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Steel 35B2 vs 42CrMo4

Steel · grade comparison

Steel 35B2 and 42CrMo4 are both steel grades. 35B2 is the stronger of the two: yield strength 760 MPa (110 ksi) against 550 MPa (79.8 ksi) for 42CrMo4, about 38% more; tensile strength follows at 950 MPa (138 ksi) vs 850 MPa (123 ksi). In exchange, 42CrMo4 is the more ductile: elongation 14% versus 12% for 35B2, and 35B2 is harder (300 HB vs 245 HB). 42CrMo4 runs hotter in service (400°C vs 300°C continuous). On the shop floor, 35B2 sits in a lower cost tier (budget, $) than 42CrMo4 (standard, $$).

35B2Choose it when strength drives the design, or when cost is the deciding factor.

42CrMo4Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

35B2 vs 42CrMo4: properties

35B242CrMo4

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

950 MPa138 ksi
850 MPa123 ksi

Yield Strength (0.2% offset)

760 MPa110 ksi
550 MPa79.8 ksi

Elongation at Break

12%
14%

Reduction in Area

45%
40%

Compressive Strength

780 MPa113 ksi
560 MPa81.2 ksi

Shear Strength

580 MPa84.1 ksi
510 MPa74 ksi

Fatigue Strength (Endurance Limit)

430 MPa62.4 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
75 MPa·√m68.3 ksi·√in

Charpy V-Notch Impact (RT)

35 J25.8 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

300 HB
245 HB

Hardness, Rockwell C

31 HRC
23 HRC

Hardness, Vickers

315 HV
258 HV

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

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

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

Specific Heat Capacity

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

Latent Heat of Fusion

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

Max Service Temperature (continuous)

300°C572 °F
400°C752 °F

Min Service Temperature

-20°C-4 °F
-40°C-40 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 7.8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

10 / 100
12 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V

Manufacturability

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

Machinability

45 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
55%

Weldability

30 / 100
35 / 100

Formability (cold)

20 / 100
35 / 100

Brazeability / Solderability

55 / 100
50 / 100

Polishability

60 / 100
70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

1.9 kg CO₂/kg
2.2 kg CO₂/kg

Embodied Water

30 L/kg3.6 gal/lb
60 L/kg7.2 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

121 kN·m/kg
108 kN·m/kg

Modulus of Resilience

1,375 kJ/m³
720 kJ/m³

Thermal Diffusivity

11.9 mm²/s
11.5 mm²/s

Thermal Shock Resistance Index

16
14

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale42CrMo435B2

Manufacturing and finishing

Capability35B242CrMo4
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.

35B2 vs 42CrMo4 — frequently asked

Is 35B2 stronger than 42CrMo4?

Yes. 35B2 has a typical yield strength of 760 MPa (110 ksi) against 550 MPa (79.8 ksi) for 42CrMo4 — about 38% more. Tensile strength is 950 MPa (138 ksi) vs 850 MPa (123 ksi).

Which is cheaper, 35B2 or 42CrMo4?

35B2 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, 35B2 or 42CrMo4?

42CrMo4, by a small margin. Both rate fair for machinability — 50/100 against 45/100 for 35B2; for welding the order is 42CrMo4 first (fair, 35/100) then 35B2 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 35B2 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.