Click to learn more about Diehl Tool Steel's Diehl Express rapid tool steel turnaround
Accu-Square Logo

Diehl Tool Steel has been selling quality tool steel for over 85 years

Diehl Tool Steel is an ISO 9001:2008 certified company


Request a tool steel quote from Diehl Tool Steel
Email Diehl Tool Steel Customer Service


Request a quote from Diehl Tool SteelEmail Diehl Tool Steel Customer Service

Print this pageEmail this to someoneShare on LinkedInShare on Google+Share on Facebook


CPM REX 45® Powder Metal

CPM REX 45® is an 8% cobalt super high speed steel which has excellent hot hardness along with good wear resistance and toughness, making it suitable for difficult machining applications. Made by the Crucible Particle Metallurgy process, CPM REX 45® has good machinability and grindability characteristics.


BroachesEnd MillsExtrusion Punches
Forming ToolsHobsMilling Cutters
Shaper CuttersTaps



TreatmentTemperature RangeCooling/QuenchingNotes
Forging2000-2100° FSlow cool.Do not forge below 1700° F.
Annealing1600° FSlow cool 30° F per hour max. to 1000° F, then air or furnace cool1600° F and hold for 2 hours.
Stress Relieving1100-1300° FAir or furnace.After machining: 1100-1300° F and hold for 2 hours, then air or furnace cool.

Hardened parts: Temper 25° F below original tempering temperature or 1000° F minimum.

Preheating1500-1550° F1500-1550° F and equalize. A second preheat at 1800-1900° F is suggested for vacuum or atmosphere hardening.
Hardening2100-2190° FSalt, oil or atmosphere quench to 1000-1100° F, equalize, then air cool to below 125° F or hand warm. Vacuum or atmosphere quench rate through 1850-1300° F range critical to achieve optimum heat treat response.Standard recommendation to achieve HRC 68/68 is to use 2175° F.
Tempering(See Chart)1000° F minimum recommended. Triple tempering is required.
Data is typical and should not be construed as actual values for any category.
Applications and technical information require engineers and tool designers to exercise independent judgement.

Print this pageEmail this to someoneShare on LinkedInShare on Google+Share on Facebook
Request Mailed Literature
Enter your name and address and we will mail you our latest brochures and information sheets.
  • This field is for validation purposes and should be left unchanged.