarity on the results a specific stick electrode or wire will produce. Filler metal manufacturers use these standards to ensure consistency in welding, chemistry, and mechanical properties across brands. If the main supplier runs out, a backup manufacturer can offer a filler metal with the same AWS classification. That filler metal may weld slightly differently but will have the same chemical and mechanical properties. For example, arc starting or wetting may vary, but overall usability and performance remain consistent.

Understanding AWS Designators: The Key to Stick Electrode Performance

AWS classifications help welding operators unfamiliar with a product understand its properties without knowing the trade name. Armed with this information, they can look at the classification and understand its properties. For example, how to operate it and whether it delivers low diffusible hydrogen. 

The most important information provided by AWS classifications are designators that indicate:

1) Whether the product is a stick electrode, solid wire or tubular wire

2) The position in which it should be used

3) Its strength classifications

4) Its chemistry/composition 

The sections below outline examples of these critical classifications, along with charts for three common AWS carbon steel filler metal specifications. These charts and explanations help demonstrate the key differences between classifications, and provide insight into other optional designators, which can be equally important to understand.

Keep in mind that AWS classifications vary in their nomenclature between stick electrodes, solid wires and flux-cored wires discussed here.  However, products within the following specification examples — AWS A5.1 (Carbon Steel Electrodes for Shielded Metal Arc Welding), A5.18 (Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding) and A5.20 (Carbon Steel Electrodes for Flux Cored Arc Welding) — are all filler metals usable for a variety of mild steel applications. These include general fabrication, rail car fabrication, shipbuilding, heavy equipment manufacturing and more. 

AWS A5.1: Carbon Steel Electrodes for Shielded Metal Arc Welding

This AWS specification provides the standards for, among other filler metals, a common classification of stick electrode: E7018. 

Like other stick electrodes, E7018 products have four key designators in their classification. See Figure 1.  

A welding electrode is defined by AWS A3.0 Standard Welding Terms and Definitions “as a component of welding circuit through which current is conducted and that terminates at the arc, molten conductive slag, or base metal.”  

E indicates an electrode, 70 shows tensile strength (ksi), 1 means all-position welding, and 8 represents the product’s coating.

Optional Designators for Stick Electrodes: What Do They Indicate?

Stick electrodes can also feature optional designators, as in the above example. 

 1 – Designates that the electrode meets the requirements for improved toughness and ductility

 H – Designates that the electrode meets the requirements of diffusible hydrogen testing

 R – Designates that the electrode meets requirements of absorbed moisture test/ optional supplement for low hydrogen electrodes

Some stick electrodes also feature an M, denoting an electrode intended to meet most military requirements. 

AWS A5.18: Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding

AWS ER70S-3 solid wire is a common filler metal within the A5.18 specification. Like the stick electrode example above, solid wires have a designator starting with E (Electrode) and an R (Rod). Welding rod in AWS A3.0 Standard Welding Terms and Definitions is defined “as a form of welding filler metal, normally packaged in straight lengths, that does not conduct the welding current.”

The product can be used as an electrode or rod, typically cut into solid lengths for the GTAW process.
The S later in the classification designates that this is a solid wire product. See Figure 2 for details on AWS solid wire classifications, including chemical composition and other key indicators.

Solid wires can also feature an optional designator of H, which, like a stick electrode indicates the electrode or rod meets requirements of diffusible hydrogen. 

AWS A5.20: Carbon Steel Electrodes for Flux-Cored Arc Welding

Lastly, as an example of an AWS classification for a gas-shielded flux-cored wire, consider an E70T-1X product in Figure 3 below. This classification illustrates the use of additional designators, such as the C/M, which indicates that the wire can be used with either 100 percent CO₂ or mixed gas of CO₂ and argon. Again, the H represents the diffusible hydrogen levels.

The optional designator of J here shows the electrode meets the requirements for improved toughness and will deposit weld metal with CVN properties of at least 20ft.lbs at -40 Fahrenheit.

There are also D or Q designators that can appear in AWS classifications for flux-cored wires. These show that the weld metal will meet supplemental mechanical property requirements with welding done using low heat input, fast cooling rate procedures and using high heat input, slow cooling rate procedures. 

Stick Electrodes vs. Solid and Flux-Cored Wires: Key Differences

Regardless of the filler metal being used for the job — stick electrode, solid wire or flux-cored wire — understanding AWS classifications can help welding operators know the performance that they will gain from a given product and the way it is best used. As with any part of the welding operation, greater knowledge can lead to greater welding performance. 

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