Stainless Steel 330 vs Alloy 20
Stainless Steel · grade comparison
Stainless Steel 330 and Alloy 20 are both stainless steel grades. Alloy 20 is the stronger of the two: yield strength 310 MPa (45 ksi) against 270 MPa (39.2 ksi) for 330, about 15% more; tensile strength follows at 620 MPa (89.9 ksi) vs 585 MPa (84.8 ksi). Alloy 20 is harder — 160 HB against 150 HB for 330 — which matters for wear surfaces and threads. 330 runs hotter in service (1,150°C vs 500°C continuous). On the shop floor, Alloy 20 welds better (very good vs good).
330Choose it when the part sees heat.
Alloy 20Choose it when strength drives the design, or when surface hardness matters.
330 vs Alloy 20: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all stainless steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 1,370°C2,498 °F · Liquidus Temperature 1,425°C2,597 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Polishability
Same in both: Brazeability / Solderability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 7.5 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 3
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 330 | Alloy 20 |
|---|---|---|
| Default condition | Solution Annealed | Annealed |
| Relative cost | $$$$$ Specialty | $$$$$ Specialty |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.
330 vs Alloy 20 — frequently asked
Is Alloy 20 stronger than 330?
Yes. Alloy 20 has a typical yield strength of 310 MPa (45 ksi) against 270 MPa (39.2 ksi) for 330 — about 15% more. Tensile strength is 620 MPa (89.9 ksi) vs 585 MPa (84.8 ksi).
Which is cheaper, 330 or Alloy 20?
Both sit in the same relative cost tier ($$$$$, specialty); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 330 or Alloy 20?
Alloy 20. Its machinability rates fair (38/100) against poor (32/100) for 330; for welding the order is Alloy 20 first (very good, 80/100) then 330 (good, 62/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 330 and Alloy 20 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.