The Difference Between IF, EDDS, and VDIF Steels?
NONE!!!
Steel is, by minimal definition, an
alloy of iron and up to 2 percent carbon (if it is more than 2
percent, the alloy is cast iron). Carbon is small enough to fit
into the interstices of a primarily iron matrix, making it an
"interstitial element" in steel. If the steel alloy has an
ultralow carbon level (typically less than 50 parts per
million), most of these gaps will not be occupied and, as such,
can be called interstitial-free (IF) steel. These primarily
ferric (iron), very formable IF steels are extra-deep-drawing
steel (EDDS). Achieving this low carbon level does not occur
using conventional steel processing. Instead, the molten steel
must be put under a vacuum that decarburizes it by removing
carbon monoxide, as well as other gases like hydrogen and
nitrogen. This process is called vacuum degassing, and it is
done in the production of vacuum degassed interstitial-free
steels (VD-IF).