CPM S35VN is a martensitic stainless steel designed to offer improved toughness over CPM S30V. It is also easier to machine and polish than CPM S30V. Its chemistry has been rebalanced so that it forms some niobium carbides along with vanadium and chromium carbides. Substituting niobium carbides for some of the vanadium carbides makes CPM S35VN about 15-20% tougher than CPM S30V without any loss of wear resistance. CPM S35VN’s improved toughness gives it better resistance to edge chipping. Because both vanadium and niobium carbides are harder and more effective than chromium carbides in providing wear resistance, the CPM stainless blade steels offer improved edge retention over conventional high chromium steels such as 440C and D2.
Shortly after the introduction of CPM-S30V, Chris Reeve (of Chris Reeve Knives) began working with Dick Barber, a metallurgist at Crucible Steel (at the time). The goal was to create an even better version of the steel that had better machinability and finish. After several years of testing and development, the result was CPM-S35VN. Chemically the same as S30V, but with the additional of Niobium (also referred to as Columbium).