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.