CPM S30V is a martensitic (hardened) powder-made (sintered) wear and corrosion-resistant stainless steel developed by Dick Barber of Crucible Industries in collaboration with knifemaker Chris Reeve.
[1] Barber received feedback from a number of other knife users and knifemakers such as Sal Glesser, Ernest Emerson, Tony Marfione, Phil Wilson, William Harsey Jr., Tom Mayo, Jerry Hossom, and Paul Bos in the development of CPM S30V.
[5] [6] Coefficient of thermal expansion In 2009, Crucible Steel introduced an update to CPM-S30V to meet the needs of renowned knife maker Chris Reeve that they called CPM-S35VN.
The addition of 0.5% Niobium, and reductions in both Carbon (from 1.45% to 1.40%) and Vanadium (from 4% to 3%) produced an alloy with 25% increase in measured Charpy V-notch toughness over S30V (Crucible claims 15-20% improvement).
In light use, edge-holding and stainless properties between S35VN versus S30V are thought to be roughly the same, and performance will often be affected nearly as much by the applied heat treatment, blade design, and the edge geometry as the differences in metal chemistry.