Nickel Alloy Nimonic 115-ST vs Nimonic 115 ST+A
Nickel Alloy · Nimonic 115 temper comparison
Nimonic 115-ST and Nimonic 115 ST+A are two conditions of the same nickel alloy grade, Nimonic 115: ST (solution annealed) versus ST+A (solution treated 1190 °C/1.5 h AC + aged 1100 °C/6 h AC). The chemistry is identical, so every difference below comes from the condition. Nimonic 115 ST+A is the stronger of the two: yield strength 865 MPa (125 ksi) against 600 MPa (87 ksi) for Nimonic 115-ST, about 44% more; tensile strength follows at 1,240 MPa (180 ksi) vs 960 MPa (139 ksi). In exchange, Nimonic 115-ST is the more ductile: elongation 33% versus 25% for Nimonic 115 ST+A, and Nimonic 115 ST+A is harder (39 HRC vs 25 HRC). Nimonic 115 ST+A runs hotter in service (980°C vs 900°C continuous).
Nimonic 115-STChoose it when the part is bent, formed or impact-loaded.
Nimonic 115 ST+AChoose it when strength drives the design, or when the part sees heat.
Nimonic 115-ST vs Nimonic 115 ST+A: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all nickel alloy 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 nickel alloy 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.
Nimonic 115-STNimonic 115 ST+A
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 224 GPa32.5 Msi · Shear Modulus 85 GPa12.3 Msi · Bulk Modulus 190 GPa27.6 Msi · Poisson's Ratio 0.31 · Shear Strength 760 MPa110 ksi · Fatigue Strength (Endurance Limit) 480 MPa69.6 ksi · Fracture Toughness (K_IC) 90 MPa·√m81.9 ksi·√in · Charpy V-Notch Impact (RT) 25 J18.4 ft·lbf · Hardness, Brinell 360 HB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,290°C2,354 °F · Liquidus Temperature 1,360°C2,480 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 10.7 W/m·K6.2 BTU/hr·ft·°F · Specific Heat Capacity 448 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 290 J/g125 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 1.2 % IACS · Electrical Resistivity 1.39×10⁻⁶ Ω·m54.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.15 V · Corrosion Resistance 78 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Castability 60 / 100 · Brazeability / Solderability 45 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 210 MJ/kg90,284 BTU/lb · Embodied Carbon (primary production) 15 kg CO₂/kg · Embodied Water 220 L/kg26.4 gal/lb · Typical Recycled Content 30%
Strength versus weight
Yield strength against density for every nickel alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Nimonic 115-ST vs Nimonic 115 ST+A — frequently asked
Is Nimonic 115 ST+A stronger than Nimonic 115-ST?
Yes. Nimonic 115 ST+A has a typical yield strength of 865 MPa (125 ksi) against 600 MPa (87 ksi) for Nimonic 115-ST — about 44% more. Tensile strength is 1,240 MPa (180 ksi) vs 960 MPa (139 ksi).
Which condition does FabDigit quote by default, ST or ST+A?
ST+A is the default Nimonic 115 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, Nimonic 115-ST or Nimonic 115 ST+A?
Nimonic 115-ST. Its machinability rates poor (16/100) against not recommended (10/100) for Nimonic 115 ST+A; for welding the order is Nimonic 115-ST first (poor, 15/100) then Nimonic 115 ST+A (not recommended, 8/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Nimonic 115-ST and Nimonic 115 ST+A 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.