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Nickel Alloy Hastelloy G vs Hastelloy X

Nickel Alloy · grade comparison

Nickel Alloy Hastelloy G and Hastelloy X are both nickel alloy grades. Hastelloy X is the stronger of the two: yield strength 360 MPa (52.2 ksi) against 310 MPa (45 ksi) for Hastelloy G, about 16% more; tensile strength follows at 755 MPa (110 ksi) vs 690 MPa (100 ksi). In exchange, Hastelloy G is the more ductile: elongation 55% versus 43% for Hastelloy X, and Hastelloy X is harder (195 HB vs 180 HB). Hastelloy X runs hotter in service (1,150°C vs 550°C continuous). On the shop floor, Hastelloy X welds better (excellent vs very good) and Hastelloy X sits in a lower cost tier (premium, $$$) than Hastelloy G (high, $$$$).

Hastelloy GChoose it when the part is bent, formed or impact-loaded.

Hastelloy XChoose it when strength drives the design, or when the part sees heat.

Hastelloy G vs Hastelloy X: properties

Hastelloy GHastelloy X

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

198 GPa28.7 Msi
205 GPa29.7 Msi

Shear Modulus

76 GPa11 Msi
79 GPa11.5 Msi

Bulk Modulus

174 GPa25.2 Msi
190 GPa27.6 Msi

Poisson's Ratio

0.31
0.32

Tensile Strength (Ultimate)

690 MPa100 ksi
755 MPa110 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
360 MPa52.2 ksi

Elongation at Break

55%
43%

Reduction in Area

60%
55%

Shear Strength

450 MPa65.3 ksi
490 MPa71.1 ksi

Charpy V-Notch Impact (RT)

200 J148 ft·lbf
100 J73.8 ft·lbf

Hardness, Brinell

180 HB
195 HB

Hardness, Rockwell B

88 HRB
90 HRB

Compressive Strength

—
370 MPa53.7 ksi

Fracture Toughness (K_IC)

—
120 MPa·√m109 ksi·√in

Hardness, Vickers

—
205 HV

Same in both: Fatigue Strength (Endurance Limit) 300 MPa43.5 ksi

Physical

Density and transition temperatures.

Density

8.31 g/cm³0.3 lb/in³
8.22 g/cm³0.3 lb/in³

Same in both: Melting Point (Solidus) 1,260°C2,300 °F · Liquidus Temperature 1,355°C2,471 °F

Thermal

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

Thermal Conductivity

10.1 W/m·K5.8 BTU/hr·ft·°F
9.1 W/m·K5.3 BTU/hr·ft·°F

Specific Heat Capacity

445 J/kg·K0.11 BTU/lb·°F
486 J/kg·K0.12 BTU/lb·°F

Max Service Temperature (continuous)

550°C1,022 °F
1,150°C2,102 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 13.9 µm/m·K7.7 µin/in·°F · Latent Heat of Fusion 290 J/g125 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1.15×10⁻⁶ Ω·m45.3 µΩ·in
1.18×10⁻⁶ Ω·m46.5 µΩ·in

Same in both: Electrical Conductivity 1.5 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.15 V
-0.1 V

Corrosion Resistance

85 / 100
76 / 100

Manufacturability

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

Machinability

25 / 100
18 / 100

Machinability Rating (AISI 1212 = 100 %)

14%
12%

Weldability

70 / 100
85 / 100

Formability (cold)

75 / 100
70 / 100

Brazeability / Solderability

50 / 100
80 / 100

Castability

—
55 / 100

Same in both: Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

145 MJ/kg62,339 BTU/lb
215 MJ/kg92,433 BTU/lb

Embodied Carbon (primary production)

11 kg CO₂/kg
13.5 kg CO₂/kg

Embodied Water

210 L/kg25.2 gal/lb
520 L/kg62.3 gal/lb

Typical Recycled Content

40%
35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

83 kN·m/kg
92 kN·m/kg

Specific Stiffness (E / density)

23.8 MN·m/kg
24.9 MN·m/kg

Modulus of Resilience

243 kJ/m³
316 kJ/m³

Thermal Diffusivity

2.7 mm²/s
2.3 mm²/s

Thermal Shock Resistance Index

3
2

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.

2005001,0006.577.588.59Density (g/cm³)Yield strength (MPa) — log scaleHastelloy XHastelloy G

Manufacturing and finishing

CapabilityHastelloy GHastelloy X
CNC machining—Yes
Sheet metal—Yes
3D printing—Yes
Default condition—Solution Annealed
Relative cost$$$$ High$$$ Premium
Min. machined wall—1.5 mm
Best machined surface—Ra 1.6 µm
Electropolishing—Yes
HVOF Coating—Yes

They share 3 finishes: Gold Plating, Plasma Spray, Silver Plating.

Hastelloy G vs Hastelloy X — frequently asked

Is Hastelloy X stronger than Hastelloy G?

Yes. Hastelloy X has a typical yield strength of 360 MPa (52.2 ksi) against 310 MPa (45 ksi) for Hastelloy G — about 16% more. Tensile strength is 755 MPa (110 ksi) vs 690 MPa (100 ksi).

Which is cheaper, Hastelloy G or Hastelloy X?

Hastelloy X is the lower-cost material: it sits in the premium tier ($$$) while Hastelloy G is high ($$$$). 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, Hastelloy G or Hastelloy X?

Hastelloy G, by a small margin. Both rate poor for machinability — 25/100 against 18/100 for Hastelloy X; for welding the order is Hastelloy X first (excellent, 85/100) then Hastelloy G (very good, 70/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Hastelloy G and Hastelloy X 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.