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Steel 18Cr2Ni4WA vs 4320

Steel · grade comparison

Steel 18Cr2Ni4WA and 4320 are both steel grades. 18Cr2Ni4WA is the stronger of the two: yield strength 1,150 MPa (167 ksi) against 415 MPa (60.2 ksi) for 4320, about 177% more; tensile strength follows at 1,350 MPa (196 ksi) vs 640 MPa (92.8 ksi). In exchange, 4320 is the more ductile: elongation 22% versus 13% for 18Cr2Ni4WA, and 18Cr2Ni4WA is harder (400 HB vs 187 HB). 4320 runs hotter in service (350°C vs 180°C continuous) and 4320 conducts heat better (44 W/m·K vs 30 W/m·K). On the shop floor, 4320 machines more easily (fair vs poor) and 4320 welds better (fair vs poor).

18Cr2Ni4WAChoose it when strength drives the design.

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

18Cr2Ni4WA vs 4320: properties

18Cr2Ni4WA4320

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

210 GPa30.5 Msi
205 GPa29.7 Msi

Shear Modulus

81 GPa11.7 Msi
80 GPa11.6 Msi

Bulk Modulus

165 GPa23.9 Msi
160 GPa23.2 Msi

Poisson's Ratio

0.3
0.29

Tensile Strength (Ultimate)

1,350 MPa196 ksi
640 MPa92.8 ksi

Yield Strength (0.2% offset)

1,150 MPa167 ksi
415 MPa60.2 ksi

Elongation at Break

13%
22%

Reduction in Area

55%
50%

Compressive Strength

1,150 MPa167 ksi
—

Shear Strength

810 MPa117 ksi
415 MPa60.2 ksi

Fatigue Strength (Endurance Limit)

600 MPa87 ksi
300 MPa43.5 ksi

Fracture Toughness (K_IC)

80 MPa·√m72.8 ksi·√in
—

Charpy V-Notch Impact (RT)

95 J70.1 ft·lbf
70 J51.6 ft·lbf

Hardness, Brinell

400 HB
187 HB

Hardness, Rockwell C

43 HRC
—

Hardness, Vickers

420 HV
—

Hardness, Rockwell B

—
90 HRB

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °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

30 W/m·K17.3 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

Max Service Temperature (continuous)

180°C356 °F
350°C662 °F

Min Service Temperature

-70°C-94 °F
-60°C-76 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

5.5 % IACS
—

Electrical Resistivity

3.1×10⁻⁷ Ω·m12.2 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)

-0.58 V
-0.6 V

Corrosion Resistance

14 / 100
11 / 100

Manufacturability

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

Machinability

20 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

20%
55%

Weldability

20 / 100
40 / 100

Formability (cold)

20 / 100
45 / 100

Brazeability / Solderability

40 / 100
55 / 100

Polishability

70 / 100
60 / 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)

2.8 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

70 L/kg8.4 gal/lb
50 L/kg6 gal/lb

Typical Recycled Content

25%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

172 kN·m/kg
82 kN·m/kg

Specific Stiffness (E / density)

26.8 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

3,149 kJ/m³
420 kJ/m³

Thermal Diffusivity

8.1 mm²/s
11.8 mm²/s

Thermal Shock Resistance Index

17
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 scale432018Cr2Ni4WA

Manufacturing and finishing

Capability18Cr2Ni4WA4320
CNC machining—Yes
Sheet metal—Yes
Default condition—HR
Relative cost$$$ Premium$$$ 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.

18Cr2Ni4WA vs 4320 — frequently asked

Is 18Cr2Ni4WA stronger than 4320?

Yes. 18Cr2Ni4WA has a typical yield strength of 1,150 MPa (167 ksi) against 415 MPa (60.2 ksi) for 4320 — about 177% more. Tensile strength is 1,350 MPa (196 ksi) vs 640 MPa (92.8 ksi).

Which is cheaper, 18Cr2Ni4WA or 4320?

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

Which is easier to machine, 18Cr2Ni4WA or 4320?

4320. Its machinability rates fair (50/100) against poor (20/100) for 18Cr2Ni4WA; for welding the order is 4320 first (fair, 40/100) then 18Cr2Ni4WA (poor, 20/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 18Cr2Ni4WA 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.