As the name itself hints, HVF or high velocity forming refers to a set of techniques which are used for metal forming. These techniques could include methods such as explosive forming, electromagnetic forming and so forth. All these techniques involve imparting a high kinetic energy to the work piece by accelerating it to a highly velocity, before it is made to hit the appropriate die or made to undergo the process of plastic the formation.
I must also tell you that although this method seems very new, it was discovered more than 100 years ago and metals were being worked upon using HVF techniques as early as the 1930s. Due to the nature of the operations it would also be appropriate to name this technique as highly velocity deformation rather than high velocity formation.
One main advantage of using HVF techniques is that very complex shaped parts can be formed in a single operation, rather than carrying out a series of operations to achieve the same results via conventional forming techniques.
A wide variety of operations which are conventionally carried out using traditional methods can be done using highly velocity techniques, and these processes include those of extrusion, die-forging, punching, joining and so forth. The list of materials which can be formed using high velocity methods contains a wide variety of materials including magnesium, aluminium, zirconium, stainless steel, alloys steel etc.