Stainless Steel 1.3940 vs 1.3955
Stainless Steel · grade comparison
Stainless Steel 1.3940 and 1.3955 are both stainless steel grades. Both yield at about 250 MPa — strength does not separate them. 1.3955 runs hotter in service (760°C vs 425°C continuous). On the shop floor, 1.3940 welds better (excellent vs very good) and 1.3940 forms better (fair vs poor).
1.3940Choose it when it will be welded.
1.3955Choose it when the part sees heat.
1.3940 vs 1.3955: 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.
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Compressive Strength
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 193 GPa28 Msi · Reduction in Area 60% · Fracture Toughness (K_IC) 200 MPa·√m182 ksi·√in · Hardness, Brinell 140 HB · Hardness, Rockwell B 77 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 16.2 W/m·K9.4 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 2.3 % IACS
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.08 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Same in both: Machinability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Typical Recycled Content
Same in both: Embodied Water 130 L/kg15.6 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Same in both: Specific Stiffness (E / density) 24.9 MN·m/kg · Thermal Diffusivity 4.2 mm²/s · 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 | 1.3940 | 1.3955 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
1.3940 vs 1.3955 — frequently asked
What is the difference between 1.3940 and 1.3955?
Stainless Steel 1.3940 and 1.3955 are both stainless steel grades. Both yield at about 250 MPa — strength does not separate them. 1.3955 runs hotter in service (760°C vs 425°C continuous).
Which is cheaper, 1.3940 or 1.3955?
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 welds better, 1.3940 or 1.3955?
1.3940. Its weldability rates excellent (88/100) against very good (75/100) for 1.3955.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1.3940 and 1.3955 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.