Steel 420 Mod Mold vs 718H
Steel · grade comparison
Steel 420 Mod Mold and 718H are both steel grades, both mold steel. 718H is the stronger of the two: yield strength 900 MPa (131 ksi) against 470 MPa (68.2 ksi) for 420 Mod Mold, about 91% more; tensile strength follows at 1,080 MPa (157 ksi) vs 760 MPa (110 ksi). In exchange, 420 Mod Mold is the more ductile: elongation 19% versus 13% for 718H, and 718H is harder (300 HB vs 220 HB). 718H runs hotter in service (450°C vs 400°C continuous) and 718H conducts heat better (33 W/m·K vs 24 W/m·K). On the shop floor, 718H welds better (fair vs poor).
420 Mod MoldChoose it when the part is bent, formed or impact-loaded.
718HChoose it when strength drives the design, or when the part sees heat.
420 Mod Mold vs 718H: 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
Shear Modulus
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, Rockwell B
Hardness, Vickers
Fracture Toughness (K_IC)
Hardness, Rockwell C
Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Same in both: Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Brazeability / Solderability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 420 Mod Mold | 718H |
|---|---|---|
| Default condition | Annealed | Prehard |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
420 Mod Mold vs 718H — frequently asked
Is 718H stronger than 420 Mod Mold?
Yes. 718H has a typical yield strength of 900 MPa (131 ksi) against 470 MPa (68.2 ksi) for 420 Mod Mold — about 91% more. Tensile strength is 1,080 MPa (157 ksi) vs 760 MPa (110 ksi).
Which is cheaper, 420 Mod Mold or 718H?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, 420 Mod Mold or 718H?
718H. Its weldability rates fair (40/100) against poor (25/100) for 420 Mod Mold.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420 Mod Mold and 718H 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.