Steel CPM M4-ANN vs CPM M4 HT64-66
Steel · CPM M4 temper comparison
CPM M4-ANN and CPM M4 HT64-66 are two conditions of the same steel grade, CPM M4: ANN (annealed) versus HT64-66 (hardened & tempered to 64–66 HRC). The chemistry is identical, so every difference below comes from the condition. CPM M4 HT64-66 is the stronger of the two: yield strength 2,000 MPa (290 ksi) against 550 MPa (79.8 ksi) for CPM M4-ANN, about 3.6 times as much; tensile strength follows at 2,200 MPa (319 ksi) vs 850 MPa (123 ksi). In exchange, CPM M4-ANN is the more ductile: elongation 12% versus 0.5% for CPM M4 HT64-66, and CPM M4 HT64-66 is harder (740 HB vs 241 HB). CPM M4-ANN conducts electricity better (3.1 % IACS vs 2.5 % IACS). On the shop floor, CPM M4-ANN machines more easily (poor vs not recommended) and CPM M4-ANN welds better (poor vs not recommended).
CPM M4-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
CPM M4 HT64-66Choose it when strength drives the design.
CPM M4-ANN vs CPM M4 HT64-66: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 168 GPa24.4 Msi · Poisson's Ratio 0.28 · Hardness, Rockwell B 99 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.97 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,250°C2,282 °F · Liquidus Temperature 1,400°C2,552 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.2 µm/m·K6.2 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 540°C1,004 °F · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 45 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 75 MJ/kg32,244 BTU/lb · Embodied Carbon (primary production) 5.2 kg CO₂/kg · Embodied Water 110 L/kg13.2 gal/lb · Typical Recycled Content 20%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
CPM M4-ANN vs CPM M4 HT64-66 — frequently asked
Is CPM M4 HT64-66 stronger than CPM M4-ANN?
Yes. CPM M4 HT64-66 has a typical yield strength of 2,000 MPa (290 ksi) against 550 MPa (79.8 ksi) for CPM M4-ANN — about 3.6 times as much. Tensile strength is 2,200 MPa (319 ksi) vs 850 MPa (123 ksi).
Which condition does FabDigit quote by default, ANN or HT64-66?
ANN is the default CPM M4 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, CPM M4-ANN or CPM M4 HT64-66?
CPM M4-ANN. Its machinability rates poor (25/100) against not recommended (4/100) for CPM M4 HT64-66; for welding the order is CPM M4-ANN first (poor, 20/100) then CPM M4 HT64-66 (not recommended, 5/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in CPM M4-ANN and CPM M4 HT64-66 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.