Steel M3-1 Annealed vs M3-1 HT 64-66 HRC
Steel · M3-1 temper comparison
M3-1 Annealed and M3-1 HT 64-66 HRC are two conditions of the same steel grade, M3-1: Annealed versus HT 64-66 HRC (hardened & tempered to 64–66 HRC). The chemistry is identical, so every difference below comes from the condition. M3-1 HT 64-66 HRC is the stronger of the two: yield strength 2,100 MPa (305 ksi) against 550 MPa (79.8 ksi) for M3-1 Annealed, about 3.8 times as much; tensile strength follows at 2,400 MPa (348 ksi) vs 870 MPa (126 ksi). In exchange, M3-1 Annealed is the more ductile: elongation 20% versus 0.5% for M3-1 HT 64-66 HRC, and M3-1 HT 64-66 HRC is harder (860 HV vs 245 HV). M3-1 HT 64-66 HRC runs hotter in service (550°C vs 400°C continuous). On the shop floor, M3-1 Annealed machines more easily (poor vs not recommended).
M3-1 AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
M3-1 HT 64-66 HRCChoose it when strength drives the design, or when the part sees heat.
M3-1 Annealed vs M3-1 HT 64-66 HRC: 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.
M3-1 AnnealedM3-1 HT 64-66 HRC
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Vickers
Same in both: Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29 · Reduction in Area 30% · Hardness, Brinell 235 HB · Hardness, Rockwell B 99 HRB
Physical
Density and transition temperatures.
Same in both: Density 8.05 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,250°C2,282 °F · Liquidus Temperature 1,425°C2,597 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 420 J/kg·K0.1 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.3 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.55 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Same in both: Machinability Rating (AISI 1212 = 100 %) 40% · Formability (cold) 15 / 100 · Castability 25 / 100 · Brazeability / Solderability 55 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 48 MJ/kg20,636 BTU/lb · Embodied Carbon (primary production) 3.2 kg CO₂/kg · Embodied Water 110 L/kg13.2 gal/lb · Typical Recycled Content 35%
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.
M3-1 Annealed vs M3-1 HT 64-66 HRC — frequently asked
Is M3-1 HT 64-66 HRC stronger than M3-1 Annealed?
Yes. M3-1 HT 64-66 HRC has a typical yield strength of 2,100 MPa (305 ksi) against 550 MPa (79.8 ksi) for M3-1 Annealed — about 3.8 times as much. Tensile strength is 2,400 MPa (348 ksi) vs 870 MPa (126 ksi).
Which condition does FabDigit quote by default, Annealed or HT 64-66 HRC?
Annealed is the default M3-1 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, M3-1 Annealed or M3-1 HT 64-66 HRC?
M3-1 Annealed. Its machinability rates poor (30/100) against not recommended (4/100) for M3-1 HT 64-66 HRC; for welding the order is M3-1 Annealed first (poor, 15/100) then M3-1 HT 64-66 HRC (not recommended, 8/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in M3-1 Annealed and M3-1 HT 64-66 HRC 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.