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Steel SCM432 vs SNC631

Steel · grade comparison

Steel SCM432 and SNC631 are both steel grades. SCM432 is the stronger of the two: yield strength 850 MPa (123 ksi) against 750 MPa (109 ksi) for SNC631, about 13% more; tensile strength follows at 1,000 MPa (145 ksi) vs 900 MPa (131 ksi). In exchange, SNC631 is the more ductile: elongation 20% versus 17% for SCM432, and SCM432 is harder (293 HB vs 269 HB). On the shop floor, SCM432 welds better (45 vs 35 out of 100).

SCM432Choose it when strength drives the design, or when it will be welded.

SNC631Choose it when the part is bent, formed or impact-loaded.

SCM432 vs SNC631: properties

SCM432SNC631

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
205 GPa29.7 Msi

Tensile Strength (Ultimate)

1,000 MPa145 ksi
900 MPa131 ksi

Yield Strength (0.2% offset)

850 MPa123 ksi
750 MPa109 ksi

Elongation at Break

17%
20%

Reduction in Area

56%
58%

Compressive Strength

860 MPa125 ksi
760 MPa110 ksi

Shear Strength

600 MPa87 ksi
560 MPa81.2 ksi

Fatigue Strength (Endurance Limit)

470 MPa68.2 ksi
430 MPa62.4 ksi

Fracture Toughness (K_IC)

85 MPa·√m77.4 ksi·√in
95 MPa·√m86.5 ksi·√in

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
95 J70.1 ft·lbf

Hardness, Brinell

293 HB
269 HB

Hardness, Rockwell C

31 HRC
27 HRC

Hardness, Vickers

308 HV
283 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.

Melting Point (Solidus)

1,420°C2,588 °F
1,425°C2,597 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Liquidus Temperature 1,495°C2,723 °F

Thermal

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

Thermal Conductivity

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

Specific Heat Capacity

473 J/kg·K0.11 BTU/lb·°F
470 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

Latent Heat of Fusion

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

Min Service Temperature

-40°C-40 °F
-60°C-76 °F

Same in both: Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
7.2 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.4×10⁻⁷ Ω·m9.45 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.62 V
-0.61 V

Corrosion Resistance

12 / 100
13 / 100

Manufacturability

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

Weldability

45 / 100
35 / 100

Formability (cold)

40 / 100
30 / 100

Castability

—
25 / 100

Same in both: Machinability 55 / 100 · Machinability Rating (AISI 1212 = 100 %) 55% · Brazeability / Solderability 55 / 100 · Polishability 65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

28 MJ/kg12,038 BTU/lb
32 MJ/kg13,758 BTU/lb

Embodied Carbon (primary production)

2.1 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

45 L/kg5.4 gal/lb
65 L/kg7.8 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

127 kN·m/kg
115 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

1,745 kJ/m³
1,372 kJ/m³

Thermal Diffusivity

11.3 mm²/s
10.3 mm²/s

Thermal Shock Resistance Index

16
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 scaleSCM432SNC631

Manufacturing and finishing

CapabilitySCM432SNC631
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

SCM432 vs SNC631 — frequently asked

Is SCM432 stronger than SNC631?

Yes. SCM432 has a typical yield strength of 850 MPa (123 ksi) against 750 MPa (109 ksi) for SNC631 — about 13% more. Tensile strength is 1,000 MPa (145 ksi) vs 900 MPa (131 ksi).

Which is cheaper, SCM432 or SNC631?

Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which welds better, SCM432 or SNC631?

SCM432. Its weldability rates fair (45/100) against fair (35/100) for SNC631.

Ready to make it?

Upload a CAD file and FabDigit prices the part in SCM432 and SNC631 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.