The copper CuSi3 C9 soldering brazing MIG wire.
 
The CuSi3 wire is an uncoated copper wire. It is used for merging galvanized steel sheets as well as for welding low and non-alloy steel, and cast iron. Designed primarily for tinplate and other braze welding customers instead of traditional welding, where zinc removal prior to welding and re-coating is too expensive and time-consuming. It is also used for welding zinc-copper alloys and low alloy copper alloys. The silicon and manganese-containing binder exhibits good wetting properties and abrasion resistance. When welding as a shielding gas, pure Ar is usually used.
 
EN ISO 18273: S Al 5356 (AlMg5Cr(A))
AWS A5.10: ER 5356