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Steel 35# vs C12A

Steel · grade comparison

Steel 35# and C12A are both steel grades. C12A is the stronger of the two: yield strength 470 MPa (68.2 ksi) against 330 MPa (47.9 ksi) for 35#, about 42% more; tensile strength follows at 650 MPa (94.3 ksi) vs 560 MPa (81.2 ksi). C12A is harder — 215 HB against 160 HB for 35# — which matters for wear surfaces and threads. C12A is stiffer (218 GPa vs 207 GPa) and C12A runs hotter in service (600°C vs 400°C continuous). On the shop floor, 35# machines more easily (good vs fair), 35# welds better (good vs fair), and 35# forms better (fair vs not recommended).

35#Choose it when the part is machined in volume, or when it will be welded.

C12AChoose it when strength drives the design, or when surface hardness matters.

35# vs C12A: properties

35#C12A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
218 GPa31.6 Msi

Shear Modulus

80 GPa11.6 Msi
84 GPa12.2 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

560 MPa81.2 ksi
650 MPa94.3 ksi

Yield Strength (0.2% offset)

330 MPa47.9 ksi
470 MPa68.2 ksi

Elongation at Break

22%
21%

Reduction in Area

50%
58%

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
295 MPa42.8 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
130 MPa·√m118 ksi·√in

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
55 J40.6 ft·lbf

Hardness, Brinell

160 HB
215 HB

Hardness, Rockwell B

83 HRB
—

Hardness, Vickers

168 HV
225 HV

Compressive Strength

—
470 MPa68.2 ksi

Hardness, Rockwell C

—
19 HRC

Same in both: Bulk Modulus 160 GPa23.2 Msi · Shear Strength 400 MPa58 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,425°C2,597 °F
1,420°C2,588 °F

Liquidus Temperature

1,500°C2,732 °F
1,490°C2,714 °F

Thermal

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

Thermal Conductivity

49 W/m·K28.3 BTU/hr·ft·°F
26 W/m·K15 BTU/hr·ft·°F

Specific Heat Capacity

477 J/kg·K0.11 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

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

Max Service Temperature (continuous)

400°C752 °F
600°C1,112 °F

Min Service Temperature

-20°C-4 °F
-30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10 % IACS
2.9 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
6×10⁻⁷ Ω·m23.6 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.65 V
-0.52 V

Corrosion Resistance

11 / 100
33 / 100

Manufacturability

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

Machinability

60 / 100
42 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
45%

Weldability

55 / 100
38 / 100

Formability (cold)

45 / 100
10 / 100

Castability

35 / 100
55 / 100

Brazeability / Solderability

65 / 100
25 / 100

Polishability

55 / 100
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
33 MJ/kg14,187 BTU/lb

Embodied Carbon (primary production)

1.9 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
45 L/kg5.4 gal/lb

Typical Recycled Content

25%
80%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

71 kN·m/kg
84 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
28.1 MN·m/kg

Modulus of Resilience

263 kJ/m³
507 kJ/m³

Thermal Diffusivity

13.1 mm²/s
7.3 mm²/s

Thermal Shock Resistance Index

11
7

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 scale35#C12A

Manufacturing and finishing

Capability35#C12A
CNC machiningYes—
Sheet metalYes—
Default conditionHR—
Relative cost$ Budget$$$ Premium
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.

35# vs C12A — frequently asked

Is C12A stronger than 35#?

Yes. C12A has a typical yield strength of 470 MPa (68.2 ksi) against 330 MPa (47.9 ksi) for 35# — about 42% more. Tensile strength is 650 MPa (94.3 ksi) vs 560 MPa (81.2 ksi).

Which is cheaper, 35# or C12A?

35# is the lower-cost material: it sits in the budget tier ($) while C12A is premium ($$$). 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, 35# or C12A?

35#. Its machinability rates good (60/100) against fair (42/100) for C12A; for welding the order is 35# first (good, 55/100) then C12A (fair, 38/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 35# and C12A 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.