O-1 Flat Ground Stock
Chemical Composition
Carbon (C)            .85/1.00
Manganese (Mn)  1.00/1.40
Silicon (Si)              .50 max
Tungsten (W)         .40/.60
Molybdenum (Mo)
Chromium (Cr)       .40/.60
Vanadium (V)         .30 max
Cobalt (Co)
*Nickel (Ni)            .30 max
*Unless otherwise specified, nickel plus copper equal 0.75% max. for all tool steel types
O-1 is typically bought to meet chemistry requirements rather than physical requirements. For that reason, physical properties are generally not provided unless requested prior to production. Any material can be sent to a third party after production to be tested for physical properties.
Typical Uses
Typical Applications include Blanking Dies, Bushings, Forming Dies, Master Tools, Forming Rolls, Gauges and Trim Dies.

Oil Hardening Flat Ground Stock Tool Steel

Alro stocks O1 - an oil-hardening, non-deforming tool steel which can be hardened at relatively low  temperatures. Tools and dies made from O1 will have good wearing qualities since the tungsten and higher chromium content gives improved wear resistance over the straight manganese grades.