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Steel 12Cr2Ni4A vs 4320

Steel · grade comparison

Steel 12Cr2Ni4A and 4320 are both steel grades. 12Cr2Ni4A is the stronger of the two: yield strength 950 MPa (138 ksi) against 415 MPa (60.2 ksi) for 4320, about 129% more; tensile strength follows at 1,180 MPa (171 ksi) vs 640 MPa (92.8 ksi). In exchange, 4320 is the more ductile: elongation 22% versus 12% for 12Cr2Ni4A, and 12Cr2Ni4A is harder (370 HB vs 187 HB). 4320 runs hotter in service (350°C vs 200°C continuous) and 4320 conducts heat better (44 W/m·K vs 33 W/m·K). On the shop floor, 4320 machines more easily (fair vs poor), 4320 welds better (fair vs poor), and 12Cr2Ni4A sits in a lower cost tier (standard, $$) than 4320 (premium, $$$).

12Cr2Ni4AChoose it when strength drives the design, or when cost is the deciding factor.

4320Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

12Cr2Ni4A vs 4320: properties

12Cr2Ni4A4320

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
205 GPa29.7 Msi

Tensile Strength (Ultimate)

1,180 MPa171 ksi
640 MPa92.8 ksi

Yield Strength (0.2% offset)

950 MPa138 ksi
415 MPa60.2 ksi

Elongation at Break

12%
22%

Reduction in Area

55%
50%

Compressive Strength

980 MPa142 ksi
—

Shear Strength

710 MPa103 ksi
415 MPa60.2 ksi

Fatigue Strength (Endurance Limit)

550 MPa79.8 ksi
300 MPa43.5 ksi

Fracture Toughness (K_IC)

100 MPa·√m91 ksi·√in
—

Charpy V-Notch Impact (RT)

90 J66.4 ft·lbf
70 J51.6 ft·lbf

Hardness, Brinell

370 HB
187 HB

Hardness, Rockwell C

39 HRC
—

Hardness, Vickers

390 HV
—

Hardness, Rockwell B

—
90 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.

Melting Point (Solidus)

1,430°C2,606 °F
1,425°C2,597 °F

Liquidus Temperature

1,490°C2,714 °F
1,500°C2,732 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

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

Thermal Conductivity

33 W/m·K19.1 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.5 µm/m·K6.4 µin/in·°F
11.7 µm/m·K6.5 µin/in·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

200°C392 °F
350°C662 °F

Min Service Temperature

-70°C-94 °F
-60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

5.7 % IACS
—

Electrical Resistivity

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

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

13 / 100
11 / 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

32 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

35%
55%

Weldability

30 / 100
40 / 100

Formability (cold)

30 / 100
45 / 100

Polishability

75 / 100
60 / 100

Same in both: Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

36 MJ/kg15,477 BTU/lb
31 MJ/kg13,328 BTU/lb

Embodied Carbon (primary production)

2.6 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

60 L/kg7.2 gal/lb
50 L/kg6 gal/lb

Typical Recycled Content

25%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

150 kN·m/kg
82 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

2,149 kJ/m³
420 kJ/m³

Thermal Diffusivity

8.9 mm²/s
11.8 mm²/s

Thermal Shock Resistance Index

16
12

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 scale432012Cr2Ni4A

Manufacturing and finishing

Capability12Cr2Ni4A4320
CNC machining—Yes
Sheet metal—Yes
Default condition—HR
Relative cost$$ Standard$$$ Premium
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.

12Cr2Ni4A vs 4320 — frequently asked

Is 12Cr2Ni4A stronger than 4320?

Yes. 12Cr2Ni4A has a typical yield strength of 950 MPa (138 ksi) against 415 MPa (60.2 ksi) for 4320 — about 129% more. Tensile strength is 1,180 MPa (171 ksi) vs 640 MPa (92.8 ksi).

Which is cheaper, 12Cr2Ni4A or 4320?

12Cr2Ni4A is the lower-cost material: it sits in the standard tier ($$) while 4320 is premium ($$$). 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, 12Cr2Ni4A or 4320?

4320. Its machinability rates fair (50/100) against poor (32/100) for 12Cr2Ni4A; for welding the order is 4320 first (fair, 40/100) then 12Cr2Ni4A (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 12Cr2Ni4A and 4320 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.