ER70S-6 is the general-purpose solid steel MIG wire. The 70 is tensile strength in thousands of pounds per square inch; the S means solid; the 6 denotes higher silicon and manganese content.
Those two elements act as deoxidisers — they cope with the mill scale, light rust and surface contamination that real workshop steel carries. ER70S-3 has less of them: cleaner on spotless material, less forgiving on everything else. For a home or repair workshop, ER70S-6 is the correct default and is what SG2 and G3Si1 designate in European labeling.
The questions welders ask
Is SG2 the same thing?
Effectively yes. SG2 is the German designation and G3Si1 the European standard number for what the American system calls ER70S-6. Wire sold under any of the three labels is the same product, which is why listings often print all of them.
Last reviewed 2026-08-14