Steel 20MnCrS5 vs 42CrMo4
Steel · grade comparison
Steel 20MnCrS5 and 42CrMo4 are both steel grades. 42CrMo4 is the stronger of the two: yield strength 550 MPa (79.8 ksi) against 450 MPa (65.3 ksi) for 20MnCrS5, about 22% more; tensile strength follows at 850 MPa (123 ksi) vs 700 MPa (102 ksi). In exchange, 20MnCrS5 is the more ductile: elongation 18% versus 14% for 42CrMo4, and 42CrMo4 is harder (245 HB vs 200 HB). 42CrMo4 runs hotter in service (400°C vs 250°C continuous). On the shop floor, 20MnCrS5 machines more easily (good vs fair).
20MnCrS5Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
42CrMo4Choose it when strength drives the design, or when the part sees heat.
20MnCrS5 vs 42CrMo4: 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.
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi
Physical
Density and transition temperatures.
Liquidus Temperature
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °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)
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Same in both: Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Brazeability / Solderability
Polishability
Same in both: Weldability 35 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Water 60 L/kg7.2 gal/lb · 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 | 20MnCrS5 | 42CrMo4 |
|---|---|---|
| Sheet metal | — | Yes |
| Default condition | HR | HR |
| 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.
20MnCrS5 vs 42CrMo4 — frequently asked
Is 42CrMo4 stronger than 20MnCrS5?
Yes. 42CrMo4 has a typical yield strength of 550 MPa (79.8 ksi) against 450 MPa (65.3 ksi) for 20MnCrS5 — about 22% more. Tensile strength is 850 MPa (123 ksi) vs 700 MPa (102 ksi).
Which is cheaper, 20MnCrS5 or 42CrMo4?
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 is easier to machine, 20MnCrS5 or 42CrMo4?
20MnCrS5. Its machinability rates good (60/100) against fair (50/100) for 42CrMo4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20MnCrS5 and 42CrMo4 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.