Steel 420 Mod Mold Annealed vs 420 Mod Mold Prehard
Steel · 420 Mod Mold temper comparison
420 Mod Mold Annealed and 420 Mod Mold Prehard are two conditions of the same steel grade, 420 Mod Mold: Annealed versus Prehard (pre-hardened). The chemistry is identical, so every difference below comes from the condition. 420 Mod Mold Prehard is the stronger of the two: yield strength 860 MPa (125 ksi) against 470 MPa (68.2 ksi) for 420 Mod Mold Annealed, about 83% more; tensile strength follows at 1,030 MPa (149 ksi) vs 760 MPa (110 ksi). In exchange, 420 Mod Mold Annealed is the more ductile: elongation 19% versus 13% for 420 Mod Mold Prehard, and 420 Mod Mold Prehard is harder (300 HB vs 220 HB). 420 Mod Mold Prehard runs hotter in service (450°C vs 400°C continuous). On the shop floor, 420 Mod Mold Annealed machines more easily (45 vs 35 out of 100).
420 Mod Mold AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
420 Mod Mold PrehardChoose it when strength drives the design, or when the part sees heat.
420 Mod Mold Annealed vs 420 Mod Mold Prehard: 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.
420 Mod Mold Annealed420 Mod Mold Prehard
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 500 MPa72.5 ksi · Hardness, Rockwell B 97 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 24 W/m·K13.9 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 260 J/g112 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 3.1 % IACS · Electrical Resistivity 5.5×10⁻⁷ Ω·m21.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.35 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Polishability
Same in both: Weldability 25 / 100 · Formability (cold) 35 / 100 · Brazeability / Solderability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 52 MJ/kg22,356 BTU/lb · Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 95 L/kg11.4 gal/lb · Typical Recycled Content 60%
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.
420 Mod Mold Annealed vs 420 Mod Mold Prehard — frequently asked
Is 420 Mod Mold Prehard stronger than 420 Mod Mold Annealed?
Yes. 420 Mod Mold Prehard has a typical yield strength of 860 MPa (125 ksi) against 470 MPa (68.2 ksi) for 420 Mod Mold Annealed — about 83% more. Tensile strength is 1,030 MPa (149 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, Annealed or Prehard?
Annealed is the default 420 Mod Mold 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, 420 Mod Mold Annealed or 420 Mod Mold Prehard?
420 Mod Mold Annealed, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for 420 Mod Mold Prehard.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420 Mod Mold Annealed and 420 Mod Mold Prehard 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.