Alloy Hastelloy S®, UNS N06635 - high-temp Ni-Co-Mo alloy

Hastelloy S, UNS N06635 - nickel alloy in accordance with AMS 5711, AMS 5838, AMS 5869, AMS 5873

Hastelloy S, N06635 – description

Hastelloy S (UNS N06635) is Ni-Co-Mo high-temperature alloy with alloying elements of tungsten, aluminum and lanthanum. It has excellent thermal stability, excellent oxidation resistance up to 1090°C and low thermal expansion. It was developed for applications involving severe cycling heating conditions where components must retain strength, ducticity, dimensional stability and metallurgical integrity after long-time exposure. Thus, Hastelloy S does not loose its strength after aging at 430-870°C.

Lanthanum is a rare earth mineral that is added to Hastelloy S to promote oxidation resistance.

Applications

Hastelloy S is used in low-stress gas turbine parts (like seal rings, where its low thermal expansion coefficients are important) and is an excellent dissimilar filler metal.

Physical and Tensile Properties

Room temperature physical properties:

• Density: 8.75 g/cm³
• Liquidus Temperature: 1335 °C
• Solidus Temperature: 1380 °C
• Electrical Resistivity: 1.28 μΩ·m

High-Temperature Coefficient of Thermal Expansion, from 20°C to:

• 100°C: 11.5 μm/m⋅K
• 200°C: 12.2 μm/m⋅K
• 315°C: 12.8 μm/m⋅K
• 425°C: 13.1 μm/m⋅K
• 540°C: 13.3 μm/m⋅K
• 650°C: 13.7 μm/m⋅K
• 760°C: 14.4 μm/m⋅K
• 870°C: 14.9 μm/m⋅K
• 980°C: 15.5 μm/m⋅K
• 1090°C: 16.0 μm/m⋅K

Specific Heat Capacity:

• 0°C: 398 J/kg⋅K
• 50°C: 414 J/kg⋅K
• 100°C: 427 J/kg⋅K
• 150°C: 440 J/kg⋅K
• 200°C: 448 J/kg⋅K
• 250°C: 456 J/kg⋅K
• 300°C: 465 J/kg⋅K
• 350°C: 473 J/kg⋅K
• 400°C: 477 J/kg⋅K
• 450°C: 481 J/kg⋅K
• 500°C: 490 J/kg⋅K
• 550°C: 494 J/kg⋅K
• 600°C: 498 J/kg⋅K
• 650°C: 502 J/kg⋅K
• 700°C: 594 J/kg⋅K
• 750°C: 594 J/kg⋅K
• 800°C: 590 J/kg⋅K
• 850°C: 594 J/kg⋅K
• 900°C: 594 J/kg⋅K
• 950°C: 598 J/kg⋅K
• 1000°C: 598 J/kg⋅K
• 1050°C: 598 J/kg⋅K
• 1100°C: 603 J/kg⋅K

Thermal Diffusivity:

• 100°C: 3.9 10^–6⋅m²/s
• 200°C: 3.9 10^–6⋅m²/s
• 300°C: 3.9 10^–6⋅m²/s
• 400°C: 4.5 10^–6⋅m²/s
• 500°C: 4.5 10^–6⋅m²/s
• 600°C: 5.2 10^–6⋅m²/s
• 700°C: 5.2 10^–6⋅m²/s
• 800°C: 5.2 10^–6⋅m²/s
• 900°C: 5.2 10^–6⋅m²/s
• 950°C: 5.2 10^–6⋅m²/s
• 1000°C: 5.8 10^–6⋅m²/s

Young's Modulus:

• 20°C: 212 GPa
• 360°C: 194 GPa
• 540°C: 182 GPa
• 650°C: 174 GPa
• 760°C: 166 GPa
• 815°C: 161 GPa
• 925°C: 151 GPa
• 1090°C: 132 GPa

Thermal Conductivity:

• 200°C: 14.0 W/m · K
• 300°C: 16.1 W/m · K
• 400°C: 17.9 W/m · K
• 500°C: 19.5 W/m · K
• 600°C: 21.0 W/m · K
• 700°C: 26.1 W/m · K
• 800°C: 26.1 W/m · K
• 900°C: 26.1 W/m · K
• 950°C: 27.1 W/m · K
• 1000°C: 28.0 W/m · K

Thermal Stability - room temperature hardness of Haynes S plate after aging in high temperature:

• as annealed: 57 HRA
• 425°C, 1000h: 57 HRA
• 425°C, 4000h: 52 HRA
• 425°C, 8000h: 52 HRA
• 425°C, 16000h: 56 HRA
• 540°C, 1000h: 64 HRA
• 540°C, 4000h: 63 HRA
• 540°C, 8000h: 65 HRA
• 540°C, 16000h: 67 HRA
• 650°C, 1000h: 57 HRA
• 650°C, 4000h: 55 HRA
• 650°C, 8000h: 56 HRA
• 650°C, 16000h: 57 HRA
• 760°C, 1000h: 57 HRA
• 760°C, 4000h: 56 HRA
• 760°C, 8000h: 57 HRA
• 760°C, 16000h: 57 HRA
• 870°C, 1000h: 56 HRA
• 870°C, 4000h: 56 HRA
• 870°C, 8000h: 54 HRA
• 870°C, 16000h: 54 HRA

Thermal Stability - room temperature elongation of Haynes S plate after aging in high temperature:

• as annealed: 54 %
• 425°C, 1000h: 60 %
• 425°C, 4000h: 60 %
• 425°C, 8000h: 55 %
• 425°C, 16000h: 56 %
• 540°C, 1000h: 46 %
• 540°C, 4000h: 44 %
• 540°C, 8000h: 38 %
• 540°C, 16000h: 39 %
• 650°C, 1000h: 57 %
• 650°C, 4000h: 54 %
• 650°C, 8000h: 50 %
• 650°C, 16000h: 49 %
• 760°C, 1000h: 55 %
• 760°C, 4000h: 52 %
• 760°C, 8000h: 46 %
• 760°C, 16000h: 47 %
• 870°C, 1000h: 58 %
• 870°C, 4000h: 56 %
• 870°C, 8000h: 53 %
• 870°C, 16000h: 56 %

Sheet - High-Temperature Tensile Properties:

• 20°C:
  • Yield strength: 444 MPa
  • Tensile strength: 844 MPa
  • Elongation: 49 %
• 540°C:
  • Yield strength: 338 MPa
  • Tensile strength: 773 MPa
  • Elongation: 50 %
• 760°C:
  • Yield strength: 311 MPa
  • Tensile strength: 574 MPa
  • Elongation: 70 %
• 870°C:
  • Yield strength: 218 MPa
  • Tensile strength: 341 MPa
  • Elongation: 47 %
• 980°C:
  • Yield strength: 110 MPa
  • Tensile strength: 193 MPa
  • Elongation: 46 %
• 1090°C:
  • Yield strength: 52 MPa
  • Tensile strength: 110 MPa
  • Elongation: 75 %

Plate - High-Temperature Tensile Properties:

• 20°C:
  • Yield strength: 383 MPa
  • Tensile strength: 849 MPa
  • Elongation: 55 %
• 100°C:
  • Yield strength: 365 MPa
  • Tensile strength: 814 MPa
  • Elongation: 60 %
• 200°C:
  • Yield strength: 331 MPa
  • Tensile strength: 789 MPa
  • Elongation: 59 %
• 315°C:
  • Yield strength: 291 MPa
  • Tensile strength: 756 MPa
  • Elongation: 63 %
• 425°C:
  • Yield strength: 297 MPa
  • Tensile strength: 751 MPa
  • Elongation: 62 %
• 540°C:
  • Yield strength: 283 MPa
  • Tensile strength: 727 MPa
  • Elongation: 61 %
• 760°C:
  • Yield strength: 271 MPa
  • Tensile strength: 547 MPa
  • Elongation: 69 %
• 870°C:
  • Yield strength: 233 MPa
  • Tensile strength: 363 MPa
  • Elongation: 57 %
• 980°C:
  • Yield strength: 135 MPa
  • Tensile strength: 228 MPa
  • Elongation: 62 %
• 1090°C:
  • Yield strength: 61 MPa
  • Tensile strength: 117 MPa
  • Elongation: 69 %

Rupture Strength, Sheet:

• 650°C, 10h: 431 MPa
• 650°C, 100h: 345 MPa
• 650°C, 1000h: 262 MPa
• 730°C, 10h: 269 MPa
• 730°C, 100h: 194 MPa
• 730°C, 1000h: 139 MPa
• 815°C, 10h: 162 MPa
• 815°C, 100h: 103 MPa
• 815°C, 1000h: 68 MPa
• 930°C, 10h: 66 MPa
• 930°C, 100h: 40 MPa

Rupture Strength, Plate:

• 650°C, 10h: 552 MPa
• 650°C, 100h: 400 MPa
• 650°C, 1000h: 186 MPa
• 700°C, 10h: 386 MPa
• 700°C, 100h: 262 MPa
• 700°C, 1000h: 110 MPa
• 730°C, 10h: 262 MPa
• 730°C, 100h: 169 MPa
• 730°C, 1000h: 68 MPa
• 815°C, 10h: 172 MPa
• 815°C, 100h: 110 MPa
• 815°C, 1000h: 40 MPa
• 870°C, 10h: 114 MPa
• 870°C, 100h: 68 MPa
• 870°C, 1000h: 21 MPa

Creep Strength for 0,5% max elongation, Sheet:

• 650°C, 10h: 345 MPa
• 650°C, 100h: 245 MPa
• 650°C, 1000h: 165 MPa
• 730°C, 10h: 172 MPa
• 730°C, 100h: 112 MPa
• 730°C, 1000h: 72 MPa
• 815°C, 10h: 81 MPa
• 815°C, 100h: 48 MPa

Creep Strength for 0,5% max elongation, Plate:

• 650°C, 10h: 372 MPa
• 650°C, 100h: 255 MPa
• 650°C, 1000h: 131 MPa
• 705°C, 10h: 200 MPa
• 705°C, 100h: 114 MPa
• 705°C, 1000h: 62 MPa
• 760°C, 10h: 117 MPa
• 760°C, 100h: 63 MPa
• 760°C, 1000h: 33 MPa
• 815°C, 10h: 69 MPa
• 815°C, 100h: 39 MPa
• 815°C, 1000h: 21 MPa
• 870°C, 10h: 43 MPa
• 870°C, 100h: 24 MPa
• 870°C, 100h: 13 MPa

Corrosion Resistance

Excellent oxidation resistance up to 1090°C.

1008h long static oxidation in flowing air test results:

• 980°C:
  • Metal loss: 0.005 mm
  • Internal Penetration: 0.012 mm
• 1095°C:
  • Metal loss: 0.011 mm
  • Average metal affected: 0.033 mm
• 1150°C:
  • Metal loss: 0.026 mm
  • Average metal affected: 0.042 mm

Heat Treatment, Working and Machining

Standard recommended working and heat treatment parameters:

• Hot forming: 1145-870 °C
• Finishing: 1050-815 °C
• Solution-treatment: 1066°C

Hastelloy S can be cold forged and hot forged. Hot forging should have two steps: first forge from 1145 to 870°C up to the final 20% cross-section reduction. Then finish the remaining 20% from 1040 to 815°C.

Due to the thermal stability of the alloy, the cooling rate after annealing has virtually no effect on the properties.

Weldability

Decent weldability by both manual and automatic methods.