Steel 42CrMo4 vs C45E
Steel · grade comparison
Steel 42CrMo4 and C45E are both steel grades. 42CrMo4 is the stronger of the two: yield strength 550 MPa (79.8 ksi) against 380 MPa (55.1 ksi) for C45E, about 45% more; tensile strength follows at 850 MPa (123 ksi) vs 660 MPa (95.7 ksi). In exchange, C45E is the more ductile: elongation 18% versus 14% for 42CrMo4, and 42CrMo4 is harder (245 HB vs 190 HB). 42CrMo4 runs hotter in service (400°C vs 350°C continuous) and C45E conducts heat better (48 W/m·K vs 42.6 W/m·K). On the shop floor, C45E welds better (45 vs 35 out of 100) and C45E sits in a lower cost tier (budget, $) than 42CrMo4 (standard, $$).
42CrMo4Choose it when strength drives the design, or when the part sees heat.
C45EChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
42CrMo4 vs C45E: 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 40%
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb
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)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 26.8 MN·m/kg
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 | 42CrMo4 | C45E |
|---|---|---|
| Default condition | HR | Normalized |
| Relative cost | $$ Standard | $ Budget |
| 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 and Sheet metal. 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.
42CrMo4 vs C45E — frequently asked
Is 42CrMo4 stronger than C45E?
Yes. 42CrMo4 has a typical yield strength of 550 MPa (79.8 ksi) against 380 MPa (55.1 ksi) for C45E — about 45% more. Tensile strength is 850 MPa (123 ksi) vs 660 MPa (95.7 ksi).
Which is cheaper, 42CrMo4 or C45E?
C45E is the lower-cost material: it sits in the budget tier ($) while 42CrMo4 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, 42CrMo4 or C45E?
C45E. Its machinability rates good (55/100) against fair (50/100) for 42CrMo4; for welding the order is C45E first (fair, 45/100) then 42CrMo4 (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 42CrMo4 and C45E 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.