FabDigit

Steel SNC631 vs SCM420 vs SCr445 vs SCM422

Benchmark · 4 materials

Side-by-side benchmark of 4 steel grades.

SNC631 vs SCM420 and 2 more: properties

SNC631SCM420SCr445SCM422

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
207 GPa30 Msi
207 GPa30 Msi
206 GPa29.9 Msi

Tensile Strength (Ultimate)

900 MPa131 ksi
660 MPa95.7 ksi
1,030 MPa149 ksi
580 MPa84.1 ksi

Yield Strength (0.2% offset)

750 MPa109 ksi
440 MPa63.8 ksi
860 MPa125 ksi
370 MPa53.7 ksi

Elongation at Break

20%
22%
14%
25%

Reduction in Area

58%
52%
45%
55%

Compressive Strength

760 MPa110 ksi
880 MPa128 ksi

Shear Strength

560 MPa81.2 ksi
430 MPa62.4 ksi
620 MPa89.9 ksi
360 MPa52.2 ksi

Fatigue Strength (Endurance Limit)

430 MPa62.4 ksi
300 MPa43.5 ksi
480 MPa69.6 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

95 MPa·√m86.5 ksi·√in
65 MPa·√m59.2 ksi·√in
60 MPa·√m54.6 ksi·√in

Charpy V-Notch Impact (RT)

95 J70.1 ft·lbf
40 J29.5 ft·lbf
45 J33.2 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

269 HB
190 HB
302 HB
170 HB

Hardness, Rockwell C

27 HRC
32 HRC

Hardness, Vickers

283 HV
318 HV

Hardness, Rockwell B

91 HRB
87 HRB

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.

Density

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

Liquidus Temperature

1,495°C2,723 °F
1,500°C2,732 °F
1,490°C2,714 °F
1,500°C2,732 °F

Same in both: Melting Point (Solidus) 1,425°C2,597 °F

Thermal

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

Thermal Conductivity

38 W/m·K22 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

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

Max Service Temperature (continuous)

400°C752 °F
400°C752 °F
350°C662 °F
350°C662 °F

Min Service Temperature

-60°C-76 °F
-40°C-40 °F
-25°C-13 °F
-40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.2 % IACS
7.8 % IACS
8 % IACS
8 % IACS

Electrical Resistivity

2.4×10⁻⁷ Ω·m9.45 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in
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
-0.62 V
-0.6 V
-0.6 V

Corrosion Resistance

13 / 100
12 / 100
12 / 100
10 / 100

Manufacturability

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

Machinability

55 / 100
60 / 100
42 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
62%
45%
60%

Weldability

35 / 100
55 / 100
25 / 100
40 / 100

Formability (cold)

30 / 100
60 / 100
20 / 100
55 / 100

Castability

25 / 100

Brazeability / Solderability

55 / 100
65 / 100
45 / 100
55 / 100

Polishability

65 / 100
60 / 100
60 / 100
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

32 MJ/kg13,758 BTU/lb
30 MJ/kg12,898 BTU/lb
30 MJ/kg12,898 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

2.4 kg CO₂/kg
2.3 kg CO₂/kg
2.1 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

65 L/kg7.8 gal/lb
55 L/kg6.6 gal/lb
60 L/kg7.2 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

30%
30%
30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

115 kN·m/kg
84 kN·m/kg
132 kN·m/kg
74 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.4 MN·m/kg
26.4 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

1,372 kJ/m³
468 kJ/m³
1,786 kJ/m³
332 kJ/m³

Thermal Diffusivity

10.3 mm²/s
11.4 mm²/s
11.3 mm²/s
11.4 mm²/s

Thermal Shock Resistance Index

14
11
17
10

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 scaleSCM420SCr445SCM422SNC631

Manufacturing and finishing

CapabilitySNC631SCM420SCr445SCM422
CNC machiningYes
Sheet metalYes
Default conditionHR
Relative cost$ Budget$$ Standard$ Budget$ Budget
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.

Ready to make it?

Upload a CAD file and FabDigit prices the part in SNC631 and SCM420 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.