FabDigitFabDigit

Steel 42CrMo4 vs TDSiCr

Steel · grade comparison

Steel 42CrMo4 and TDSiCr are both steel grades. TDSiCr is the stronger of the two: yield strength 1,830 MPa (265 ksi) against 550 MPa (79.8 ksi) for 42CrMo4, about 3.3 times as much; tensile strength follows at 2,060 MPa (299 ksi) vs 850 MPa (123 ksi). In exchange, 42CrMo4 is the more ductile: elongation 14% versus 6% for TDSiCr, and TDSiCr is harder (595 HB vs 245 HB). 42CrMo4 runs hotter in service (400°C vs 200°C continuous) and 42CrMo4 conducts electricity better (7.8 % IACS vs 5.7 % IACS). On the shop floor, 42CrMo4 machines more easily (fair vs not recommended) and 42CrMo4 welds better (fair vs not recommended).

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

TDSiCrChoose it when strength drives the design.

42CrMo4 vs TDSiCr: properties

42CrMo4TDSiCr

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
206 GPa29.9 Msi

Shear Modulus

80 GPa11.6 Msi
79.5 GPa11.5 Msi

Tensile Strength (Ultimate)

850 MPa123 ksi
2,060 MPa299 ksi

Yield Strength (0.2% offset)

550 MPa79.8 ksi
1,830 MPa265 ksi

Elongation at Break

14%
6%

Reduction in Area

40%
50%

Compressive Strength

560 MPa81.2 ksi
2,100 MPa305 ksi

Shear Strength

510 MPa74 ksi
1,240 MPa180 ksi

Fatigue Strength (Endurance Limit)

400 MPa58 ksi
780 MPa113 ksi

Fracture Toughness (K_IC)

75 MPa·√m68.3 ksi·√in
40 MPa·√m36.4 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
—

Hardness, Brinell

245 HB
595 HB

Hardness, Rockwell C

23 HRC
55 HRC

Hardness, Vickers

258 HV
620 HV

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

Physical

Density and transition temperatures.

Density

7.85 g/cm³0.28 lb/in³
7.81 g/cm³0.28 lb/in³

Liquidus Temperature

1,495°C2,723 °F
1,490°C2,714 °F

Same in both: Melting Point (Solidus) 1,420°C2,588 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

42.6 W/m·K24.6 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

12.3 µm/m·K6.8 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
200°C392 °F

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

7.8 % IACS
5.7 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
3×10⁻⁷ Ω·m11.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 100

Manufacturability

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

Machinability

50 / 100
10 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
20%

Weldability

35 / 100
10 / 100

Brazeability / Solderability

50 / 100
20 / 100

Polishability

70 / 100
55 / 100

Castability

—
0 / 100

Same in both: Formability (cold) 35 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
2.4 kg CO₂/kg

Typical Recycled Content

30%
25%

Same in both: Embodied Water 60 L/kg7.2 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

108 kN·m/kg
264 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
26.4 MN·m/kg

Modulus of Resilience

720 kJ/m³
8,128 kJ/m³

Thermal Diffusivity

11.5 mm²/s
11.3 mm²/s

Thermal Shock Resistance Index

14
35

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 scale42CrMo4TDSiCr

Manufacturing and finishing

Capability42CrMo4TDSiCr
CNC machiningYes—
Sheet metalYes—
Default conditionHR—
Relative cost$$ Standard$$ Standard
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

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

42CrMo4 vs TDSiCr — frequently asked

Is TDSiCr stronger than 42CrMo4?

Yes. TDSiCr has a typical yield strength of 1,830 MPa (265 ksi) against 550 MPa (79.8 ksi) for 42CrMo4 — about 3.3 times as much. Tensile strength is 2,060 MPa (299 ksi) vs 850 MPa (123 ksi).

Which is cheaper, 42CrMo4 or TDSiCr?

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, 42CrMo4 or TDSiCr?

42CrMo4. Its machinability rates fair (50/100) against not recommended (10/100) for TDSiCr; for welding the order is 42CrMo4 first (fair, 35/100) then TDSiCr (not recommended, 10/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 42CrMo4 and TDSiCr 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.