Steel 420 Mod Mold Prehard vs 420 Mod Mold Q&T
Steel · 420 Mod Mold temper comparison
420 Mod Mold Prehard and 420 Mod Mold Q&T are two conditions of the same steel grade, 420 Mod Mold: Prehard (pre-hardened) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 420 Mod Mold Q&T is the stronger of the two: yield strength 1,450 MPa (210 ksi) against 860 MPa (125 ksi) for 420 Mod Mold Prehard, about 69% more; tensile strength follows at 1,750 MPa (254 ksi) vs 1,030 MPa (149 ksi). In exchange, 420 Mod Mold Prehard is the more ductile: elongation 13% versus 7% for 420 Mod Mold Q&T, and 420 Mod Mold Prehard is harder (300 HB vs 220 HB). 420 Mod Mold Prehard runs hotter in service (450°C vs 250°C continuous). On the shop floor, 420 Mod Mold Prehard machines more easily (fair vs poor) and 420 Mod Mold Prehard welds better (25 vs 15 out of 100).
420 Mod Mold PrehardChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
420 Mod Mold Q&TChoose it when strength drives the design.
420 Mod Mold Prehard vs 420 Mod Mold Q&T: 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 Prehard420 Mod Mold Q&T
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
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 · 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 %)
Weldability
Polishability
Same in both: 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 Prehard vs 420 Mod Mold Q&T — frequently asked
Is 420 Mod Mold Q&T stronger than 420 Mod Mold Prehard?
Yes. 420 Mod Mold Q&T has a typical yield strength of 1,450 MPa (210 ksi) against 860 MPa (125 ksi) for 420 Mod Mold Prehard — about 69% more. Tensile strength is 1,750 MPa (254 ksi) vs 1,030 MPa (149 ksi).
Which condition does FabDigit quote by default, Prehard or Q&T?
Annealed is the default 420 Mod Mold condition in the FabDigit quote flow (neither Prehard nor Q&T). 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 Prehard or 420 Mod Mold Q&T?
420 Mod Mold Prehard. Its machinability rates fair (35/100) against poor (20/100) for 420 Mod Mold Q&T; for welding the order is 420 Mod Mold Prehard first (poor, 25/100) then 420 Mod Mold Q&T (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420 Mod Mold Prehard and 420 Mod Mold Q&T 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.