Filler wires for the MIG welding process come in a range of diameters e.g. 0.6mm to 2.4mm and various sizes of reel weight/diameter.
The type of wire selected is chosen normally to match the material to be welded and provide the required strength.
Wires of dissimilar materials can be used for some cases which could include hard facing or brazing. Hard wires will utilise wire feed rolls with V style groove whereas soft alloy wires will require wire feed rolls with U style groove to reduce any deformation of the wire shape when pressure is applied.
Cored wires can be used for hard facing, high strength or high speed welding.
These wires consist of an outer metal sheath and contain either a flux or metal powder core. Due to the nature of the construction they often require specially designed knurled feed rolls.
For more details on individual wires please consult the material data sheets supplied by the manufacturer.