*Always consult your Heat Treater*
      *Information Provided is General*


O-1 is an oil hardening, non-shrinking die steel which can be hardened at relatively low temperatures. Tools and dies made from O-1 will have good wearing qualities since the tungsten and higher chromium content gives improved wear resistance over the straight manganese types. Where greater stability in heat treatment and greater wear resistance is desired, an air hardening steel such as A-2 or a high carbon-high chromium steel such as D-2 should be considered.

O-1 should be heated slowly to 1475-1500° F, held at this temperature until thoroughly and uniformly heated, then quenched in oil. For large or intricately shaped sections, it is recommended to preheat at 1200-1250° F, then raising the temperature to 1475-1500° F. Do not allow pieces to remain in the quenching oil until they have cooled to room temperature but when they have cooled to approximately 150° F, transfer to the tempering furnace. Best results are obtained by hardening in atmosphere controlled furnaces, in neutral salt baths or in vacuum furnaces with an integral oil quench.

O-1 should be tempered immediately after quenching. Allow the steel to cool at least to 125-150° F on the quench, then place in temper. Cracks may result if the strains set up during quenching are not relieved immediately by tempering. Most punches and dies are tempered at 350-400° F although other tempering temperatures may be used for certain applications.

Hardening happens between 1475-1550° F.

O-1 is an oversized material.


 + .015 up to .040 on thickness

 + .080 up to .125 on width


 Up to 1″ + .007 up to .018

 1″ up to 6″ + .015 up to .040

 6″ and up + .0625 up to .250

 Hardening Temp.:    1475 through 1550°F

 Quench Medium:    Oil

 Tempering Range:    300 through 500°F

 Typical Hardness Level:    57 to 62 R/C

 Preheat Forging Temp.:    1400 through 1500°F

 Forging Temp:    1900 through 2000°F

 Anneal Temp.:    1425 through 1450°F

 Anneal Cooling Method:    Furnace cool to 1000°F or less at 100°F per  hr., then air cool

 Anneal Hardness:    212 BHN

 O-1 Material In Stock

 Color Code:   Gold 

 Flat Dimensions

  • 1/2″ x 5/8″ up to 6″ x 6″

  • Non-standard sizes, quoted upon request

 Round Dimensions

  • 3/8″ up to 17″

  • Non-standard sizes quoted upon request.

 O-1 Typical Analysis











 · Slight variations from typical analysis shown may occur in order to  maintain the desired graphitizing potential.