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Steel 20NiCrMo2-2 vs 42CrMo4

Steel · grade comparison

Steel 20NiCrMo2-2 and 42CrMo4 are both steel grades. 42CrMo4 is the stronger of the two: yield strength 550 MPa (79.8 ksi) against 355 MPa (51.5 ksi) for 20NiCrMo2-2, about 55% more; tensile strength follows at 850 MPa (123 ksi) vs 580 MPa (84.1 ksi). In exchange, 20NiCrMo2-2 is the more ductile: elongation 20% versus 14% for 42CrMo4, and 42CrMo4 is harder (245 HB vs 165 HB). 42CrMo4 runs hotter in service (400°C vs 350°C continuous). On the shop floor, 20NiCrMo2-2 machines more easily (good vs fair), 20NiCrMo2-2 welds better (good vs fair), and 20NiCrMo2-2 sits in a lower cost tier (budget, $) than 42CrMo4 (standard, $$).

20NiCrMo2-2Choose 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.

20NiCrMo2-2 vs 42CrMo4: properties

20NiCrMo2-242CrMo4

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
210 GPa30.5 Msi

Tensile Strength (Ultimate)

580 MPa84.1 ksi
850 MPa123 ksi

Yield Strength (0.2% offset)

355 MPa51.5 ksi
550 MPa79.8 ksi

Elongation at Break

20%
14%

Reduction in Area

50%
40%

Shear Strength

380 MPa55.1 ksi
510 MPa74 ksi

Fatigue Strength (Endurance Limit)

275 MPa39.9 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

95 MPa·√m86.5 ksi·√in
75 MPa·√m68.3 ksi·√in

Charpy V-Notch Impact (RT)

65 J47.9 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

165 HB
245 HB

Hardness, Rockwell B

85 HRB
—

Compressive Strength

—
560 MPa81.2 ksi

Hardness, Rockwell C

—
23 HRC

Hardness, Vickers

—
258 HV

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Liquidus Temperature

1,490°C2,714 °F
1,495°C2,723 °F

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

44 W/m·K25.4 BTU/hr·ft·°F
42.6 W/m·K24.6 BTU/hr·ft·°F

Specific Heat Capacity

475 J/kg·K0.11 BTU/lb·°F
473 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

11.6 µm/m·K6.4 µin/in·°F
12.3 µm/m·K6.8 µin/in·°F

Latent Heat of Fusion

270 J/g116 BTU/lb
250 J/g107 BTU/lb

Max Service Temperature (continuous)

350°C662 °F
400°C752 °F

Same in both: Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
7.8 % IACS

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)

-0.61 V
-0.6 V

Same in both: Corrosion Resistance 12 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

62 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
55%

Weldability

55 / 100
35 / 100

Formability (cold)

55 / 100
35 / 100

Brazeability / Solderability

60 / 100
50 / 100

Polishability

60 / 100
70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

31 MJ/kg13,328 BTU/lb
30 MJ/kg12,898 BTU/lb

Same in both: Embodied Carbon (primary production) 2.2 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

74 kN·m/kg
108 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

304 kJ/m³
720 kJ/m³

Thermal Diffusivity

11.8 mm²/s
11.5 mm²/s

Thermal Shock Resistance Index

11
14

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale42CrMo420NiCrMo2-2

Manufacturing and finishing

Capability20NiCrMo2-242CrMo4
CNC machining—Yes
Sheet metal—Yes
Default condition—HR
Relative cost$ Budget$$ Standard
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

20NiCrMo2-2 vs 42CrMo4 — frequently asked

Is 42CrMo4 stronger than 20NiCrMo2-2?

Yes. 42CrMo4 has a typical yield strength of 550 MPa (79.8 ksi) against 355 MPa (51.5 ksi) for 20NiCrMo2-2 — about 55% more. Tensile strength is 850 MPa (123 ksi) vs 580 MPa (84.1 ksi).

Which is cheaper, 20NiCrMo2-2 or 42CrMo4?

20NiCrMo2-2 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, 20NiCrMo2-2 or 42CrMo4?

20NiCrMo2-2. Its machinability rates good (62/100) against fair (50/100) for 42CrMo4; for welding the order is 20NiCrMo2-2 first (good, 55/100) then 42CrMo4 (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 20NiCrMo2-2 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.