Flux-Cored Electrode Usability Designators: What Do They Mean?

Q: I am a new salesperson for a welding supply company. I have noticed that the AWS classification number for many of the flux-cored wires we carry are the same on the front end, but then have different dash numbers on the back end. Some example numbers are E71T-1, E71T-8, E71T-9, E71T-11, etc. Some wires even have two or three numbers on them.

I have heard that these “dash numbers” are called performance capabilities numbers. But what exactly do they mean? Also, how can some wires have more than one AWS number?

A: The dash numbers you are asking about are called “usability designators” and refer to the usability of the electrode with requirements for polarity and general operating characteristics. Before discussing the specifics of each designator, a quick review of the meaning of an electrode’s entire American Welding Society (AWS; Miami, FL) classification number is in order.

Figure 1 shows the key to an electrode’s AWS classification number. Each letter and digit in the number indicates something about the electrode. Complete details about these electrode classification numbers and more are contained in the AWS document A5.20/A5.20M:2005, titled “Specification for Carbon Steel Electrodes for Flux Cored Arc Welding”.

As stated earlier, the usability designators for flux-cored electrodes specify the requirements for polarity and general operating characteristics. These designators may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, G or GS. Each usability designation indicates a general grouping of electrodes that contain similar usability characteristics.

The exceptions are the “G” and “GS” classifications, where usability characteristics may differ between similarly classified electrodes. The “G” stands for “general” classification. “GS” stands for general, “single” pass only applications. In both cases, it is general because not all of the particular requirements specified for the other designation classifications are specified for this classification.

The intent for the general designation is to allow newly developed flux-cored electrodes that may differ in one way or another to all the other usability designations a way to still be classified according to the filler metal specification. This allows an electrode to be used right away, without having to wait potentially years for the filler metal specification to be revised to create a new usability designation.

The usability designator also indicates a particular flux-cored electrode’s type of shielding system. AWS classifies all flux-cored electrodes into one group for the flux-cored arc welding (FCAW) process.

However, there are two fundamentally different categories or sub-sets of electrodes in this group. These include self-shielded, flux-cored electrodes (FCAW-S process) and gas-shielded, flux-cored electrodes (FCAW-G process). They all are tubular electrodes with fluxing elements inside the electrode that, among other things, produce a slag covering of the weld.

Please note that self-shielded electrodes completely produce their own shielding system (like shielded metal arc welding (SMAW) or stick electrodes), while gas-shielded electrodes also utilize an external shielding gas system (i.e., they are double shielded).
These usability designators can be sub-divided into the two main categories of electrodes as follows.

• Self-Shielded, Flux-Cored Electrodes: T-3, -4, -6, -7, -8, -10, -11, -13, -14, -G, -GS
• Gas-Shielded, Flux-Cored Electrodes: T-1, -2, -5, -9, -12, -G, – GS

Detailed information on each of these usability designation classifications are found in the AWS A5:20/A5.20M:2005* carbon steel flux cored filler metal specification. Various tables in the specification include requirements for each usability designation.

Table 1 lists the required mechanical properties. Table 2 lists the “Electrode Usability Requirements”, including position of welding, use or none use of an external shielding gas, polarity and application (single or multi-pass).