2026-10-10 · 6 min read
E71T-GS and E71T-1C are both carbon steel flux-cored wires classified to AWS A5.20, and they are often quoted against each other. They solve the same problem — depositing weld metal from a continuously fed tubular electrode — but they protect the molten weld differently, and that single difference changes the polarity you set on the machine, the positions you can weld, and whether the wire belongs on a shop floor or out on site.
The difference is how the arc is shielded
A flux-cored electrode is a steel tube filled with flux. On a self-shielded wire, that flux is the only thing protecting the weld: as it burns it generates the shielding atmosphere, so no gas cylinder or hose is connected. On a gas-shielded wire, the flux works alongside an externally supplied shielding gas — for E71T-1C that is carbon dioxide, or an argon/CO2 blend.
The classification lettering records this. In E71T-1C, the trailing C denotes the CO2 shielding medium. E71T-GS and E71T-11 carry no gas designator because they need none.
That changes the polarity, not just the plumbing
Self-shielded and gas-shielded flux-cored wires run on opposite polarity. This is the detail most often set wrong on the machine, and it shows up immediately as a rough, spattery arc.
| Wire | Shielding | Polarity | Positions |
|---|---|---|---|
| E71T-GS | Self-shielded (no gas) | DC − | PA, PB, PC, PD, PE |
| E71T-11 | Self-shielded (no gas) | DC − | PA, PB, PC, PD, PE, PG |
| E71T-1C | CO2 (or Ar/CO2 blend) | DC + | PA, PB, PC, PD, PE, PF |
E71T-11 is the multi-pass member of the self-shielded family and adds vertical-down (PG) to the position list, which is why it is the usual choice for pipeline and structural work in the field. E71T-GS is the general-purpose single-pass wire in the same family.
What the two wires deposit
Typical as-deposited chemistry and mechanical properties, from our own production data:
| E71T-GS | E71T-11 | E71T-1C | |
|---|---|---|---|
| Carbon (C) | 0.09 | 0.08 | 0.05 |
| Manganese (Mn) | 0.88 | 0.60 | 1.35 |
| Silicon (Si) | 0.34 | 0.14 | 0.45 |
| Yield strength | 450 MPa | 480 MPa | 480 MPa |
| Tensile strength | 530 MPa | 530 MPa | 580 MPa |
| Elongation | — | 23% | 27% |
| Impact | — | 105 J at −20 °C | 128 J at −20 °C |
The gas-shielded wire carries the higher manganese and silicon — the deoxidisers that let the weld tolerate a less perfectly cleaned plate — and it posts the higher tensile strength and elongation. The self-shielded wires trade some of that for independence from gas supply.
Choosing between them
Reach for a gas-shielded E71T-1C when you are working indoors or in still air and want the best-looking bead, the most forgiving arc on mill scale, and the highest mechanical properties of the three. It is a natural fit for structural, pressure-vessel and heavy equipment fabrication where the work comes to the machine.
Reach for a self-shielded wire when the job moves and the gas bottle cannot follow: outdoor erection, pipeline work, bridges, repair and maintenance in the field. Wind that would blow a shielding gas cloud away simply does not affect a self-shielded wire. The trade-offs are a rougher bead appearance and more fume, so ventilation matters more.
- Shop floor, best appearance, highest strength → E71T-1C
- Field work, wind, no gas supply, all positions including vertical-down → E71T-11
- General single-pass work with a self-shielded wire → E71T-GS
- Multi-pass structural work with a self-shielded wire → E71T-11, not E71T-GS
The Chinese standard equivalents
If you are specifying to the Chinese national standard rather than to AWS, the designations to look for are GB/T 10045 E501T-GS for the self-shielded general-purpose wire, E501T-11, and E501T-1 or E501T-1/9 for the CO2-shielded wire that corresponds to E71T-1C.
Tell us the position, whether the work is indoors and whether you have gas available, and we will confirm which of the three suits the job. Diameters and spool or drum options for each are on the product pages.