DATA SHEET - Crucible Industries

1 020406080100120140160180200220240260 CRUCIBLECPM Rex 121 is a high vanadium cobalt-bearing toolsteel designed to offer the highest combination of wearresistance, attainable hardness, and red hardness availablein a high speed steel. Its superior red hardness permitshigher cutting speeds compared to other high speedsteels. Its superior wear resistance, owing to its highvanadium content, helps to maintain a sharp cutting edgeat increased cutting speeds. CPM Rex 121 also bridgesthe performance gap between high alloy tool steels andcarbide materials. It may be used for cutting tools, wherehigh cutting speeds demand higher heat resistance, butcarbide is too brittle, or for high wear tooling applications(punches and dies) where carbide tools are too CPM process results in a homogeneous microstructurewith a finer, more uniform carbide distribution imparting superiordimensional stability, grindability and toughness when comparedto steels produced by conventional processes.

2 The CPMprocess also allows the design of more highly alloyed gradeswhich cannot be produced by conventional Powder Compaction Tooling Broaches Milling CuttersDie Inserts Wear PartsGuide RollsNote: These are some typical applications. Your specific application shouldnot be undertaken without independent study and evaluation for ResistanceDepending on the application, the wear resistance ofCPM Rex 121 is approximately 50-100% better than CPMRex T15, CPM Rex 76 or CPM ToughnessDepending on the heat treatment, the impact toughness ofCPM Rex 121 is approximately comparable to that of CPM15V or conventionally melted T15.

3 Red HardnessThe red hardness of CPM Rex 121 is higher than that ofCPM Rex 76. CPM Rex 121 can retain a room temperaturehardness of HRC 60 even after tempering at 1200 F (650 C).Its high red hardness may be particularly useful for high cuttingspeed operations. WhenCPM Rex 121 is used in place ofconventional cobalt-bearing high speed steels in cuttingtools, cutting speeds may be increased by approximately25%-50%, depending on application CPM Rex 121 Issue # ( )*Conventional High Speed Steel CPM High Speed SteelHigh Speed Steel ComparagraphPhysical PropertiesTypical ApplicationsRelative Mechanical PropertiesM1 M2 T1 M7 M3 M4 T4 M35 M42 CPM CPM CPM T15 CPM CPMRex 20 Rex 45 Rex 54 Rex 76 Rex 121 Super High Speed Types (V+Co)

4 *Because of the extremely fine and uniform microstruc-ture provided by the CPM ( Crucible Particle Metallurgy)process, sulfur may be added if desired to improve themachinability. The higher sulfur content benefits the tool-maker by allowing ease of manufacture, and the tool userby allowing easier resharpening. The CPM processensures that the additional sulfur will not detrimentallyaffect the tool s HardnessToughness CPMWear ResistanceToughness ConventionalGeneral Purpose Vanadium Types Cobalt Types Elastic Modulus31X106psi 214 GPaSpecific of Thermal Expansion F Cin/in/ Fmm/mm/ X 10-6 X X10-6 X X X X 10-6 Crucible Industries LLC Crucible Industries , Crucible Industries logo, CPM, Rex 20, 45, 54, 76 and 121 are all trade-marks of Crucible Treat Response (HRC)- Oil or Salt Quench (Note A)

5 TemperingTemperature1875 F2050 F 2150 F2200 F F ( C) (1025 C) (1120 C) (1175 C) (1205 C) as-quenched716967651000 (540) For Maximum Toughness and Effective Stress Relieving1025 (550) (565) 70691100 (595) (650)55565859 NOTE A: RESULTS MAY VARY WITH HARDENING METHOD AND SECTION SIZE. SALTOR OIL QUENCHING WILL GIVE MAXIMUM RESPONSE. VACUUM OR ATMOSPHERECOOLING MAY RESULT IN 1 POINT HRC time atAust. temp. (mins)30201510 Minimum numberof tempers 2334 AnnealingHeat to 1650 F (900 C), hold 2 hours, slow cool no fasterthan 25 F (15 C) per hour to 1000 F (540 C), then furnacecool or cool in still air to room Hardness: Approx.

6 BHN 360/410 (HRC 38/44)Stress RelievingAnnealed parts: Heat to 1100-1300 F (595-705 C), hold2 hours, then air cool or furnace cool. Hardened parts: Heat to 25-50 F (15-30 C) below originaltempering temperature, hold 2 hours, then air cool or (Salt Bath or Vacuum Furnace preferred.)Pre-heat: 1500-1550 F (815-845 C), hold long enough tosoak through. A second pre-heat at 1850-1950 F (1010-1065 C) is recommended when hardening from over2100 F (1150 C)Austenitize:1875-2200 F (1025-1205 C) Hold time attemperature: 5-30 minutes depending on :Quench rapidly to below 1100 F (595 C),equalize then air cool to hand warm, 125 F (50 C).

7 Saltor interrupted oil quench usually gives the best heat treatresponse for high speed steels. Vacuum hardening mayresult in slightly lower hardness for larger tools. Thequench rate from the hardening temperature to below1100 F (595 C) is critical to achieve optimum cooling rate below 1000 F (540 C) may be slower tominimize distortion if :Temper 2 to 4 times at 1000 F (540 C) or at least 2 hours at temperature for each temper.(From 2 to 4 tempers are required, depending on exacthardening temperature.) Air cool to room temperaturebetween tempers.

8 Straightening: Best when done warm 500-1000 F (260-540 C). Straightening after salt quenching, before coolingto below 500 F (260 C) is preferred if possible. This gradehas limited toughness; straightening may present a riskof 410 CPM Rex 121 07/10 Crucible Industries LLC Printed in Rex 121 can be nitrided or PVD coated if a CVD treatment is used, subsequent hardening isrequired and may result in undesirable distortion. Thehigh red hardness of CPM Rex 121 makes it a particularlygood substrate for TiAlN or similar coatings designed forhigher temperature Austenitizing Temperatures: 2150-2200 F (aim 70-71 HRC) for high speed cutting F (aim 68-69 HRC) for metalforming : Properties shown throughout this data SHEET are typical values.

9 Normalvariations in chemistry, size and heat treat conditions may cause deviations fromthese values. Thermal TreatmentsSurface TreatmentsCrucible Industries LLC575 State Fair Blvd., Solvay, NY 13209