"Folding" is a term applied to an old method of refining the quality of steel to get a more homogeneous billet. It was used to make a strong and flexible steel at a time when the raw material was usually of poor quality.
With modern steel there is no need to fold it.
The other procedure that "folding" is used for is in making damascus (pattern welded) steel. This is where layers of different types of steel are stacked, forge welded together, and then folded many times to make hundreds of layers.
I hate to sound like a broken record (for those who remember records) ,but it would be nice if you filled out your profile.
Stacy