The Forney 42290 .024 (er-7os-6) mild steel MIG welding wire is a high strength mild steel MIG Wire. Ideal for auto body repair and fabrication on most ferrous metals. Contains a high level of manganese and silicon for a superior weld, even on rusty, dirty steel. Produces a smooth bead which requires less grinding. Not recommended for aluminum engines. Yellow color coding on label. Mig welding wire selection is based primarily on the base metal composition. In general, The finished weld metal should have mechanical properties similar to those of the base material.