Cru-Wear is a steel made by Crucible and consists of:
Some information from the Spyderco website:
Cru-Wear is a high-performance "V" tool steel that is difficult to process making it challenging for knife manufacturer to work with. It follows the same high-alloy, metallurgical tool-steel recipe used to produce D2, but with greater levels of vanadium, tungsten and molybdenum. It is air-hardened and worked in a cold state. Cru-Wear exhibits exceptional toughness, impact resistance and hardness for exceptional edge retention.